In this paper, we present two rate allocation algorithms for embedded motion compensated video coders. The algorithms are based on the modeling of both the video signal and the coder which allow us to express the codi...
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This paper describes a technique for making personalized recommendations from any type of database to a user based on similarities between the interest profile of that user and those of other users. In particular, we ...
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This paper describes a technique for making personalized recommendations from any type of database to a user based on similarities between the interest profile of that user and those of other users. In particular, we discuss the implementation of a networked system called Ringo, which makes personalized recommendations for music albums and artists. Ringo's database of users and artists grows dynamically as more people use the system and enter more information. Four different algorithms for making recommendations by using social information filtering were tested and compared. We present quantitative and qualitative results obtained from the use of Ringo by more than 2000 people.
We define a novel measure of competitive performance for distributed algorithms based on throughput, the number of tasks that an algorithm can carry out in a fixed amount of work. An important property of the throughp...
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ISBN:
(纸本)9780897917858
We define a novel measure of competitive performance for distributed algorithms based on throughput, the number of tasks that an algorithm can carry out in a fixed amount of work. An important property of the throughput measure is that it is modular: we define a notion of relative competitiveness with the property that a k-relatively competitive implementation of an object T using a subroutine U, combined with an l-competitive implementation of U, gives a kl-competitive algorithm for T. We prove the throughput-competitiveness of an algorithm for a fundamental building block of many well-known distributed algorithms: the cooperative collect primitive. This permits a straightforward construction of competitive versions of these algorithms - the first examples of algorithms obtained through a general method for modular construction of competitive distributed algorithms. Moreover, we provide a lower bound that shows that the throughput competitiveness of the cooperative collect algorithm we study is nearly optimal. Thus, we see our paper as making two main contributions: one is the introduction of a modular measurement for competitiveness, whose interest is justified by the throughput competitiveness of the cooperative collect algorithms;and the other is a technique for proving throughput competitiveness, which may apply to other distributed problems.
The Incremental backprojection algorithm is a fast backprojection approach requiring only O(N) and O (N2) multiplications in contrast to O(N2) and O(N3) multiplications for the Shepp and Logan's backprojection alg...
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The Incremental backprojection algorithm is a fast backprojection approach requiring only O(N) and O (N2) multiplications in contrast to O(N2) and O(N3) multiplications for the Shepp and Logan's backprojection algorithm in 2D and 3D backprojections, respectively, for each view. However, the improvement achieved by the Incremental algorithm in practice was not so significant as expected in theory due to inevitably visiting pixels outside the beam in the searching flow scheme originally developed for the Incremental algorithm. To optimize implementation of the Incremental algorithm, an efficient scheme, namely, coded searching flow scheme, is proposed in this paper to minimize the overhead caused by searching for all pixels in a beam. The key idea of this scheme is to encode the searching flow for all pixels inside each beam. While backprojection, all pixels may be visited without any overhead due to using the coded searching flow as the a priori information. The proposed coded searching flow scheme has been implemented on a Sun Sparc 10 and a Sun Sparc 20 workstations. The implementation results show that the proposed scheme is 1.45-2.0 times faster than the original searching flow scheme for most cases tested. Compared to the conventional Shepp and Logan's backprojection algorithm, the proposed scheme may achieve 5-8 and 3 times speed-ups for 2D and 3D backprojection, respectively.
The study aims to suppress the transient and nonstationary high-SPL (sound pressure level) shock noise. A full-size acrylic model is built up for mimicking the sound field of the control room of a rocket-launching veh...
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Chordal graphs are nothing else than intersection graphs of subtrees of a tree. We present optimal and almost algorithms for certain graph problems if the input graph is given by a collection of subtrees of a tree and...
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ISBN:
(纸本)0818650605
Chordal graphs are nothing else than intersection graphs of subtrees of a tree. We present optimal and almost algorithms for certain graph problems if the input graph is given by a collection of subtrees of a tree and the subtrees are given by their leaves. This generalizes results of Olariu, Schwing, and Zhang, Kim, and Chen concerning the parallel complexity of problems on interval graphs provided the interval structure is given. In particular, we consider the problems to find a breadth-first search tree, to find a depth-first search tree, to find a minimum covering of the vertices by cliques, and to find a minimum coloring.
In this article three new estimators of the frequency of a single complex sinusoid are presented. The "rotate-add-decimate" (RAD) method of Crozier is first modified to more closely approach the Cramer-Rao B...
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This article describes the traditional algorithms of determinist an statistic clusterification and classification (a priori and with learning), by comparing the results obtained using the classifiers based on neural n...
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This article describes the traditional algorithms of determinist an statistic clusterification and classification (a priori and with learning), by comparing the results obtained using the classifiers based on neural networking techniques in supervised learning (Multi-layer perceptron with Backpropagation). The selected samples, chosen to check the algorithms have been marble slabs of 'Sierra de la Puerta' type.
This paper introduces RoxyBot, one of the top-scoring agents in the First International Trading Agent Competition. A TAG agent simulates one vision of future travel agents: it represents a set of clients in simultaneo...
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ISBN:
(纸本)9781581133875
This paper introduces RoxyBot, one of the top-scoring agents in the First International Trading Agent Competition. A TAG agent simulates one vision of future travel agents: it represents a set of clients in simultaneous auctions, trading complementary (e.g., airline tickets and hotel reservations) and substitutable (e.g., symphony and theater tickets) goods. RoxyBot faced two key technical challenges in TAG: (i) allocation-assigning purchased goods to clients at the end of a game instance so as to maximize total client utility, and (ii) completion-determining the optimal quantity of each resource to buy and sell given client preferences, current holdings, and market prices. For the dimensions of TAG, an optimal solution to the allocation problem is tractable, and RoxyBot uses a search algorithm based on *** to produce optimal allocations. An optimal solution to the completion problem is also tractable, but in the interest of minimizing bidding cycle time, RoxyBot solves the completion problem using beam search, producing approximately optimal completions. RoxyBot's completer relies on an innovative data structure called a priceline.
We present two polynomial-time approximation algorithms for the metric case of the maximum traveling salesman problem. One of them is for directed graphs and its approximation ratio is 27/35. The other is for undirect...
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