Abstract
Mobile computing represents a major point of departure from the traditional distributed-computing paradigm. The potentially very large number of independent computing units, a decoupled computing style, frequent disconnections, continuous position changes, and the location-dependent nature of the behavior and communication patterns present designers with unprecedented challenges in the areas of modularity and dependability. So far, the literature on mobile computing is dominated by concerns having to de with the development of protocols and services. This article complements this perspective by considering the nature of the underlying formal models that will enable us to specify and reason about such computations. The basic research goal is to characterize fundamental issues facing mobile computing. We want to achieve this in a manner analogous to the way concepts such as shared variables and message passing help us understand distributed computing. The pragmatic objective is to develop techniques that facilitate the verification and design of dependable mobile systems. Toward this goal we employ the methods of UNITY. To focus on what is essential, we center our study on ad hoc networks, whose singular nature is bound to reveal the ultimate impact of movement on the way one computes and communicates in a mobile environment. To understand interactions we start with the UNITY concepts of union and superposition and consider direct generalizations to transient interactions. The motivation behind the transient nature of the interactions comes from the fact that components can communicate with each other only when they are within a a certain range. The notation we employ is a highly modular extension of the UNITY programming notation. Reasoning about mobile computations relies on extensions to the UNITY proof logic.
- ABADI, M. AND LAMPORT, L. 1991. An old-fashioned recipe for real-time. In Lecture Notes in Computer Science, J. W. de Bakker, C. Huizing, W. P. Roever, and G. Rosenberg, Eds. Vol. 600. Springer-Verlag, Berlin, 1-27. Google Scholar
- BADRINATH, B. R. AND WELLING, G. 1995. Event delivery abstractions for mobile computing. Tech. Rep. LCSR-TR-242, Rutgers Univ., New Brunswick, N.J.Google Scholar
- CHANDY, K. M. AND MISRA, J. 1988. Parallel Program Design: A Foundation. Addison- Wesley, Reading, Mass. Google Scholar
- CLINGER, W.D. 1981. Foundations of actor semantics. Tech. Rep. AI-TR-633, MIT Artificial Intelligence Laboratory, MIT, Cambridge, Mass. Google Scholar
- JOHNSON, D.B. 1994. Routing in ad hoc networks of mobile hosts. In Proceedings of the Workshop on Mobile Computing Systems and Applications. IEEE Computer Society Press, Los Alamitos, Calif., 158-163.Google Scholar
- LAMPORT, L. 1994. The temporal logic of actions. ACM Trans. Program. Lang. Syst. 16, 3 (May), 872-923. Google Scholar
- MILNER, R., FARROW, J., AND WALKER, D. 1992. A calculus of mobile processes. I. Inf. Comput. 100, 1, 1-40. Google Scholar
- MISRA, J. 1995. A logic for concurrent programming: Safety. J. Comput. Softw. Eng. 3, 2, 239-272.Google Scholar
- NOBLE, B. D., PRICE, M., AND SATYANARAYANAN, M. 1995. A programming interface for application-aware adaptation in mobile computing. Comput. Syst. 8, 4, 345-363.Google Scholar
- PERKINS, C. 1996. IP mobility support. Internet Draft Draft-IETF-Mobileip-16. Internet Engineering Task Force, Reston, Va. Available as ftp://ftp.ietf.cnri.reston.va.us/internetdrafts/draft-ietf-mobileip-protocol-16-txt.Google Scholar
- ROMAN, G.-C. AND CUNNINGHAM, H. C. 1992. Reasoning about synchronic groups. In Research Directions in High-Level Parallel Programming Languages, J. P. Ban~tre and D. L. Metayer, Eds. Lecture Notes in Computer Science, vol. 574. Springer-Verlag, Berlin, 21-38. Google Scholar
- ROMAN, G.-C., PLUN, J. Y., AND WILCOX, C. D. 1993. Dynamic synchrony among atomic actions. IEEE Trans. Parallel Distrib. Syst. 4, 6, 677-685. Google Scholar
- SATYANARAYANAN, M., KISTLER, J. J., MUMMERT, L. B., EBLING, M. R., KUMAR, P., AND LU, Q. 1993. Experience with disconnected operation in a mobile computing environment. In Proceedings of the USENIX Symposium on Mobile and Location-Independent Computing. USENIX Assoc., Berkeley, Calif., 11-28.Google Scholar
- SCHILIT, B. N., ADAMS, N., AND WANT, R. 1994. Context-aware computing applications. In Proceedings of the Workshop on Mobile Computing Systems and Applications. IEEE Computer Society Press, Los Alamitos, Calif., 85-90.Google Scholar
- TAIT, C. D. AND DUCHAMP, D. 1992. An efficient variable consistency replicated file service. In Proceedings of the USENIX File Systems Workshop. USENIX Assoc., Berkeley, Calif., 111-126.Google Scholar
- TERRY, D., THEIMER, M., PETERSEN, K., DEMERS, A., SPREITZER, M., AND HAUSER, C. 1995. Managing update conflicts in Bayou, a weakly connected replicated storage system. Oper. Syst. Rev. 29, 5, 172-183. Google Scholar
- VOELKER, G. M. AND BERSHAD, B.N. 1994. Mobisaic: An information system for a mobile wireless computing environment. In Proceedings of the Workshop on Mobile Computing Systems and Applications. IEEE Computer Society Press, Los Alamitos, Calif., 185-190.Google Scholar
Index Terms
- Mobile UNITY: reasoning and specification in mobile computing
Recommendations
Modeling mobile IP in mobile UNITY
With recent advances in wireless communication technology, mobile computing is an increasingly important area of research. A mobile system is one where independently executing components may migrate through some space during the course of the ...
A Notation and Logic for Mobile Computing
We define a concurrent mobile system as one where independently executing components may migrate through some space during the course of the computation, and where the pattern of connectivity among the components changes as they move in and out of ...
Compositional Programming Abstractions for Mobile Computing
Recent advances in wireless networking technology and the increasing demand for ubiquitous, mobile connectivity demonstrate the importance of providing reliable systems for managing reconfiguration and disconnection of components. Design of such systems ...
Comments