Mohammed Abufouda

• Self-adaptation allows software systems to autonomously adjust their behavior during run-time by handling all possible operating states that violate the requirements of the managed system. This requires an adaptation engine that receives adaptation requests during the monitoring process of the managed system and responds with an automated and appropriate adaptation response. During the last decade, several engineering methods have been introduced to enable self-adaptation in software systems. However, these methods lack addressing (1) run-time uncertainty that hinders the adaptation process and (2) the performance impacts resulted from the complexity and the large number of the adaptation space. This paper presents CRATER, a framework that builds an external adaptation engine for self-adaptive software systems. The adaptation engine, which is built on Case-based Reasoning, handles the aforementioned challenges together. This paper is braced with an experiment illustrating the benefits of this framework. The experimental results shows the potential of CRATER in terms handling run-time uncertainty and adaptation remembrance that enhances the performance for large number of adaptation space.