Web service compositions are gaining attention to develop complex web systems by combination of existing services. Thus, there are many works that leverage the advantages of this approach. However, there are only few works that use web service compositions to manage distributed resources. In this paper, we then present a formal model that combines orchestrations written in BPEL with distributed...

As the capability of an individual Web service is limited, it’s necessary to create new functionalities with existing Web services. Web services composition is the ability to create a new value-added service by incorporating some existing web services together. A model based colored Petri net (CPN) to provide semantic support for web service composition is proposed. The basic composite construc...

In a Cloud-computing environment, consumers, brokers, and service providers interact to achieve their individual purposes. In this regard, service providers offer a pool of resources wrapped as web services, which should be composed by broker agents to provide a single virtualized service to Cloud consumers. In this study, an agent-based test bed for simulating Cloudcomputing environments is de...

The Web Service Business Process Execution Language (WSBPEL) is the de facto standard for describing workflow-like compositions of Web services, so-called Web service orchestrations. In this paper an ontology for executable BPEL processes is presented, which reflects both the natural language description and the syntax given in the specification. The ontology makes BPEL process models accessibl...

We study open nets as Petri net models of web services, with a link to the practically relevant language WS-BPEL. For those nets, we investigate the problem of serviceableness which we consider as fundamental as the successful notion of soundness for workflow nets, i.e. Petri net models of business processes and workflows. While we could give algorithmic solutions to the serviceableness problem...

Current Web service choreography proposals, such as WSCI and BPEL, provide notations for describing the message flows in Web service collaborations. The kernel of WSCI consists of simple communication primitives that may be combined using control-flow constructs expressing sequence, branching, parallelism, synchronization, etc. Many efforts have been made on functional formalization and propert...

BPEL has emerged as the de-facto standard for implementing processes based on web services while formal languages like Petri nets have been proposed as an “academic response” allowing for all kinds of analysis. Although languages such as BPEL and Petri nets can be used to describe service flows, they both tend to “overspecify” the process and this does not fit well with the autonomous nature of...

The Business Process Execution Language (BPEL) is now a de facto standard for specifying and executing business process for web service composition and orchestration. As more and more web services are composed using BPEL, tuning these compositions and gain better performance becomes increasingly important. This paper presents our approach for optimizing the BPEL process and introduces OptBPEL, ...

The Business Process Execution Language (BPEL) is a widely recognized executable language supporting the specification of process-oriented service compositions. However, the language is limited in addressing variable requirements in the description of business processes. We propose to construct variable and maintainable Web services compositions with VxBPEL, an extension to BPEL we developed to...