The Synthy Approach for End to End Web Services Composition: Planning with Decoupled Causal and Resource Reasoning

Abstract

Web services offer a unique opportunity to simplify applica-tion integration by defining common, web-based, platform-neutral, standards for publishing service descriptions to a registry, finding and invoking them – not necessarily by the same parties. Viewing software components as web services, the current solutions to web services composition based on business web services (using WSDL, BPEL, SOAP etc.) or semantic web services (using ontologies, goal-directed rea-soning etc.) are both piecemeal and insufficient for build-ing practical applications. Inspired by the work in AI plan-ning on decoupling causal (planning) and resource reasoning (scheduling), we introduced the first integrated work in com-posing web services end to end from specification to deploy-ment by synergistically combining the strengths of the cur-rent approaches. The solution is based on a novel two–staged composition approach that addresses the information model-ing aspects of web services, provides support for contextual information while composing services, employs efficient de-coupling of functional and non-functional requirements, and leads to improved scalability and failure handling. A pro-totype of the solution has been implemented in the Synthy service composition system and applied to a number of com-position scenarios from the telecom domain. The application of planning to web services has also brought new plan and planner usability-driven research issues to the fore for AI.