In this paper, we investigate a joint multitasking scheduling and common due date assignment problem on a single machine, for which examples can be found in product delivery process in logistics. Multitasking allows t...
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In this paper, we investigate a joint multitasking scheduling and common due date assignment problem on a single machine, for which examples can be found in product delivery process in logistics. Multitasking allows the machine to perform multiple tasks. The multitasking phenomenon has been observed in various practical domains, including manufacturing and administration. In multitasking settings, each waiting job interrupts a currently in-processing job, causing an interruption time and a switching time. In common due date assignment problems, the objective is to determine the optimal value of this due date with the purpose of minimising a total penalty function, which is associated with service quality. For the problem with general interruption functions, analytical properties are obtained to reduce the search space of the optimal solutions. For the cases with linear interruption functions, we develop a polynomial-time algorithm. Numerical experiments have been conducted to validate the efficiency of our proposed algorithm. Computational results also demonstrate an interesting phenomenon that in some cases, the optimal solutions under multitasking are superior to the counterparts without multitasking. Besides, we also devise a mixed integer programme for the cases with linear interruption function.
Classified stable matching, proposed by Huang, describes a matching model between academic institutes and applicants, in which each institute has upper and lower quotas on classes, i.e., subsets of applicants. Huang s...
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Classified stable matching, proposed by Huang, describes a matching model between academic institutes and applicants, in which each institute has upper and lower quotas on classes, i.e., subsets of applicants. Huang showed that the problem to decide whether there exists a stable matching or not is NP-hard in general. On the other hand, he showed that the problem is solvable if classes form a laminar family. For this case, Fleiner and Kamiyama gave a concise interpretation in terms of matroids and showed the lattice structure of stable matchings. In this paper we introduce stable matchings on generalized matroids, extending the model of Fleiner and Kamiyama. We design a polynomial-time algorithm which finds a stable matching or reports the nonexistence. We also show that the set of stable matchings, if nonempty, forms a lattice with several significant properties. Furthermore, we extend this structural result to the polyhedral framework, which we call stable allocations on generalized polymatroids.
In a finite undirected graph G, a vertex dominates itself and all its neighbors in G. A vertex set D is an efficient dominating set (e.d. for short) of G if every vertex of G is dominated by exactly one vertex of D. T...
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In a finite undirected graph G, a vertex dominates itself and all its neighbors in G. A vertex set D is an efficient dominating set (e.d. for short) of G if every vertex of G is dominated by exactly one vertex of D. The Efficient Domination (ED) problem, which asks for the existence of an e.d. in G, is known to be NP-complete even for very restricted graph classes such as P-7-free chordal graphs;its complexity was an open question for P-6-free graphs and was open even for the subclass of P-6-free chordal graphs. Recently, Lokshtanov et al., and independently, Brandstadt and Mosca showed that ED is solvable in polynomialtime for P-6-free graphs. The ED problem on a graph G can be reduced to the Maximum Weight Independent Set problem on the square of G. In this paper, we show that squares of P-6-free chordal graphs that have an e.d. are chordal;this, even holds for the larger class of (P-6, house, hole, domino)-free graphs. Thus, ED/WeightedED is solvable in polynomialtime for (P-6, house, hole, domino)-free graphs, and in particular, for P-6-free chordal graphs. Also, the time bound achieved for ED on this class is much better than in the P-6-free case. Moreover, we show that squares of P-6-free graphs that have an e.d. are hole-free. Based on this result, we show that ED is solvable in polynomialtime for (P-6, net)-free graphs;again, the time bound for ED on this class is much better than in the P-6-free case. (C) 2017 Elsevier B.V. All rights reserved.
作者:
Malyshev, D. S.Natl Res Univ
Higher Sch Econ 25-12 Bolshaja Pecherskaja Ulitsa Nizhnii Novgorod 603155 Russia
We completely determine the complexity status of the vertex 3-colorability problem for the problem restricted to all hereditary classes defined by at most 3 forbidden induced subgraphs each on at most 5 vertices. We a...
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We completely determine the complexity status of the vertex 3-colorability problem for the problem restricted to all hereditary classes defined by at most 3 forbidden induced subgraphs each on at most 5 vertices. We also present a complexity dichotomy for the problem and the family of all hereditary classes defined by forbidding an induced bull and any set of induced subgraphs each on at most 5 vertices.
We study the vertex coloring problem in classes of graphs defined by finitely many forbidden induced subgraphs. Of our special interest are the classes defined by forbidden induced subgraphs with at most 4 vertices. F...
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We study the vertex coloring problem in classes of graphs defined by finitely many forbidden induced subgraphs. Of our special interest are the classes defined by forbidden induced subgraphs with at most 4 vertices. For all but three classes in this family we show either NP-completeness or polynomial-time solvability of the problem. For the remaining three classes we prove fixed-parameter tractability. Moreover, for two of them we give a 3/2 approximation polynomialalgorithm. (C) 2015 Elsevier B.V. All rights reserved.
The computational challenge offered by many traditional network flow models is modest, and large-scale instances can be solved fast. When the composition of the flow is part of the model, the required computation time...
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The computational challenge offered by many traditional network flow models is modest, and large-scale instances can be solved fast. When the composition of the flow is part of the model, the required computation time may increase substantially. This is in particular true for the pooling problem, where the relative content of certain flow components is restricted. Flow entering the network at the source nodes has a given composition, whereas the composition in other nodes is determined by the composition of entering flows. At the network terminals, the flow composition is subject to restrictions referred to as quality constraints. The pooling problem is known to be strongly NP-hard, even if the network has only one pool, but is solvable in polynomialtime if also the number of terminals or the number of quality parameters (flow components) is bounded. The problem is also NP-hard if there are only two sources and terminals and only one quality parameter. Two related questions have been left open in the literature so far. For the single-pool version, it has not been known whether the problem is solvable in polynomialtime if the number of sources is bounded. For the version with a single quality parameter and two sources and terminals, the question whether a pseudo-polynomialalgorithm exists has been open. This paper gives positive answers to both questions.
The generalized k-connectivity k(k) (G) of a graph G was introduced by Chartrand et al. in (Bull Bombay Math Colloq 2:1-6, 1984), which is a nice generalization of the classical connectivity. Recently, as a natural co...
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The generalized k-connectivity k(k) (G) of a graph G was introduced by Chartrand et al. in (Bull Bombay Math Colloq 2:1-6, 1984), which is a nice generalization of the classical connectivity. Recently, as a natural counterpart, Li et al. proposed the concept of generalized edge-connectivity for a graph. In this paper, we consider the computational complexity of the generalized connectivity and generalized edge-connectivity of a graph. We give a confirmative solution to a conjecture raised by S. Li in Ph.D. Thesis (2012). We also give a polynomial-time algorithm to a problem of generalized k-edge-connectivity.
Answering a question of Haugland, we show that the pooling problem with one pool and a bounded number of inputs can be solved in polynomialtime by solving a polynomial number of linear programs of polynomial size. We...
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Answering a question of Haugland, we show that the pooling problem with one pool and a bounded number of inputs can be solved in polynomialtime by solving a polynomial number of linear programs of polynomial size. We also give an overview of known complexity results and remaining open problems to further characterize the border between (strongly) NP-hard and polynomially solvable cases of the pooling problem.
We study the design of fixed-parameter algorithms for problems already known to be solvable in polynomialtime. The main motivation is to get more efficient algorithms for problems with unattractive polynomial running...
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We study the design of fixed-parameter algorithms for problems already known to be solvable in polynomialtime. The main motivation is to get more efficient algorithms for problems with unattractive polynomial running times. Here, we focus on a fundamental graph problem: LONGEST PATH, that is, given an undirected graph, find a maximum-length path in G. LONGEST PATH is NP-hard in general but known to be solvable in O (n(4)) time on n-vertex interval graphs. We show how to solve LONGEST PATH ON INTERVAL GRAPHS, parameterized by vertex deletion number k to proper interval graphs, in 0 (k(9)n) time. Notably, LONGEST PATH is trivially solvable in linear time on proper interval graphs, and the parameter value k can be approximated up to a factor of 4 in linear time. From a more general perspective, we believe that using parameterized complexity analysis may enable a refined understanding of efficiency aspects for polynomial-time solvable problems similarly to what classical parameterized complexity analysis does for NP-hard problems. (C) 2017 Elsevier B.V. All rights reserved.
The matroid parity (or matroid matching) problem, introduced as a common generalization of matching and matroid intersection problems, is so general that it requires an exponential number of oracle calls. Lovasz (1980...
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ISBN:
(纸本)9781450345286
The matroid parity (or matroid matching) problem, introduced as a common generalization of matching and matroid intersection problems, is so general that it requires an exponential number of oracle calls. Lovasz (1980) showed that this problem admits a minmax formula and a polynomialalgorithm for linearly represented matroids. Since then efficient algorithms have been developed for the linear matroid parity problem. In this paper, we present a combinatorial, deterministic, polynomialtimealgorithm for the weighted linear matroid parity problem. The algorithm builds on a polynomial matrix formulation using Pfaffian and adopts a primal-dual approach based on the augmenting path algorithm of Gabow and Stallmann (1986) for the unweighted problem.
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