Semantic Web

Lecture

Abstract

The Semantic Web is envisioned as the next generation of the Web which allows for automatic retrieval and combination of information on a world-wide scale. In this lecture you will learn about the architecture, the representation mechanisms and languages (RDF, RDFs, OWL, RIF) and the emerging Linked Open Data. Furthermore, you will learn about innovative Web-scale reasoning techniques, about Ontologies which are the backbone of the Semantic Web as well as about tools and applications of Semantic Web technologies.

1 Introduction. This lecture provides an introduction to the subject of Semantic Web: the basics and the history of the Web, its limitations, and the vision of the Semantic Web and its core examples.

2 Semantic Web Architecture. This lecture introduces a Semantic Web architecture and its components, namely Uniform Resource Identifier, Extensible Markup Language, XML Schema, Namespaces. Data management examples explain how the architecture foundations are used.

3 Resource Description Framework (RDF). This lecture explains in detail the RDF layer of the Semantic Web stack, in particular, the foundations, such as RDF, RDF Schema, RDF(S) Semantics, RDF(S) Serialization, and implementation aspects such as serialization, entailment. An overview of common RDF tools and ontologies are given as examples.

4 Web of Data. This lecture explains the Web of Data: its origin, evolution and principles. Technologies enabling publication of structured data on the Web are described: Microformats, RDFa, GRDDL. Additionally, Linked Data publishing and consumption principles are explained.

5 Semantic Annotation. This lecture presents methods of semantic annotation generation. The main natural language processing ideas are outlined. In particular, the semi-automatic annotation of text is addressed (system KIM, GATE as examples), and the annotation of multimedia.

6 Storage and Querying. This lecture explains how to store and query RDF data. An overview of the state-of-the-art RDF repositories (Sesame, OWLIM, etc.) and their APIs, as well as SPARQL language introduction are comprised.

7 Web Ontology Language (OWL). The lecture presents and motivates Web Ontology Language (OWL), detailing it basics and dialects: OWL-Lite, OWL-DL, OWL Full. As examples, it provides an overview of tools supporting OWL.

8 Rule Interchange Format (RIF). The lecture presents and motivates Rule Interchange Format (RIF), detailing its syntax and semantics. Connections to different types of logics (first order, horn, description) are explained.

9 Reasoning on the Web. This lecture explains reasoning, in particular the reasoning types applicable to the Web. It introduces Approximate Reasoning, Bounded Reasoning, and gives illustrations from projects LarKC and MaRVIN.

10 Ontologies. This lecture introduces ontologies, in particular, their application to the Semantic Web. It also defines ontology engineering and explains several ontology engineering methodologies.

11 Social Semantic Web. The lecture illustrates the shift from Web to Web 2.0, and provides a number of examples of Web 2.0 applications. Basing on these, further Web evolution, i.e. Social Semantic Web is introduced.

12 Semantic Web Services. This lecture introduces the concept of a service, in particular, in application to the Web, web service technologies (WSDL, SOAP, UDDI). Then it motivates and defines Semantic Web Services, and exemplifies their implementation, in particular by WSMO, WSML, WSMX technologies.

13 Tools. This lecture introduces and gives examples for different types of semantic technology tools. Specifically, semantic crawlers, ontology editors, annotation tools, and storage and reasoning tools are covered.

14 Applications. This lecture overviews validation of Semantic Web technologies in real life case studies. In particular, Dr. Watson, Yahoo! SearchMonkey, ACTIVE case study, INSEMTIVES case studies, and LARKC case study are explained.

Slides

Wikipedia

• http://en.wikipedia.org/wiki/Semantic_Web
• http://en.wikipedia.org/wiki/Semantic_Web_Stack
• http://en.wikipedia.org/wiki/Resource_Description_Framework
• http://en.wikipedia.org/wiki/RDF_Schema
• http://en.wikipedia.org/wiki/Web_Ontology_Language
• http://en.wikipedia.org/wiki/SPARQL
• http://en.wikipedia.org/wiki/Rule_Interchange_Format
• http://en.wikipedia.org/wiki/Microformats
• http://en.wikipedia.org/wiki/RDFa
• http://en.wikipedia.org/wiki/Linked_Data
• http://en.wikipedia.org/wiki/SPARQL
• http://en.wikipedia.org/wiki/Rule_Interchange_Format
• http://en.wikipedia.org/wiki/Horn_logic
• http://en.wikipedia.org/wiki/Datalog

Links

• http://www.w3.org/TR/rdf-primer/
• http://www.w3.org/TR/rdf-mt/
• http://linkeddata.org/
• http://www.w3.org/TR/rdf-sparql-query/
• http://www.w3.org/TR/owl-features/
• http://www.w3.org/2005/rules/wiki/RIF_Working_Group
• http://microformats.org/
• http://gate.ac.uk/overview.html
• http://www.ontotext.com/kim/
• http://www.openrdf.org/
• http://www.ontotext.com/owlim/

Further reading

• T. Heath and C. Bizer. Linked Data: Evolving the Web into a Global Data Space, (1st edition), Morgan & Claypool, 2011.
• D. Fensel, E. Simperl and I.Toma. Semantic Web Handbook, Springer, to appear in 2011.
• D. Fensel, J. Domingue, J.A. Hendler (editors). Handbook of Semantic Web Technologies, Springer, 2010 (to appear).
• D. Fensel. Ontologies: A Silver Bullet for Knowledge Management and Electronic Commerce, 2nd Edition, Springer 2003.
• G. Antoniou and F. van Harmelen. A Semantic Web Primer, (2nd edition), The MIT Press 2008.
• H. Stuckenschmidt and F. van Harmelen. Information Sharing on the Semantic Web, Springer 2004.
• T. Berners-Lee. Weaving the Web, HarperCollins 2000
• T.R. Gruber, Toward principles for the design of ontologies used or knowledge sharing? , Int. J. Hum.-Comput. Stud., vol. 43, no. 5-6,1995
• D. Fensel et al., On2broker: Semantic-Based Access to Information Sources at the WWW
• V. Bush "As We May Think" The Atlantic Monthly, July, 1945. Re-print available online: http://www.theatlantic.com/doc/194507/bush (last accessed on 18.03.2009)
• RDFa in XHTML: Syntax and Processing, W3C Recommendation, http://www.w3.org/TR/rdfa-syntax/ (last accessed on 18.03.2009)
• GRDDL Primer, http://www.w3.org/TR/grddl-primer/ (last accessed on 19.03.2009)
• Yahoo SearchMonkey, http://developer.yahoo.com/searchmonkey/
• T. Berners-Lee “Linked Data Principles”, http://www.w3.org/DesignIssues/LinkedData.html (last accessed on 19.03.2009)
• C. Bizer, R. Cyganiak, and T. Heath “How to Publish Linked Data on the Web”, http://www4.wiwiss.fu-berlin.de/bizer/pub/LinkedDataTutorial/ (last accessed on 19.03.2009)
• K. Siorpaes, and M.Hepp: “OntoGame: Weaving the Semantic Web by Online Games”, 2008.
• Peter Mika. Ontologies are us: A unfied model of social networks and semantics. volume LNCS 3729. Springer, 2005.
• S. Schaffert. Ikewiki: A semantic wiki for collaborative knowledge management. June 2006.
• M. Völkel, M. Krötzsch, Denny Vrandecic, and H. Haller. Semantic wikipedia. May 23-26, 2006.

Tutorial

Abstract

The aim of this seminar (PS) is to further explore the topics discussed in the Semantic Web lectures by answering questions and solving problems directly related to Semantic Web, Semantic Annotations for Web content, Semantic Web languages, storage and query facilities, etc. The seminar follows closely the lecture's material. Exercise sheets will be handed out each week. Students will present their solutions the following week.

Tutorials