PATENT DOCUMENT

Publication Number: US-11696060-B2
Application Number: US-202217857947-A
Country: US
Kind Code: B2

Title: User identification using headphones

Abstract:
Systems and processes for user identification using headphones associated with a first device are provided. For example, first movement information corresponding to movement of a second electronic device is detected. Second movement information corresponding to movement of a third electronic device is detected. A similarity score is determined based on the first movement information and the second movement information. In accordance with a determination that the similarity score is above a threshold similarity score, a user is identified as an authorized user of the first electronic device and the second electronic device. Based on the identification, an output is provided to the second electronic device.

Claims:
What is claimed is: 
     
       1. An electronic device, comprising:
 one or more processors; 
 a memory; and 
 one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs including instructions for:
 detecting first movement information corresponding to movement of a second electronic device; 
 detecting second movement information corresponding to movement of a third electronic device; 
 determining a similarity score based on the first movement information and the second movement information; 
 in accordance with a determination that the similarity score is above a threshold similarity score:
 identifying a user as an authorized user of the electronic device and the second electronic device; and 
 
 providing, based on the identification, an output to the second electronic device. 
 
 
     
     
       2. The device of  claim 1 , wherein the user is identified as an authorized user based on the determination that the similarity score is above the threshold similarity score. 
     
     
       3. The device of  claim 1 , wherein the second electronic device includes at least one in-ear headphone and at least one microphone. 
     
     
       4. The device of  claim 1 , wherein detecting first movement information corresponding to movement of the second electronic device comprises:
 determining whether the first movement information corresponds to a first movement profile, wherein the first movement profile includes a known movement pattern of a first device type. 
 
     
     
       5. The device of  claim 4 , wherein the first movement profile comprises:
 a first position corresponding to a resting position; 
 a second position corresponding to an in-ear position; and 
 a movement pattern from the first position to the second position, wherein the movement pattern includes expected acceleration from a plurality of axes associated with the second electronic device. 
 
     
     
       6. The device of  claim 1 , wherein the third electronic device corresponds to an electronic watch. 
     
     
       7. The device of  claim 1 , wherein detecting second movement information corresponding to movement of the third electronic device comprises:
 determining whether the second movement information corresponds to a second movement profile, wherein the second movement profile corresponds to a known movement pattern of a second device type. 
 
     
     
       8. The device of  claim 7 , wherein the second movement profile comprises:
 a first motion corresponding to obtaining an item from a first position; 
 a second motion corresponding to releasing an item to a second position; and 
 a movement pattern from the first position to the second position, wherein the movement pattern includes expected acceleration from a plurality of axes associated with the third electronic device. 
 
     
     
       9. The device of  claim 1 , wherein detecting first movement information corresponding to movement of the second electronic device comprises:
 receiving, from the second electronic device, a plurality of signals associated with at least one accelerometer of the second electronic device; 
 determining a root square sum of the plurality of signals; and 
 obtaining the first movement information based on the root square sum. 
 
     
     
       10. The device of  claim 1 , wherein detecting second movement information corresponding to movement of the third electronic device comprises:
 receiving, from the third electronic device, a plurality of signals associated with an accelerometer of the third electronic device; 
 determining a root square sum of the plurality of signals; and 
 obtaining the second movement information based on the root square sum. 
 
     
     
       11. The device of  claim 1 , wherein determining the similarity score based on the first movement information and the second movement information comprises:
 providing the first movement information and the second movement information to a time function; and 
 receiving, as an output from the time function, the similarity score. 
 
     
     
       12. The device of  claim 1 , wherein identifying the user as an authorized user of the first electronic device and the second electronic device comprises:
 in accordance with a determination that valid authentication information was received from the user at the third electronic device:
 identifying the user as an authorized user of the first electronic device and the second electronic device. 
 
 
     
     
       13. The device of  claim 1 , wherein identifying the user as an authorized user of the first electronic device and the second electronic device comprises:
 obtaining, from the second electronic device, biometric information; 
 in accordance with a determination that the obtained biometric information corresponds to reference biometric information:
 identifying the user as an authorized user of the first electronic device and the second electronic device. 
 
 
     
     
       14. The device of  claim 1 , wherein identifying the user as an authorized user of the first electronic device and the second electronic device comprises:
 detecting a first light profile, wherein the first light profile corresponds to changes in light during the movement of the second electronic device; 
 detecting a second light profile, wherein the second light profile corresponds to changes in light during the movement of the third electronic device; 
 determining a second similarity score based on a comparison of the first light profile and the second light profile; and 
 in accordance with a determination that the second similarity score is above a second threshold similarity score, identifying the user as an authorized user of the first electronic device and the second electronic device. 
 
     
     
       15. The device of  claim 1 , wherein identifying the user as an authorized user of the first electronic device and the second electronic device comprises:
 detecting a first sound profile, wherein the first sound profile corresponds to changes in audio amplitude during the movement of the second electronic device; 
 detecting a second sound profile, wherein the second sound profile corresponds to changes in audio amplitude during the movement of the third electronic device; 
 determining a third similarity score based on a comparison of the first sound profile and the second sound profile; and 
 in accordance with a determination that the third similarity score is above a third threshold similarity score, identifying the user as an authorized user of the first electronic device and the second electronic device. 
 
     
     
       16. The device of  claim 1 , the one or more programs including instructions for:
 in accordance with a determination that the similarity score is not above a threshold similarity score:
 determining whether personalized media is playing at the second electronic device; and 
 in accordance with a determination that personalized media is playing at the second electronic device, ceasing playback of the personalized media the second electronic device. 
 
 
     
     
       17. The device of  claim 1 , the one or more programs including instructions for:
 in accordance with a determination that the similarity score is not above a threshold similarity score:
 determining whether the similarity score is above a second threshold similarity score, wherein the second threshold similarity score is lower than the threshold similarity score; 
 in accordance with a determination that the similarity score is above the second threshold similarity score:
 providing, at the first electronic device, a prompt; 
 receiving an input responsive to the prompt; 
 identifying, based on the input, the user as an authorized user of the first electronic device and the second electronic device; and 
 providing, based on the identification, an output to the second electronic device. 
 
 
 
     
     
       18. A computer-implemented method, comprising:
 at a first electronic device with one or more processors and memory:
 detecting first movement information corresponding to movement of a second electronic device; 
 detecting second movement information corresponding to movement of a third electronic device; 
 determining a similarity score based on the first movement information and the second movement information; 
 in accordance with a determination that the similarity score is above a threshold similarity score:
 identifying a user as an authorized user of the first electronic device and the second electronic device; and 
 providing, based on the identification, an output to the second electronic device. 
 
 
 
     
     
       19. The method of  claim 18 , wherein the user is identified as an authorized user based on the determination that the similarity score is above the threshold similarity score. 
     
     
       20. The method of  claim 18 , wherein the second electronic device includes at least one in-ear headphone and at least one microphone. 
     
     
       21. The method of  claim 18 , wherein detecting first movement information corresponding to movement of the second electronic device comprises:
 determining whether the first movement information corresponds to a first movement profile, wherein the first movement profile includes a known movement pattern of a first device type. 
 
     
     
       22. The method of  claim 21 , wherein the first movement profile comprises:
 a first position corresponding to a resting position; 
 a second position corresponding to an in-ear position; and 
 a movement pattern from the first position to the second position, wherein the movement pattern includes expected acceleration from a plurality of axes associated with the second electronic device. 
 
     
     
       23. The method of  claim 18 , wherein the third electronic device corresponds to an electronic watch. 
     
     
       24. The method of  claim 18 , wherein detecting second movement information corresponding to movement of the third electronic device comprises:
 determining Whether the second movement information corresponds to a second movement profile, wherein the second movement profile corresponds to a known movement pattern of a second device type. 
 
     
     
       25. The method of  claim 24 , wherein the second movement profile comprises:
 a first motion corresponding to obtaining an item from a first position; 
 a second motion corresponding to releasing an item to a second position; and 
 a movement pattern from the first position to the second position, wherein the movement pattern includes expected acceleration from a plurality of axes associated with the third electronic device. 
 
     
     
       26. The method of  claim 18 , wherein detecting first movement information corresponding, to movement of the second electronic device comprises:
 receiving, from the second electronic device, a plurality of signals associated with at least one accelerometer of the second electronic device; 
 determining a root square sum of the plurality of signals; and 
 obtaining the first movement information based on the root square sum. 
 
     
     
       27. The method of  claim 18 , wherein detecting second movement information corresponding to movement of the third electronic device comprises:
 receiving, from the third electronic device, a plurality of signals associated with an accelerometer of the third electronic device; 
 determining a root square sum of the plurality of signals; and 
 obtaining the second movement information based on the root square sum. 
 
     
     
       28. The method of  claim 18 , wherein determining the similarity score based on the first movement information and the second movement information comprises:
 providing the first movement information and the second movement information to a time function; and 
 receiving, as an output from the time function, the similarity score. 
 
     
     
       29. The method of  claim 18 , wherein identifying the user as an authorized user of the first electronic device and the second electronic device comprises:
 in accordance with a determination that valid authentication information was received from the user at the third electronic device:
 identifying the user as an authorized user of the first electronic device and the second electronic device. 
 
 
     
     
       30. The method of  claim 18 , wherein identifying the user as an authorized user of the first electronic device and the second electronic device comprises:
 obtaining, from the second electronic device, biometric information; 
 in accordance with a determination that the obtained biometric information corresponds to reference biometric information:
 identifying the user as an authorized user of the first electronic device and the second electronic device. 
 
 
     
     
       31. The method of  claim 18 , wherein identifying the user as an authorized user of the first electronic device and the second electronic device comprises:
 detecting a first light profile, wherein the first light profile corresponds to changes in light during the movement of the second electronic device; 
 detecting a second light profile, wherein the second light profile corresponds to changes in light during the movement of the third electronic device; 
 determining a second similarity score based on a comparison of the first light profile and the second light profile; and 
 in accordance with a determination that the second similarity score is above a second threshold similarity score, identifying the user as an authorized user of the first electronic device and the second electronic device. 
 
     
     
       32. The method of  claim 18 , wherein identifying the user as an authorized user of the first electronic device and the second electronic device comprises:
 detecting a first sound profile, wherein the first sound profile corresponds to changes in audio amplitude during the movement of the second electronic device; 
 detecting a second sound profile, wherein the second sound profile corresponds to changes in audio amplitude during the movement of the third electronic device; 
 determining a third similarity score based on a comparison of the first sound profile and the second sound profile; and 
 in accordance with a determination that the third similarity score is above a third threshold similarity score, identifying the user as an authorized user of the first electronic device and the second electronic device. 
 
     
     
       33. The method of  claim 18 , comprising:
 in accordance with a determination that the similarity score is not above a threshold similarity score:
 determining whether personalized media is playing at the second electronic device; and 
 in accordance with a determination that personalized media is playing at the second electronic device, ceasing playback of the personalized media the second electronic device. 
 
 
     
     
       34. The method of  claim 18 , comprising:
 in accordance with a determination that the similarity score is not above a threshold similarity score:
 determining whether the similarity score is above a second threshold similarity score, wherein the second threshold similarity score is lower than the threshold similarity score; 
 in accordance with a determination that the similarity score is above the second threshold similarity score:
 providing, at the first electronic device, a prompt; 
 receiving an input responsive to the prompt; 
 identifying, based on the input, the user as an authorized user of the first electronic device and the second electronic device; and 
 providing, based on the identification, an output to the second electronic device. 
 
 
 
     
     
       35. A non-transitory computer-readable storage medium storing one or more programs, the one or more programs comprising instructions, which when executed by one or more processors of a first electronic device, cause the first electronic device to:
 detect first movement information corresponding to movement of a second electronic device; 
 detect second movement information corresponding to movement of a third electronic device; 
 determine a similarity score based on the first movement information and the second movement information; 
 in accordance with a determination that the similarity score is above a threshold similarity score:
 identify a user as an authorized user of the first electronic device and the second electronic device; and 
 provide, based on the identification, an output to the second electronic device. 
 
 
     
     
       36. The computer-readable storage medium of  claim 35 , wherein the user is identified as an authorized user based on the determination that the similarity score is above the threshold similarity score. 
     
     
       37. The computer-readable storage medium of  claim 35 , wherein the second electronic device includes at least one in-ear headphone and at least one microphone. 
     
     
       38. The computer-readable storage medium of  claim 35 , wherein detecting first movement information corresponding to movement of the second electronic device comprises:
 determining whether the first movement information corresponds to a first movement profile, wherein the first movement profile includes a known movement pattern of a first device type. 
 
     
     
       39. The computer-readable storage medium of  claim 38 , wherein the first movement profile comprises:
 a first position corresponding to a resting position; 
 a second position corresponding to an in-ear position; and 
 a movement pattern from the first position to the second position, wherein the movement pattern includes expected acceleration from a plurality of axes associated with the second electronic device. 
 
     
     
       40. The computer-readable storage medium of  claim 35 , wherein the third electronic device corresponds to an electronic watch. 
     
     
       41. The computer-readable storage medium of  claim 35 , wherein detecting second movement information corresponding to movement of the third electronic device comprises:
 determining whether the second movement information corresponds to a second movement profile, wherein the second movement profile corresponds to a known movement pattern of a second device type. 
 
     
     
       42. The computer-readable storage medium of  claim 41 , wherein the second movement profile comprises:
 a first motion corresponding to obtaining an item from a first position; 
 a second motion corresponding to releasing an item to a second position; and 
 a movement pattern from the first position to the second position, wherein the movement pattern includes expected acceleration from a plurality of axes associated with the third electronic device. 
 
     
     
       43. The computer-readable storage medium of  claim 35 . wherein detecting first movement information corresponding to movement of the second electronic device comprises:
 receiving, from the second electronic device, a plurality of signals associated with at least one accelerometer of the second electronic device: 
 determining a root square sum of the plurality of signals; and 
 obtaining the first movement information based on the root square sum. 
 
     
     
       44. The computer-readable storage medium of  claim 35 , wherein detecting second movement information corresponding to movement of the third electronic device comprises:
 receiving, from the third electronic device, a plurality of signals associated with an accelerometer of the third electronic device:
 determining a root square sum of the plurality of signals; and 
 obtaining the second movement information based on the root square sum. 
 
 
     
     
       45. The computer-readable storage medium of  claim 35 , wherein determining the similarity score based on the first movement information and the second movement information comprises:
 providing the first movement information and the second movement information to a time function: and 
 receiving, as an output from the time function, the similarity score. 
 
     
     
       46. The computer-readable storage medium of  claim 24 , wherein identifying the user as an authorized user of the first electronic device and the second electronic device comprises:
 in accordance with a determination that valid authentication information was received from the user at the third electronic device:
 identifying the user as an authorized user of the first electronic device and the second electronic device. 
 
 
     
     
       47. The computer-readable storage medium of  claim 35 , wherein identifying the user as an authorized user of the first electronic device and the second electronic device comprises:
 obtaining, from the second electronic device, biometric information; 
 in accordance with a determination that the obtained biometric information corresponds to reference biometric information:
 identifying the user as an authorized user of the first electronic device and the second electronic device. 
 
 
     
     
       48. The computer-readable storage medium of  claim 35 , wherein identifying the user as an authorized user of the first electronic device and the second electronic device comprises:
 detecting a first light profile, wherein the first light profile corresponds to changes in light during the movement of the second electronic device; 
 detecting a second light profile, wherein the second light profile corresponds to changes in light during the movement of the third electronic device; 
 determining a second similarity score based on a comparison of the first light profile and the second light profile; and 
 in accordance with a determination that the second similarity score is above a second threshold similarity score, identifying the user as an authorized user of the first electronic device and the second electronic device. 
 
     
     
       49. The computer-readable storage medium of  claim 35 , wherein identifying the user as an authorized user of the first electronic device and the second electronic device comprises:
 detecting a first sound profile, wherein the first sound profile corresponds to changes in audio amplitude during the movement of the second electronic device; 
 detecting a second sound profile, wherein the second sound profile corresponds to changes in audio amplitude during the movement of the third electronic device; 
 determining a third similarity score based on a comparison of the first sound profile and the second sound profile; and 
 in accordance with a determination that the third similarity score is above a third threshold similarity score, identifying the user as an authorized user of the first electronic device and the second electronic device. 
 
     
     
       50. The computer-readable storage medium of  claim 35 , wherein the instructions cause the first electronic device to:
 in accordance with a determination that the similarity score is not above a threshold similarity score:
 determine whether personalized media is playing at the second electronic device; and 
 in accordance with a determination that personalized media is playing at the second electronic device, cease playback of the personalized media the second electronic device. 
 
 
     
     
       51. The computer-readable storage medium of  claim 35 , wherein the instructions cause the first electronic device to:
 in accordance with a determination that the similarity score is not above a threshold similarity score:
 determine Whether the similarity score is above a second threshold similarity score, wherein the second threshold similarity score is lower than the threshold similarity score; 
 in accordance with a determination that the similarity score is above the second threshold similarity score:
 provide, at the first electronic device, a prompt; 
 receive an input responsive to the prompt; 
 identify, based on the input, the user as an authorized user of the first electronic device and the second electronic device; and 
 provide, based on the identification, an output to the second electronic device.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. application Ser. No. 16/992,629, entitled “USER IDENTIFICATION USING HEADPHONES,” filed Aug. 13, 2020, which claims the benefit of U.S. Provisional Application No. 63/054,660, entitled “USER IDENTIFICATION USING HEADPHONES,” filed Jul. 21, 2020, the content of each of which is hereby incorporated by reference in their entirety for all purposes. 
    
    
     FIELD 
     This application relates generally to user identification and, more specifically, to user identification using headphones. 
     BACKGROUND 
     Headphones, such as headphones communicatively coupled to an electronic device, can provide a useful interface between human users and electronic devices. In general, headphones may be utilized for listening to audio from another device and performing other various functions, such as providing voice commands to the device via the headphones. For example, a user may provide a speech input containing a user request to a digital assistant operating on an electronic device such as a mobile device. The digital assistant can interpret the user&#39;s intent from the speech input and operationalize the user&#39;s intent into tasks. Various outputs can also be provided to the user through the headphones. For example, upon receipt of a message at the mobile device, such as an instant message, an audible representation of the message may be provided to the user via the headphones. However, conventional systems do not address whether the user wearing the headphones is authorized to interact with personal features of the device, such as receiving messages from the device. Accordingly, improved systems for user identification using headphones is desired. 
     SUMMARY 
     Systems and processes for user identification using headphones associated with a first device (e.g., a smartphone) are provided. For example, first movement information corresponding to movement of a second electronic device (e.g., a headphone) is detected. Second movement information corresponding to movement of a third electronic device (e.g., a smartwatch) is detected. A similarity score is determined based on the first movement information and the second movement information. In accordance with a determination that the similarity score is above a threshold similarity score, a user is identified as an authorized user of the first electronic device and the second electronic device. Based on the identification, an output is provided to the second electronic device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a block diagram illustrating a system and environment for implementing a digital assistant, according to various examples. 
         FIG.  2 A  is a block diagram illustrating a portable multifunction device implementing the client-side portion of a digital assistant, according to various examples. 
         FIG.  2 B  is a block diagram illustrating exemplary components for event handling, according to various examples. 
         FIG.  3    illustrates a portable multifunction device implementing the client-side portion of a digital assistant, according to various examples. 
         FIG.  4    is a block diagram of an exemplary multifunction device with a display and a touch-sensitive surface, according to various examples. 
         FIG.  5 A  illustrates an exemplary user interface for a menu of applications on a portable multifunction device, according to various examples. 
         FIG.  5 B  illustrates an exemplary user interface for a multifunction device with a touch-sensitive surface that is separate from the display, according to various examples. 
         FIG.  6 A  illustrates a personal electronic device, according to various examples. 
         FIG.  6 B  is a block diagram illustrating a personal electronic device, according to various examples. 
         FIG.  7 A  is a block diagram illustrating a digital assistant system or a server portion thereof, according to various examples. 
         FIG.  7 B  illustrates the functions of the digital assistant shown in  FIG.  7 A , according to various examples. 
         FIG.  7 C  illustrates a portion of an ontology, according to various examples. 
         FIGS.  8 A- 8 C  illustrate a system for user identification using headphones. 
         FIG.  9    illustrates a system for user identification using headphones. 
         FIG.  10    illustrates a process for user identification using headphones. 
         FIG.  11    illustrates a process for user identification using headphones. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description of examples, reference is made to the accompanying drawings in which are shown by way of illustration specific examples that can be practiced. It is to be understood that other examples can be used and structural changes can be made without departing from the scope of the various examples. 
     Conventional systems are generally lacking with respect to user identification using headphones. In particular, traditional systems are not well equipped to determine whether a user wearing a respective set of headphones is an authorized user of a corresponding device, such as a mobile phone. In particular, these systems typically do not include functionality for considering whether the user wearing the headphones is associated with a corresponding device, much less do these systems perform authentication techniques and modify the types of outputs provided at the corresponding device based on the authentication. For example, conventional systems will typically allow any user (e.g., an unauthorized user) to place headphones in their ear, even if such headphones are communicatively coupled to the device of another user. As a result, conventional systems may risk releasing personal information from an associated device to unauthorized wearers of corresponding headphones. 
     Although the following description uses terms “first,” “second,” etc. to describe various elements, these elements should not be limited by the terms. These terms are only used to distinguish one element from another. For example, a first input could be termed a second input, and, similarly, a second input could be termed a first input, without departing from the scope of the various described examples. The first input and the second input are both inputs and, in some cases, are separate and different inputs. 
     The terminology used in the description of the various described examples herein is for the purpose of describing particular examples only and is not intended to be limiting. As used in the description of the various described examples and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that the term “and/or” as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. It will be further understood that the terms “includes,” “including,” “comprises,” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     The term “if” may be construed to mean “when” or “upon” or “in response to determining” or “in response to detecting,” depending on the context. Similarly, the phrase “if it is determined” or “if [a stated condition or event] is detected” may be construed to mean “upon determining” or “in response to determining” or “upon detecting [the stated condition or event]” or “in response to detecting [the stated condition or event],” depending on the context. 
     1. System and Environment 
       FIG.  1    illustrates a block diagram of system  100  according to various examples. In some examples, system  100  implements a digital assistant. The terms “digital assistant,” “virtual assistant,” “intelligent automated assistant,” or “automatic digital assistant” refer to any information processing system that interprets natural language input in spoken and/or textual form to infer user intent, and performs actions based on the inferred user intent. For example, to act on an inferred user intent, the system performs one or more of the following: identifying a task flow with steps and parameters designed to accomplish the inferred user intent, inputting specific requirements from the inferred user intent into the task flow; executing the task flow by invoking programs, methods, services, APIs, or the like; and generating output responses to the user in an audible (e.g., speech) and/or visual form. 
     Specifically, a digital assistant is capable of accepting a user request at least partially in the form of a natural language command, request, statement, narrative, and/or inquiry. Typically, the user request seeks either an informational answer or performance of a task by the digital assistant. A satisfactory response to the user request includes a provision of the requested informational answer, a performance of the requested task, or a combination of the two. For example, a user asks the digital assistant a question, such as “Where am I right now?” Based on the user&#39;s current location, the digital assistant answers, “You are in Central Park near the west gate.” The user also requests the performance of a task, for example, “Please invite my friends to my girlfriend&#39;s birthday party next week.” In response, the digital assistant can acknowledge the request by saying “Yes, right away,” and then send a suitable calendar invite on behalf of the user to each of the user&#39;s friends listed in the user&#39;s electronic address book. During performance of a requested task, the digital assistant sometimes interacts with the user in a continuous dialogue involving multiple exchanges of information over an extended period of time. There are numerous other ways of interacting with a digital assistant to request information or performance of various tasks. In addition to providing verbal responses and taking programmed actions, the digital assistant also provides responses in other visual or audio forms, e.g., as text, alerts, music, videos, animations, etc. 
     As shown in  FIG.  1   , in some examples, a digital assistant is implemented according to a client-server model. The digital assistant includes client-side portion  102  (hereafter “DA client  102 ”) executed on user device  104  and server-side portion  106  (hereafter “DA server  106 ”) executed on server system  108 . DA client  102  communicates with DA server  106  through one or more networks  110 . DA client  102  provides client-side functionalities such as user-facing input and output processing and communication with DA server  106 . DA server  106  provides server-side functionalities for any number of DA clients  102  each residing on a respective user device  104 . 
     In some examples, DA server  106  includes client-facing I/O interface  112 , one or more processing modules  114 , data and models  116 , and I/O interface to external services  118 . The client-facing I/O interface  112  facilitates the client-facing input and output processing for DA server  106 . One or more processing modules  114  utilize data and models  116  to process speech input and determine the user&#39;s intent based on natural language input. Further, one or more processing modules  114  perform task execution based on inferred user intent. In some examples, DA server  106  communicates with external services  120  through network(s)  110  for task completion or information acquisition. I/O interface to external services  118  facilitates such communications. 
     User device  104  can be any suitable electronic device. In some examples, user device  104  is a portable multifunctional device (e.g., device  200 , described below with reference to  FIG.  2 A ), a multifunctional device (e.g., device  400 , described below with reference to  FIG.  4   ), or a personal electronic device (e.g., device  600 , described below with reference to  FIG.  6 A-B .) A portable multifunctional device is, for example, a mobile telephone that also contains other functions, such as PDA and/or music player functions. Specific examples of portable multifunction devices include the Apple Watch®, iPhone®, iPod Touch®, and iPad® devices from Apple Inc. of Cupertino, Calif. Other examples of portable multifunction devices include, without limitation, earphones/headphones, speakers, and laptop or tablet computers. Further, in some examples, user device  104  is a non-portable multifunctional device. In particular, user device  104  is a desktop computer, a game console, a speaker, a television, or a television set-top box. In some examples, user device  104  includes a touch-sensitive surface (e.g., touch screen displays and/or touchpads). Further, user device  104  optionally includes one or more other physical user-interface devices, such as a physical keyboard, a mouse, and/or a joystick. Various examples of electronic devices, such as multifunctional devices, are described below in greater detail. 
     Examples of communication network(s)  110  include local area networks (LAN) and wide area networks (WAN), e.g., the Internet. Communication network(s)  110  is implemented using any known network protocol, including various wired or wireless protocols, such as, for example, Ethernet, Universal Serial Bus (USB), FIREWIRE Global System for Mobile Communications (GSM), Enhanced Data. GSM Environment (EDGE), code division multiple access (CDMA), time division multiple access (TDMA), Bluetooth, Wi-Fi, voice over Internet Protocol (VoIP), Wi-MAX, or any other suitable communication protocol. 
     Server system  108  is implemented on one or more standalone data processing apparatus or a distributed network of computers. In some examples, server system  108  also employs various virtual devices and/or services of third-party service providers (e.g., third-party cloud service providers) to provide the underlying computing resources and/or infrastructure resources of server system  108 . 
     In some examples, user device  104  communicates with DA server  106  via second user device  122 . Second user device  122  is similar or identical to user device  104 . For example, second user device  122  is similar to devices  200 ,  400 , or  600  described below with reference to  FIGS.  2 A,  4 , and  6 A -B. User device  104  is configured to communicatively couple to second user device  122  via a direct communication connection, such as Bluetooth, NFC, BTLE, or the like, or via a wired or wireless network, such as a local Wi-Fi network. In some examples, second user device  122  is configured to act as a proxy between user device  104  and DA server  106 . For example, DA client  102  of user device  104  is configured to transmit information (e.g., a user request received at user device  104 ) to DA server  106  via second user device  122 . DA server  106  processes the information and returns relevant data (e.g., data content responsive to the user request) to user device  104  via second user device  122 . 
     In some examples, user device  104  is configured to communicate abbreviated requests for data to second user device  122  to reduce the amount of information transmitted from user device  104 . Second user device  122  is configured to determine supplemental information to add to the abbreviated request to generate a complete request to transmit to DA server  106 . This system architecture can advantageously allow user device  104  having limited communication capabilities and/or limited battery power (e.g., a watch or a similar compact electronic device) to access services provided by DA server  106  by using second user device  122 , having greater communication capabilities and/or battery power (e.g., a mobile phone, laptop computer, tablet computer, or the like), as a proxy to DA server  106 . While only two user devices  104  and  122  are shown in  FIG.  1   , it should be appreciated that system  100 , in some examples, includes any number and type of user devices configured in this proxy configuration to communicate with DA server system  106 . 
     Although the digital assistant shown in  FIG.  1    includes both a client-side portion (e.g., DA client  102 ) and a server-side portion (e.g., DA server  106 ), in some examples, the functions of a digital assistant are implemented as a standalone application installed on a user device. In addition, the divisions of functionalities between the client and server portions of the digital assistant can vary in different implementations. For instance, in some examples, the DA client is a thin-client that provides only user-facing input and output processing functions, and delegates all other functionalities of the digital assistant to a backend server. 
     2. Electronic Devices 
     Attention is now directed toward embodiments of electronic devices for implementing the client-side portion of a digital assistant.  FIG.  2 A  is a block diagram illustrating portable multifunction device  200  with touch-sensitive display system  212  in accordance with some embodiments. Touch-sensitive display  212  is sometimes called a “touch screen” for convenience and is sometimes known as or called a “touch-sensitive display system.” Device  200  includes memory  202  (which optionally includes one or more computer-readable storage mediums), memory controller  222 , one or more processing units (CPUs)  220 , peripherals interface  218 , RF circuitry  208 , audio circuitry  210 , speaker  211 , microphone  213 , input/output (I/O) subsystem  206 , other input control devices  216 , and external port  224 . Device  200  optionally includes one or more optical sensors  264 . Device  200  optionally includes one or more contact intensity sensors  265  for detecting intensity of contacts on device  200  (e.g., a touch-sensitive surface such as touch-sensitive display system  212  of device  200 ). Device  200  optionally includes one or more tactile output generators  267  for generating tactile outputs on device  200  (e.g., generating tactile outputs on a touch-sensitive surface such as touch-sensitive display system  212  of device  200  or touchpad  455  of device  400 ). These components optionally communicate over one or more communication buses or signal lines  203 . 
     As used in the specification and claims, the term “intensity” of a contact on a touch-sensitive surface refers to the force or pressure (force per unit area) of a contact (e.g., a finger contact) on the touch-sensitive surface, or to a substitute (proxy) for the force or pressure of a contact on the touch-sensitive surface. The intensity of a contact has a range of values that includes at least four distinct values and more typically includes hundreds of distinct values (e.g., at least 256). Intensity of a contact is, optionally, determined (or measured) using various approaches and various sensors or combinations of sensors. For example, one or more force sensors underneath or adjacent to the touch-sensitive surface are, optionally, used to measure force at various points on the touch-sensitive surface. In some implementations, force measurements from multiple force sensors are combined (e.g., a weighted average) to determine an estimated force of a contact. Similarly, a pressure-sensitive tip of a stylus is, optionally, used to determine a pressure of the stylus on the touch-sensitive surface. Alternatively, the size of the contact area detected on the touch-sensitive surface and/or changes thereto, the capacitance of the touch-sensitive surface proximate to the contact and/or changes thereto, and/or the resistance of the touch-sensitive surface proximate to the contact and/or changes thereto are, optionally, used as a substitute for the force or pressure of the contact on the touch-sensitive surface. In some implementations, the substitute measurements for contact force or pressure are used directly to determine whether an intensity threshold has been exceeded (e.g., the intensity threshold is described in units corresponding to the substitute measurements). In some implementations, the substitute measurements for contact force or pressure are converted to an estimated force or pressure, and the estimated force or pressure is used to determine whether an intensity threshold has been exceeded (e.g., the intensity threshold is a pressure threshold measured in units of pressure). Using the intensity of a contact as an attribute of a user input allows for user access to additional device functionality that may otherwise not be accessible by the user on a reduced-size device with limited real estate for displaying affordances (e.g., on a touch-sensitive display) and/or receiving user input (e.g., via a touch-sensitive display, a touch-sensitive surface, or a physical/mechanical control such as a knob or a button). 
     As used in the specification and claims, the term “tactile output” refers to physical displacement of a device relative to a previous position of the device, physical displacement of a component (e.g., a touch-sensitive surface) of a device relative to another component (e.g., housing) of the device, or displacement of the component relative to a center of mass of the device that will be detected by a user with the user&#39;s sense of touch. For example, in situations where the device or the component of the device is in contact with a surface of a user that is sensitive to touch (e.g., a finger, palm, or other part of a user&#39;s hand), the tactile output generated by the physical displacement will be interpreted by the user as a tactile sensation corresponding to a perceived change in physical characteristics of the device or the component of the device. For example, movement of a touch-sensitive surface (e.g., a touch-sensitive display or trackpad) is, optionally, interpreted by the user as a “down click” or “up click” of a physical actuator button. In some cases, a user will feel a tactile sensation such as an “down click” or “up click” even when there is no movement of a physical actuator button associated with the touch-sensitive surface that is physically pressed (e.g., displaced) by the user&#39;s movements. As another example, movement of the touch-sensitive surface is, optionally, interpreted or sensed by the user as “roughness” of the touch-sensitive surface, even when there is no change in smoothness of the touch-sensitive surface. While such interpretations of touch by a user will be subject to the individualized sensory perceptions of the user, there are many sensory perceptions of touch that are common to a large majority of users. Thus, when a tactile output is described as corresponding to a particular sensory perception of a user (e.g., an “up click,” a “down click,” “roughness”), unless otherwise stated, the generated tactile output corresponds to physical displacement of the device or a component thereof that will generate the described sensory perception for a typical (or average) user. 
     It should be appreciated that device  200  is only one example of a portable multifunction device, and that device  200  optionally has more or fewer components than shown, optionally combines two or more components, or optionally has a different configuration or arrangement of the components. The various components shown in  FIG.  2 A  are implemented in hardware, software, or a combination of both hardware and software, including one or more signal processing and/or application-specific integrated circuits. 
     Memory  202  includes one or more computer-readable storage mediums. The computer-readable storage mediums are, for example, tangible and non-transitory. Memory  202  includes high-speed random access memory and also includes non-volatile memory, such as one or more magnetic disk storage devices, flash memory devices, or other non-volatile solid-state memory devices. Memory controller  222  controls access to memory  202  by other components of device  200 . 
     In some examples, a non-transitory computer-readable storage medium of memory  202  is used to store instructions (e.g., for performing aspects of processes described below) for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. In other examples, the instructions (e.g., for performing aspects of the processes described below) are stored on a non-transitory computer-readable storage medium (not shown) of the server system  108  or are divided between the non-transitory computer-readable storage medium of memory  202  and the non-transitory computer-readable storage medium of server system  108 . 
     Peripherals interface  218  is used to couple input and output peripherals of the device to CPU  220  and memory  202 . The one or more processors  220  run or execute various software programs and/or sets of instructions stored in memory  202  to perform various functions for device  200  and to process data. In some embodiments, peripherals interface  218 , CPU  220 , and memory controller  222  are implemented on a single chip, such as chip  204 . In some other embodiments, they are implemented on separate chips. 
     RF (radio frequency) circuitry  208  receives and sends RF signals, also called electromagnetic signals. RF circuitry  208  converts electrical signals to/from electromagnetic signals and communicates with communications networks and other communications devices via the electromagnetic signals. RF circuitry  208  optionally includes well-known circuitry for performing these functions, including but not limited to an antenna system, an RF transceiver, one or more amplifiers, a tuner, one or more oscillators, a digital signal processor, a CODEC chipset, a subscriber identity module (SIM) card, memory, and so forth. RF circuitry  208  optionally communicates with networks, such as the Internet, also referred to as the World Wide Web (WWW), an intranet and/or a wireless network, such as a cellular telephone network, a wireless local area network (LAN) and/or a metropolitan area network (MAN), and other devices by wireless communication. The RF circuitry  208  optionally includes well-known circuitry for detecting near field communication (NFC) fields, such as by a short-range communication radio. The wireless communication optionally uses any of a plurality of communications standards, protocols, and technologies, including but not limited to Global System for Mobile Communications (GSM), Enhanced Data GSM Environment (EDGE), high-speed downlink packet access (HSDPA), high-speed uplink packet access (HSUPA), Evolution, Data-Only (EV-DO), HSPA, HSPA+, Dual-Cell HSPA (DC-HSPDA), long term evolution (LTE), near field communication (NFC), wideband code division multiple access (W-CDMA), code division multiple access (CDMA), time division multiple access (TDMA), Bluetooth, Bluetooth Low Energy (BTLE), Wireless Fidelity (Wi-Fi) (e.g., IEEE 802.11a, IEEE 802.11b, IEEE 802.11g, IEEE 802.11n, and/or IEEE 802.11ac), voice over Internet Protocol (VoIP), Wi-MAX, a protocol for e mail (e.g., Internet message access protocol (IMAP) and/or post office protocol (POP)), instant messaging (e.g., extensible messaging and presence protocol (XMPP), Session Initiation Protocol for Instant Messaging and Presence Leveraging Extensions (SIMPLE), Instant Messaging and Presence Service (IMPS)), and/or Short Message Service (SMS), or any other suitable communication protocol, including communication protocols not yet developed as of the filing date of this document. 
     Audio circuitry  210 , speaker  211 , and microphone  213  provide an audio interface between a user and device  200 . Audio circuitry  210  receives audio data from peripherals interface  218 , converts the audio data to an electrical signal, and transmits the electrical signal to speaker  211 . Speaker  211  converts the electrical signal to human-audible sound waves. Audio circuitry  210  also receives electrical signals converted by microphone  213  from sound waves. Audio circuitry  210  converts the electrical signal to audio data and transmits the audio data to peripherals interface  218  for processing. Audio data are retrieved from and/or transmitted to memory  202  and/or RF circuitry  208  by peripherals interface  218 . In some embodiments, audio circuitry  210  also includes a headset jack (e.g.,  312 ,  FIG.  3   ). The headset jack provides an interface between audio circuitry  210  and removable audio input/output peripherals, such as output-only headphones or a headset with both output (e.g., a headphone for one or both ears) and input (e.g., a microphone). 
     I/O subsystem  206  couples input/output peripherals on device  200 , such as touch screen  212  and other input control devices  216 , to peripherals interface  218 . I/O subsystem  206  optionally includes display controller  256 , optical sensor controller  258 , intensity sensor controller  259 , haptic feedback controller  261 , and one or more input controllers  260  for other input or control devices. The one or more input controllers  260  receive/send electrical signals from/to other input control devices  216 . The other input control devices  216  optionally include physical buttons (e.g., push buttons, rocker buttons, etc.), dials, slider switches, joysticks, click wheels, and so forth. In some alternate embodiments, input controller(s)  260  are, optionally, coupled to any (or none) of the following: a keyboard, an infrared port, a USB port, and a pointer device such as a mouse. The one or more buttons (e.g.,  308 ,  FIG.  3   ) optionally include an up/down button for volume control of speaker  211  and/or microphone  213 . The one or more buttons optionally include a push button (e.g.,  306 ,  FIG.  3   ). 
     A quick press of the push button disengages a lock of touch screen  212  or begin a process that uses gestures on the touch screen to unlock the device, as described in U.S. patent application Ser. No. 11/322,549, “Unlocking a Device by Performing Gestures on an Unlock Image,” filed Dec. 23, 2005, U.S. Pat. No. 7,657,849, which is hereby incorporated by reference in its entirety. A longer press of the push button (e.g.,  306 ) turns power to device  200  on or off. The user is able to customize a functionality of one or more of the buttons. Touch screen  212  is used to implement virtual or soil buttons and one or more soft keyboards. 
     Touch-sensitive display  212  provides an input interface and an output interface between the device and a user. Display controller  256  receives and/or sends electrical signals from/to touch screen  212 . Touch screen  212  displays visual output to the user. The visual output includes graphics, text, icons, video, and any combination thereof (collectively termed “graphics”). In some embodiments, some or all of the visual output correspond to user-interface objects. 
     Touch screen  212  has a touch-sensitive surface, sensor, or set of sensors that accepts input from the user based on haptic and/or tactile contact. Touch screen  212  and display controller  256  (along with any associated modules and/or sets of instructions in memory  202 ) detect contact (and any movement or breaking of the contact) on touch screen  212  and convert the detected contact into interaction with user-interface objects (e.g., one or more soft keys, icons, web pages, or images) that are displayed on touch screen  212 . In an exemplary embodiment, a point of contact between touch screen  212  and the user corresponds to a finger of the user. 
     Touch screen  212  uses LCD (liquid crystal display) technology, LPD (light emitting polymer display) technology, or LED (light emitting diode) technology, although other display technologies may be used in other embodiments. Touch screen  212  and display controller  256  detect contact and any movement or breaking thereof using any of a plurality of touch sensing technologies now known or later developed, including but not limited to capacitive, resistive, infrared, and surface acoustic wave technologies, as well as other proximity sensor arrays or other elements for determining one or more points of contact with touch screen  212 . In an exemplary embodiment, projected mutual capacitance sensing technology is used, such as that found in the iPhone® and iPod Touch® from Apple Inc. of Cupertino, Calif. 
     A touch-sensitive display in some embodiments of touch screen  212  is analogous to the multi-touch sensitive touchpads described in the following U.S. Pat. No. 6,323,846 (Westerman et al.), U.S. Pat. No. 6,570,557 (Westerman et al.), and/or U.S. Pat. No. 6,677,932 (Westerman), and/or U.S. Patent Publication 2002/0015024A1, each of which is hereby incorporated by reference in its entirety. However, touch screen  212  displays visual output from device  200 , whereas touch-sensitive touchpads do not provide visual output. 
     A touch-sensitive display in some embodiments of touch screen  212  is as described in the following applications: (1) U.S. patent application Ser. No. 11/381,313, “Multipoint Touch Surface Controller,” filed May 2, 2006; (2) U.S. patent application Ser. No. 10/840,862, “Multipoint Touchscreen,” filed May 6, 2004; (3) U.S. patent application Ser. No. 10/903,964, “Gestures Touch Sensitive Input Devices,” filed Jul. 30, 2004; (4) U.S. patent application Ser. No. 11/048,264, “Gestures For Touch Sensitive Input Devices,” filed Jan. 31, 2005; (5) U.S. patent application Ser. No. 11/038,590, “Mode-Based Graphical User Interfaces For Touch Sensitive Input Devices,” filed Jan. 18, 2005; (6) U.S. patent application Ser. No. 11/228,758, “Virtual Input Device Placement On A Touch Screen User Interface,” filed Sep. 16, 2005; (7) U.S. patent application Ser. No. 11/228,700, “Operation Of A Computer With A Touch Screen Interface,” filed Sep. 16, 2005; (8) U.S. patent application Ser. No. 11/228,737, “Activating Virtual Keys Of A Touch-Screen Virtual Keyboard,” filed Sep. 16, 2005; and (9) U.S. patent application Ser. No. 11/367,749, “Multi-Functional Hand-Field Device,” filed Mar. 3, 2006. All of these applications are incorporated by reference herein in their entirety. 
     Touch screen  212  has, for example, a video resolution in excess of 100 dpi. In some embodiments, the touch screen has a video resolution of approximately 160 dpi. The user makes contact with touch screen  212  using any suitable object or appendage, such as a stylus, a finger, and so forth. In some embodiments, the user interface is designed to work primarily with finger-based contacts and gestures, which can be less precise than stylus-based input due to the larger area of contact of a finger on the touch screen. In some embodiments, the device translates the rough finger-based input into a precise pointer/cursor position or command for performing the actions desired by the user. 
     In some embodiments, in addition to the touch screen, device  200  includes a touchpad (not shown) for activating or deactivating particular functions. In some embodiments, the touchpad is a touch-sensitive area of the device that, unlike the touch screen, does not display visual output. The touchpad is a touch-sensitive surface that is separate from touch screen  212  or an extension of the touch-sensitive surface formed by the touch screen. 
     Device  200  also includes power system  262  for powering the various components. Power system  262  includes a power management system, one or more power sources (e.g., battery, alternating current (AC)), a recharging system, a power failure detection circuit, a power converter or inverter, a power status indicator (e.g., a light-emitting diode (LED)) and any other components associated with the generation, management and distribution of power in portable devices. 
     Device  200  also includes one or more optical sensors  264 .  FIG.  2 A  shows an optical sensor coupled to optical sensor controller  258  in I/O subsystem  206 . Optical sensor  264  includes charge-coupled device (CCD) or complementary metal-oxide semiconductor (CMOS) phototransistors. Optical sensor  264  receives light from the environment, projected through one or more lenses, and converts the light to data representing an image. In conjunction with imaging module  243  (also called a camera module), optical sensor  264  captures still images or video. In some embodiments, an optical sensor is located on the back of device  200 , opposite touch screen display  212  on the front of the device so that the touch screen display is used as a viewfinder for still and/or video image acquisition. In some embodiments, an optical sensor is located on the front of the device so that the user&#39;s image is obtained for video conferencing while the user views the other video conference participants on the touch screen display. In some embodiments, the position of optical sensor  264  can be changed by the user (e.g., by rotating the lens and the sensor in the device housing) so that a single optical sensor  264  is used along with the touch screen display for both video conferencing and still and/or video image acquisition. 
     Device  200  optionally also includes one or more contact intensity sensors  265 .  FIG.  2 A  shows a contact intensity sensor coupled to intensity sensor controller  259  in I/O subsystem  206 . Contact intensity sensor  265  optionally includes one or more piezoresistive strain gauges, capacitive force sensors, electric force sensors, piezoelectric force sensors, optical force sensors, capacitive touch-sensitive surfaces, or other intensity sensors (e.g., sensors used to measure the force (or pressure) of a contact on a touch-sensitive surface). Contact intensity sensor  265  receives contact intensity information (e.g., pressure information or a proxy for pressure information) from the environment. In some embodiments, at least one contact intensity sensor is collocated with, or proximate to, a touch-sensitive surface (e.g., touch-sensitive display system  212 ). In some embodiments, at least one contact intensity sensor is located on the back of device  200 , opposite touch screen display  212 , which is located on the front of device  200 . 
     Device  200  also includes one or more proximity sensors  266 .  FIG.  2 A  shows proximity sensor  266  coupled to peripherals interface  218 . Alternately, proximity sensor  266  is coupled to input controller  260  in I/O subsystem  206 . Proximity sensor  266  is performed as described in U.S. patent application Ser. No. 11/241,839, “Proximity Detector In Handheld Device”; Ser. No. 11/240,788, “Proximity Detector In Handheld Device”; Ser. No. 11/620,702, “Using Ambient bight Sensor To Augment Proximity Sensor Output”; Ser. No. 11/586,862, “Automated Response To And Sensing Of User Activity In Portable Devices”; and Ser. No. 11/638,251, “Methods And Systems For Automatic Configuration Of Peripherals,” which are hereby incorporated by reference in their entirety. In some embodiments, the proximity sensor turns off and disables touch screen  212  when the multifunction device is placed near the user&#39;s ear (e.g., when the user is making a phone call). 
     Device  200  optionally also includes one or more tactile output generators  267 .  FIG.  2 A  shows a tactile output generator coupled to haptic feedback controller  261  in I/O subsystem  206 . Tactile output generator  267  optionally includes one or more electroacoustic devices such as speakers or other audio components and/or electromechanical devices that convert energy into linear motion such as a motor, solenoid, electroactive polymer, piezoelectric actuator, electrostatic actuator, or other tactile output generating component (e.g., a component that converts electrical signals into tactile outputs on the device). Contact intensity sensor  265  receives tactile feedback generation instructions from haptic feedback module  233  and generates tactile outputs on device  200  that are capable of being sensed by a user of device  200 . In some embodiments, at least one tactile output generator is collocated with, or proximate to, a touch-sensitive surface (e.g., touch-sensitive display system  212 ) and, optionally, generates a tactile output by moving the touch-sensitive surface vertically (e.g., in/out of a surface of device  200 ) or laterally (e.g., back and forth in the same plane as a surface of device  200 ). In some embodiments, at least one tactile output generator sensor is located on the back of device  200 , opposite touch screen display  212 , which is located on the front of device  200 . 
     Device  200  also includes one or more accelerometers  268 .  FIG.  2 A  shows accelerometer  268  coupled to peripherals interface  218 . Alternately, accelerometer  268  is coupled to an input controller  260  in I/O subsystem  206 . Accelerometer  268  performs, for example, as described in U.S. Patent Publication No. 20050190059, “Acceleration-based Theft Detection System for Portable Electronic Devices,” and U.S. Patent Publication No. 20060017692, “Methods And Apparatuses For Operating A Portable Device Based On An Accelerometer,” both of which are incorporated by reference herein in their entirety. In some embodiments, information is displayed on the touch screen display in a portrait view or a landscape view based on an analysis of data received from the one or more accelerometers. Device  200  optionally includes, in addition to accelerometer(s)  268 , a magnetometer (not shown) and a GPS (or GLONASS or other global navigation system) receiver (not shown) for obtaining information concerning the location and orientation (e.g., portrait or landscape) of device  200 . 
     In some embodiments, the software components stored in memory  202  include operating system  226 , communication module (or set of instructions)  228 , contact/motion module (or set of instructions)  230 , graphics module (or set of instructions)  232 , text input module (or set of instructions)  234 , Global Positioning System (GPS) module (or set of instructions)  235 , Digital Assistant Client Module  229 , and applications (or sets of instructions)  236 . Further, memory  202  stores data and models, such as user data and models  231 . Furthermore, in some embodiments, memory  202  ( FIG.  2 A ) or  470  ( FIG.  4   ) stores device/global internal state  257 , as shown in  FIGS.  2 A and  4   . Device/global internal state  257  includes one or more of: active application state, indicating which applications, if any, are currently active; display state, indicating what applications, views or other information occupy various regions of touch screen display  212 ; sensor state, including information obtained from the device&#39;s various sensors and input control devices  216 ; and location information concerning the device&#39;s location and/or attitude. 
     Operating system  226  (e.g., Darwin, RTXC, LINUX, UNIX, OS X, iOS, WINDOWS, or an embedded operating system such as VxWorks) includes various software components and/or drivers for controlling and managing general system tasks (e.g., memory management, storage device control, power management, etc.) and facilitates communication between various hardware and software components. 
     Communication module  228  facilitates communication with other devices over one or more external ports  224  and also includes various software components for handling data received by RF circuitry  208  and/or external port  224 . External port  224  (e.g., Universal Serial Bus (USB), FIREWIRE, etc.) is adapted for coupling directly to other devices or indirectly over a network (e.g., the Internet, wireless LAN, etc). In some embodiments, the external port is a multi-pin (e.g., 30-pin) connector that is the same as, or similar to and/or compatible with, the 30-pin connector used on iPod® (trademark of Apple Inc.) devices. 
     Contact/motion module  230  optionally detects contact with touch screen  212  (in conjunction with display controller  256 ) and other touch-sensitive devices (e.g., a touchpad or physical click wheel). Contact/motion module  230  includes various software components for performing various operations related to detection of contact, such as determining if contact has occurred (e.g., detecting a finger-down event), determining an intensity of the contact (e.g., the force or pressure of the contact or a substitute for the force or pressure of the contact), determining if there is movement of the contact and tracking the movement across the touch-sensitive surface (e.g., detecting one or more finger-dragging events), and determining if the contact has ceased (e.g., detecting a finger-up event or a break in contact). Contact/motion module  230  receives contact data from the touch-sensitive surface. Determining movement of the point of contact, which is represented by a series of contact data, optionally includes determining speed (magnitude), velocity (magnitude and direction), and/or an acceleration (a change in magnitude and/or direction) of the point of contact. These operations are, optionally, applied to single contacts (e.g., one finger contacts) or to multiple simultaneous contacts (e.g., “multitouch”/multiple finger contacts). In some embodiments, contact/motion module  230  and display controller  256  detect contact on a touchpad. 
     In some embodiments, contact/motion module  230  uses a set of one or more intensity thresholds to determine whether an operation has been performed by a user (e.g., to determine whether a user has “clicked” on an icon). In some embodiments, at least a subset of the intensity thresholds are determined in accordance with software parameters (e.g., the intensity thresholds are not determined by the activation thresholds of particular physical actuators and can be adjusted without changing the physical hardware of device  200 ). For example, a mouse “click” threshold of a trackpad or touch screen display can be set to any of a large range of predefined threshold values without changing the trackpad or touch screen display hardware. Additionally, in some implementations, a user of the device is provided with software settings for adjusting one or more of the set of intensity thresholds (e.g., by adjusting individual intensity thresholds and/or by adjusting a plurality of intensity thresholds at once with a system-level click “intensity” parameter). 
     Contact/motion module  230  optionally detects a gesture input by a user. Different gestures on the touch-sensitive surface have different contact patterns (e.g., different motions, timings, and/or intensities of detected contacts). Thus, a gesture is, optionally, detected by detecting a particular contact pattern. For example, detecting a finger tap gesture includes detecting a finger-down event followed by detecting a finger-up (liftoff) event at the same position (or substantially the same position) as the finger-down event (e.g., at the position of an icon). As another example, detecting a finger swipe gesture on the touch-sensitive surface includes detecting a finger-down event followed by detecting one or more finger-dragging events, and subsequently followed by detecting a finger-up (liftoff) event. 
     Graphics module  232  includes various known software components for rendering and displaying graphics on touch screen  212  or other display, including components for changing the visual impact (e.g., brightness, transparency, saturation, contrast, or other visual property) of graphics that are displayed. As used herein, the term “graphics” includes any object that can be displayed to a user, including, without limitation, text, web pages, icons (such as user-interface objects including soft keys), digital images, videos, animations, and the like. 
     In some embodiments, graphics module  232  stores data representing graphics to be used. Each graphic is, optionally, assigned a corresponding code. Graphics module  232  receives, from applications etc., one or more codes specifying graphics to be displayed along with, if necessary, coordinate data and other graphic property data, and then generates screen image data to output to display controller  256 . 
     Haptic feedback module  233  includes various software components for generating instructions used by tactile output generator(s)  267  to produce tactile outputs at one or more locations on device  200  in response to user interactions with device  200 . 
     Text input module  234 , which is, in some examples, a component of graphics module  232 , provides soft keyboards for entering text in various applications (e.g., contacts  237 , email  240 , IM  241 , browser  247 , and any other application that needs text input). 
     GPS module  235  determines the location of the device and provides this information for use in various applications (e.g., to telephone  238  for use in location-based dialing; to camera  243  as picture/video metadata; and to applications that provide location-based services such as weather widgets, local yellow page widgets, and map/navigation widgets). 
     Digital assistant client module  229  includes various client-side digital assistant instructions to provide the client-side functionalities of the digital assistant. For example, digital assistant client module  229  is capable of accepting voice input (e.g., speech input), text input, touch input, and/or gestural input through various user interfaces (e.g., microphone  213 , accelerometer(s)  268 , touch-sensitive display system  212 , optical sensor(s)  264 , other input control devices  216 , etc.) of portable multifunction device  200 . Digital assistant client module  229  is also capable of providing output in audio (e.g., speech output), visual, and/or tactile forms through various output interfaces (e.g., speaker  211 , touch-sensitive display system  212 , tactile output generator(s)  267 , etc.) of portable multifunction device  200 . For example, output is provided as voice, sound, alerts, text messages, menus, graphics, videos, animations, vibrations, and/or combinations of two or more of the above. During operation, digital assistant client module  229  communicates with DA server  106  using RF circuitry  208 . 
     User data and models  231  include various data associated with the user (e.g., user-specific vocabulary data, user preference data, user-specified name pronunciations, data from the user&#39;s electronic address book, to-do lists, shopping lists, etc.) to provide the client-side functionalities of the digital assistant. Further, user data and models  231  include various models (e.g., speech recognition models, statistical language models, natural language processing models, ontology, task flow models, service models, etc.) for processing user input and determining user intent. 
     In some examples, digital assistant client module  229  utilizes the various sensors, subsystems, and peripheral devices of portable multifunction device  200  to gather additional information from the surrounding environment of the portable multifunction device  200  to establish a context associated with a user, the current user interaction, and/or the current user input. In some examples, digital assistant client module  229  provides the contextual information or a subset thereof with the user input to DA server  106  to help inter the user&#39;s intent. In some examples, the digital assistant also uses the contextual information to determine how to prepare and deliver outputs to the user. Contextual information is referred to as context data. 
     In some examples, the contextual information that accompanies the user input includes sensor information, e.g., lighting, ambient noise, ambient temperature, images or videos of the surrounding environment, etc. In some examples, the contextual information can also include the physical state of the device, e.g., device orientation, device location, device temperature, power level, speed, acceleration, motion patterns, cellular signals strength, etc. In some examples, information related to the software state of DA server  106 , e.g., running processes, installed programs, past and present network activities, background services, error logs, resources usage, etc., and of portable multifunction device  200  is provided to DA server  106  as contextual information associated with a user input. 
     In some examples, the digital assistant client module  229  selectively provides information (e.g., user data  231 ) stored on the portable multifunction device  200  in response to requests from DA server  106 . In some examples, digital assistant client module  229  also elicits additional input from the user via a natural language dialogue or other user interfaces upon request by DA server  106 . Digital assistant client module  229  passes the additional input to DA server  106  to help DA server  106  in intent deduction and/or fulfillment of the user&#39;s intent expressed in the user request. 
     A more detailed description of a digital assistant is described below with reference to  FIGS.  7 A-C . It should be recognized that digital assistant client module  229  can include any number of the sub-modules of digital assistant module  726  described below. 
     Applications  236  include the following modules (or sets of instructions), or a subset or superset thereof:
         Contacts module  237  (sometimes called an address book or contact list);   Telephone module  238 ;   Video conference module  239 ;   E-mail client module  240 ;   Instant messaging (IM) module  241 ;   Workout support module  242 ;   Camera module  243  for still and/or video images;   Image management module  244 ;   Video player module;   Music player module;   Browser module  247 ;   Calendar module  248 ;   Widget modules  249 , which includes, in some examples, one or more of: weather widget  249 - 1 , stocks widget  249 - 2 , calculator widget  249 - 3 , alarm clock widget  249 - 4 , dictionary widget  249 - 5 , and other widgets obtained by the user, as well as user-created widgets  249 - 6 ;   Widget creator module  250  for making user-created widgets  249 - 6 ;   Search module  251 ;   Video and music player module  252 , which merges video player module and music player module;   Notes module  253 ;   Map module  254 ; and/or   Online video module  255 .       

     Examples of other applications  236  that are stored in memory  202  include other word processing applications, other image editing applications, drawing applications, presentation applications, JAVA-enabled applications, encryption, digital rights management, voice recognition, and voice replication. 
     In conjunction with touch screen  212 , display controller  256 , contact/motion module  230 , graphics module  232 , and text input module  234 , contacts module  237  are used to manage an address book or contact list (e.g., stored in application internal state  292  of contacts module  237  in memory  202  or memory  470 ), including: adding name(s) to the address book; deleting name(s) from the address book; associating telephone number(s), e-mail address(es), physical address(es) or other information with a name; associating an image with a name; categorizing and sorting names; providing telephone numbers or e-mail addresses to initiate and/or facilitate communications by telephone  238 , video conference module  239 , e-mail  240 , or IM  241 ; and so forth. 
     In conjunction with RF circuitry  208 , audio circuitry  210 , speaker  211 , microphone  213 , touch screen  212 , display controller  256 , contact/motion module  230 , graphics module  232 , and text input module  234 , telephone module  238  are used to enter a sequence of characters corresponding to a telephone number, access one or more telephone numbers in contacts module  237 , modify a telephone number that has been entered, dial a respective telephone number, conduct a conversation, and disconnect or hang up when the conversation is completed. As noted above, the wireless communication uses any of a plurality of communications standards, protocols, and technologies. 
     In conjunction with RF circuitry  208 , audio circuitry  210 , speaker  211 , microphone  213 , touch screen  212 , display controller  256 , optical sensor  264 , optical sensor controller  258 , contact/motion module  230 , graphics module  232 , text input module  234 , contacts module  237 , and telephone module  238 , video conference module  239  includes executable instructions to initiate, conduct, and terminate a video conference between a user and one or more other participants in accordance with user instructions. 
     In conjunction with RF circuitry  208 , touch screen  212 , display controller  256 , contact/motion module  230 , graphics module  232 , and text input module  234 , e-mail client module  240  includes executable instructions to create, send, receive, and manage e-mail in response to user instructions. In conjunction with image management module  244 , e-mail client module  240  makes it very easy to create and send e-mails with still or video images taken with camera module  243 . 
     In conjunction with RF circuitry  208 , touch screen  212 , display controller  256 , contact/motion module  230 , graphics module  232 , and text input module  234 , the instant messaging module  241  includes executable instructions to enter a sequence of characters corresponding to an instant message, to modify previously entered characters, to transmit a respective instant message (for example, using a Short Message Service (SMS) or Multimedia Message Service (MMS) protocol for telephony-based instant messages or using XMPP, SIMPLE, or IMPS for Internet-based instant messages), to receive instant messages, and to view received instant messages. In some embodiments, transmitted and/or received instant messages include graphics, photos, audio files, video files and/or other attachments as are supported in an MMS and/or an Enhanced Messaging Service (EMS). As used herein, “instant messaging” refers to both telephony-based messages (e.g., messages sent using SMS or MMS) and Internet-based messages (e.g., messages sent using XMPP, SIMPLE, or IMPS). 
     In conjunction with RF circuitry  208 , touch screen  212 , display controller  256 , contact/motion module  230 , graphics module  232 , text input module  234 , GPS module  235 , map module  254 , and music player module, workout support module  242  includes executable instructions to create workouts (e.g., with time, distance, and/or calorie burning goals); communicate with workout sensors (sports devices); receive workout sensor data; calibrate sensors used to monitor a workout; select and play music for a workout; and display, store, and transmit workout data. 
     In conjunction with touch screen  212 , display controller  256 , optical sensor(s)  264 , optical sensor controller  258 , contact/motion module  230 , graphics module  232 , and image management module  244 , camera module  243  includes executable instructions to capture still images or video (including a video stream) and store them into memory  202 , modify characteristics of a still image or video, or delete a still image or video from memory  202 . 
     In conjunction with touch screen  212 , display controller  256 , contact/motion module  230 , graphics module  232 , text input module  234 , and camera module  243 , image management module  244  includes executable instructions to arrange, modify (e.g., edit), or otherwise manipulate, label, delete, present (e.g., in a digital slide show or album), and store still and/or video images. 
     In conjunction with RF circuitry  208 , touch screen  212 , display controller  256 , contact/motion module  230 , graphics module  232 , and text input module  234 , browser module  247  includes executable instructions to browse the Internet in accordance with user instructions, including searching, linking to, receiving, and displaying web pages or portions thereof, as well as attachments and other files linked to web pages. 
     In conjunction with RF circuitry  208 , touch screen  212 , display controller  256 , contact/motion module  230 , graphics module  232 , text input module  234 , e-mail client module  240 , and browser module  247 , calendar module  248  includes executable instructions to create, display, modify, and store calendars and data associated with calendars (e.g., calendar entries, to-do lists, etc.) in accordance with user instructions. 
     In conjunction with RF circuitry  208 , touch screen  212 , display controller  256 , contact/motion module  230 , graphics module  232 , text input module  234 , and browser module  247 , widget modules  249  are mini-applications that can be downloaded and used by a user (e.g., weather widget  249 - 1 , stocks widget  249 - 2 , calculator widget  249 - 3 , alarm clock widget  249 - 4 , and dictionary widget  249 - 5 ) or created by the user (e.g., user-created widget  249 - 6 ). In some embodiments, a widget includes an HTML (Hypertext Markup Language) file, a CSS (Cascading Style Sheets) file, and a JavaScript file. In some embodiments, a widget includes an XML (Extensible Markup Language) file and a JavaScript file (e.g., Yahoo! Widgets). 
     In conjunction with RF circuitry  208 , touch screen  212 , display controller  256 , contact/motion module  230 , graphics module  232 , text input module  234 , and browser module  247 , the widget creator module  250  are used by a user to create widgets (e.g., turning a user-specified portion of a web page into a widget). 
     In conjunction with touch screen  212 , display controller  256 , contact/motion module  230 , graphics module  232 , and text input module  234 , search module  251  includes executable instructions to search for text, music, sound, image, video, and/or other files in memory  202  that match one or more search criteria (e.g., one or more user-specified search terms) in accordance with user instructions. 
     In conjunction with touch screen  212 , display controller  256 , contact/motion module  230 , graphics module  232 , audio circuitry  210 , speaker  211 , RF circuitry  208 , and browser module  247 , video and music player module  252  includes executable instructions that allow the user to download and play back recorded music and other sound files stored in one or more file formats, such as MP3 or AAC files, and executable instructions to display, present, or otherwise play back videos (e.g., on touch screen  212  or on an external, connected display via external port  224 ). In some embodiments, device  200  optionally includes the functionality of an MP3 player, such as an iPod (trademark of Apple Inc.). 
     In conjunction with touch screen  212 , display controller  256 , contact/motion module  230 , graphics module  232 , and text input module  234 , notes module  253  includes executable instructions to create and manage notes, to-do lists, and the like in accordance with user instructions. 
     In conjunction with RF circuitry  208 , touch screen  212 , display controller  256 , contact/motion module  230 , graphics module  232 , text input module  234 , GPS module  235 , and browser module  247 , map module  254  are used to receive, display, modify, and store maps and data associated with maps (e.g., driving directions, data on stores and other points of interest at or near a particular location, and other location-based data) in accordance with user instructions. 
     In conjunction with touch screen  212 , display controller  256 , contact/motion module  230 , graphics module  232 , audio circuitry  210 , speaker  211 , RF circuitry  208 , text input module  234 , e-mail client module  240 , and browser module  247 , online video module  255  includes instructions that allow the user to access, browse, receive (e.g., by streaming and/or download), play back (e.g., on the touch screen or on an external, connected display via external port  224 ), send an e-mail with a link to a particular online video, and otherwise manage online videos in one or more file formats, such as H.264. In some embodiments, instant messaging module  241 , rather than e-mail client module  240 , is used to send a link to a particular online video. Additional description of the online video application can be found in U.S. Provisional Patent Application No. 60/936,562, “Portable Multifunction Device, Method, and Graphical User Interface for Playing Online Videos,” filed Jun. 20, 2007, and U.S. patent application Ser. No. 11/968,067, “Portable Multifunction Device, Method, and Graphical User Interface for Playing Online Videos,” filed Dec. 31, 2007, the contents of which are hereby incorporated by reference in their entirety. 
     Each of the above-identified modules and applications corresponds to a set of executable instructions for performing one or more functions described above and the methods described in this application (e.g., the computer-implemented methods and other information processing methods described herein). These modules (e.g., sets of instructions) need not be implemented as separate software programs, procedures, or modules, and thus various subsets of these modules can be combined or otherwise rearranged in various embodiments. For example, video player module can be combined with music player module into a single module (e.g., video and music player module  252 ,  FIG.  2 A ). In some embodiments, memory  202  stores a subset of the modules and data structures identified above. Furthermore, memory  202  stores additional modules and data structures not described above. 
     In some embodiments, device  200  is a device where operation of a predefined set of functions on the device is performed exclusively through a touch screen and/or a touchpad. By using a touch screen and/or a touchpad as the primary input control device for operation of device  200 , the number of physical input control devices (such as push buttons, dials, and the like) on device  200  is reduced. 
     The predefined set of functions that are performed exclusively through a touch screen and/or a touchpad optionally include navigation between user interfaces. In some embodiments, the touchpad, when touched by the user, navigates device  200  to a main, home, or root menu from any user interface that is displayed on device  200 . In such embodiments, a “menu button” is implemented using a touchpad. In some other embodiments, the menu button is a physical push button or other physical input control device instead of a touchpad. 
       FIG.  2 B  is a block diagram illustrating exemplary components for event handling in accordance with some embodiments. In some embodiments, memory  202  ( FIG.  2 A ) or  470  ( FIG.  4   ) includes event sorter  270  (e.g., in operating system  226 ) and a respective application  236 - 1  (e.g., any of the aforementioned applications  237 - 251 ,  255 ,  480 - 490 ). 
     Event sorter  270  receives event information and determines the application  236 - 1  and application view  291  of application  236 - 1  to which to deliver the event information. Event sorter  270  includes event monitor  271  and event dispatcher module  274 . In some embodiments, application  236 - 1  includes application internal state  292 , which indicates the current application views) displayed on touch-sensitive display  212  when the application is active or executing. In some embodiments, device/global internal state  257  is used by event sorter  270  to determine which application(s) is (are) currently active, and application internal state  292  is used by event sorter  270  to determine application views  291  to which to deliver event information. 
     In some embodiments, application internal state  292  includes additional information, such as one or more of: resume information to be used when application  236 - 1  resumes execution, user interface state information that indicates information being displayed or that is ready for display by application  236 - 1 , a state queue for enabling the user to go back to a prior state or view of application  236 - 1 , and a redo/undo queue of previous actions taken by the user. 
     Event monitor  271  receives event information from peripherals interface  218 . Event information includes information about a sub-event (e.g., a user touch on touch-sensitive display  212 , as part of a multi-touch gesture). Peripherals interface  218  transmits information it receives from I/O subsystem  206  or a sensor, such as proximity sensor  266 , accelerometer(s)  268 , and/or microphone  213  (through audio circuitry  210 ). Information that peripherals interface  218  receives from I/O subsystem  206  includes information from touch-sensitive display  212  or a touch-sensitive surface. 
     In some embodiments, event monitor  271  sends requests to the peripherals interface  218  at predetermined intervals. In response, peripherals interface  218  transmits event information. In other embodiments, peripherals interface  218  transmits event information only when there is a significant event (e.g., receiving an input above a predetermined noise threshold and/or for more than a predetermined duration). 
     In some embodiments, event sorter  270  also includes a hit view determination module  272  and/or an active event recognizer determination module  273 . 
     Hit view determination module  272  provides software procedures for determining where a sub-event has taken place within one or more views when touch-sensitive display  212  displays more than one view. Views are made up of controls and other elements that a user can see on the display. 
     Another aspect of the user interface associated with an application is a set of views, sometimes herein called application views or user interface windows, in which information is displayed and touch-based gestures occur. The application views (of a respective application) in which a touch is detected correspond to programmatic levels within a programmatic or view hierarchy of the application. For example, the lowest level view in which a touch is detected is called the hit view, and the set of events that are recognized as proper inputs is determined based, at least in part, on the hit view of the initial touch that begins a touch-based gesture. 
     Hit view determination module  272  receives information related to sub events of a touch-based gesture. When an application has multiple views organized in a hierarchy, hit view determination module  272  identifies a hit view as the lowest view in the hierarchy which should handle the sub-event. In most circumstances, the hit view is the lowest level view in which an initiating sub-event occurs (e.g., the first sub-event in the sequence of sub-events that form an event or potential event). Once the hit view is identified by the hit view determination module  272 , the hit view typically receives all sub-events related to the same touch or input source for which it was identified as the hit view. 
     Active event recognizer determination module  273  determines which view or views within a view hierarchy should receive a particular sequence of sub-events. In some embodiments, active event recognizer determination module  273  determines that only the hit view should receive a particular sequence of sub-events. In other embodiments, active event recognizer determination module  273  determines that all views that include the physical location of a sub-event are actively involved views, and therefore determines that all actively involved views should receive a particular sequence of sub-events. In other embodiments, even if touch sub-events were entirely confined to the area associated with one particular view, views higher in the hierarchy would still remain as actively involved views. 
     Event dispatcher module  274  dispatches the event information to an event recognizer (e.g., event recognizer  280 ). In embodiments including active event recognizer determination module  273 , event dispatcher module  274  delivers the event information to an event recognizer determined by active event recognizer determination module  273 . In some embodiments, event dispatcher module  274  stores in an event queue the event information, which is retrieved by a respective event receiver  282 . 
     In some embodiments, operating system  226  includes event sorter  270 . Alternatively, application  236 - 1  includes event sorter  270 . In yet other embodiments, event sorter  270  is a stand-alone module, or a part of another module stored in memory  202 , such as contact/motion module  230 . 
     In some embodiments, application  236 - 1  includes a plurality of event handlers  290  and one or more application views  291 , each of which includes instructions for handling touch events that occur within a respective view of the application&#39;s user interface. Each application view  291  of the application  236 - 1  includes one or more event recognizers  280 . Typically, a respective application view  291  includes a plurality of event recognizers  280 . In other embodiments, one or more of event recognizers  280  are part of a separate module, such as a user interface kit (not shown) or a higher level object from which application  236 - 1  inherits methods and other properties. In some embodiments, a respective event handler  290  includes one or more of: data updater  276 , object updater  277 , GUI updater  278 , and/or event data  279  received from event sorter  270 . Event handler  290  utilizes or calls data updater  276 , object updater  277 , or GUI updater  278  to update the application internal state  292 . Alternatively, one or more of the application views  291  include one or more respective event handlers  290 . Also, in some embodiments, one or more of data updater  276 , object updater  277 , and GUI updater  278  are included in a respective application view  291 . 
     A respective event recognizer  280  receives event information (e.g., event data  279 ) from event sorter  270  and identifies an event from the event information. Event recognizer  280  includes event receiver  282  and event comparator  284 . In some embodiments, event recognizer  280  also includes at least a subset of: metadata  283 , and event delivery instructions  288  (which include sub-event delivery instructions). 
     Event receiver  282  receives event information from event sorter  270 . The event information includes information about a sub-event, for example, a touch or a touch movement. Depending on the sub-event, the event information also includes additional information, such as location of the sub-event. When the sub-event concerns motion of a touch, the event information also includes speed and direction of the sub-event. In some embodiments, events include rotation of the device from one orientation to another (e.g., from a portrait orientation to a landscape orientation, or vice versa), and the event information includes corresponding information about the current orientation (also called device attitude) of the device. 
     Event comparator  284  compares the event information to predefined event or sub-event definitions and, based on the comparison, determines an event or sub event, or determines or updates the state of an event or sub-event. In some embodiments, event comparator  284  includes event definitions  286 . Event definitions  286  contain definitions of events (e.g., predefined sequences of sub-events), for example, event  1  ( 287 - 1 ), event  2  ( 287 - 2 ), and others. In some embodiments, sub-events in an event ( 287 ) include, for example, touch begin, touch end, touch movement, touch cancellation, and multiple touching. In one example, the definition for event  1  ( 287 - 1 ) is a double tap on a displayed object. The double tap, for example, comprises a first touch (touch begin) on the displayed object for a predetermined phase, a first liftoff (touch end) for a predetermined phase, a second touch (touch begin) on the displayed object for a predetermined phase, and a second liftoff (touch end) for a predetermined phase. In another example, the definition for event  2  ( 287 - 2 ) is a dragging on a displayed object. The dragging, for example, comprises a touch (or contact) on the displayed object for a predetermined phase, a movement of the touch across touch-sensitive display  212 , and liftoff of the touch (touch end). In some embodiments, the event also includes information for one or more associated event handlers  290 . 
     In some embodiments, event definition  287  includes a definition of an event for a respective user-interface object. In some embodiments, event comparator  284  performs a hit test to determine which user-interface object is associated with a sub-event. For example, in an application view in which three user-interface objects are displayed on touch-sensitive display  212 , when a touch is detected on touch-sensitive display  212 , event comparator  284  performs a hit test to determine which of the three user-interface objects is associated with the touch (sub-event). If each displayed object is associated with a respective event handler  290 , the event comparator uses the result of the hit test to determine which event handler  290  should be activated. For example, event comparator  284  selects an event handler associated with the sub-event and the object triggering the hit test. 
     In some embodiments, the definition for a respective event ( 287 ) also includes delayed actions that delay delivery of the event information until after it has been determined whether the sequence of sub-events does or does not correspond to the event recognizer&#39;s event type. 
     When a respective event recognizer  280  determines that the series of sub-events do not match any of the events in event definitions  286 , the respective event recognizer  280  enters an event impossible, event failed, or event ended state, after which it disregards subsequent sub-events of the touch-based gesture. In this situation, other event recognizers, if any, that remain active for the hit view continue to track and process sub-events of an ongoing touch-based gesture. 
     In some embodiments, a respective event recognizer  280  includes metadata  283  with configurable properties, flags, and/or lists that indicate how the event delivery system should perform sub-event delivery to actively involved event recognizers. In some embodiments, metadata  283  includes configurable properties, flags, and/or lists that indicate how event recognizers interact, or are enabled to interact, with one another. In some embodiments, metadata  283  includes configurable properties, flags, and/or lists that indicate whether sub-events are delivered to varying levels in the view or programmatic hierarchy. 
     In some embodiments, a respective event recognizer  280  activates event handler  290  associated with an event when one or more particular sub-events of an event are recognized. In some embodiments, a respective event recognizer  280  delivers event information associated with the event to event handler  290 . Activating an event handler  290  is distinct from sending (and deferred sending) sub-events to a respective hit view. In some embodiments, event recognizer  280  throws a flag associated with the recognized event, and event handler  290  associated with the flag catches the flag and performs a predefined process. 
     In some embodiments, event delivery instructions  288  include sub-event delivery instructions that deliver event information about a sub-event without activating an event handler. Instead, the sub-event delivery instructions deliver event information to event handlers associated with the series of sub-events or to actively involved views. Event handlers associated with the series of sub-events or with actively involved views receive the event information and perform a predetermined process. 
     In some embodiments, data updater  276  creates and updates data used in application  236 - 1 . For example, data updater  276  updates the telephone number used in contacts module  237 , or stores a video file used in video player module. In some embodiments, object updater  277  creates and updates objects used in application  236 - 1 . For example, object updater  277  creates a new user-interface object or updates the position of a user-interface object, GUI updater  278  updates the GUI. For example, GUI updater  278  prepares display information and sends it to graphics module  232  for display on a touch-sensitive display. 
     In some embodiments, event handler(s)  290  includes or has access to data updater  276 , object updater  277 , and GUI updater  278 . In some embodiments, data updater  276 , object updater  277 , and GUI updater  278  are included in a single module of a respective application  236 - 1  or application view  291 . In other embodiments, they are included in two or more software modules. 
     It shall be understood that the foregoing discussion regarding event handling of user touches on touch-sensitive displays also applies to other forms of user inputs to operate multifunction devices  200  with input devices, not all of which are initiated on touch screens. For example, mouse movement and mouse button presses, optionally coordinated with single or multiple keyboard presses or holds: contact movements such as taps, drags, scrolls, etc. on touchpads; pen stylus inputs; movement of the device; oral instructions; detected eye movements; biometric inputs; and/or any combination thereof are optionally utilized as inputs corresponding to sub-events which define an event to be recognized. 
       FIG.  3    illustrates a portable multifunction device  200  having a touch screen  212  in accordance with some embodiments. The touch screen optionally displays one or more graphics within user interface (UI)  300 . In this embodiment, as well as others described below, a user is enabled to select one or more of the graphics by making a gesture on the graphics, for example, with one or more fingers  302  (not drawn to scale in the figure) or one or more styluses  303  (not drawn to scale in the figure). In some embodiments, selection of one or more graphics occurs when the user breaks contact with the one or more graphics. In some embodiments, the gesture optionally includes one or more taps, one or more swipes (from left to right, right to left, upward and/or downward), and/or a rolling of a finger (from right to left, left to right, upward and/or downward) that has made contact with device  200 . In some implementations or circumstances, inadvertent contact with a graphic does not select, the graphic. For example, a swipe gesture that sweeps over an application icon optionally does not select the corresponding application when the gesture corresponding to selection is a tap. 
     Device  200  also includes one or more physical buttons, such as “home” or menu button  304 . As described previously, menu button  304  is used to navigate to any application  236  in a set of applications that is executed on device  200 . Alternatively, in some embodiments, the menu button is implemented as a soft key in a GUI displayed on touch screen  212 . 
     In one embodiment, device  200  includes touch screen  212 , menu button  304 , push button  306  for powering the device on/off and locking the device, volume adjustment button(s)  308 , subscriber identity module (SIM) card slot  310 , headset jack  312 , and docking/charging external port  224 . Push button  306  is, optionally, used to turn the power on/off on the device by depressing the button and holding the button in the depressed state for a predefined time interval; to lock the device by depressing the button and releasing the button before the predefined time interval has elapsed; and/or to unlock the device or initiate an unlock process. In an alternative embodiment, device  200  also accepts verbal input for activation or deactivation of some functions through microphone  213 . Device  200  also, optionally, includes one or more contact intensity sensors  265  for detecting intensity of contacts on touch screen  212  and/or one or more tactile output generators  267  for generating tactile outputs for a user of device  200 . 
       FIG.  4    is a block diagram of an exemplary multifunction device with a display and a touch-sensitive surface in accordance with some embodiments. Device  400  need not be portable. In some embodiments, device  400  is a laptop computer, a desktop computer, a tablet computer, a multimedia player device, a navigation device, an educational device (such as a child&#39;s learning toy), a gaming system, or a control device (e.g., a home or industrial controller). Device  400  typically includes one or more processing units (CPUs)  410 , one or more network or other communications interfaces  460 , memory  470 , and one or more communication buses  420  for interconnecting these components. Communication buses  420  optionally include circuitry (sometimes called a chipset) that interconnects and controls communications between system components. Device  400  includes input/output (I/O) interface  430  comprising display  440 , which is typically a touch screen display. I/O interface  430  also optionally includes a keyboard and/or mouse (or other pointing device)  450  and touchpad  455 , tactile output generator  457  for generating tactile outputs on device  400  (e.g., similar to tactile output generator(s)  267  described above with reference to  FIG.  2 A ), sensors  459  (e.g., optical, acceleration, proximity, touch-sensitive, and/or contact intensity sensors similar to contact intensity sensor(s)  265  described above with reference to  FIG.  2 A ). Memory  470  includes high-speed random access memory, such as DRAM, SRAM, DDR RAM, or other random access solid state memory devices; and optionally includes non-volatile memory, such as one or more magnetic disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid state storage devices. Memory  470  optionally includes one or more storage devices remotely located from CPU(s)  410 . In some embodiments, memory  470  stores programs, modules, and data structures analogous to the programs, modules, and data structures stored in memory  202  of portable multifunction device  200  ( FIG.  2 A ), or a subset thereof. Furthermore, memory  470  optionally stores additional programs, modules, and data structures not present in memory  202  of portable multifunction device  200 . For example, memory  470  of device  400  optionally stores drawing module  480 , presentation module  482 , word processing module  484 , website creation module  486 , disk authoring module  488 , and/or spreadsheet module  490 , while memory  202  of portable multifunction device  200  ( FIG.  2 A ) optionally does not store these modules. 
     Each of the above-identified elements in  FIG.  4    is, in some examples, stored in one or more of the previously mentioned memory devices. Each of the above-identified modules corresponds to a set of instructions for performing a function described above. The above-identified modules or programs (e.g., sets of instructions) need not be implemented as separate software programs, procedures, or modules, and thus various subsets of these modules are combined or otherwise rearranged in various embodiments. In some embodiments, memory  470  stores a subset of the modules and data structures identified above. Furthermore, memory  470  stores additional modules and data structures not described above. 
     Attention is now directed towards embodiments of user interfaces that can be implemented on, for example, portable multifunction device  200 . 
       FIG.  5 A  illustrates an exemplary user interface for a menu of applications on portable multifunction device  200  in accordance with some embodiments. Similar user interfaces are implemented on device  400 . In some embodiments, user interface  500  includes the following elements, or a subset or superset thereof: 
     Signal strength indicator(s)  502  for wireless communication(s), such as cellular and Wi-Fi signals;
         Time  504 ;   Bluetooth indicator  505 ;   Battery status indicator  506 ;   Tray  508  with icons for frequently used applications, such as:
           Icon  516  for telephone module  238 , labeled “Phone,” which optionally includes an indicator  514  of the number of missed calls or voicemail messages;   Icon  518  for e-mail client module  240 , labeled “Mail,” which optionally includes an indicator  510  of the number of unread e-mails;   Icon  520  for browser module  247 , labeled “Browser;” and   Icon  522  for video and music player module  252 , also referred to as iPod (trademark of Apple Inc.) module  252 , labeled “iPod;” and   
           Icons for other applications, such as:
           Icon  524  for IM module  241 , labeled “Messages;”   Icon  526  for calendar module  248 , labeled “Calendar;”   icon  528  for image management module  244 , labeled “Photos;”   Icon  530  for camera module  243 , labeled “Camera;”   Icon  532  for online video module  255 , labeled “Online Video;”   Icon  534  for stocks widget  249 - 2 , labeled “Stocks;”   Icon  536  for map module  254 , labeled “Maps;”   Icon  538  for weather widget  249 - 1 , labeled “Weather;”   Icon  540  for alarm clock widget  249 - 4 , labeled “Clock;”   icon  542  for workout support module  242 , labeled “Workout Support;”   icon  544  for notes module  253 , labeled “Notes;” and   Icon  546  for a settings application or module, labeled “Settings,” which provides access to settings for device  200  and its various applications  236 .   
               

     It should be noted that the icon labels illustrated in  FIG.  5 A  are merely exemplary. For example, icon  522  for video and music player module  252  is optionally labeled “Music” or “Music Player.” Other labels are, optionally, used for various application icons. In some embodiments, a label for a respective application icon includes a name of an application corresponding to the respective application icon. In some embodiments, a label for a particular application icon is distinct from a name of an application corresponding to the particular application icon. 
       FIG.  5 B  illustrates an exemplary user interface on a device (e.g., device  400 ,  FIG.  4   ) with a touch-sensitive surface  551  (e.g., a tablet or touchpad  455 ,  FIG.  4   ) that is separate from the display  550  (e.g., touch screen display  212 ). Device  400  also, optionally, includes one or more contact intensity sensors (e.g., one or more of sensors  457 ) for detecting intensity of contacts on touch-sensitive surface  551  and/or one or more tactile output generators  459  for generating tactile outputs for a user of device  400 . 
     Although some of the examples which follow will be given with reference to inputs on touch screen display  212  (where the touch-sensitive surface and the display are combined), in some embodiments, the device detects inputs on a touch-sensitive surface that is separate from the display, as shown in  FIG.  5 B . In some embodiments, the touch-sensitive surface (e.g.,  551  in  FIG.  5 B ) has a primary axis (e.g.,  552  in  FIG.  5 B ) that corresponds to a primary axis (e.g.,  553  in  FIG.  5 B ) on the display (e.g.,  550 ). In accordance with these embodiments, the device detects contacts (e.g.,  560  and  562  in  FIG.  5 B ) with the touch-sensitive surface  551  at locations that correspond to respective locations on the display (e.g., in  FIG.  5 B,  560    corresponds to  568  and  562  corresponds to  570 ). In this way, user inputs (e.g., contacts  560  and  562 , and movements thereof) detected by the device on the touch-sensitive surface (e.g.,  551  in  FIG.  5 B ) are used by the device to manipulate the user interface on the display (e.g.,  550  in  FIG.  5 B ) of the multifunction device when the touch-sensitive surface is separate from the display. It should be understood that similar methods are, optionally, used for other user interfaces described herein. 
     Additionally, while the following examples are given primarily with reference to finger inputs (e.g., finger contacts, finger tap gestures, finger swipe gestures), it should be understood that, in some embodiments, one or more of the finger inputs are replaced with input from another input device (e.g., a mouse-based input or stylus input). For example, a swipe gesture is, optionally, replaced with a mouse click (e.g., instead of a contact) followed by movement of the cursor along the path of the swipe (e.g., instead of movement of the contact). As another example, a tap gesture is, optionally, replaced with a mouse click while the cursor is located over the location of the tap gesture (e.g., instead of detection of the contact followed by ceasing to detect the contact). Similarly, when multiple user inputs are simultaneously detected, it should be understood that multiple computer mice are, optionally, used simultaneously, or a mouse and finger contacts are, optionally, used simultaneously. 
       FIG.  6 A  illustrates exemplary personal electronic device  600 . Device  600  includes body  602 . In some embodiments, device  600  includes some or all of the features described with respect to devices  200  and  400  (e.g.,  FIGS.  2 A- 4   ). In some embodiments, device  600  has touch-sensitive display screen  604 , hereafter touch screen  604 . Alternatively, or in addition to touch screen  604 , device  600  has a display and a touch-sensitive surface. As with devices  200  and  400 , in some embodiments, touch screen  604  (or the touch-sensitive surface) has one or more intensity sensors for detecting intensity of contacts (e.g., touches) being applied. The one or more intensity sensors of touch screen  604  (or the touch-sensitive surface) provide output data that represents the intensity of touches. The user interface of device  600  responds to touches based on their intensity, meaning that touches of different intensities can invoke different user interface operations on device  600 . 
     Techniques for detecting and processing touch intensity are found, for example, in related applications: International Patent Application Serial No. PCT/US2013/040061, titled “Device, Method, and Graphical User Interface for Displaying User Interface Objects Corresponding to an Application,” filed May 8, 2013, and International Patent Application Serial No. PCT/US2013/069483, titled “Device, Method, and Graphical User interface for Transitioning Between Touch Input to Display Output Relationships,” filed Nov. 11, 2013, each of which is hereby incorporated by reference in their entirety. 
     In some embodiments, device  600  has one or more input mechanisms  606  and  608 . Input mechanisms  606  and  608 , if included, are physical. Examples of physical input mechanisms include push buttons and rotatable mechanisms. In some embodiments, device  600  has one or more attachment mechanisms. Such attachment mechanisms, if included, can permit attachment of device  600  with, for example, hats, eyewear, earrings, necklaces, shirts, jackets, bracelets, watch straps, chains, trousers, belts, shoes, purses, backpacks, and so forth. These attachment mechanisms permit device  600  to be worn by a user. 
       FIG.  6 B  depicts exemplary personal electronic device  600 . In some embodiments, device  600  includes some or all of the components described with respect to  FIGS.  2 A,  2 B, and  4   . Device  600  has bus  612  that operatively couples I/O section  614  with one or more computer processors  616  and memory  618 . I/O section  614  is connected to display  604 , which can have touch-sensitive component  622  and, optionally, touch-intensity sensitive component  624 . In addition, I/O section  614  is connected with communication unit  630  for receiving application and operating system data, using Wi-Fi, Bluetooth, near field communication (NFC), cellular, and/or other wireless communication techniques. Device  600  includes input mechanisms  606  and/or  608 . Input mechanism  606  is a rotatable input device or a depressible and rotatable input device, for example. Input mechanism  608  is a button, in some examples. 
     Input mechanism  608  is a microphone, in some examples. Personal electronic device  600  includes, for example, various sensors, such as GPS sensor  632 , accelerometer  634 , directional sensor  640  (e.g., compass), gyroscope  636 , motion sensor  638 , and/or a combination thereof, all of which are operatively connected to I/O section  614 . 
     Memory  618  of personal electronic device  600  is a non-transitory computer-readable storage medium, for storing computer-executable instructions, which, when executed by one or more computer processors  616 , for example, cause the computer processors to perform the techniques and processes described below. The computer-executable instructions, for example, are also stored and/or transported within any non-transitory computer-readable storage medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. Personal electronic device  600  is not limited to the components and configuration of  FIG.  6 B , but can include other or additional components in multiple configurations. 
     As used here, the term “affordance” refers to a user-interactive graphical user interface object that is, for example, displayed on the display screen of devices  200 ,  400 , and/or  600  ( FIGS.  2 A,  4 , and  6 A -B). For example, an image (e.g., icon), a button, and text (e.g., hyperlink) each constitutes an affordance. 
     As used herein, the term “focus selector” refers to an input element that indicates a current part of a user interface with which a user is interacting. In some implementations that include a cursor or other location marker, the cursor acts as a “focus selector” so that when an input (e.g., a press input) is detected on a touch-sensitive surface (e.g., touchpad  455  in  FIG.  4    or touch-sensitive surface  551  in  FIG.  5 B ) while the cursor is over a particular user interface element (e.g., a button, window, slider or other user interface element), the particular user interface element is adjusted in accordance with the detected input. In some implementations that include a touch screen display (e.g., touch-sensitive display system  212  in  FIG.  2 A  or touch screen  212  in  FIG.  5 A ) that enables direct interaction with user interface elements on the touch screen display, a detected contact on the touch screen acts as a “focus selector” so that when an input (e.g., a press input by the contact) is detected on the touch screen display at a location of a particular user interface element (e.g., a button, window, slider, or other user interface element), the particular user interface element is adjusted in accordance with the detected input. In some implementations, focus is moved from one region of a user interface to another region of the user interface without corresponding movement of a cursor or movement of a contact on a touch screen display (e.g., by using a tab key or arrow keys to move focus from one button to another button); in these implementations, the focus selector moves in accordance with movement of focus between different regions of the user interface. Without regard to the specific form taken by the focus selector, the focus selector is generally the user interface element (or contact on a touch screen display) that is controlled by the user so as to communicate the user&#39;s intended interaction with the user interface (e.g., by indicating, to the device, the element of the user interface with which the user is intending to interact). For example, the location of a focus selector (e.g., a cursor, a contact, or a selection box) over a respective button while a press input is detected on the touch-sensitive surface (e.g., a touchpad or touch screen) will indicate that the user is intending to activate the respective button (as opposed to other user interface elements shown on a display of the device). 
     As used in the specification and claims, the term “characteristic intensity” of a contact refers to a characteristic of the contact based on one or more intensities of the contact. In some embodiments, the characteristic intensity is based on multiple intensity samples. The characteristic intensity is, optionally, based on a predefined number of intensity samples, or a set of intensity samples collected during a predetermined time period (e.g., 0.05, 0.1, 0.2, 0.5, 1, 2, 5, 10 seconds) relative to a predefined event (e.g., after detecting the contact, prior to detecting liftoff of the contact, before or after detecting a start of movement of the contact, prior to detecting an end of the contact, before or after detecting an increase in intensity of the contact, and/or before or after detecting a decrease in intensity of the contact). A characteristic intensity of a contact is, optionally based on one or more of: a maximum value of the intensities of the contact, a mean value of the intensities of the contact, an average value of the intensities of the contact, a top 10 percentile value of the intensities of the contact, a value at the half maximum of the intensities of the contact, a value at the 90 percent maximum of the intensities of the contact, or the like. In some embodiments, the duration of the contact is used in determining the characteristic intensity (e.g., when the characteristic intensity is an average of the intensity of the contact over time). In some embodiments, the characteristic intensity is compared to a set of one or more intensity thresholds to determine whether an operation has been performed by a user. For example, the set of one or more intensity thresholds includes a first intensity threshold and a second intensity threshold. In this example, a contact with a characteristic intensity that does not exceed the first threshold results in a first operation, a contact with a characteristic intensity that exceeds the first intensity threshold and does not exceed the second intensity threshold results in a second operation, and a contact with a characteristic intensity that exceeds the second threshold results in a third operation. In some embodiments, a comparison between the characteristic intensity and one or more thresholds is used to determine whether or not to perform one or more operations (e.g., whether to perform a respective operation or forgo performing the respective operation) rather than being used to determine whether to perform a first operation or a second operation. 
     In some embodiments, a portion of a gesture is identified for purposes of determining a characteristic intensity. For example, a touch-sensitive surface receives a continuous swipe contact transitioning from a start location and reaching an end location, at which point the intensity of the contact increases. In this example, the characteristic intensity of the contact at the end location is based on only a portion of the continuous swipe contact, and not the entire swipe contact (e.g., only the portion of the swipe contact at the end location). In some embodiments, a smoothing algorithm is applied to the intensities of the swipe contact prior to determining the characteristic intensity of the contact. For example, the smoothing algorithm optionally includes one or more of: an unweighted sliding-average smoothing algorithm, a triangular smoothing algorithm, a median filter smoothing algorithm, and/or an exponential smoothing algorithm. In some circumstances, these smoothing algorithms eliminate narrow spikes or dips in the intensities of the swipe contact for purposes of determining a characteristic intensity. 
     The intensity of a contact on the touch-sensitive surface is characterized relative to one or more intensity thresholds, such as a contact-detection intensity threshold, a light press intensity threshold, a deep press intensity threshold, and/or one or more other intensity thresholds. In some embodiments, the light press intensity threshold corresponds to an intensity at which the device will perform operations typically associated with clicking a button of a physical mouse or a trackpad. In some embodiments, the deep press intensity threshold corresponds to an intensity at which the device will perform operations that are different from operations typically associated with clicking a button of a physical mouse or a trackpad. In some embodiments, when a contact is detected with a characteristic intensity below the light press intensity threshold (e.g., and above a nominal contact-detection intensity threshold below which the contact is no longer detected), the device will move a focus selector in accordance with movement of the contact on the touch-sensitive surface without performing an operation associated with the light press intensity threshold or the deep press intensity threshold. Generally, unless otherwise stated, these intensity thresholds are consistent between different sets of user interface figures. 
     An increase of characteristic intensity of the contact from an intensity below the light press intensity threshold to an intensity between the light press intensity threshold and the deep press intensity threshold is sometimes referred to as a “light press” input. An increase of characteristic intensity of the contact from an intensity below the deep press intensity threshold to an intensity above the deep press intensity threshold is sometimes referred to as a “deep press” input. An increase of characteristic intensity of the contact from an intensity below the contact-detection intensity threshold to an intensity between the contact-detection intensity threshold and the light press intensity threshold is sometimes referred to as detecting the contact on the touch-surface. A decrease of characteristic intensity of the contact from an intensity above the contact-detection intensity threshold to an intensity below the contact-detection intensity threshold is sometimes referred to as detecting liftoff of the contact from the touch-surface. In some embodiments, the contact-detection intensity threshold is zero. In some embodiments, the contact-detection intensity threshold is greater than zero. 
     In some embodiments described herein, one or more operations are performed in response to detecting a gesture that includes a respective press input or in response to detecting the respective press input performed with a respective contact (or a plurality of contacts), where the respective press input is detected based at least in part on detecting an increase in intensity of the contact (or plurality of contacts) above a press-input intensity threshold. In some embodiments, the respective operation is performed in response to detecting the increase in intensity of the respective contact above the press-input intensity threshold (e.g., a “down stroke” of the respective press input). In some embodiments, the press input includes an increase in intensity of the respective contact above the press-input intensity threshold and a subsequent decrease in intensity of the contact below the press-input intensity threshold, and the respective operation is performed in response to detecting the subsequent decrease in intensity of the respective contact below the press-input threshold (e.g., an “up stroke” of the respective press input). 
     In some embodiments, the device employs intensity hysteresis to avoid accidental inputs sometimes termed “jitter,” where the device defines or selects a hysteresis intensity threshold with a predefined relationship to the press-input intensity threshold (e.g., the hysteresis intensity threshold is X intensity units lower than the press-input intensity threshold or the hysteresis intensity threshold is 75%, 90%, or some reasonable proportion of the press-input intensity threshold). Thus, in some embodiments, the press input includes an increase in intensity of the respective contact above the press-input intensity threshold and a subsequent decrease in intensity of the contact below the hysteresis intensity threshold that corresponds to the press-input intensity threshold, and the respective operation is performed in response to detecting the subsequent decrease in intensity of the respective contact below the hysteresis intensity threshold (e.g., an “up stroke” of the respective press input). Similarly, in some embodiments, the press input is detected only when the device detects an increase in intensity of the contact from an intensity at or below the hysteresis intensity threshold to an intensity at or above the press-input intensity threshold and, optionally, a subsequent decrease in intensity of the contact to an intensity at or below the hysteresis intensity, and the respective operation is performed in response to detecting the press input (e.g., the increase in intensity of the contact or the decrease in intensity of the contact, depending on the circumstances). 
     For ease of explanation, the descriptions of operations performed in response to a press input associated with a press-input intensity threshold or in response to a gesture including the press input are, optionally, triggered in response to detecting either: an increase in intensity of a contact above the press-input intensity threshold, an increase in intensity of a contact from an intensity below the hysteresis intensity threshold to an intensity above the press-input intensity threshold, a decrease in intensity of the contact below the press-input intensity threshold, and/or a decrease in intensity of the contact below the hysteresis intensity threshold corresponding to the press-input intensity threshold. Additionally, in examples where an operation is described as being performed in response to detecting a decrease in intensity of a contact below the press-input intensity threshold, the operation is, optionally, performed in response to detecting a decrease in intensity of the contact below a hysteresis intensity threshold corresponding to, and lower than, the press-input intensity threshold. 
     3. Digital Assistant System 
       FIG.  7 A  illustrates a block diagram of digital assistant system  700  in accordance with various examples. In some examples, digital assistant system  700  is implemented on a standalone computer system. In some examples, digital assistant system  700  is distributed across multiple computers. In some examples, some of the modules and functions of the digital assistant are divided into a server portion and a client portion, where the client portion resides on one or more user devices (e.g., devices  104 ,  122 ,  200 ,  400 , or  600 ) and communicates with the server portion (e.g., server system  108 ) through one or more networks, e.g., as shown in  FIG.  1   . In some examples, digital assistant system  700  is an implementation of server system  108  (and/or DA server  106 ) shown in  FIG.  1   . It should be noted that digital assistant system  700  is only one example of a digital assistant system, and that digital assistant system  700  can have more or fewer components than shown, can combine two or more components, or can have a different configuration or arrangement of the components. The various components shown in  FIG.  7 A  are implemented in hardware, software instructions for execution by one or more processors, firmware, including one or more signal processing and/or application specific integrated circuits, or a combination thereof. 
     Digital assistant system  700  includes memory  702 , one or more processors  704 , input/output (I/O) interface  706 , and network communications interface  708 . These components can communicate with one another over one or more communication buses or signal lines  710 . 
     In some examples, memory  702  includes a non-transitory computer-readable medium, such as high-speed random access memory and/or a non-volatile computer-readable storage medium (e.g., one or more magnetic disk storage devices, flash memory devices, or other non-volatile solid-state memory devices). 
     In some examples, I/O interface  706  couples input/output devices  716  of digital assistant system  700 , such as displays, keyboards, touch screens, and microphones, to user interface module  722 . I/O interface  706 , in conjunction with user interface module  722 , receives user inputs (e.g., voice input, keyboard inputs, touch inputs, etc.) and processes them accordingly. In some examples, e.g., when the digital assistant is implemented on a standalone user device, digital assistant system  700  includes any of the components and I/O communication interfaces described with respect to devices  200 ,  400 , or  600  in  FIGS.  2 A,  4 ,  6 A -B, respectively. In some examples, digital assistant system  700  represents the server portion of a digital assistant implementation, and can interact with the user through a client-side portion residing on a user device (e.g., devices  104 ,  200 ,  400 , or  600 ). 
     In some examples, the network communications interface  708  includes wired communication port(s)  712  and/or wireless transmission and reception circuitry  714 . The wired communication port(s) receives and send communication signals via one or more wired interfaces, e.g., Ethernet, Universal Serial Bus (USB), FIREWIRE, etc. The wireless circuitry  714  receives and sends RF signals and/or optical signals from/to communications networks and other communications devices. The wireless communications use any of a plurality of communications standards, protocols, and technologies, such as GSM, EDGE, CDMA, TDMA, Bluetooth, Wi-Fi, VoIP, Wi-Max, or any other suitable communication protocol. Network communications interface  708  enables communication between digital assistant system  700  with networks, such as the Internet, an intranet, and/or a wireless network, such as a cellular telephone network, a wireless local area network (LAN), and/or a metropolitan area network (MAN), and other devices. 
     In some examples, memory  702 , or the computer-readable storage media of memory  702 , stores programs, modules, instructions, and data structures including all or a subset of: operating system  718 , communications module  720 , user interface module  722 , one or more applications  724 , and digital assistant module  726 . In particular, memory  702 , or the computer-readable storage media of memory  702 , stores instructions for performing the processes described below. One or more processors  704  execute these programs, modules, and instructions, and reads/writes from/to the data structures. 
     Operating system  718  (e.g., Darwin, RTXC, LINUX, UNIX, iOS, OS X, WINDOWS, or an embedded operating system such as VxWorks) includes various software components and/or drivers for controlling and managing general system tasks (e.g., memory management, storage device control, power management, etc.) and facilitates communications between various hardware, firmware, and software components. 
     Communications module  720  facilitates communications between digital assistant system  700  with other devices over network communications interface  708 . For example, communications module  720  communicates with RF circuitry  208  of electronic devices such as devices  200 ,  400 , and  600  shown in  FIGS.  2 A,  4 ,  6 A -B, respectively. Communications module  720  also includes various components for handling data received by wireless circuitry  714  and/or wired communications port  712 . 
     User interface module  722  receives commands and/or inputs from a user via I/O interface  706  (e.g., from a keyboard, touch screen, pointing device, controller, and/or microphone), and generate user interface objects on a display. User interface module  722  also prepares and delivers outputs (e.g., speech, sound, animation, text, icons, vibrations, haptic feedback, light, etc.) to the user via the I/O interface  706  (e.g., through displays, audio channels, speakers, touch-pads, etc.). 
     Applications  724  include programs and/or modules that are configured to be executed by one or more processors  704 . For example, if the digital assistant system is implemented on a standalone user device, applications  724  include user applications, such as games, a calendar application, a navigation application, or an email application. If digital assistant system  700  is implemented on a server, applications  724  include resource management applications, diagnostic applications, or scheduling applications, for example. 
     Memory  702  also stores digital assistant module  726  (or the server portion of a digital assistant). In some examples, digital assistant module  726  includes the following sub-modules, or a subset or superset thereof: input/output processing module  728 , speech-to-text (STT) processing module  730 , natural language processing module  732 , dialogue flow processing module  734 , task flow processing module  736 , service processing module  738 , and speech synthesis processing module  740 . Each of these modules has access to one or more of the following systems or data and models of the digital assistant module  726 , or a subset or superset thereof: ontology  760 , vocabulary index  744 , user data  748 , task flow models  754 , service models  756 , and ASR systems  758 . 
     In some examples, using the processing modules, data, and models implemented in digital assistant module  726 , the digital assistant can perform at least some of the following: converting speech input into text; identifying a user&#39;s intent expressed in a natural language input received from the user; actively eliciting and obtaining information needed to fully infer the user&#39;s intent (e.g., by disambiguating words, games, intentions, etc.); determining the task flow for fulfilling the inferred intent; and executing the task flow to fulfill the inferred intent. 
     In some examples, as shown in  FIG.  7 B , I/O processing module  728  interacts with the user through I/O devices  716  in  FIG.  7 A  or with a user device (e.g., devices  104 ,  200 ,  400 , or  600 ) through network communications interface  708  in  FIG.  7 A  to obtain user input (e.g., a speech input) and to provide responses (e.g., as speech outputs) to the user input. I/O processing module  728  optionally obtains contextual information associated with the user input from the user device, along with or shortly after the receipt of the user input. The contextual information includes user-specific data, vocabulary, and/or preferences relevant to the user input. In some examples, the contextual information also includes software and hardware states of the user device at the time the user request is received, and/or information related to the surrounding environment of the user at the time that the user request was received. In some examples, I/O processing module  728  also sends follow-up questions to, and receive answers from, the user regarding the user request. When a user request is received by I/O processing module  728  and the user request includes speech input, I/O processing module  728  forwards the speech input to STT processing module  730  (or speech recognizer) for speech-to-text conversions. 
     STT processing module  730  includes one or more ASR systems  758 . The one or more ASR systems  758  can process the speech input that is received through I/O processing module  728  to produce a recognition result. Each ASR system  758  includes a front-end speech pre-processor. The front-end speech pre-processor extracts representative features from the speech input. For example, the front-end speech pre-processor performs a Fourier transform on the speech input to extract spectral features that characterize the speech input as a sequence of representative multi-dimensional vectors. Further, each ASR system  758  includes one or more speech recognition models (e.g., acoustic models and/or language models) and implements one or more speech recognition engines. Examples of speech recognition models include Hidden Markov Models, Gaussian-Mixture Models, Deep Neural Network Models, n-gram language models, and other statistical models. Examples of speech recognition engines include the dynamic time warping based engines and weighted finite-state transducers (WFST) based engines. The one or more speech recognition models and the one or more speech recognition engines are used to process the extracted representative features of the front-end speech pre-processor to produce intermediate recognitions results (e.g., phonemes, phonemic strings, and sub-words), and ultimately, text recognition results (e.g., words, word strings, or sequence of tokens). In some examples, the speech input is processed at least partially by a third-party service or on the user&#39;s device (e.g., device  104 ,  200 ,  400 , or  600 ) to produce the recognition result. Once STT processing module  730  produces recognition results containing a text string (e.g., words, or sequence of words, or sequence of tokens), the recognition result is passed to natural language processing module  732  for intent deduction. In some examples, STT processing module  730  produces multiple candidate text representations of the speech input. Each candidate text representation is a sequence of words or tokens corresponding to the speech input. In some examples, each candidate text representation is associated with a speech recognition confidence score. Based on the speech recognition confidence scores, STT processing module  730  ranks the candidate text representations and provides the n-best (e.g., n highest ranked) candidate text representation(s) to natural language processing module  732  for intent deduction, where n is a predetermined integer greater than zero. For example, in one example, only the highest ranked (n=1) candidate text representation is passed to natural language processing module  732  for intent deduction. In another example, the five highest ranked (n=5) candidate text representations are passed to natural language processing module  732  for intent deduction. 
     More details on the speech-to-text processing are described in U.S. Utility application Ser. No. 13/236,942 for “Consolidating Speech Recognition Results,” filed on Sep. 20, 2011, the entire disclosure of which is incorporated herein by reference. 
     In some examples, STT processing module  730  includes and/or accesses a vocabulary of recognizable words via phonetic alphabet conversion module  731 . Each vocabulary word is associated with one or more candidate pronunciations of the word represented in a speech recognition phonetic alphabet. In particular, the vocabulary of recognizable words includes a word that is associated with a plurality of candidate pronunciations. For example, the vocabulary includes the word “tomato” that is associated with the candidate pronunciations of / / and and / /. Further, vocabulary words are associated with custom candidate pronunciations that are based on previous speech inputs from the user. Such custom candidate pronunciations are stored in STT processing module  730  and are associated with a particular user via the user&#39;s profile on the device. In some examples, the candidate pronunciations for words are determined based on the spelling of the word and one or more linguistic and/or phonetic rules. In some examples, the candidate pronunciations are manually generated, e.g., based on known canonical pronunciations. 
     In some examples, the candidate pronunciations are ranked based on the commonness of the candidate pronunciation. For example, the candidate pronunciation / / is ranked higher than / /, because the former is a more commonly used pronunciation (e.g., among all users, for users in a particular geographical region, or for any other appropriate subset of users). In some examples, candidate pronunciations are ranked based on whether the candidate pronunciation is a custom candidate pronunciation associated with the user. For example, custom candidate pronunciations are ranked higher than canonical candidate pronunciations. This can be useful for recognizing proper nouns having a unique pronunciation that deviates from canonical pronunciation. In some examples, candidate pronunciations are associated with one or more speech characteristics, such as geographic origin, nationality, or ethnicity. For example, the candidate pronunciation / / is associated with the United States, whereas the candidate pronunciation / / is associated with Great Britain. Further, the rank of the candidate pronunciation is based on one or more characteristics (e.g., geographic origin, nationality, ethnicity, etc.) of the user stored in the user&#39;s profile on the device. For example, it can be determined from the user&#39;s profile that the user is associated with the United States. Based on the user being associated with the United States, the candidate pronunciation / / associated with the United States) is ranked higher than the candidate pronunciation / / (associated with Great Britain). In some examples, one of the ranked candidate pronunciations is selected as a predicted pronunciation (e.g., the most likely pronunciation). 
     When a speech input is received, STT processing module  730  is used to determine the phonemes corresponding to the speech input (e.g., using an acoustic model), and then attempt to determine words that match the phonemes (e.g., using a language model). For example, if STT processing module  730  first identifies the sequence of phonemes / / corresponding to a portion of the speech input, it can then determine, based on vocabulary index  744 , that this sequence corresponds to the word “tomato.” 
     In some examples, STT processing module  730  uses approximate matching techniques to determine words in an utterance. Thus, for example, the STT processing module  730  determines that the sequence of phonemes / / corresponds to the word “tomato,” even if that particular sequence of phonemes is not one of the candidate sequence of phonemes for that word. 
     Natural language processing module  732  (“natural language processor”) of the digital assistant takes the n-best candidate text representation(s) (“word sequence(s)” or “token sequence(s)”) generated by STT processing module  730 , and attempts to associate each of the candidate text representations with one or more “actionable intents” recognized by the digital assistant. An “actionable intent” (or “user intent”) represents a task that can be performed by the digital assistant, and can have an associated task flow implemented in task flow models  754 . The associated task flow is a series of programmed actions and steps that the digital assistant takes in order to perform the task. The scope of a digital assistant&#39;s capabilities is dependent on the number and variety of task flows that have been implemented and stored in task flow models  754 , or in other words, on the number and variety of “actionable intents” that the digital assistant recognizes. The effectiveness of the digital assistant, however, also dependents on the assistant&#39;s ability to infer the correct “actionable intent(s)” from the user request expressed in natural language. 
     In some examples, in addition to the sequence of words or tokens obtained from STT processing module  730 , natural language processing module  732  also receives contextual information associated with the user request, e.g., from I/O processing module  728 . The natural language processing module  732  optionally uses the contextual information to clarify, supplement, and/or further define the information contained in the candidate text representations received from STT processing module  730 . The contextual information includes, for example, user preferences, hardware, and/or software states of the user device, sensor information collected before, during, or shortly after the user request, prior interactions (e.g., dialogue) between the digital assistant and the user, and the like. As described herein, contextual information is, in some examples, dynamic, and changes with time, location, content of the dialogue, and other factors. 
     In some examples, the natural language processing is based on, e.g., ontology  760 . Ontology  760  is a hierarchical structure containing many nodes, each node representing either an “actionable intent” or a “property” relevant to one or more of the “actionable intents” or other “properties.” As noted above, an “actionable intent” represents a task that the digital assistant is capable of performing, i.e., it is “actionable” or can be acted on. A “property” represents a parameter associated with an actionable intent or a sub-aspect of another property. A linkage between an actionable intent node and a property node in ontology  760  defines how a parameter represented by the property node pertains to the task represented by the actionable intent node. 
     In some examples, ontology  760  is made up of actionable intent nodes and property nodes. Within ontology  760 , each actionable intent node is linked to one or more property nodes either directly or through one or more intermediate property nodes. Similarly, each property node is linked to one or more actionable intent nodes either directly or through one or more intermediate property nodes. For example, as shown in  FIG.  7 C , ontology  760  includes a “restaurant reservation” node (i.e., an actionable intent node). Property nodes “restaurant,” “date/time” (for the reservation), and “party size” are each directly linked to the actionable intent node (i.e., the “restaurant reservation” node). 
     In addition, property nodes “cuisine,” “price range,” “phone number,” and “location” are sub-nodes of the property node “restaurant,” and are each linked to the “restaurant reservation” node (i.e., the actionable intent node) through the intermediate property node “restaurant.” For another example, as shown in  FIG.  7 C , ontology  760  also includes a “set reminder” node (i.e., another actionable intent node). Property nodes “date/time” (for setting the reminder) and “subject” (for the reminder) are each linked to the “set reminder” node. Since the property “date/time” is relevant to both the task of making a restaurant reservation and the task of setting a reminder, the property node “date/time” is linked to both the “restaurant reservation” node and the “set reminder” node in ontology  760 . 
     An actionable intent node, along with its linked property nodes, is described as a “domain.” In the present discussion, each domain is associated with a respective actionable intent, and refers to the group of nodes (and the relationships there between) associated with the particular actionable intent. For example, ontology  760  shown in  FIG.  7 C  includes an example of restaurant reservation domain  762  and an example of reminder domain  764  within ontology  760 . The restaurant reservation domain includes the actionable intent node “restaurant reservation,” property nodes “restaurant,” “date/time,” and “party size,” and sub-property nodes “cuisine,” “price range,” “phone number,” and “location.” Reminder domain  764  includes the actionable intent node “set reminder,” and property nodes “subject” and “date/time.” In some examples, ontology  760  is made up of many domains. Each domain shares one or more property nodes with one or more other domains. For example, the “date/time” property node is associated with many different domains (e.g., a scheduling domain, a travel reservation domain, a movie ticket domain, etc.), in addition to restaurant reservation domain  762  and reminder domain  764 . 
     While  FIG.  7 C  illustrates two example domains within ontology  760 , other domains include, for example, “find a movie,” “initiate a phone call,” “find directions,” “schedule a meeting,” “send a message,” and “provide an answer to a question,” “read a list,” “providing navigation instructions,” “provide instructions for a task” and so on. A “send a message” domain is associated with a “send a message” actionable intent node, and further includes property nodes such as “recipient(s),” “message type,” and “message body.” The property node “recipient” is further defined, for example, by the sub-property nodes such as “recipient name” and “message address.” 
     In some examples, ontology  760  includes all the domains (and hence actionable intents) that the digital assistant is capable of understanding and acting upon. In some examples, ontology  760  is modified, such as by adding or removing entire domains or nodes, or by modifying relationships between the nodes within the ontology  760 . 
     In some examples, nodes associated with multiple related actionable intents are clustered under a “super domain” in ontology  760 . For example, a “travel” super-domain includes a cluster of property nodes and actionable intent nodes related to travel. The actionable intent nodes related to travel includes “airline reservation,” “hotel reservation,” “car rental,” “get directions,” “find points of interest,” and so on. The actionable intent nodes under the same super domain the “travel” super domain) have many property nodes in common. For example, the actionable intent nodes for “airline reservation,” “hotel reservation,” “car rental,” “get directions,” and “find points of interest” share one or more of the property nodes “start location,” “destination,” “departure date/time,” “arrival date/time,” and “party size.” 
     In some examples, each node in ontology  760  is associated with a set of words and/or phrases that are relevant to the property or actionable intent represented by the node. The respective set of words and/or phrases associated with each node are the so-called “vocabulary” associated with the node. The respective set of words and/or phrases associated with each node are stored in vocabulary index  744  in association with the property or actionable intent represented by the node. For example, returning to  FIG.  7 B , the vocabulary associated with the node for the property of “restaurant” includes words such as “food,” “drinks,” “cuisine,” “hungry,” “eat,” “pizza,” “fast food,” “meal,” and so on. For another example, the vocabulary associated with the node for the actionable intent of “initiate a phone call” includes words and phrases such as “call,” “phone,” “dial,” “ring,” “call this number,” “make a call to,” and so on. The vocabulary index  744  optionally includes words and phrases in different languages. 
     Natural language processing module  732  receives the candidate text representations (e.g., text string(s) or token sequence(s)) from STT processing module  730 , and for each candidate representation, determines what nodes are implicated by the words in the candidate text representation. In some examples, if a word or phrase in the candidate text representation is found to be associated with one or more nodes in ontology  760  (via vocabulary index  744 ), the word or phrase “triggers” or “activates” those nodes. Based on the quantity and/or relative importance of the activated nodes, natural language processing module  732  selects one of the actionable intents as the task that the user intended the digital assistant to perform. In some examples, the domain that has the most “triggered” nodes is selected. In some examples, the domain having the highest confidence value (e.g., based on the relative importance of its various triggered nodes) is selected. In some examples, the domain is selected based on a combination of the number and the importance of the triggered nodes. In some examples, additional factors are considered in selecting the node as well, such as whether the digital assistant has previously correctly interpreted a similar request from a user. 
     User data  748  includes user-specific information, such as user-specific vocabulary, user preferences, user address, user&#39;s default and secondary languages, user&#39;s contact list, and other short-term or long-term information for each user. In some examples, natural language processing module  732  uses the user-specific information to supplement the information contained in the user input to further define the user intent. For example, for a user request “invite my friends to my birthday party,” natural language processing module  732  is able to access user data  748  to determine who the “friends” are and when and where the “birthday party” would be held, rather than requiring the user to provide such information explicitly in his/her request. 
     It should be recognized that in some examples, natural language processing module  732  is implemented using one or more machine learning mechanisms (e.g., neural networks). In particular, the one or more machine learning mechanisms are configured to receive a candidate text representation and contextual information associated with the candidate text representation. Based on the candidate text representation and the associated contextual information, the one or more machine learning mechanisms are configured to determine intent confidence scores over a set of candidate actionable intents. Natural language processing module  732  can select one or more candidate actionable intents from the set of candidate actionable intents based on the determined intent confidence scores. In some examples, an ontology (e.g., ontology  760 ) is also used to select the one or more candidate actionable intents from the set of candidate actionable intents. 
     Other details of searching an ontology based on a token string are described in U.S. Utility application Ser. No. 12/341,743 for “Method and Apparatus for Searching Using An Active Ontology,” filed Dec. 22, 2008, the entire disclosure of which is incorporated herein by reference. 
     In some examples, once natural language processing module  732  identifies an actionable intent (or domain) based on the user request, natural language processing module  732  generates a structured query to represent the identified actionable intent. In some examples, the structured query includes parameters for one or more nodes within the domain for the actionable intent, and at least some of the parameters are populated with the specific information and requirements specified in the user request. For example, the user says “Make me a dinner reservation at a sushi place at 7.” In this case, natural language processing module  732  is able to correctly identify the actionable intent to be “restaurant reservation” based on the user input. According to the ontology, a structured query for a “restaurant reservation” domain includes parameters such as {Cuisine}, {Time}, {Date}, {Party Size}, and the like. In some examples, based on the speech input and the text derived from the speech input using STT processing module  730 , natural language processing module  732  generates a partial structured query for the restaurant reservation domain, where the partial structured query includes the parameters {Cuisine=“Sushi”} and {Time=“7pm”}. However, in this example, the user&#39;s utterance contains insufficient information to complete the structured query associated with the domain. Therefore, other necessary parameters such as {Party Size} and {Date} are not specified in the structured query based on the information currently available. In some examples, natural language processing module  732  populates some parameters of the structured query with received contextual information. For example, in some examples, if the user requested a sushi restaurant “near me,” natural language processing module  732  populates a {location} parameter in the structured query with GPS coordinates from the user device. 
     In some examples, natural language processing module  732  identifies multiple candidate actionable intents for each candidate text representation received from STT processing module  730 . Further, in some examples, a respective structured query (partial or complete) is generated for each identified candidate actionable intent. Natural language processing module  732  determines an intent confidence score for each candidate actionable intent and ranks the candidate actionable intents based on the intent confidence scores. In some examples, natural language processing module  732  passes the generated structured query (or queries), including any completed parameters, to task flow processing module  736  (“task flow processor”). In some examples, the structured query (or queries) for the m-best (e.g., m highest ranked) candidate actionable intents are provided to task flow processing module  736 , where m is a predetermined integer greater than zero. In some examples, the structured query (or queries) for the m-best candidate actionable intents are provided to task flow processing module  736  with the corresponding candidate text representation(s). 
     Other details of inferring a user intent based on multiple candidate actionable intents determined from multiple candidate text representations of a speech input are described in U.S. Utility application Ser. No. 14/298,725 for “System and Method for Inferring User Intent From Speech Inputs,” filed Jun. 6, 2014, the entire disclosure of which is incorporated herein by reference. 
     Task flow processing module  736  is configured to receive the structured query (or queries) from natural language processing module  732 , complete the structured query, if necessary, and perform the actions required to “complete” the user&#39;s ultimate request. In some examples, the various procedures necessary to complete these tasks are provided in task flow models  754 . In some examples, task flow models  754  include procedures for obtaining additional information from the user and task flows for performing actions associated with the actionable intent. 
     As described above, in order to complete a structured query, task flow processing module  736  needs to initiate additional dialogue with the user in order to obtain additional information, and/or disambiguate potentially ambiguous utterances. When such interactions are necessary, task flow processing module  736  invokes dialogue flow processing module  734  to engage in a dialogue with the user. In some examples, dialogue flow processing module  734  determines how (and/or when) to ask the user for the additional information and receives and processes the user responses. The questions are provided to and answers are received from the users through I/O processing module  728 . In some examples, dialogue flow processing module  734  presents dialogue output to the user via audio and/or visual output, and receives input from the user via spoken or physical (e.g., clicking) responses. Continuing with the example above, when task flow processing module  736  invokes dialogue flow processing module  734  to determine the “party size” and “date” information for the structured query associated with the domain “restaurant reservation,” dialogue flow processing module  734  generates questions such as “For how many people?” and “On which day?” to pass to the user. Once answers are received from the user, dialogue flow processing module  734  then populates the structured query with the missing information, or pass the information to task flow processing module  736  to complete the missing information from the structured query. 
     Once task flow processing module  736  has completed the structured query for an actionable intent, task flow processing module  736  proceeds to perform the ultimate task associated with the actionable intent. Accordingly, task flow processing module  736  executes the steps and instructions in the task flow model according to the specific parameters contained in the structured query. For example, the task flow model for the actionable intent of “restaurant reservation” includes steps and instructions for contacting a restaurant and actually requesting a reservation for a particular party size at a particular time. For example, using a structured query such as: {restaurant reservation, restaurant=ABC Café, date=3/12/2012, time=7pm, party size=5}, task flow processing module  736  performs the steps of: (1) logging onto a server of the ABC Café or a restaurant reservation system such as OPENTABLE®, (2) entering the date, time, and party size information in a form on the website, (3) submitting the form, and (4) making a calendar entry for the reservation in the user&#39;s calendar. 
     In some examples, task flow processing module  736  employs the assistance of service processing module  738  (“service processing module”) to complete a task requested in the user input or to provide an informational answer requested in the user input. For example, service processing module  738  acts on behalf of task flow processing module  736  to make a phone call, set a calendar entry, invoke a map search, invoke or interact with other user applications installed on the user device, and invoke or interact with third-party services (e.g., a restaurant reservation portal, a social networking website, a banking portal, etc.). In some examples, the protocols and application programming interfaces (API) required by each service are specified by a respective service model among service models  756 . Service processing module  738  accesses the appropriate service model for a service and generates requests for the service in accordance with the protocols and APIs required by the service according to the service model. 
     For example, if a restaurant has enabled an online reservation service, the restaurant submits a service model specifying the necessary parameters for making a reservation and the APIs for communicating the values of the necessary parameter to the online reservation service. When requested by task flow processing module  736 , service processing module  738  establishes a network connection with the online reservation service using the web address stored in the service model, and sends the necessary parameters of the reservation (e.g., time, date, party size) to the online reservation interface in a format according to the API of the online reservation service. 
     In some examples, natural language processing module  732 , dialogue flow processing module  734 , and task flow processing module  736  are used collectively and iteratively to infer and define the user&#39;s intent, obtain information to further clarify and refine the user intent, and finally generate a response (i.e., an output to the user, or the completion of a task) to fulfill the user&#39;s intent. The generated response is a dialogue response to the speech input that at least partially fulfills the user&#39;s intent. Further, in some examples, the generated response is output as a speech output. In these examples, the generated response is sent to speech synthesis processing module  740  (e.g., speech synthesizer) where it can be processed to synthesize the dialogue response in speech form. In yet other examples, the generated response is data content relevant to satisfying a user request in the speech input. 
     In examples where task flow processing module  736  receives multiple structured queries from natural language processing module  732 , task flow processing module  736  initially processes the first structured query of the received structured queries to attempt to complete the first structured query and/or execute one or more tasks or actions represented by the first structured query. In some examples, the first structured query corresponds to the highest ranked actionable intent. In other examples, the first structured query is selected from the received structured queries based on a combination of the corresponding speech recognition confidence scores and the corresponding intent confidence scores. In some examples, if task flow processing module  736  encounters an error during processing of the first structured query (e.g., due to an inability to determine a necessary parameter), the task flow processing module  736  can proceed to select and process a second structured query of the received structured queries that corresponds to a lower ranked actionable intent. The second structured query is selected, for example, based on the speech recognition confidence score of the corresponding candidate text representation, the intent confidence score of the corresponding candidate actionable intent, a missing necessary parameter in the first structured query, or any combination thereof. 
     Speech synthesis processing module  740  is configured to synthesize speech outputs for presentation to the user. Speech synthesis processing module  740  synthesizes speech outputs based on text provided by the digital assistant. For example, the generated dialogue response is in the form of a text string. Speech synthesis processing module  740  converts the text string to an audible speech output. Speech synthesis processing module  740  uses any appropriate speech synthesis technique in order to generate speech outputs from text, including, but not limited, to concatenative synthesis, unit selection synthesis, diphone synthesis, domain-specific synthesis, dormant synthesis, articulatory synthesis, hidden Markov model (HMM) based synthesis, and sinewave synthesis. In some examples, speech synthesis processing module  740  is configured to synthesize individual words based on phonemic strings corresponding to the words. For example, a phonemic string is associated with a word in the generated dialogue response. The phonemic string is stored in metadata associated with the word. Speech synthesis processing module  740  is configured to directly process the phonemic string in the metadata to synthesize the word in speech form. 
     In some examples, instead of (or in addition to) using speech synthesis processing module  740 , speech synthesis is performed on a remote device (e.g., the server system  108 ), and the synthesized speech is sent to the user device for output to the user. For example, this can occur in some implementations where outputs for a digital assistant are generated at a server system. And because server systems generally have more processing power or resources than a user device, it is possible to obtain higher quality speech outputs than would be practical with client-side synthesis. 
     Additional details on digital assistants can be found in the U.S. Utility application Ser. No. 12/987,982, entitled “Intelligent Automated Assistant,” filed Jan. 10, 2011, and U.S. Utility application Ser. No. 13/251,088, entitled “Generating and Processing Task Items That Represent Tasks to Perform,” filed Sep. 30, 2011, the entire disclosures of which are incorporated herein by reference. 
     4. Process for User Identification Using Headphones 
       FIGS.  8 A- 8 C and  9    illustrate systems for user identification using headphones. For example, as shown in  FIG.  8 A , various electronic devices, such as devices  804  and  806 , may include any device described herein, including but not limited to devices  104 ,  200 ,  400 , and  600  ( FIGS.  1 ,  2 A,  4 , and  6 A -B). Thus, it will be appreciated that the electronic devices depicted in  FIGS.  8 A- 8 C and  9    may correspond to a user device of any type, such as a phone, laptop computer, desktop computer, tablet, wearable device (e.g., smart watch), and the like. Furthermore, the processes described herein may be performed by a server with information delivered to and from the device, performed on the device, or a combination thereof. 
     With reference to  FIG.  8 A , a user  802  may utilize various electronic devices, such as one or more wearable devices. For instance, user  802  may utilize wireless headphones  804  and electronic watch  806 . In some examples, wireless headphones  804  may be associated with a charging component, such as a charging case  808 . The user may also utilize a mobile device  810 . Each of devices  804 ,  806 ,  808 , and  810  may be communicatively coupled, such that various functions on each device may be at least in part accessible via one or more of the other devices. For example, the user may receive a message at mobile phone  810  (e.g., a text message, an e-mail message, etc.). The received message may be accessible via electronic watch  806  (e.g., the user may view the message via electronic watch  806 ) and wireless headphones  804  (e.g., an audible representation of the message may be provided via wireless headphones  804 ). In some examples, user  802  may have been previously authenticated using electronic watch  806 . For example, user  802  may input authentication credentials to electronic watch  806  (e.g., a passcode, a facial identification, a voice identification, and the like), such that the authentication credentials are compared to reference credentials. Upon successful authentication, the user may utilize electronic watch  806  to perform various functions, such as sending and receiving messages, conducting phone calls, tracking exercises, and the like. 
     In some examples, movement information may be detected corresponding to movement of the various electronic devices. The movement information may be detected at a mobile device  810 , for example. Specifically, movement information corresponding to movement of wireless headphones  804  is detected. As depicted in  FIG.  8 A , user  802  may reach out and begin to grasp wireless headphones  804 . Referring now to  FIG.  8 B , user  802  may begin to move the wireless headphones off of a surface (e.g., a tabletop), for example. Alternatively, wireless headphones  804  may be charging inside of charging case  808 , such that the user opens charging case  808  and removes wireless headphones  804  from charging case  808 . In some examples, one or more signals may indicate the beginning of movement of electronic device  804 . In particular, wireless headphones  804  may include one or more accelerometers or other motion sensors, such that various signals including acceleration values (e.g., acceleration values along various axes) are produced by the accelerometer(s) based on movement of wireless headphones  804 . A signal may also be generated by charging case  808  and/or wireless headphones  804  when the user removes wireless headphones  804  from charging case  808 . Movement information corresponding to movement of electronic watch  806  may also be detected. Electronic watch  806  may include one or more accelerometers or other motion sensors, such that various signals including acceleration values (e.g., acceleration values along various axes) are produced by the accelerometer(s) based on movement of electronic watch  806 . 
     In some examples, a determination is made whether movement information of the wireless headphones  804  corresponds to a first movement profile. The first movement profile may include a known movement pattern of a first device type, such as wireless headphones. For example, the first movement profile may include various positions and/or orientations along a movement path, and a movement pattern between the various positions and/or orientations along the movement path. A first position of the movement profile may correspond to a resting position of wireless headphones, such as a position and/or orientation associated with the headphones being outside of a charging case and resting on a surface (e.g., a tabletop). For example, various signals (e.g., from one or more wireless headphone components such as accelerometers, gyroscopes, etc.) may be provided from wireless headphones  804  to indicate that wireless headphones  804  are not moving (e.g., as depicted in  FIG.  8 A ). The signals may further indicate that wireless headphones  804  are associated with a position and/or orientation consistent with being placed on surface (e.g., the headphones are stationary). The first position may alternatively be determined based on an indication that the wireless headphones are charging within a charging case. 
     The first movement profile may include a movement pattern from the first position to a second position. In particular, the movement pattern may include expected acceleration from a plurality of axes associated with movement of wireless headphones between one or more positions. The expected acceleration may correspond to acceleration between the first resting position and a second position corresponding to an “in-ear” position as discussed with respect to  FIG.  8 C . In particular, the expected acceleration of the first movement profile may include one or more expected acceleration values along a X-axis in three dimensional space, one or more expected acceleration values along a Y-axis in three dimensional space, and one or more expected acceleration values along a Z-axis in three dimensional space. For example, the expected acceleration may correspond to the typical movement of wireless headphones when a user grasps the headphones from a first position and places the headphones within the user&#39;s ear at a second position. In some examples, the first movement profile and associated expected acceleration values may initially be based on data from a plurality of users (e.g., a default movement profile). Based on a typical movement profile of a specific user, the first movement profile may be dynamically updated from the initial profile based on the typical movements of the user, such as the movement of wireless headphones  804  as depicted in  FIG.  8 B . 
     Referring to  FIG.  8 C , the first movement profile may additionally include a second position of the first device type, such as a final resting position. For example, the second position may correspond to an “in-ear” position of wireless headphones. In particular, the “in-ear” position may be determined based on various signals indicating that wireless headphones are aligned or have otherwise been placed within a listening position in the user&#39;s ear. The second position may be determined by feedback provided from one or more optical sensors within the wireless headphones, and/or based on acceleration signals received from the wireless headphones. For example, optical sensors of wireless headphones  804  may provide one or more signals indicating that the headphones have been placed in an ear of the user (e.g., the optical sensors may detect change in lighting consistent with being placed in the user&#39;s ear). In some examples, signals may further indicate that wireless headphones  804  are associated with an orientation consistent with being placed in the user&#39;s ear. 
     In some examples, a determination is made whether movement information of the electronic watch  806  corresponds to a second movement profile. The second movement profile may include a known movement pattern of a second device type, such as an electronic watch, For example, the first movement profile may include various positions and/or orientations along a movement path, and a movement pattern between the various positions and/or orientations along the movement path. A first position of the movement profile may correspond to a position consistent with a user reaching out to grasp an item (e.g., a wireless headphone). For example, referring back to  FIG.  8 A , various signals (e.g., from one or more electronic watch components such as accelerometers, gyroscopes, etc.) may be provided from electronic watch  806 , wherein the signals are consistent with a user reaching to grasp an item such as wireless headphones  804 . The signals may include specific acceleration values (e.g., values indicating the electronic watch movement beginning to move after a brief pause in movement) and/or specific orientation values (e.g., values indicating specific movements of the user&#39;s wrist). 
     The second movement profile may include a movement pattern from the first position to a second position. In particular, the movement pattern may include expected acceleration from a plurality of axes associated with an electronic watch. The expected acceleration may correspond to acceleration between the first grasping position and a second position corresponding a position proximate to a user&#39;s ear, as discussed with respect to  FIG.  8 C . In particular, the expected acceleration of the second movement profile may include one or more expected acceleration values along a X-axis in three dimensional space, one or more expected acceleration values along a Y-axis in three dimensional space, and one or more expected acceleration values along a Z-axis in three dimensional space. The expected acceleration may correspond to the typical movement of an electronic watch when a user grasps an item (e.g., wireless headphones) from a first position and places the item at a second position (e.g., within the user&#39;s ear). The second movement profile may further include various changes in orientation of the electronic watch as the user moves the electronic watch from the first position to the second position. For example, the movement profile may include values consistent with gradual adjustment of the orientation of a user&#39;s wrist, such as a specific wrist rotation in order to properly place headphones in the user&#39;s ear. In some examples, the second movement profile and associated movement values may initially be based on data from a plurality of users, wherein the second movement profile may be dynamically updated from the initial profile based on the typical movements of a respective user, such as the movement of electronic watch  806  as depicted in  FIG.  8 B . 
     Referring to  FIG.  8 C , the second movement profile may additionally include a second final position of the second device type. For example, the second position may correspond a “raised-wrist” position of the electronic watch. In particular, the “raised-wrist” position may be determined based on various signals indicating that the electronic watch has moved upwards and stopped at known position. In general, the electronic watch may be associated with various known positions, such as resting at a user&#39;s side, resting on a surface, raised above a waist or head of the user, and the like. In particular, the known position may correspond to a position near the head of the user (e.g., close to a user&#39;s ear). The second position may be determined by feedback provided from one or more sensors within electronic watch  806 , and/or based on acceleration signals received from electronic watch  806 . For example, the signals may be provided from electronic watch  806  to indicate that electronic watch  806  is proximate to an ear of the user. The signals may further indicate that electronic watch  806  is associated with an orientation consistent with the surface of electronic watch  806  facing outwards as depicted in  FIG.  8 C  (e.g., facing away from the user to a certain degree). 
     Detecting movement information based on whether the movement information corresponds to a movement profile may occur concurrently with the movement. In some examples, the detection may occur once the movement of the respective device has reached a specific position (e.g., the second position of wireless headphones  804  or the second position of electronic watch  806 ). Specifically, the first movement information and/or second movement information may be determined based on a root square sum of a respective plurality of signals. For example, wireless headphones  804  may provide various acceleration signals corresponding to movement of wireless headphones  804  from the first position to the second position as depicted in  FIGS.  8 A- 8 C . The acceleration signals may correspond to acceleration of wireless headphones  804  along the X-axis, Y-axis, and Z-axis of the physical environment, respectively. The root square sum of the various acceleration signals from wireless headphones  804  may be computed in order to obtain the first movement information. Similarly, electronic watch  806  may provide various acceleration signals corresponding to movement of electronic watch  806  from the first position to the second position as depicted in  FIGS.  8 A- 8 C . The acceleration signals may correspond to acceleration of electronic watch  806  along the X-axis, Y-axis, and Z-axis of the physical environment, respectively. The root square sum of the various acceleration signals from electronic watch  806  may be computed in order to obtain the second movement information. 
     Once the first movement information and second movement information is detected, a similarity score may be determined. In particular, a similarity score is determined based on the first movement information and the second movement information. In some examples, the determination that the first movement information and second movement information correspond to respective movement patterns is a prerequisite to determining the similarity score. For example, a user of electronic watch  806  may grasp wireless headphones  804  and place wireless headphones  804  in an ear of the user (as depicted in  FIGS.  8 A- 8 C ). In this case, the first movement information may be determined to correspond to the known movement pattern of the first device type (e.g., movement from a resting position to a user&#39;s ear). Alternatively, a second user (e.g., a user not associated with electronic watch  806  and/or a user not wearing electronic watch  806 ) may grasp wireless headphones  804  and place wireless headphones  804  in the ear of the second user. While the second user is handling wireless headphones  804 , the user wearing electronic watch  806  may be standing still with the electronic watch  806  at their side, or may be performing another movement with electronic watch  806  (e.g., typing on a keyboard). In this case, the second movement information may be determined to not correspond to the known movement pattern of the second device type, for example, based at least in on the second movement information including little to no movement. As a result, the similarity score is not determined until the first movement information and second movement information are detected and determined as corresponding to the respective movement patterns. 
     The similarity score may generally represent a similarity between the first movement information associated with wireless headphones  804  and the second movement information associated with electronic watch  806 . In some examples, the first movement information and the second movement information are provided to a time function, such as a dynamic time warping (DTW) function. The DTW function may be applied to the first movement information and second movement information in order to obtain the similarity score. Specifically, various indices from the first movement information may be matched to corresponding indices of the second movement information. The indices may correspond to specific points in time during device movement. For example, a first set of indices associated with movement of wireless headphones  804  may be associated with specific points in time when the user is lifting wireless headphones  804  from a surface. The first set of indices may correspond to a second set of indices associated with movement of electronic watch  806 . The second set of indices may be associated with the same specific points in time as when the user is lifting wireless headphones  804  from a surface, using electronic watch  806 . Based on the application of the DTW function using the matched indices, a similarity score is determined. 
     The similarity score may generally represent the similarity between the concurrent movement of wireless headphones  804  and electronic watch  806  as the user performs the respective movements. For example, as depicted in  FIGS.  8 A- 8 C , the user of electronic watch  806  may grasp wireless headphones  804  and place wireless headphones  804  in an ear of the user. In this case, the similarity score between the first movement information and the second movement information may correspond to a high similarity score (e.g., 95 out of 100). Alternatively, a second user (e.g., a user not associated with electronic watch  806  or otherwise wearing electronic watch  806 ) may grasp wireless headphones  804  and place wireless headphones  804  in the ear of the second user. While the second user is handling wireless headphones  804 , the user wearing electronic watch  806  may be standing still with the electronic watch  806  at their side, or may be performing another movement with electronic watch  806  (e.g., typing on a keyboard). In this case, the similarity score between the first movement information and the second movement information may correspond to a low similarity score (e.g., 2 out of 100). The low similarity score may be based at least in part on the second movement information (e.g., little to no movement) being inconsistent with the first movement information (e.g., movement from a resting position to a user&#39;s ear). 
     In some examples, in accordance with a determination that the similarity score is above a threshold similarity score, a user is identified as an authorized user of one or more electronic devices. In particular, a high similarity score may indicate that the user associated with the movement of wireless headphones  804  and electronic watch  806  is the authorized user of both wireless headphones  804  and mobile device  810  associated with the wireless headphones  804 . This authorization may be based at least in part on an initial authorization of the user via electronic watch  806 . For example, if the similarity score exceeds the threshold similarity score, determination is made whether valid authentication information was previously received from the user at electronic watch  806  (e.g., a passcode, a facial identification, a voice identification, and the like). If such valid authentication information was received, the user is identified as an authorized user of wireless headphones  804  and mobile device  810  associated with wireless headphones  804 . 
     The authorization of the user may be further based on obtaining biometric information from a device, such as the wireless headphones  804 . In particular, as discussed in more detail with respect to  FIG.  9   , biometric information associated with an ear of the user may be obtained from wireless headphones  804 . For example, various signals may be output at wireless headphones  804 , wherein an impulse response is received from wireless headphones  804  based on the output signals. The impulse response may correspond to a biometric representation related to an ear of the user (e.g., an inner-ear representation). In accordance with a determination that the obtained biometric information corresponds to reference biometric information (e.g., a reference inner-ear representation), the user is identified as an authorized user of wireless headphones  804  and associated mobile device  810 . 
     In some examples, the authorization of the user may be based on one or more light profiles or sound profiles associated with the electronic devices. In particular, a first light profile may be detected, such as a light profile corresponding to changes in light during the movement of wireless headphones  804 . One or more light sensors of the wireless headphones  804  may transmit signals to identify a first light profile including changes in detected light while the user moves wireless headphones  804  from a first position to a second position. There may be a light source near the user&#39;s ear, for example, such that the light profile indicates an increase in light as the user places the wireless headphones  804  in the user&#39;s ear. A second light profile may also be detected, such as a light profile corresponding to changes in light during the movement of electronic watch  806 . One or more light sensors of electronic watch  806  may transmit signals to identify a second light profile including changes in detected light while the user moves the electronic watch  806  from a first position to second position. Based on the light source near the user&#39;s ear, the second light profile may also indicate an increase in detected light when the user moves electronic watch  806  towards the user&#39;s ear. Once the light profiles are obtained, determination of a light similarity score is made based on a comparison of the first light profile and the second light profile. The light similarity score may be compared to a light threshold similarity score. In accordance with a determination that the light similarity score is above the light threshold similarity score, the user may be identified as an authorized user of wireless headphones  804  and associated mobile device  810 . 
     Upon identifying the user as an authorized user, an output may be provided to wireless headphones  804 . In general, the output may include audible information personal to the identified user, such as an audible representation of a received message, a personalized playlist, a recorded voice memo, and the like. For example, the user may grasp wireless headphones  804  while wearing electronic watch  806  such that the user is identified as an authorized user as discussed with respect to  FIGS.  8 A- 8 C . Once the user is identified, any messages received at mobile device  810  and/or electronic watch  806  may be identified for playback via wireless headphones  804 . Accordingly, an audible representation of one or more received messages is obtained (e.g., using mobile device  810  and/or electronic watch  806 ) and provided to the user via wireless headphones  804 . 
     In some examples, in accordance with a determination that the similarity score is not above a threshold similarity score, general media is played via wireless headphones  804 . In particular, general user-independent media may be played via wireless headphones  804  instead of media personalized to the user. In some examples, in accordance with a determination that the similarity score is not above a threshold similarity score, a determination is made whether personalized media was playing at wireless headphones  804  as the determination was made. In accordance with a determination that personalized media was playing at wireless headphones  804  as the determination was made, playback of the personalized media stops in order to prevent authorized access to personalized media via wireless headphones  804 . 
     In certain cases, the similarity score may be slightly lower than the threshold similarity score. In such cases, a determination is made whether the similarity score is above a second threshold similarity score, which may be slightly lower than the threshold similarity score (e.g., a threshold score of 80 out of 100 instead of 90 out of 100). In accordance with a determination that the similarity score is above the second threshold similarity score, a prompt may be provided at mobile device  810 . The prompt may include a request for the user to enter an authentication credential at the mobile device  810  (e.g., a passcode, a facial identification, a voice identification, and the like). Based on a user response to the prompt, the user may be identified as an authorized user of wireless headphones  804  and mobile device  810 . Accordingly, an output may then be provided to wireless headphones  804  based on the identification. 
     Referring now to  FIG.  9   , a process for identifying a user as an authorized user based on a biometric representation is illustrated. In general,  FIG.  9    illustrates the placement of a wireless headphone  902  in an ear of a user. Based on a biometric representation obtained by wireless headphone  902 , the user may be authenticated by comparing the biometric representation to a reference biometric representation. For example, after the user places wireless headphone  902  in the ear of the user, a first audio output may be provided at wireless headphone  902 . In particular, the first audio output may include an ultrasonic signal transmitted from one or more microphones of wireless headphone  902 . Based on the audio output, a response may then be obtained by wireless headphone  902 . In some examples, the response is transmitted from wireless headphone  902  to another device, such as a mobile device associated with the user. The received response may include an echo of the ultrasonic signal included in the first audio output. For example, various characteristics of the user&#39;s ear provide an echo of the ultrasonic signal which is unique to the user. Variations in the surface of the user&#39;s ear canal may cause the ultrasonic signal to reflect off the surface and generate an echo having a signature that is associated with the user. For example, a user having a larger ear canal may result in an echo having a longer reverberation time than a user having a smaller ear canal. Furthermore, although only one wireless headphone is depicted in  FIG.  9   , the process described herein may be additionally performed at a corresponding wireless headphone at other ear of the user. 
     In some examples, the first audio output is provided concurrently with a second audio output, wherein the second audio output indicates a communicative coupling of wireless headphone  902  with a mobile device. For instance, when determination is made that the user has placed wireless headphone  902  into an ear of the user, an audible sound (e.g., a chime) is played to the user via the wireless headphone  902  to indicate that wireless headphone has communicatively coupled to another device, such as a mobile device, a tablet, a computer, and the like. In this example, the first audio output may not be audibly distinguishable to the user when provided concurrently with the audible sound indicating communicative coupling with another device. Once the response is received based on the first audio output, an inner-ear representation may be obtained based on the response. In particular, the response may include an impulse response modeled as a discrete time function or a continuous time function, for example. The impulse response may also be stored as a vector representation. 
     In some examples, a similarity score is determined by comparing the inner-ear representation to a stored inner-ear representation. The comparison may include mapping the obtained inner-ear representation into a vector space, and further determining a distance value corresponding to a distance between the mapped inner-ear representation and a stored inner-ear representation. The stored inner-ear representation may be stored at a previous time during a user enrollment process, for example. Based on the distance value obtained as a result of the comparison, the similarity score is determined. As an example, the stored inner-ear representation may be associated with a vector including values indicative of a large ear canal (e.g., 2.7 centimeters in length and 0.9 centimeters in diameter). In this example, the obtained inner-ear representation may be associated with a vector representation including values indicative of a smaller ear canal (e.g., 2.3 centimeters in length and 0.5 centimeters in diameter). In particular, the vector corresponding to the stored inner-ear representation may be located at a position within the vector space corresponding to larger ear canal characteristics, wherein the obtained inner-ear representation may be located at a position within the vector space corresponding to smaller ear canal characteristics. As a result, a large distance value is obtained based on the comparison, which may result in a small similarity score (e.g., 10 out of 100). 
     As another example, the stored inner-ear representation may be associated with a vector representation including values indicative of an average ear canal (e.g., 2.5 centimeters in length and 0.7 centimeters in diameter). In this example, the obtained inner-ear representation may be associated with a vector representation including values indicative of an average ear canal (e.g., 2.6 centimeters in length and 0.7 centimeters in diameter). In particular, both the vector corresponding to the stored inner-ear representation and the vector corresponding to the obtained inner-ear representation may be located in the same area of the vector space corresponding to average ear canal characteristics. Accordingly, a small distance value may be obtained based on the comparison, resulting in a large similarity score (e.g., 90 out of 100). In some examples, the obtained inner-ear representation and stored inner-ear representation are only stored on the mobile device (i.e., not stored on another device such as a server). The obtained inner-ear representation may also be temporarily stored and deleted after comparison to the stored inner-ear representation. 
     Furthermore, in accordance with a determination that the similarity score is above a threshold similarity score, the user may be identified as an authorized user of the first electronic device and the second electronic device. Based on the identification, an output is provided to wireless headphone  902  and a corresponding wireless headphone on another ear of the user (not depicted). For example, an audible representation of a received message, a personalized playlist, or other media personal to the user may be provided as discussed with respect to  FIGS.  8 A- 8 C . In some examples, in accordance with a determination that the similarity score is not above a threshold similarity score, a determination is made whether the similarity score satisfies a similarity criterion. In general, the determined similarity score may be slightly lower than the threshold similarity score. In such cases, a determination is made whether the similarity score satisfies a similarity criterion. The similarity criterion may include determining whether the similarity score is above a second similarity score which may be slightly lower than the threshold similarity score (e.g., a threshold score of 80 out of 100 instead of 90 out of 100). In accordance with a determination that the similarity score satisfies the similarity criterion, determination is made whether the user is an authorized user based on an additional input associated with the user. 
     In general, the additional input associated with the user may include one or more of a speech input and/or gait information associated with the user. For example, once wireless headphone  902  is placed in an ear of the user, a speech input may be received via wireless headphone  902 . In accordance with a determination that the received speech input corresponds to a stored voiceprint, the user may be identified as an authorized user of the wireless headphone  902  and an associated mobile device, for example. In some examples, once wireless headphone  902  is placed in an ear of the user, gait information is detected. In particular, the gait information may be determined at a mobile device associated with wireless headphone  902  and/or an electronic watch associated with wireless headphone  902 . The gait information may include, for example, information regarding a user&#39;s walking and/or running characteristics, such as characteristics related to steps, pace, stride, and the like. The gait information may be further compared to reference gait information. For example, the user&#39;s gait information may have previously been detected and stored (e.g., gait information representing a user&#39;s typical walking and/or running characteristics). In accordance with a determination that the detected gait information corresponds to the reference gait information, the user may be identified as an authorized user of the wireless headphone  902  and an associated mobile device, for example. 
     In some examples, an inner-ear representation is stored during an enrollment or registration step. In particular, an audio output may be provided at the wireless headphone  902  as an initial step to register a user&#39;s ear to wireless headphone  902  (e.g., upon the first use of the headphones). The audio output may also be provided after a reset of wireless headphone  902 . In some examples, the duration of audio output provided to register the ear of the user may be longer than the duration of the audio output provided to obtain a subsequent inner-ear representation (e.g., the registration audio output may be five seconds, and the audio output for identity verification may be two seconds). The audio output for registration may include an ultrasonic signal. A response may then be provided by wireless headphone  902 , such as an impulse response based on the audio output. Based on the impulse response, an inner-ear representation is obtained. Once obtained, the inner-ear representation may be stored as a reference inner-ear representation. 
     In some examples, one or more inputs may be received as a prerequisite to storing an inner-ear representation as the reference inner-ear representation. For example, an input may be received at a mobile device associated with wireless headphone  902 , such as a passcode, a facial identification, a voice identification, and the like. The user may be identified as an authorized user of the mobile device based on the input. In response to the identification, an impulse response representation may be stored and further utilized as the reference inner-ear representation. For example, the mobile device may be transitioned from a locked to an unlocked state based on the identification, such that the inner-ear representation is stored while the mobile device is unlocked. In some examples, the one or more inputs may correspond to a user preference associated with wireless headphone  902 . For example, the user may interact with an associated mobile device to activate one or more features, such as a feature including an option to audibly announce received messages (e.g., text and/or e-mail messages received at the mobile device) via the wireless headphone  902 . In response to activation of the feature to audible announce received messages, an impulse response representation may be stored and further utilized as the reference inner-ear representation. In some examples, one or more prompts are proactively provided on the mobile device regarding the registration of the ear of the user with wireless headphone  902 . In particular, the mobile device may display a prompt that recites “Please wait five seconds while your headphones are registered.” The prompt may be concurrently displayed with a registration status indicator, for example. In some examples, the audio output is provided at wireless headphone  902  during the duration while the prompt is being displayed on the mobile device. As a result, an impulse response representation, based on the audio output, may be stored and further utilized as the reference inner-ear representation. 
       FIG.  10    illustrates process  1000  for user identification using headphones according to various examples. Process  1000  is performed, for example, using one or more electronic devices implementing a digital assistant. In some examples, process  1000  is performed using a client-server system (e.g., system  100 ), and the blocks of process  1000  are divided up in any manner between the server (e.g., DA server  106 ) and a client device. In other examples, the blocks of process  1000  are divided up between the server and multiple client devices (e.g., a mobile device and a smart watch). Thus, while portions of process  1000  are described herein as being performed by particular devices of a client-server system, it will be appreciated that process  1000  is not so limited. In other examples, process  1000  is performed using only a client device (e.g., user device  104 ) or only multiple client devices. In process  1000 , some blocks are, optionally, combined, the order of some blocks is, optionally, changed, and some blocks are, optionally, omitted. In some examples, additional steps may be performed in combination with the process  1000 . 
     With reference to  FIG.  10   , at block  1002 , first movement information, corresponding to movement of a second electronic device, is detected. In some examples, the user is identified as an authorized user based on the determination that the similarity score is above the threshold similarity score. In some examples, the second electronic device includes at least one in-ear headphone and at least one microphone. In some examples, detecting first movement information corresponding to movement of the second electronic device includes determining whether the first movement information corresponds to a first movement profile, wherein the first movement profile includes a known movement pattern of a first device type. In some examples, the first movement profile includes a first position corresponding to a resting position, a second position corresponding to an in-ear position, and a movement pattern from the first position to the second position, wherein the movement pattern includes expected acceleration from a plurality of axes associated with the second electronic device. In some examples, detecting first movement information corresponding to movement of the second electronic device includes receiving, from the second electronic device, a plurality of signals associated with at least one accelerometer of the second electronic device, and determining a root square sum of the plurality of signals, and obtaining the first movement information based on the root square sum. By determining whether movement information corresponds to known movement patterns, the system improves accuracy by focusing on movement that is consistent with placing headphones in an ear of the user. Improving accuracy enhances the operability of the device and makes the device more efficient which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. 
     At block  1004 , second movement information, corresponding to movement of a third electronic device, is detected. In some examples, the third electronic device corresponds to an electronic watch. In some examples, detecting second movement information corresponding to movement of the third electronic device includes determining whether the second movement information corresponds to a second movement profile, wherein the second movement profile corresponds to a known movement pattern of a second device type. In some examples, the second movement profile includes a first motion corresponding to obtaining an item from a first position, a second motion corresponding to releasing an item to a second position, and a movement pattern from the first position to the second position, wherein the movement pattern includes expected acceleration from a plurality of axes associated with the third electronic device. In some examples, detecting second movement information corresponding to movement of the third electronic device includes receiving, from the third electronic device, a plurality of signals associated with an accelerometer of the third electronic device, and determining a root square sum of the plurality of signals, and obtaining the second movement information based on the root square sum. By determining whether movement information corresponding to known movement patterns, the system improves accuracy by focusing on movement that is consistent with placing headphones in an ear of the user. Improving accuracy enhances the operability of the device and makes the device more efficient which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. 
     At block  1006 , a similarity score is determined based on the first movement information and the second movement information. At block  1008 , a determination is made whether the similarity score is above a threshold similarity score. In some examples, determining the similarity score based on the first movement information and the second movement information includes providing the first movement information and the second movement information to a time function, and receiving, as an output from the time function, the similarity score. By utilizing a time function on a mobile device to determine the similarity between the detected movement information of headphones and an electronic watch, the system improves accuracy by leveraging the processing power of the mobile device. Improving accuracy enhances the operability of the device and makes the device more efficient which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. 
     At block  1010 , in accordance with a determination that the similarity score is above a threshold similarity score, a user is identified as an authorized user of the first electronic device and the second electronic device. In some examples, identifying the user as an authorized user of the first electronic device and the second electronic device includes, in accordance with a determination that valid authentication information was received from the user at the third electronic device, identifying the user as an authorized user of the first electronic device and the second electronic device. In some examples, identifying the user as an authorized user of the first electronic device and the second electronic device includes obtaining, from the second electronic device, biometric information, and in accordance with a determination that the obtained biometric information corresponds to reference biometric information, identifying the user as an authorized user of the first electronic device and the second electronic device. In some examples, identifying the user as an authorized user of the first electronic device and the second electronic device includes detecting a first light profile, wherein the first light profile corresponds to changes in light during the movement of the second electronic device, detecting a second light profile, wherein the second light profile corresponds to changes in light during the movement of the third electronic device, determining a second similarity score based on a comparison of the first light profile and the second light profile, and in accordance with a determination that the second similarity score is above a second threshold similarity score, identifying the user as an authorized user of the first electronic device and the second electronic device. In some examples, identifying the user as an authorized user of the first electronic device and the second electronic device includes detecting a first sound profile, wherein the first sound profile corresponds to changes in audio amplitude during the movement of the second electronic device, detecting a second sound profile, wherein the second sound profile corresponds to changes in audio amplitude during the movement of the third electronic device, determining a third similarity score based on a comparison of the first sound profile and the second sound profile, and in accordance with a determination that the third similarity score is above a third threshold similarity score, identifying the user as an authorized user of the first electronic device and the second electronic device. By utilizing additional factors such as light and sound, the system improves accuracy by providing additional layers of authentication when necessary. Improving accuracy enhances the operability of the device and makes the device more efficient which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. 
     At block  1012 , an output is provided to the second electronic device based on the identification of the user. In some examples, providing, based on the identification, an output to the second electronic device includes providing, to the second electronic device, an audible representation of a received message. In some examples, in accordance with a determination that the similarity score is not above a threshold similarity score, a determination is made whether personalized media is playing at the second electronic device, and in accordance with a determination that personalized media is playing at the second electronic device, playback of the personalized media the second electronic device is ceased. In some examples, in accordance with a determination that the similarity score is not above a threshold similarity score, determination is made at block  1016  whether the similarity score is above a second threshold similarity score, wherein the second threshold similarity score is lower than the threshold similarity score. In some examples, in accordance with a determination that the similarity score is above the second threshold similarity score, a prompt is provided at the first electronic device, an input responsive to the prompt is received, and identification is made, based on the input, of the user as an authorized user of the first electronic device and the second electronic device. In some examples, based on the identification, an output is provided to the second electronic device. By selectively providing outputs based on headphone authentication, the system improves user experience by providing relevant content when appropriate. Improving user experience enhances the operability of the device and enables the user to use the device more quickly and efficiently. 
     The operations described above with reference to  FIG.  10    are optionally implemented by components depicted in  FIGS.  1 - 4 ,  6 A -B, and  7 A-C. For example, the operations of process  800  may be implemented by one or more of operating system  718 , applications module  724 , I/O processing module  728 , STT processing module  730 , natural language processing module  732 , vocabulary index  744 , task flow processing module  736 , service processing module  738 , media service(s)  120 - 1 , or processor(s)  220 ,  410 , and  704 . It would be clear to a person having ordinary skill in the art how other processes are implemented based on the components depicted in  FIGS.  1 - 4 ,  6 A -B, and  7 A-C. 
       FIG.  11    illustrates process  1100  for user identification using headphones according to various examples. Process  1100  is performed, for example, using one or more electronic devices implementing a digital assistant. In some examples, process  1100  is performed using a client-server system (e.g., system  100 ), and the blocks of process  1100  are divided up in any manner between the server (e.g., DA server  106 ) and a client device. In other examples, the blocks of process  1100  are divided up between the server and multiple client devices (e.g., a mobile device and a smart watch). Thus, while portions of process  1100  are described herein as being performed by particular devices of a client-server system, it will be appreciated that process  1100  is not so limited. In other examples, process  1100  is performed using only a client device (e.g., user device  104 ) or only multiple client devices. In process  1100 , some blocks are, optionally, combined, the order of some blocks is, optionally, changed, and some blocks are, optionally, omitted. In some examples, additional steps may be performed in combination with the process  1100 . 
     With reference to  FIG.  11   , at block  1102 , a first audio output is caused to be provided at a second electronic device. In some examples, the first audio output includes an ultrasonic signal transmitted from the second electronic device. In some examples, the received response comprises an echo of an ultrasonic signal included in the first audio output. In some examples, the echo comprises an impulse response based on characteristics associated with an ear of the user. In some examples, the first audio output is provided concurrently with a second audio output, wherein the second audio output indicates a communicative coupling of the first electronic device with the second electronic device. By concurrently providing the first audio output with an output associated with communicative coupling, the system improves user experience by reducing or eliminating the noticeability of the first audio signal to the user. Improving user experience enhances the operability of the device and enables the user to use the device more quickly and efficiently. 
     At block  1104 , a response is received from the second electronic device based on the provided first audio output. At block  1106 , an inner-ear representation is obtained based on the response. In some examples, obtaining an inner-ear representation based on the response includes obtaining an impulse response from the received response, wherein the received response includes an echo of the audio output, and storing the impulse response as a vector. At block  1108 , a similarity score is determined by comparing the inner-ear representation to a stored inner-ear representation. In some examples, determining a similarity score by comparing the inner-ear representation to a stored inner-ear representation includes mapping the obtained inner-ear representation into a vector space, determining a distance value corresponding to a distance between the mapped inner-ear representation and a stored inner-ear representation, and obtaining the similarity score based on the distance value. By utilizing a vector space to determine the similarity of the representations, the system improves accuracy by leveraging distance metric learning. Improving accuracy enhances the operability of the device and makes the device more efficient which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. 
     At block  1110 , a determination is made whether the similarity score is above a threshold similarity score. At block  1112 , in accordance with a determination that the similarity score is above a threshold similarity score, a user is identified as an authorized user of the first electronic device and the second electronic device. In some examples, in accordance with a determination that the similarity score is not above a threshold similarity score, a determination is made whether the similarity score satisfies a similarity criterion, wherein in accordance with a determination that the similarity score satisfies the similarity criterion, determination is made whether the user is an authorized user based on an input associated with the user. In some examples, determining whether the similarity score satisfies a similarity criterion includes determining whether the similarity score is above a second threshold similarity score, wherein the second threshold similarity score is lower than the threshold similarity score. In some examples, determining whether the user is an authorized user based on an input associated with the user includes receiving the input associated with the user, wherein the input includes a speech input, and in accordance with a determination that the speech input corresponds to a stored voiceprint, identifying, based on the received input, the user as an authorized user of the first electronic device and the second electronic device. In some examples, determining whether the user is an authorized user based on an input associated with the user includes receiving the input associated with the user, wherein the input includes detected gait information, and in accordance with a determination that the detected gait information corresponds to reference gait information, identifying, based on the received input, the user as an authorized user of the first electronic device and the second electronic device. By utilizing additional factors such as biometrics, gait, and voice, the system improves accuracy by providing additional layers of authentication when necessary. Improving accuracy enhances the operability of the device and makes the device more efficient which, additionally, reduces power usage and improves battery life of the device by enabling the user to use the device more quickly and efficiently. 
     At block  1114 , an output is provided, based on the identification, to the second electronic device. In some examples, providing, based on the identification, an output to the second electronic device includes providing, to the second electronic device, an audible representation of a received message. In some examples, a second audio output is caused to be provided at the second electronic device, a second response is received from the second electronic device based on the provided second audio output, and based on the received second response, an impulse response representation is stored as the stored inner-ear representation. In some examples, the first audio output is associated with a first duration and the second audio output is associated with a second duration longer than the first duration. In some examples, an input associated with the user is received, based on the received input, the user is identified as an authorized user of the first electronic device, and in response to identifying, based on the received input, the user as an authorized user of the first electronic device, an impulse response representation is stored as the stored inner-ear representation. In some examples, in response to identifying, based on the received input, the user as an authorized user of the first electronic device, the first electronic device is unlocked, and while the first electronic device is unlocked, the impulse response representation is stored as the stored inner-ear representation. In some examples, the user is identified as an authorized user of the first electronic device, an input is received from the user corresponding to a user preference associated with the second electronic device, and in response to receiving the input, an impulse response representation is stored as the stored inner-ear representation. In some examples, a prompt associated with registration of the second electronic device is provided, an input responsive to the prompt is received from the user, and in response to receiving the input, an impulse response representation is stored as the stored inner-ear representation. By utilizing additional conditions such as prior user authentication, the system improves device security only storing a reference ear representation when appropriate. Improving device security enhances the operability of the device and improves user experience, enabling the user to use the device more quickly and efficiently. 
     The operations described above with reference to  FIG.  11    are optionally implemented by components depicted in  FIGS.  1 - 4 ,  6 A -B, and  7 A-C. For example, the operations of process  800  may be implemented by one or more of operating system  718 , applications module  724 , I/O processing module  728 , STT processing module  730 , natural language processing module  732 , vocabulary index  744 , task flow processing module  736 , service processing module  738 , media service(s)  120 - 1 , or processor(s)  220 ,  410 , and  704 . It would be clear to a person having ordinary skill in the art how other processes are implemented based on the components depicted in  FIGS.  1 - 4 ,  6 A -B, and  7 A-C. 
     In accordance with some implementations, a computer-readable storage medium (e.g., a non-transitory computer readable storage medium) is provided, the computer-readable storage medium storing one or more programs for execution by one or more processors of an electronic device, the one or more programs including instructions for performing any of the methods or processes described herein. 
     In accordance with some implementations, an electronic device a portable electronic device) is provided that comprises means for performing any of the methods or processes described herein. 
     In accordance with some implementations, an electronic device (e.g., a portable electronic device) is provided that comprises a processing unit configured to perform any of the methods or processes described herein. 
     In accordance with some implementations, an electronic device (e.g., a portable electronic device) is provided that comprises one or more processors and memory storing one or more programs for execution by the one or more processors, the one or more programs including instructions for performing any of the methods or processes described herein. 
     The foregoing description, for purpose of explanation, has been described with reference to specific embodiments. However, the illustrative discussions above are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in view of the above teachings. The embodiments were chosen and described in order to best explain the principles of the techniques and their practical applications. Others skilled in the art are thereby enabled to best utilize the techniques and various embodiments with various modifications as are suited to the particular use contemplated. 
     Although the disclosure and examples have been fully described with reference to the accompanying drawings, it is to be noted that various changes and modifications will become apparent to those skilled in the art. Such changes and modifications are to be understood as being included within the scope of the disclosure and examples as defined by the claims. 
     As described above, one aspect of the present technology is the gathering and use of data available from various sources to improve user identification using headphones. The present disclosure contemplates that in some instances, this gathered data may include personal information data that uniquely identifies or can be used to contact or locate a specific person. Such personal information data can include demographic data, location-based data, telephone numbers, email addresses, twitter IDs, home addresses, data or records relating to a user&#39;s health or level of fitness (e.g., vital signs measurements, medication information, exercise information), date of birth, or any other identifying or personal information. 
     The present disclosure recognizes that the use of such personal information data, in the present technology, can be used to the benefit of users. For example, the personal information data can be used to identify the typical arm raise profile of a user when the user places headphones in the user&#39;s ear. Other uses for personal information data that benefit the user are also contemplated by the present disclosure. For instance, information related to gait, voiceprints, or ear representations may be stored and used to authenticate a user. 
     The present disclosure contemplates that the entities responsible for the collection, analysis, disclosure, transfer, storage, or other use of such personal information data will comply with well-established privacy policies and/or privacy practices. In particular, such entities should implement and consistently use privacy policies and practices that are generally recognized as meeting or exceeding industry or governmental requirements for maintaining personal information data private and secure. Such policies should be easily accessible by users, and should be updated as the collection and/or use of data changes. Personal information from users should be collected for legitimate and reasonable uses of the entity and not shared or sold outside of those legitimate uses. Further, such collection/sharing should occur after receiving the informed consent of the users. Additionally, such entities should consider taking any needed steps for safeguarding and securing access to such personal information data and ensuring that others with access to the personal information data adhere to their privacy policies and procedures. Further, such entities can subject themselves to evaluation by third parties to certify their adherence to widely accepted privacy policies and practices. In addition, policies and practices should be adapted for the particular types of personal information data being collected and/or accessed and adapted to applicable laws and standards, including jurisdiction-specific considerations. For instance, in the US, collection of or access to certain health data may be governed by federal and/or state laws, such as the Health Insurance Portability and Accountability Act (HIPAA); whereas health data in other countries may be subject to other regulations and policies and should be handled accordingly. Hence different privacy practices should be maintained for different personal data types in each country. 
     Despite the foregoing, the present disclosure also contemplates embodiments in which users selectively block the use of, or access to, personal information data. That is, the present disclosure contemplates that hardware and/or software elements can be provided to prevent or block access to such personal information data. For example, in the case of providing relevant data items to a user, the present technology can be configured to allow users to select to “opt in” or “opt out” of participation in the collection of personal information data during registration for services or anytime thereafter. In another examples, users can select to not provide personal information for user identification using headphones, such as information associated with typical user motions or ear representations. In addition to providing “opt in” and “opt out” options, the present disclosure contemplates providing notifications relating to the access or use of personal information. For instance, a user may be notified prior to the device performing user identification using headphones, informing the user that their personal information data will be accessed, and providing additional opportunities to “opt in” or “opt out.” 
     Moreover, it is the intent of the present disclosure that personal information data should be managed and handled in a way to minimize risks of unintentional or unauthorized access or use. Risk can be minimized by limiting the collection of data and deleting data once it is no longer needed. In addition, and when applicable, including in certain health related applications, data de-identification can be used to protect a user&#39;s privacy. De-identification may be facilitated, when appropriate, by removing specific identifiers (e.g., date of birth, etc.), controlling the amount or specificity of data stored (e.g., collecting location data at a city level rather than at an address level), controlling how data is stored (e.g., aggregating data across users), and/or other methods. 
     Therefore, although the present disclosure broadly covers use of personal information data to implement one or more various disclosed embodiments, the present disclosure also contemplates that the various embodiments can also be implemented without the need for accessing such personal information data. That is, the various embodiments of the present technology are not rendered inoperable due to the lack of all or a portion of such personal information data. For example, data items may be selected and provided to users by inferring preferences based on non-personal information data or a bare minimum amount of personal information, such as the content being requested by the device associated with a user, other non-personal information available for user identification using headphones, or publicly available information.

Metadata:
Filing Date: 20220705
Publication Date: 20230704
Grant Date: 20230704
Priority Date: 20200721
Inventors: GONG, Jun
LAPUT, Gierad
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F3/011", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F21/32", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R2420/07", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R1/08", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/16", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/165", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/1016", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F21/84", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/017", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F18/22", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F9/542", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/1041", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R2460/07", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R1/1041", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R1/1016", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W12/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W12/68", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F21/32", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/017", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06V20/52", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06V40/20", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06V10/82", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/1091", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R2460/07", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F21/32", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F21/84", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R2420/07", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/011", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/017", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F9/542", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/16", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/165", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/08", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/1041", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R2460/07", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F18/22", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 79689557