||Dependable systems are more and more expected to operate in dynamic environments to deal with the new problems and tasks. One way of achieving
flexibility of the system is to use dynamic reconfiguration. A system can
be implemented as a collection of configurations, where each configuration can
be optimized for each service. Therefore, dynamic reconfiguration can provide
exibility of the system by replacing one configuration by another
at runtime. Furthermore, it makes the system more dependable because the
overall architecture of the system has not been changed by adding or removing
configurations. However the problem of interferences between the old and the
new configurations needs to be addressed. The purpose of our research is to design, model, verify and implement a case study involving the reconfiguration of
an office workflow for order processing, based on the requirements on a system
implementing the work
ow and its reconfiguration.
In this thesis, we design a system for an example of an office workflow using the
Business Process Modeling Notation (BPMN), which is a widely used graphical
tool for designing business processes. Applications that provide specific business functions are being exposed as Web services. These services are reusable
components that can build business processes. In order to facilitate the design
of business processes, Business Process Execution Language (BPEL) is used.
BPEL is an XML-based work
ow language that uses basic and structured activities to describe the logic of a business process. We present and discuss a
mapping from BPMN model to BPEL process based on the identication of
patterns of BPMN fragments which can be directly mapped onto BPEL code.
We also use an automatic tool to do the same translation and try to find the
differences between these two mapping ways. In this work, we investigate also
whether or not the design will meet the reconfiguration requirements and discuss
the strengths and weaknesses of BPEL in modeling dynamic reconfiguration. We
include with a discussion of an alternative design and motivate why we find the
alternative less suitable for this project.
This thesis has been developed in the context of an international research collaboration on "Evaluation of Formalisms for Dynamic Reconfiguration of an Office
Workflow: Design, Modeling, Analysis and Implementation" among Embedded Systems Engineering Section, DTU Informatics, Technical University of Denmark (DTU)
, and Reconfiguration Interest Group at Newcastle University, Newcastle upon
Tyne, UK, and CRAC Laboratory at Ecole Polytechnique de Montreal, Montreal, Canada, and Department of Computer Science and System Engineering, Faculty of Engineering (CPS) , University of Zaragoza.
The joint project focuses on design, modeling, analysis and implementation of
an office work
flow case study, in particular, on evaluating several well-known
formalisms for their suitability for reconfigurable dependable systems. This
thesis has mainly accomplished the design and implementation of the case study
and its reconfiguration.
Preliminary results of the project have been submitted to the 13th International
Conference on Coordinating Models and Languages (COORDINATION'2011).
The submitted paper is included in Appendix A.