This paper addresses the challenge of applying Semantic Web technologies like OWL-DL reasoners to XML documents to find implied relationships not stated directly in the documents. The challenge comes because the structure of XML schema often contains implicit assumptions about taxonomy and relationships. This makes it difficult to implement a completely general and automated mechanism to transf...

This chapter gives an overview of the description logics underlying the OWL 2 Web Ontology Language and its three tractable profiles, OWL 2 RL, OWL 2 EL and OWL 2 QL. We consider the syntax and semantics of these description logics as well as main reasoning tasks and their computational complexity. We also discuss the semantical foundations for first-order and datalog rewritings of conjunctive ...

Two of the most common ways of processing and manipulating OWL ontologies are through an ontology editing environment (e.g. Protege or TopBraid) or via a programmatic interface, such as the OWL API. A complementary method is to use an OWL-aware command line shell. Posh, the Prolog OWL Shell is an interactive toplevel readeval-print-loop interface that provides powerful capabilities for querying...

In this paper, we present a brief overview of Pellet: a complete OWL-DL reasoner with acceptable to very good performance, extensive iddleware, and a number of unique features. Pellet is the first sound and complete OWL-DL reasoner with extensive support for reasoning ith individuals (including nominal support and conjunctive query), user-defined datatypes, and debugging support for ontologies....

This paper describes a new syntax that can be used to write OWL 2 ontologies. The syntax, which is known as TEX-OWL, was developed to address the need for an easy-to-read and easy-to-write plain text syntax. TEX-OWL is inspired by LTEX syntax, and covers all construct of OWL 2. We designed TEXOWL to be less verbose than the other OWL syntaxes, and easy-to-use especially for quickly developing s...

In this demonstration we will show two prototypes based on the BRMS (Business Rule Management System) WODM, (1) The OWL plug-in and (2) the change-management plug-in. The OWL plugin enables authoring and executing business rules over OWL ontologies. It consists of importing OWL ontologies into WODM and using the all the functionalities offered by this BRMS to author and execute rules. The chang...

This is the eleventh in a series of articles on ontology-based approaches to modeling. The main focus is on popular ontology languages proposed for the Semantic Web, such as the Resource Description Framework (RDF), RDF Schema (RDFS), and the Web Ontology Language (OWL). OWL is based on description logic. A later series of articles will explore other logic-based languages such as datalog. The f...

The problem of exchanging knowledge bases from a source signature to a target signature connected through a mapping has recently attracted attention in knowledge representation. In this paper, we study this problem for knowledge bases and mappings expressed in OWL 2 QL, one of the profiles of the standard Web Ontology Language OWL 2. More specifically, we consider the membership and non-emptine...

We present a novel rewriting technique for conjunctive query answering over OWL 2 QL ontologies. In general, the obtained rewritings are not necessarily correct and can be of exponential size in the length of the query. We argue, however, that in most, if not all, practical cases the rewritings are correct and of polynomial size. Moreover, we prove some sufficient conditions, imposed on queries...