Abstract. A major challenge of Ambient Intelligence lies in building middleware that can ease service implementation through allowing the application developer to emphasize only the service logic. In this paper we describe the architecture of an Ambient Intelligence system established in the scope of the European research project CHIL (Computers in the Human Interaction Loop). CHIL aims at developing and realizing computer services that are delivered to humans in an implicit and unobtrusive way. The framework presented here supports the implementation of human-centric context-aware applications. This includes the presentation of the sensors used in CHIL spaces, the mechanisms employed for controlling sensors and actuating devices, as well as the perceptual components and the middleware approach for combining them in the scope of applications. Special focus lies on the design and implementation of an agent based framework that supports “pluggable” service logic in the sense that the...