UML 2.0 interactions with OCL/RT constraints

The use of formal methods at early stages of software development contributes to the reliability and robustness of the system to be constructed. Int his context, real-time system development benefits from the construction of behavioral models in order to verify the correct satisfaction of time constraints. The Unified Modeling Language (UML) is a software specification language widely used by the industry and the academia. Nevertheless, its version 2.0 lacks a formal semantics for the development of provably-correct models. In addition, its constraint specification language, Object Constraint Language (OCL), has limitations for its use in behavioral models of real-time systems. This work concerns the inter-component behavioral specification of real-time systems. Such behavior is described using the UML 2.0 Interactions language extended for the inclusion of time constraints using the OCL for Real Time (OCL/RT) language. The main problem addressed in this work is the definition of a formal semantics for the fusion of both languages. The semantics allows recognizing valid and invalid behaviors of a system with time constraints. Intended for formal verification, an analysis of the properties derived from the semantics is also done. In particular, the notions of refinement of interactions and refinement of constraints are explored. Finally, the proposal is compared with related works and its practical application is studied in order to analyze its benefits and weaknesses. This work contributes to the formalization of concepts widely used in practice and, inconsequence, to its inclusion in modeling and formal reasoning tools. More-over, the expressivity of the UML 2.0 Interactions language is augmented in order to support complex real-time constraints, not expressable until this moment

Enhancement of natural language processing approach for automated generation of object constraint language

Object Constraint Language (OCL) is the most prevalent modeling language to document requirement constraints that are annotated in the Unified Modeling Language. Various researchers have proved that OCL syntax is complex and difficult for some reasons such as its declarative nature. As the measure of ease-of-use factor of a language has a direct relationship with the language’s usability, the difficulties in the use of OCL result in the low usability of OCL. There are few research works for OCL generation using some different techniques such as pattern-based and Model-Driven Architecture (MDA)-based. The accuracy of the existing patternbased work generating OCL specification is low. MDA focuses on software development based on generating models and transforming these models between each other. There are some researches based on MDA to increase the usability of modeling languages. However, only one of the existing works supports OCL. The existing MDA-based work generating OCL specification does not support some OCL elements, such as collect and reject, and some UML elements such as enumeration. Therefore, this research proposes an MDA-based approach to transform requirement constraints formed in English sentences into OCL specifications using transformation rules. A software tool is developed to validate the proposed approach and compare with the existing works. The comparison shows that the proposed approach solves some limitations of the existing works such as support of some OCL and UML elements, which are not supported by the existing works. The comparison also shows that some accuracy improvement is achieved by the proposed approach in comparison with the existing works