• J. Comb. Optim. (IF 0.816) Pub Date : 2020-06-02
Diego P. Rubert, Eloi Araujo, Marco A. Stefanes, Jens Stoye, Fábio V. Martinez

The analysis of biological networks allows the understanding of many biological processes, including the structure, function, interaction and evolutionary relationships of their components. One of the most important concepts in biological network analysis is that of network motifs, which are patterns of interconnections that occur in a given network at a frequency higher than expected in a random network

更新日期：2020-06-02
• J. Comb. Optim. (IF 0.816) Pub Date : 2020-06-02
Prosenjit Bose, Valentin Gledel, Claire Pennarun, Sander Verdonschot

The concept of power domination emerged from the problem of monitoring electrical systems. Given a graph G and a set $$S \subseteq V(G)$$, a set M of monitored vertices is built as follows: at first, M contains only the vertices of S and their direct neighbors, and then each time a vertex in M has exactly one neighbor not in M, this neighbor is added to M. The power domination number of a graph G is

更新日期：2020-06-02
• J. Comb. Optim. (IF 0.816) Pub Date : 2020-06-02
Brad D. Woods, Abraham P. Punnen

The quadratic travelling salesman problem (QTSP) is to find a least-cost Hamiltonian cycle in an edge-weighted graph, where costs are defined on all pairs of edges such that each edge in the pair is contained in the Hamiltonian cycle. This is a more general version than the one that appears in the literature as the QTSP, denoted here as the adjacent quadratic TSP, which only considers costs for pairs

更新日期：2020-06-02
• J. Comb. Optim. (IF 0.816) Pub Date : 2020-06-01
Hakan Kutucu, Arif Gursoy, Mehmet Kurt, Urfat Nuriyev

In order to reduce costs in the telecommunication sector, many mathematical models have been developed. Over time, these models either fall out out of use or are revised according to new technological developments. The Bandpass Problem (BP) is an optimization problem introduced in 2004 to reduce hardware costs in communication networks. However, over time, technological advances in fiber-optic networks

更新日期：2020-06-01
• J. Comb. Optim. (IF 0.816) Pub Date : 2020-05-30
E. Zhang, Feng Chu, Shijin Wang, Ming Liu, Yang Sui

This paper studies the vessel fleet deployment problem for liner shipping under uncertain shipment demands. The aim is to minimize the sum of vessel chartering cost and route operating cost, while controlling the risk of shipment demand overflow, i.e., the risk of demand exceeding the shipping capacity. We use moment knowledge to construct an ambiguous set to portray the unknown probability distributions

更新日期：2020-05-30
• J. Comb. Optim. (IF 0.816) Pub Date : 2020-05-28
Fernando A. Morales, Jairo A. Martínez

We introduce and asses several Divide-and-Conquer heuristic strategies, aimed at solving large instances of the 0–1 Minimization Knapsack Problem. The method subdivides a large problem in two smaller ones (or recursive iterations of the same procedure), in order to lower down the global computational complexity of the original problem, at the expense of a moderate loss of quality in the solution. Theoretical

更新日期：2020-05-28
• J. Comb. Optim. (IF 0.816) Pub Date : 2020-05-27
Long Zhang, Yuzhong Zhang, Qingguo Bai

This paper studies single machine scheduling with batch deliveries, where a common due window for all jobs has to be determined, not given in advance. The objective is to minimize the overall cost for the process and delivery. Concretely, it includes the penalty of a job being early or tardy, the cost for holding and delivering a job, and the cost incurred by a late starting or a long duration of the

更新日期：2020-05-27
• J. Comb. Optim. (IF 0.816) Pub Date : 2020-05-25
Tengyu Wu, Lin He, Haiyan Yu

Considering that the time of meeting the demands is very important for emergency vehicle and emergency vehicle can’t reject any request, we introduce a more realistic cost form into online traveling salesman problem(OL-TSP). When a new request arrives, if the salesman can’t serve the request immediately, per-unit-time cost will be generated. The goal is to minimize server’s total costs(travel makespan

更新日期：2020-05-25
• J. Comb. Optim. (IF 0.816) Pub Date : 2020-05-24
Chenlan Wang, Xuan Vinh Doan, Bo Chen

In this paper, we present a new model of congestion games with finite and random number of players, and an analytical method to compute the random path and link flows. We study the equilibrium condition, reformulate it as an equivalent variational inequality problem, and establish the existence and non-uniqueness of the equilibria. We also upper bound the price of anarchy with affine cost functions

更新日期：2020-05-24
• J. Comb. Optim. (IF 0.816) Pub Date : 2020-05-17
Yubai Zhang, Zhao Zhang, Zhaohui Liu

This paper studies the price of fairness in a two-agent single machine scheduling game. In this game, two agents compete to perform their jobs on a common single machine. Both of the two agents want to minimize their own total completion time. One of them has exactly two jobs. All processing times are positive. We show that all Kalai-Smorodinsky fair schedules can be found in linear time, and its price

更新日期：2020-05-17
• J. Comb. Optim. (IF 0.816) Pub Date : 2020-05-15
Lily Chen, Shumei Chen, Ren Zhao, Xiangqian Zhou

The edge weight of a graph G is defined to be $$\max \{d_G(u) + d_G(v): uv \in E(G)\}$$. The strong chromatic index of a graph is the minimum value of k such that the edge set of G can be partitioned into k induced matchings. In this article, we prove that the strong chromatic index of a graph with edge weight eight is at most 21.

更新日期：2020-05-15
• J. Comb. Optim. (IF 0.816) Pub Date : 2020-05-08
Abbas Salehi, Behrooz Masoumi

In the field of social networks, the Influence Maximization Problem (IMP) is one of the most well-known issues that have attracted many researchers in recent years. Influence Maximization (IM) means trying to find the best subset of K nodes that maximizes the number of nodes influenced by this subset. The IM is an NP-hard problem that plays an important role in viral marketing and dissemination of

更新日期：2020-05-08
• J. Comb. Optim. (IF 0.816) Pub Date : 2020-05-05
Pei Yao, Longkun Guo

For a given undirected graph with each edge associated with a weight and a length, the constrained minimum spanning tree (CMST) problem aims to compute a minimum weight spanning tree with total length bounded by a given fixed integer $$L\in {\mathbb {Z}}^{+}$$. In the paper, we first present an exact algorithm with a runtime $$O(mn^{2})$$ for CMST when the edge length is restricted to 0 and 1 based

更新日期：2020-05-05
• J. Comb. Optim. (IF 0.816) Pub Date : 2020-05-02
Rahul Swamy, Timothy Murray

This paper studies the computation of pure Nash equilibrium (PNE) in network utility-sharing and discretized Hotelling–Downs games, and the interplay between these classes of games. First, we introduce and study a variant of network utility-sharing games with additional player-specific non-shareable costs (NUSG+), which is shown to possess a PNE. We extend polynomial-time PNE computation results to

更新日期：2020-05-02
• J. Comb. Optim. (IF 0.816) Pub Date : 2020-04-29
Qin Wang, Tianyu Yang, Longshu Wu

In this paper, we study the general restricted inverse assignment problems, in which we can only change the costs of some specific edges of an assignment problem as less as possible, so that a given assignment becomes the optimal one. Under $$l_1$$ norm, we formulate this problem as a linear programming. Then we mainly consider two cases. For the case when the specific edges are only belong to the

更新日期：2020-04-29
• J. Comb. Optim. (IF 0.816) Pub Date : 2020-04-25
Changhong Lu, Qingjie Ye, Chengru Zhu

Let G be a simple graph, where each vertex has a nonnegative weight. A vertex subset S of G is a doubly resolving set (DRS) of G if for every pair of vertices u, v in G, there exist $$x,y\in S$$ such that $$d(x,u)-d(x,v)\ne d(y,u)-d(y,v)$$. The minimum weighted doubly resolving set (MWDRS) problem is finding a doubly resolving set with minimum total weight. We establish a linear time algorithm for

更新日期：2020-04-25
• J. Comb. Optim. (IF 0.816) Pub Date : 2020-04-25

Steinberg-type graphs, those planar graphs containing no 4-cycles or 5-cycles, became well known with the 1976 Steinberg Conjecture which stated that such graphs are properly 3-colorable. Recently, Steinberg’s Conjecture was demonstrated to be false (Cohen-Addad et al. in J Combin Theory Ser B 122: 452–456, 2016). However, Steinberg-type graphs are (3, 0, 0)-defective colorable (Hill et al. in Discrete

更新日期：2020-04-25
• J. Comb. Optim. (IF 0.816) Pub Date : 2020-04-25
Kelly B. Yancey, Matthew P. Yancey

In this paper we are interested in finding communities with bipartite structure. A bipartite community is a pair of disjoint vertex sets S, $$S'$$ such that the number of edges with one endpoint in S and the other endpoint in $$S'$$ is “significantly more than expected.” This additional structure is natural to some applications of community detection. In fact, using other terminology, they have already

更新日期：2020-04-25
• J. Comb. Optim. (IF 0.816) Pub Date : 2020-04-24
Ji Tian, Yan Zhou, Ruyan Fu

We consider a semi-online scheduling problem on a single machine with an unexpected breakdown period. In the problem, each job has a processing time and a subsequent delivery time. All these data are known in the beginning. The scheduler has to determine a sequence S of these jobs for processing. After S is given, a machine unavailability period may occur where its starting time and length are not

更新日期：2020-04-24
• J. Comb. Optim. (IF 0.816) Pub Date : 2020-04-22
Thi Thanh Sang Nguyen, Pham Minh Thu Do

Book classification is very popular in digital libraries. Book rating prediction is crucial to improve the care of readers. The commonly used techniques are decision tree, Naïve Bayes (NB), neural networks, etc. Moreover, mining book data depends on feature selection, data pre-processing, and data preparation. This paper proposes the solutions of knowledge representation optimization as well as feature

更新日期：2020-04-22
• J. Comb. Optim. (IF 0.816) Pub Date : 2020-04-15
Sai Ji, Dachuan Xu, Longkun Guo, Min Li, Dongmei Zhang

Spherical k-means clustering as a known NP-hard variant of the k-means problem has broad applications in data mining. In contrast to k-means, it aims to partition a collection of given data distributed on a spherical surface into k sets so as to minimize the within-cluster sum of cosine dissimilarity. In the paper, we introduce spherical k-means clustering with penalties and give a $$2\max \{2,M\}(1+M)(\ln 更新日期：2020-04-15 • J. Comb. Optim. (IF 0.816) Pub Date : 2020-04-13 Zohreh Hosseini Nodeh, Ali Babapour Azar, Rashed Khanjani Shiraz, Salman Khodayifar, Panos M. Pardalos In this paper, we investigate the constrained shortest path problem where the arc resources of the problem are dependent normally distributed random variables. A model is presented to maximize the probability of all constraints, while not exceeding a certain amount. We assume that the rows of the constraint matrix are dependent, so we use a marginal distribution of the Copula functions, instead of 更新日期：2020-04-13 • J. Comb. Optim. (IF 0.816) Pub Date : 2020-04-11 M. R. Chithra, Manju K. Menon The topological structure of a network can be described by a connected graph \(G = (V, E)$$ where V(G) is a set of nodes to be connected and E(G) is a set of direct communication links between the nodes. A physical connection between the different components of a parallel system is provided by an interconnection network. Many graph theoretic parameters are used to study the efficiency and reliability

更新日期：2020-04-11
• J. Comb. Optim. (IF 0.816) Pub Date : 2020-04-09
Anuj Rawat, Mark Shayman

A rooted tree $$\mathbf {R}$$ is a rooted subtree of a tree T if the tree obtained by replacing the directed edges of $$\mathbf {R}$$ by undirected edges is a subtree of T. We study the problem of assigning minimum number of colors to a given set of rooted subtrees $${\mathcal {R}}$$ of a given tree T such that if any two rooted subtrees share a directed edge, then they are assigned different colors

更新日期：2020-04-09
• J. Comb. Optim. (IF 0.816) Pub Date : 2020-04-09
Yan Liu, Mengxia Lei, Xueli Su

A fractional matching of a graph G is a function f that assigns to each edge a number in [0, 1] such that for each vertex v, $$\sum \nolimits _{e\in \Gamma (v)}f(e) \le 1$$, where $$\Gamma (v)$$ is the set of all edges incident with v. The fractional matching number $$\mu _{f}(G)$$ of G is the supremum of $$\sum \nolimits _{e\in E(G)}f(e)$$ over all fractional matchings f of G. Let $$D_f(G)$$ be the

更新日期：2020-04-09
• J. Comb. Optim. (IF 0.816) Pub Date : 2020-04-06
Haitao Wu, Yaojun Chen, Xiaolan Hu

Let $$G=(V(G),E(G))$$ be a graph and s, t integers with $$s\le t$$. If we can assign an s-subset $$\phi (v)$$ of the set $$\{1, 2,\ldots ,t\}$$ to each vertex v of V(G) such that $$\phi (u)\cap \phi (v)=\emptyset$$ for every edge $$uv\in E(G)$$, then G is called (t : s)-colorable, and such an assignment $$\phi$$ is called a (t : s)-coloring of G. Let $$C_n$$ denote a cycle of length n. In this paper

更新日期：2020-04-06
• J. Comb. Optim. (IF 0.816) Pub Date : 2020-03-19
Xiang Li, H. George Du, Panos M. Pardalos

Any set function can be decomposed into the difference of two monotone nondecreasing submodular functions. This theorem plays an important role in the set function optimization theory. In this paper, we show a variation that any set function can be decomposed into the difference of two monotone nondecreasing supermodular functions. Meanwhile, we give an example in social network optimization and construct

更新日期：2020-03-19
• J. Comb. Optim. (IF 0.816) Pub Date : 2020-03-16
Wei Ding, Ke Qiu

The asymmetric p-center problem (ApCP) was proved by Chuzhoy et al. (STOC’04) to be NP-hard to approximate within a factor of $$\log ^*n - \Theta (1)$$ unless $$\mathrm {NP} \subseteq \mathrm {DTIME}(n^{\log \log n})$$. This paper studies ApCP and the vertex-weighted asymmetric p-center problem (WApCP). First, we propose four classes of parameterized complete digraphs, $$\alpha$$-CD, $$(\alpha , \beta 更新日期：2020-03-16 • J. Comb. Optim. (IF 0.816) Pub Date : 2020-03-13 Jiangxu Kong, Xiaoxue Hu, Yiqiao Wang A plane graph G is entirely k-colorable if \(V(G)\cup E(G) \cup F(G)$$ can be colored with k colors such that any two adjacent or incident elements receive different colors. In 2011, Wang and Zhu conjectured that every plane graph G with maximum degree $$\Delta \ge 3$$ and $$G\ne K_4$$ is entirely $$(\Delta +3)$$-colorable. It is known that the conjecture holds for the case $$\Delta \ge 8$$. The condition

更新日期：2020-03-13
• J. Comb. Optim. (IF 0.816) Pub Date : 2020-03-12
Qingqin Nong, Jiazhu Fang, Suning Gong, Dingzhu Du, Yan Feng, Xiaoying Qu

Maximizing non-monotone submodular functions is one of the most important problems in submodular optimization. Let $$\mathbf {B}=(B_1, B_2,\ldots , B_n)\in {\mathbb {Z}}_+^n$$ be an integer vector and $$[\mathbf { B}]=\{(x_1,\dots ,x_n) \in {\mathbb {Z}}_+^n: 0\le x_k \le B_k, \forall 1\le k\le n\}$$ be the set of all non-negative integer vectors not greater than $$\mathbf {B}$$. A function $$f:[\mathbf 更新日期：2020-03-12 • J. Comb. Optim. (IF 0.816) Pub Date : 2020-03-07 Assaf Kfoury, Benjamin Sisson A reassembling of a simple graph \(G = (V,E)$$ is an abstraction of a problem arising in earlier studies of network analysis (Bestavros and Kfoury, in: Proceedings of IFIP working conference on domain-specific 1640 languages (DSL 2011), EPTCS volume 66, 2011; Kfoury, in: Proceedings of SBLP 2011: Brazilian symposium on programming; Kfoury, in Sci Comput Program 93(Part A):19–38; Soule et al., in: Proceedings

更新日期：2020-03-07
• J. Comb. Optim. (IF 0.816) Pub Date : 2020-02-27
Yulin Chang, Fei Jing, Guanghui Wang

An antimagic labelling of a digraph D with m arcs is a bijection from the set of arcs of D to $$\{1,\ldots ,m\}$$ such that any two vertices have distinct vertex-sums, where the vertex-sum of a vertex $$v\in V(D)$$ is the sum of labels of all arcs entering v minus the sum of labels of all arcs leaving v. An orientation D of a graph G is antimagic if D has an antimagic labelling. In 2010, Hefetz, M$$\ddot{\text 更新日期：2020-02-27 • J. Comb. Optim. (IF 0.816) Pub Date : 2020-02-25 Frank de Meijer, Renata Sotirov The quadratic cycle cover problem is the problem of finding a set of node-disjoint cycles visiting all the nodes such that the total sum of interaction costs between consecutive arcs is minimized. In this paper we study the linearization problem for the quadratic cycle cover problem and related lower bounds. In particular, we derive various sufficient conditions for the quadratic cost matrix to be 更新日期：2020-02-25 • J. Comb. Optim. (IF 0.816) Pub Date : 2020-02-25 Sajjad Salehi, Fattaneh Taghiyareh Study of social structure patterns and their dynamics has attracted more attentions in recent years. Structural measures like structural balance and status theory focus on patterns of signed links and the frequency/popularity of them. Several recent works have tried to define some measures to study the instability of social structure. But these works do not present any idea about the links that changing 更新日期：2020-02-25 • J. Comb. Optim. (IF 0.816) Pub Date : 2020-02-23 Dawei Li, Xiwen Lu In this paper, we consider the two-machine flow shop scheduling with an operator non-availability period in the first stage to minimize makespan, where the operator non-availability period is an open time interval in which a job can neither start nor complete. We first prove that the problem is NP-hard, even if the length of the operator non-availability period is no more than the processing time of 更新日期：2020-02-23 • J. Comb. Optim. (IF 0.816) Pub Date : 2020-02-18 Atílio G. Luiz, C. N. Campos, Simone Dantas, Diana Sasaki A labelling of a graph G is a mapping \(\pi :S \rightarrow {\mathcal {L}}$$, where $${\mathcal {L}}\subset {\mathbb {R}}$$ and $$S \subseteq V(G)\cup E(G)$$. If $$S=E(G)$$, $$\pi$$ is an $${\mathcal {L}}$$-edge-labelling and, if $$S=V(G)\cup E(G)$$, $$\pi$$ is an $${\mathcal {L}}$$-total-labelling. For each $$v\in V(G)$$, the colour of v under $$\pi$$ is defined as $$C_{\pi }(v) = \sum _{uv \in 更新日期：2020-02-18 • J. Comb. Optim. (IF 0.816) Pub Date : 2020-02-14 Amit Kumar Dhar, Raghunath Reddy Madireddy, Supantha Pandit, Jagpreet Singh Set cover is one of the most studied optimization problems in Computer Science. In this paper, we target two interesting variations of this problem in a geometric setting: (i) maximum disjoint coverage (MDC), and (ii) maximum independent coverage (MIC) problems. In both problems, the input consists of a set P of points and a set O of geometric objects in the plane. The objective is to maximize the 更新日期：2020-02-14 • J. Comb. Optim. (IF 0.816) Pub Date : 2020-02-07 Sergey Bereg, Andrew Brunner, Luis-Evaristo Caraballo, José-Miguel Díaz-Báñez, Mario A. Lopez Area coverage and communication are fundamental concerns in networks of cooperating robots. The goal is to address the issue of how well a group of collaborating robots having a limited communication range is able to monitor a given geographical space. Typically, an area of interest is partitioned into smaller subareas, with each robot in charge of a given subarea. This gives rise to a communication 更新日期：2020-02-07 • J. Comb. Optim. (IF 0.816) Pub Date : 2020-02-04 Qiulan Zhao, Zhibin Chen, Jiajun Sang Given a multigraph \(G=(V,E)$$, the edge cover packing problem (ECPP) on G is to find a coloring of edges of G using the maximum number of colors such that at each vertex all colors occur. ECPP can be formulated as an integer program and is NP-hard in general. In this paper, we consider the fractional edge cover packing problem, the LP relaxation of ECPP. We focus on the more general weighted setting

更新日期：2020-02-04
• J. Comb. Optim. (IF 0.816) Pub Date : 2020-02-04
Yi Chu, Boxiao Liu, Shaowei Cai, Chuan Luo, Haihang You

Maximum vertex weight clique problem (MVWCP) and maximum edge weight clique problem (MEWCP) are two significant generalizations of maximum clique problem (MCP), and can be widely used in many real-world applications including molecular biology, broadband network design and pattern recognition. Recently, breakthroughs have been made for solving MVWCP in large graphs, resulting in several state-of-the-art

更新日期：2020-02-04
• J. Comb. Optim. Pub Date : 2011-05-06
Chunmei Liu,Legand Burge,Ajoni Blake

Given a number of users each of which provides a set of services with a cost for each service and has a set of requests to be satisfied, the goal of the request-service problem is to find a feasible solution that satisfies all requests of each user with minimum cost. In addition, a feasible solution must satisfy an additional constraint. Specifically, if user A provides a service to user B, B should

更新日期：2019-11-01
• J. Comb. Optim. Pub Date : 2010-04-15
Chunmei Liu,Yinglei Song

In this paper, we study the parameterized complexity of Dominating Set problem in chordal graphs and near chordal graphs. We show the problem is W[2]-hard and cannot be solved in time no(k) in chordal and s-chordal (s > 3) graphs unless W[1]=FPT. In addition, we obtain inapproximability results for computing a minimum dominating set in chordal and near chordal graphs. Our results prove that unless

更新日期：2019-11-01
• J. Comb. Optim. Pub Date : 2009-01-01
Shivkumar Sabesan,Niranjan Chakravarthy,Kostas Tsakalis,Panos Pardalos,Leon Iasemidis

Epileptic seizures are manifestations of intermittent spatiotemporal transitions of the human brain from chaos to order. Measures of chaos, namely maximum Lyapunov exponents (STL(max)), from dynamical analysis of the electroencephalograms (EEGs) at critical sites of the epileptic brain, progressively converge (diverge) before (after) epileptic seizures, a phenomenon that has been called dynamical synchronization

更新日期：2019-11-01
• J. Comb. Optim. Pub Date : 2008-12-17
Chang-Chia Liu,Panos M Pardalos,W Art Chaovalitwongse,Deng-Shan Shiau,Georges Ghacibeh,Wichai Suharitdamrong,J Chris Sackellares

Epilepsy is a brain disorder characterized clinically by temporary but recurrent disturbances of brain function that may or may not be associated with destruction or loss of consciousness and abnormal behavior. Human brain is composed of more than 10 to the power 10 neurons, each of which receives electrical impulses known as action potentials from others neurons via synapses and sends electrical impulses

更新日期：2019-11-01
• J. Comb. Optim. Pub Date : 2008-04-01
Linda Hermer-Vazquez

PRIMARY OBJECTIVE: To determine the relative uses of neural action potential ('spike') data versus local field potentials (LFPs) for modeling information flow through complex brain networks. HYPOTHESIS: The common use of LFP data, which are continuous and therefore more mathematically suited for spectral information-flow modeling techniques such as Granger causality analysis, can lead to spurious inferences

更新日期：2019-11-01
• J. Comb. Optim. Pub Date : 2006-04-19
Jinhui Xu,Guang Xu,Zhenming Chen,Vikas Singh,Kenneth R Hoffmann

Biplane projection imaging is one of the primary methods for imaging and visualizing the cardiovascular system in medicine. A key problem in such a technique is to determine the imaging geometry (i.e., the relative rotation and translation) of two projections so that the interested 3-D structures can be accurately reconstructed. Based on interesting observations and efficient geometric techniques,

更新日期：2019-11-01
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