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.

Let C 2 p denote the class of first order sentences with two variables and with additional quantifiers "there exists exactly (at most, at least) i", for i p, and let C 2 be the union of C 2 p taken over all integers p. We prove that the satisfiability problem for C 2 1 sentences is NEXPTIME-complete. This strengthens the results by E. Grädel, Ph. Kolaitis and M. Vardi [15] who showed that the satisfiability problem for the first order two-variable logic L 2 is NEXPTIME-complete and by E. Grädel, M. Otto and E. Rosen [16] who proved the decidability of C 2 . Our result easily implies that the satisfiability problem for C 2 is in non-deterministic, doubly exponential time. It is interesting that C 2 1 is in NEXPTIME in spite of the fact, that there are sentences whose minimal (and only) models are of doubly exponential size. It is worth noticing, that by a recent result of E. Gradel, M. Otto and E. Rosen [17], extensions of two-variables logic L 2 by a week access to car...

Today’s economy exhibits a growing trend toward highly specialized solution providers cooperatively offering configurable products and services to their customers. This paradigm shift requires the extension of current standalone configuration technology with capabilities of knowledge sharing and distributed problem solving. In this context a standardized configuration knowledge representation language with formal semantics is needed in order to support knowledge interchange between different configuration environments. Languages such as Ontology Inference Layer (OIL) and DARPA Agent Markup Language (DAML+OIL) are based on such formal semantics (description logic) and are very popular for knowledge representation in the Semantic Web. In this paper we analyze the applicability of those languages with respect to configuration knowledge representation and discuss additional demands on expressivity. For joint configuration problem solving it is necessary to agree on a common problem definition. Therefore, we give a description logic based definition of a configuration problem and show its equivalence with existing consistency-based definitions, thus joining the two major streams in knowledge-based configuration (description logics and predicate

A computational model of children's semantic memory is built from the Latent Semantic Analysis (LSA) of a multisource child corpus. Three tests of the model are described, simulating a vocabulary test, an association test and a recall task. For each one, results from experiments with children are presented and compared to the model data.

In this chapter we emphasize how we can integrate Web-based sales systems for highly complex customizable products and services by making use of the descriptive representation formalisms of the Semantic Web. Building on the equivalence between the consistency based definition and the description logic based definition of configuration [1], we are capable of transforming our application domain-independent meta-model for modeling configuration knowledge [2] into the emerging standards of the Semantic Web initiative, such as DAML+OIL. Furthermore, we discuss how these standardized description languages can be used to derive capability descriptions for semantic configuration Web services. 1

Product configuration is a major commercial application of knowledge-based systems, and joint configuration by multiple business partners is becoming a key application in today's highly specialized economy. The required integration of configuration knowledge is a challenging task due to the variety of knowledge representation formalisms used in commercial configurators. Ontology languages such as DAML+OIL provide an infrastructure for the Semantic Web with the goal of intelligent information integration. The aim of this paper is to show the applicability of such languages for building configuration knowledge bases. We join the two major streams in knowledge-based configuration (description logics on one hand and predicate logic, including constraint-based and resource-balancing techniques on the other) by giving a description logic based definition of a configuration task and showing its equivalence with existing consistency-based definitions. We show that Semantic Web ontology languages can be applied to configuration by formalizing language elements relevant for building configuration knowledge bases and discuss extensions needed in order to provide full fledged configuration knowledge representation. The result is a common basis for current configuration approaches on the Semantic Web that is necessary for the provision of joint configuration services.

The Semantic Web will provide the conceptual infrastructure to allow new forms of business application integration. This paper outlines our approach for integrating Web-based sales systems for highly complex customizable products and services (configuration systems) making use of descriptive representation formalisms of the Semantic Web. The evolving trend towards highly specialized solution providers cooperatively offering configurable products and services to their customers requires the extension of current (standalone) configuration technology with capabilities of knowledge sharing and distributed configuration problem solving. On the one hand, a standardized representation language is needed in order to tackle the challenges imposed by heterogeneous representation formalisms of state-of-the-art configuration environments (e.g. description logic or predicate logic based configurators), on the other hand it is important to integrate the development and maintenance of configuration systems into industrial software development processes. We show how to support both goals by demonstrating the applicability of the Unified Modeling Language (UML) for configuration knowledge acquisition and by providing a set of rules for transforming UML models into configuration knowledge bases specified by languages such as OIL or DAML+OIL which represent the foundation for potential future description standards for Web services.

The trend towards highly specialized solution providers cooperatively offering configurable products and services to their customers requires the extension of current (standalone) configuration technology with capabilities of knowledge sharing and distributed configuration problem solving. On the one hand, a standardized representation language is needed in order to tackle the challenges imposed by heterogeneous representation formalisms of state-of-the-art configuration environments (e.g. description logic or predicate logic based configurators), on the other hand it is important to integrate the development and maintenance of configuration systems into industrial software development processes. We show how to support both goals by demonstrating the applicability of the Unified Modeling Language (UML) for configuration knowledge acquisition and by providing a set of rules for transforming UML models into configuration knowledge bases specified by languages such as OIL or DAML+OIL which represent the foundation for the description of configuration Web services.