Description Logics as Ontology Languages for the Semantic Web

The vision of a Semantic Web has recently drawn considerable attention, both from academia and industry. Description logics are often named as one of the tools that can support the Semantic Web and thus help to make this vision reality. In this paper, we describe what description logics are and what they can do for the Semantic Web. Descriptions logics are very useful for defining, integrating, and maintaining ontologies, which provide the Semantic Web with a common understanding of the basic semantic concepts used to annotate Web pages. We also argue that, without the last decade of basic research in this area, description logics could not play such an important rˆole in this domain

Automatic Transformation of Relational Database Schema into OWL Ontologies

Ontology alignment, or ontology matching, is a technique to map different concepts between ontologies. For this purpose at least two ontologies are required. In certain scenarios, such as data integration, heterogeneous database integration and data model compatibility evaluation, a need to transform a relational database schema to an ontology can arise. To conduct a successful transformation it is necessary to identify the differences between relational database schema and ontology information representation methods, and then to define transformation rules. The most straight forward but time consuming way to carry out transformation is to do it manually. Often this is not an option due to the size of data to be transformed. For this reason there is a need for an automated solution.The automatic transformation of OWL ontology from relational database schema is presented in this paper; the data representation differences between relational database schema and OWL ontologies are described; the transformation rules are defined and the transformation tool’s prototype is developed to perform the described transformation

Racer: A Core Inference Engine for the Semantic Web

In this paper we describe Racer, which can be considered as a core inference engine for the semantic web. The Racer inference server o#ers two APIs that are already used by at least three di#erent network clients, i.e., the ontology editor OilEd, the visualization tool RICE, and the ontology development environment Protege 2. The Racer server supports the standard DIG protocol via HTTP and a TCP based protocol with extensive query facilities. Racer currently supports the web ontology languages DAML+OIL, RDF, and OWL

Web ontology representation and reasoning via fragments of set theory

In this paper we use results from Computable Set Theory as a means to represent and reason about description logics and rule languages for the semantic web. Specifically, we introduce the description logic \mathcal{DL}\langle 4LQS^R\rangle(\D)--admitting features such as min/max cardinality constructs on the left-hand/right-hand side of inclusion axioms, role chain axioms, and datatypes--which turns out to be quite expressive if compared with \mathcal{SROIQ}(\D), the description logic underpinning the Web Ontology Language OWL. Then we show that the consistency problem for \mathcal{DL}\langle 4LQS^R\rangle(\D)-knowledge bases is decidable by reducing it, through a suitable translation process, to the satisfiability problem of the stratified fragment $4LQS^R$ of set theory, involving variables of four sorts and a restricted form of quantification. We prove also that, under suitable not very restrictive constraints, the consistency problem for \mathcal{DL}\langle 4LQS^R\rangle(\D)-knowledge bases is \textbf{NP}-complete. Finally, we provide a $4LQS^R$-translation of rules belonging to the Semantic Web Rule Language (SWRL)

Une approche d'ontologie pour la modélisation des connaissances et l’interrogation des capteurs de réseaux sans fil

International audienceWireless sensor networks (WSNs) generate large volumes of raw data which increases the difficulty for applications to manage and query sensor data. WSNs are normally application specific with no sharing or reusability of sensor data among applications. In order for applications to be developed independently of particular WSNs, sensor data need to be enriched with semantic information. Ontologies are widely used as a means for solving the information heterogeneity problems because of their capability to provide explicit meaning to the information. This paper presents our work towards the development of a wireless sensor network ontology. Based on the proposed ontology we use the SPARQL query language to enable querying of sensor data. We present the description of the development of the proposed ontology, partial evaluation of the early prototype ontology, a discussion of design and implementation issues, and directions for future research works.Les réseaux de capteurs sans fil (WSN) génèrent de gros volumes de données brutes, ce qui complique la gestion et l'interrogation des données des capteurs par les applications. Les WSN sont normalement spécifiques à une application, sans partage ni possibilité de réutilisation des données de capteur entre les applications. Pour que les applications puissent être développées indépendamment de certains WSN, les données des capteurs doivent être enrichies d'informations sémantiques. Les ontologies sont largement utilisées pour résoudre les problèmes d'hétérogénéité de l'information en raison de leur capacité à donner un sens explicite à l'information. Cet article présente nos travaux en vue du développement d’une ontologie de réseau de capteurs sans fil. Sur la base de l'ontologie proposée, nous utilisons le langage de requête SPARQL pour permettre l'interrogation des données du capteur. Nous présentons la description du développement de l'ontologie proposée, une évaluation partielle de l'ontologie du prototype initial, une discussion des problèmes de conception et de mise en œuvre et des orientations pour les travaux de recherche futurs