Context-Aware Computing Overview and Case Studies

1. Context-Aware ComputingOverview and Case Studies Marko Jurmu MediaTeam Oulu Group University of Oulu Finland March 13th, 2007

2. Outline: • Fact Sheet: Finland • Motivation • Definitions of Context • Effects of Context-Awareness • Example Application Domains • CASE 1: Connectivity Management • CASE 2: RFID Symbolic Tags • CASE 3: Wearable Sensors • Raised Issues • References

3. Fact Sheet: Suomi (Finland) • Population: 5.3 mi • Area: 330.000 km2 (127.000 sq mi) • Independent since: Dec. 6, 1917 • Capital: Helsinki (ca. 1 mi) • Home of: • Santa Claus • NOKIA • Linus Torvalds • Jari Litmanen • Teemu Selänne • Jari Kurri

4. Motivation • Traditional computer systems execute blindly • Pre-defined application logic • Static user interfaces that require explicit attention • New kind of computing • Mobility is becoming a norm • Applications execute in less static environments • What can be done? • Enable computer systems to sense their surroundings • Encode changes in the surroundings to reflect to the application behavior

5. Motivation cont’d • But: • Coding explicit reflections into applications is laborous • Applications do not necessarily understand all changes • Applications may not be able to collect all the necessary information • We need: • Supporting platforms that facilitate application execution • Ways to gather disparate information and provide it in a unified way • Mechanisms to provide information without loss in semantics • These are the main research problems of context-aware computing

6. Definitions of Context • Schmidt et al. [1]: • Context is a series of transient hierarchical feature spaces • Very systematic definition

7. Definitions cont’d • Dey [2]: • ”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 the application themselves.” • Very loose definition, reflects well the common paradox in context-aware computing: • Applications can never be made aware of all possible context • In practice, the subset of context utilized by applications is strongly dictated by the sensing capabilities of underlying computer system

8. Definitions cont’d • Dey’s definition of context-awareness [2]: • ”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” • Important contrast: Previous discussion was strongly related to providing information that enables dynamic changes in the execution of the application • According to this definition, application is also context-aware if it can use context to filter the information presented to the user

9. Levels of Context • In their work [1], Schmidt et al. define 4 levels of context: • Raw sensor data • Readings acquired fromindividual sensors • Cues • Abstracted sensor data,possibly temporally aggregated • Context • Description of the current situationon an abstract level • Scripting • Allowing applications to benefitfrom context through simplescripts

10. Effects to Application Logic • Context-aware applications need to be designed differently from static applications: • Agile behavior on the face of rapid changes • Platform independence is required • Logic is distributed to better reflect the variance in the computing environments • The reflection to context changes can be encoded in several ways: • Definition of explicit rules and conditions • Increasing / decreasing application functionality • Dynamically maintaining the FSMs that controlthe application

11. Effects to Interaction • Traditional interaction: • Based on explicit user input • Static UIs with a certain conceptual models • User overwhelmed with unnecessary information • Situations worsens with ever-increasing information • Context-aware interaction: • Based on combination of implicit and explicit I/O • Implicit interaction does not require additional cognitive load • UIs that filter information and lessen the explicit controlling • More intuitive interaction models for users can be enabled

12. Example Application Domains • Location-aware applications: • Map-based guidance • Focused advertising • Weather / traffic services • Network-aware applications: • Video streaming • VoIP • File management operations • Combinations of these and other contexts: • Basically the list is endless, the following presents 3 enablers

13. CASE 1: Connectivity Management • Background: • Currently, wireless networking appearsthrough heterogeneous overlappingaccess networks • Mobility of the users is causing constantchanges to the configuration of activeradio interfaces • Connectivity can be based oninfrastructural or ad-hoc links • Networking applications in the mobile device need coherent mechanisms to cope with networking conditions

14. CASE 1 cont’d • Solution [3]: • Introduce a persistent networking interface for applications • Applications only see channels, and can specify different policiesfor network utilization

15. CASE 2: RFID Symbolic Tags • Background: • Invoking specific actions from mobile phone requires the navigation ofhierarchical menus • Can be very time-consuming, anddoes not guarantee that allaction-related parameters are entered correctly • All in all: Highly explicit UI

16. CASE 2 cont’d • Solution [4]: • Add RFID tags with intuitive symbols to the environment • Tag has action-related parameters encoded, so menu-based setting is not required • Still, users only see symbolic actions that can be invoked by touch

17. CASE 3: Wearable Sensors • Background: • Computer systems need information regarding the activities of the user to be able to support them • Having basic context like location is not necessarily enough • Activity is also correlated with artifacts being currently utilized

18. CASE 3 cont’d • Solution [5]: • Equip users with wearable sensors • Additional sensors in artifactsgive information on usage

19. Raised Issues • User control • Context-awareness takes control away from users • What is the right amount of user control? • User must feel that he/she is in control of the system • Two extremes: • Application asks everything from user (not very feasible) • (certainly not very feasible) • Privacy • Context-awareness requires the acquisition and storaging of information related to users and their surroundings • How to ensure correct management and avoid leakages? • How to avoid the collection of sensitive information?

20. Future Trends • From application point-of-view, mobility is turning multidimensional • Over administrative domain boundaries • Over device boundaries • Over social boundaries • Living environments are increasingly saturated with intelligent electronics • Available services increase • Digital and physical worlds increasingly overlap • Challenges lie ahead especially in dynamic session management between environments and mobile users

21. References [1] Schmidt, A., Beigl, M. & Gellersen, H.-W. (1999), There is more to context than location, Elsevier Computer and Graphics Journal 23(6): 893-901. [2] Dey, A. (2000), Towards better understanding of context and context-awareness, CHI 2000 Workshop on the What, Who, Where, When, Why and How of Context-Awareness. [3] Sun, J., Riekki, J., Jurmu, M. & Sauvola, J. (2005), Adaptive connectivity management middleware for heterogeneous wireless networks, IEEE Wireless Communications 12(6): 18-25. [4] Riekki, J., Salminen, T. & Alakärppä, I. (2006), Requesting pervasive services by touching RFID tags, IEEE Pervasive Computing 5(1): 40-46. [5] Pirttikangas, S., Fujinami, K. & Nakajima, T. (2006), Feature selection and Activity Recognition from Wearable Sensors, Proc. International Symposium on Ubiquitous Computing Systems (UCS2006), Seoul, Korea, Oct. 11-13, 2006, pp. 516-527.

22. Contact: marko.jurmu@ee.oulu.fi www.mediateam.oulu.fi www.oulu.fi http://en.wikipedia.org/wiki/Finland