Automatic Composition and Invocation of Semantic Web Services

eb Services are viewed as a new paradigm for building distributed web applications. The W3C de�nes web services as a programmatic interface that enables communica- tion among applications. OWL-S (earlier known as DAML-S) is an initiative that aims to describe web services using semantic web languages like RDF, RDFS and OWL. The motive behind adding semantics is to enable automatic discovery, compo- sition, invocation and execution monitoring. In this thesis, we look at the problem of web service composition - synthesizing complex tasks from a set of atomic tasks. We look at how a service description can be transformed into planning oper- ators. We present a planner that uses a backward-chaining algorithm for the task of composition. We also discuss an algorithm for automatic invocation. The automatic invocation algorithm takes the plan generated by the planner and determines data re- quired for invocation using queries. Finally, we discuss the architecture of our agent, which is capable of interacting with web services solely based on service descriptions.