String inclusion and non-inclusion problems have been vigorously studied in such diverse fields as molecular biology, data compression, and computer security. Among the well-known string inclusion or non-inclusion not...
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String inclusion and non-inclusion problems have been vigorously studied in such diverse fields as molecular biology, data compression, and computer security. Among the well-known string inclusion or non-inclusion notions, we are interested in the longest common nonsuperstring. Given a set of strings, the longest common nonsuperstring problem is finding the longest string that is not a superstring of any string in the given set. It is known that the longest common nonsuperstring problem is solvable in polynomial time. In this paper, we propose an efficient algorithm for the longest common nonsuperstring problem. The running time of our algorithm is linear with respect to the sum of the lengths of the strings in the given set, using generalized suffix trees. (C) 2009 Elsevier B.V. All rights reserved.
The k-center problem with triangle inequality is that of placing k center nodes in a weighted undirected graph in which the edge weights obey the triangle inequality, so that the maximum distance of any node to its ne...
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The k-center problem with triangle inequality is that of placing k center nodes in a weighted undirected graph in which the edge weights obey the triangle inequality, so that the maximum distance of any node to its nearest center is minimized. In this paper, we consider a generalization of this problem where, given a number p, we wish to place k centers so as to minimize the maximum distance of any non-center node to its pth closest center. We derive a best possible approximation algorithm for this problem. (C) 1998 Elsevier Science B.V.
Consider a probabilistic graph in which the edges are perfectly reliable, but vertices can fail with some known probabilities. The K-terminal reliability of this graph is the probability that a given set of vertices K...
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Consider a probabilistic graph in which the edges are perfectly reliable, but vertices can fail with some known probabilities. The K-terminal reliability of this graph is the probability that a given set of vertices K is connected. This reliability problem is #P-complete for general graphs, and remains #P-complete for chordal graphs and comparability graphs. This paper presents a linear-time algorithm for computing K-terminal reliability on proper interval graphs. A graph G = (V, E) is a proper interval graph if there exists a mapping from V to a class of intervals I of the real line with the properties that two vertices in G are adjacent if their corresponding intervals overlap and no interval in I properly contains another. This algorithm can be implemented in O(\V\ + \E\) time.
Since the initial paper of Hoffmann and O'Donnell [J. ACM 29 (1) (1982) 68-95], tree pattern matching has been studied by many authors. However, all the papers proposing algorithms for this problem deal with a res...
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Since the initial paper of Hoffmann and O'Donnell [J. ACM 29 (1) (1982) 68-95], tree pattern matching has been studied by many authors. However, all the papers proposing algorithms for this problem deal with a restricted notion of pattern occurrence in the subject. In this note, we consider a more general notion of occurrence and we give an extension of the top-down algorithm of Hoffmann and O'Donnell for this notion. (C) 2001 Elsevier Science B.V. All rights reserved.
The effect of a minimum spanning tree on finding the most vital edge in a network is addressed. Two algorithms are presented and their time complexities are determined.
The effect of a minimum spanning tree on finding the most vital edge in a network is addressed. Two algorithms are presented and their time complexities are determined.
In this paper we study a particular type of vehicle routing problem that arises in the context of scheduling an automatic guided vehicle (AGV) in the Flexible Manufacturing paradigm. Here we consider the problem of sc...
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In this paper we study a particular type of vehicle routing problem that arises in the context of scheduling an automatic guided vehicle (AGV) in the Flexible Manufacturing paradigm. Here we consider the problem of scheduling the vehicle when the sites are located on a path and the depot is at some arbitrary location. The objective is to determine the schedule with minimum completion time such that each site is visited only after its release time and handling times are taken into consideration. We provide a 5/3-approximation algorithm for the same. This improves the previous approximation ratio of 2 due to Karuno, Nagamochi and Ibaraki [Ann. Oper. Res. 69 (1997) 193-207]. (C) 2002 Elsevier Science B.V. All rights reserved.
Least median of squares (LMS) regression is a robust method to fit equations to observed data (typically in a linear model). This paper describes an approximation algorithm for LMS regression. The algorithm generates ...
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Least median of squares (LMS) regression is a robust method to fit equations to observed data (typically in a linear model). This paper describes an approximation algorithm for LMS regression. The algorithm generates a regression solution with median residual no more than twice the optimal median residual. Random sampling is used to provide a simple O(n log(2) n) expected time algorithm in the two-dimensional case that is successful with high probability. This algorithm is also extended to arbitrary dimension d with O(n(d-1) log n) worst-case complexity for fixed d > 2. (C) 1997 Elsevier Science B.V.
Hypercubes are attractive for interconnection in MIMD systems since many other types of interconnection networks can be embedded in them. In this note we study the embedding of complete binary trees in such a way that...
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Hypercubes are attractive for interconnection in MIMD systems since many other types of interconnection networks can be embedded in them. In this note we study the embedding of complete binary trees in such a way that an edge in the tree corresponds to an edge in the hypercube and show that a complete tree of height h can be embedded in this way into a d-dimensional hypercube if and only if d greater than or approximate to h + 2.
Let S be a set of elements. We say that a collection C of subsets of S has the consecutive ones property if there exist a linear order on S and a 0-1 matrix M, where M-ij = 1 if and only if the jth element is in the i...
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Let S be a set of elements. We say that a collection C of subsets of S has the consecutive ones property if there exist a linear order on S and a 0-1 matrix M, where M-ij = 1 if and only if the jth element is in the ith set in C. such that all l's appear consecutively in each row of M. A set X is an element of C is hit by a subset S' subset of S if X boolean AND S' not equal 0. Let C-r (red collection) and C-b (blue collection) be two collections of subsets of S respectively. The red-blue hitting set problem asks for a subset S' subset of S such that all sets in the blue collection are hit by S', while the number of sets in the red collection hit by S' has to be minimum. We present a shortest-path based algorithm with time complexity O(vertical bar C-b parallel to S vertical bar + vertical bar C-r parallel to S vertical bar + vertical bar S vertical bar(2)) for this problem with C-r boolean OR C-b having the consecutive ones property, which improves the previous time bound O(vertical bar C-r parallel to C-b parallel to S vertical bar(2)) by Dom et al. (2008) [8]. (C) 2010 Elsevier B.V. All rights reserved.
The guided tree edit distance problem is to find a minimum cost series of edit operations that transforms two input forests F and G into isomorphic forests F' and G' such that a third input forest H is include...
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The guided tree edit distance problem is to find a minimum cost series of edit operations that transforms two input forests F and G into isomorphic forests F' and G' such that a third input forest H is included in F' (and G'). The edit operations are relabeling a vertex and deleting a vertex. We show efficient algorithms for this problem that are faster than the previous algorithm for this problem of Peng and Ting [Z. Peng, H. Ting, Guided forest edit distance: Better structure comparisons by using domain-knowledge, in: Proc. 18th Symposium on Combinatorial Pattern Matching (CPM), 2007, pp. 28-39]. (C) 2008 Elsevier B.V. All rights reserved.
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