QoS Aware Semantic Web Service Composition Approach Considering Pre/Postconditions

Web service composition is a topic bringing several issues to be resolved. Our work deals with the effectiveness and scalability of service composition. During composition we consider QoS and pre-/post-conditions of single services to create a composite service satisfying the user needs the best. Regarding pre-/post-conditions we propose an approach to fast determination of which services produce results expected by the user, i.e. the post-condition of which services implicates the desired condition defined in the user goal. This paper proposes also an approach to restriction on the service space which provided a dramatic improvement in terms of composition time.