Multi-Agent Systems for Information Retrieval on the World Wide Web Buchkatalog

Inhaltsangabe:Abstract: This Diploma thesis describes the implementation of a prototype multi-agent system. The system consists of four different types of agents and is based on the Java Agent Template, an agent framework freely available from Stanford University. The purpose of the multi-agent system is to aid users in searching and retrieving information available on the WorldWideWeb. Information is categorized in concepts and the different agent share and exchange the knowledge about concepts and documents on the WWW that matches these concepts. This thesis presents how the information is modeled and how it is communicated between the agents of the system. It also includes prototypes of the agents that demonstrate a working implementation of the approach. Inhaltsverzeichnis:Table of Contents: 1.Introduction8 2.Information Retrieval on the WorldWideWeb10 2.1The structure of information11 2.2The meaning of information12 2.3Locating information13 2.4The nature of a search query15 2.5Information gathering and query16 2.6Conclusion17 3.The agent paradigm18 3.1An agent from the userÕs point of view19 3.2Agent properties20 3.2.1Environment20 3.2.2Intelligence21 3.2.3Learning22 3.2.4Autonomy22 3.2.5Communication22 3.2.6Multi-agent systems23 3.2.7Mobility24 3.3Conclusion24 4.The CEMAS information model25 4.1Definition of user and search25 4.2The concept architecture26 4.2.1Definition of a link26 4.2.2Definition of a concept27 4.2.3The concept tree30 5.The CEMAS agent architecture33 5.1The Knowledge Query and Manipulation Language34 5.2The Java Agent Template (JAT)37 5.2.1JAT knowledge37 5.2.2JAT communication38 5.3CEMAS agents41 5.3.1CEMAS knowledge42 5.3.2CEMAS communication43 5.3.3The ConceptBroker agent46 5.3.4The ConceptServer agent48 5.3.5The ConceptClient agent49 5.3.6The ConceptSearch agent51 6.Example53 6.1Example concept tree53 6.2Example session54 6.2.1Example ConceptClient session55 6.2.2Example ConceptSearch Session60 7.Implementation64 7.1JAT agent overview64 7.2JAT messaging67 7.3Package agent69 7.4Package context72 7.5Package resource73 7.5.1Resource types75 7.5.2ConceptFile class78 7.6ConceptUtil package79 8.Discussion80 8.1The agent paradigm80 8.2The concept model81 8.3Implementation83 8.3.1Communication83 8.3.2ConceptBroker83 8.3.3ConceptServer83 8.3.4ConceptClient84 8.3.5ConceptSearch85 8.4Conclusion86 9.Bibliography87 Appendix A90 Appendix B91 Appendix [...]