Future computing environments will free the user from the constraints of the desktop. Applications for a mobile environment should take advantage of contextual information, such as position, to offer greater services to the user. In this paper, we present the Cyberguide project, in which we are building prototypes of a mobile context-aware tour guide. Knowledge of the user's current location, as well as a history of past locations, are used to provide more of the kind of services that we come to expect from a real tour guide. We describe the architecture and features of a variety of Cyberguide prototypes developed for indoor and outdoor use on a number of different hand-held platforms. We also discuss the general research issues that have emerged in our context-aware applications development in a mobile environment.

Note: OCR errors may be found in this Reference List extracted from the full text article. ACM has opted to expose the complete List rather than only correct and linked references.

	1	G.D. Abowd, C.G. Atkeson, A. Feinstein, Y. Goolamabbas, C. Hmelo, S. Register, N.N. Sawhney and M. Tan, Classroom 2000 enhancing classroom interaction and review, Technical Report GIT- 96-21, Graphics, Visualization and Usability Center, Georgia Institute of Technology (September 1996).
	2	Gregory D. Abowd , Christopher G. Atkeson , Ami Feinstein , Cindy Hmelo , Rob Kooper , Sue Long , Nitin Sawhney , Mikiya Tani, Teaching and learning as multimedia authoring: the classroom 2000 project, Proceedings of the fourth ACM international conference on Multimedia, p.187-198, November 18-22, 1996, Boston, Massachusetts, United States  [doi>10.1145/244130.244191]
	3	A. Asthana, M. Cravatts and P. Krzyzanouski, An indoor wireless system for personalized shopping assistance, in: eds. L.-F. Cabrera and M. Sattyanarayanan, Workshop on Mobile Computing Systems and Applications (IEEE Computer Society Press, December 1994) pp. 69-74.
	4	J.F. Bartlett, W4 - the wireless World Wide Web, in: eds. L.-F. Cabrera and M. Sattyanarayanan, Workshop on Mobile Computing Sys-tems and Applications (IEEE Computer Society Press, December 1994) pp. 176-178.
	5	B. Krupczak, M. Ammar and K. Calvert, Multi-subsystem protocol architectures: Motivation and experience with an adaptor-based approach, in: Proceedings of IEEE INFOCOM '96 (1996).
	6	Sue Long , Rob Kooper , Gregory D. Abowd , Christopher G. Atkeson, Rapid prototyping of mobile context-aware applications: the Cyberguide case study, Proceedings of the 2nd annual international conference on Mobile computing and networking, p.97-107, November 1996, Rye, New York, United States  [doi>10.1145/236387.236412]
	7	Sue Long , Rob Kooper , Gregory D. Abowd , Christopher G. Atkeson, Rapid prototyping of mobile context-aware applications: the Cyberguide case study, Proceedings of the 2nd annual international conference on Mobile computing and networking, p.97-107, November 1996, Rye, New York, United States  [doi>10.1145/236387.236412]
	8	Allan Christian Long, Jr. , Shankar Narayanaswamy , Andrew Burstein , Richard Han , Ken Lutz , Brian Richards , Samuel Sheng , Robert W. Brodersen , Jan Rabaey, A prototype user interface for a mobile multimedia terminal, Conference companion on Human factors in computing systems, p.81-82, May 07-11, 1995, Denver, Colorado, United States  [doi>10.1145/223355.223439]
	9	Scott Minneman , Steve Harrison , Bill Janssen , Gordon Kurtenbach , Thomas Moran , Ian Smith , Bill van Melle, A confederation of tools for capturing and accessing collaborative activity, Proceedings of the third ACM international conference on Multimedia, p.523-534, November 05-09, 1995, San Francisco, California, United States  [doi>10.1145/217279.215316]
	10	Thomas P. Moran , Patrick Chiu , Steve Harrison , Gordon Kurtenbach , Scott Minneman , William van Melle, Evolutionary engagement in an ongoing collaborative work process: a case study, Proceedings of the 1996 ACM conference on Computer supported cooperative work, p.150-159, November 16-20, 1996, Boston, Massachusetts, United States  [doi>10.1145/240080.240243]
	11	H. Rheingold, Tools for Thought (Prentice-Hall, Englewood Cliffs, 1985).
	12	N.N. Sawhney, G.D. Abowd and C.G. Atkeson, Can electronic notebooks enhance the classroom? Technical Report GIT-96-06, Graphics, Visualization and Usability Center, Georgia Institute of Technology (February 1996).
	13	William Noah Schilit, A system architecture for context-aware mobile computing, Columbia University, New York, NY, 1995
	14	Roy Want , Andy Hopper , Veronica Falcão , Jonathan Gibbons, The active badge location system, ACM Transactions on Information Systems (TOIS), v.10 n.1, p.91-102, Jan. 1992  [doi>10.1145/128756.128759]
	15	R. Want, B. Schilit, N. Adams, R. Gold, K. Petersen, J. Ellis, D. Goldberg and M. Weiser, The PARCTAB ubiquitous computing experiment, Technical Report CSL-95-1, Xerox Palo Alto Research Center (March 1995).

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