Patent Publication Number: US-11651769-B2

Title: Electronic device and operating method thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based on and claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2019-0113010, filed on Sep. 11, 2019, in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety. 
     BACKGROUND 
     1. Field 
     Various embodiments of the disclosure relate to an electronic device and an operating method thereof, and more particularly, to an electronic device for detecting voice activity detection with respect to a user&#39;s utterance and an operating method thereof. 
     2. Description of the Related Art 
     Voice recognition refers to a process of converting an audio signal obtained through a sound sensor such as a microphone into text data such as words or a sentence. As the numbers of devices and services for providing voice recognition are increasing, voice recognition has been used in various forms in various places. 
     A voice recognition system performs voice activity detection (VAD) to distinguish between an utterance section and a non-utterance section in an audio signal before performing voice recognition. For example, because it is not necessary to perform voice recognition with respect to a non-utterance section of the audio signal in which a user did not utter, voice recognition is performed only with respect to an utterance section detected through VAD. 
     The voice recognition system performs VAD by applying an average parameter value obtained as a result of analyzing people&#39;s utterances in general. In this case, a VAD error occurs in the case of a user with a relatively low or high utterance rate. 
     SUMMARY 
     Various embodiments of the disclosure provide an electronic device capable of changing a parameter for performing voice activity detection according to a user&#39;s utterance characteristics and an operating method thereof. 
     Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments of the disclosure. 
     According to an embodiment of the disclosure, an electronic device includes a memory storing one or more instructions; and a processor configured to execute the one or more instructions stored in the memory receive audio data corresponding to a user&#39;s utterance, to identify the user&#39;s utterance characteristics based on the received audio data, to determine a parameter for performing voice activity detection by using the identified user&#39;s utterance characteristics, and to perform voice activity detection one the received audio data with respect to the user&#39;s utterance by using the determined parameter. 
     In one embodiment of the disclosure, the audio data may include an utterance section corresponding to a trigger word uttered by the user. 
     In one embodiment of the disclosure, the determining of a parameter comprises comparing the user&#39;s utterance characteristics with reference utterance characteristics with respect to the trigger word, and changing the parameter based on a result of the comparing of. 
     In one embodiment of the disclosure, the identifying of the user&#39;s utterance characteristics comprises identifying the user&#39;s utterance characteristics based on the received audio data when the audio data includes an utterance section corresponding to the trigger word. 
     In one embodiment of the disclosure, the performing of voice activity detection may include detecting a start point of the user&#39;s utterance on the received audio data and an end point of the user&#39;s utterance on the received audio data while the user is uttering to distinguish between an utterance section of the receive audio data and a non-utterance section of the received audio data. 
     In one embodiment of the disclosure, the identified user&#39;s utterance characteristics may include at least one of the user&#39;s utterance rate, utterance energy level or pitch of uttered sound. 
     In one embodiment of the disclosure, the parameter for performing voice activity detection may include one or more of an energy threshold for identifying, on the received audio data, an utterance section, a hangover time, or automatic end time while the user is uttering. 
     In one embodiment of the disclosure, the electronic device may further include a communicator configured to receive the audio data corresponding to the user&#39;s utterance. 
     In one embodiment of the disclosure, the electronic device may further include a microphone configured to receives the user&#39;s utterance and to convert the user&#39;s utterance into the audio data. 
     According to another embodiment of the disclosure, an operating method of an electronic device includes receiving audio data corresponding to a user&#39;s utterance; identifying the user&#39;s utterance characteristics based on the received audio data; determining a parameter for performing voice activity detection, by using the identified user&#39;s utterance characteristics; and performing voice activity detection on the received audio data with respect to the user&#39;s utterance by using the determined parameter. 
     The identifying of the user&#39;s utterance characteristics comprises identifying the user&#39;s utterance characteristics based on the received audio data when the audio data includes an utterance section corresponding to a trigger word uttered by the user. 
     The determining of the parameter for performing voice activity detection comprises comparing the identified user&#39;s utterance characteristics with reference utterance characteristics with respect to the trigger word. 
     The identifying of the user&#39;s utterance characteristics comprises identifying the user&#39;s utterance characteristics based on the audio data when the audio data comprises the utterance section corresponding to the trigger word. 
     The performing of voice activity detection comprises detecting a start point of the user&#39;s utterance and an end point of the user&#39;s utterance while the user is uttering to distinguish between an utterance section of the received audio data and a non-utterance section of the received audio data. 
     The determining of the parameter comprises determining the parameter for performing voice activity detection based on at least one of the user&#39;s utterance rate, utterance energy level, or pitch of uttered sound. 
     The parameter for performing voice activity detection comprises at least one of an energy threshold for identifying an utterance section, a hangover time, or an automatic end time while the user is uttering. 
     The receiving of the audio data of the user&#39;s utterance comprises receiving the audio data corresponding to the user&#39;s utterance through a communicator. 
     The receiving of the audio data of the user&#39;s utterance comprises receiving the user&#39;s utterance through a microphone and converting the user&#39;s utterance into the audio data. 
     A non-transitory computer-readable recording media having recorded thereon a program for executing in a computer the operating method of claim  10 . 
     The processor is further configured to execute to perform the voice activity detection based on the changed user&#39;s utterance characteristics. The performing of voice activity detection further comprises performing the voice activity detection based on the changed user&#39;s utterance characteristics. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects, features, and advantages of certain embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which: 
         FIG.  1    is a diagram illustrating an electronic device according to an embodiment of the disclosure; 
         FIG.  2 A  is a diagram for describing an example in which an error occurs when voice activity detection is performed with respect to audio data of a user&#39;s utterance; 
         FIG.  2 B  is a diagram for describing another example in which an error occurs when voice activity detection is performed with respect to audio data of a user&#39;s utterance; 
         FIG.  3    is a block diagram of an electronic device according to an embodiment of the disclosure; 
         FIGS.  4 A and  4 B  are diagrams for describing a method of analyzing audio data corresponding to a trigger word, according to an embodiment of the disclosure; 
         FIG.  5    is a flowchart of an operating method of an electronic device, according to an embodiment of the disclosure; 
         FIG.  6    is a flowchart of an operating method of an electronic device, according to another embodiment of the disclosure; 
         FIG.  7    is a diagram for describing a method of changing a parameter for performing voice activity detection, based on a user&#39;s utterance characteristics, the method being performed by an electronic device, according to an embodiment of the disclosure; 
         FIG.  8    is a diagram for describing a method of changing a parameter for performing voice activity detection, by using a database including user information, the method being performed by an electronic device, according to an embodiment of the disclosure; 
         FIG.  9    is a diagram illustrating a voice recognition system according to an embodiment of the disclosure; 
         FIG.  10    is a block diagram of an electronic device according to an embodiment of the disclosure; and 
         FIG.  11    is a block diagram of an electronic device according to another embodiment of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The terms used in the present specification will be briefly described and then the disclosure will be described in detail. 
     In the disclosure, general terms that have been widely used nowadays are selected, when possible, in consideration of functions of the disclosure, but non-general terms may be selected according to the intentions of technicians in the this art, precedents, or new technologies, etc. Some terms may be arbitrarily chosen by the present applicant. In this case, the meanings of these terms will be explained in corresponding parts of the disclosure in detail. Thus, the terms used herein should be defined not based on the names thereof but based on the meanings thereof and the whole context of the disclosure. 
     It will be understood that when an element is referred to as “including” another element, the element may further include other elements unless mentioned otherwise. Terms such as “unit”, “module,” and the like, when used herein, represent units for processing at least one function or operation, which may be implemented by hardware, software, or a combination of hardware and software. 
     In embodiments of the disclosure, the term “user” refers to a viewer watching an image displayed on an electronic device or a person controlling a function or operation of the electronic device and may include an administrator or an installation engineer. 
     Hereinafter, embodiments of the disclosure will be described in detail with reference to the accompanying drawings, so that the embodiments of the disclosure may be easily implemented by those of ordinary skill in the art. However, the disclosure may be embodied in many different forms and is not limited to the embodiments of the disclosure set forth herein. For clarity, parts not related to explaining the disclosure are omitted in the drawings, and like components are denoted by like reference numerals throughout the specification. 
       FIG.  1    is a diagram illustrating an electronic device according to an embodiment of the disclosure. 
     Referring to  FIG.  1   , an electronic device  100  according to an embodiment of the disclosure may be embodied as various types of electronic devices, such as a TV, a set-top box, a mobile phone, a speaker, a tablet PC, a digital camera, a camcorder, a laptop computer, a desktop computer, an e-book terminal, a digital broadcasting terminal, a personal digital assistant (PDA), a portable multimedia player (PMP), a navigation device, an MP3 player, an Internet protocol television (IPTV), a digital Television (DTV), a wearable device, and the like. Alternatively, the electronic device  100  according to the embodiment of the disclosure may be a household appliance such as a refrigerator, a washing machine, an air conditioner, a vacuum, a light bulb, or an air purifier. Alternatively, the electronic device  100  may be a fixed electronic device provided at a fixed position or a mobile electronic device having a portable form or may be a digital broadcast receiver capable of receiving digital broadcasting services. 
     In one embodiment of the disclosure, a control device  200  may be embodied as various types of devices, such as a remote control or a cellular phone, for control of the electronic device  100 . An application for controlling the electronic device  100  may be installed in the control device  200 , and the control device  200  may control the electronic device  100  by using the installed application. However, embodiments of the disclosure are not limited thereto. In addition, the control device  200  may control the electronic device  100  by using Infrared (IR), Bluetooth (BT), W-Fi, or the like. 
     A user may speak or utter to the electronic device  100 . The user&#39;s utterance may include natural language instructing the electronic device  100  to perform a certain function (e.g., to control operations of hardware/software components included in the electronic device  100 , content search, etc.). 
     In one embodiment of the disclosure, the electronic device  100  may convert a user&#39;s utterance into an audio signal (audio data), which is an electrical signal, using an internal or external audio input module (e.g., a microphone). 
     A user may utter to the control device  200 , and the control device  200  may convert the user&#39;s utterance into an audio signal (audio data), which is an electrical signal, using an internal or external microphone. The control device  200  may transmit the audio signal to the electronic device  100 , and the electronic device  100  may receive the audio signal corresponding to the user&#39;s utterance from the control device  200  through a communication module. 
     In one embodiment of the disclosure, when a trigger word (or a wakeup word) is identified or a predetermined input is received, the electronic device  100  may start voice recognition with respect to the audio signal. The predetermined input may be an input for pressing a physical button included in the electronic device  100  or an input for selecting a graphic interface (e.g., an icon or the like) displayed on the electronic device  100  or a display of the electronic device  100 . Alternatively, the predetermined input may be an input for selecting a physical button included in the control device  200  communicating with the electronic device  100  or an input for selecting a graphic interface displayed on a display of an external device. 
     When voice recognition is started for the audio signal, the electronic device  100  according to an embodiment of the disclosure may perform voice activity detection by analyzing the audio signal of the user&#39;s utterance. Voice activity detection refers to a process of distinguishing between a voice section and a silent section from an audio signal of a user&#39;s utterance by detecting the start and end of the utterance while the user is uttering. 
     Accordingly, the audio signal or audio data corresponding to the silent section is not processed to minimize use of resources by the electronic device  100 . Alternatively, when voice recognition is performed with respect to the audio signal or the audio data by an external server or an external device, the audio signal or audio data corresponding to the silent section may not be transmitted to the external server or external device so as to reduce network traffic. 
     In one embodiment of the disclosure, the electronic device  100  may divide audio data of a user&#39;s utterance into a plurality of frames and identify whether each of the plurality of frames is a voice section or a non-voice section. For example, the electronic device  100  may identify whether each of the plurality of frames is a voice section or a non-voice section, based on an utterance energy threshold, a hangover time, an automatic end time, etc. The electronic device  100  may identify that a frame corresponds to a voice section when an utterance energy level corresponding to the frame is greater than or equal to a threshold, and identify that the frame corresponds to a non-voice section when the utterance energy level corresponding to the frame is less than the threshold. Alternatively, the electronic device  100  may determine that the utterance has ended when the non-utterance section continues for the hangover time or longer. When an utterance end point is not detected, the electronic device  100  may determine that the utterance has ended when an automatic end time has elapsed. However, embodiments of the disclosure are not limited thereto. 
       FIG.  2 A  is a diagram for describing an example in which an error occurs when voice activity detection is performed with respect to audio data of a user&#39;s utterance, and  FIG.  2 B  is a diagram for describing another example in which an error occurs when voice activity detection is performed with respect to audio data of a user&#39;s utterance. 
       FIG.  2 A  illustrates audio data  210  when a user having a relatively slow utterance rate utters. 
     When a set hangover time has elapsed, a voice activity detector determines that an utterance has ended. When the user&#39;s utterance rate is low, a time period between one word and another word (a time period until a subsequent word is spoken after a word is spoken) becomes longer than the set hangover time and thus it may be determined that an utterance has ended although the utterance does not end. For example, as illustrated in  FIG.  2 A , the user&#39;s actual utterance start point is P1, an actual utterance end point is P2, and an actual voice section (utterance section) is T1, but the voice activity detector may determine that the user&#39;s utterance start point is P3, an utterance end point is P4, and the user&#39;s voice section (utterance section) is T2. Accordingly, the user&#39;s utterance may be lost. 
     Alternatively, when a set automatic end time has elapsed, the voice activity detector determines that the utterance has ended. When the user&#39;s utterance rate is high, it may be determined that the utterance has ended after a long time even though the utterance has already been ended. For example, as illustrated in  FIG.  2 B , the user&#39;s actual utterance start point is P5, an actual utterance end point is P6, and an actual voice section (utterance section) is T3, but the voice activity detector may determine that the user&#39;s utterance start point is P7, an utterance end point is P8, and the user&#39;s voice section (utterance section) is T4. Accordingly, an unnecessary waiting time may occur. 
     When voice activity detection is performed by applying the same parameter without considering the user&#39;s utterance characteristics, the accuracy and efficiency of voice activity detection may low. 
       FIG.  3    is a block diagram of an electronic device according to an embodiment of the disclosure. 
     Referring to  FIG.  3   , the electronic device  100  according to an embodiment of the disclosure may include a voice inputter  310 , a voice activity detector (VAD)  320 , a trigger word identifier  330  and a trigger word analyzer  340 . 
     The voice inputter  310  may receive audio data of a user&#39;s utterance. For example, when the electronic device  100  receives the user&#39;s utterance through the internal or external audio input module (e.g., a microphone), the electronic device  100  may receive the audio data of the user&#39;s utterance from the internal or external audio input module. Alternatively, when the user&#39;s utterance is received using an internal or external microphone of an external device, the voice inputter  310  may receive the audio data from the external device through a communication module. 
     The voice inputter  310  may perform pre-processing to attenuate or remove noise from the audio data. 
     The voice activity detector  310  may detect a start point and an end point of the user&#39;s utterance by dividing the audio data of the user&#39;s utterance into a voice section (utterance section) containing the user&#39;s voice and a non-utterance section (non-utterance section or silence section) not containing the user&#39;s voice. The voice activity detector  310  may divide the audio data into a plurality of frames and identify whether each of the plurality of frames corresponds to a voice section or a non-voice section. 
     The voice activity detector  310  may distinguish between a voice section and a non-voice section, based on parameters which are set in the voice activity detector  310 . For example, the voice activity detector  310  may identify whether each of the plurality of frames is a voice section or a non-voice section, based on parameters such as an utterance energy threshold, a hangover time, an automatic end time, and the like. The voice activity detector  310  may identify that a frame is a voice section when an utterance energy level corresponding to the frame is greater than or equal to a threshold, and identify that the frame is a non-voice section when the utterance energy level corresponding to the frame is less than the threshold. 
     Alternatively, the voice activity detector  310  may determine that the utterance has ended when the non-voice section continues for the hangover time or longer. When an utterance end point is not detected, the voice activity detector  310  may determine that the utterance has ended when an automatic end time has elapsed. 
     In addition, the voice activity detector  310  may perform a process of removing the non-utterance section from the user&#39;s audio data. 
     The trigger word identifier  330  may identify whether the user&#39;s utterance corresponds to a trigger word. For example, the trigger word identifier  330  may identify whether audio data of an utterance section detected by the VAD  320  corresponds to a trigger word. The trigger word is a word indicating the start of the utterance, and may be referred to as a wakeup word, an utterance start word, or the like but is not limited thereto. 
     The trigger word may be set in advance, and the trigger word recognizer  330  may include an isolated word identifier that searches for a word with a maximum probability, a keyword search engine that searches for a preset keyword of the audio data. 
     Alternatively, the trigger word identifier  330  may perform a process of obtaining the audio data of the utterance section in the form of text or words and identify whether text or words obtained as a result of the processing corresponds to a trigger word. 
     The trigger word analyzer  340  may analyze the user&#39;s utterance corresponding to a trigger word to identify the user&#39;s utterance characteristics. The trigger word analyzer  340  may analyze an utterance energy level and rate of a voice section corresponding to the trigger word to identify the user&#39;s utterance characteristics. The trigger word analyzer  340  may change settings of the parameters of the VAD  320 , based on the user&#39;s utterance characteristics. 
     For example, the trigger word analyzer  340  may compare an utterance rate (or utterance time) of a user who utters a trigger word with a reference utterance rate (or reference utterance time) to change a hangover time used for voice activity detection. In this case, the reference utterance rate is a preset value and may be an average value of utterance rates of general people. 
     Alternatively, an utterance energy level of a user who utters a trigger word may be compared with a reference utterance energy level to change an utterance energy threshold used for voice activity detection. In this case, the reference utterance energy level may be an average value of utterance energy levels of various people. 
     The trigger word analyzer  340  may calculate values Vc and Ec by using Equation 1 below. 
     
       
         
           
             
               
                 
                   
                     
                       V 
                       c 
                     
                     = 
                     
                       
                         t 
                         avg 
                       
                       
                         t 
                         trigger 
                       
                     
                   
                   , 
                   
                     
                       E 
                       c 
                     
                     = 
                     
                       
                         e 
                         avg 
                       
                       
                         e 
                         trigger 
                       
                     
                   
                 
               
               
                 
                   [ 
                   
                     Equation 
                     ⁢ 
                         
                     1 
                   
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     Here, Vc represents a ratio between a reference utterance time t avg  (a statistically calculated average time during which a trigger word is uttered) and an utterance time t trigger  for a user to utter the trigger word. Ec represents a ratio between a reference utterance energy level e avg  (a statistically calculated average utterance energy level for uttering the trigger word) and an utterance energy level e trigger  for the user to utter the trigger word. 
     The trigger word analyzer  340  may change parameters such as a hangover time of the VAD  320 , the utterance energy threshold, and the like, based on the values Vc and Ec. 
     For example, the trigger word analyzer  340  may change the hangover time by using the value Vc. When the user&#39;s utterance rate is low, the value Vc decreases, and as the value Vc decreases, the hangover time may be changed to be increased. On the other hand, when the user&#39;s utterance rate is high, the value Vc increases, and as the value Vc increases, the hangover time may be changed to be reduced. This will be described in detail with reference to  FIG.  4    below. 
     In addition, the trigger word analyzer  340  may change the utterance energy threshold by using the value Ec. When the user&#39;s utterance energy level is low, the value Ec increases, and as the value Ec increases, the utterance energy threshold may be changed to be reduced. On the other hand, when the user&#39;s utterance energy level is high, the value Ec decreases, and as the value Ec decreases, the utterance energy threshold may be changed to be increased. Accordingly, when a user with a low utterance energy level utters, a lower utterance energy threshold is reduced to prevent the user&#39;s utterance from being identified as noise, and when a user with a high utterance energy level utters, a higher utterance energy threshold is increased to prevent the user&#39;s utterance from being identified as noise. 
     The trigger word analyzer  340  may variably set a size of a window (e.g., a Hamming window) used to analyze a user&#39;s utterance characteristics, such as the user&#39;s utterance rate or utterance energy level, based on the user&#39;s utterance characteristics. For example, when the user&#39;s utterance rate is high, the size of the window may be reduced, and when the user&#39;s utterance rate is low, the size of the window may be increased to analyze the user&#39;s utterance characteristics. 
     In addition, the trigger word analyzer  340  may change settings of the parameters of the VAD  320 , based on a pitch of sound uttered by a user who utters a trigger word, a signal-to-noise ratio, a zero-crossing rate Z, a result of analyzing a spectrum, and the like. 
       FIGS.  4 A and  4 B  are diagrams for describing a method of analyzing audio data corresponding to a trigger word, according to an embodiment of the disclosure. 
       FIGS.  4 A and  4 B  illustrate audio data corresponding to trigger words when different users utter the trigger word. 
     Referring to  FIGS.  4 A and  4 B , first audio data  410  represents audio data corresponding to a trigger word when a first user utters the trigger word, and second audio data  420  represents audio data corresponding to the trigger word when a second user utters the trigger word that the first user utters. 
     A length of an utterance section in which a trigger word is spoken may vary according to a user, and when voice activity detection is performed using the same parameters, the accuracy and efficiency of voice activity detection may be low as described above with reference to  FIGS.  2 A and  2 B . 
     In one embodiment of the disclosure, the trigger word analyzer  340  may calculate a first utterance time T1(=Te1−Ts1) by detecting an utterance start point Ts1 and an utterance end point Te1 from the first audio data  414 . 
     The trigger word analyzer  340  may calculate a ratio Vc1 between a reference utterance time T0 during which a trigger word is spoken and a first user&#39;s first utterance time T1, and change a hangover time of the VAD  320 , based on the ratio Vc1. In this case, the reference utterance time T0 may be an utterance time during which ordinary people utter the trigger word. 
     For example, when the hangover time of the VAD  320  is set to an average hangover time T h , the hangover time may be changed to Th/Vc1. 
     Accordingly, when an utterance rate of the first user is higher than a reference utterance rate, the ratio Vc1 is greater than 1 and the hangover time reduces and thus a time required to determine the utterance end point Te1 may be reduced. Accordingly, an unnecessary waiting time may be reduced when a user having a high utterance rate utters. 
     In addition, the trigger word analyzer  340  may calculate a second utterance time T2(=Te2−Ts1) by detecting an utterance start point Ts1 and an utterance end point Te2 in the second audio data  420 . 
     The trigger word analyzer  340  may calculate a ratio Vc2 between the reference utterance time T0 and the second user&#39;s second utterance time T2, and change the hangover time of the VAD  320 , based on the ratio Vc2. For example, when the hangover time of the VAD  320  is set to an average hangover time T h , the hangover time may be changed to Th/Vc2. 
     Accordingly, when an utterance rate of the second user is lower than the reference utterance rate, the ratio Vc2 is less than 1 and the hangover time increases and thus a time required to determine the utterance end point Te2 may be increased. Accordingly, when a user having a low utterance rate utters, a silent section between words may not be determined as an utterance end point even when the silent section is relatively long. Accordingly, when the user having the low utterance rate utters, loss of the utterance may be prevented. 
       FIG.  5    is a flowchart of an operating method of an electronic device, according to an embodiment of the disclosure. 
     Referring to  FIG.  5   , the electronic device  100  according to an embodiment of the disclosure may obtain audio data of a user&#39;s utterance (S 510 ). The electronic device  100  may obtain audio data by receiving the user&#39;s utterance through an audio input module or obtain audio data of the user&#39;s utterance from an external device through a communication module. However, embodiments of the disclosure are not limited thereto. 
     In addition, when a trigger word is identified or a predetermined input is received, the electronic device  100  may start voice recognition with respect to audio data. 
     In one embodiment of the disclosure, when voice recognition is started for the audio signal, the electronic device  100  may perform voice activity detection by analyzing the audio signal of the user&#39;s utterance. 
     The electronic device  100  may identify the user&#39;s utterance characteristics, based on a voice section detected from the audio data of the user&#39;s utterance (S 520 ). 
     The user&#39;s utterance characteristics may include, but are not limited to, the user&#39;s utterance energy, an utterance rate, an utterance time, a pitch of the utterance, and the like. 
     For example, when the user utters a pre-set keyword, the electronic device  100  may analyze the user&#39;s utterance characteristics by measuring the user&#39;s utterance energy, an utterance rate, an utterance time, a pitch of uttered sound, and the like and comparing them with reference values (e.g., an average utterance energy level, an average utterance rate, an average utterance time, an average pitch of uttered sound, etc.) of the pre-set keyword. 
     In this case, the reference values of the pre-set keyword may be stored in advance in the electronic device  100  or obtained from an external device. The pre-set keyword according to an embodiment of the disclosure may be, but is not limited to, a trigger word, a wakeup word, an utterance start word, or the like which indicates the start of the utterance. 
     The electronic device  100  may change parameters for voice activity detection, based on the user&#39;s utterance characteristics (S 530 ). 
     The electronic device  100  may change parameters for performing voice activity detection (e.g., an utterance energy threshold, an utterance rate threshold, an uttered-sound pitch threshold, a hangover time, an automatic end time, a size of a window for utterance analysis, etc.), based on the user&#39;s utterance energy level, utterance rate, utterance time, and uttered-sound pitch. 
     The electronic device  100  may perform voice activity detection with respect to audio data of the user&#39;s utterance by using the changed parameters (S 540 ). 
       FIG.  6    is a flowchart of an operating method of an electronic device, according to another embodiment of the disclosure. 
     Referring to  FIG.  5   , the electronic device  100  according to an embodiment of the disclosure may receive audio data of a user&#39;s utterance (S 610 ). 
     For example, when the electronic device  100  receives the user&#39;s utterance through an internal or external audio input module (e.g., a microphone), the electronic device  100  may receive the audio data of the user&#39;s utterance from the internal or external audio input module. Alternatively, when the user&#39;s utterance is received using an internal or external microphone of an external device, the electronic device  100  may receive the audio data from the external device through a communication module (communicator). 
     The electronic device  100  may perform voice activity detection with respect to the audio data (S 620 ). 
     The electronic device  100  may distinguish between a voice section (utterance section) and a non-voice section (non-utterance section) from the audio data, based on pre-set parameters. For example, the electronic device  100  may identify whether each of a plurality of frames included in the audio data corresponds to a voice section or a non-voice section, based on parameters such as an utterance energy threshold, a hangover time, an automatic end time, and the like. The electronic device  100  may identify that a frame is a voice section when an utterance energy level corresponding to the frame is greater than or equal to a threshold, and may identify that the frame is a non-voice section when the utterance energy level corresponding to the frame is less than the threshold. 
     Alternatively, the electronic device  100  may determine that the utterance has ended when the non-voice section continues for a set hangover time or longer. When an utterance end point is not detected, the electronic device  100  may determine that the utterance has ended when an automatic end time has elapsed. 
     The electronic device  100  may identify whether audio data of an utterance section identified as a voice section corresponds to a trigger word (S 630 ). The trigger word is a word indicating the start of the utterance, and may be referred to as a wakeup word, an utterance start word, or the like but is not limited thereto. 
     When the audio data is identified as the trigger word, the electronic device  100  may analyze the user&#39;s utterance corresponding to the trigger word to identify the user&#39;s utterance characteristics (S 640 ). For example, the electronic device  100  may analyze the user&#39;s utterance characteristics by comparing an utterance energy level, utterance rate, utterance time, pitch of uttered sound, etc. of the user who utters the trigger word with reference values of the trigger word (e.g., an average utterance energy level, an average utterance rate, an average utterance time, an average pitch of uttered sound, etc. when general people utter the trigger word). 
     The electronic device  100  may change settings of a voice activity detector, based on the user&#39;s utterance characteristics (S 650 ). For example, the electronic device  100  may change parameters for performing voice activity detection (e.g., an utterance energy threshold, an utterance rate threshold, an uttered-sound pitch threshold, a hangover time, an automatic end time, a size of a window for utterance analysis, etc.), based on the user&#39;s utterance energy level, utterance rate, utterance time, and uttered-sound pitch. 
     When the user&#39;s free utterance is input after the trigger word is received (S 660 ), the electronic device  100  may perform voice activity detection with respect to the user&#39;s free utterance by using the changed parameters (S 670 ). 
       FIG.  7    is a diagram for describing a method of changing a parameter for performing voice activity detection, based on a user&#39;s utterance characteristics, the method being performed by an electronic device, according to an embodiment of the disclosure. 
     Referring to  FIG.  7   , the electronic device  100  according to an embodiment of the disclosure may receive a certain keyword to determine a user&#39;s utterance characteristics. 
     For example, when a user utters a trigger word or performs a predetermined input, the electronic device  100  displays on the display thereof a message  710  instructing to utter the keyword (e.g., “Hello ABC”). The predetermined input may be an input for pressing a physical button included in the electronic device  100  or the control device  200  controlling the electronic device  100  or may be an input for selecting a graphic interface (e.g., an icon) displayed on the display of the electronic device  100  or a display of the control device  200 . 
     The keyword is a keyword preset in the electronic device  100  and is a combination of simple words rather than a long sentence. Alternatively, the electronic device  100  may store reference utterance characteristics (e.g., an utterance energy level, an utterance rate, an utterance time, a pitch of uttered sound, etc.) corresponding to the keyword. In this case, the reference utterance characteristics corresponding to the keyword may refer to an average utterance energy, an average utterance rate, an average utterance time, an average pitch of uttered sound, etc. when general people utter the keyword. 
     The user may utter the keyword (e.g., “Hello ABC”) in response to the displayed message. The user may utter to the electronic device  100  or the control device  200 . When the user utters to the electronic device  100 , the electronic device  100  may receive audio data of the user&#39;s utterance through the audio input module. When the user utters to the control device  200 , the electronic device  100  may receive audio data of the user&#39;s utterance through the communication module. 
     The electronic device  100  may detect a voice section by performing voice activity detection with respect to the received audio data and identify whether the keyword is included in the voice section to obtain the user&#39;s utterance characteristics for the keyword. For example, the electronic device  100  may obtain utterance characteristics (e.g., an utterance energy level, an utterance rate, an utterance time, a pitch of uttered sound, etc.) of the user who utters the keyword. 
     The electronic device  100  may compare the obtained user&#39;s utterance characteristics with reference utterance characteristics to change parameters for performing voice activity detection (e.g., an utterance energy threshold, an utterance rate threshold, an uttered-sound pitch threshold, a hangover time, an automatic end time, a size of a window for utterance analysis, etc.). 
     The electronic device  100  may perform voice activity detection using the changed parameters while the user utters. For example, the electronic device  100  may perform voice activity detection using the changed parameter with respect to the user&#39;s free utterance which is input after the keyword is uttered. However, embodiments of the disclosure are not limited thereto. 
       FIG.  8    is a diagram for describing a method of changing parameters for performing voice activity detection, by using a database including user information, the method being performed by an electronic device, according to an embodiment of the disclosure. 
     Referring to  FIG.  8   , the electronic device  100  according to an embodiment of the disclosure may include a database  800  storing user information. The database  800  according to an embodiment of the disclosure may include at least one of user face information, user fingerprint information, voice activity detection parameters, or trigger word utterance characteristics (e.g., a trigger word utterance energy level, a trigger word utterance rate, etc.) corresponding to user identification information. 
     For example, when a first user logs in with his or her account information and utters a trigger word, the electronic device  100  may store the first user&#39;s trigger word utterance energy level and trigger word utterance rate as first user information in the database  800 . 
     Alternatively, the electronic device  100  may obtain the first user&#39;s face information by photographing the first user while the first user utters the trigger word, and store the obtained face information of the first user as first user information in the database  800 . 
     Alternatively, the electronic device  100  may receive the first user&#39;s fingerprint information through an external device or the like while the first user utters the trigger word, and store the received first user&#39;s fingerprint information as first user information in the database  800 . 
     Alternatively, the electronic device  100  may determine a first voice activity detection parameter, based on the first user&#39;s trigger word utterance energy level and trigger word utterance rate, and store the determined first voice activity detection parameter as first user information in the database  800 . 
     The electronic device  100  may also store in the database  800  user information of a second user to a fourth user in the same manner. 
     When the first user utters, the electronic device  100  may identify the first user by photographing the first user to perform face recognition or receiving an image of the first user&#39;s fingerprint to perform fingerprint recognition. In this case, even when the first user does not utter the trigger word, the parameters for performing voice activity detection may be changed, based on the first user&#39;s trigger word utterance energy level and trigger word utterance rate and the first voice activity detection parameter which are included in the first user information. 
     In addition, the electronic device  100  may store, in the database  800 , not only the utterance characteristics with respect to the trigger word but also utterance characteristics of the first user&#39;s previous utterance input, and change the parameters for performing voice activity detection, based on the utterance characteristics of the first user&#39;s previous utterance input. 
       FIG.  9    is a diagram illustrating a voice recognition system according to an embodiment of the disclosure. 
     Referring to  FIG.  9   , the voice recognition system according to an embodiment of the disclosure may include an electronic device  100  and a server  900 . The server  900  may be connected to the electronic device  100  through a network or short-range communication. In one embodiment of the disclosure, the server  900  may be a server that performs voice recognition. 
     In one embodiment of the disclosure, the electronic device  100  may receive audio data of a user&#39;s utterance. For example, the electronic device  100  may convert the user&#39;s utterance (analog signal) into an audio signal (digital signal) which is an electrical signal through an internal or external audio input module (e.g., a microphone), and transmit the audio signal to a processor. 
     Alternatively, when the user utters to the control device  200  according to an embodiment of the disclosure, the control device  200  may convert the user&#39;s utterance (analog signal) into an audio signal (digital signal) which is an electrical signal through an internal or external microphone. The control device  200  may transmit the audio signal to the electronic device  100  through a communication module such as a Bluetooth (BT) module. 
     The electronic device  100  may detect a voice section by performing voice activity detection with respect to the audio signal (audio data), and transmit the detected voice section to the server  900 . 
     In one embodiment of the disclosure, the server  900  may perform voice recognition on the voice section received from the electronic device  100 . The voice recognition may be a process of obtaining text data corresponding to the audio signal. The voice recognition may include a speech-to-text (STT) process. For example, the voice recognition may include a process of identifying a voice signal uttered by the user as a character string. Text obtained as a result of voice recognition may be in the form of a sentence, word or phrase in natural language. However, embodiments of the disclosure are not limited thereto. 
     The server  900  may identify whether a trigger word is included in the voice section through voice recognition. 
     When the trigger word is included in the voice section, the server  900  may analyze the user&#39;s utterance corresponding to the trigger word to identify the user&#39;s utterance characteristics. For example, the server  900  may analyze the user&#39;s utterance characteristics by comparing an utterance energy level, an utterance rate, an utterance time, pitch of uttered sound, etc. of the user who utters the trigger word with reference values of the trigger word (e.g., an average utterance energy level, an average utterance rate, an average utterance time, an average pitch of uttered sound, etc. when general people utter the trigger word). 
     The server  900  may transmit a result of analyzing the utterance characteristics to the electronic device  100 . 
     Alternatively, when the server  900  identifies whether the trigger word is included in the voice section and informs the electronic device  100  of a result of the identification, the electronic device  100  may analyze the user&#39;s utterance corresponding to the trigger word to identify the user&#39;s utterance characteristics. A method, performed by the electronic device  100 , of identifying a user&#39;s utterance characteristics by analyzing the user&#39;s utterance corresponding to a trigger word has been described above in detail with reference to  FIGS.  3  to  8    and thus a detailed description thereof is omitted here. 
     The electronic device  100  may change parameters for performing voice activity detection, based on the user&#39;s utterance characteristics, and when the user&#39;s free utterance is input after a trigger word is input, voice activity detection may be performed on the user&#39;s free utterance by using the changed parameters. 
     The electronic device  100  may transmit a voice section detected from the user&#39;s free utterance to the server  900 , and the server  900  may perform voice recognition on the user&#39;s free utterance and perform a certain function based on a result of the voice recognition. Alternatively, the result of the voice recognition may be transmitted to the electronic device  100  or another server (not shown). 
     When the electronic device  100  receives the result of the voice recognition, the electronic device  100  may perform a certain function corresponding to the result of the voice recognition. Alternatively, when another server receives the result of the voice recognition, the other server may perform a certain function based on the result of the voice recognition or control another electronic device to perform the function. 
     Alternatively, the electronic device  100  may perform voice recognition on the voice section detected from the free utterance and perform a certain function based on the result of the voice recognition. 
       FIG.  10    is a block diagram of an electronic device according to an embodiment of the disclosure. 
     Referring to  FIG.  10   , an electronic device  100  according to an embodiment of the disclosure may include a microphone  110 , a processor  120 , a memory  130 , and a communicator  140 . 
     The microphone  110  according to an embodiment of the disclosure may receive a sound signal from an external device or a speaker (a user of the electronic device  100 ). In one embodiment of the disclosure, the microphone  110  may receive a voice of a user&#39;s utterance. The microphone  110  may receive an external sound signal and convert the external sound signal into an electrical signal (audio data). The microphone  110  may use various noise removal algorithms to remove noise generated during the receiving of the external sound signal. 
     In one embodiment of the disclosure, the communicator  120  may transmit data or signals to or receive data or signals from an external device (e.g., a control device, a server, or the like) under control of the processor  120 . The communicator  140  may transmit and receive data or signals according to at least one method of a wireless LAN (e.g., Wi-Fi), Bluetooth, wired Ethernet, infrared (IR), Bluetooth Low Energy (BLE), ultrasound, or ZigBee to correspond to the performance and structure of the electronic device  100 . Here, the communicator  140  may include at least one communication module capable of transmitting and receiving data according to a communication standard corresponding to the wireless LAN (e.g., Wi-Fi), Bluetooth, wired Ethernet, IR, BLE, ultrasound and ZigBee. 
     In one embodiment of the disclosure, the communicator  140  may transmit data or signals to and receive data or signals from a control device or server by using the same communication module (e.g., a W-Fi module). Alternatively, in one embodiment of the disclosure, a module (e.g., a Bluetooth module or an IR module) for communicating with a control device and a module (e.g., an Ethernet module or a Wi-Fi module) for communicating with a server may be different from each other. 
     In one embodiment of the disclosure, the processor  120  may control overall operations of the electronic device  100 . In addition, the processor  120  may control other components included in the electronic device  100  to perform a certain operation. 
     In one embodiment of the disclosure, the processor  120  may execute one or more programs stored in the memory  130 . The processor  120  may include a single core, dual cores, triple cores, quad cores, and multiples thereof. The processor  120  may include a plurality of processors. 
     In one embodiment of the disclosure, the memory  130  may store various data, programs, or applications for driving and controlling the electronic device  100 . In addition, in one embodiment of the disclosure, the memory  130  may store user information as illustrated in and described above with reference to  FIG.  8   . For example, the memory  130  may store, as user information, at least one of user face information, user fingerprint information, voice activity detection parameters, or trigger word utterance characteristics corresponding to user identification information. 
     A program stored in the memory  130  may include one or more instructions. The program (one or more instructions) or an application stored in the memory  130  may be executed by the processor  120 . 
     In one embodiment of the disclosure, the processor  120  may obtain audio data of a user&#39;s utterance and perform voice activity detection with respect to the obtained audio data. The processor  120  may perform voice activity detection to detect a voice section (utterance section) in the audio data and identify the user&#39;s utterance characteristics, based on the detected voice section. For example, the processor  120  may identify whether the detected voice section corresponds to a preset keyword or trigger word. The processor  120  may analyze the user&#39;s utterance corresponding to the preset keyword or trigger word to identify the user&#39;s utterance characteristics. 
     The processor  120  may change parameters for performing voice activity detection, based on the user&#39;s utterance characteristics (e.g., an utterance energy level, an utterance rate, an utterance time, a pitch of uttered sound, etc.). For example, the processor  120  may change an utterance energy threshold, an utterance rate threshold, an uttered-sound pitch threshold, a hangover time, an automatic end time, a size of a window for analyzing an utterance and the like, based on the user&#39;s utterance characteristics. 
     In addition, the processor  120  may identify the user who is uttering, and identify the user&#39;s utterance characteristics or change the parameters for performing voice activity detection by using user information corresponding to the identified user. 
     The processor  120  may perform voice activity detection with respect to the user&#39;s utterance by using the changed parameters. 
       FIG.  11    is a block diagram of an electronic device  1000  according to another embodiment of the disclosure. 
     The electronic device  1000  of  FIG.  11    may correspond to the electronic device  100  according to an embodiment of the disclosure as described above with reference to  FIGS.  1  to  10   . 
     Referring to  FIG.  11   , the electronic device  1000  according to an embodiment of the disclosure includes a tuner  1040 , a processor  1010 , a display  1020 , a communicator  1050 , a detector  1030 , an inputter/outputter  1070 , a video processor  1080 , an audio processor  1085 , an audio outputter  1060 , a memory  1090 , and a power supply  1095 . 
     A microphone  1031  of  FIG.  11    corresponds to the microphone  110  of  FIG.  10   , the communicator  1050  of  FIG.  11    corresponds to the communicator  140  of  FIG.  10   , the processor  1010  of  FIG.  11    corresponds to the processor  120  of  FIG.  10   , and the memory  1090  of  FIG.  11    corresponds to the memory  130  of  FIG.  10   , and thus a detailed description thereof is omitted here. 
     In one embodiment of the disclosure, the tuner  1040  may tune and select only a frequency of a channel to be received by the electronic device  1000  from among various radio wave components by performing amplification, mixing, or resonance on a broadcast signal received via wire or wirelessly. The broadcast signal includes audio data, a video and additional information (e.g., an electronic program guide (EPG)). 
     The tuner  1040  may receive the broadcast signal from various sources such as terrestrial broadcasting, cable broadcasting, satellite broadcasting, Internet broadcasting, and the like. The tuner  1040  may receive the broadcast signal from a source such as analog broadcasting or digital broadcasting. 
     In one embodiment of the disclosure, the communicator  1050  may transmit data or signals to and receive data or signals from an external device or a server under control of the processor  1010 . The processor  1010  may transmit content to or receive content from an external device (not shown) connected thereto through the communicator  1050 , download an application from the external device, or perform web browsing. 
     In addition, the communicator  1050  may include a combination including one or more among a wireless LAN module  1051 , a Bluetooth module  1052 , and a wired Ethernet module  1053 . 
     The video processor  1080  processes video data received by the electronic device  1000 . The video processor  1080  may perform various image processing operations, such as decoding, scaling, noise filtering, frame rate conversion, resolution conversion, and the like, on the video data. 
     The detector  1030  may detect a user&#39;s voice, an image of the user or the user&#39;s interaction, and include the microphone  1031 , a camera  1032 , and an optical receiver  1033 . 
     The microphone  1031  receives the user&#39;s uttered voice. The microphone  1031  may convert received voice into an electric signal and output the electric signal to the processor  1010 . The user&#39;s voice may include, for example, voice corresponding to a menu or function of the electronic device  1000 . 
     The camera  1032  may receive an image (e.g., continuous frames) corresponding to a user&#39;s motion, including a gesture, within a camera recognition range. The controller  1010  may select a menu displayed on the electronic device  1000  by using a received result of recognition of a motion or may perform control corresponding to the result of recognition of the motion. 
     An optical receiver  1033  receives an optical signal (including a control signal) from an external control device through an optical window (not shown) of a bezel of the display  1020  or the like. The optical receiver  1033  may receive an optical signal corresponding to a user input (e.g., touching, pressing, a touch gesture, voice, or a motion) from a control device (not shown). The control signal may be extracted from the received optical signal under control of the processor  1010 . 
     The inputter/outputter  1070  receives a video (e.g., a moving picture), an audio signal (e.g., voice or music), additional information (e.g., an EPG) and the like from the outside of the electronic device  1000 , under control of the processor  1010 . Alternatively, the input/output unit  1070  transmits video, an audio signal, additional information, and the like to an external device under the control of the processor  1010 . The inputter/outputter  1070  may include one of a high-definition multimedia interface (HDMI) port  1071 , a component jack  1072 , a PC port  1073 , and a USB port  1074 . The inputter/outputter  1070  may include a combination of the HDMI port  1071 , the component jack  1072 , the PC port  1073 , and the USB port  1074 . In addition, the inputter/outputter  1070  may include a display port (DP), a thunderbolt port, and the like. 
     The processor  1010  controls overall operations of the electronic device  1000  and signal flow between internal components of the electronic device  1000 , and performs a data processing function. The processor  1010  may execute an operation system (OS) and various applications stored in the memory  1090  when there is a user input or a preset and stored condition is satisfied. 
     The processor  130  may include random access memory (RAM) to be used to store a signal or data which is input from the outside of the electronic device  1000  or used as a storage region corresponding to various operations performed by the electronic device  1000 , and read-only memory (ROM) to store a control program for control of the electronic device  1000 . 
     The processor  1010  may include a graphics processor (not shown). The graphics processor generates a screen including various objects, such as an icon, an image, and text, using an operation unit (not shown) and a renderer (not shown). The operation unit calculates attribute values, such as coordinates, a shape, a size, and color, of each object to be displayed according to a layout of the screen by using a user input detected by the detector  1030 . The renderer generates screens of various layouts including objects, based on the attribute values calculated by the operation unit. A screen generated by the renderer is displayed on a display region of the display  1020 . 
     The display  1020  generates a driving signal by converting an image signal, a data signal, an on-screen display (OSD) signal, a control signal or the like processed by the processor  130 . The display  1020  may be embodied as a plasma display panel (PDP), a liquid crystal panel (LCD), an organic light-emitting diode (OLED) display, a flexible display, or the like or may be embodied as a three-dimensional (3D) display. Alternatively, the display  1020  may be configured as a touch screen to be used as an input device, in addition to an output device. 
     The audio processor  1085  processes audio data. The audio processor  1085  may perform various operations, such as decoding, amplification, and noise filtering, on the audio data. The audio processor  1085  may include a plurality of audio processing modules to process audio data corresponding to a plurality of pieces of content. 
     The audio outputter  1060  outputs audio data included in a broadcast signal received through the tuner  1040  under control of the processor  1010 . The audio outputter  1060  may output audio data (e.g., voice or sound) input via the communicator  1050  or the inputter/outputter  1070 . The audio outputter  1060  may output audio data stored in the memory  1090  under control of the processor  1010 . The audio outputter  1060  may include at least one of a speaker  1061 , a headphone output terminal  1062 , or a Sony/Philips Digital Interface (S/PDIF) output terminal  1063 . The audio outputter  1060  may include a combination of the speaker  1061 , the headphone output terminal  1062  and the S/PDIF output terminal  1063 . 
     The power supply  1095  supplies power from an external power source to the internal components of the electronic device  1000  under control of the processor  1010 . Alternatively, the power supply  1095  supplies power output from one or more batteries (not shown) included in the electronic device  1000  to the internal components under control of the processor  1010 . 
     The memory  1090  may store various data, programs, or applications for driving and controlling the electronic device  1000  under control of the processor  1010 . Although not shown, the memory  1090  may include a broadcast receiving module, a channel control module, a volume control module, a communication control module, a voice recognition module, a motion recognition module, an optical receiving module, a display control module, an audio control module, an external input control module, a power control module, a power control module of an external device connected wirelessly (e.g., Bluetooth), a voice database (DB), or a motion database (DB). The modules and databases (not shown) of the memory  1090  may be embodied as software to perform by the electronic device  1000  a broadcast reception control function, a channel control function, a volume control function, a communication control function, a voice recognition function, a motion recognition function, and an optical reception control function, a display control function, an audio control function, an external input control function, a power control function, or a power control function of an external device connected wirelessly (e.g., Bluetooth). The processor  1010  may perform each of these functions by using the software stored in the memory  1090 . 
     The block diagrams of the electronic devices  100  and  1000  illustrated in  FIGS.  10  and  11    are only block diagrams according to embodiments of the disclosure. Some components of each of the block diagrams may be combined together or omitted or new components may be added thereto according to the specifications of the electronic devices  100  and  1000  that are actually implemented. That is, two or more components may be combined into one component or one component may be divided into two or more components as needed. A function performed in each block is only provided to explain embodiments of the disclosure and the scope of the disclosure should not be construed as being limited to specific operations or devices. 
     An operating method of an electronic device, according to an embodiment of the disclosure, may be embodied in the form of program commands executable through various computer means and recorded on a computer-readable recording medium. The computer-readable recording medium may include program commands, data files, data structures, and the like solely or in combination. The program commands recorded on this medium may be specially designed and configured for the disclosure or may be well-known and available to those of ordinary skill in the field of computer software. Examples of the computer-readable recording medium include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical media such as CD-ROMs and DVDs, magneto-optical media such as floptical disks, and hardware devices, such as ROMs, RAMs, and flash memory, which are specifically configured to store and execute program commands. Examples of the program commands include not only machine code generated by a compiler but also high-level language code executable by a computer using an interpreter or the like. 
     Operating methods of an electronic device according to the embodiments of the disclosure set forth herein may be provided by being included in a computer program product. A computer program product may be traded as a product between a seller and a purchaser. 
     The computer program product may include a software program and a computer-readable storage medium on which the software program is stored. For example, the computer program product may include a product (e.g., a downloadable application) in the form of a software program electronically distributed through a manufacturer of a broadcast receiving device or an electronic market (e.g., Google Play Store or App Store). For electronic distribution, at least a part of the software program may be stored in a storage medium or temporarily generated. In this case, the storage medium may be a server of a manufacturer, a server of an electronic market, or a storage medium of a relay server temporarily storing the software program. 
     The computer program product may include a storage medium of a server or a storage medium of a client device in a system that includes the server and the client device. Alternatively, when there is a third device (e.g., a smart phone) communicatively connected to the server or the client device, the computer program product may include a storage medium of the third device. Alternatively, the computer program product may include the software program transmitted from the server to the client device or the third device or transmitted from the third device to the client device. 
     In this case, one of the server, the client device, and the third device may execute the computer program product to perform the methods according to the embodiments of the disclosure set forth herein. Alternatively, two or more of the server, the client device, and the third device may execute the computer program product to distributively perform the methods according to the embodiments of the disclosure set forth herein. 
     For example, the server (e.g., a cloud server or an artificial intelligence server) may execute the computer program product stored therein to control the client device communicatively connected to the server to perform the methods according to the embodiments of the disclosure set forth herein. 
     In one embodiment of the disclosure, an electronic device may perform voice activity detection by applying different parameters according to a user&#39;s utterance characteristics, thereby improving the accuracy and efficiency of voice activity detection. 
     It is possible to prevent loss of utterance of a user having a low utterance rate and reduce an unnecessary waiting time of a user having a high utterance rate. 
     A user&#39;s utterance characteristics can be easily analyzed using utterance of a trigger word. 
     While embodiments of the disclosure have been described above in detail above, the scope of the disclosure is not limited thereto, and it should be understood that various modifications and improvements made by those of ordinary skill in the art using the basic concepts of the disclosure defined in the following claims are included within the scope of the disclosure.