Many challenges of bringing communicating multiagent systems to the Web require ontologies. The integration of agent technology and ontologies could significantly affect the use of Web services and the ability to extend programs to perform tasks for users more efficiently and with less human intervention.

Although description logic systems can adequately be used for representing and reasoning about incomplete information (e.g., for John we know he is French or Italian), in practical applications it can be assumed that (only) for some tasks the expressivity of description logics really comes into play whereas for building complete applications, it is often necessary to effectively solve instance retrieval problems with respect to largely deterministic knowledge. In this paper we present and analyze the main results we have found about how to contribute to this kind of scalability problem. We assume familiarity with description logics in general and tableau provers in particular.

malli @ cn.ibm.com Abstract. Reasoning on OWL ontologies is known to be intractable in the worst-case, which is a serious problem because in practice, most OWL ontologies have large Aboxes, i.e., numerous assertions about individuals and their relations. We propose a technique that uses a summary of the ontology (summary Abox) to reduce reasoning to a small subset of the original Abox, and prove that our techniques are sound and complete. We demonstrate the scalability of this technique for consistency detection in 4 ontologies, the largest of which has 6.5 million role assertions. 1

Background: The development of e-Science presents a major set of opportunities and challenges for the future progress of biological and life scientific research. Major new tools are required and corresponding demands are placed on the high-throughput data generated and used in these processes. Nowhere is the demand greater than in the semantic integration of these data. Semantic Web tools and technologies afford the chance to achieve this semantic integration. Since pathway knowledge is central to much of the scientific research today it is a good test-bed for semantic integration. Within the context of biological pathways, the BioPAX initiative, part of a broader movement towards the standardization and integration of life science databases, forms a necessary prerequisite for its successful application of e-Science in health care and life science research. This paper examines whether BioPAX, an effort to overcome the barrier of disparate and heterogeneous pathway data sources, addresses the needs of e-Science. Results: We demonstrate how BioPAX pathway data can be used to ask and answer some useful biological questions. We find that BioPAX comes close to meeting a broad range of e-Science needs, but certain semantic weaknesses mean that these goals are missed. We make a series of

Abstract. The success of the Web services technology has brought topics as software reuse and discovery once again on the agenda of software engineers. While there are several efforts towards automating Web service discovery and composition, many developers still search for services via online Web service repositories and then combine them manually. However, from our analysis of these repositories, it yields that, unlike traditional software libraries, they rely on little metadata to support service discovery. We believe that the major cause is the difficulty of automatically deriving metadata that would describe rapidly changing Web service collections. In this paper, we discuss the major shortcomings of state of the art Web service repositories and, as a solution, we report on ongoing work and ideas on how to use techniques developed in the context of the Semantic Web (ontology learning, mapping, metadata based presentation) to improve the current situation. 1

Abstract. This work is motivated by experiences in the course of developing an ontology-based application within a real-world setting. We found out that current benchmarks are not well suited to provide helpful hints for users who seek for an appropriate reasoning system able to deal with expressive terminological descriptions, large volumes of assertional data, and frequent updates in a sound and complete way. This paper tries to provide some insights into currently available reasoning approaches and aims at identifying requirements to make future benchmarks more useful for application developers. 1 On Benchmarking OWL Reasoners Having sufficiently exhaustive knowledge about the influence of the underlying reasoning approach on the practical tractability of a particular ontology is of fundamental importance when selecting an inference engine for a real-world application. By real-world we mean an ontology-based application with an expressivity at least beyond ALC, containing more than thousands of individuals,

Abstract. The DIG Interface provides an implementation-neutral mechanism for accessing Description Logic reasoner functionality. At a high level the interface consists of XML messages sent to the reasoner over HTTP connections, with the reasoner responding as appropriate. Key changes in the current version (DIG 2.0) include support for OWL 1.1 and well-defined mechanisms for extensions to the basic interface. 1

Abstract. We address the problem of answering Web ontology queries efficiently. An ontology is formalized as a Deductive Ontology Base (DOB), a deductive database that comprises the ontology’s inference axioms and facts, and we present a cost-based query optimization technique for DOB. A hybrid cost model is proposed to estimate the cost and cardinality of basic and inferred facts. Cardinality and cost of inferred facts are estimated using an adaptive sampling technique, while techniques of traditional relational cost models are used for estimating the cost of basic facts and conjunctive ontology queries. Finally, we implement a dynamic-programming optimization algorithm to identify query evaluation plans that minimize the number of intermediate inferred facts. We modeled a subset of the Web ontology language OWL Lite as a DOB, and performed an experimental study to analyze the predictive capacity of our cost model and the benefits of the query optimization technique. Our study has been conducted over synthetic and real-world OWL ontologies, and shows that the techniques are accurate and improve query performance. 1

Abstract. There are few successful applications of automated reasoning over OWL-formalised bio-ontologies, and requirements are often unclearly formulated. Of what is available, usage and prospective scenarios of automated reasoning is often different from the straightforward classification and satisfiability. We list nine types of scenarios and specify the requirements in more detail. Several of these requirements are already possible in practice or at least in theory, others are in need of further research, in particular regarding the linking of the OWL ontology to data, reasoning over roles, and dynamically linking modular ontologies. 1

Abstract. The DIG Interface provides an implementation-neutral mechanism for accessing Description Logic reasoner functionality. At a high level the interface can be realised as XML messages sent to the reasoner over HTTP connections, with the reasoner responding as appropriate. Key changes in the current version (DIG 2.0) include support for OWL 1.1 and well-defined mechanisms for extensions to the basic interface. 1