What is Simple Object Access Protocol

In the Service-Driven Computing paradigm, applications are typically built by composing a set of Web services. Web service composition facilitates rapid development of applications via service reuse and enables the creation of complex services from simpler application services. Research efforts in the area of Web service composition are concerned mainly with two challenges, namely automated service synthesis and verification of the composed Web services. This chapter presents a framework for Web service composition based on semantic specification through OWL-S to establish an ontological agent for automating Web service composition. The semantic description serves to define the planning domain for the agent to automate the composition procedure. A Petri nets model is applied to build a formal representation of the structure and behavior of the service. Finally, AND-OR graph methodology is used to represent the dependences among Web services to select between alternatives based on Quality of Service.