Buffer management for a D-disk parallel I/O system is considered in the context of randomized placement of data on the disks. A simple prefetching and caching algorithm PHASE-LRU using bounded lookahead is described a...
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Buffer management for a D-disk parallel I/O system is considered in the context of randomized placement of data on the disks. A simple prefetching and caching algorithm PHASE-LRU using bounded lookahead is described and analyzed. It is shown that PHASE-LRU performs an expected number of I/Os that is within a factor Theta(log D/log log D) of the number performed by an optimal off-line algorithm. In contrast, any deterministic buffer management algorithm with the same amount of lookahead must do at least Omega(rootD) times the number of I/Os of the optimal. (C) 2004 Elsevier B.V. All rights reserved.
We develop a framework for quantitative convergence analysis of Picard iterations of expansive set-valued fixed point mappings. There are two key components of the analysis. The first is a natural generalization of si...
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We develop a framework for quantitative convergence analysis of Picard iterations of expansive set-valued fixed point mappings. There are two key components of the analysis. The first is a natural generalization of single-valued averaged mappings to expansive set-valued mappings that characterizes a type of strong calmness of the fixed point mapping. The second component to this analysis is an extension of the well-established notion of metric subregularity-or inverse calmness-of the mapping at fixed points. Convergence of expansive fixed point iterations is proved using these two properties, and quantitative estimates are a natural by-product of the framework. To demonstrate the application of the theory, we prove, for the first time, a number of results showing local linear convergence of nonconvex cyclic projections for inconsistent (and consistent) feasibility problems, local linear convergence of the forward-backward algorithm for structured optimization without convexity, strong or otherwise, and local linear convergence of the Douglas-Rachford algorithm for structured nonconvex minimization. This theory includes earlier approaches for known results, convex and nonconvex, as special cases.
The asymptotic analysis of a class of binomial sums that arise in information theory can be performed in a simple way by means of singularity analysis of generating functions. The method developed extends the range of...
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The asymptotic analysis of a class of binomial sums that arise in information theory can be performed in a simple way by means of singularity analysis of generating functions. The method developed extends the range of applicability of singularity analysis techniques to combinatorial sums involving transcendental elements like logarithms or fractional powers. (C) 1999-Elsevier Science B.V. All rights reserved.
We prove the worst-case upper bound 1.5045..(n) for the time complexity of 3-SAT decision, where n is the number of variables in the input formula, introducing new methods for the analysis as well as new algorithmic t...
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We prove the worst-case upper bound 1.5045..(n) for the time complexity of 3-SAT decision, where n is the number of variables in the input formula, introducing new methods for the analysis as well as new algorithmic techniques. We add new 2- and 3-clauses, called "blocked clauses", generalizing the extension rule of "Extended Resolution." Our methods for estimating the size of trees lead to a refined measure of formula complexity of 3-clause-sets and can be applied also to arbitrary trees. (C) 1999 Elsevier Science B.V. All rights reserved.
It is shown that the depth of the last node inserted in a random quad tree constructed from independent uniform [0,1]d<span style="display: inline-block
Given a set of n elements each of which is either red or blue, Boyer and Moore's MJRTY algorithm uses pairwise equal/not equal color comparisons to determine the majority color. We analyze the average behavior of ...
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Given a set of n elements each of which is either red or blue, Boyer and Moore's MJRTY algorithm uses pairwise equal/not equal color comparisons to determine the majority color. We analyze the average behavior of their algorithm, proving that if all 2(n) possible inputs are equally likely, the average number of color comparisons used is n - root 2n/pi + O(1) with variance (pi - 2)n/pi - root 2n/pi + O(1). (C) 2013 Elsevier B.V. All rights reserved.
A generalization of the particle swarm optimization (PSO) algorithm is presented in this paper. The novel optimizer, the Generalized PSO (GPSO), is inspired by linear control theory. It enables direct control over the...
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A generalization of the particle swarm optimization (PSO) algorithm is presented in this paper. The novel optimizer, the Generalized PSO (GPSO), is inspired by linear control theory. It enables direct control over the key aspects of particle dynamics during the optimization process. A detailed theoretical and empirical analysis is presented, and parameter-tuning schemes are proposed. GPSO is compared to the classical PSO and genetic algorithm (GA) on a set of benchmark problems. The results clearly demonstrate the effectiveness of the proposed algorithm. Finally, an application of the GPSO algorithm to the fine-tuning of the support vector machines classifier for electrical machines fault detection is presented. (C) 2011 Elsevier Inc. All rights reserved.
The average-case complexity of BIT algorithm, a version of move-to-front (MTF) algorithm, was analyzed. A theorem showed that the cost of BIT is asymptotically better than that of MTF. Another theorem verified that th...
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The average-case complexity of BIT algorithm, a version of move-to-front (MTF) algorithm, was analyzed. A theorem showed that the cost of BIT is asymptotically better than that of MTF. Another theorem verified that the overwork of BIT is at least 1.5 times that of MTF. A function was structured so as to determine values of length t for which BIT performs better than MTF given a sequence Z of requests, if L, the size of size n, is initialized at random.
An algorithm for the scheduling of events in a discrete-event simulation system, due to J. O. Henriksen, is presented. An O(n<span class="mn" id="MathJax-Span-11" style="font-size: 7
The result of birthday problem is of fundamental importance and has many applications in diverse areas, analyzing the discrete logarithm problem in particular. The birthday problem can be modeled as sampling balls wit...
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The result of birthday problem is of fundamental importance and has many applications in diverse areas, analyzing the discrete logarithm problem in particular. The birthday problem can be modeled as sampling balls with replacement until one is sampled twice. In the classical scenario, balls are sampled uniformly. Inspired by the analysis of algorithms solving certain discrete logarithms, Galbraith and Holmes considered the non-uniform birthday problem and gave an estimate on the number of sampling before having a collision up to the dominating term. In this paper, we give a refined analysis to the non-uniform birthday problem, and apply it to the analysis of an algorithm solving certain discrete logarithm problem. Experiment results suggest that parameter selection following this refined analysis performs better than related work. (C) 2021 Elsevier B.V. All rights reserved.
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