A matchable set of a graph is a set of vertices joined in pairs by disjoint edges. Balas and Pulleyblank gave a linear-inequality description of the convex hull of matchable sets. We give a polynomial-time conbinatori...
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A matchable set of a graph is a set of vertices joined in pairs by disjoint edges. Balas and Pulleyblank gave a linear-inequality description of the convex hull of matchable sets. We give a polynomial-time conbinatorial algorithm for the separation problem for this polytope, and a min-max theorem characterizing the maximum violation by a given point of an inequality of the system.
We consider the tree partition problem to partition the node set of a tree into subsets where the induced subgraph by each subset is connected and the total weight of nodes in a subset cannot exceed the capacity of th...
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A new separation algorithm based on contour segments and ellipse fitting is proposed to separate the ellipse-like touching grain kernels in digital *** image is filtered and converted into a binary image *** the conto...
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A new separation algorithm based on contour segments and ellipse fitting is proposed to separate the ellipse-like touching grain kernels in digital *** image is filtered and converted into a binary image *** the contour of touching grain kernels is extracted and divided into contour segments (CS) with the concave points on *** next step is to merge the contour segments,which is the main contribution of this *** distance measurement (DM) and deviation error measurement (DEM) are proposed to test whether the contour segments pertain to the same kernel or *** they pass the measurement and judgment,they are merged as a new *** with these newly merged contour segments,the ellipses are fitted as the representative ellipses for touching *** verify the proposed algorithm,six different kinds of Korean grains were *** results showed that the proposed method is efficient and accurate for the separation of the touching grain kernels.
Maximum likelihood (ML) decoding is the optimal decoding algorithm for arbitrary linear block codes and can be written as an integer programming (IP) problem. Feldman et al. relaxed this IP problem and presented linea...
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Maximum likelihood (ML) decoding is the optimal decoding algorithm for arbitrary linear block codes and can be written as an integer programming (IP) problem. Feldman et al. relaxed this IP problem and presented linear programming (LP) based decoding. In this paper, we propose a new separation algorithm to improve the error-correcting performance of LP decoding for binary linear block codes. We use an IP formulation with indicator variables that help in detecting the violated parity checks. We derive Gomory cuts from the IP and use them in our separation algorithm. An efficient method of finding cuts induced by redundant parity checks (RPC) is also proposed. Under certain circumstances we can guarantee that these RPC cuts are valid and cut off the fractional optimal solutions of LP decoding. It is demonstrated on three LDPC codes and two BCH codes that our separation algorithm performs significantly better than LP decoding and belief propagation (BP) decoding.
Twice a year, the regional school departments in Norway need to schedule examination sessions for external candidates in the region, which also involves reserving and assigning rooms, examiners and reviewers. We prese...
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Twice a year, the regional school departments in Norway need to schedule examination sessions for external candidates in the region, which also involves reserving and assigning rooms, examiners and reviewers. We present a cut-and-branch algorithm to get provably good solutions to this problem, the external candidates examination scheduling problem (ExtSchedule). The algorithm relies on a new family of valid inequalities, effective in tightening the initial formulation and accelerating the solution process. We develop an efficient separation algorithm and embed it in a cut-and-branch framework to solve the problem. The algorithm has been validated on real-life instances arising from the Vestfold County school department in Norway.
In this article we investigate some strategies for solving set partitioning problems (SPP), in particular the gains in computational efficiency that can be obtained by introducing cutting planes based on some rank-1 C...
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In this article we investigate some strategies for solving set partitioning problems (SPP), in particular the gains in computational efficiency that can be obtained by introducing cutting planes based on some rank-1 Chvatal-Gomory inequalities and clique inequalities. We show that for many instances of the SPP, the introduction of some of these cutting planes into the standard SPP model enables a commercial solver such as CPLEX to compute optimal solutions more efficiently.
The joint delivery of parcels by trucks and drones is a futuristic scenario that already started. As a result of this development, new optimization problems are defined and studied. In this paper, exact separation alg...
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ISBN:
(纸本)9783030876722;9783030876715
The joint delivery of parcels by trucks and drones is a futuristic scenario that already started. As a result of this development, new optimization problems are defined and studied. In this paper, exact separation algorithms for the Parallel Drone Scheduling Traveling Salesman Problem are presented. Known separation algorithms for subtour elimination constraints and 2-matching inequalities are modified and applied to the new context. In addition, a new valid inequality for an invalid drone-truck subtour is given. For this inequality, a simple separation algorithm with a runtime of O(n(2)) for n nodes (customers) is presented. It is shown that this problem specific separation algorithm reduces the total runtime of problem instances more effectively compared to modified TSP approaches, especially for instances with a large number of customers that can be served by a drone. These separation algorithms are used to solve instances with up to 127 customers by a branch and cut algorithm.
Speech separation is among the propelled advances for a wide range of uses in different sectors, where detachment from the Blind Source separation Signal is a troublesome task. Blind source separation is a growing dig...
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Speech separation is among the propelled advances for a wide range of uses in different sectors, where detachment from the Blind Source separation Signal is a troublesome task. Blind source separation is a growing digital signal processing industry to separate the precise signal from the recorded dense. Exclusively, among the "Blind Source separation," the "Under Determined Blind Source separation" is considered as an Over Determined Blind Source separation due to its wide range of usage. Nevertheless, it is seen that real implementation is very rarely done in existing researches because the real-time Implementation of UBSS (Underdetermined Blind Source separation) exists to be a challenging one due to its lacking hardware characteristics of increased latency, reduced speed and consumption of more memory space. Consequently, an increasing need to implement an Underdetermined source signal separation in real-time with improved hardware utility. In this Unswerving framework, a Real-time feasible Source Signal separator formulated in which the source signals decomposed by Boosted Band-Limited VMD (Variational Mode Decomposition) "Multicomponent Signal". The amount of "BandLimited" Intrinsic Mode Function (BLIMF) was subjected to the Encompassed Hammersley-Clifford algorithm for source separation using Expectation-Maximization and Gibbs Sampling, an alternative to deterministic algorithms and to determine the exact estimated parameter from the E-M method. Subsequently, the source separation algorithm infers the best separation of source signals by exact estimation and determination from the decomposed signals. The iterations in E-M estimation reduced by the Gauss-Seidel Method. Thus, our novel source signal separates internally with a signal decomposer and a source separation algorithm with fewer iterations, which reduces memory consumption and yields better hardware realization with reduced latency and increased speed. The proposed implementation is done by utilizing M
The max-cut problem and the associated cut polytope on complete graphs have been extensively studied over the last 25 years. However, in comparison, only little research has been conducted for the cut polytope on arbi...
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The max-cut problem and the associated cut polytope on complete graphs have been extensively studied over the last 25 years. However, in comparison, only little research has been conducted for the cut polytope on arbitrary graphs, in particular separation algorithms have received only little attention. In this study we describe new separation and lifting procedures for the cut polytope on general graphs. These procedures exploit algorithmic and structural results known for the cut polytope on complete graphs to generate valid, and sometimes facet defining, inequalities for the cut polytope on arbitrary graphs in a cutting plane framework. We report computational results on a set of well-established benchmark problems.
Using graph products we present an O(vertical bar V vertical bar E-2 vertical bar vertical bar + vertical bar V vertical bar(3) log vertical bar V vertical bar) separation algorithm for the nonsimple 1-wheel inequalit...
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Using graph products we present an O(vertical bar V vertical bar E-2 vertical bar vertical bar + vertical bar V vertical bar(3) log vertical bar V vertical bar) separation algorithm for the nonsimple 1-wheel inequalities by Cheng and Cunningham (1997) of the stable set polytope, which is faster than their O(vertical bar V vertical bar(4)) algorithm. There are two ingredients for our algorithm. The main improvement stems from a reduction of the separation problem to multiple shortest path problems in an auxiliary graph having only 6 vertical bar V vertical bar vertices and 9 vertical bar E vertical bar arcs, thereby preserving low sparsity. Then Johnson's algorithm can be applied to the auxiliary graph of same sparsity as the original one. In contrast, Cheng and Cunningham's auxiliary graph is by construction dense, vertical bar E vertical bar = O((vertical bar V vertical bar(2))), so application of Johnson's algorithm provides no large improvement. (C) 2014 Elsevier B.V. All rights reserved.
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