Planning Process Instances with Web Services

TL;DR: It is shown that planning technology really is necessary by giving an example of web service composition that cannot be solved with simpler t echnologies as could previously published examples and the basics of adapting planning to web service co mposition are described.

Abstract: Planning is an important approach to developing complex app lications composed of web services, based upon semantic annotations o f these services. Despite numerous publications in recent years, the problem s considered in the literature typically do not require planning as it has been w ell-defined in computer science. This could lead to confusion about which tech nologies are being designated, and raises the question of what whether plannin g is an appropriate technology for services. We describe the essential features of planning technology a nd note its advantages, which include the dynamic synthesis of processes and the lac k of need to verify the correctness of the message exchange. We show that planning technology really is necessary by givi n an example of web service composition that cannot be solved with simpler t echnologies as could previously published examples. We describe the basics of adapting planning to web service co mposition. We restrict its use to process instance synthesis in order to simp lify exploration of some fundamental issues. A major issue is that web services are us ually incompletely modeled. We illustrate this with a second example. We show so me additional semantic annotations of web services can be used to solve the pr oblems similar to the example when used in conjunction with re-planning.