Social adaptation: When software gives users a voice

Adaptive systems are characterized by the ability to monitor changes in their volatile world and react to monitored changes when needed. The ultimate goal of adaptation is that users' requirements are always met correctly and efficiently. Adaptation is traditionally driven by the changing state of the system internal and its surrounding environment. Such state should be monitored and analyzed to decide upon a suitable alternative behaviour to adopt. In this paper, we introduce another driver for adaptation which is the users' collective judgement on the alternative behaviors of a system. This judgmenet should be infered from the individual users' feedback given iteratviely during the lifetime of a system. Users' feedback reflects their main interest which is the validity and the quality of a system behaviour as a means to meet their requirements. We propose social adaptation which is a specific kind of adaptation that treats users' feedback, obtained during the software lifetime, as a primary driver in planning and guiding adaptation. We propose a novel requirements engineering modelling and analysis approach meant for systems adopting social adaptation. We evaluate our approach by applying it in practice and report on the results.