TOWARDS UML-RT BEHAVIOURAL CONSISTENCY Kawtar Benghazi Akhlaki, Manuel I. Capel Tu˜ n´ on, Juan A. Holgado Terriza Departamento de Lenguajes y Sistemas Inform ´ aticos, ETSI Inform ´ atica, Campus Aynadamar Universidad de Granada, 18071 Granada, Spain Luis E. Mendoza Morales Departamento de Procesos y Sistemas, Edificio de Matem´ aticas y Sistemas Universidad Sim´ on Bol´ ıvar, Apartado 89000, Baruta, Caracas,1080-A, Venezuela Keywords: Timed Sequence Diagram, State Diagram, Formal semantics, CSP+T, Timed Traces. Timing Constraints. Abstract: Having an objective of achieving a formal characterisation of Sequence Diagrams (UML-SD) as a means for Embedded Real-Time software systems ( ERTS ) development and validation, this paper introduces a CSP+T- based timed trace semantics for most concepts of SD. A trace is sequence of events, which gives the necessary expressiveness to capture the standard interpretation of UML SD. Timed SD (TSD) depict work flow, message passing and gives a general view of how system’s components cooperate over time to achieve a result. Such sequence, often called an scenario, also represents a part of the system behaviour and a possible execution of a state machine. State machines and SD are used as complementary models for describing system behaviour. 1 INTRODUCTION Embedded Real-Time software systems , such as in- dustrial control systems or automotive systems, get progressively more complex. Often, major sources of the complexity are interactions between the dis- tributed system components. The Unified Modelling Language (UML) (Selic and J, 1998) has become the de-facto standard for modelling systems. The ver- sion 2.0 (OMG, 2004) of the UML enhances the pos- sibility of modelling complex and hierarchical inter- actions. It provides flexible and powerful constructs and operators to express conditions, parallel execu- tion, repetition and hierarchy. Sequence Diagrams (SD) are defined in the UML 2.0 for specifying in- teraction between communicating objects represented by lifelines and they are used in a number of differ- ent stages during ERTS development process. It is important that the precise meaning of SD is well un- derstood by all the stakeholders of a system under development; in other words, there is a need for a well-defined semantics of SD. Having as objective to achieve a formal characterization of SD as a means for ERTS development and validation, this paper in- troduces a CSP-based timed trace semantics for most concepts of SD. 2 RELATED WORK There are several other formal trace semantics inter- pretations of SD that have been considered before. In (Haugen, 2005) STAIRS addresses all the operators to combine fragments of SD with different behavior. The temporal view of SD is not complemented with richer timing expressions than the standard UML an- notations. This approach can be considered comple- mentary with our work, since our approach tends to integrate SD with other UML 2.0 analysis artifacts, such as state machine, in order to yield an integrated dynamic object-oriented model of an ERTS accord- ing to the development process proposed in (Capel et al., 2005). The work of X.Li et al (Li et al., 2004) presents a formal semantics of SD in the context of a class diagram that is also formalized. The dynamic semantics of a conceptual system model is captured by a classical flat deterministic state machine. By giv- ing a formal semantics to both SD and state machine, it can be checked whether an SD realizes a use case of the system conceptual model. No temporal view of the SD or the state machine is addressed there. Other general contributions based on the formaliza- tion of the dynamic model that describes the behavior of different types of systems have been carried out in the OMT’s dynamic model (Cheng, 2002) and UML’s 612 Benghazi Akhlaki K., I. Capel Tuñón M., A. Holgado Terriza J. and E. Mendoza Morales L. (2007). TOWARDS UML-RT BEHAVIOURAL CONSISTENCY. In Proceedings of the Ninth International Conference on Enterprise Information Systems - ISAS, pages 612-615 DOI: 10.5220/0002395006120615 Copyright c  SciTePress