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An Inference Engine for RDF

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An Inference Engine for RDF An inference engine for RDF An inference engine for RDF Master thesis G. Naudts 30 october 2003 Open University of the Netherlands Agfa Gevaert 1 An inference engine for RDF 2 An inference engine for RDF This document is the Master Thesis made as a part of my Master Degree in Computer Science Education (Software Systems) at the Open University of the Netherlands. The work has been done in collaboration with the research department of the company Agfa in Mortsel Belgium. Student data Name Guido Naudts Student number 831708907 Address Secretarisdreef 5 2288 Bouwel Telephone work 0030-2-542.76.01 Home 0030-14-51.32.43 E-mail [email protected] Coaching and graduation committee Chairman: dr J.T. Jeuring, professor at the Open University Secretary : ir. F.J. Wester, senior lecturer at the Open University Coach: ir. J. De Roo, researcher at Agfa Gevaert. 3 An inference engine for RDF Acknowledgements I want to thank Ir. J. De Roo for giving me the opportunity for making a thesis about a tremendous subject and his guidance in the matter. Prof. J. T. Jeuring and Ir. F. J. Wester are thanked for their efforts to help me produce a readable and valuable text. I thank M. P. Jones for his Prolog demo in the Hugs distribution that has been very helpful. I thank all the people from the OU for their efforts during the years without which this work would not have been possible. I thank my wife and children for supporting a father seated behind his computer during many years. 4 An inference engine for RDF An inference engine for RDF ...................................................................1 Summary ..................................................................................................................................11 Samenvatting............................................................................................................................13 Chapter 1. Introduction...........................................................................................................15 1.1. Overview .......................................................................................................................................... 15 1.2. Case study............................................................................................................................................. 15 1.2.1. Introduction ......................................................................................................................................... 15 1.2.2. The case study ..................................................................................................................................... 15 1.2.3. Conclusions of the case study.............................................................................................................. 17 1.3. Research goals...................................................................................................................................... 17 1.3.1. Standards............................................................................................................................................. 17 1.3.2. Research questions .............................................................................................................................. 18 1.4. Research methods ................................................................................................................................ 19 1.5. The basic material................................................................................................................................ 20 1.6. Related work ........................................................................................................................................ 20 1.7. Outline of the thesis ............................................................................................................................. 21 Chapter 2. Preliminaries .........................................................................................................22 2.1. Introduction.......................................................................................................................................... 22 2.2. XML and namespaces ......................................................................................................................... 22 2.2.1. Definition ............................................................................................................................................ 22 2.2.2. Features ............................................................................................................................................... 22 2.3. URI’s and URL’s ................................................................................................................................. 24 2.3.1. Definitions........................................................................................................................................... 24 2.3.2. Features ............................................................................................................................................... 24 2.4. Resource Description Framework RDF............................................................................................. 25 2.4.1. Introduction ......................................................................................................................................... 25 2.4.2. Verifiability of a triple......................................................................................................................... 26 2.4.3. The graph syntax ................................................................................................................................. 26 2.4.4. Conclusion........................................................................................................................................... 27 2.5. Notation 3 ............................................................................................................................................. 27 2.5.1. Introduction ......................................................................................................................................... 27 2.5.2. Basic properties................................................................................................................................... 27 2.6. The logic layer...................................................................................................................................... 28 2.7. Semantics of N3.................................................................................................................................... 29 2.7.1. Introduction ......................................................................................................................................... 29 2.7.2. The model theory of RDF ................................................................................................................... 29 2.7.3. Examples ............................................................................................................................................. 30 2.8. RDFProlog............................................................................................................................................ 30 2.8.1. Introduction ......................................................................................................................................... 30 2.8.2. Syntax.................................................................................................................................................. 31 2.9. A global view of the Semantic Web .................................................................................................... 31 2.9.1. Introduction. ........................................................................................................................................ 31 2.9.2. The layers of the Semantic Web.......................................................................................................... 31 3. Related work.........................................................................................................................34 3.1. Automated reasoning........................................................................................................................... 34 5 An inference engine for RDF 3.1.1. Introduction ......................................................................................................................................... 34 3.1.2. General remarks .................................................................................................................................. 34 3.1.3. Reasoning using resolution techniques................................................................................................ 35 3.1.4. Backward and forward reasoning........................................................................................................ 37 3.1.5. Other mechanisms ............................................................................................................................... 38 3.1.6. Theorem provers ................................................................................................................................. 38 3.1.7. Conclusion........................................................................................................................................... 39 3.2. Logic.....................................................................................................................................................
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