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In the era of Global Services, Service Oriented Architecture (SOA) has been gaining momentum for building Web-based information systems. Service composition is one of the key objectives for adopting SOA. Unfortunately, Web services are not always exactly compatible and it is a non-trivial task to address the mismatches between them. To this end, an approach based on mediator patterns is proposed to develop mediators for reconciling protocol mismatches of partially compatible services and mediating them together. A heuristic technique is developed for identifying protocol mismatches and selecting appropriate patterns. The main steps of the reconciliation approach are presented., The work is partially supported by the MIT Sloan China Management Education Project.

In the era of Global Services, Service Oriented Architecture (SOA) has been gaining momentum for building Web-based information systems. Service composition is one of the key objectives for adopting SOA. Unfortunately, Web services are not always exactly compatible and it is a non-trivial task to address the mismatches between them. To this end, an approach based on mediator patterns is proposed to develop mediators for reconciling protocol mismatches of partially compatible services and mediating them together. A heuristic technique is developed for identifying protocol mismatches and selecting appropriate patterns. The main steps of the reconciliation approach are presented., The work is partially supported by the MIT Sloan China Management Education Project.

Service Oriented Computing (SOC) is a popular computing paradigm for the development of distributed Web applications. Service composition, a key element of SOC, is severely hampered by various types of semantic heterogeneity among the services. In this paper, we address the various semantic differences from the context perspective and use a lightweight ontology to describe the concepts and their specializations. Atomic conversions between the contexts are implemented using XPath functions and external services. The correspondences between the syntactic service descriptions and the semantic concepts are established using a flexible, standard-compliant mechanism. Given the naive BPEL composition ignoring semantic differences, our reconciliation approach can automatically determine and reconcile the semantic differences. The mediated BPEL composition incorporates necessary conversions to convert the data exchanged between different services. Our solution has the desirable properties (e.g., adaptability, extensibility and scalability) and can significantly alleviate the reconciliation efforts for Web services composition., This work was partially supported by the MIT Sloan China Management Education Project and grants from the National Natural Science Foundation of China (No. 60674080 and No. 60704027) and the National High-Tech R&D (863) Plan of China (No. 2007AA04Z150).

The potential benefits of Web services composition heavily rely on semantic interoperability, i.e., the ability to exchange data meaningfully amongst Web services. Context heterogeneity, which refers to different implicit assumptions about interpreting the exchanged data, hampers the automatic composition of Web services. However, existing initiatives of semantic Web services (SWSs) often ignore context heterogeneity. In this paper, we introduce an approach to address this issue. The contexts of the involved Web services are defined in a lightweight ontology and their WSDL descriptions are annotated by an extension of a W3C standard, i.e., semantic annotation for WSDL and XML schema (SAWSDL). The composition of Web services is described using BPEL specification. Given a BPEL file that ignores context heterogeneity, the approach automatically detects all context differences among the involved services, and reconciles them by producing a mediated BPEL file that incorporates necessary conversions using Xpath functions and/or Web services., MIT-China Management Education Project, National Natural Science Foundation (China) (No. 60674080) (No. 60704027), National High-Tech R&D (863) Plan of China (No. 2007AA04Z150)