Location-dependent services for mobile users

Several approaches for the provisioning of servicesto mobile users aim at supporting service availability from anyplace and at any time. However, most scenarios also require theenforcement of context-awareness, to dynamically adapt servicesdepending on the context in which they are requested. In thispaper, we focus on the problem of adapting services dependingon the users’ location, whether physical (in space) or logical(within a specific distributed group/application). To this end, wepropose a framework to model users’ location via a multiplicityof local and active service contexts. First, service contextsrepresent the mean to access to services available within aphysical locality. This leads to an intrinsic dependency ofservice provisioning on the users’ physical location. Second, thebehavior of service contexts can be tuned depending on who isrequesting what service. This enables adapting services to thelogical location of users (e.g., a request can lead to differentbehaviors for users belonging to different groups/applications).The paper firstly describes the framework in general terms,showing how it can facilitate the design of distributedapplications involving mobile users as well as mobile agents.Then, it shows how the MARS coordination middleware,implementing service contexts in terms of programmable tuplespaces, can be used to develop and deploy applications andservices coherently with the above framework. A case study isintroduced and discussed through the paper to clarify ourapproach and to show its effectiveness.