MODELING OF DATA FLOW DIAGRAMS USING PETRI NET MODEL

Abstract

In this dissertation, an approach to the modeling and implementation of data flow diagrams (DFDs) using the Petri net model is introduced. A direction is identified where visualisation and high-level semantics can be incorporated into data flow diagrams to allow direct manipulation, interpretation and validation. At the automation level, visualised DFDs generate layouts for data flow vectors and use Petri net to safeguard the correctness of a specification. The Petri net model uses a set of constraints to maintain consistency both within and across diagrams. At the visual level, visualised DFDs replace the traditional textual specifications of the process and data flow components with graphical forms. It adopts the Entity-Relationship model as the hierarchical and logical view of data. In this paper, the Place-Transition net has been modified to model visualised DFD. A form generator has also been revised to generate graphical forms for the data flow and process specifications. Finally, a layout algorithm has been developed to generate layouts for the data flow components.