Proactively Composing Web Services as Tasks by Semantic Web Agents

Abstract

The chapter presents the framework for agent-enabled dynamic composition of Semantic Web Services. The approach and the framework have been developed in several research and development projects by ISRG and IOG. The core of the methodology is the new understanding of a Semantic Web Service as a capability of an intelligent software agent supplied with the proper ontological description. It is demonstrated how diverse Web Services may be composed and mediated by dynamic coalitions of software agents collaboratively performing tasks for service requestors. Middle Agent Layer is introduced to conduct the transformation of a WebSemantic Web Services are the emerging technology promising to become one of the future key enablers of the Semantic Web. There are strong prerequisites that, being self-described and selfcontained modular active components, Web services will appear to be the key elements in assembling intelligent software infrastructures in the near future.There is the emerging consensus that the ultimate challenge is to make Semantic Web Services automatically tradable and usable by artificial agents in their rational, proactive interoperation on the next generation of the Web. It may be solved by creating frameworks, standards, and software for automatic Web service discovery, execution, composition, interoperation and monitoring . Personal opinion of the authors is that the list should be extended by the means making services the subject of automated negotiation and trade. It is also important for future service enabled Semantic Web infrastructures to cope with business rules 3 , the notions and mechanisms of reputation and trust with respect to services and service providing agents, dynamic character, flexibility, reconfigurability of partial plans (Ermolayev and Plaksin, 2002), workflows, and modeled business processes.Current industry landscape provides only initial and very partial solutions to the ultimate problem. usage. This remark seems to be rational as far as we pay either the salary to the office manager or a fee to a travel agent, who make arrangements for us in a human-business environment.Moreover, it is not in the eye of the service requestor, but the agent performing 'BookRoundtrip' service will realize according to the service markup or the Partial Local Plan (PLP) in our terminology (Ermolayev et al., 2001;Ermolayev et al., 2005) that the requested process (OWL-S, 2003) or the task in our terminology (Ermolayev et al., 2001;Ermolayev et al., 2005) is composite and will require cooperation with at least air companies' service providing agents and hotel booking service providing agents. These independent actors will evidently also intend to increase their own utilities by requesting fees for their services.The chapter first provides the overview of the basic notions, approaches and architectural solutions with respect to agent paradigm, WWW and the Semantic Web, Semantic Web Services. Detailed discussion of the popular travel planning scenario helps to claim that fullscale Web Se...

Algebraic Structure of Web Services

“…Hence, (p + f + h) * would give all iterations where either the flight, the hotel or the overall planning would be executed first and then the others. The result of this iteration is skip (the element Δ) or p, f, h, pf, ph, fp, fh, hp, hf, pfh, phf, fph, fhp, hpf, hfp, ... 5 or any other combination of these 5 Due to readability we leave ; implicit.…”

“…A composition can be achieved agent-based (as in [17,5]), based on interaction protocols [25], symbolic transition systems [23] or based on some kind of logic [8]. Very often process algebras or Petri nets are used, too.…”

Incorporating structural improvement into resource allocation for business process execution planning

“… investigated resource planning for service oriented workflows. Also, in the area of Web service composition, several approaches have been proposed to deal with the planning problem based on artificial intelligence planning methods in a bottom–up manner. These works are based on an assumption that the given process structure is optimal, and resource allocation is based on this fixed structure.…”