Functional software architecture: Difference between revisions

Revision as of 14:58, 21 May 2006

Revision as of 21:07, 13 July 2006

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Petri Nets are known tools to model manufacturing systems [9]. They are highly expressive and provide good formalisms for the modelling of concurrent systems. The most advantageous properties are that of simple representation of states, concurrent system transitions and capabilities to model the duration of transitions.

Petri Nets therefore can be used to model certain business processes with corresponding state and transitions or activities with in and outputs. Moreover, Petri Nets can be used to model different software systems and transitions between these systems. In this way programmers use it as a schematic coding reference.

In recent years a number of attempts have shown that Petri Nets can contribute to the development of business process integration. One of these is the Model Blue methodology, which is developed by IBM Chinese Research Laboratory and outlines the importance of model driven business integration as an emerging approach for building integrated platforms [10]. A mapping between their Model Blue business view and an equivalent Petri Net is also shown, which indicates that their research closes the gab between business and IT. However, instead of Petri Nets they rather use their own Model Blue IT view, which can be derived from their business view troughthrough a transformation engine.

So, pros and cons in using Petri Nets as a modelling tool for the implementation of integrated IT systems are present. Maybe it should be combined with other methods and techniques to deliver positive results? For instance, various classes of Petri Nets can be used in combination with IDEF or CIMOSA and even UML [11]. Mostly to exercise alternative system design. However, a major drawback of Petri Nets, the inability to provide multiple views of entire enterprise systems, remains.

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===Enterprise Function Diagrams===

EFD is a used modeling technique for the representation of enterprise functions and corresponding interactions. Different business processes can be modeled in these representations through the use of “function modules” and triggers. A starting business process delivers different inputs to different functions. A process flowing through all the functions and sub-functions creates multiple outputs. Enterprise Function Diagrams hereby give a very easy-to-use and detailed representation about a business process and corresponding functions, inputs, outputs and triggers.

In this way EFD has many similarities with IDEF0 diagrams, which also represent in a hierarchical way business processes as a combination of functions and triggers. Difference is that an EFD places the business functions in an organization hierarchical perspective, which outlines the downstream of certain processes in the organization. On the contrary, IDEF0 diagrams show responsibilities of certain business functions troughthrough the use of arrows. Also, IDEF0 has a clear representation of inputs and outputs of every (sub)function.

Figure 4 shows an EFD of a publish company producing books and CD-ROMs for educational purposes. It gives a clear view of a publication process within an organization: