1. Personal Activity Coordinator Shelley Zhuang Computer Science Division U.C. Berkeley Ericsson Workshop August 2000

2. PAC: What is it? Service coordination layer Collects contextual user information such as current geo-location, next destination from services such as GPS service, calendar service, IM-Anywhere (real-time presence, location, and behavior information) Spatial data (location, traffic, device type, etc) Temporal data (calendar data)

3. Goals Uncoupling of providers and consumers Extensibility High availability and fault tolerance Scalability Security Privacy

4. PAC Applications Real-time information about PAC users, enabling targeted message delivery and other enhanced services Assists the Preference Registry for more powerful service customization

5. Contextual Information Categorization Categorizing contextual information – information updating performance vs. finer grained access control) Hierarchical name space Sample hierarchical categorization tree root new appointmentstrafficlocationcalendar faxemailtrip timeGPSIP addressmailing addresslocationperson

6. Schema Definition XML namespace standard Referenced by a well-known URL Single schema definition file for each contextual information category Defines the properties of each field of a contextual information category Tags associated with each field are: Name, Description, Type, Enforcement, Values

7. Hierarchical Domain-based PAC Organization Separate PAC is provided for each individual user: ease of maintainability, privacy Individual PACs are organized in a hierarchical domain-based fashion Uniform contextual information presentation defined for each domain of PACs –Child domains inherit the presentations defined by their parents –Supports dynamic creation and deletion of a category, creation of additional fields for a category, and update of schema definition file URL at the domain level

8. Internal View of the PAC Hierarchical category namespace defined by the domain, and schema definition files Contextual information repository Subscriber Information –Service consumers subscribe to contextual information categories –Notified in response to the creation, deletion, update and expiration of contextual information

9. Architecture of PAC root Hierarchical Name Space name Server subscriber 5 subscriber 6 subscriber 7 subscriber server Subscribers Space subscriber 1 subscriber 2 subscriber 3 subscriber 4 subscriber server subscriber server Subscribers Space node server virtual node server node server virtual node server Contextual Information Repository Light-weight semi-structured distributed database

10. Security & Privacy Public key infrastructure For each contextual information category, the user can specify an Access Control List (ACL)

11. Garbage Collector Contextual information stored as soft state Allow the service providers to specify the lasting period of a contextual information

12. Execution Environment Runs on a Ninja base (iSpace  vSpace) Name Lookup Service (service-specific-id  user’s unique-id  personal information, i.e., preference registry, public key, PAC Xset database – XML based database and query model

13. Future Work Migrate to Ninja vSpace Implement the security model Support query-based notifications for finer grained control of the notification scheme Real-time changing data - GPS, IM-Anywhere User’s current activity – identify categorization and semantics