An Ad-Hoc Workflow System Architecture Based on Mobile Agents and Rule-Based Processing Jie Meng, Sumi Helal and Stanley Su Computer and Information Science and Engineering University of Florida, Gainesville, FL 32611 {jmeng,helal,sul}@cise.ufl.edu Abstract As e-commerce permeates the globe, hundreds of thousand of web-based services are being created and provided to end users and organizations. Even though these services are developed independently, they are nevertheless loosely coupled by virtue of relevance. Unfortunately, there is not an easy way to tie these related services together to fulfill an e- business opportunity (an e-business process). In this position paper, we argue that the ad-hoc workflow and mobile agent technologies can enable e-business processes over loosely coupled web-based services. We present our ideas in the context of an order processing application in supply chains. We also present the architecture and implementation of a simple mobile-agent-based ad-hoc workflow system. Keywords: Ad-hoc workflow, Mobile agents, e- services, service brokering. 1 Introduction Workflow management (WFM) is an enabling technology for the automation and integration of process-oriented tasks. In a WFM system, a workflow model (workflow type) is predefined for each business process. A workflow model consists of a number of activities and a set of conditional transitions that link these activities together. No assumption is made about the location of activities that could potentially be spread across the network, especially in inter-organizational workflow systems. In this paper, we present a design and an implementation of an ad-hoc workflow system based on the mobile agent technology. Unlike traditional WFM systems [2], in ad-hoc workflow, there is no predefined workflow model for the business process. The business process is built ad-hocly as it is enacted using distributed services (activities). Business rules, which capture invariant inter-service logic, are associated with the services and are used to determine the next activities to be performed on behalf of the business process. The main advantage of ad-hoc workflow systems is that the business process can be built dynamically and flexibly. Another advantage is the ability of ad-hoc workflow to cope with dynamic changes in business rules and service definitions, implementations, and/or locations. The service providers taking part in the ad-hoc workflow are not required to be dedicated services. They could be cooperative services in an organization’s Intranet, or could very well be loosely coupled e-commerce services. With the emergence of business to business e-commerce, a new breed of business processes that relies on multiple independent web-based services is created. We call these processes "e-business processes". We argue that ad-hoc workflow modeling is most appropriate for e-business processes. We further argue that mobile agents [3][7][8] are very well suited for enacting ad-hoc workflow applications across loosely-coupled web-based services. The critical aspect that makes mobile agents suitable for this kind of workflow is their ability to move ad-hocly to local services. Without mobile agents, such web-based services would have to be integrated and designed as distributed cooperative services that are able to communicate with a remote workflow engine. With mobile agents, this requirement is simply waived. Another important advantage for using mobile agents in ad-hoc workflow systems based on web services is the suitability of asynchronous communication in this environment. Web-based services are usually not real-time tasks and often involve human operators who connect to the Internet only sporadically. Synchronous communication such