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SIGNAL PROCESSING 2003年第9期83卷 1839-1858页

作者： Kämpke, T FAW D-89081 Ulm Germany

Discrete functions over a continuous domain are approximated by discrete functions with fewer levels. These quantizations are endowed with different types of constraints such as monotonicity and variational constraints. Quantization functions exactly or approximately minimize the squared error to a given discrete function. Exact algorithms are derived from dynamic programming with finite horizon. All algorithms have polynomial run time. (C) 2003 Elsevier B.V. All rights reserved.

关键词： constrained optimization dynamic programming labeling algorithm minimum square errors

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The fastest itinerary in time-dependent decentralized travel information systems

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JOURNAL OF COMBINATORIAL OPTIMIZATION 2006年第3期12卷 167-185页

作者： Wang, Jinchang Kaempke, Thomas Richard Stockton Coll New Jersey Pomona NJ 08232 USA Res Inst Appl Knowledge Proc N D-89081 Ulm Germany

A travel information system (TIS) provides customers with information about transportation, transfers, and routings. A decentralized TIS is composed of autonomous subsystems and a central computer, where local subsystems have full control of their data and there is not a complete database in the central computer about the entire TIS. The transportation vehicles are scheduled. A travel itinerary from one spot to another contains the travel path and the schedule of transportations. The approach presented in this paper is for the central computer to identify the fastest itinerary across autonomous subsystems, based on the incomplete local information provided by the independent subsystems.

关键词： distributed computing shortest path problem fastest path problem labeling algorithm

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An efficient algorithm for automatic classification and centromere detection in G-band human chromosome image using band distance feature

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JOURNAL OF INTELLIGENT & FUZZY SYSTEMS 2021年第6期40卷 11463-11474页

作者： Kumar, P. Saravana Vasuki, S. Kalasalingam Inst Technol Dept ECE Krishnankoil Tamil Nadu India Velammal Coll Engn & Technol Dept ECE Viraganur Tamil Nadu India

In chromosome analysis, centromere is an essential component. By analyzing centromere, genetic disorder can be identified easily. In this paper, automatic classification and centromere detection in human chromosome image using Band Distance Feature is proposed. Initially the microscopic image of G-band chromosome is preprocessed in order to remove the blobs. Then, the image is segmented using labelling algorithm and the endpoints are calculated. Now, the overlapping chromosomes are removed when the number of end points is greater than two. The non-overlapped chromosomes are straightened using Reversible Projection algorithm. From the straightened chromosome band distance feature is calculated. The extracted features are given to the ANN classifier to identify the class of chromosome and to calculate the centromere. From the experimental results, it is observed that the proposed method is superior to the traditional method.

关键词： Artificial neural networks chromosome classification labeling algorithm straightening algorithm

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A multi-vehicle covering tour problem with speed optimization

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NETWORKS 2022年第2期79卷 119-142页

作者： Margolis, Joshua T. Song, Yongjia Mason, Scott J. Clemson Univ Dept Ind Engn Clemson SC 29634 USA

A multi-vehicle covering tour problem with speed optimization, we aim to construct a set of maximal coverage routes for a fleet of vehicles that serve (observe) a set of secondary sites, given a fixed time schedule and coverage requirements. We develop an exact solution approach using a branch-and-price framework with a label-correcting algorithm and a set of innovative dominance rules to solve the resulting pricing problem. We also develop a two-stage heuristic capable of finding effective initial solutions. In addition, we consider practical extensions to the model by incorporating risk thresholds, energy capacities, and time windows. To validate our proposed solution approaches, we perform an extensive set of numerical experiments. Numerical results show the computational advantage of our proposed solution approaches compared with a state-of-the-art commercial solver.

关键词： branch‐ and‐ price algorithm covering tour labeling algorithm heuristic speed optimization target surveillance vehicle routing

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The Migratory Beekeeping Routing Problem: Model and an Exact algorithm

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INFORMS JOURNAL ON COMPUTING 2021年第1期33卷 319-335页

作者： Ma, Zu-Jun Yang, Fei Dai, Ying Shen, Zuo-Jun Max Southwest Jiaotong Univ Sch Econ & Management Chengdu 610031 Peoples R China Univ Calif Berkeley Dept Ind Engn & Operat Res Berkeley CA 94720 USA Univ Calif Berkeley Dept Civil & Environm Engn Berkeley CA 94720 USA

Apiculture has gained worldwide interest because of its contributions to economic incomes and environmental conservation. In view of these, migratory beekeeping, as a high-yielding technique, is extensively adopted. However, because of the lack of an overall routing plan, beekeepers who follow the experiential migratory routes frequently encounter unexpected detours and suffer losses when faced with problems such as those related to nectar source capacities and the production of bee products. The migratory beekeeping routing problem (MBRP) is proposed based on the practical background of the commercial apiculture industry to optimize the global revenue for beekeepers by comprehensively considering nectar source allocation, migration, production and sales of bee products, and corresponding time decisions. The MBRP is a new variant of the vehicle routing problem but with significantly different production time decisions at the vertices (i.e., nectar sources). That is, only the overlaps between residence durations and flowering periods generate production benefits. Different sales visits cause different gains from the same products;in turn, these lead to different production time decisions at previously visited nectar source locations and even change the visits for production. To overcome the difficulty resulting from the complicated time decisions, we utilize the Dantizig-Wolfe decomposition method and propose a revised labeling algorithm for the pricing subproblems. The tests, performed on instances and a real-world case, demonstrate that the column generation method with the revised labeling algorithm is efficient for solving the MBRP. Compared with traditional routes, a more efficient overall routing schedule for migratory beekeepers is proposed. Summary of Contribution. Based on the practical background of commercial apiculture industry, this paper proposes a new type of routing problem named the migratory beekeeping routing problem (MBRP), which incorporates the

关键词： migratory beekeeping vehicle routing production decision timing decision Dantzig-Wolfe decomposition labeling algorithm

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Determining Type II sensitivity ranges of the fractional assignment problem

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OPERATIONS RESEARCH LETTERS 2011年第1期39卷 67-73页

作者： Lin, Chi-Jen Ta Hwa Inst Technol Dept Ind Engn & Management Cyong Lin 307 Hsin Chu County Taiwan

This paper proposes iterative labeling algorithms to determine the Type II sensitivity ranges of the fractional assignment problem. Unlike the traditional sensitivity range which keeps the current optimal basis remaining optimal, the Type II sensitivity range is the range that keeps the current optimal assignment remaining optimal. Focusing only on the non-degenerate basic variables makes the Type II sensitivity range more practical. Three cases of perturbation, each with two kinds, are discussed. An example is presented to demonstrate the proposed algorithms. (C) 2010 Elsevier B.V. All rights reserved.

关键词： Assignment problem Fractional programming Linear programming Sensitivity analysis Degeneracy labeling algorithm

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Branch-and-Cut-and-Price for the Vehicle Routing Problem with Time Windows and Convex Node Costs

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TRANSPORTATION SCIENCE 2019年第5期53卷 1409-1426页

作者： He, Qie Irnich, Stefan Song, Yongjia Univ Minnesota Dept Ind & Syst Engn Minneapolis MN 55455 USA Johannes Gutenberg Univ Mainz Gutenberg Sch Management & Econ D-55128 Mainz Germany Clemson Univ Dept Ind Engn Clemson SC 29634 USA

Two critical yet frequently conflicting objectives for logistics and transportation service companies are improving customer satisfaction and reducing transportation cost. In particular, given a network of customer requests with preferred service times, it is very challenging to find vehicle routes and service schedules simultaneously that respect all operating constraints and minimize the total transportation and customers' inconvenience costs. In this paper, we introduce the vehicle routing problem with time windows and convex node costs (VRPTW-CNC), in which we model each customer's inconvenience cost as a convex function of the service start time at that customer. The VRPTW-CNC combines and extends both the standard vehicle muting problem with time windows and some previous results on the optimal service scheduling problem over a fixed route. We propose a branch-and-cut-and-price algorithm to solve the VRPTW-CNC with general convex inconvenience cost functions. To solve the pricing problem, our labeling algorithm only generates labels that possibly lead to optimal schedule times over a route, which significantly improves the effectiveness of pricing. Extensive computational results demonstrate the effectiveness of our approach.

关键词： vehicle routing problem branch-and-cut-and-price labeling algorithm convex node costs integrated routing and scheduling

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Type II sensitivity analysis of cost coefficients in the degenerate transportation problem

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EUROPEAN JOURNAL OF OPERATIONAL RESEARCH 2013年第2期227卷 293-300页

作者： Ma, Kang-Ting Lin, Chi-Jen Wen, Ue-Pyng Natl Tsing Hua Univ Dept Ind Engn & Engn Management Hsinchu Taiwan Ta Hua Univ Sci & Technol Dept Ind Engn & Management Hsinchu Taiwan

This paper focuses on sensitivity analysis of the degenerate transportation problem (DTP) when perturbation occurs on one cost coefficient. The conventional Type I sensitivity analysis of the transportation problem (TP) determines the perturbation ranges for the invariant optimal basis. Due to different degenerate optimal basic solutions yielding different Type I ranges, the Type I range is misleading for the DTP. Type II sensitivity analysis, which determines the perturbation ranges for the invariant shipping pattern, is more practical for the DTP. However, it is too tedious to obtain Type II ranges by enumerating all optimal basic solutions and all primal optimal basic solutions while getting the union of each corresponding Type I ranges. Here, we propose two labeling algorithms to determine the Type II ranges of the cost coefficient. Besides, three lemmas are provided for obtaining the upper bound or lower bound of the Type II ranges of the cost coefficient directly under specific conditions of the DTP. A numerical example is given to demonstrate the procedure of the proposed labeling algorithms and computational results have been provided. (C) 2013 Elsevier B.V. All rights reserved.

关键词： Transportation Degeneracy labeling algorithm Sensitivity analysis Shipping pattern

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Variable Fixing for Two-Arc Sequences in Branch-Price-and-Cut algorithms on Path-Based Models

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TRANSPORTATION SCIENCE 2020年第5期54卷 1170-1188页

作者： Desaulniers, Guy Gschwind, Timo Irnich, Stefan Polytech Montreal GERAD Montreal PQ H3T 1J4 Canada Polytech Montreal Dept Math & Ind Engn Montreal PQ H3T 1J4 Canada Johannes Gutenberg Univ Mainz Gutenberg Sch Management & Econ D-55128 Mainz Germany

Variable fixing by reduced costs is a popular technique for accelerating the solution process of mixed-integer linear programs. For vehicle-routing problems solved by branch-price-and-cut algorithms, it is possible to fix to zero the variables associated with all routes containing at least one arc from a subset of arcs determined according to the dual solution of a linear relaxation. This is equivalent to removing these arcs from the network used to generate the routes. In this paper, we extend this technique to routes containing sequences of two arcs. Such sequences or their arcs cannot be removed directly from the network because routes traversing only one arc of a sequence might still be allowed. For some of the most common vehicle-routing problems, we show how this issue can be overcome by modifying the route-generation labeling algorithm in order to remove indirectly these sequences from the network. The proposed acceleration strategy is tested on benchmark instances of the vehicle-routing problem with time windows (VRPTW) and four variants of the electric VRPTW. The computational results show that it yields a significant speedup, especially for the most difficult instances.

关键词： integer programming branch price and cut variable fixing vehicle routing labeling algorithm

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Optimizing flow rates in a queueing network with side constraints

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EUROPEAN JOURNAL OF OPERATIONAL RESEARCH 1996年第3期88卷 586-591页

作者： Pourbabai, B Blanc, JPC Schouten, FAV TILBURG UNIV DEPT ECONOMETR5000 LE TILBURGNETHERLANDS UNIV MARYLAND DEPT MECH ENGNCOLLEGE PKMD 20742

In this paper, modified versions of the classical deterministic maximum flow and minimum cost network flow problems are presented in a stochastic queueing environment. In the maximum flow network model, the throughput rate in the network is maximized such that for each are of the network the resulting probability of finding congestion along that are in excess of a desirable threshold does not exceed an acceptable value. In the minimum cost network flow model, the minimum cost routing of a flow of given magnitude is determined under the same type of constraints on the arcs. After proper transformations, these models are solved by Ford and Fulkerson's labeling algorithm and out-of-kilter algorithm, respectively.

关键词： queueing network stochastic optimization labeling algorithm out-of-kilter algorithm

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