检索结果-内蒙古大学图书馆

BIPARTITE SUBGRAPHS OF TRIANGLE-FREE GRAPHS

SIAM JOURNAL ON DISCRETE MATHEMATICS 1994年第2期7卷 307-313页

作者： POLJAK, S TUZA, Z HUNGARIAN ACAD SCI INST COMP & AUTOMATH-1111 BUDAPESTHUNGARY

The authors present a lower bound on the maximum size of a bipartite subgraph of a triangle-free graph that improves a result due to Erdos and Lovasz. It also gives a polynomial-time algorithm, while the previous boun... 详细信息

关键词： TRIANGLE-FREE GRAPH MAXIMUM BIPARTITE SUBGRAPH polynomial-time algorithm

来源：评论

学校读者我要写书评

暂无评论

Deciding k-Colorability of P ₅-Free Graphs in polynomial time

引用

algorithmICA 2010年第1期57卷 74-81页

作者： Hoang, Chinh T. Kaminski, Marcin Lozin, Vadim Sawada, Joe Shu, Xiao Wilfrid Laurier Univ Waterloo ON N2L 3C5 Canada Rutgers State Univ RUTCOR Piscataway NJ 08854 USA Univ Warwick DIMAP Coventry CV4 7AL W Midlands England Univ Warwick Math Inst Coventry CV4 7AL W Midlands England Univ Guelph Guelph ON N1G 2W1 Canada

The problem of computing the chromatic number of a P (5)-free graph (a graph which contains no path on 5 vertices as an induced subgraph) is known to be NP-hard. However, we show that for every fixed integer k, there exists a polynomial-time algorithm determining whether or not a P (5)-free graph admits a k-coloring, and finding one, if it does.

关键词： Graph coloring Dominating clique polynomial-time algorithm P(5)-free graph

来源：评论

学校读者我要写书评

暂无评论

引用

INTERNATIONAL JOURNAL OF PRODUCTION RESEARCH 2014年第13期52卷 3793-3801页

作者： Vakhania, Nodari Alberto Hernandez, Jose Werner, Frank UAEM Fac Sci Cuernavaca Morelos Mexico Otto Von Guericke Univ Fak Math Magdeburg Germany

In this paper, we consider the problem of scheduling a set of jobs having only two possible processing times on a set of unrelated parallel machines. This problem is a generalisation of the much more common problem of scheduling equal-length jobs on identical machines. Such a situation may occur in the production of two different types of products. First, we show that an earlier open problem of scheduling jobs with two possible processing times p and 2p on unrelated machines with the objective to minimise the makespan can be polynomially solved by an algorithm consisting of two phases. A slight modification of this algorithm yields an absolute worst-case error of q for the case of two arbitrary processing times p and q, p < q. Thus, for practical problems of a large size with two types of products and two possible processing times, the approximation algorithm generates schedules very close to an optimal one.

关键词： scheduling unrelated machines linear programming polynomial-time algorithm approximation algorithm worst-case analysis

来源：评论

学校读者我要写书评

暂无评论

Refined Computational Complexities of Hospitals/Residents Problem with Regional Caps 28th

Refined Computational Complexities of Hospitals/Residents Pr...

引用

28th International Computing and Combinatorics Conference (COCOON)

作者： Hamada, Koki Miyazaki, Shuichi NTT Social Informat Labs 3-9-11 Midori Cho Musashino Tokyo 1808585 Japan Univ Hyogo Nishi Ku 8-2-1 Gakuennishi Machi Kobe Hyogo 6512197 Japan

ISBN: (纸本)9783031221040;9783031221057

The Hospitals/Residents problem (HR) is a many-to-one matching problem whose solution concept is stability. It is widely used in assignment systems such as assigning medical students (residents) to hospitals. To resolve imbalance in the number of residents assigned to hospitals, an extension called HR with regional caps (HRRC) was introduced. In this problem, a positive integer (called a regional cap) is associated with a subset of hospitals (called a region), and the total number of residents assigned to hospitals in a region must be at most its regional cap. Kamada and Kojima [11,13] defined strong stability for HRRC and demonstrated that a strongly stable matching does not necessarily exist. Recently, Aziz et al. [3] proved that the problem of determining if a strongly stable matching exists is NP-complete in general. In this paper, we refine Aziz et al.'s result by investigating the computational complexity of the problem in terms of the length of preference lists, the size of regions, and whether or not regions can overlap, and completely classify tractable and intractable cases.

关键词： Hospitals/residents problem Stable matching Strong stability Regional cap Computational complexity polynomial-time algorithm NP-completeness

来源：评论

学校读者我要写书评

暂无评论

Method for Finding Protected Nodes for Robust Network against Node Failures 6

Method for Finding Protected Nodes for Robust Network agains...

引用

2014 International Conference on Intelligent Networking and Collaborative Systems (IEEE INCoS 2014)

作者： Matsui, Tomomi Miwa, Hiroyoshi Kwansei Gakuin Univ Grad Sch Sci & Technol 2-1 Gakuen Sanda Hyogo 6691337 Japan

ISBN: (纸本)9781479963874

The reliability of a communication network is important, as the Internet is an important social infrastructure. However, especially in a large network, it is difficult to avoid the failures due to various factors. It is necessary to design a network that keeps communication among nodes even during failures. However, in many actual networks, there exists the risk of telecommunication blackout by a node failure or attack. To get rid of this risk, it is necessary to design a network so that many nodes can communicate mutually even if nodes fail. It is desirable that all nodes have their backup facility, but it needs much cost;therefore, at least critical nodes whose failures fragment a network to many small connected components must be protected by backup facility. We addressed a problem to determine protected nodes such that, even if non-protected nodes fail, the minimum size of the connected components of a remaining network is not less than a threshold. In this paper, we propose an approximation algorithm with the approximation ratio of two for the problem restricted to the case that at most two nodes simultaneously fail. Moreover, we evaluate the performance of the approximation algorithm by using actual network topologies.

关键词： Quality of service Node failure Node attack Node protection Network design Optimization NP-hard Approximation algorithm polynomial-time algorithm

来源：评论

学校读者我要写书评

暂无评论

An Efficient algorithm for the Fast Delivery Problem 22nd

An Efficient Algorithm for the Fast Delivery Problem

引用

22nd International Symposium on Fundamentals of Computation Theory (FCT)

作者： Carvalho, Iago A. Erlebach, Thomas Papadopoulos, Kleitos Univ Fed Minas Gerais Dept Comp Sci Belo Horizonte MG Brazil Univ Leicester Dept Informat Leicester Leics England

ISBN: (纸本)9783030250270;9783030250263

We study a problem where k autonomous mobile agents are initially located on distinct nodes of a weighted graph (with n nodes and m edges). Each autonomous mobile agent has a predefined velocity and is only allowed to move along the edges of the graph. We are interested in delivering a package, initially positioned in a source node s, to a destination node y. The delivery is achieved by the collective effort of the autonomous mobile agents, which can carry and exchange the package among them. The objective is to compute a delivery schedule that minimizes the delivery time of the package. In this paper, we propose an (O(kn log(kn) + km) time algorithm for this problem. This improves the previous state-of-the-art (O(k(2)m + kn(2) + APSP) time algorithm for this problem, where APSP stands for the running-time of an algorithm for the All-Pairs Shortest Paths problem.

关键词： Mobile agents Dijkstra's algorithm polynomial-time algorithm time-dependent shortest paths

来源：评论

学校读者我要写书评

暂无评论

On Reachable Assignments in Cycles 7th

On Reachable Assignments in Cycles

引用

7th International Conference on algorithmic Decision Theory (ADT)

作者： Mueller, Luis Bentert, Matthias TU Berlin Algorithm & Computat Complex Berlin Germany

ISBN: (纸本)9783030877569;9783030877552

The efficient and fair distribution of indivisible resources among agents is a common problem in the field of Multi-Agent-Systems. We consider a graph-based version of this problem called REACHABLE ASSIGNMENT, introduced by Gourves, Lesca, and Wilczynski [IJCAI, 2017]. The input for this problem consists of a set of agents, a set of objects, the agent's preferences over the objects, a graph with the agents as vertices and edges encoding which agents can trade resources with each other, and an initial and a target distribution of the objects, where each agent owns exactly one object in each distribution. The question is then whether the target distribution is reachable via a sequence of rational trades. A trade is rational when the two participating agents are neighbors in the graph and both obtain an object they prefer over the object they previously held. We show that REACHABLE ASSIGNMENT is solvable in O(n(3)) time when the input graph is a cycle with n vertices.

关键词： Multi-Agent Systems Resource allocation polynomial-time algorithm Reduction to 2-SAT

来源：评论

学校读者我要写书评

暂无评论

Metric Extension Operators, Vertex Sparsifiers and Lipschitz Extendability

Metric Extension Operators, Vertex Sparsifiers and Lipschitz...

引用

2010 IEEE 51st Annual Symposium on Foundations of Computer Science

作者： Makarychev, Konstantin Makarychev, Yury IBM TJ Watson Res Ctr Yorktown Hts NY 10598 USA Toyota Technol Inst Chicago IL USA

ISBN: (纸本)9780769542447

We study vertex cut and flow sparsifiers that were recently introduced by Moitra [23], and Leighton and Moitra [18]. We improve and generalize their results. We give a new polynomial-time algorithm for constructing O(log k / log log k) cut and flow sparsifiers, matching the best known existential upper bound on the quality of a sparsifier, and improving the previous algorithmic upper bound of O(log(2) k / log log k). We show that flow sparsifiers can be obtained from linear operators approximating minimum metric extensions. We introduce the notion of (linear) metric extension operators, prove that they exist, and give an exact polynomial-time algorithm for finding optimal operators. We then establish a direct connection between flow and cut sparsifiers and Lipschitz extendability of maps in Banach spaces, a notion studied in functional analysis since 1950s. Using this connection, we obtain a lower bound of Omega(root log k / log log k) for flow sparsifiers and a lower bound of Omega(root log k / log log k) for cut sparsifiers. We show that if a certain open question posed by Ball in 1992 has a positive answer, then there exist (O) over tilde(root log k) cut sparsifiers. On the other hand, any lower bound on cut sparsifiers better than (Omega) over tilde(root log k) would imply a negative answer to this question.

关键词： Banach spaces Banach spaces Lipschitz extendability algorithmic upper bound computational complexity flow sparsifiers functional analysis functional analysis linear metric extension operators linear operators lipschitz extendability minimum metric extensions optimal operators polynomial-time algorithm vertex cut vertex sparsifiers

来源：评论

学校读者我要写书评

暂无评论

Finding additive biclusters with random background

引用

19th Annual Symposium on Combinatorial Pattern Matching

作者： Xiao, Jing Wang, Lusheng Liu, Xiaowen Jiang, Tao Tsinghua Univ Dept Comp Sci & Technol Beijing Peoples R China City Univ Hong Kong Dept Comp Sci Hong Kong Hong Kong Peoples R China Univ Western Ontario Dept Comp Sci London ON Canada Univ Calif Dept Comp Sci & Engn Riverside CA 92521 USA

ISBN: (纸本)9783540690665

The biclustering problem has been extensively studied in many areas including e-commerce, data mining, machine learning, pattern recognition, statistics, and more recently in computational biology. Given an n x m matrix A (n >= m), the main goal of biclustering is to identify a subset of rows (called objects) and a subset of columns (called properties) such that some objective function that specifies the quality of the found bicluster (formed by the subsets of rows and of columns of A) is optimized. The problem has been proved or conjectured to be NP-hard under various mathematical models. In this paper, we study a probabilistic model of the implanted additive bicluster problem, where each element in the n x m background matrix is a random number from [0, L - 1], and a k x k implanted additive bicluster is obtained from an error-free additive bicluster by randomly changing each element to a number in [0, L - 1] with probability theta. We propose an O(n(2)m) time voting algorithm to solve the problem. We show that for any constant 6 such that (1 - delta)(1 - theta)(2) - 1/L > 0, when k >= max {8/alpha root nlog n, 8logn/c + log(2L)}, where c is a constant number, the voting algorithm can correctly find the implanted bicluster with probability at least 1 - 9/n(2). We also implement our algorithm as a software tool for finding novel biclusters in microarray gene expression data, called VOTE. The implementation incorporates several nontrivial ideas for estimating the size of an implanted bicluster, adjusting the threshold in voting, dealing with small biclusters, and dealing with multiple (and overlapping) implanted biclusters. Our experimental results on both simulated and real datasets show that VOTE can find biclusters with a high accuracy and speed.

关键词： bicluster Chernoff bound polynomial-time algorithm probability model computational biology gene expression data analysis

来源：评论

学校读者我要写书评

暂无评论

A diameter-based model of the rectilinear partitioning problem in VLSI physical design

A diameter-based model of the rectilinear partitioning probl...

引用

Chinese Automation Congress (CAC)

作者： Lin, Lan Wu, Tong Zhang, Zhifeng Tongji Univ Dept Elect Sci & Technol Shanghai Peoples R China

ISBN: (纸本)9781728176871

The rectilinear point-partitioning problem in VLSI physical design can be stated as follows: Given n points in the plane and a number p with 1 <= p < n/2, find p disjoint axis-parallel rectangles R-1, R-2, ..., R-p containing these n points so that the total area of the rectangles is minimized. This area-based model may suffer from the degenerate case where areas of some rectangles vanish. This case is meaningless in VLSI physical design. Moreover, the sizes of rectangles may have great difference in an optimal solution. It is well known that there are several optimization criteria in integrated circuit design (such as area, wirelength, cross number, etc). This paper proposes a new model by replacing the objective function from the total area to the maximum diameter of the rectangles. Our main result is to present improved algorithms, in which the time complexity of a partitioning procedure is reduced from O(n) to O(log n).

关键词： VLSI physical design rectilinear partition maximum diameter polynomial-time algorithm

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：