Web processes are the next generation workflows created using Web services. This paper addresses research issues in creating a framework for configuring and executing dynamic Web processes. The configuration module uses Semantic Web service discovery, integer linear programming and logic based constraint satisfaction to configure the process, based on quantitative and non-quantitative process constraints. Semantic representation of Web services and process constraints are used to achieve dynamic configuration. An execution environment is presented, which can handle heterogeneities at the protocol and data level by using proxies with data and protocol mediation capabilities. In cases of Web service failures, we present an approach to reconfigure the process at run-time, without violating the process constraints. Empirical testing of the execution environment is performed to compare deployment-time and run-time binding. 1.

We present methods for optimally adapting Web processes to exogenous events while preserving inter-service constraints that necessitate coordination. For example, in a supply chain process, orders placed by a manufacturer may get delayed in arriving. In response to this event, the manufacturer has the choice of either waiting out the delay or changing the supplier. Additionally, there may be compatibility constraints between the different orders, thereby introducing the problem of coordination between them if the manufacturer chooses to change the suppliers. We focus on formulating the decision making models of the managers, who must adapt to external events while satisfying the coordination constraints, using Markov decision processes. Our methods range from being centralized and globally optimal in their adaptation but not scalable, to decentralized that is suboptimal but scalable to multiple managers. We also develop a hybrid approach that improves on the performance of the decentralized approach with a minimal loss of optimality. 1

We present a goal-driven approach to model a choreographer for realizing composite Web services. In this framework, the users start with an abstract, and possibly incomplete functional specification of a desired goal service. This specification is used to compose a choreographer that allows communication between the client and the set of available component services, and is functionally equivalent to the goal service. However, if such a composition cannot be realized, the proposed approach identifies the cause(s) for the failure of composition. This information can be used by the user to minimally reformulate the goal to reduce the ‘gap between the desired functionality. The process can be iterated until a feasible composition is realized or the user decides to abort. The approach ensures that (i) a choreographer, if one is produced by our composition algorithm, in fact realizes the user-specified goal functionality; and (ii) the algorithm is guaranteed to find a composition that meets the user needs as captured in the goal specifications (whenever such a composition exists).

We propose a specification-driven approach to Web service composition. The proposed framework allows users to start with a high-level, possibly incomplete specification of a desired (goal) service that is to be realized using a subset of the available component services. These services are represented by the system using transition systems augmented with guards over variables with infinite domains and are used to determine a strategy for their composition that would realize the goal service. In the event that the goal service cannot be realized using the available services, the system identifies the cause(s) for such failure which can then be used by the developer to reformulate the goal specification. Thus, the system supports Web service composition through iterative refinement of the functional specifications. We present a prototype implementation in tabled-logic programming environment that illustrates the key features of the proposed approach.

Development of sound approaches and software tools for specification, assembly, and deployment of composite Web services from independently developed components promises to enhance collaborative software design and reuse. In this context, the proposed research introduces a new incremental approach to service composition, MoSCoE (Modeling Web Service Composition and Execution), based on the three steps of abstraction, composition and refinement. Abstraction refers to the high-level description of the service desired (goal) by the user, which drives the identification of an appropriate composition strategy. In the event that such a composition is not realizable, MoSCoE guides the user through successive refinements of the specification towards a realizable goal service that meets the user requirements.

Abstract—Web services composition has been an active research area over the last few years. However, the technology is still not mature yet and several research issues need to be addressed. In this paper, we describe the design of CCAP, a system that provides tools for adaptive service composition and provisioning. We introduce a composition model where service context and exceptions are configurable to accommodate needs of different users. This allows for reusability of a service in different contexts and achieves a level of adaptiveness and contextualization without recoding and recompiling of the overall composed services. The execution semantics of the adaptive composite service is provided by an event-driven model. This execution model is based on Linda Tuple Spaces and supports real-time and asynchronous communication between services. Three core services, coordination service, context service, and event service, are implemented to automatically schedule and execute the component services, and adapt to user configured exceptions and contexts at run time. The proposed system provides an efficient and flexible support for specifying, deploying, and accessing adaptive composite services. We demonstrate the benefits of our system by conducting usability and performance studies. Index Terms—Web service, service composition, service-oriented architecture, exception handling, event-based service execution. Ç 1

Thanks to recent advances, AI Planning has become the underlying technique for several applications. Figuring prominently among these is automated Web Service Composition (WSC) at the “capability ” level, where services are described in terms of preconditions and effects over ontological concepts. A key issue in addressing WSC as planning is that ontologies are not only formal vocabularies; they also axiomatize the possible relationships between concepts. Such axioms correspond to what has been termed “integrity constraints ” in the actions and change literature, and applying a web service is essentially a belief update operation. The reasoning required for belief update is known to be harder than reasoning in the ontology itself. The support for belief update is severely limited in current planning tools. Our first contribution consists in identifying an interesting special case of WSC which is both significant and more tractable. The special case, which we term forward effects, is characterized by the fact that every ramification of a web service application involves at least one new constant generated as output by the web service. We show that, in this setting, the reasoning required for belief update simplifies to standard reasoning in the ontology itself. This relates to, and extends,

For comprehensive software lifecycle processes, a trichotomy continues to subsist between the software development processes, enterprise IT processes, and the software runtime environment. Currently, integrating software lifecycle processes requires substantial effort, and the information needed for the execution of (semi-)automated software lifecycle workflows is not readily accessible and is typically scattered across semantically heterogeneous sources. Consequently, an interrupted flow of information ensues between the development/maintenance phases and operational phases in the software lifecycle, resulting in ignorance, inefficiencies, and suboptimal product quality and support levels. Furthermore, today’s abstract IT (e.g., ITIL) and software processes are often derived into concrete processes and workflows manually, causing errors, extensive effort, and limiting widespread adoption of best practices. This paper describes an approach for improving information flow throughout the software lifecycle via the (semi-)automated realization of abstract software lifecycle processes and workflows in combination with Semantic Web technologies. 1

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Automated web service composition is one of the major promises of serviceoriented architecture, where services can be discovered and composed dynamically and automatically. To investigate the methods for composite web service construction, we conducted an experiment on creating useful composite web services from real existing web services where semantic annotations are not available. The empirical study reveals the difficulties and research challenges in the discovery, invocation, and composition of web services. The automation of web service composition requires the inputs from both services providers and service consumers. Service providers need to develop high quality services in a disciplined and collaborative way, and service consumers need to be equipped with tools providing helps such as service discovery and matching.