In this paper, based on combined homotopy interior point method we propose an interior point algorithm for convex nonlinear programming. The algorithm ensures that the obtained iterative points are interior points of ...
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In this paper, based on combined homotopy interior point method we propose an interior point algorithm for convex nonlinear programming. The algorithm ensures that the obtained iterative points are interior points of the feasible set in terms of the technique of beta-cone neighborhood. We establish the global convergence of the algorithm. Furthermore, it is shown that the algorithm has O(root nL) iteration complexity. The preliminary numerical experiments indicate that the algorithm is efficient. (C) 2007 Elsevier Inc. All rights reserved.
Given a graph G = (V, E), a set of vertices S subset of V covers v is an element of V if the edge connectivity between S and v is at least a given number k. Vertices in S are called sources. The source location proble...
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Given a graph G = (V, E), a set of vertices S subset of V covers v is an element of V if the edge connectivity between S and v is at least a given number k. Vertices in S are called sources. The source location problem is a problem of finding a minimum-size source set covering all vertices of a given graph. This paper presents a new variation of the problem, called maximum-cover source-location problem, which finds a source set S with a given size p, maximizing the sum of the weight of vertices covered by S. It presents an O(np + m + n log n)-timealgorithm for k = 2, where n = \V\ and m = \E\. Especially it runs linear time if G is connected. This algorithm uses a subroutine for finding a subtree with the maximum weight among p-leaf trees of a given vertex-weighted tree. For the problem we give a greedy-based linear-timealgorithm, which is an extension of the linear-timealgorithm for finding a longest path of a given tree presented by E. W. Dijkstra around 1960. Moreover, we show some polynomial solvable cases, e.g., a given graph is a tree or (k - 1)-edge-connected, and NP-hard cases, e.g., a vertex-cost function is given or G is a digraph.
The present paper investigates Gaussian bilateral inequalities in view of solving related probability maximization problems. Since the function f representing the probability of satisfaction of a given Gaussian bilate...
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The present paper investigates Gaussian bilateral inequalities in view of solving related probability maximization problems. Since the function f representing the probability of satisfaction of a given Gaussian bilateral inequality is not concave everywhere, we first state and prove a necessary and sufficient condition for negative semi-definiteness of the Hessian. Then, the (nonconvex) problem of globally maximizing f over a given polyhedron in Rn is adressed, and shown to be polynomial-time solvable, thus yielding a new-comer to the (short) list of nonconvex global optimization problems which can be solved exactly in polynomialtime. Application to computing upper bounds to the maximum joint probability of satisfaction of a set of m independent Gaussian bilateral inequalities is discussed and computational results are reported.
A language is factorial if it is closed under taking factors, i.e. contiguous subwords. Every factorial language can be described by an antidictionary, i.e. a minimal set of forbidden factors. We show that the problem...
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A language is factorial if it is closed under taking factors, i.e. contiguous subwords. Every factorial language can be described by an antidictionary, i.e. a minimal set of forbidden factors. We show that the problem of deciding whether a factorial language given by a finite antidictionary is well-quasi-ordered under the factor containment relation can be solved in polynomialtime. We also discuss possible ways to extend our solution to permutations and graphs. (C) 2017 Elsevier Inc. All rights reserved.
Let G be an(a) edge(vertex)-colored graph. A path P of G is called a conflict-free path if there is a color that is used on exactly one of the edges(vertices) of P. The graph G is called conflict-free (vertex-)connect...
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Let G be an(a) edge(vertex)-colored graph. A path P of G is called a conflict-free path if there is a color that is used on exactly one of the edges(vertices) of P. The graph G is called conflict-free (vertex-)connected if any two distinct vertices of G are connected by a conflict-free path, whereas the graph G is called strongly conflict-free connected if any two distinct vertices u, v of G are connected by a conflict-free path of length of a shortest path between u and v in G. For a connected graph G, the (strong)conflict-free connection number of G, denoted by (scfc(G)) cf c(G), is defined as the smallest number of colors that are required to make G (strongly) conflict-free connected. In this paper, we first investigate the question: Given a connected graph G and a coloring c : E(or V) ->{1, 2, ..., k} (k >= 1) of G, determine whether or not G is, respectively, conflict-free connected, conflict-free vertexconnected, strongly conflict-free connected under the coloring c. We solve this question by providing polynomial-time algorithms. We then show that the problem of deciding whether scfc(G) <= k (k >= 2) for a given graph G is NP-complete. Moreover, we prove that it is NP-complete to decide whether there is a k-edge-coloring (k >= 2) of G such that all pairs (u, v) is an element of P (P subset of V x V) are strongly conflict-free connected. (C) 2019 Elsevier B.V. All rights reserved.
A total dominating set of a graph G = (V, E) is a subset D of V such that every vertex in V is adjacent to at least one vertex of the set D. A total dominating set D of G is a differentiating-total dominating set of G...
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A total dominating set of a graph G = (V, E) is a subset D of V such that every vertex in V is adjacent to at least one vertex of the set D. A total dominating set D of G is a differentiating-total dominating set of G if for every pair of distinct vertices u, v is an element of V, N-G[u] boolean AND D not equal N-G[v] boolean AND D. Given a graph G, MINIMUM DIFFERENTIATING-TOTAL DOMINATION is to find a differentiating-total dominating set of minimum cardinality of G and DECIDE DIFFERENTIATING-TOTAL DOMINATION is the decision version of MINIMUM DIFFERENTIATING-TOTAL DOMINATION. In this paper, we initiate the algorithmic study of MINIMUM DIFFERENTIATING-TOTAL DOMINATION. We show that DECIDE DIFFERENTIATING-TOTAL DOMINATION is NP-complete for chordal graphs, chordal bipartite graphs, star-convex bipartite graphs, and planar graphs. On the positive side, we propose an O (log A) factor approximation algorithm for MINIMUM DIFFERENTIATING-TOTAL DOMINATION for any graph G with maximum degree delta. We match the above upper bound by showing that for general graphs as well as for bipartite graphs MINIMUM DIFFERENTIATING-TOTAL DOMINATION cannot be approximated within a factor of (1/2 - is an element of)ln vertical bar V vertical bar for any is an element of > 0 unless P= NP. Finally, we show that MINIMUM DIFFERENTIATING-TOTAL DOMINATION is APX-complete for bounded degree bipartite graphs. (C) 2021 Published by Elsevier B.V.
Tasks with long durations often face the requirement of having to periodically report their progress to process controllers. Under this requirement, working teams that simultaneously process multiple tasks need to sch...
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Tasks with long durations often face the requirement of having to periodically report their progress to process controllers. Under this requirement, working teams that simultaneously process multiple tasks need to schedule their work carefully in order to demonstrate satisfactory progress on each unfinished task. We present a single-machine scheduling model that reflects this requirement. Our model has multiple milestones at which the tasks are penalized if their progress is below a satisfactory level. We develop polynomial solution methods for the general case with convex nonlinear penalty functions and for the special case with linear penalty functions. Extensions of our model are also discussed.
We present complexity results on solving real-number standard linear programs LP(A, b, c), where the constraint matrix A is an element of R-m x n, the right-hand-side vector b is an element of R-m and the objective co...
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We present complexity results on solving real-number standard linear programs LP(A, b, c), where the constraint matrix A is an element of R-m x n, the right-hand-side vector b is an element of R-m and the objective coefficient vector c is an element of R-n are real. In particular, we present a two-layered interior-point method and show that LP(A, b, 0), i.e., the linear feasibility problem Ax = b and x >= 0, can be solved in in O(n(2.5)c(A)) interior-point method iterations. Here 0 is the vector of all zeros and c(A) is the condition measure of matrix A defined in [25]. This complexity iteration bound is reduced by a factor n from that for general LP(A, b, c) in [ 25]. We also prove that the iteration bound will be further reduced to O(n(1.5)c(A)) for LP(A, 0, 0), i.e., for the homogeneous linear feasibility problem. These results are surprising since the classical view has been that linear feasibility would be as hard as linear programming.
polynomial-time algorithms are presented for solving combinatorial packing and covering problems defined from the integral feasible flows in an integral supply-demand network. These algorithms are also shown to apply ...
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polynomial-time algorithms are presented for solving combinatorial packing and covering problems defined from the integral feasible flows in an integral supply-demand network. These algorithms are also shown to apply to packing and covering problems defined by the minimal integral solutions to general totally unimodular systems. Analogous problems arising from matroid bases are also discussed and it is demonstrated that a means for solving such problems is provided by recent work of Cunningham.
The MAxSTC problem is an assignment of the edges with two types of labels, namely, strong and weak, that maximizes the number of strong edges such that any two vertices that have a common neighbor with a strong edge a...
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The MAxSTC problem is an assignment of the edges with two types of labels, namely, strong and weak, that maximizes the number of strong edges such that any two vertices that have a common neighbor with a strong edge are adjacent. The CLUSTER DELETION problem seeks for the minimum number of edge removals of a given graph such that the remaining graph is a disjoint union of cliques. Both problems are known to be NP-hard and an optimal solution for the CLUSTER DELETION problem provides a feasible solution for the MAxSTC problem, however not necessarily an optimal one. In this work we conduct the first systematic study that reveals graph families for which the optimal solutions for MAxSTC and CLUSTER DELETION coincide. We first show that MAxSTC coincides with CLUSTER DELETION on cographs and, thus, MAxSTC is solvable in polynomialtime on cographs. As a side result, we give an interesting computational characterization of the maximum independent set on the cartesian product of two cographs. Furthermore, we address the influence of the low degree bounds to the complexity of the MAxSTC problem. We show that this problem is polynomial-time solvable on graphs of maximum degree three, whereas MAxSTC becomes NP-complete on graphs of maximum degree four. The proof of the latter result implies that there is no subexponential-timealgorithm for MAxSTC unless the Exponential-time Hypothesis fails. (C) 2018 Elsevier B.V. All rights reserved.
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