Ulrich Küster

DIANE: an integrated approach to automated service discovery, matchmaking and composition

Automated matching of semantic service descriptions is the key to automatic service discovery and binding. But when trying to find a match for a certain request it may often happen, that the request cannot be serviced by a single offer but could be handled by combining existing offers. In this case automatic service composition is needed. Although automatic composition is an active field of research it is mainly viewed as a planning problem and treated separatedly from service discovery. In this paper we argue that an integrated approach to the problem is better than seperating these issues as is usually done. We propose an approach that integrates service composition into service discovery and matchmaking to match service requests that ask for multiple connected effects, discuss general issues involved in describing and matching such services and present an efficient algorithm implementing our ideas.

DIANE: A Matchmaking-Centered Framework for Automated Service Discovery, Composition, Binding, and Invocation on the Web

Service-oriented computing will allow for the automatic discovery, composition, binding, and invocation of Web services. The single most important component of this goal is appropriate matchmaking. This paper presents a service-description language and its associated matchmaking algorithms. Together they precisely capture requester preferences through fuzzy sets, express and use instance information for matchmaking, and deal efficiently with multiple effects. The approach described here has been extensively evaluated both in experiments and in the 2006 Semantic Web Services Challenge.

Evaluation of Semantic Service Discovery—A Survey and Directions for Future Research

In recent years a huge amount of effort, and money has been invested in the area of semantic service discovery and presented approaches have become more sophisticated and mature. Nevertheless surprisingly little effort is being put into the evaluation of these approaches. We argue that the lack of established and theoretically well-founded methodologies and test beds for comparative evaluation of semantic service discovery is a major blocker of the advancement of the field. To lay the ground for a comprehensive treatment of this problem we discuss the applicability of well-known evaluation methodologies from information retrieval and provide an exhaustive survey of the current evaluation approaches.

TOWARDS STANDARD TEST COLLECTIONS FOR THE EMPIRICAL EVALUATION OF SEMANTIC WEB SERVICE APPROACHES

Semantic web services have received a significant amount of attention in the last years and many frameworks, algorithms and tools leveraging them have been proposed. Nevertheless surprisingly little effort has been put into the evaluation of the approaches so far. The main blocker of thorough evaluations is the lack of large and diverse test collections of semantic web services. In this paper we analyze requirements on such collections and shortcomings of the state-of-the-art in this respect. Our contribution to overcoming those shortcomings is OPOSSum, a portal to support the community to build the necessary standard semantic web service test collections in a collaborative way. We discuss how existing test collections have been integrated with OPOSSum, showcase the benefits of OPOSSum by an illustrative use case and outline next steps towards better standard test collections of semantic web services.

OPOSSum - An Online Portal to Collect and Share SWS Descriptions

Semantic web services have received a significant amount of research attention in the last years but too little effort has been put into the evaluation of the approaches so far. The main blocker of thorough evaluations is the lack of large and diverse test collections for semantic web services. In this demo we present a portal designed to help working towards common test collections by making it easy to collect, search for, and compare semantic service descriptions across various formalisms.

Measures for benchmarking semantic web service matchmaking correctness

Semantic Web Services (SWS) promise to take service oriented computing to a new level by allowing to semi-automate time-consuming programming tasks. At the core of SWS are solutions to the problem of SWS matchmaking, i.e., the problem of filtering and ranking a set of services with respect to a service query. Comparative evaluations of different approaches to this problem form the base for future progress in this area. Reliable evaluations require informed choices of evaluation measures and parameters. This paper establishes a solid foundation for such choices by providing a systematic discussion of the characteristics and behavior of various retrieval correctness measures in theory and through experimentation.

Supporting Dynamics in Service Descriptions - The Key to Automatic Service Usage

In realistic settings, service descriptions will never be precise reflections of the services really offered. An online seller of notebooks, for instance, will most certainly not describe each and every notebook offered in his service description. This imprecision causes poor quality in discovery results. A matcher will be able to find potentially matching services but can give no guarantees that the concrete service needed will really be provided. To alleviate this problem, a contract agreement phase between service provider and requester following the discovery has been suggested in the literature. In this paper, we present an approach to the automation of this contracting. At the heart of our solution is the possibility to extend service descriptions with dynamically changing information and to provide several means tailored to the abilities of the service provider to obtain this information at discovery time.

Relevance Judgments for Web Services Retrieval - A Methodology and Test Collection for SWS Discovery Evaluation

Semantic web services (SWS) promise to take service oriented computing to a new level by allowing to automatically locate and use functionality exposed as web services. At the core of SWS are solutions to the problem of SWS discovery, i.e., the problem of comparing semantic goal descriptions with semantic offer descriptions to determine services relevant to a given request. A plethora of different approaches to this problem have been proposed, but their comparative evaluation is challenging.While the evaluation setups from the information retrieval (IR) community provided a natural starting point to SWS discovery evaluation, the applicability of their assumptions have not been sufficiently discussed so far. This paper discusses the differences between traditional IR and SWS discovery and the resulting fundamental problems. It proposes a methodology and experimental setup for SWS discovery evaluation that addresses these problems. An initial realistic service test collection is presented and issues related to the central notion of relevance in the context of service discovery are examined. In particular the consistency of relevance judgments using three different relevance scales is experimentally investigated and the consequences on the evaluation methodology are discussed.

Dynamic binding for BPEL processes: a lightweight approach to integrate semantics into web services

The area of service oriented computing stretches between two extremes: On the one hand industry has pushed a whole stack of WS-* standards and tools to support the integration of distributed services into business applications. These standards are used in production environments and are applied successfully, e.g. in the area of enterprise application integration. However, the expensive and labor intensive task of putting together services and maintaining and administering the composed applications has to be done manually. In contrast, academia is busily working on numerous efforts leveraging ontology based semantics and various AI planning techniques to automate these tasks. Yet, up to now the developed technologies have rarely if ever been applied in industry. In our opinion, this has two main reasons: there is high cost involved in creating the necessary comprehensive ontologies and businesses are reluctant to trust semantic technologies. In this paper we bring together the extremes in order to combine their strengths.We show how to flexibly integrate advanced semantic service discovery, composition and invocation technology into manually created standard BPEL processes. Our approach leaves it to the discretion of the developer to flexibly choose an appropriate degree of automation for the process at hand and thus offers him complete control over the usage of semantic technology.

On the Empirical Evaluation of Semantic Web Service Approaches: Towards Common SWS Test Collections

Semantic web services have received a significant amount of attention in the last years and many frameworks, algorithms and tools leveraging them have been proposed. Nevertheless surprisingly little effort has been put into the evaluation of the approaches so far. The main blocker of thorough evaluations is the lack of large and diverse test collections of semantic web services. In this paper we analyze requirements on such collections and shortcomings of the state of the art in this respect. Our contribution to overcoming those shortcomings is OPOSSum, a portal to support the community to build the necessary standard semantic web service test collections in a collaborative way.