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Articles 1 - 9 of 9
Full-Text Articles in Physical Sciences and Mathematics
Bayes Optimal Metasearch: A Probabilistic Model For Combining The Results Of Multiple Retrieval Systems, Javed A. Aslam, Mark Montague
Bayes Optimal Metasearch: A Probabilistic Model For Combining The Results Of Multiple Retrieval Systems, Javed A. Aslam, Mark Montague
Computer Science Technical Reports
We introduce a new, probabilistic model for combining the outputs of an arbitrary number of query retrieval systems. By gathering simple statistics on the average performance of a given set of query retrieval systems, we construct a Bayes optimal mechanism for combining the outputs of these systems. Our construction yields a metasearch strategy whose empirical performance nearly always exceeds the performance of any of the constituent systems. Our construction is also robust in the sense that if ``good'' and ``bad'' systems are combined, the performance of the composite is still on par with, or exceeds, that of the best constituent …
Reconstructing Ancient Egyptian Tombs, Hany Farid
Reconstructing Ancient Egyptian Tombs, Hany Farid
Computer Science Technical Reports
From the pyramids of Giza to the tombs of Thebes (modern Luxor), ancient Egypt's glorious history has produced remarkable architecture. Sadly, the nearly four million yearly tourists have taken a heavy toll on many of these ancient structures. Of particular concern are many of the tombs located opposite to Luxor on the western bank of the Nile. Digital reconstruction of these tombs has the potential to help document and preserve these important historical structures. Photographing and reconstruction of these tombs poses new and unique problems that this paper begins to address. Techniques for removing image distortions, recovering 3-D shape, and …
A Survey Of Context-Aware Mobile Computing Research, Guanling Chen, David Kotz
A Survey Of Context-Aware Mobile Computing Research, Guanling Chen, David Kotz
Computer Science Technical Reports
Context-aware computing is a mobile computing paradigm in which applications can discover and take advantage of contextual information (such as user location, time of day, nearby people and devices, and user activity). Since it was proposed about a decade ago, many researchers have studied this topic and built several context-aware applications to demonstrate the usefulness of this new technology. Context-aware applications (or the system infrastructure to support them), however, have never been widely available to everyday users. In this survey of research on context-aware systems and applications, we looked in depth at the types of context used and models of …
Performance Analysis Of Mobile Agents For Filtering Data Streams On Wireless Networks, David Kotz, George Cybenko, Robert S. Gray, Guofei Jiang, Ronald A. Peterson, Martin O. Hofmann, Daria A. Chacon, Kenneth R. Whitebread
Performance Analysis Of Mobile Agents For Filtering Data Streams On Wireless Networks, David Kotz, George Cybenko, Robert S. Gray, Guofei Jiang, Ronald A. Peterson, Martin O. Hofmann, Daria A. Chacon, Kenneth R. Whitebread
Computer Science Technical Reports
Wireless networks are an ideal environment for mobile agents, since their mobility allows them to move across an unreliable link to reside on a wired host, next to or closer to the resources that they need to use. Furthermore, client-specific data transformations can be moved across the wireless link and run on a wired gateway server, reducing bandwidth demands. In this paper we examine the tradeoffs faced when deciding whether to use mobile agents in a data-filtering application where numerous wireless clients filter information from a large data stream arriving across the wired network. We develop an analytical model and …
The Complexity Of Planning With Partially-Observable Markov Decision Processes, Martin Mundhenk
The Complexity Of Planning With Partially-Observable Markov Decision Processes, Martin Mundhenk
Computer Science Technical Reports
This work surveys results on the complexity of planning under uncertainty. The planning model considered is the partially-observable Markov decision process. The general planning problems are, given such a process, (a) to calculate its performance under a given control policy, (b) to find an optimal or approximate optimal control policy, and (c) to decide whether a good policy exists. The complexity of this and related problems depend on a variety of factors, including the observability of the process state, the compactness of the process representation, the type of policy, or even the number of actions relative to the number of …
Approximation Algorithms For The Minimum Bends Traveling Salesman Problem, Cliff Stein, David P. Wagner
Approximation Algorithms For The Minimum Bends Traveling Salesman Problem, Cliff Stein, David P. Wagner
Computer Science Technical Reports
The problem of traversing a set of points in the order that minimizes the total distance traveled (traveling salesman problem) is one of the most famous and well-studied problems in combinatorial optimization. It has many applications, and has been a testbed for many of the must useful ideas in algorithm design and analysis. The usual metric, minimizing the total distance traveled, is an important one, but many other metrics are of interest. In this paper, we introduce the metric of minimizing the number of turns in the tour, given that the input points are in the Euclidean plane. To our …
Performance Analysis Of Mobile Agents For Filtering Data Streams On Wireless Networks, David Kotz, Guofei Jiang, Robert Gray, George Cybenko, Ronald A. Peterson
Performance Analysis Of Mobile Agents For Filtering Data Streams On Wireless Networks, David Kotz, Guofei Jiang, Robert Gray, George Cybenko, Ronald A. Peterson
Computer Science Technical Reports
Wireless networks are an ideal environment for mobile agents, because their mobility allows them to move across an unreliable link to reside on a wired host, next to or closer to the resources they need to use. Furthermore, client-specific data transformations can be moved across the wireless link, and run on a wired gateway server, with the goal of reducing bandwidth demands. In this paper we examine the tradeoffs faced when deciding whether to use mobile agents to support a data-filtering application, in which numerous wireless clients filter information from a large data stream arriving across the wired network. We …
A Formal Semantics For Spki, Jon Howell, David Kotz
A Formal Semantics For Spki, Jon Howell, David Kotz
Computer Science Technical Reports
We extend the logic and semantics of authorization due to Abadi, Lampson, et al. to support restricted delegation. Our formal model provides a simple interpretation for the variety of constructs in the Simple Public Key Infrastructure (SPKI), and lends intuition about possible extensions. We discuss both extensions that our semantics supports and extensions that it cautions against.
Landmarks For Absolute Localization, Jon Howell, Keith Kotay
Landmarks For Absolute Localization, Jon Howell, Keith Kotay
Computer Science Technical Reports
For certain experiments in mobile robotics, it is convenient to eliminate positional estimation error in the interest of analyzing other parts of the experiment. We designed and implemented a simple, accurate scheme for encoding and recovering absolute position information. The encoding is a two-dimensional image printed on the plane of the floor, and the absolute position information is recovered using a downward-looking video camera mounted on a mobile robot.