Modeling System Requirements Using Use Cases and Petri Nets

Object Oriented Petri Nets; Use Cases; requirement specification; requirement implementation

The fundamental problem associated with software development is a correct identification, specification and subsequent implementation of the system requirements. To requirement specifications, designers often creates use case diagrams from Unified Modeling Language (UML). These models are then developed by further UML models. To validate requirements, its executable form has to be obtained or the prototype has to be developed. It can conclude in wrong requirement implementations and incorrect validation process. The approach presented in this work focuses on formal requirement modelling combining the classic models for requirements specification (use case diagrams) with models having a formal basis (Petri Nets). Created models can be used in all development stages including requirements specification, verification, and implementation. All design and validation steps are carries on the same models, which avoids mistakes caused by model implementation.

One of the fundamental problems associated with software development is a right identification, specification and subsequent implementation of the system requirements. The use case diagram from UML is often use for requirements specification, which is then developed by further UML models. The disadvantage is the inability to check a specification modeled by that method and it is usually necessary to develop a prototype, which is no longer used after fulfilling its purpose. There are methods of working with modified UML models that can be executed and, therefore, check. An example is the MDA methodology and language xUML. However, these methods use transformation techniques to obtain different types of models that serve to different purposes (specification, simulation, etc.). When verifying, the developer does not work with original models and has to reflect any modifications to the original model. This work focuses on the use of Petri nets for specifying requirements. Petri nets are the same specification and implementation of system requirements, so that it is not necessary to implement prototypes or transform models. Any changes are always carried over the same model.