Validation of UML Design Model

Ensuring absence of design model inconsistencies that may lead to errors creeping in software, is a major challenge of software development. Further, these errors may propagate to the different phases of software development life cycle models. Correct design rules help in developing consistent design models of software. A way to ensure the correctness of design models is through its validation. Validation of design models is based on validated design rules. This work proposes a method based on predicate logic for validation of design models. The method has been illustrated with the help of a verified case. In this paper, a method based on predicate logic is presented to determine the inconsistency in the UML design models. Modeling languages for design such as UML, follows various constraints. Constraints have been used for the various purposes such as representing modeling philosophies, reflecting restrictions of domain and application needs as being part of UML. In this paper, we use the term design rule to denote such constraints. A design rule consists of constraints that validate to either true (consistent) or false (inconsistent) to reflect whether the model satisfies given rules or not. An inconsistency is a sign of problem and the element that causes the inconsistency needs to be resolved. So, all model element's properties that causes inconsistency must be identified to address them. An accurate visualization of the cause can contribute to a better design process, which avoid further errors. The proper understanding of the cause may help to focus on the repair of those parts of the model which contributed to the inconsistency. This paper focuses on the problem of validating design rules for UML design models. Design model's properties may be specified with design rules. These design rules need to be formalized, if they are required to be validated. Design rules can be expressed through OCL (Object Constraints language). OCL constraints are converted into predicate logic for the validation of design rules. Predicate logic expressions of design rules are validated through tableaux method. Predicate logic has been used for validation of model as it is rigorous language and captures models precisely. Validation of UML design models using design rules concerning re-usability is the main goal of the work.