In MUSIC, adaptation is defined as the activity of adjusting to varying contexts. Adaptation is needed when there is a mismatch between the quality of the services provided by the application and the user needs, or between the application needs and the context. Adaptation may lead to a degradation or enhancement of the quality of the provided services (QoS). For instance, the functional richness of an application may be modified, or the response time of a service may be reduced.