Runtime Controller Synthesis for Self-Adaptation: Be Discrete! (Keynote)

Self-adaptation is often defined as the ability of systems to alter at runtime their behaviour in response to changes in their environment, capabilities and goals. In this talk I will argue that this definition is too broad and that it dilutes a very real need for a particular quality of today's software systems. I will postulate that a more refined definition of adaptation should emphasise the need for systems to have the ability to react to changes that were originally unforseen at design time, and to provide assurances on the correctness of these adaptations. How can systems be designed to account for what is unforseen? I will argue that a key design decision for achieving self-adaptation is to endow systems with the capability of synthesising at runtime discrete event controllers. Indeed, reactive systems that are requirements and assumptions aware, if extended with run time controller synthesis capabilities are equipped with a powerful infrastructure towards achieving assured self-adaptation.