We consider the one-dimensional bin packing problem and analyze the averagecase performance of bounded space algorithms. The analysis covers a wide variety of bin packing algorithms including Next-K Fit, K-Bounded Be...
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We consider the one-dimensional bin packing problem and analyze the averagecase performance of bounded space algorithms. The analysis covers a wide variety of bin packing algorithms including Next-K Fit, K-Bounded Best Fit and Harmonic algorithms, as well as of others. We assume discrete item sizes, an assumption which is true in most real-world applications of bin packing. We present a Markov chains method which is general enough to calculate results for any i.i.d. discrete item size distribution. The paper presents many results heretofore unknown or conjectured from simulation. Some of the results are surprising as they differ considerably from results for continuous distributions.
We maintain the maximum spanning tree of a planar point set, as points are inserted or deleted, in O(log(3) n) expected time per update in Mulmuley's average-case model of dynamic geometric computation. We use as ...
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We maintain the maximum spanning tree of a planar point set, as points are inserted or deleted, in O(log(3) n) expected time per update in Mulmuley's average-case model of dynamic geometric computation. We use as subroutines dynamic algorithms for two other geometric graphs: the farthest neighbor forest and the rotating caliper graph related to an algorithm for static computation of point set widths and diameters. We maintain the former graph in expected time O(log(2) n) per update and the latter in expected time O(log n) per update. We also use the rotating caliper graph to maintain the diameter, width,, and minimum enclosing rectangle of a point set in expected time O(logn) per update. A subproblem uses a technique for average-case orthogonal range search that may also be of interest.
We study how to label the vertices of a tree in such a way that we can decide the distance of two vertices in the tree given only their labels. Gavoille et al. proved that for any such distance labelling scheme, the m...
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We study how to label the vertices of a tree in such a way that we can decide the distance of two vertices in the tree given only their labels. Gavoille et al. proved that for any such distance labelling scheme, the maximum label length is at least 1/8 log(2) n - O (log n) bits, where n is the number of vertices in the input tree T. They also gave a separator-based labelling scheme 8 that has the optimal label length Theta (log n center dot log(H-n (T))), where H-n (T) is the height of T. We present two distance labelling schemes, namely, the backbone-based scheme and rake-based scheme, which also achieve the optimal label length. The two schemes always perform at least as well as the separator scheme. Furthermore, the rake-based scheme has a much smaller expected label length under certain tree distributions. With these new schemes, we also can find the least common ancestor of any two vertices based on their labels only. (c) 2007 Elsevier B.V. All rights reserved.
Sreedhar et al. [V.C. Sreedhar, G.R. Gao, Y.-F. Lee, A new framework for elimination-based data flow analysis using DJ graphs, ACM Trans. Program. Lang. Syst. 20 (2) (1998) 388-435;V.C. Sreedhar, Efficient program ana...
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Sreedhar et al. [V.C. Sreedhar, G.R. Gao, Y.-F. Lee, A new framework for elimination-based data flow analysis using DJ graphs, ACM Trans. Program. Lang. Syst. 20 (2) (1998) 388-435;V.C. Sreedhar, Efficient program analysis using DJ graphs, PhD thesis, School of Computer Science, McGill University, Montreal, Quebec, Canada, 1995] have presented an elimination-based algorithm to solve data flow problems. A thorough analysis of the algorithm shows that the worst-case performance is at least quadratic in the number of nodes of the underlying graph. In contrast, Sreedhar reports a linear time behavior based on some practical applications. In this paper we prove that for goto-free programs, the averagecase behavior is indeed linear. As a byproduct our result also applies to the average size of the so-called dominance frontier. A thorough average case analysis based on a graph grammar is performed by studying properties of the j-edges in DJ graphs. It appears that this is the first time that a graph grammar is used in order to analyze an algorithm. The average linear time of the algorithm is obtained by classic techniques in the analysis of algorithms and data structures such as singularity analysis of generating functions and transfer lemmas. (C) 2005 Elsevier B.V. All rights reserved.
This paper gives the average distance analysis for the Euclidean tree constructed by a simple greedy but efficient algorithm of the on-line Steiner tree problem. The algorithm accepts the data one by one following the...
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This paper gives the average distance analysis for the Euclidean tree constructed by a simple greedy but efficient algorithm of the on-line Steiner tree problem. The algorithm accepts the data one by one following the order of input sequence. When a point arrives, the algorithm adds the shortest edge, between the new point and the points arriving already, to the previously constructed tree to form a new tree. We first show that, given n points uniformly on a unit disk in the plane, the expected Euclidean distance between a point and its j(th) (1 less than or equal to j less than or equal to n - 1) nearest neighbor is less than or equal to (5/3)root/j/n when n is large. Based upon this result, we show that the expected length of the tree constructed by the on-line algorithm is not greater than 4.34 times the expected length of the minimum Steiner tree when the number of input points is large.
We study how to label the vertices of a tree in such a way that we can decide the distance of two vertices in the tree given only their labels. Gavoille et al. proved that for any such distance labelling scheme, the m...
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ISBN:
(纸本)3540309357
We study how to label the vertices of a tree in such a way that we can decide the distance of two vertices in the tree given only their labels. Gavoille et al. proved that for any such distance labelling scheme, the maximum label length is at least 1/8 log(2) n - O (log n) bits, where n is the number of vertices in the input tree T. They also gave a separator-based labelling scheme 8 that has the optimal label length Theta (log n center dot log(H-n (T))), where H-n (T) is the height of T. We present two distance labelling schemes, namely, the backbone-based scheme and rake-based scheme, which also achieve the optimal label length. The two schemes always perform at least as well as the separator scheme. Furthermore, the rake-based scheme has a much smaller expected label length under certain tree distributions. With these new schemes, we also can find the least common ancestor of any two vertices based on their labels only. (c) 2007 Elsevier B.V. All rights reserved.
Compressive multichannel frequency estimation refers to the process of retrieving the frequency profile shared by multiple signals from their compressive samples. A recent approach to this problem relies on atomic nor...
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ISBN:
(纸本)9781538668122;9781538668115
Compressive multichannel frequency estimation refers to the process of retrieving the frequency profile shared by multiple signals from their compressive samples. A recent approach to this problem relies on atomic norm minimization which exploits joint sparsity among the channels, is solved using convex optimization, and has strong theoretical guarantees. We provide in this paper an average-caseanalysis for atomic norm minimization by assuming proper randomness on the amplitudes of the frequencies. We show that the sample size per channel required for exact frequency estimation from noiseless samples decreases as the number of channels increases and is on the order of K log K (1 + 1/L log N), where K is the number of frequencies, L is the number of channels, and N is a fixed parameter proportional to the sampling window size and inversely proportional to the desired resolution.
In this paper we study some relevant prefixes of coloured Motzkin walks (otherwise called coloured Motzkin words). In these walks, the three kinds of step can have alpha, beta and gamma colours, respectively. In parti...
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In this paper we study some relevant prefixes of coloured Motzkin walks (otherwise called coloured Motzkin words). In these walks, the three kinds of step can have alpha, beta and gamma colours, respectively. In particular, when alpha = beta = gamma = 1 we have the classical Motzkin walks while for alpha = gamma = 1 and beta = 0 we find the well-known Dyck walks. By using the concept of Riordan arrays and probability generating functions we find the average length of the relevant prefix in a walk of length n and the corresponding variance in terms of alpha, beta and gamma. This result is interesting from a combinatorial point of view and also provides an average case analysis of algorithms related to the problem of ranking and generating uniformly at random the coloured Motzkin words. (C) 2009 Elsevier B.V. All rights reserved.
We present a new average case analysis for the problem of scheduling n jobs on m machines so that the sum of job completion times is minimized. Our goal is to use the concept of competitive ratio-which is a typical wo...
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We present a new average case analysis for the problem of scheduling n jobs on m machines so that the sum of job completion times is minimized. Our goal is to use the concept of competitive ratio-which is a typical worst case notion-also within an average case analysis. We show that the classic SEPT scheduling strategy with 0(n) worst-case competitive ratio achieves an average of 0(l) under several natural distributions, among them the exponential distribution. Our analysis technique allows to also roughly estimate the probability distribution of the competitive ratio. Thus, Our result bridges the gap between worst case and averagecase performance guarantee.
We present an average case analysis of the minimum spanning tree heuristic for the power assignment problem. The worst-case approximation ratio of this heuristic is 2. We show that in Euclidean d-dimensional space, wh...
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We present an average case analysis of the minimum spanning tree heuristic for the power assignment problem. The worst-case approximation ratio of this heuristic is 2. We show that in Euclidean d-dimensional space, when the vertex set consists of a set of i.i.d. uniform random independent, identically distributed random variables in [0,1](d), and the distance power gradient equals the dimension d, the minimum spanning tree-based power assignment converges completely to a constant depending only on d.
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