BPEL Extension Research Articles

BPEL Extensions to User-Interactive Service Delivery

Web Services Business Process Execution Language) is adopted industrial-wide as the de facto service composition standard. However, a BPEL composite service is typically treated as a fully automated service flow that orchestrates multiple web services and involves no user interactions-a desirable feature for service delivery, and is presently not included in the BPEL standard. In this work, we propose an extension to BPEL to infuse user interactions into composite services along three dimensions: (1) to develop two BPEL extension activities to describe the inner workings of user interactions in BPEL service and the rendering of service user interfaces; (2) to provide a wizard-style mechanism to guide the user to interact with the service flow in accordance with the sequence of service execution; and (3) to devise a UI service communication protocol to facilitate secure cross-domain communication among UI services from various domains. An enhanced BPEL engine with a service UI rendering engine has been accordingly developed.

Secure on-demand grid computing

In this paper, a novel approach for enabling Grid users to autonomously install and use custom software on demand using an image creation station is presented, while at the same time offering new security mechanisms to protect both software and data from other Grid users and external attackers. An automated dynamic firewalling mechanism enables both virtual organization and user-based network security setups. Furthermore, the Grid environment is partitioned into several zones to protect local cluster resources from compromised Grid middleware. To enable the secure integration of this Grid environment into existing business processes, an extension of BPEL is presented which allows the execution of GSI secured Grid services in combination with existing business web services. The workflow engine transparently handles proxy certificate creation and monitors proxy certificate lifetime. An implementation based on the Globus Toolkit 4, the Sun Grid Engine and the ActiveBPEL Engine is presented. A performance evaluation of the critical components of the new Grid setup is provided.