An apparatus for determining a user's mental state in a terminal is provided. The apparatus includes a data collector configured to collect sensor data; a data processor configured to extract feature data from the sensor data; and a mental state determiner configured to provide the feature data to an inference model to determine the user's mental state.
Please help me write a proper abstract based on the patent claims. CLAIM: 1. A terminal system, comprising: one or more processors configured to: collect sensor data generated as a user is using a terminal configured for composing a message; determine a pictorial representation for the user, based on extracted feature data from the sensor data, the extracted feature data reflecting an observed emotion of the user; and control an implementation of one or more predetermined measures based on the determined pictorial representation for the user. 2. The system of claim 1, wherein at least one of the one or more processors is further configured to provide an emoticon corresponding to the determined pictorial representation for the user. 3. The system of claim 2, wherein the determining of the pictorial representation for the user is based on user confirmation of the provided emoticon for the emotion of the user, a feeling, and/or stress of the user when the user is composing the message. 4. The system of claim 2, wherein for providing the pictorial representation to the user, the at least one of the one or more processors is configured to use an algorithm in the determining of the pictorial representation for the user. 5. The system of claim 1, wherein the extracted feature data includes text input information. 6. The system of claim 1, wherein the one or more processors are further configured to: determine a mental state of the user based on the extracted feature data from the sensor data reflecting the observed emotion of the user; determine the pictorial representation for the user, updated based on the extracted feature data from the sensor data and the determined mental state of the user; and provide the updated pictorial representation to the user. 7. The system of claim 6, wherein the extracted feature data includes text input information, and the text input information includes one or more of keyboard input information, writing input information, and terminal state information. 8. The system of claim 6, wherein the one or more predetermined measures comprise recommending content based on the mental state of the user. 9. The system of claim 8, wherein the recommending of the content based on the mental state of the user includes recommending the content to the user based on the mental state of the user. 10. The system of claim 6, wherein the extracted feature data includes text input information, and the text input information includes one or more of keyboard input information, writing input information, and terminal state information, and wherein the sensor data are measured through one or more of a keyboard, a stylus pen, a touch screen, an accelerometer sensor, a gyroscope sensor, a magnetometer sensor, an orientation sensor, a global positioning system (GPS), a barometer sensor, a fingerprint sensor, an illuminance sensor, a microphone, and a software sensor of the terminal. 11. The system of claim 10, wherein the feature data further comprises context information; and the context information comprises one or more of a location, weather, a discomfort index, a time, an average illuminance, and one or more words of the composed message. 12. The system of claim 10, wherein the keyboard input information includes at least one of a typing speed, a length of the longest text, a length of the shortest and longest deleted text, a number of words typed per editing, a number of long touches per editing, a frequency of use of backspace key, a frequency of use of enter key, and a frequency of use of special sign, the writing input information includes at least one of a writing input speed, a writing pressure, a character size, a straightness or curvature of a character stroke, a character interval, a row interval, and writing input regularity, and the terminal state information includes at least one of a number of shakings of the terminal, a degree of inclination of the terminal, a remaining capacity of a battery, and a voice volume. 13. The system of claim 6, wherein the one or more predetermined measures comprise providing information on the determined mental state of the user, controlling a user interface based on the determined mental state, and/or recommending content based on the determined mental state of the user. 14. The system of claim 6, wherein the one or more predetermined measures comprise controlling a user interface of the terminal based on the determined mental state, at least one of the one or more processors being configured to provide the user interface within at least one of a text or messaging application, an email application, a social network service (SNS) application, a multimedia application, a gaming application, an internet browsing application, a shopping application, and a navigation application. 15. The system of claim 14, wherein, to implement the controlling of the user interface of the terminal, the at least one of the one or more processors is configured to change at least one of themes of the user interface depending on the determined mental state, the at least one of the themes including a font, a font size, a color, a background, a brightness and corresponding to items of the text input information for the user interface. 16. The system of claim 14, wherein, to implement the controlling of the user interface of the terminal, the at least one of the one or more processors is configured to change at least one of a font, a font size, a color, a background, a brightness and items corresponding to the text input information for the composed message depending on the determined mental state. 17. The system of claim 1, wherein at least one of the one or more processors is configured to provide the determined pictorial representation to the user, wherein the data collector is further configured to connect to a camera or image sensor of the terminal to collect the sensor data therefrom, and wherein the determined pictorial representation corresponds to a facial expression for the user. 18. The system of claim 1, wherein the controlling of the implementation includes providing the pictorial representation for the user as feedback to the user of information of a determination of the emotion of the user. 19. A processor-implemented method of determining a pictorial representation of a user, the method comprising: collecting sensor data generated as the user is using a terminal configured for composing a message; determining the pictorial representation for the user, based on extracted feature data from the sensor data, the extracted feature data reflecting an observed emotion of the user; and controlling an implementation of one or more predetermined measures based on the determined pictorial representation for the user. 20. The method of claim 19, further comprising providing an emoticon corresponding to the determined pictorial representation for the user. 21. The method of claim 20, wherein the determining of the pictorial representation for the user is based on user confirmation of the provided emoticon for the emotion of the user, a feeling, and/or stress of the user when the user is composing the message. 22. The method of claim 20, wherein the determining of the pictorial representation for the user and controlling of the implementation of the one or more predetermined measures based on the determined pictorial representation for the user, including the providing of the pictorial representation to the user, includes using an algorithm in the determining of the pictorial representation for the user. 23. The method of claim 19, wherein the extracted feature data includes text input information. 24. The method of claim 19, further comprising: determining a mental state of the user based on the extracted feature data from the sensor data reflecting the observed emotion of the user; determining the pictorial representation for the user, updated based on the extracted feature data from the sensor data and the determined mental state of the user; and providing the updated pictorial representation to the user. 25. The method of claim 24, wherein the extracted feature data includes text input information, and the text input information includes one or more of keyboard input information, writing input information, and terminal state information. 26. The method of claim 24, wherein the one or more predetermined measures comprise recommending content based on the mental state of the user. 27. The method of claim 26, wherein the recommending of the content based on the mental state of the user includes recommending the content to the user based on the mental state of the user. 28. The method of claim 24, wherein the extracted feature data includes text input information, and the text input information includes one or more of keyboard input information, writing input information, and terminal state information, and wherein the sensor data are measured through one or more of a keyboard, a stylus pen, a touch screen, an accelerometer sensor, a gyroscope sensor, a magnetometer sensor, an orientation sensor, a global positioning system (GPS), a barometer sensor, a fingerprint sensor, an illuminance sensor, a microphone, and a software sensor of the terminal. 29. The method of claim 28, wherein the feature data further comprises context information; and the context information comprises one or more of a location, weather, a discomfort index, a time, an average illuminance, and one or more words of the composed message. 30. The method of claim 28, wherein the keyboard input information includes at least one of a typing speed, a length of the longest text, a length of the shortest and longest deleted text, a number of words typed per editing, a number of long touches per editing, a frequency of use of backspace key, a frequency of use of enter key, and a frequency of use of special sign, the writing input information includes at least one of a writing input speed, a writing pressure, a character size, a straightness or curvature of a character stroke, a character interval, a row interval, and writing input regularity, and the terminal state information includes at least one of a number of shakings of the terminal, a degree of inclination of the terminal, a remaining capacity of a battery, and a voice volume. 31. The method of claim 24, wherein the one or more predetermined measures comprise providing information on the determined mental state of the user, controlling a user interface based on the determined mental state, and/or recommending content based on the determined mental state of the user. 32. The method of claim 24, wherein the one or more predetermined measures comprise controlling a user interface of the terminal based on the determined mental state, including providing the user interface within at least one of a text or messaging application, an email application, a social network service (SNS) application, a multimedia application, a gaming application, an internet browsing application, a shopping application, and a navigation application. 33. The method of claim 32, wherein, the controlling of the user interface of the terminal further comprises changing at least one of themes of the user interface depending on the determined mental state, the at least one of the themes including a font, a font size, a color, a background, a brightness and corresponding to items of the text input information for the user interface. 34. The method of claim 32, wherein the controlling of the user interface of the terminal further comprises changing at least one of a font, a font size, a color, a background, a brightness and items corresponding to the text input information for the composed message depending on the determined mental state. 35. The method of claim 19, further comprising providing the determined pictorial representation to the user, wherein the data collector is further configured to connect to a camera or image sensor of the terminal to collect the sensor data therefrom, and wherein the determined pictorial representation corresponds to a facial expression for the user. 36. The method of claim 19, wherein the controlling of the implementation includes providing the pictorial representation for the user as feedback to the user of information of a determination of the emotion of the user.