Patent Publication Number: US-2023138565-A1

Title: Testing computer program accessibility for users with disabilities, such as for use with mobile phones

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. Pat. Application No. 17/519,466, filed on Nov. 4, 2021, entitled ENSURING THAT COMPUTER PROGRAMS ARE ACCESSIBLE TO USERS WITH DISABILITIES, SUCH AS FOR USE WITH MOBILE PHONES, which is hereby incorporated by reference in its entirety. 
    
    
     BACKGROUND 
     The internet strives to operate as an inclusive place. However, those with disabilities may still have difficulty finding websites and information online because most user interfaces are targeted toward users who can see, hear, and use a keyboard and mouse. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Detailed descriptions of implementations of the present invention will be described and explained through the use of the accompanying drawings. 
         FIG.  1    shows a user interface to generate an indication of an appropriate test to perform to ensure that a user interface provides intended information to a large set of users, including users with disabilities. 
         FIG.  2    shows user interface categories associated with a web page. 
         FIG.  3    shows user interface categories associated with a native application. 
         FIGS.  4 A- 4 B  show selection of an appropriate test. 
         FIG.  5    is a flowchart that illustrates a process to generate an indication of an appropriate test to perform to ensure that a user interface provides intended information to a user. 
         FIG.  6    is a block diagram that illustrates an example of a computer system in which at least some operations described herein can be implemented. 
     
    
    
     The technologies described herein will become more apparent to those skilled in the art from studying the Detailed Description in conjunction with the drawings. Embodiments or implementations describing aspects of the invention are illustrated by way of example, and the same references can indicate similar elements. While the drawings depict various implementations for the purpose of illustration, those skilled in the art will recognize that alternative implementations can be employed without departing from the principles of the present technologies. Accordingly, while specific implementations are shown in the drawings, the technology is amenable to various modifications. 
     DETAILED DESCRIPTION 
     Disclosed here is a system and method to allow users with a disability to interact with computer programs. To ensure that the computer programs are accessible to users with a disability, prior to releasing the computer program, the system generates an indication of an appropriate test to perform to ensure that a user interface can provide intended information even to a user with a disability. The system can obtain a representation of the user interface to present to a user. The representation can be a design document describing the user interface, a sketch of the user interface, or a functioning user interface. The user interface can be a graphical user interface, an audio interface, or a haptic user interface. The system can identify an element associated with the user interface, such as a menu, a button, a link, etc., where the element is configured to provide information to the user, however, the user interface presentation of the element at least partially fails to provide the information to the user, due to the user’s particular disability or severity of that disability. 
     Based on the element, the system can determine an appropriate test to perform, where the appropriate test indicates a test to perform with a keyboard, a gesture test to perform with a mobile screen reader (e.g. TalkBack or VoiceOver), and/or an audio test to perform with a screen reader. The system can generate the indication of the appropriate test. For example, when the appropriate test includes the test to perform with the keyboard, the system can indicate a keyboard key and an effect caused by activating the keyboard key. When the appropriate test includes the gesture test, the system can indicate a gesture and an effect caused by performing the gesture. When the appropriate test includes the audio test, the system can indicate audio and a function to be performed by the audio. The system can provide the presentation prior to releasing the user interface to the user, to ensure that the appropriate tests are performed. 
     A screen reader is a form of assistive technology (AT) that renders text and image content as speech or haptic output, e.g. braille output. A refreshable braille display or braille terminal is an electro-mechanical device for displaying characters, usually by means of round-tipped pins raised through holes in a flat surface. Visually impaired computer users who cannot use a standard computer monitor can use it to read text output. Deafblind computer users may also use refreshable braille displays. Speech synthesizers are also commonly used for the same task, and a blind user may switch between the two systems or use both at the same time depending on circumstances. 
     Screen readers are essential to people who are blind, and are useful to people who are visually impaired, illiterate, or have a learning disability. Screen readers are software applications that attempt to convey what people with normal eyesight see on a display to their users via non-visual means, like text-to-speech, sound icons, or a Braille device. They do this by applying a wide variety of techniques that include, for example, interacting with dedicated accessibility APIs, using various operating system features (like inter-process communication and querying user interface properties), and employing hooking techniques. 
     In computer programming, the term hooking covers a range of techniques used to alter or augment the behavior of an operating system, of applications, or of other software components by intercepting function calls or messages or events passed between software components. Code that handles such intercepted function calls, events or messages is called a hook. Examples of hooking can include intercepting an output from an application sent to the display, to add audio or Braille indications of the output. 
     The description and associated drawings are illustrative examples and are not to be construed as limiting. This disclosure provides certain details for a thorough understanding and enabling description of these examples. One skilled in the relevant technology will understand, however, that the invention can be practiced without many of these details. Likewise, one skilled in the relevant technology will understand that the invention can include well-known structures or features that are not shown or described in detail, to avoid unnecessarily obscuring the descriptions of examples. 
     Ensuring That Computer Programs are Accessible to Users With a Disability 
       FIG.  1    shows a user interface to generate an indication of an appropriate test to perform to ensure that a user interface provides intended information to a large set of users, including users with disabilities. The user interface  100  enables a user to indicate the type of tests to perform on a program, to ensure that a program  110  is accessible to users with a disability. The users with a disability may not be able to use the mouse or the keyboard, or they may not be able to read due to blindness, limited literacy, or other reasons. 
     The program  110  can include web programs, such as web pages  110 A or native applications  110 B. The native applications  110 B can be associated with various devices such as mobile phones, computers, tablets, wearable devices, etc. User interfaces of programs  110 A,  110 B can include graphical user interfaces, audio user interfaces, and/or haptic user interfaces. 
       FIG.  2    shows user interface categories associated with the web page. A hardware or software processor executing instructions described in this application can determine the type of program associated with the user interface, and based on the type of program can determine the multiple categories associated with user interface elements. When the program is a web page  110 A in  FIG.  1   , the processor creates the following categories: HTML  200 , header (or banner)  210 , navigation  220 , main  230 , form  240 , and footer (contentinfo)  250 . Other categories can be included such as aside, article, section. The aside HTML element represents a portion of a document whose content is only indirectly related to the document’s main content. Asides are frequently presented as sidebars or call-out boxes. The article HTML element represents a self-contained composition in a document, page, application, or site, which is intended to be independently distributable or reusable (e.g., in syndication). Examples include: a forum post, a magazine or newspaper article, or a blog entry, a product card, a user-submitted comment, an interactive widget or gadget, or any other independent item of content. The section element is a structural HTML element used to group together related elements. Each section typically includes one or more heading elements and additional elements presenting related content. 
     The HTML  200  element indicates that the document is an HTML document. HyperText Markup Language, or HTML, is the standard markup language for documents designed to be displayed in a web browser. The HTML  200  element can include user interface elements such as basic web page  201 , skip link  202 , header / banner  203 , navigation menu  204 , main landmark  205 , and/or footer / content info  206 . 
     The header  210  is a content sectioning element allowing organization of the document content into logical pieces. Header  210  represents introductory content, typically a group of introductory or navigational aids. Header  210  may contain some heading elements but also a logo, a search form, an author name, and other elements. The header  210  element can include user interface elements such as search input, header/banner, and/or navigation menu (not pictured). 
     The navigation  220  element represents a section of a page that serves the purpose of providing navigation links, either within the current document or to other documents. Common examples of navigation sections are menus, tables of contents, and indexes. The navigation  220  element can include user interface elements such as search input  221 , pagination nav  222 , button  223 , link  224 , and/or navigation menu  225 . 
     The main  230  element represents the dominant content of the &lt;body&gt; of a document. The main content area consists of content that is directly related to or expands upon the central topic of a document, or the central functionality of an application. The main  230  element can include user interface elements such as: Alert; Animation; Expander accordion; Figure: map, chart, table; Heading: h1, h2, h3; Image: jpg, gif, png, svg; Modal Dialog; Separator / horizontal rule; Sticky element; Table; Toast Snackbar; Tooltip; Video/audio player; Pagination nav; Progress bar; Link; Carousel; and/or Main landmark (not pictured). 
     The form  240  element represents a document section containing interactive controls for submitting information. The form  240  element can include user interface elements such as: Alert; Checkbox; Date picker dialog; Dropdown listbox select; Hint, help, or error; Listbox with inline autocomplete; Number input; Password input; Radio button; Range slider input; Separator / horizontal rule; Star rating; Stepper input; Text input; Toast Snackbar; Toggle switch; Progress bar; and/or Button (not pictured). 
     The footer  250  element is a content sectioning element. The footer  250  element represents a footer for its nearest sectioning content or sectioning root element. A &lt;footer&gt; typically contains information about the author of the section, copyright data, or links to related documents. The footer  250  element can include user interface elements such as navigation menu and/or footer / content info (not pictured). 
       FIG.  3    shows user interface categories associated with a native application. A processor based on the type of program can determine the multiple categories associated with user interface elements. When the program is a native application  110 B in  FIG.  1   , the processor creates the following categories: controls  300  and notifications  310 . The processor chooses the categories so that user interface elements belonging to native applications running on various platforms such as Android and iOS can be categorized in the categories  300 ,  300 . The processor can also create category specific to a particular platform such as iOS. Those categories can include bars and views. 
     Controls  300  are user interface elements that display content or enable interaction. Controls are the building blocks of the user interface. Controls  300  can include the following user elements: Button; Captcha; Carousel; Checkbox; Link; Menu; Pagination control; Picker / Spinner / Dropdown; Radio button; Range slider; Segmented Control / Tab; Stepper; Table row button; Text input; and/or Toggle switch. 
     The notifications  310  include Alert/Modal Dialog and/or Toast/snack bar/banner notification. Alert/Modal Dialog notifications interrupt users and demand an action. They are appropriate when a user’s attention needs to be directed toward important information. Toast, snackbar, banner all refer to a graphical control element that communicates certain events to the user without forcing the user to react to this notification immediately, unlike conventional pop-up windows. Desktop notifications usually disappear automatically after a short amount of time. Often their content is then stored in some widget that allows the users to access past notifications at a more convenient time. 
     A bar can include a navigation bar, search bar, sidebar, status bar, tab bar, toolbar, etc. The bar can provide various information to the user or receive input from the user. The bar can be vertical, or horizontal on the screen. 
     A view represents a single item on the user interface. It could be a control such as a button or slider, an input text field, or perhaps an image. A view covers a specific area on the screen and can be configured to respond to touch events. 
       FIGS.  4 A- 4 B  show selection of an appropriate test. When the appropriate user interface element  400  shown in  FIGS.  4 A- 4 B ,  410  shown in  FIG.  4 B  (only 2 labeled for brevity) is selected, the processor can generate the presentation  460  including the indication  420  of the appropriate test. The processor can select the user interface elements  400 ,  410  by analyzing the user interface and determining the user interface elements  400 ,  410  included in the user interface. Alternatively, the user can manually select the user interface elements  400 ,  410 . 
     The indication  420  of the appropriate test can be split into 3 categories: keyboard test  430 A, gesture test  440 A, and audio test  450 A. 
     When the appropriate test includes the keyboard test  430 A, the test indicates a keyboard key and an effect caused by activating the keyboard key. For example, for testing the user interface element checkbox, the test indicates:
     1. Test with the keyboard   Tab or arrow keys: Focus visibly moves to the checkbox   Spacebar: Activates on iOS and Android   Enter: Activates on Android.   

     The tests  430 A,  440 A,  450 A can indicate keys to test specific operating systems and expected effects that depend on the operating system. 
     When the appropriate test includes the gesture test  440 A, the test indicates a gesture and an effect caused by performing the gesture. For example, for testing the user interface element checkbox, the test indicates:
     Swipe: Focus moves to the element, expresses its name, role, state   Doubletap: Checkbox toggles between checked and unchecked states.   

     When the appropriate test includes the audio test  450 A, the test indicates audio and a function to be performed by the audio. For example, for testing the user interface element checkbox, the test indicates that the audio should include:
     Name: Describes the purpose of the control and matches the visible label   Role: Identifies itself as a checkbox in Android and a Button in iOS   Group: Visible label is grouped with the checkbox in a single swipe   State: Expresses its state (disabled/dimmed, checked, not checked).   

     For both native applications and web programs, the group indicates to check that labels and controls are a single object to the user. For example, if the user element is a checkbox, tapping on the checkbox label should activate the checkbox rather than being forced to tap on the tiny checkbox. 
     The presentation  460  can be made human readable format or can be in a machine readable format because the testing can be performed automatically or manually. The indication  420  of the appropriate test can be editable to allow modification to the indicated tests  430 A,  440 A,  450 A. 
       FIG.  4 B  shows selection of multiple appropriate tests. In  FIG.  4 B , both the checkbox  400  and the menu  410  have been selected. The processor appends the indication  420 ,  470  of the appropriate tests to create the presentation  460 . 
     For testing the user interface element “menu,” the keyboard test  430 B indicates:
     1. Test with the keyboard   Tab or arrow keys: Focus visibly moves, confined within the menu   Escape: The menu closes and returns focus to the button that launched it   Space: Any buttons or links are activated on iOS and Android   Enter: Any buttons or links are activated on Android.   

     When the appropriate test includes the gesture test  440 B, the test indicates a gesture and an effect caused by performing the gesture. For testing the user interface element “menu,” the gesture test  440 B indicates:
     Swipe: Focus moves, confined within the menu.   Doubletap: This typically activates most elements.   

     The gesture test  440 B tests traversing and interacting with the screen for people who are blind and cannot see the screen. The gesture test can test that swiping across the screen moves the screenreader “focus” to different elements one by one. 
     When the appropriate test includes the audio test  450 B, the test indicates audio and a function to be performed by the audio. For example, for testing the user interface element “menu,” the audio test  450 B indicates that the audio should include:
     Name: Purpose of menu is clear.   Role: May identify itself as a menu, sidebar, or panel. Confining the user within the menu communicates the context to the screen reader user that there is a menu or modal present.   State: When open, other content is inert. Expands/collapses, closes/opens states are typically announced for a menu, sidebar, or panel.   

     The tests  430 ,  440 ,  450  can be written in a human readable format, and/or in a machine-readable format. The tests  430 ,  440 ,  450  can be performed manually or automatically. To perform an automated test, the processor can receive the indication of the appropriate tests  430 ,  440 ,  450  in either human readable format or in a machine readable format. Based on the indication of the appropriate tests  430 ,  440 ,  450 , the processor can determine which tests to perform. 
     For example, if the test indicates an audio test  450 A,  450 B, the processor can execute the program under test, and the audio test for the particular element under test. In addition, the processor can play the audio associated with the particular element and perform natural language processing on the audio to determine the content of the audio and whether the content of the audio matches the particular element under test. 
     For example, if the element is a checkbox, the processor can determine whether the audio corresponds to the output specified in the “Name,” “Role,” “Group,” and “State” requirements of the audio test  450 A. In particular, to pass the “Name” component of the audio test  450 A, the processor can determine whether the audio contains the specified output, namely whether the audio correctly states the name of the checkbox. To pass the “Role” component of the audio test  450 A, the processor can determine whether the audio contains the specified output, namely whether the audio correctly states that the element under test is a checkbox in Android, or a button in iOS. To pass the “Group” component of the audio test  450 A, the processor can determine whether the audio contains the specified output, namely whether the audio correctly states that the name of the element under test is grouped with the checkbox. To pass the “Group” component of the audio test  450 A, the processor can also determine that tapping on the checkbox label activates the checkbox rather than being forced to tap on the tiny checkbox. Label and checkbox should act as a single unit. Finally, to pass the “State” component of the audio test  450 A, the processor can determine whether the audio contains the specified output, namely whether the audio correctly states if the element under test is checked or unchecked. If the audio passes all four of the tests, the processor can determine that the program satisfies the audio test  450 A. If the audio does not pass all four of the tests, the processor can indicate that the program has failed the audio test. 
       FIG.  5    is a flowchart that illustrates a process to generate an indication of an appropriate test to perform to ensure that a user interface provides intended information to a user. In step  500 , a hardware or software processor executing instructions described in this application can obtain a representation of the user interface to present to a user. The representation of the user interface can be a design describing the user interface, and/or a functioning user interface. The user interface can include a user interface, an audio user interface, and/or a haptic user interface. 
     In step  510 , the processor can determine an element associated with the user interface such as a radio button, text input, capture, etc. The element is configured to provide information to the user, however, the user interface presentation of the element at least partially fails to provide the information to the user. For example, the user can be disabled and not be able to see and may need to interact with the user interface using audio or gestures when appropriate. The user may not be able to use the mouse and may need to interact with the user interface using a keyboard. 
     In step  520 , based on the element, the processor can determine an appropriate test to perform. To accommodate various disabilities, the appropriate test can indicate a test to perform with a keyboard, a gesture test to perform with a mobile screen reader, and an audio test to perform with a screen reader. 
     In step  530 , the processor can generate the indication of the appropriate test categorized by the type of test. When the appropriate test includes the test to perform with the keyboard, the appropriate test indication can include a keyboard key and an effect caused by activating the keyboard key. When the appropriate test includes the gesture test, the appropriate test indication can include a gesture and an effect caused by performing the gesture. When the appropriate test includes the audio test, the appropriate test indication can include audio and a function to be performed by the audio. The processor can provide the presentation prior to releasing the user interface to the user. 
     In step  540 , the processor can provide the indication of the appropriate test prior to releasing the user interface to the user. The indication can be a presentation such as a multimedia presentation, text presentation, an audio presentation, a multimedia presentation, etc. The indication can be editable. Prior to releasing the user interface to the user, the processor can perform the appropriate test is performed on the user interface and can indicate when the user interface passed the appropriate test. 
     The processor can determine a type of program associated with the user interface. Based on the type of program, the processor can determine multiple categories associated with the user interface. The processor can determine a type of element by categorizing the element associated with the user interface into a category among the multiple categories. Finally, the processor can enable a selection of the appropriate test by presenting the multiple categories, the element, and the category associated with the element. 
     The user interface can be a web page. When the user interface is a web page, the processor can determine multiple categories associated with the user interface including at least four of: HTML, header, navigation, main, form, and footer. The processor can categorize the element associated with the user interface into a category among the multiple categories. The processor can enable a selection of the appropriate test by presenting the multiple categories, the element, and the category associated with the element. The selection can be performed by a user or automatically. 
     The user interface can be associated with a native application. When the user interface is associated with the native application, the processor can determine multiple categories associated with the user interface including controls and notifications. The processor can categorize the element associated with the user interface into a category among the multiple categories. The processor can enable a selection of the appropriate test by presenting the multiple categories, the element, and the category associated with the element. As mentioned above, the selection can be performed by a user or automatically. 
     The processor can test the performance of the program. The processor can obtain a program associated with the user interface and the indication of the appropriate test, where the appropriate test includes the audio test. The processor can execute the program associated with the user interface and the audio test. The processor can perform natural language processing on the audio test to determine whether the audio test corresponds to an output indicated in the appropriate test. Upon determining that the audio test does not correspond to the output indicating the appropriate test, the processor can indicate that the program did not pass the test. 
     Computer System 
       FIG.  6    is a block diagram that illustrates an example of a computer system  600  in which at least some operations described herein can be implemented. As shown, the computer system  600  can include: one or more processors  602 , main memory  606 , non-volatile memory  610 , a network interface device  612 , a video display device  618 , an input/output device  620 , a control device  622  (e.g., keyboard and pointing device), a drive unit  624  that includes a storage medium  626 , and a signal generation device  630  that are communicatively connected to a bus  616 . The bus  616  represents one or more physical buses and/or point-to-point connections that are connected by appropriate bridges, adapters, or controllers. Various common components (e.g., cache memory) are omitted from  FIG.  6    for brevity. Instead, the computer system  600  is intended to illustrate a hardware device on which components illustrated or described relative to the examples of the Figures and any other components described in this specification can be implemented. 
     The computer system  600  can take any suitable physical form. For example, the computer system  600  can share a similar architecture as that of a server computer, personal computer (PC), tablet computer, mobile telephone, game console, music player, wearable electronic device, network-connected (“smart”) device (e.g., a television or home assistant device), AR/VR systems (e.g., head-mounted display), or any electronic device capable of executing a set of instructions that specify action(s) to be taken by the computer system  600 . In some implementations, the computer system  600  can be an embedded computer system, a system-on-chip (SOC), a single-board computer system (SBC), or a distributed system such as a mesh of computer systems, or it can include one or more cloud components in one or more networks. Where appropriate, one or more computer systems  600  can perform operations in real time, near real time, or in batch mode. 
     The network interface device  612  enables the computer system  600  to mediate data in a network  614  with an entity that is external to the computer system  600  through any communication protocol supported by the computer system  600  and the external entity. Examples of the network interface device  612  include a network adapter card, a wireless network interface card, a router, an access point, a wireless router, a switch, a multilayer switch, a protocol converter, a gateway, a bridge, a bridge router, a hub, a digital media receiver, and/or a repeater, as well as all wireless elements noted herein. 
     The memory (e.g., main memory  606 , non-volatile memory  610 , machine-readable medium  626 ) can be local, remote, or distributed. Although shown as a single medium, the machine-readable medium  626  can include multiple media (e.g., a centralized/distributed database and/or associated caches and servers) that store one or more sets of instructions  628 . The machine-readable (storage) medium  626  can include any medium that is capable of storing, encoding, or carrying a set of instructions for execution by the computer system  600 . The machine-readable medium  626  can be non-transitory or comprise a non-transitory device. In this context, a non-transitory storage medium can include a device that is tangible, meaning that the device has a concrete physical form, although the device can change its physical state. Thus, for example, non-transitory refers to a device remaining tangible despite this change in state. 
     Although implementations have been described in the context of fully functioning computing devices, the various examples are capable of being distributed as a program product in a variety of forms. Examples of machine-readable storage media, machine-readable media, or computer-readable media include recordable-type media such as volatile and non-volatile memory devices  610 , removable flash memory, hard disk drives, optical disks, and transmission-type media such as digital and analog communication links. 
     In general, the routines executed to implement examples herein can be implemented as part of an operating system or a specific application, component, program, object, module, or sequence of instructions (collectively referred to as “computer programs”). The computer programs typically comprise one or more instructions (e.g., instructions  604 ,  608 ,  628 ) set at various times in various memory and storage devices in computing device(s). When read and executed by the processor  602 , the instruction(s) cause the computer system  600  to perform operations to execute elements involving the various aspects of the disclosure. 
     Remarks 
     The terms “example,” “embodiment,” and “implementation” are used interchangeably. For example, references to “one example” or “an example” in the disclosure can be, but not necessarily are, references to the same implementation; and, such references mean at least one of the implementations. The appearances of the phrase “in one example” are not necessarily all referring to the same example, nor are separate or alternative examples mutually exclusive of other examples. A feature, structure, or characteristic described in connection with an example can be included in another example of the disclosure. Moreover, various features are described which can be exhibited by some examples and not by others. Similarly, various requirements are described which can be requirements for some examples but no other examples. 
     The terminology used herein should be interpreted in its broadest reasonable manner, even though it is being used in conjunction with certain specific examples of the invention. The terms used in the disclosure generally have their ordinary meanings in the relevant technical art, within the context of the disclosure, and in the specific context where each term is used. A recital of alternative language or synonyms does not exclude the use of other synonyms. Special significance should not be placed upon whether or not a term is elaborated or discussed herein. The use of highlighting has no influence on the scope and meaning of a term. Further, it will be appreciated that the same thing can be said in more than one way. 
     Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise,” “comprising,” and the like are to be construed in an inclusive sense, as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to.” As used herein, the terms “connected,” “coupled,” or any variant thereof means any connection or coupling, either direct or indirect, between two or more elements; the coupling or connection between the elements can be physical, logical, or a combination thereof. Additionally, the words “herein,” “above,” “below,” and words of similar import can refer to this application as a whole and not to any particular portions of this application. Where context permits, words in the above Detailed Description using the singular or plural number may also include the plural or singular number respectively. The word “or” in reference to a list of two or more items covers all of the following interpretations of the word: any of the items in the list, all of the items in the list, and any combination of the items in the list. The term “module” refers broadly to software components, firmware components, and/or hardware components. 
     While specific examples of technology are described above for illustrative purposes, various equivalent modifications are possible within the scope of the invention, as those skilled in the relevant art will recognize. For example, while processes or blocks are presented in a given order, alternative implementations can perform routines having steps, or employ systems having blocks, in a different order, and some processes or blocks may be deleted, moved, added, subdivided, combined, and/or modified to provide alternative or sub-combinations. Each of these processes or blocks can be implemented in a variety of different ways. Also, while processes or blocks are at times shown as being performed in series, these processes or blocks can instead be performed or implemented in parallel, or can be performed at different times. Further, any specific numbers noted herein are only examples such that alternative implementations can employ differing values or ranges. 
     Details of the disclosed implementations can vary considerably in specific implementations while still being encompassed by the disclosed teachings. As noted above, particular terminology used when describing features or aspects of the invention should not be taken to imply that the terminology is being redefined herein to be restricted to any specific characteristics, features, or aspects of the invention with which that terminology is associated. In general, the terms used in the following claims should not be construed to limit the invention to the specific examples disclosed herein, unless the above Detailed Description explicitly defines such terms. Accordingly, the actual scope of the invention encompasses not only the disclosed examples, but also all equivalent ways of practicing or implementing the invention under the claims. Some alternative implementations can include additional elements to those implementations described above or include fewer elements. 
     Any patents and applications and other references noted above, and any that may be listed in accompanying filing papers, are incorporated herein by reference in their entireties, except for any subject matter disclaimers or disavowals, and except to the extent that the incorporated material is inconsistent with the express disclosure herein, in which case the language in this disclosure controls. Aspects of the invention can be modified to employ the systems, functions, and concepts of the various references described above to provide yet further implementations of the invention. 
     To reduce the number of claims, certain implementations are presented below in certain claim forms, but the applicant contemplates various aspects of an invention in other forms. For example, aspects of a claim can be recited in a means-plus-function form or in other forms, such as being embodied in a computer-readable medium. A claim intended to be interpreted as a means-plus-function claim will use the words “means for.” However, the use of the term “for” in any other context is not intended to invoke a similar interpretation. The applicant reserves the right to pursue such additional claim forms in either this application or a continuing application.