CONTEXT MANAGEMENT FOR THE PROVISION zy OF ADAPTIVE SERVICES TO ROAMING USERS STAVROS A. XYNOGALAS, MARIA K. CHANTZARA, IRENE C. SYGKOUNA, STAVROS P. VRONTIS, IOANNA zyxwv G. ROUSSAKI, AND MILTIADES E. ANAGNOSTOU NATIONAL TECHNICAL UNIVERSITY OF ATHENS (NTUA) zyx 1 - zyxwvutsrqponmlkj L- ~- Roaming users will expect continuous access to personalized services from any place, transparently and independent of the underlying network technology and the terminal or point of access. VHE feotures were specified and implemented to satisfy these requirements in zyxwvutsrqpo 36 systems. zyxwvutsrqpon I zyxwvutsrqponmlkjihgfedcba This zyxwvutsrqpon work was supponed by the IST CONTEXT project, panidly funded by rhe EC. ABSTRACT Various types of sophisticated networks and terminals are used for the provision of third- generation services, and even more complicated ones are designed for 4G systems. Roaming users will rely on new kinds of wireless networks and terminals to offer mobility and make multi- media services available everywhere. They will, of course, expect continuous access to personal- ized services from any place, transparently and independent of the underlying network technol- ogy and the terminal or point of access. Virtual home environment features were specified and implemented in order to satisfy these require- ments in 3G systems. The enhanced role of IP in 4G systems and the assimilation of WLAN technology will enable further advances toward pervasive computing and the pursuit of corn-, plete context awareness in state-of-the-art appli- cations and services. 4G services can he smarter and more adaptive by taking advantage of all types of context available to them within a well defined context management framework. This article presents results from work carried out over the last few years at NTUA,’ bringing us closer to the definition of such a flexible frame- work for cfficient management of content, which will he able to support the development of advanced telecommunications services and inte- grated real-time information provision and pro- cessing systems. INTRODUCTION The transition to a world of ambient intelli- gence, a vision of the European Union (EU) for the next decade [l], involves advances in key areas such as sensors, interfaces, smart spaces, distributed and embedded computing technolo- gies, service intelligence, and security. Mobile communications technology, location technolo- gies, as well as new intelligent, adaptive, context- aware, and linked services can lead the first wave, since these technologies either are already mature or involve tractable problems. Context awareness in services is really about closely and properly linking services in such a way thatboth developers and users are relieved of submitting information that already exists in other parts of the global system. Interoperability issues can be efficiently dealt with through the standardization of well defined context data models and inter- faces. In this manner services are expected to act in a concerted mode, which adds substantially to user friendliness and automation throughout the whole knowledge lifecycle. State-of-the-art applications are usually associated with area-specific contextual infor- mation, traditionally treated in an isolated ad hoc manner. This has produced great overhead in all stages of application development and management, not to mention the restricting computational load imposed on the network and terminals, especially wireless thin clients. Reusable context handling components and efficiently distributed globally interoperable databases can significantly relieve the networks and improve the quality of service presented to , usem Bpth private and business users can ben- efit from a “one-stop shop” philosophy in con- text information provisioning, which would enable them to make their own context auto- matically available to any subscribed service. The context of a user-service combination can include information items like calendar, user location, weather, personal preferences, per- mission profiles, bther services offered to the same user, other users in the same area, and many others. Until recently, research projects were only able to deal effectively with one or two types of contextual information, such as IST projects VESPER (http://vesper.intranet.gr) and CELLO zy (http:/lwww.telecom.ntua.gr/cello/). The former focused on personal information handling for the provision of virtual home environment (VHE) services to roaming users, and the latter elaborated on the use of location information for advanced efficiency in network management. New IST projects, like CONTEXT (http://con- text.upc.es), are currently working on the inte- gration of multiple types of context and the design of an adequate methodology and a suit- able infrastructure to allow integration of multi- ple types of context in all stages of the service life cycle. An essential aspect of work in this direction is the adoption of an end-to-end 40 1536-1284/04/$20.00 zyxwvutsr 0 2004 IEEE IEEE Wireless Communications * April 2004