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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)
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)
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)
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&amp;T WaveLAN, a popular(More)
1 Introduction There are considerable efforts within the Grid and high performance computing communities to improve end-to-end network performance for applications that require substantial amounts of network bandwidth. The Atlas project [19] for example, must be able to reliably transfer over 2 Petabytes of data per year over transatlantic networks from(More)
This position paper argues that the operating system and applications currently running on a real machine should relocate into a virtual machine. This structure enables services to be added below the operating system and to do so without trusting or modifying the operating system or applications. To demonstrate the usefulness of this structure , we describe(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)