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Matching of ebXML business processes
Dennis Krukkert
Editor's note: Dennis Krukkert, working with the openXchange project under the tutelage of the Physics and Electronics Laboratory of the Netherlands Organisation for Applied Scientific Research (that uses the Dutch acronym TNO-FEL), prepared a paper that outlines a methodology for matching business processes in ebXML. Krukkert's paper also served as the thesis for his Master's degree at University of Twente in the Netherlands. We thank Dennis Krukkert and Erwin Folmer of TNO-FEL for providing a summary of the paper. The full report is available from the project's Web site.
EbXML is a relative new standard that presents a framework for doing electronic business. One of the things that distinguishes ebXML from other standards is the possibility for a company to specify its profile and publish this in a public registry. Part of this profile is a description of the business processes supported by a company. When a company is looking for a business partner, it can compare its profile to those of other companies. Before two companies can start doing business, an agreement has to be formed. Part of this agreement is the specification of supported business processes.
Currently agreements can only be formed if two companies reference the same business processes. This way of forming agreements implies that two companies that reference different business processes can never do business together. This report describes a different approach to the use of business processes and shows that companies may be able to do business even though they reference different process specifications. In order to detect whether or not two companies are able to do business, business processes have to be matched. The matching of two business processes always results in the creation of a third business process that represents the "agreement" of two business processes. Within the openXchange project, efforts are made to create a system that can automatically create an agreement between two profiles. The automated generation of an agreement between two profiles should include the matching of business processes so that the agreement between profiles can references the agreement between business processes.
Before a solution can be created to match two business processes, it has to be clear what a successful match is. A business process specification can be considered as a specification of all possible business scenarios. Within this report, we use the definition that two business processes match if there is at least one business scenario that is supported by both business processes. An algorithm is presented that takes two business processes as input. The result is a third business processes that describes all possible business scenarios supported by both input processes. If the newly created business process contains at least one successful business scenario, the match is considered successful.
In ebXML, a business process specification describes a number of activities and a ordering of these activities in relation to each other. The problem of matching is twofold: both ordering of the activities (or structure) and the content of activities have to be matched.
In ebXML, a business process specification describes a number of activities and a ordering of these activities in relation to each other. The problem of matching is twofold: both ordering of the activities (or structure) and the content of activities have to be matched.
EbXML uses UML activity diagrams to specify the structure of business processes. In order to solve the problem of matching structure, a solution has to be found for matching activity diagrams. A number of existing techniques for matching are examined, but none of these can handle parallelism. Activity diagrams offer the possibility to introduce parallelism, so in order to match activity diagrams, a solution has to be found to match parallelism. The solution presented in this report first converts activity diagrams into State Transition Systems (or STS). This conversion increase the complexity of the business process specification, but models the parallelism in such a way that a technique called "intersection" can be used to match two diagrams. The intersection of two STS diagrams is also a STS diagram and can be converted back into an activity diagram. The newly created activity diagram represents the match of two original activity diagrams.
Each activity within an ebXML business process specification describes the exchange of one or more documents. In order to match the content of activities, documents have to be matched. Documents are created using standardised building blocks called Business Information Entities. Matching of documents is done by matching the Business Information Entities used in the documents. The matching of Business Information Entities includes matching of both semantics and context. In order for two Business Information Entities to match, they must at least have the same semantics. If this is true, then the context of two Business Information Entities is matched. To simplify future implementations of the matching algorithm, a suggestion is made to a specific use of qualifiers, a mechanism to differentiate two Business Information Entities that have the same semantics but exist in a different context.
Even though this reports shows that automated matching of business processes is possible, there are still some problems that need to be solved. Some of the problems originate from the ebXML specifications and suggestions are made to adjust the specification in order to allow automated business process matching. Other problems come forth from features that are required to create useful business process specifications but increase the complexity of matching. One of the major (and for time reasons yet unsolved) problems is that of matching logical expressions used for pre and post conditions.
Solving the earlier mentioned problems and implementing the matching of business processes within the ebXML framework will increase functionality and decrease the complexity of implementing ebXML by end-users. This will contribute to the objectives of both ebXML and openXchange: an cross-industry e-business standard that can be used by companies of any size, anywhere on the globe.
For more information ...
Full report: http://www.tno.nl/instit/fel/ts/exp/e-business.html
openXchange: http://www.openXchange.org
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