Diese Datenbank enthält über 40.000 Dokumente zu Themen aus den Bereichen Formalerschließung – Inhaltserschließung – Information Retrieval.
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1Gómez-Pérez, A. ; Corcho, O.: Ontology languages for the Semantic Web.
In: IEEE intelligent systems 2002, Jan./Feb., S.54-60.
Abstract: Ontologies have proven to be an essential element in many applications. They are used in agent systems, knowledge management systems, and e-commerce platforms. They can also generate natural language, integrate intelligent information, provide semantic-based access to the Internet, and extract information from texts in addition to being used in many other applications to explicitly declare the knowledge embedded in them. However, not only are ontologies useful for applications in which knowledge plays a key role, but they can also trigger a major change in current Web contents. This change is leading to the third generation of the Web-known as the Semantic Web-which has been defined as "the conceptual structuring of the Web in an explicit machine-readable way."1 This definition does not differ too much from the one used for defining an ontology: "An ontology is an explicit, machinereadable specification of a shared conceptualization."2 In fact, new ontology-based applications and knowledge architectures are developing for this new Web. A common claim for all of these approaches is the need for languages to represent the semantic information that this Web requires-solving the heterogeneous data exchange in this heterogeneous environment. Here, we don't decide which language is best of the Semantic Web. Rather, our goal is to help developers find the most suitable language for their representation needs. The authors analyze the most representative ontology languages created for the Web and compare them using a common framework.
Inhalt: Vgl.: http://oa.upm.es/2646/1/JCR01.pdf.
Themenfeld: Wissensrepräsentation ; Semantic Web
Objekt: XOL ; SHOE ; OML ; RDF ; DAML ; OIL
2Antoniou, G. ; Harmelen, F. van: ¬A semantic Web primer.
Cambridge, MA : MIT Press, 2004. 236 S.
(Cooperative information systems)
Abstract: The development of the Semantic Web, with machine-readable content, has the potential to revolutionise the World Wide Web and its use. A Semantic Web Primer provides an introduction and guide to this emerging field, describing its key ideas, languages and technologies. Suitable for use as a textbook or for self-study by professionals, it concentrates on undergraduate-level fundamental concepts and techniques that will enable readers to proceed with building applications on their own. It includes exercises, project descriptions and annotated references to relevant online materials. A Semantic Web Primer is the only available book on the Semantic Web to include a systematic treatment of the different languages (XML, RDF, OWL and rules) and technologies (explicit metadata, ontologies and logic and interference) that are central to Semantic Web development. The book also examines such crucial related topics as ontology engineering and application scenarios. After an introductory chapter, topics covered in succeeding chapters include XML and related technologies that support semantic interoperability; RDF and RDF Schema, the standard data model for machine-processable semantics; and OWL, the W3C-approved standard for a Web ontology language more extensive than RDF Schema; rules, both monotonic and nonmonotonic, in the framework of the Semantic Web; selected application domains and how the Semantic Web would benefit them; the development of ontology-based systems; and current debates on key issues and predictions for the future.
Anmerkung: Rez. in: JASIST 57(2006) no.8, S.1132-1133 (H. Che): "The World Wide Web has been the main source of an important shift in the way people communicate with each other, get information, and conduct business. However, most of the current Web content is only suitable for human consumption. The main obstacle to providing better quality of service is that the meaning of Web content is not machine-accessible. The "Semantic Web" is envisioned by Tim Berners-Lee as a logical extension to the current Web that enables explicit representations of term meaning. It aims to bring the Web to its full potential via the exploration of these machine-processable metadata. To fulfill this, it pros ides some meta languages like RDF, OWL, DAML+OIL, and SHOE for expressing knowledge that has clear, unambiguous meanings. The first steps in searing the Semantic Web into the current Web are successfully underway. In the forthcoming years, these efforts still remain highly focused in the research and development community. In the next phase, the Semantic Web will respond more intelligently to user queries. The first chapter gets started with an excellent introduction to the Semantic Web vision. At first, today's Web is introduced, and problems with some current applications like search engines are also covered. Subsequently, knowledge management. business-to-consumer electronic commerce, business-to-business electronic commerce, and personal agents are used as examples to show the potential requirements for the Semantic Web. Next comes the brief description of the underpinning technologies, including metadata, ontology, logic, and agent. The differences between the Semantic Web and Artificial Intelligence are also discussed in a later subsection. In section 1.4, the famous "laser-cake" diagram is given to show a layered view of the Semantic Web. From chapter 2, the book starts addressing some of the most important technologies for constructing the Semantic Web. In chapter 2, the authors discuss XML and its related technologies such as namespaces, XPath, and XSLT. XML is a simple, very flexible text format which is often used for the exchange of a wide variety of data on the Web and elsewhere. The W3C has defined various languages on top of XML, such as RDF. Although this chapter is very well planned and written, many details are not included because of the extensiveness of the XML technologies. Many other books on XML provide more comprehensive coverage. ; The next chapter introduces resource description framework (RDF) and RDF schema (RDFS). Unlike XML, RDF provides a foundation for expressing the semantics of dada: it is a standard dada model for machine-processable semantics. Resource description framework schema offers a number of modeling primitives for organizing RDF vocabularies in typed hierarchies. In addition to RDF and RDFS, a query language for RDF, i.e. RQL. is introduced. This chapter and the next chapter are two of the most important chapters in the book. Chapter 4 presents another language called Web Ontology Language (OWL). Because RDFS is quite primitive as a modeling language for the Web, more powerful languages are needed. A richer language. DAML+OIL, is thus proposed as a joint endeavor of the United States and Europe. OWL takes DAML+OIL as the starting point, and aims to be the standardized and broadly accepted ontology language. At the beginning of the chapter, the nontrivial relation with RDF/RDFS is discussed. Then the authors describe the various language elements of OWL in some detail. Moreover, Appendix A contains an abstract OWL syntax. which compresses OWL and makes OWL much easier to read. Chapter 5 covers both monotonic and nonmonotonic rules. Whereas the previous chapter's mainly concentrate on specializations of knowledge representation, this chapter depicts the foundation of knowledge representation and inference. Two examples are also givwn to explain monotonic and non-monotonic rules, respectively. "To get the most out of the chapter. readers had better gain a thorough understanding of predicate logic first. Chapter 6 presents several realistic application scenarios to which the Semantic Web technology can be applied. including horizontal information products at Elsevier, data integration at Audi, skill finding at Swiss Life, a think tank portal at EnerSearch, e-learning. Web services, multimedia collection indexing, online procurement, raid device interoperability. These case studies give us some real feelings about the Semantic Web. ; The chapter on ontology engineering describes the development of ontology-based systems for the Web using manual and semiautomatic methods. Ontology is a concept similar to taxonomy. As stated in the introduction, ontology engineering deals with some of the methodological issues that arise when building ontologies, in particular, con-structing ontologies manually, reusing existing ontologies. and using semiautomatic methods. A medium-scale project is included at the end of the chapter. Overall the book is a nice introduction to the key components of the Semantic Web. The reading is quite pleasant, in part due to the concise layout that allows just enough content per page to facilitate readers' comprehension. Furthermore, the book provides a large number of examples, code snippets, exercises, and annotated online materials. Thus, it is very suitable for use as a textbook for undergraduates and low-grade graduates, as the authors say in the preface. However, I believe that not only students but also professionals in both academia and iudustry will benefit from the book. The authors also built an accompanying Web site for the book at http://www.semanticwebprimer.org. On the main page, there are eight tabs for each of the eight chapters. For each tabm the following sections are included: overview, example, presentations, problems and quizzes, errata, and links. These contents will greatly facilitate readers: for example, readers can open the listed links to further their readings. The vacancy of the errata sections also proves the quality of the book."
Themenfeld: Semantic Web ; Grundlagen u. Einführungen: Allgemeine Literatur
Objekt: WWW ; RDF ; RDFS ; DAML+OIL ; OWL
LCSH: Semantic Web
DDC: 025.04 / dc22
3Fensel, D. ; Harmelen, F. van ; Horrocks, I.: OIL and DAML+OIL : ontology languages for the Semantic Web.
In: Towards the semantic Web: ontology-driven knowledge management. Eds.: J. Davies, u.a. Chichester : Wiley, 2004. S.11-31.
Abstract: This chapter discusses OIL and DAML1OIL, currently the most prominent ontology languages for the Semantic Web. The chapter starts by discussing the pyramid of languages that underlie the architecture of the Semantic Web (XML, RDF, RDFS). In section 2.2, we briefly describe XML, RDF and RDFS. We then discuss in more detail OIL and DAML1OIL, the first proposals for languages at the ontology layer of the semantic pyramid. For OIL (and to some extent DAML1OIL) we discuss the general design motivations (Section 2.3), describe the constructions in the language (Section 2.4), and the various syntactic forms of these languages (Section 2.5). Section 2.6 discusses the layered architecture of the language, section 2.7 briefly mentions the formal semantics, section 2.8 discusses the transition from OIL to DAML+OIL, and section 2.9 concludes with our experience with the language to date and future development in the context of the World Wide Web Consortium (W3C). This chapter is not intended to give full and formal definitions of either the syntax or the semantics of OIL or DAML1OIL. Such definitions are already available elsewhere: http://www.ontoknowledge.org/oil/ for OIL and http://www.w3.org/submission/2001/12/ for DAML1OIL.
Themenfeld: Semantic Web ; Wissensrepräsentation
Objekt: DAML ; OIL
4Roth, A.: Modellierung und Anwendung von Ontologien am Beispiel "Operations Research & Management Science".
Paderborn, 2002. II, 26 S.
Abstract: In der Praxis werden häufig verteilte Informationssysteme eingesetzt, die eine semantische Heterogenität aufweisen. Diese besteht in erster Linie darin, dass unabhängig entwickelte Systeme mit verschiedenen statischen Datenmodellen (Schemata) operieren, die auch bei teilweiser inhaltlicher Übereinstimmung miteinander gar nicht oder nur mit einem erheblichen manuellen Aufwand kombiniert werden können. Eine solche Datenkopplung von n Informationssystemen würde ein Schnittstellensystem der Größe n(n-1) bedeuten, welches verwaltet werden müsste. Das größte Problem bei verteilten Informationssystemen ist die Heterogenität, bedingt durch inkompatible Kommunikationsprotokolle, Abfragesprachen, interne Repräsentation usw. Obwohl die Interoperabilität zwischen Systemen u.a. durch Standardschnittstellen (z.B. JDBC) und systemneutralen Austauschformaten (z.B. XML) verbessert werden kann, bleibt das schwierige Problem der semantischen Homogenität zu lösen. In dieser Seminararbeit soll ein solches Modell für die Domäne "Operations Research & Management Science" konzipiert und in einem prototypischen Systemumfeld angewendet werden. Als konzeptionelle Grundlage zur Datenmodellierung dient dabei das Resource Description Framework (RDF). Das Datenmodell wird XML-basiert realisiert und in einer speziellen Datenbank nach dem Netzwerkmodell gehalten. Dadurch, dass die in XML semantisch ausgezeichneten Wissensobjekte maschinell verarbeitet werden können, können aus diesem Netzwerk alle benötigten Informationen extrahiert und für eine detaillierte Recherche aufbereitet werden. Die Seminararbeit beschreibt die grundlegende Konzeptionierung und die Erfahrungen mit der eingesetzten Technologie, die bei der prototypischen Umsetzung gesammelt wurden.
Inhalt: Vgl. auch unter: http://dsor.upb.de/~aroth/rdfdb/RDFOntologien.pdf.
Objekt: RDF ; DAML ; TouchGraph
5Shah, U. ; Finin, T. ; Joshi, A. ; Cost, R.S. ; Mayfield, J.: Information retrieval on the Semantic Web.
Abstract: We describe an apporach to retrieval of documents that consist of both free text and semantically enriched markup. In particular, we present the design and implementation prototype of a framework in which both documents and queries can be marked up with statements in the DAML+OIL semantic web language. These statement provide both structured and semi-structured information about the documents and their content. We claim that indexing text and semantic markup will significantly improve retrieval performance. Outr approach allows inferencing to be done over this information at several points: when a document is indexed,when a query is processed and when query results are evaluated.
Themenfeld: Semantic Web
Objekt: DAML ; OIL