http://www.cs.man.ac.uk/~horrocks/Publications/download/2003/HoPH03a.pdf

From SHIQ and RDF to OWL: the making of a Web Ontology Language

The new Semantic Web recommendations for RDF, RDFS and OWL have, at their heart, the RDF graph. Jena2, a second-generation RDF toolkit, is similarly centered on the RDF graph. RDFS and OWL reasoning are seen as graph-to-graph transforms, producing graphs of virtual triples. Rich APIs are provided. The Model API includes support for other aspects of the RDF recommendations, such as containers and reification. The Ontology API includes support for RDFS and OWL, including advanced OWL Full support. Jena includes the de facto reference RDF/XML parser, and provides RDF/XML output using the full range of the rich RDF/XML grammar. N3 I/O is supported. RDF graphs can be stored in-memory or in databases. Jena's query language, RDQL, and the Web API are both offered for the next round of standardization.

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Jena: implementing the semantic web recommendations

We introduce the OWL Plugin, a Semantic Web extension of the Protege ontology development platform. The OWL Plugin can be used to edit ontologies in the Web Ontology Language (OWL), to access description logic reasoners, and to acquire instances for semantic markup. In many of these features, the OWL Plugin has created and facilitated new practices for building Semantic Web contents, often driven by the needs of and feedback from our users. Furthermore, Protege's flexible open-source platform means that it is easy to integrate custom-tailored components to build real-world applications. This document describes the architecture of the OWL Plugin, walks through its most important features, and discusses some of our design decisions.

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The protégé OWL plugin: an open development environment for semantic web applications

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.

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Description logic programs: combining logic programs with description logic

An important objective of the Semantic Web is to make Electronic Commerce interactions more flexible and automated. To achieve this, standardization of ontologies, message content and message protocols will be necessary.In this paper we investigate how Semantic and Web Services technologies can be used to support service advertisement and discovery in e-commerce. In particular, we describe the design and implementation of a service matchmaking prototype which uses a DAML-S based ontology and a Description Logic reasoner to compare ontology based service descriptions. We also present the results of initial experiments testing the performance of this prototype implementation in a realistic agent based e-commerce scenario.

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A software framework for matchmaking based on semantic web technology

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.

https://assets.cambridge.org/97805218/76254/frontmatter/9780521876254_frontmatter.pdf

The Description Logic Handbook

OWL Web Ontology Language Reference-W3C Recommen-dation

Ontology and other logical languages are built around the idea that axioms enable the inference of new facts about the available data. In some circumstances, however, the data is meant to be complete in certain ways, and deducing new facts may be undesirable. Previous approaches to this issue have relied on syntactically specifying certain axioms as constraints or adding in new constructs for constraints, and providing a different or extended meaning for constraints that reduces or eliminates their ability to infer new facts without requiring the data to be complete. We propose to instead directly state that the extension of certain concepts and roles are complete by making them DBox predicates, which eliminates the distinction between regular axioms and constraints for these concepts and roles. This proposal eliminates the need for special semantics and avoids problems of previous proposals.

/pdf/ontology-constraints-in-incomplete-and-complete-data-36bpvl2i6z.pdf

Ontology constraints in incomplete and complete data

In this article, eight people from different communities, including applications, description logics and frame logic, express their view of a Web ontology language. They had complete freedom in forming their statements, but they focused on these core questions: (1) What is the single most important property of a Web ontology language? (2) Taking a formal semantics for granted, should a Web ontology language be based on description logics such as OIL (Ontology Inference Layer) or DAML (DARPA Agent Markup Language) + OIL? (3) How should we communicate a Web ontology language to developers? Much has been said about the dire nature of a Web ontology language's standardization. This being so, where do its beauty and its excitements lie? The answer is KISSES - Keep It Straight, Simple and ExtenSible. There are, of course, different opinions. So what does this boil down to from the technical view? The authors tell you how ontologies' KISSES move them.

Ontologies' KISSES in standardization

EU-IST Network of Excellence (NoE) IST-2004-507482 KWEB Deliverable D2.5.5 (WP2.5) OWL 1.1 is a simple extension to the OWL DL species of the W3C OWL Web Ontology Language. OWL 1.1 has been designed to provide some interesting and useful expressive additions to OWL DL while retaining the desirable characteristics of OWL DL, including decidability and implementability. Keyword list: description logics, ontology language, RDF, OWL DL, OWL, W3C, standardization

http://www.knowledgeweb.semanticweb.org/semanticportal/deliverables/D2.5.5.pdf

Peter F. Patel-Schneider

Papers

The Description Logic Handbook

OWL Web Ontology Language Reference-W3C Recommen-dation

Ontology constraints in incomplete and complete data

Ontologies' KISSES in standardization

D2.5.5 Next Steps for OWL