1. Context Workshop

2. Diepenbeek 22 january 2004 Agenda Introduction Work methodology Context description Description frameworks Conclusion Questions

3. Diepenbeek 22 january 2004 Introduction Context = con – text  Comes from literature General meaning  Facts or circumstances surrounding situation or event In computer science  No consensus  Case based  Poses new challenges

4. Diepenbeek 22 january 2004 Work methodology Workgroup Understanding of context in literature Decisions about context based on  Literature  Understanding of own needs  Discussion with partners Preliminary validation  Scenarios with use cases and behaviour  Sample specifications  Workshop

5. Diepenbeek 22 january 2004 Context description Ontology  Provides meta-data  Relations within terminology  Easier to reason Use  Exchange of context information  Easier for versioning Work in progress  Further integration of established naming conventions (based on e.g. UAPROF)  Further refinement needed  Suggestions welcome

6. Diepenbeek 22 january 2004 Context description Relations with external entities Four parts  Services  Platform  User  Environment

7. Diepenbeek 22 january 2004 Services - Overview General definition: “A single autonomous process or composition of interacting processes that benefits the user.” Relevance to context:  Specify available services Self-hosted (local) In the neighbourhood (remote)  Specify relationships with other entities The user and platform Interaction with other services  Goal: Use context to take smart decisions on behalf of the user

8. Diepenbeek 22 january 2004 Services - Overview Other service properties:  Service execution: Download to local device or execute remotely All processes on the same device or distributed over a network of devices Parallel or serial execution (or a combination)  Service platform Service migration Service platform heterogeneity  Services adapting to context changes

9. Diepenbeek 22 january 2004 Services - Overview

10. Diepenbeek 22 january 2004 Services - Overview Service description:  Coarse-grained specification High-level information to decide if we are interested in the service Semantic service discovery E.g.: “I need a messaging service.”  Fine-grained specification Provided and required service interfaces Service composition E.g.: APIs, non-functional requirements, …  Service ontology that maps on context ontology: DAML-S and OWL-S Standard specification Provides multi-level service specification

11. Diepenbeek 22 january 2004 Services - Overview OWL-S ontology comprises three parts:  Service Profile: Properties for automatic discovery Service functionality Inputs / Outputs Preconditions / Effects Cfr.: Yellow page entry  Service Model Control flow and data flow involved in using the service Composition and execution of services  Service Grounding: Mapping to WSDL and SOAP Communication-level protocols Message descriptions

12. Diepenbeek 22 january 2004 Services - Overview OWL-S:

13. Diepenbeek 22 january 2004 Platform – Overview specification platform softwarehardwareruntime operating system virtual machine library driver rendering engine input device output device resource cpu network power environment wireless service user interface code generation Concrete UIpart Modality has Is a has Is a Can Present has Influenced by has Renders Is a wired storage persistentvolatile Is a supports

14. Diepenbeek 22 january 2004 Platform – Run-time/Software Run-time environment  Operating system (API, libc) Name, edition, version  Virtual machine(s) API (J2SE 1.4.1,...) Name & edition (SUN JRE 1.4.1, JikesRVM 2.3.2) Software  Name, version  Rendering engine modality

15. Diepenbeek 22 january 2004 Platform – Hardware CPU  Cache: sizes & organisation (levels + mapping scheme)  Branch prediction: type, table sizes, RAS, BTB, update strategy,...  TLB: sizes & organisation (levels)  Execution units  Instruction window  Fetchbuffer size ...

16. Diepenbeek 22 january 2004 I/O  Screen (size, colordepth, touch?,...)  Data-entry (keypad,...)  Network (ethernet, bluetooth, IR,...) Storage (volatile & persistent): size & available Power: total & available Platform – Hardware

17. Diepenbeek 22 january 2004 Platform – Hardware Lot of options Not everything available for every CPU Extensible subset

18. Diepenbeek 22 january 2004 User - Overview preference profile user role task activity Consists of has service Uses

19. Diepenbeek 22 january 2004 User - Overview User  Preferences: only relevant for device?  Role: only current role?  Profile: contains properties of the user Properties can be complex (agenda) or simple (name)  Tasks: what the user wants to do Contains: activities (concrete actions)

20. Diepenbeek 22 january 2004 Environment - Overview platform environment location environmental condition temperature pressure humidity lighting noise addressposition absoluterelativesensor Sensed by Is a has

21. Diepenbeek 22 january 2004 Environment - Overview Physical environment  Sensed information  Environmental Condition: properties Sensed by/ produced by  Sensor  Service: combined information? Accuracy Scale Time stamp

22. Diepenbeek 22 january 2004 Environment - Overview  Location Most used environment attribute Special treatment?

23. Diepenbeek 22 january 2004 Description Frameworks RDF/S (XML)  Description of resource  Limited in relations  lot of freedom CC/PP, UAPROF  CC/PP Description of profiles/capabilities Components with properties Properties can be components  UAPROF: WAP description of platform/user agent

24. Diepenbeek 22 january 2004 Description Frameworks OWL  Ontology language Many possibilities for relations  Already used for context Aspect-Scale-Context information (ASC model)

25. Diepenbeek 22 january 2004 Conclusion Description of context  Ontology  Express in OWL (ongoing work) Half way first time frame  Preliminary results  Feedback

26. Diepenbeek 22 january 2004 Questions Platform/device centric  Good starting point?  Should other things be taken into account? Right focus?  Elements with too much/little detail? Description language?  Which, Wherefor? Too much/little in context:  Leave certain things out? Bring things in?