We consider a single-machine common due-window assignment scheduling problem, in which the processing time of a job is a function of its position in a sequence and its resource allocation. The window location and size...
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We consider a single-machine common due-window assignment scheduling problem, in which the processing time of a job is a function of its position in a sequence and its resource allocation. The window location and size, along with the associated job schedule that minimizes a certain cost function, are to be determined. This function is made up of costs associated with the window location, window size, earliness, and tardiness. For two different processing time functions, we provide a polynomial time algorithm to find the optimal job sequence and resource allocation, respectively.
Planar hypergraphs are widely used in several applications, including VLSI design, metro maps, information visualisation, and databases. The minimum s - t hyper- cut problem in a weighted hypergraph is to find a parti...
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Planar hypergraphs are widely used in several applications, including VLSI design, metro maps, information visualisation, and databases. The minimum s - t hyper- cut problem in a weighted hypergraph is to find a partition of the vertices into two nonempty sets, S and S, with s is an element of S and t is an element of S(sic) that minimizes the total weight of hyperedges that have at least two endpoints in two different sets. In the present study, we propose an approach that effectively solves the minimum s-t hypercut problem in (s , t)-planar hypergraphs. The method proposed demonstrates polynomialtime complexity, providing a significant advancement in solving this problem. The modelling example shows that the proposed strategy is effective at obtaining balanced bipartitions in VLSI circuits.
In this paper, we consider the parallel-machine scheduling with step-deteriorating jobs. The actual processing time of each job deteriorates as a step function if its starting time is beyond a given deteriorating date...
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In this paper, we consider the parallel-machine scheduling with step-deteriorating jobs. The actual processing time of each job deteriorates as a step function if its starting time is beyond a given deteriorating date. We focus on the case of the common job deteriorating date. For the minimization problem of total completion time, we first show that the problem is NP-hard in the strong sense. Then we propose one property of any optimal schedule. Furthermore, we prove that two special cases of common normal processing time or common penalty are polynomially solvable. For the minimization problem of total weighted completion time, we analyze the NP-hardness and present a polynomialtime optimal algorithm for the case of common normal processing time and common penalty.
Let G be an Eulerian digraph, and a,b,ca,b,ca,b,c an ordered triple of its vertices. A polynomial time algorithm of <span class="MathJax" id="MathJax-Element-2-Frame" tabindex="0" styl...
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The support of a flow x in a network is the subdigraph induced by the arcs uv for which x(uv) > 0. We discuss a number of results on flows in networks where we put certain restrictions on structure of the support o...
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The support of a flow x in a network is the subdigraph induced by the arcs uv for which x(uv) > 0. We discuss a number of results on flows in networks where we put certain restrictions on structure of the support of the flow. Many of these problems are NP-hard because they generalize linkage problems for digraphs. For example deciding whether a network N = (D. s, t, c) has a maximum flow x such that the maximum out-degree of the support D-x of x is at most 2 is NP-complete as it contains the 2-linkage problem as a very special case. Another problem which is NP-complete for the same reason is that of computing the maximum flow we can send from s to t along p paths (called a maximum p-path-flow) in N. Baier et al. (2005) gave a polynomial time algorithm which finds a-path-flow x whose value is at least 2/3 of the value of a optimum p-path-flow when p is an element of{2, 3}, and at least 1/2 when p >= 4. When p = 2, they show that this is best possible unless P=NP. We show for each p >= 2 that the value of a maximum p-path-flow cannot be approximated by any ratio larger than 9/11, unless P=NP. We also consider a variant of the problem where the p paths must be disjoint. For this problem, we give an algorithm which gets within a factor 1/H(p) of the optimum solution, where H(p) is the p'th harmonic number (H(p) similar to ln(p)). We show that in the case where the network is acyclic, we can find such a maximum p-path-flow in polynomialtime for every p. We determine the complexity of a number of related problems concerning the structure of flows. For the special case of acyclic digraphs, some of the results we obtain are in some sense best possible.
In this paper, we initiate a systematic study on a new notion called near optimal colourability which is closely related to perfect graphs and the Lovasz theta function. A graph family G is near optimal colourable if ...
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In this paper, we initiate a systematic study on a new notion called near optimal colourability which is closely related to perfect graphs and the Lovasz theta function. A graph family G is near optimal colourable if there is a constant number c such that every graph G is an element of G satisfies chi(G) <= max{c, omega(G)}, where chi (G) and omega(G) are the chromatic number and clique number of G, respectively. The near optimal colourable graph families together with the Lovasz theta function are useful for the study of the colouring problems for hereditary graph families. We investigate the near optimal colourability for (H, H-2)-free graphs. Our main result is an almost complete characterisation for the near optimal colourability for (H, H-2)-free graphs with two exceptional cases, one of which is the celebrated Gyarfas conjecture. As an application of our results, we show that the colouring problem for (2K(2), P-4 v K-n)-free graphs is polynomialtime solvable, which solves an open problem in Dabrowski and Paulusma (2018) [6].
In this paper, we propose an algorithm that solves the node-to-node disjoint paths problem in n-burnt pancake graphs in polynomial-order time of n. We also give a proof of its correctness as well as the estimates of t...
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In this paper, we propose an algorithm that solves the node-to-node disjoint paths problem in n-burnt pancake graphs in polynomial-order time of n. We also give a proof of its correctness as well as the estimates of time complexity O(n(3)) and the maximum path length 3n + 4. We conducted a computer experiment for n = 2 to 100 to measure the average performance of our algorithm. The results show that the average time complexity is O(n(3.0)) and the maximum path length is 3n + 4.
The Maximum Weight Stable Set Problem (MWS) is a well-known NP-hard problem. A popular way to study MWS is to detect graph classes for which MWS can be solved in polynomialtime. In this context some decomposition app...
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The Maximum Weight Stable Set Problem (MWS) is a well-known NP-hard problem. A popular way to study MWS is to detect graph classes for which MWS can be solved in polynomialtime. In this context some decomposition approaches have been introduced in the literature, in particular decomposition by homogeneous sets and decomposition by clique separators, which had several applications in the literature. Brandstadt and Hoang (2007) [6] showed how to combine such two decomposition approaches and stated the following result: If the MWS problem can be solved in polynomialtime for every subgraph of a graph G which has no homogeneous set and has no clique separators then so can the problem for G. This result, namely Corollary 9 of [6], was used in various papers. Unfortunately, it was stated in a successive paper by Brandstadt and Giakoumakis (2015) [5] that "Actually, [6] does not give a proof for this, and it seems that Corollary 9 of [6] promises too much;later attempts for proving it failed, and thus, it is unproven and its use has to be avoided." This manuscript introduces a proof of Corollary 9 of [6]. Furthermore a third decomposition approach, namely decomposition by anti-neighborhoods of vertices, is combined together with such two decomposition approaches. Then the various papers in which Corollary 9 of [6] was used would be fixed.(c) 2023 Elsevier B.V. All rights reserved.
作者:
Shinohara, TakumiNamerikawa, ToruKeio Univ
Grad Sch Sci & Technol 3-14-1 HiyoshiKohoku Ku Yokohama Kanagawa 2238522 Japan Keio Univ
Dept Syst Design Engn 3-14-1 HiyoshiKohoku Ku Yokohama Kanagawa 2238522 Japan
In this paper, we consider a sensor placement problem for secure state estimation in an adversarial environment. Specifically, this paper deals with a system consisting of n agents where up to l sensor measurements ar...
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In this paper, we consider a sensor placement problem for secure state estimation in an adversarial environment. Specifically, this paper deals with a system consisting of n agents where up to l sensor measurements are potentially compromised by malicious adversaries and tackles the problem of sensor placement such that the system state can be reconstructed even if the measurements are compromised. However, since it is costly to deploy sensors for all agents, we also aim to place sensors at the lowest possible cost. We call this problem the optimal resilient sensor placement problem (ORSPP) and show that this problem is coNP-hard. Therefore, it is, in general, impossible to compute the ORSPP in polynomialtime unless P = coNP. On the positive side, however, we also provide that this problem can be solved in polynomialtime if the network structure of the agents satisfies certain conditions. The concrete algorithm for the ORSPP is provided, and further, in the process of providing the coNP-hardness, we also derive a new form of a necessary and sufficient condition for secure state estimation. Finally, we show the results of numerical simulations using a random graph and a diffusion process.(c) 2023 Elsevier Ltd. All rights reserved.
Given a positive integer M and n pairs of positive integers [formula omitted], maximize the [formula omitted] subject to the constramts [formula omitted] and δi = 0 or 1 This is the well-known 0/1 knapsack problem An...
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