Today 23 May 2007, I am flying back to Stockholm after a four weeks trip to Brisbane, Australia and
an informal visit to the BPM group at QUT. During my stay in Brisbane I cooperated with A/Prof. Arthur ter
Hofstede and Nick Russell on a deep analysis of OpenWFE, which is one of the
mainstream open-source workflow management systems (WFMSs). We also briefly discussed
an initial analysis of jBPM which is another open-source WFMS.
I used the opportunity to consult Lachlan Aldred, who is the main developer of the YAWL Engine, about custom YAWL services and the development of a database YAWL service.
During these weeks, I also had the opportunity to attend the final PhD seminars of Nick Russell and Michael Adams. Nick presented and defended his thesis on: (i) extensions to the Workflow Patterns framework with
Data, Resource and Exception handling patterns as well as a revision and
formalisation of the original Control-flow patterns; and (ii) a further
development of the language YAWL, which was developed based on the Workflow
Patterns, into newYAWL – a version capturing the extensions introduced into the
Michael presented his work on exception handling and dynamic workflow. In his thesis he proposes a framework enabling the on-the-fly change of executing business processes. The framework takes some ideas from Activity
Theory, which is a theory about work organisation developed in the USSR during the
1920s, and uses them to develop guiding principles for workflow management
systems. It uses the concept of Worklet, which is a small independent (sub)
process. During execution of a task, the appropriate worklet is selected based
on context information organised in the form of so-called Ripple Down Rules. As
time goes by, these rules may be extended and also new worklets may be added.
In addition, the same framework is used for exception handling where Exlets
form exception handling processes using concepts developed by Nick Russell that
may be invoked depending on the type of exception occurring. The whole
framework has been implemented in YAWL but is general enough so that it could
be transferred to any workflow management system offering the required