Mobile computing environments that seek to support communication-intensive applications need to provide sustained end-to-end networking resources to static and mobile ows in the presence of scarce and variable wireless bandwidth, bursty wireless channel error, and user mobility. In order to achieve this goal, we present the TIMELY adaptive resource management architecture and algorithms for resource reservation, advance reservation, and network layer and end-to-end adaptation in mobile computing environments. The key novelty of our approach is the coordination of adaptation between the di erent layers of the network in order to solve the problems introduced by scarce and dynamic network resources.

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In this paper, we propose a novel approach for effectively supporting multimedia packet flows in an Internet environment. The following are the key contributions of this paper: (a) we propose a new transport protocol called HPF that supports multiple interleaved reliable and unreliable data sub-streams, (b) we decouple the congestion control and reliability mechanisms that are integrated in TCP -this allows us to provide congestion control for unreliable streams as well as reliable streams, and (c) we use priorities within sub-streams of a packet flow as application-defined hints for the link level scheduler to drop packets during congestion.We show through performance measurements in our experimental testbed that our approach can provide effective support for heterogeneous packet flows in the presence of dynamic networking resources.

The advent of affordable off-the-shelf wide-area wireless networking solutions for portable computers will result in partial (or intermittent) connectivity becoming the common networking mode for mobile users. This paper presents the design of PFS, a mobility-aware file system specially designed for partially connected operation.PFS supports the extreme modes of full connection and disconnection gracefully, but unlike other mobile file systems, it also provides an interrace for mobility-aware applications to direct the file system in its caching and consistency decisions in order to fully exploit intermittent connectivity. Using PFS, it is possible for an application to maintain consistency on only the critical portions of its data files. Since PFS provides adaptation at the file system level, even unaware applications can 'act' mobile-aware as a result of the transparent adaptation provided by PFS.

A new software package is described for graphically and analytically demonstrating the steady-state behavior of polyphase machines under a wide variety of operating conditions. Implemented in the C language, the interactive program employs sophisticated screen color graphics to show the slow-motion progression of the appropriate voltage or current waves, the loci of the resulting magnetic fields, and the movement of the machine rotor.It can be used to dynamically illustrate revolving-field concepts, the use of symmetrical components, and the effects of synchronous-machine torque angle and induction-machine slip. Screen movement can be frozen and significant numerical values displayed at any point during program use. The user may specify stator voltages or currents with any degree of unbalance. The neutral connection is arbitrary and can be altered during program execution. Input data (stored in text files) may be specified or altered interactively.The program is completely menu-driven and interactive, and contains appropriate help commands and instructions which enable it to be used without additional documentation. Some uses include classroom and laboratory demonstration, solution of student assignments, and refresher training in machine fundamentals.