Web service composition: A survey of techniques and tools

Web services are a consolidated reality of the modern Web with tremendous, increasing impact on everyday computing tasks. They turned the Web into the largest, most accepted, and most vivid distributed computing platform ever. Yet, the use and integration of Web services into composite services or applications, which is a highly sensible and conceptually non-trivial task, is still not unleashing its full magnitude of power. A consolidated analysis framework that advances the fundamental understanding of Web service composition building blocks in terms of concepts, models, languages, productivity support techniques, and tools is required. This framework is necessary to enable effective exploration, understanding, assessing, comparing, and selecting service composition models, languages, techniques, platforms, and tools. This article establishes such a framework and reviews the state of the art in service composition from an unprecedented, holistic perspective

Repairing web service compositions based on planning graph

With the increasing acceptance of service-oriented computing, a growing area of study is the way to reuse the loosely coupled Web services, distributed throughout the Internet, to fulfill business goals in an automated fashion. When the goals cannot be satisfied by a single Web service, a chain of Web services can work together as a "composition" to satisfy the needs. The problem of finding composition plans to satisfy given requests is referred to as the Web service composition problem. In recent years, many studies have been done in this area, and various approaches have been proposed. However, most existing proposals endorse a static viewpoint over Web service composition; while in the real world, change is the rule rather than an exception. Web services may appear and disappear at any time in a non-predictable way. Therefore, valid composition plans may suddenly become invalid due to the environment changes in the business world. In this thesis, techniques to support reparation for an existing plan as a reaction to environment changes are proposed. Approaches of repair are compared to ones of re-planning, with particular attention to the time and quality of both approaches. It will be argued that the approach advocated in this thesis is a viable solution to improve the adaptation of automated Web service composition processes in the context of the real world

An adaptive service oriented architecture: Automatically solving interoperability problems.

Organizations desire to be able to easily cooperate with other companies and still be flexible. The IT infrastructure used by these companies should facilitate these wishes. Service-Oriented Architecture (SOA) and Autonomic Computing (AC) were introduced in order to realize such an infrastructure, however both have their shortcomings and do not fulfil these wishes. This dissertation addresses these shortcomings and presents an approach for incorporating (self-) adaptive behavior in (Web) services. A conceptual foundation of adaptation is provided and SOA is extended to incorporate adaptive behavior, called Adaptive Service Oriented Architecture (ASOA). To demonstrate our conceptual framework, we implement it to address a crucial aspect of distributed systems, namely interoperability. In particular, we study the situation of a service orchestrator adapting itself to evolving service providers.

SmartPM: automatic adaptation of dynamic processes at run-time

The research activity outlined in this thesis is devoted to define a general approach, a concrete architecture and a prototype Process Management System (PMS) for the automated adaptation of dynamic processes at run-time, on the basis of a declarative specification of process tasks and relying on well-established reasoning about actions and planning techniques. The purpose is to demonstrate that the combination of procedural and imperative models with declarative elements, along with the exploitation of techniques from the field of artificial intelligence (AI), such as Situation Calculus, IndiGolog and automated planning, can increase the ability of existing PMSs of supporting dynamic processes. To this end, a prototype PMS named SmartPM, which is specifically tailored for supporting collaborative work of process participants during pervasive scenarios, has been developed. The adaptation mechanism deployed on SmartPM is based on execution monitoring for detecting failures at run-time, which does not require the definition of the adaptation strategy in the process itself (as most of the current approaches do), and on automatic planning techniques for the synthesis of the recovery procedure