The Web Service Execution Environment

Computer science is on the edge of an important new period of abstraction. A generation ago we learned to abstract from hardware and currently we learn to abstract from software in terms of Service Oriented Architectures (SOA). A Service Oriented Architecture is essentially a collection of services. However, we believe that these SOAs will not scale without significant mechanization of service discovery, service adaptation, service negotiation, service composition, service invocation, and service monitoring, as well as data-, protocol-, and process-mediation. We envisage the future of applied computer science in terms of service-oriented architectures which is empowered by adding semantics as a means of dealing with heterogeneity and mechanization of service usage. This approach is called Semantically Enabled Service-oriented Architectures, or SESA for short. In this chapter, we give an introduction to SESA and Web Service Execution Environment (WSMX) as its most prominent implementation. First, we are motivating the SESA approach, followed by an analysis of SESA vision, and governing principles. Special attention is paid to the notion of Execution Semantics, basic SESA services and WSMX. The elaboration is followed by a larger example demonstrating steps needed to achieve a WSMO goal.