The Business Process Execution Language for Web Services (BPEL) is the standard for implementing orchestrated business processes designed but not limited to, as web services. BPEL is a powerful language but lacks a widely accepted formal semantics, and this makes it difficult to formally validate the correct execution of BPEL implementations. In the other hand, process algebras have proved thei...

Business Process Execution Language for Web Services (BPEL) is an XML-based language used to define business process and workflow logic. While its original purpose was to provide a method of linking several disparate business applications, we have found that BPEL provides several features and advantages that lend it to incorporation in a clinical decision support (CDS) rule engine.

We present an extension of a Petri net semantics for the Web Service Business Execution Language (WS-BPEL). This extension covers the novel activities and constructs introduced by the recent WS-BPEL 2.0 specification. Furthermore, we simplify several aspects of the Petri net semantics to allow for more compact models suited for computer-aided verification.

The suitability of the BPEL workflow description language for the dynamic composition of Web services representing computational algebra systems is investigated. The prototype implementation of the system for dynamic generation of BPEL workflows and two examples demonstrating the benefits of our approach are described. One of important aspects of the design is that the composition is achieved u...