A Web Services Based Architecture for Supporting Mobile Users in Large Enterprises

Business enterprises can proficiently benefit from Ubiquitous Computing (UbiComp). UbiCompenvironments enable mobile users to access services and resources in a transparent and spontaneous way,that is, without any configuration operation and through very friendly user-environment interfacemechanisms which sometimes anticipate user needs. Unfortunately, until now the UbiComp model hasbeen applied only to environments bounded to a specific site. In order to support large enterprises, whichmay have several offices spread over a wide geographic area, this model needs to be extended with basicservices that enable the realization of federations of environments. In other words, in the case of multiofficeenterprises, each office could be equipped with a classic UbiComp environment; however, suchenvironments must be interconnected by the internet and co-ordinated by a set of higher level services. Asa matter of fact, in this case mobile users not only have to get access in a transparent and spontaneous waybut, also, they should have the possibility of leaving a physical site without concern of their pendingcomputations and, successively, they should be enabled to come back in the environment, even in adifferent site, and resume their computations. As a consequence, locating mobile users and handling theirdisconnections becomes a very critical requirement. Indeed, differently from a classic UbiCompenvironment, in a federation of UbiComps resources can not be merely released when a mobile userleaves. Instead, the global environment has to infer user's intentions in order to understand whether he willcome back to resume computations, or not.In this paper, we propose a Web Services based architecture for federating classic UbiComp environments.This architecture supports large enterprises with functionalities for locating and tracking mobile users in afederation of UbiComp environments. These services implement specific strategies that have been devisedto allow i) mobile users to leave a physical site with no concern of their pending computations; ii) theglobal environment to locate and track users in the federation of UbiComp environments; iii) mobile usersto come back in the federation and resume their computations and iv) the environment to reliably handleresources by inferring users intentions.