  We envisage future context-aware applications will dynamically adapt their
behaviors to various context data from sources in wide-area networks, such as
the Internet. Facing the changing context and the sheer number of context
sources, a data management system that supports effective source organization
and efficient data lookup becomes crucial to the easy development of
context-aware applications. In this paper, we propose the design of a new
context data management system that is equipped with query processing
capabilities. We encapsulate the context sources into physical spaces belonging
to different context spaces and organize them as peers in semantic overlay
networks. Initial evaluation results of an experimental system prototype
demonstrate the effectiveness of our design
