By the acronym MOCOCO we refer to our view of ambient intelligence (AmI), pointing out three main characteristics: Mobility, contextualization and Collaboration. The ambient intelligence is a challenging research area focusing on ubiquitous computing, profiling practices, context awareness, and humancentric computing and interaction design. We are concretizing our approach in a platform called IMERA (French acronym for Computer Augmented Environment for Mobile Interaction). In order to make work together several sensors, actuat ors and mobile smart devices, the need of a context-aware middleware for this platform is obvious. In this paper, we present main objectives and solution principles concretized in a context-aware middleware based on hybrid reasoning engine (the ontology reasoning and the decision tree reasoning), which retrieves efficiently high-level contexts from raw data. This platform provides an environment for rapid prototyping of context aware services in Ambient Intelligent (AmI)