1. Context Aware Toolkit 1 ©Jason Prideaux What is Context-Aware Computing?  Some definitions: Context: The physical and social situation in which the person/ device is a part of. Example Contexts: time of day, location, other people/devices, temperature, sound, light/vision, motion, network/internet, etc.  Goal of Context-Aware Computing: Acquire and utilize context from a computer device in order to provide services that are appropriate given the acquired context.

2. Context Aware Toolkit 2 ©Jason Prideaux What is Context-Aware Computing? (cont.)

3. Context Aware Toolkit 3 ©Jason Prideaux Navigator Application  We want to build a navigation aid that will give a person’s location and give directions to some destination.  Contexts that we need: Location  So, we need to build an app that will be able to read in context from a location sensor, such as a GPS device.

4. Context Aware Toolkit 4 ©Jason Prideaux Navigator Application (cont.)  We now want to add more context to our existing application, and share that context with other people.  Modifications: Add motion sensor Discover other devices Share context  Problems: Is the application extensible? If so, is it easy to add context? Should we re-architect the app? Should we start from scratch?

5. Context Aware Toolkit 5 ©Jason Prideaux Party Finder  Now we want to build an entirely new context-aware application. We want to find out if our friends are at a party.  Contexts: Sound Vision/light Motion Location Share context  Problems: How do we obtain such context? How do we go about sharing?

6. Context Aware Toolkit 6 ©Jason Prideaux Solution: Create a Middleware  Notice that there are needs that context-aware applications have in common: Access to sensors that provide context. Discovery of other people/devices around us. Ability to share context with other people/devices.  Solution: Create a middleware that will provide all of the above features. Advantages of a middleware: Maximum code reuse. Lightweight applications. A common language/description for context. Rapid development of context-aware applications.

7. Context Aware Toolkit 7 ©Jason Prideaux CAT: Context-Aware Toolkit  CAT is a middleware for context-aware applications. It provides: Easy access to all context from local sensors. Special Interest Groups (SIG) for sharing context. Applications can create virtual context. (soft sensors) History of all context can be saved. Prediction future context. Discovery other agents. Communication with other agents.

8. Context Aware Toolkit 8 ©Jason Prideaux CAT: Context-Aware Toolkit - Sensor Component  CAT creates a hierarchy of all sensors that exist on the device that it is running on.

9. Context Aware Toolkit 9 ©Jason Prideaux CAT: Context-Aware Toolkit  The Sensors in CAT then generate Context events, which applications can listen to. Available Context includes: Location, sound, light, and any other sensor data. Discovery of other agents. Incoming communication from other agents. Shared context from other agents. (remote sensing)  CAT applications also have access to several tools for: Creating SIGs. Joining SIGs. Sending messages/data to other agents. Accessing history/prediction of local and remote context.

10. Context Aware Toolkit 10 ©Jason Prideaux Conclusion  Retrieving context and sharing context is now simple and uniform for all context-aware applications.  Applications like Navigator and Party Finder can be rapidly developed with CAT, and developers need very little context- aware experience.  CAT itself is extensible, giving developers the ability to add new sensors and context types.

11. Context Aware Toolkit 11 ©Jason Prideaux References:  “Introduction to Context-Aware Computing” Thomas P. Moran, Paul Dourish. IBM Almaden Research Center, University of Califormia, Irvine. Special Issue of Human-Computer Interaction, Volume 16, 2001.  “CAT: Context-Aware Toolkit” Jason Prideaux, Stephen Fickas. Tentative Release: Spring 2004.  http://www.cs.uoregon.edu/research/wearables/CAT