THE WEB SERVICE MODELING LANGUAGE WSML: AN OVERVIEW <s> Introduction <s> This is the second edition of an account of the mathematical foundations of logic programming. Its purpose is to collect, in a unified and comprehensive manner, the basic theoretical results of the field, which have previously only been available in widely scattered research papers. In addition to presenting the technical results, the book also contains many illustrative examples and problems. The text is intended to be self-contained, the only prerequisites being some familiarity with PROLOG and knowledge of some basic undergraduate mathematics. The material is suitable either as a reference book for researchers or as a textbook for a graduate course on the theoretical aspects of logic programming and deductive database systems. <s> BIB001 </s> THE WEB SERVICE MODELING LANGUAGE WSML: AN OVERVIEW <s> Introduction <s> We propose a novel formalism, called Frame Logic (abbr., F-logic), that accounts in a clean and declarative fashion for most of the structural aspects of object-oriented and frame-based languages. These features include object identity, complex objects, inheritance, polymorphic types, query methods, encapsulation, and others. In a sense, F-logic stands in the same relationship to the object-oriented paradigm as classical predicate calculus stands to relational programming. F-logic has a model-theoretic semantics and a sound and complete resolution-based proof theory. A small number of fundamental concepts that come from object-oriented programming have direct representation in F-logic; other, secondary aspects of this paradigm are easily modeled as well. The paper also discusses semantic issues pertaining to programming with a deductive object-oriented language based on a subset of F-logic. <s> BIB002 </s> THE WEB SERVICE MODELING LANGUAGE WSML: AN OVERVIEW <s> Introduction <s> The authors propose the markup of Web services in the DAML family of Semantic Web markup languages. This markup enables a wide variety of agent technologies for automated Web service discovery, execution, composition and interoperation. The authors present one such technology for automated Web service composition. <s> BIB003 </s> THE WEB SERVICE MODELING LANGUAGE WSML: AN OVERVIEW <s> Introduction <s> This second editionsystematically introduces the notion of ontologies to the non-expert reader and demonstrates in detail how to apply this conceptual framework for improved intranet retrieval of corporate information and knowledge and for enhanced Internet-based electronic commerce. He also describes ontology languages (XML, RDF, and OWL) and ontology tools, and the application of ontologies. In addition to structural improvements, the second edition covers recent developments relating to the Semantic Web, and emerging web-based standard languages. <s> BIB004 </s> THE WEB SERVICE MODELING LANGUAGE WSML: AN OVERVIEW <s> Introduction <s> We show how to interoperate, semantically and inferentially, between the leading Semantic Web approaches to rules (RuleML Logic Programs) and ontologies (OWL/DAML+OIL Description Logic) via analyzing their expressive intersection. To do so, we define a new intermediate knowledge representation (KR) contained within this intersection: Description Logic Programs (DLP), and the closely related Description Horn Logic (DHL) which is an expressive fragment of first-order logic (FOL). DLP provides a significant degree of expressiveness, substantially greater than the RDF-Schema fragment of Description Logic. We show how to perform DLP-fusion: the bidirectional translation of premises and inferences (including typical kinds of queries) from the DLP fragment of DL to LP, and vice versa from the DLP fragment of LP to DL. In particular, this translation enables one to "build rules on top of ontologies": it enables the rule KR to have access to DL ontological definitions for vocabulary primitives (e.g., predicates and individual constants) used by the rules. Conversely, the DLP-fusion technique likewise enables one to "build ontologies on top of rules": it enables ontological definitions to be supplemented by rules, or imported into DL from rules. It also enables available efficient LP inferencing algorithms/implementations to be exploited for reasoning over large-scale DL ontologies. <s> BIB005 </s> THE WEB SERVICE MODELING LANGUAGE WSML: AN OVERVIEW <s> Introduction <s> This introduction presents the main motivations for the development of Description Logics (DLs) as a formalism for representing knowledge, as well as some important basic notions underlying all systems that have been created in the DL tradition. In addition, we provide the reader with an overview of the entire book and some guidelines for reading it. We first address the relationship between Description Logics and earlier semantic network and frame systems, which represent the original heritage of the field. We delve into some of the key problems encountered with the older efforts. Subsequently, we introduce the basic features of DL languages and related reasoning techniques. DL languages are then viewed as the core of knowledge representation systems, considering both the structure of a DL knowledge base and its associated reasoning services. The development of some implemented knowledge representation systems based on Description Logics and the first applications built with such systems are then reviewed. Finally, we address the relationship of Description Logics to other fields of Computer Science.We also discuss some extensions of the basic representation language machinery; these include features proposed for incorporation in the formalism that originally arose in implemented systems, and features proposed to cope with the needs of certain application domains. <s> BIB006
Web Services are pieces of functionality which are accessible over the Web. Current Web Service technologies allow to describe the functionality offered by a Web Service on a syntactical level only. For automation of tasks, such as Web Service discovery, composition and execution, semantic description of Web Services is required. Semantic Web technology enables formal description of Web content. A combination of Semantic Web with Web Service technology allows the formal description of Web Services. This combination is also called Semantic Web Services  BIB003 . In this context, the Web Service Modeling Ontology WSMO  provides a conceptual model for the description of various aspects related to Semantic Web Services. In particular, WSMO distinguishes four top-level elements: Ontologies Ontologies BIB004 provide formal and explicit specifications of the vocabularies used by the other modeling elements. Such formal specifications enable automated processing of WSMO descriptions and provide background knowledge for Goal and Web Service descriptions. Goals Goals describe the functionality and interaction style from the requester perspective. Web Service descriptions Web Service descriptions specify the functionality and the means of interacting with the Web Service in order to achieve the requested functionality. Mediators Mediators connect different WSMO elements and resolve heterogeneity in data representation, interaction style and business processes. With WSML we provide a formal Web language based on the conceptual model of WSMO. The goal of WSML is to provide one coherent framework which brings together Web technologies with different wellknown logical language paradigms in order to enable the description of Semantic Web Services. We take Description Logics BIB006 , Logic Programming BIB001 , and F-Logic BIB002 , as starting points for the development of a number of WSML language variants. The core language is based on the intersection of Description Logics and Logic Programming BIB005 . This core language is extended in the directions of the mentioned language paradigms. Syntax-wise, WSML takes the user point of view with on the one hand its syntax for conceptual modeling and on the other hand allows full flexibility to specify arbitrary logical axioms and constraints using the logical expression syntax. 1 We give an overview of WSML and its language layering in Section 2. The normative human-readable syntax of WSML is described in Section 3. The key features of WSML are described in Section 4. Section 5 describes related approaches for the description of Semantic Web Services and Ontologies. We draw conclusions and outline future work in Section 6.