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In this paper we show that application-aware adaptation, a collaborative partnership between the operating system and applications, offers the most general and effective approach to mobile information access. We describe the design of Odyssey, a prototype implementing this approach, and show how it supports concurrent execution of diverse mobile(More)
The loss behavior of wireless networks has become the focus of many recent research efforts. Although it is generally agreed that wireless communications experience higher error rates than wireline, the nature of these lossy links is not fully understood. This paper describes an effort to characterize the loss behavior of the AT&T WaveLAN, a popular(More)
This paper presents Virgil, an automatic access point discovery and selection system. Unlike existing systems that select access points based entirely on received signal strength, Virgil scans for all available APs at a location, quickly associates to each, and runs a battery of tests to estimate the quality of each AP's connection to the Internet. Virgil(More)
Backup is cumbersome and expensive. Individual users almost never back up their data, and backup is a significant cost in large organizations. This paper presents <i>Pastiche</i>, a simple and inexpensive backup system. Pastiche exploits excess disk capacity to perform peer-to-peer backup with no administrative costs. Each node minimizes storage overhead by(More)
This paper examines the effects of using parallel TCP flows to improve end-to-end network performance for distributed data intensive applications. A series of transmission experiments were conducted over a wide-area network to assess how parallel flows improve throughput, and to understand the number of flows necessary to improve throughput while avoiding(More)
Mobile systems must adapt their behavior to changing network conditions. To do this, they must accurately estimate available network capacity. Producing quality estimates is challenging because network observations are noisy, particularly in mobile, ad hoc networks. Current systems depend on simple, exponentially-weighted moving average (EWMA) filters.(More)
Simulation has become an indispensable tool in the construction and evaluation of mobile systems. By using <i>mobility models</i> that describe constituent movement, one can explore large systems, producing repeatable results for comparison between alternatives. Unfortunately, the vast majority of mobility models---including all those in which nodal speed(More)