QoS-Based Model Driven Assessment of Adaptive Reactive Systems

Adaptable reactive software systems continuously interact with their environment responding to external stimuli and triggering events that may be perceived by their users. Designing and maintaining such systems is a challenging task. A key issue to be faced concerns the assessment of their effectiveness, in terms of the ability to meet their required Quality of Service. This paper introduces a model driven approach to support this assessment, with a focus on performance and dependability attributes. Our approach takes advantage from an existing intermediate modeling language and introduces the necessary extensions to cope with reactive systems. The presented model driven framework exploits the idea of defining a model transformation chain that maps a design oriented model of the system to an analysis oriented model that lends itself to the application of a suitable analysis methodology. We identify some key concepts that should be present in the design model of an adaptable reactive system, and show how to devise a transformation from such a model to a target analysis models.