Abstract for Andrzej Cichocki Name: Andrzej Cichocki Organization: MCC E-mail: Go to the bio

Migrating Workflows Utilizing Transportable Agents

Andrzej Cichocki CMI Project MCC 3500 West Balcones Center Dr. Austin, TX 78759

e-mail: andrzej@mcc.com

Migrating workflows implement the computational metaphor that is similar to the way most people conduct their daily business: they visit a place, use a service (perhaps after some negotiation), and move on to the next place. The migrating workflow behaves similarly: it transfers its code (specification) and its execution state to a site, negotiates a service to be executed on its behalf, receives the results, and moves on. The next place visited by the workflow, and the next service requested, is determined by both the goal of the process, and the results of the current requests. Results of a request can be influenced by the site and/or the site's user. Thus the actual workflow instance is defined during the run-time, as an effect of merging the static workflow specification, the local rules and policies, and the decisions made by the user.

The strength of migrating workflows lies in their ability to react dynamically to an ever-changing environment. A change in company policy will no longer require rewriting all affected workflows. A simple modification of a local rule at a single site will suffice to implement such a change. The flexibility of migrating workflows allows for more robust handling of failures and exceptions, and consequently, for more reliable workflow execution systems. The migration of workflows provide a graceful way of handling disconnected operations in mobile computing environment. Finally, in cases where a workflow needs to process large sets of data, migrating workflows improve system performance by transferring a short workflow specification to sites where huge datasets reside, rather then moving the data.

As we can see the principles of migrating workflows match very closely these of transportable agents. Therefore, the CMI project in MCC is interested in use of the transportable agent technology as underlying mechanism for the implementation of the migrating workflows.

However, there are few disadvantages related to the use of transportable agent technology. One of the most important is the difficulty of providing proper security for both the sites executing the workflow instances and the workflows themselves. Also the administration and monitoring of migrating workflows seem to be difficult problems. We hope that the advances in the transportable agents area will help overcoming these disadvantages.