Client-proxy-server model to support disconnected operations in wireless environments using semantic caching

The rapid development of wireless communication technologies and their impact on everyday life has greatly increased in the last years. The increasing number of mobile wireless computers users will highly appreciate the ability of their equipments to operate disconnected, since they may often be disconnected from the fixed network either forced, due to relocations, or willingly, when the cost of using a connection is very high. The traditional client-server architecture, in which the client relies completely on the server for servicing its requests, is not appropriate for the wireless environment because, during the periods of disconnection, the server is unreachable. This thesis proposes a client-proxy-server model in which a client-side proxy assumes the role of a local server during the disconnections. The proxy manages a semantic cache which will be used to satisfy the wireless client's requests during the disconnections, and to also reduce the data transmission over the wireless link when the connection to the server is established by retrieving partial results for the user queries directly from the local cache.