This paper presents Contory, a middleware specifically deployed to support provisioning of context information on mobile devices such as smart phones. Contory integrates multiple strategies for context provisioning, namely internal sensors-based, external infrastructure-based, and distributed provisioning in ad hoc networks. Applications can query Contory about context items of different types, using a declarative query language which features on-demand, periodic, and event-based context queries. Contory allows applications to utilize different provisioning mechanisms depending on resource availability and presence of external infrastructures. This paper illustrates our approach along with its design and implementation on smart phones.
This work addresses the gap regarding existing indoor location-awareness support solutions and their integration in real-world smart spaces composed of commodity mobile/fixed devices. The work describes experiences and lessons learnt in designing and implementing support for indoor location-based services within the framework of our research about smart space application platforms. The extensive usage of web technologies in our smart space application platform enables easy creation and mash-up of location based services in both ad hoc settings and interconnected environments. As for the indoor location sensing, the solution relies on a novel technique that is suitable for easy large-scale deployments on top of existing IEEE 802.11 wireless network infrastructures. The technique, which is based on received signal strength (RSS), is suitable for RSS measurements and location calculation to take place at the mobile terminal with minimum setup work. In addition, it does not require any proprietary hardware devices to be installed in the target environment. Experimental results, referring to different categories of mobile devices (commercial smartphones, PDAs and laptops), show that the technique performs quite well on commodity mobile devices in terms of power consumption and time required to calculate the indoor location.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.