The task of verifying the compatibility between interacting web services has traditionally been limited to checking the compatibility of the interaction protocol in terms of message sequences and the type of data being exchanged. Since web services are developed largely in an uncoordinated way, different services often use independently developed ontologies for the same domain instead of adhering to a single ontology as standard. In this work we investigate the approaches that can be taken by the server to verify the possibility to reach a state with semantically inconsistent results during the execution of a protocol with a client, if the client ontology is published. Often database is used to store the actual data along with the ontologies instead of storing the actual data as a part of the ontology description. It is important to observe that at the current state of the database the semantic conflict state may not be reached even if the verification done by the server indicates the possibility of reaching a conflict state. A relational algebra based decision procedure is also developed to incorporate the current state of the client and the server databases in the overall verification procedure.
Web service is an important technology to implement business to business e-commerce interaction. The first step toward this interaction is the discovery of other services. In this paper we claim that discovery of Web services should be based on the semantic match between service advertisement and service request. We show how service capabilities are presented by the OWL-S profile, an OWL based language for service description. In particular, we describe the design and implementation of a service matchmaking agent which uses an OWL-S based ontology and a OWL reasoner to compare ontology based service descriptions. The service discovery based on semantic description plays an important role in the process of Web service composition. Traditional approaches to modeling semantic similarity between Web services compute subsume relationship for function parameters in service profiles within a single ontology. In this paper, we introduce a new graph theoretic framework based on bipartite graph matching for finding the best correspondences among function parameters belonging to advertisement and request. On computing semantic similarity between a pair of function parameters, we present a novel similarity function determining similar entity, which relaxes the requirement of a single ontology and accounts for the different ontology specifications The growing number of web services advocates distributed discovery infrastructures which are semantics-enabled and support quality of service (QoS). In this paper, we introduce a novel approach for semantic discovery of web services in P2P-based registries taking into account QoS characteristics. We distribute (semantic) service advertisements among available registries such that it is possible to quickly identify the repositories containing the best probable matching services. Additionally, we represent the information relevant for the discovery process using Bloom filters and pre-computed matching information such that search efforts are minimized when querying for services with a certain functional QoS profile. Query results can be ranked and users can provide feedbacks on the actual QoS provided by a service. To evaluate the credibility of these user reports when predicting service quality, we include a robust trust and reputation management mechanism. This paper describes a framework for ontology-based flexible discovery of Semantic Web services. The proposed approach relies on user-supplied, context-specific mappings from an user ontology to relevant domain ontologies used to specify Web services. We show how a user's query for a Web service that meets certain selection criteria can be transformed into queries that can be processed by a matchmaking engine that is aware of the relevant domain ontologies and Web services. We also describe how user-specified preferences for Web services in terms of non-functional requirements (e.g., QoS) can be incorporated into the Web service discovery mechanism to generate a partially ordered list of services that meet user-specified functional requirements. We present an approach to hybrid semantic Web service matching that complements logic based reasoning with approximate matching based on syntactic IR based similarity computations. The hybrid matchmaker, called OWLS-MX, applies this approach to services and requests specified in OWL-S. Experimental results of measuring performance and scalability of different variants of OWLS-MX show that under certain constraints logic based only approaches to OWL-S service I O matching can be significantly outperformed by hybrid ones.