Using ontologies for modeling context-aware services platforms

This paper discusses the suitability of using ontologies for modeling context-aware services platforms. It addresses the directions of research we are following in the WASP (Web Architectures for Services Platforms) project. For this purpose a simple scenario is considered

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

Contorsion: A Semantic XPath Processor

AbstractThis work describes the architecture of Contorsion, a semantic XPath processor that acts over an RDF mapping of XML. It contributes to a recent research trend that defines an XML-to-RDF mapping allowing XML documents interoperate at the semantic level. We use a model-mapping approach to represent instances of XML and XML Schema in RDF. This representation retains the node order, in contrast with the usual structure-mapping approach. The processor can be fed with an unlimited set of XML schemas and/or RDFS/OWL ontologies. The queries are resolved taking in consideration the structural and semantic connections descrived in the schemas and ontologies. Such behaviour, schema-awareness and semantic integration, can be useful for exploiting schema and ontology hierarchies in XPath queries

ODEval: a Tool for Evaluating RDF(S), DAML+OIL, and OWL Concept Taxonomies

Ontologies implemented in RDF(S), DAML+OIL, and OWL should be evaluated from the point of view of knowledge representation before using them in Semantic Web applications. Several language-dependent ontology validation tools and ontology platforms, such as OilEd with FaCT, can be used in order to evaluate RDF(S), DAML+OIL and OWL ontologies. This paper offers two main contributions. The first of these exams whether previous ontology tools detect knowledge representation problems in RDF(S), DAML+OIL, and OWL concept taxonomies. Indeed, such tools do not focus on detecting inconsistencies and redundancies in concept taxonomies. The second contribution is ODEval, a language-dependent tool for evaluating, from the point of view of knowledge representation, concept taxonomies in ontologies implemented in such languages. ODEval complements previous ontology tools when we want to evaluate RDF(S), DAML+OIL, and OWL concept taxonomie

PSPACE Reasoning for Graded Modal Logics

We present a PSPACE algorithm that decides satisfiability of the graded modal logic Gr(K_R)---a natural extension of propositional modal logic K_R by counting expressions---which plays an important role in the area of knowledge representation. The algorithm employs a tableaux approach and is the first known algorithm which meets the lower bound for the complexity of the problem. Thus, we exactly fix the complexity of the problem and refute an ExpTime-hardness conjecture. We extend the results to the logic Gr(K_(R \cap I)), which augments Gr(K_R) with inverse relations and intersection of accessibility relations. This establishes a kind of ``theoretical benchmark'' that all algorithmic approaches can be measured against

Open world reasoning in semantics-aware access control: A preliminary study

We address the relationships between theoretical foundations of Description Logics and practical applications of security-oriented Semantic Web techniques. We first describe the advantages of semantics-aware Access Control and review the state of the art; we also introduce the basics of Description Logics and the novel semantics they share. Then we translate the principle underlying the Little House Problem of DL into a real-world use case: by applying Open World Reasoning to the Knowledge Base modelling a Virtual Organization, we derive information not achievable with traditional Access Control methodologies. With this example, we also show that a general problem such as ontology mapping can take advantage of the enhanced semantics underlying OWL Lite and OWL DL to handle under-specified concepts

Situation Aware Cognitive Assistance in Smart Homes

Smart Homes (SH) have emerged as a realistically viable solution capable of providing technology-driven assistive living for the elderly and disabled. Nevertheless, it still remains a challenge to provide situation-aware cognitive assistance for those in need in their Activity of Daily Living (ADL). This paper introduces a systematic approach to providing situation-aware ADL assistances in a smart home environment. The approach makes use of semantic technologies for sensor data modeling, fusion and management, thus creating machine understandable and processable situational data. It exploits intelligent agents for interpreting and reasoning semantic situational (meta)data to enhance situation-aware decision support for cognitive assistance. We analyze the nature and issues of SH-based healthcare for cognitively deficient inhabitants. We discuss the ways in which semantic technologies enhance situation comprehension. We describe a cognitive agent for realizing high-level cognitive capabilities such as prediction and explanation. We outline the implementation of a prototype assistive system and illustrate the proposed approach through simulated and real-time ADL assistance scenarios in the context of situation aware assistive living