MediateSpace: decentralised contextual mediation using tuple spaces

With almost four billion sensor-equipped mobile devices on the planet, the way is open for a variety of new context-based applications and services. However, this new opportunity creates concerns over privacy and access control and necessitates a robust and scalable solution. We propose the MediateSpace middleware which is a decentralised tuple space with contextual mediation capabilities for both data distributors and consumers. Distributors may restrict access by requiring the satisfaction of a contextual condition and consumers may restrict which data enters their computer (tuple conditions). Distributed X-Trees (a development of R-Trees) are used to achieve decentralisation. The system also provides Restricted Context Sharing, Triggers (performing actions upon matching certain conditions or data pat- terns), Module Handlers (simplifying the processing of received messages), Context Scripting (allowing the dynamic addition, re- moval or augmentation of structures such as triggers) and State Management (allowing state to be read and stored semi-persistently). MediateSpace could be used to support a myriad of possible applications such as context dependent data collection, collaborative tools for geographically co-located individuals and context-aware file-sharing.