Context-Aware Computing: Integration with Rover

1. Context-Aware Computing:Integration with Rover Christian B. Almazan almazan@cs.umd.edu CMSC 818Z – Spring 2007 13 February 2007

2. What is Context? • An Attribute? • Location of an Event • Time of a Message • Temperature of the Room • Person of Interest • Provided as Part of Something Else? • Headers in an E-Mail Message • Surrounding Text in a Passage • How Does/Should Context Be Used?

3. Context as Defined by Academia • No Common Consensus [Dou01] • Etymology of Context [Win01] • “con” – with • “text” – meaning inferred from adjacent text • We take a look at a variety of definitions from several different fields/paradigms: • Pervasive/Ubiquitous Computing • Human-Computer Interaction • Service-Oriented Architectures

4. Context Defined by [CCDG05] • “Context is about...” • “...evolving” • “...structured” • “...shared information spaces...” • “...serve a particular purpose” • “Context...” • “...amplifies human activities with...” • “...new services that...” • “...adapt to circumstances they are used in”

5. Context Defined by [DA99] • “...is any information that can be used characterize the situation of an entity.” • “An entity is...” • “...a person, place, or object...” • “...considered relevant to interactions between a user and an application...” • “...including the user and applications themselves”

6. Context Defined by [ST94] • “...the location and identities of nearby people and objects and changes to those objects.” • Defines and records historical, provenance information • Based on location-aware computing • We’ll see this in Rover tracking and tagging

7. Context Defined by [Win01] • “Context...” • “is not just more text.” • “is effective only when it is shared.” • “emerges in dialog.” • “Context is an operational term.” • “...something is context because of the way it is used in interpretation...” • “...not due to its inherent properties.”

8. What is Context? (Revisited) • Is the definition of context different depending on the application scenario? • Does the definition of context include all of the definitions presented? • What, if any, notions of context are missing from this presentation? • Have we sufficiently captured all fields? • We mention context-awareness next.

9. What is Context-Aware? • Context-Awareness Approaches [Lok06] • Self-Supported • devices and hardware can perceive and reason with context without external support • Infrastructure Supported • devices and hardware utilize external sources to perceive and reason with context • What Can Be Context-Aware? • Entities (Devices, Humans, ...) • Services

10. What is Integration? • Let’s revisit the term ‘system’: • consists of many parts • parts communicate with each other • Integration, therefore... • combines the parts together • can be done... • directly: part-to-part • indirectly: middleware

11. What Can Be Integrated? • Any part of any system! • Kinds of systems: • Biological • Mathematical • Financial • Software • What kinds of integrated systems have you seen lately? • Think about how context can be used.

12. Student Information Systems • Components of the Information System • Transcript Records • Course Schedules • Human Resources • Bursar’s Office • Department-Specific Information • University Directories • Mostly WWW sites at UMCP. • How can context be used here?

13. First Responder Systems • Independent, but coordinated, entities: • 911 Call Center, EMT, Police, Firefighter • Homeland Security, CDC, FBI, CIA, NSA • How should each entity... • exchange information? • efficiency and privacy concerns • policy enforcement • utilize technology? • GPS, WiMAX, sensors, external data sources

14. Sample First Responder Scene

15. Integration Technologies • We have been creating new integration techniques since computing began. • Sampling of current technologies: • XML, XML Schema • Semantic Web: RDF, RDFS, OWL, OWL-S • Web Services: SOAP, REST, XML-RPC • Middleware Technologies: one.world, Gaia • Database Research: Rondo • This talk focuses on Rover [AYA07]

16. High Level Overview of Rover • Integration and Fusion Platform • (Designed to Be) Platform Independent • Context-Aware Services • (Primarily) Message-Based • Standardized Context-Aware Messaging • Client/Server or Peer-to-Peer Interaction • Every node utilizes the same software. • Can send and receive messages. • Install components at runtime.

17. Rover Visualized

18. Rover Architecture and Messages • Rover Nodes • All have (hopefully) unique identifiers (URIs) • Connection lookup on identifiers • Rover Messages • XML-based • Modeled after Semantic Web’s RDF • Triples: subject -> predicate -> object • Christian -> isPresenterOf -> SeminarTalk • subjects and predicates are URIs • objects are either URIs or literals

19. Base Rover Message • Guid • globally unique identifier • Activity • describes how to handle a message • one action, one or more sub-actions • Context (to be described...) • Content • triples, activity-specific information

20. Originator who generated? Concerning who is it about? Timestamp when created? Map what logical map? Area what places? Reader context obtained? Location where important? Radius does location reach? Context in Rover Messages

21. How is Context Supplied? • Automatically • Node identifier placed automatically • Location determination technologies (Horus) • Mapping identifiers placed accordingly • Manually • Anything the user deems appropriate • Try to make implicit context explicit!

22. Rover Messaging Handlers • Rover nodes can place handlers that can read, modify, and take action. • These handlers can be attached to: • all outgoing messages • all incoming messages • to a specific activity (action/sub-action) • Handlers can be for specialized for clients, servers, or both

23. Current Rover Implementation • Microsoft.NET 2.0 Framework • Asynchronous Networking Paradigm • XML-Based Messages • Client and Server Software the Same • Components can be specialized to be client, server, or both • Since XML messages are standardized, can develop Rover software for other platforms and programming languages

24. Implemented Components (1) • Dynamic Component Loading • from the local file system • over the network • Broadcast Chat • servers can send personal messages • Internet/WWW Services • Yahoo! RSS feeds for weather • Yahoo! API for news and web • caching performed on servers

25. Implemented Components (2) • Voice over IP • Microsoft’s RTP • voice and video • point and connect interface • Barcode Input • Enhanced Shopping Kiosk Experience • Tracking (details coming...) • Position • Tagging

26. Tracking • Server starts tracking server component • Can overlay an image • Client starts tracking client component • Can watch or participate • Upon starting the component, downloads current state of the tracking system • Overlay image • Positions • Tags • Updates periodically, or when requested

27. Tracking: Positions • Specify colors to indicate last time a position had been reported: • Normal [under 15s] – Blue • Warning [under 30s] – Orange • Problem [over 30s] – Red • Map can identify which areas have already been covered – Yellow

28. Tracking: Tags • Tagging Structure • Type of Tag – ‘Check It Out’ or ‘Warning’ • Placed or removed • Where you are • By an administrator/commander • Can leave additional textual information • ‘Check It Out’ Tags • Can assign the tag to one or all clients • Units can indicate they are reporting to tag • Blinks if no one responds within 10 seconds

29. UMCP Rover Demo Scenario

30. Scavenger Hunt Scenario • Multiplayer game based on tagging • Points scored based on when tags found • If more than two people play, the last person to find a tag could be generated an extra tag, but score more points if faster in that iteration, or something like that • Both physical and logical tags! • Physical: RFID, barcode, etc. • Logical: Radius logic tags, etc.

31. Potential Rover Enhancements • Currently single-server implementation • Would like multi-server/peer-to-peer • Additional location technologies • PinPoint • Better Integration Strategies • Utilize context better • Enhanced Tagging • More integrated applications!

32. Questions and Discussion • Need References Not on the Next Slide? • Ask Me for Them! • Can identifiers (e.g. URIs) have context? • How can context be used when integrating the following scenarios? • shopping mall (e.g. Arundel Mills) • emergency situation (e.g. bomb scare)

33. References • [AYA07] • Christian B. Almazan, Moustafa Youssef, and Ashok K. Agrawala. Rover: An Integration and Fusion Platform to Enhance Situational Awareness. The First International Workshop on Research Challenges in Next Generation Networks for First Responders and Critical Infrastructures. April 2007. To Appear. • [CCDG05] • Joëlle Coutaz, James L. Crowley, Simon Dobson, and David Garlan. Context is Key. Communications of the ACM. 48(3), pp 49-53. March 2005. • [DA99] • Anind K. Dey and Gregory D. Abowd. Towards a Better Understanding of Context and Context-Awareness. Proceedings of the 1st International Workshop on Managing Interactions in Smart Environments. 1999. • [Dou01] • Paul Dourish. Where the Action Is; The Foundation of Embodied Interaction. MIT Press, Cambridge, 2001. • [Lok06] • Seng W. Loke. Context-Aware Artifacts: Two Development Approaches. Pervasive Computing. 5(2), pp 48-53. April-June 2006. • [ST94] • Bill N. Schilit and Marvin M. Theimer. Disseminating Active Map Information to Mobile Hosts. IEEE Network. 8(5), pp 22-34. September-October 1994. • [Win01] • Terry Winograd. Architectures for Context. HCI Journal 2001.