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Agents on the Semantic Web

Agents on the Semantic Web. David De Roure Intelligence Agents Multimedia Dept of Electronics and Computer Science University of Southampton, UK dder@ecs.soton.ac.uk http://www.ecs.soton.ac.uk/~dder. Overview. The Pervasive Information Fabric Agents state of play Why agents need metadata

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Agents on the Semantic Web

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  1. Agents on theSemantic Web David De Roure Intelligence Agents Multimedia Dept of Electronics and Computer Science University of Southampton, UK dder@ecs.soton.ac.uk http://www.ecs.soton.ac.uk/~dder

  2. Overview • The Pervasive Information Fabric • Agents state of play • Why agents need metadata • Onward to ontologies

  3. Background This talk is based on the experience of building several applications (research prototypes) involving agents. These include: • Conceptual hypermedia and ontologies • Context-aware hypermedia linking • Information middleware for pervasive computing • Collaborative filtering systems • ‘Content based’ navigation of multimedia (images and music) We have also developed an Agent framework for Distributed Information Management

  4. Background Current activities include: • Mixed reality adaptive information systems • Advanced knowledge technologies • Disappearing computer initiative project • Simulation of very large scale distributed systems • Grid computing (information/knowledge grid)

  5. The Pervasive Information Fabric

  6. The Web of the past… • Is mainly a document dissemination Web • Can only link to multimedia • Assumes a traditional Web browser • Has static hyperstructure

  7. The Web of the future is… • Multimedia, including temporal media • Mobile (with different style of working) • Adaptive and open e.g. XLink • Collaborative • Automated (machine-to-machine e.g. XML) • Semantic (of course!) • And…

  8. …pervasive • Embedded internet • e.g. The Disappearing Computer Initiative • Large numbers of devices • Ad hoc networking (some support from IPv6) • Systems need to be self organising • Don’t wait for 1000s of bluetooth devices before exploring scalability issues! We call the middleware the Pervasive Information Fabric

  9. …virtual • Interface is 3D worlds, telepresence, VR • ‘click’ on object, query has spatial context • Visualisation of results? For example,abstract 3D midi visualisaton with links

  10. Scenario 1 – this meeting! • Our devices communicate using wireless/ad hoc networking, publishing information resources and associated metadata • A hyperstructure (web) is created on-the-fly, enabling us to navigate our local information space. Links derived from metadata, metadata derived from documents; also bookmarks. • When a message comes in (e.g. mobile phone call) it is routed appropriately to minimise invasiveness

  11. Scenario 2 – the musician • Musician walks on stage with bluetooth guitar • Musical devices on stage are located automatically, musician chooses to control appropriate instrument(s) • Plays a few notes, musical score appears on private display • More…the musician appears in virtual world, other musicians there too, playing virtual instruments, audible in physical world • (AR meets VR)

  12. Scenario 3 – the information grid • Group of experts deciding whether to make changes to production line in manufacturing organisation • Use multiple simulations to investigate • Processes farmed out across clusters (server farms) on WAN • Visualise results locally, collaboratively • Compare with results from previous runs • (Is this The Web?)

  13. AgentsState of Play

  14. Software agents • A buzzword for over 5 years now! • Classic early papers: • ‘Agents that reduce work and information overload’ 1994 • ‘Intelligent Agents: Theory and Practice’ 1995 • The paradigm of weak agency is widely accepted, especially in the Web area • There is a convenient subcategorisation into: • Personal and information agents • Multiagent systems

  15. Personal information assistants • Personal assistants that collaborate with the user at the user interface • Learning by ‘watching over their shoulders’, building and maintaining model of user • Believable agents (cf traditional media) • Movie/CD/book/document recommender agents exist, though with fairly weak user models • For ‘people’, read ‘businesses’

  16. Multiagent systems • Whole is greater than sum of the parts • Requires agent communication languages (eg KQML, FIPA ACL) • Ontology required – to agree the terms to be exchanged in communications • Agent frameworks have emerged • Few large scale systems exist

  17. Nwana’s appraisal “The ontology issues has always been considered secondary to other issues such as cooperation, negotiation, formalisation and logics for beliefs, desires and intentions, etc. ... This problem is at the core of the agent interoperability issue – is it reasonable to expect knowledge and cooperation level interoperability without a significant degree of ontological sophistication of the agents concerned?” Nwana and Ndumu, A Perspective on Software Agents Research, BT Labs

  18. My appraisal • XML, RDF(S) are useful infrastructure • Need also to address… • Scalability – putting the ‘multi’ into multiagent! • Security – not just an add-on • Performance • Real systems!

  19. Current work • Collaboration and negotiation between agents • Market-based models, e.g. auctions • See http://www.ecs.soton.ac.uk/~nrj • Applications in e-commerce but also telecoms • Agents in the PIF; e.g. briefing room scenario – routing information in right format to right device at right time, taking account of security and invasiveness issues

  20. Agents and metadata

  21. Agents… • Use metadata to find resources and work with them • They also create and maintain metadata • For example, our ‘query by humming’ system • MIDI data gathered from net • Tidied • Channels classified and indexed • Queries routed by index servers • Results presented (e.g. SMIL) • There is also metadata associated with the agents!

  22. Agents…recommender systems • MEMOIR, an early agent-based recommender system • Logged trails in object-oriented database • Users could ask ‘who else has looked at these documents?’ and ‘what else did they look at?’ • Later used keywords from docs in trails (and bookmarks) to model users • Can now search and present results with a notion of context • Through COHSE, will be able to navigate concept space

  23. Open Hypermedia Separable hyperstructure Link database Note the direction of this arrow! documents

  24. Hyperstructure as metadata • Open hypermedia introduces separable hyperstructure, e.g. as supported through XLink • Southampton model introduces reuseable separable hyperstructure, which can be applied to new documents • Agents used for link resolution • Agents build link databases and maintain them

  25. A case for streaming metadata? • Three kinds of multimedia streams: • Media on demand • Live, one way • Two way • Live metadata may be created by: • Producer (e.g Big Brother) • Video segmentation and classification • Annotation • There are multiple simultaneous flows of data, from multiple sources • Metadata needs to come from upstream in production process!

  26. Onward to ontologies

  27. Agents using the Semantic Web • Scenarios revisited: • Workshop scenario. Use ontology for our domain of interest. (And for IST?) Multimedia ontology for delivery of multimedia content. • Musician. Use ontology for navigating the musical information space. What about information about musical devices? Creation of metadata for new compositions. • Information grid. Ontologies for manufacturing and organisation. What about computational resources? • Also need to find agents, and to communicate with them • Hence working with multiple, distributed, ontologies.

  28. SoFAR • SoFAR (the Southampton Framework for Agent Research) is a versatile multi-agent framework designed for Distributed Information Management tasks. • SoFAR embraces the notion of proactivity as the opportunistic reuse of the services provided by other agents, and provides the means to enable agents to locate suitable service providers. • SoFAR combines some ideas from the distributed computing community with the performative-based communications used in many agent systems: communications in SoFAR are based on the startpoint/endpoint paradigm, which is the foundation of Nexus, the communication layer at the heart of the Computational Grid.

  29. Index of /distrib/sofar024/ontology NameLast modifiedSizeDescription Parent Directory 16-Nov-2000 22:45 - actions/ 16-Nov-2000 22:45 - base/ 16-Nov-2000 22:45 - fohm/ 16-Nov-2000 22:45 - infrastructure/ 16-Nov-2000 22:46 - metadata/ 16-Nov-2000 22:45 - multimedia/ 16-Nov-2000 22:46 - system/ 16-Nov-2000 22:45 - web/ 16-Nov-2000 22:45 – Apache/1.3.9 Server at www.sofar.ecs.soton.ac.uk Port 80

  30. HyStream example • Agents deal with multimedia streams • ACL handles session control, synchronisation, linking • Publish-subscribe • Example predicates: • ContainsContour(music, contour, time) • Relay(multicast_address1, multicast_address2) • The mediadata-metadata distinction becomes blurred, e.g. when features extracted from multimedia documents

  31. Agents supporting the Semantic Web • Metadata, vocabularies, thesauri, ontologies are ‘stuff’ in the information space • Note distinction between: • Automation of tasks, i.e. computer-to-computer interaction (a goal of XML et al) • Ontology capture and design tools involving humans • Agents help with both; it’s the first that really helps agents (and is supported by current web technologies)

  32. The (distributed) intelligence • Currently agents ‘wrap’ existing inference engines • Agent Based Computing is an appropriate paradigm to work in complex world with multiple ontologies, fragments, multiple inferencing engines • We anticipate further decomposition into multiple inferencing components

  33. Future work at Southampton • Ontology support for agent collaboration and negotiation • Ontologies and hypermedia (COHSE, Pervasive) • Use of OIL/DAML • Instantiating application-neutral ontologies for agent infrastructure • Agents supporting the knowledge lifecycle

  34. Summary

  35. Summary • The fabric of the Web is changing • DIM agents eat metadata for breakfast • XML and RDF(S) support agent-agent interaction • Agents not only use but also automate the construction and maintenance of metadata and ontologies dder@ecs.soton.ac.uk

  36. Motivation “There will always be plenty of things to compute in the detailed affairs of millions of people doing complicated things” “Consider a future device for individual use, which is a sort of mechanized private file and library. It needs a name, and to coin one at random, “memex” will do. A memex is a device in which an individual stores all his books, records, and communications, and which is mechanized so that it may be consulted with exceeding speed and flexibility. It is an enlarged intimate supplement to his memory” – Bush, July 1945

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