A Survey of Context-Awareness

1. A Survey of Context-Awareness CS 570 Artificial Intelligence Term Project Team Edward : Hee-Jung Yang and Hyeong-Ho Yoo 2005. 12.19

2. Contents • Context & Context-Awareness • General Model of Context-Awareness • Sensing the Context • Sensing Context Changes • Context Modeling • Applications • Security & Privacy • Conclusion

3. Context and Context-Awareness • Context “Context is any information that can be used to characterize the situation of an entity. An entity is a person, place, or object that is considered relevant to the interaction between a user and an application, including the user and applications themselves.” [Dey and Abowd’s definition] • Context-Aware “A system is context-aware if it uses context to provide relevant information and/or services to the user, where relevancy depends on the user’s task.” [Dey’s definition]

4. General Model of Context-Awareness • Generation • Contextual information is obtained from UI or sensor • Processing • Change raw data to meaningful information • Usage • Use of contexts and possible reaction as output Generation Processing Usage

5. Sensing the Context • Sensing the Context • Raw contextual information • Location : location-tracking system (GPS) • Time : built-in clock of the computer • Light level : photodiode • Sound : microphone • High-level contextual information • User’s current activity : big challenge • Machine vision : camera technology, image processing • User’s calendar • Artificial Intelligence

6. Sensing Context Changes • Changes of Context • Most of contextual information changes as time goes on • Context changes can be sensed by • Periodic polling • Advertising • Selective polling

7. Context Modeling • Context Model • Define and store context data in a machine processable form • Context Modeling Approaches • Key-Value Models • Markup Scheme Models • Graphical Models • Object Oriented Models • Logic Based Models • Ontology Based Models

8. Context Modeling Approaches • Key-Value-Pairs Models • Most simple category of models • Not very efficient for more sophisticated structuring purposes • Only exact Matching • Markup Scheme Models • Scheme implements model • Typical representatives : profiles • Graphical Models • Particularly useful for structuring, but usually not used on instance level

9. Context Modeling Approaches • Object Oriented Models • Intention behind object orientation is (as always) encapsulation and reusability • Logic Based Models • Logic defines conditions on which a concluding expression or fact may be derived from a set of other expressions or facts (reasoning) → context is defined as facts, expressions and rules • High degree of formality

10. Context Modeling Approaches • Ontology Based Models • Ontology used as explicit specification of a shared conceptualization → strong in the field of normalization and formality • Context is modeled as concept and facts

11. Applications • Efficient UI • Reconfiguration • Triggering • Memory Retrieval • Sharing Experience

12. Security & Privacy • Protecting the gathered information • Each user have control over their contextual information • Not letting the system gather any information • User’s approval of information gathering

13. Conclusion • Context-Awareness will become a major trend in future • Ubiquitous computing • Adapting and tailoring services

14. References [1] B.Schilit and M.Theimer. Disseminating active map information to mobile hosts. IEEE Network, 8(5):22-32, 1994. [2] A.K. Dey and G.D. Abowd. Towards a better understanding of context and context-awareness. In Proceedings of the Workshop on the What, Who, Where, When and How of Context-Awareness, affiliated with the CHI 2000 Conference on Human Factors in Computer Systems, 2000. [3] A.K. Dey. Understanding and using context. Personal and Ubiquitous Computing, Vol. 5, 2001. [4] Strang, T. and Linnhoff-Popien, C. (2004). A context modeling survey. In First International Workshop on Advanced Context Modeling, Reasoning And Management, UbiComp 2004. [5] Bill N. Schilit, Norman Adams, and Roy Want, Context-aware computing applications. In IEEE Workshop on Mobile Computing Systems and Applications (Santa Cruz, CA, US, 1994) [6] W3C. Composite Capabilities / Preferences Profile (CC/PP). http://www.w3.org/Mobile/CCPP. [7] WAPFORUM. User Agent Profile (UAProf). http://www.wapforum.org. [8] Bauer, J. Identification and Modeling of Contexts for Different Information Scenarios in Air Traffic, Mar. 2003. Diplomarbeit. [9] Henricksen, K., Indulska, J., and Rakotonirainy, A. Generating Context Management Infrastructure from High-Level Context Models. In Industrial Track Proceedings of the 4th International Conference on Mobile Data Management (MDM2003) (Melbourne/Australia January 2003), pp.1-6. [10] Indulska, J., Robinsona, R., Rakotonirainy, A., and Henricksen, K. Experiences in using cc/pp in context-aware systems. In LNCS 2574: Proceedings of the 4th International Conference on Mobile Data Management (MDM2003) (Melbourne/Australia, January 2003), M.-S. Chen, P.K. Chrysanthis, M. Sloman, and A. Zaslavsky, Eds., Lecture Notes in Computer Science (LNCS), Springer, pp.247-261. [11] Schmidt, A., Beigl, M., and Gellersen, H.-W. There is more to context than location. Computers and Graphics 23, 6 (1999), 893-901. [12] Bacon, J., Bates, J., and Halls, D. Location-oriented multimedia. IEEE Personal Communications 4, 5 (1997). [13] Chen, H., Finin, T., and Joshi, A. Using OWL in a Pervasive Computing Broker. In Proceedings of Workshop on Ontologies in Open Agent Systems (AAMAS 2003) (2003). [14] Bill N. Schilit, Norman Adams, and Roy Want, Context-Aware Computing Applications [15] Peter Brown, Winslow Burleston, Mik Lamming, Odd-Wiking Rahlff, Guy Romano, Jean Scholtz, and Dava Snowdon, Context-awareness: some compelling appplications

15. Applications

16. Applications - Efficient UI • More efficient UI as context changes • Brighter display in dark place • Simplified text when I am moving normal dark place & user is moving

17. Applications - Efficient UI (cont’d) • Show only important part of clip for poor network bandwidth or small display • Different menu for different place • Sort people list by distance or show on a map • Depend on user’s preference big display small display

18. Applications - Reconfiguration • Optimize internal components • Choose the fastest connection to server • Use the memory of nearby idle computer rather than swapping to disk • Print with the closest printer • Reconfiguration overhead should be concerned

19. Applications - Triggering • Trigger useful info relevant to current context • Car navigation system • Explanation about the place where user travels • Show cooking guide in kitchen, show work files in office • Reminder for specified context • When I next meet X, tell him ... • When next at a grocery store, buy ...

20. Applications – Memory Retrieval • Save contexts of each event and retrieve them later • Who was the girl with Tom at the theatre yesterday? • What was the note I made at a meeting last July in this conference room? I remember Bill and John were there. • Object is defined by relative context • Filename is the context in which it is made • We don’t have to remember the filename • Interrupted task is resumed if the context revived

21. Applications – Sharing Experience • Refer other people's contexts • Travellers download my contexts of my trip here • Broadcast my context • I send to neighbours the info about cheap theatres here