Towards Performance Evaluation of Mobile Systems in UML

The current generation of network-centric applications ex- hibits an increasingly higher degree of mobility. Wireless networks allow devices to move from one location to another without loosing connectivity. Also, new software technolo- gies allow code fragments or entire running applications to migrate from one host to another. Performance modeling of such complex systems is a difficult task, which should be carried out during the early design stages of system devel- opment. However, the integration of performance modeling analysis with software system specification for mobile sys- tems is still an open problem, since there is no unique widely accepted notation for describing mobile systems. Moreover performance modeling is usually developed separately from high-level system description. This is not only time con- suming, but the separation of performance model and system specification makes more difficult the feedback process of re- porting the performance analysis results at the system design level, and modifying system model to analyze design alter- natives. In this paper we address the problem of integrating system performance modeling and analysis with a specifica- tion of mobile software system based on UML. In particular we introduce a unified UML notation for high-level descrip- tion and performance modeling of mobile systems. The no- tation allows inclusion of quantitative information, which are used to build a process-oriented simulation model of the sys- tem. The simulation model is executed, and the results are reported back in the UML notation. We describe a prototype tool for translating annotated UML models into simulation programs and we present a simple case study.