The best informal de?nition of the Semantic Web is maybe found in the May 2001Scienti?cAmericanarticle“TheSemanticWeb”(Berners-Leeetal. ),which says“TheSemanticWebisanextensionofthecurrentWebinwhichinformation is given well-de?ned meaning, better enabling computers and people to work in cooperation. ” People who work on the Semantic Web quite often base their work on the famous “semantic web tower”, a product of Tim Berners-Lee’s inspiring drawing on whiteboards. The lowest level is the level of character representation (Unicode) and the identi?cation of resources on the Web (URIs). The highest level concerns the problem of trusting information on the Web. Somewhere in the middle of the tower is the logic level. It addresses the problem of represe- ing information on the Web in a way so that inference rules can derive implicit information from explicitly stated information. The workshop “Principles and Practices of Semantic Web Reasoning” (PPSWR 2004) addressed problems on this level. It took place in September 2004 as a satellite event of the 20th Int- national Conference on Logic Programming (ICLP) in St. Malo, France. After PPSWR 2003 in Mumbai, India, it was the second workshop in this series. This book contains the articles presented at the workshop.

Here are the proceedings of the 4th International Workshop on Principles and Practice of Semantic Web Reasoning, PPSWR 2006. The book presents 14 revised full papers together with 1 invited talk and 6 system demonstrations, addressing major aspects of semantic Web research, namely forms of reasoning with a strong interest in rule-based languages and methods. Coverage includes theoretical work on reasoning methods, concrete reasoning methods and query languages, and practical applications.

The Semantic Web is a major endeavor aimed at enriching the existing Web withmetadataandprocessingmethodssoastoprovideWeb-basedsystemswith advanced(so-calledintelligent)capabilities, inparticularwithcontext-awareness and decision support. The advanced capabilities striven for in most Semantic Web application s- narios primarily call for reasoning. Reasoning capabilities are o?ered by exi- ing Semantic Web languages, such as BPEL4WS, BPML, ConsVISor, DAML-S, JTP, TRIPLE, and others. These languages, however, were developed mostly from functionality-centered (e.g., ontology reasoning or access validation) or application-centered (e.g., Web service retrieval and composition) perspectives. A perspective centered on the reasoning techniques (e.g., forward or backward chaining, tableau-like methods, constraint reasoning, etc.) complementing the above-mentioned activities appears desirable for Semantic Web systems and - plications. The workshop on "Principles and Practice of Semantic Web Reas- ing," which took place on December 8, 2003, in Mumbai, India, was the?rst of a series of scienti?c meetings devoted to such a perspective. JustasthecurrentWebisinherentlyheterogeneousindataformatsanddata semantics, the Semantic Web will be inherently heterogeneous in its reasoning forms. Indeed, anysingleformof reasoningturnsouttobeirrealin theSemantic Web. For example, ontology reasoning in general relies on monotonic negation (for the metadata often can be fully speci?ed), while databases, Web databases, and Web-based information systems call for non-monotonic reasoning (for one would not specify non-existing trains in a railway timetable); constraint reas- ing is needed when dealing with time (for time intervals have to be dealt with), while(forwardand/orbackward)chainingisthereasoningofchoicewhencoping with database-like views (for views, i.e., virtual data, can be derived from actual data using operations such as join and projections)

This book constitutes the refereed proceedings of the Third International Workshop on Principles and Practice of Semantic Web Reasoning, PPSWR 2005, held in Dagstuhl Castle, Germany in September 2005. The 12 revised full papers presented together with 3 invited contributions were carefully reviewed and selected for inclusion in the book. The major aspects of semantic Web research are addressed in the papers, namely semantic Web architectures, language issues, and formal reasoning methods. The advances are investigated in the context of new design principles and challenging applications.

This book presents thoroughly arranged tutorial papers corresponding to lectures given by leading researchers at the Second International Summer School on Reasoning Web in Lisbon, Portugal, in September 2006. Building on the predessor school held in 2005 and published as LNCS 3564, the ten tutorial lectures presented provide competent coverage of current topics in semantic Web research and development.

This volume contains the tutorial papers of the Summer School “Reasoning Web,”July25–29,2005(http://reasoningweb. org). TheSchoolwashostedbythe University of Malta and was organized by the Network of Excellence REWERSE “Reasoning on the Web with Rules and Semantics” (http://rewerse. net), funded by the EU Commission and by the Swiss Federal O?ce for Edu- tion and Science within the 6th Framework Programme under the project ref- ence number 506779. The objective of the school was to provide an introduction into methods and issues of the Semantic Web, a major endeavor in current Web research, where the World Wide Web Consortium W3C plays an important role. The main idea of the Semantic Web is to enrich Web data with meta-data carrying a “meaning” of the data and allowing Web-based systems to reason about data (and meta-data). The meta-data used in Semantic Web applications is usually linked to a conceptualization of the application domain shared by di?erent applications. Such a conceptualization is called an ontology and sp- i?es classes of objects and relations between them. Ontologies are de?ned by ontology languages, based on logic and supporting formal reasoning. Just as the current Web is inherently heterogeneous in data formats and data semantics, the Semantic Web will be inherently heterogeneous in its reasoning forms. - deed, any single form of reasoning turns out to be insu?cient in the Semantic Web.

"This book addresses the Semantic Web from an operative point of view using theoretical approaches, methodologies, and software applications as innovative solutions to true knowledge management"--Provided by publisher.

This book constitutes the refereed proceedings of the 16th International Symposium on Methodologies for Intelligent Systems, ISMIS 2006. The book presents 81 revised papers together with 3 invited papers. Topical sections include active media human-computer interaction, computational intelligence, intelligent agent technology, intelligent information retrieval, intelligent information systems, knowledge representation and integration, knowledge discovery and data mining, logic for AI and logic programming, machine learning, text mining, and Web intelligence.

Just like the industrial society of the last century depended on natural resources, today’s society depends on information and its exchange. Staab and Stuckenschmidt structured the selected contributions into four parts: Part I, "Data Storage and Access", prepares the semantic foundation, i.e. data modelling and querying in a flexible and yet scalable manner. These foundations allow for dealing with the organization of information at the individual peers. Part II, "Querying the Network", considers the routing of queries, as well as continuous queries and personalized queries under the conditions of the permanently changing topological structure of a peer-to-peer network. Part III, "Semantic Integration", deals with the mapping of heterogeneous data representations. Finally Part IV, "Methodology and Systems", reports experiences from case studies and sample applications. The overall result is a state-of-the-art description of the potential of Semantic Web and peer-to-peer technologies for information sharing and knowledge management when applied jointly.