检索结果-内蒙古大学图书馆

A Branch-and-Price algorithm for the electric autonomous Dial-A-Ride Problem

TRANSPORTATION RESEARCH PART B-METHODOLOGICAL 2024年 186卷

作者： Su, Yue Dupin, Nicolas Parragh, Sophie N. Puchinger, Jakob Ecole Ponts ParisTech CERMICS F-77420 Champs Sur Marne France Univ Angers LERIA SFR MATHST F-49000 Angers France Johannes Kepler Univ Linz Inst Prod & Logist Management A-4040 Linz Austria EM Normandie Business Sch Metis Lab F-92110 Clichy France Univ Paris Saclay Cent Supelec Lab Genie Ind F-91190 Gif Sur Yvette France

The Electric Autonomous Dial -A -Ride Problem (E-ADARP) consists in scheduling a fleet of electric autonomous vehicles to provide ride -sharing services for customers that specify their origins and destinations. The E-ADARP considers the following perspectives: (i) a weightedsum objective that minimizes both total travel time and total excess user ride time;(ii) the employment of electric autonomous vehicles and a partial recharging policy. This paper presents the first labeling algorithm for a path -based formulation of the DARP/E-ADARP, where the main ingredient includes: (1) fragment -based representation of paths, (2) a novel approach that abstracts fragments to arcs while ensuring excess -user -ride -time optimality, (3) construction of a sparser new graph with the abstracted arcs, which is proven to preserve all feasible routes of the original graph, and (4) strong dominance rules and constant -time feasibility checks to compute the shortest paths efficiently. This labeling algorithm is then integrated into Branchand -Price (B&P) algorithms to solve the E-ADARP. In the computational experiments, the B&P algorithm achieves optimality in 71 out of 84 instances. Remarkably, among these instances, 50 were solved optimally at the root node without branching. We identify 26 new best solutions, improve 30 previously reported lower bounds, and provide 17 new lower bounds for large-scale instances with up to 8 vehicles and 96 requests. In total 42 new best solutions are generated on previously solved and unsolved instances. In addition, we analyze the impact of incorporating the total excess user ride time within the objectives and allowing unlimited visits to recharging stations. The following managerial insights are provided: (1) solving a weighted -sum objective function can significantly enhance the service quality, while still maintaining operational costs at nearly optimal levels, (2) the relaxation on charging visits allows us to solve all instances feasibly and

关键词： Dial-A-Ride Problem Electric autonomous vehicles (Excess-)user-ride-time optimal scheduling Branch-and-Price labeling algorithm

来源：评论

学校读者我要写书评

暂无评论

frvcpy: An Open-Source Solver for the Fixed Route Vehicle Charging Problem

引用

INFORMS JOURNAL ON COMPUTING 2021年第4期33卷 1277-1283页

作者： Kullman, Nicholas D. Froger, Aurelien Mendoza, Jorge E. Goodson, Justin C. Univ Tours Lab Fundamental & Appl Comp Sci LIFAT F-37200 Tours France Univ Bordeaux Inst Math Bordeaux Inria Bordeaux Sud Ouest F-33405 Talence France HEC Montreal Montreal PQ H3T 2A7 Canada Ctr Interuniv Rech Sur Reseaux Entreprise Logist Montreal PQ H3T 1J4 Canada St Louis Univ Richard A Chaifetz Sch Business St Louis MO 63103 USA

Electric vehicles offer a pathway to more sustainable transportation, but their adoption entails new challenges not faced by their petroleum-based counterparts. A difficult task in vehicle routing problems addressing these challenges is determining how to make good charging decisions for an electric vehicle traveling a given route. This is known as the fixed route vehicle charging problem. An exact and efficient algorithm for this task exists, but its implementation is sufficiently complex to deter researchers from adopting it. In this work we introduce frvcpy, an open-source Python package implementing this algorithm. Our aim with the package is to make it easier for researchers to solve electric vehicle routing problems, facilitating the development of optimization tools that may ultimately enable the mass adoption of electric vehicles.

关键词： electric vehicles vehicle routing open-source Python exact optimization labeling algorithm

来源：评论

学校读者我要写书评

暂无评论

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

引用

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

来源：评论

学校读者我要写书评

暂无评论

The Migratory Beekeeping Routing Problem: Model and an Exact algorithm

引用

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

来源：评论

学校读者我要写书评

暂无评论

A branch-and-price-and-cut algorithm for operating room scheduling under human resource constraints

引用

COMPUTERS & OPERATIONS RESEARCH 2023年第1期152卷

作者： Bargetto, Roberto Garaix, Thierry Xie, Xiaolan Univ Clermont Auvergne Mines St Etienne INP Clermont Auvergne CNRSUMR 6158 LIMOS F-42023 St Etienne 2 France Shanghai Jiao Tong Univ Shanghai Peoples R China

In this paper, we address an integrated operating room planning and scheduling problem that includes, with fine detail, constraints commonly encountered in practice (i.e., sequence, capacity and due date constraints) and for human resources other than surgeons, i.e., nurses. A new model of the sequence-dependent operating room cleaning times that arise because of surgeries with different infection levels is considered. To solve this difficult integrated planning and scheduling problem, we devise a branch-and-price-and-cut algorithm based on the time-indexed formulation of the problem. The basic column generation scheme relies on a label-correcting algorithm that we purposely developed for solving the pricing problems that are modeled as single operating room scheduling problems with time-dependent costs and sequence-dependent cleaning times. The pricing problems are strongly NP-Hard. The efficiency of the label-correcting algorithm is ensured by dominance rules among labels and by two algorithms for computing the upper and lower bound of labels. An effective cutting procedure, inspired by Benders' decomposition and based on duality theory for linear programming, is developed for tightening the linear relaxation of the problem. With instances from the literature and that we generated, we conduct a numerical study to demonstrate the computational effectiveness of the solution method.

关键词： Operating room scheduling Operations research in healthcare Column generation labeling algorithm Benders? cuts Branch-and-price-and-cut

来源：评论

学校读者我要写书评

暂无评论

Network Design with Service Requirements: Scaling-up the Size of Solvable Problems

引用

INFORMS JOURNAL ON COMPUTING 2022年第5期34卷 2571-2582页

作者： Gudapati, Naga V. C. Malaguti, Enrico Monaci, Michele Univ Bologna Dipartimento Ingn Energia Elettr & Informaz Gugli I-40136 Bologna Italy

characteristics of a network satisfying requirements on connectivity, capacity, and level-of-service. It finds applications in logistics and transportation, telecommunications, data sharing, energy distribution, and distributed computing. In multicommodity network design, one is required to design a network minimizing the installation cost of its arcs and the operational cost to serve a set of point-to-point connections. The definition of this prototypical problem was recently enriched by additional constraints imposing that each origin-destination of a connection is served by a single path satisfying one or more level-of-service requirements, thus defining the Network Design with Service Requirements. These constraints are crucial, for example, in telecommunications and computer networks to ensure reliable and low-latency communication. In this paper we provide a new formulation for the problem, where variables are associated with paths satisfying the end-to-end service requirements. We present a fast algorithm for enumerating all the exponentially many feasible paths, and when this is not viable, we provide a column generation scheme that is embedded into a branch-and-cut-and-price algorithm. Extensive computational experiments on a large set of instances show that our approach can move a step further in the solution of the network design with service requirements compared with the current state-of-the-art.

关键词： network design multicommodity flow service requirements branch-and-cut-and-price algorithm budget-constrained shortest path labeling algorithm

来源：评论

学校读者我要写书评

暂无评论

A column generation tailored to electric vehicle routing problem with nonlinear battery depreciation

引用

COMPUTERS & OPERATIONS RESEARCH 2022年 137卷 105527-105527页

作者： Zang, Yongsen Wang, Meiqin Qi, Mingyao Tsinghua Univ Dept Ind Engn Beijing 100084 Peoples R China Tsinghua Univ Shenzhen Int Grad Sch Res Ctr Modern Logist Shenzhen 518055 Peoples R China

Since the battery remains a significant cost component of electric vehicles (EVs), controlling the depreciation costs of EVs' batteries is of great importance, especially from the perspective of the electric vehicle routing problem (EVRP). However, most existing studies on the EVRP have not explicitly considered the battery depreciation in the cost function;instead, it has been treated as a linear function of an EV's travel distance or time. In fact, the depth-of-discharge (DOD) significantly affects the battery life and leads to a naturally nonlinear depreciation function, which can be used to calculate the battery life more accurately. In this paper, we adopt three battery depreciation methods to investigate and compare their influences on the EVRP with time windows (EVRPTW): (1) a nonlinear function of DOD;(2) a linear function of charge-discharge cycles;and (3) a linear function of total traveling distance. The first method is mainly studied, and the remaining two methods are verified as comparative analyses. Meanwhile, both full and partial charge policies are considered to formulate the problem. By combining the charging policies and battery depreciation methods, four mixed -integer programming models are formulated, aiming to minimize the total cost. To pursue exact solutions in acceptable computing time, a column generation algorithm (CG) that relies on four tailored labeling algorithms (LAs) is designed. The LAs are used to accelerate the calculation speed of the pricing problem. The most considerable difficulty of solving pricing problems lies in the complex endogenous relationships among recharging time, drivers' waiting time, battery state-of-charge (SOC), battery depreciation, battery rated capacity, and driving distance. The LAs need to find a tradeoff among them and generate the shortest paths. Given this, we design specific and elaborate resource extension functions (REFs) for the four models, respectively, which is an extension to Desaulniers et al.

关键词： Vehicle routing Time window Electric vehicle Battery depreciation Partial recharge Column generation labeling algorithm

来源：评论

学校读者我要写书评

暂无评论

Exact and heuristic dynamic programming algorithms for the traveling salesman problem with flexible time windows

引用

OPTIMIZATION LETTERS 2020年第3期14卷 579-609页

作者： Fachini, Ramon Faganello Armentano, Vinicius Amaral Univ Estadual Campinas Fac Engn Eletr & Comp BR-13083852 Campinas SP Brazil

This article proposes extensions of exact and heuristic dynamic programming algorithms for the traveling salesman problem with flexible time windows, which are a limited enlargement of the generally referred to as hard time windows. The service of a customer can be started before or after the hard time window at a penalty cost. The addressed problem thus requires the determination of a sequence of customers and their respective service start times in order to minimize the sum of traveling cost with earliness and lateness cost. Computational tests are conducted on a variety of symmetric and asymmetric instances proposed in the literature, and the advantages of flexible windows are stressed.

关键词： Traveling salesman problem Flexible time windows Dynamic programming labeling algorithm

来源：评论

学校读者我要写书评

暂无评论

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

引用

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

来源：评论

学校读者我要写书评

暂无评论

Improved formulations and algorithmic components for the electric vehicle routing problem with nonlinear charging functions

引用

COMPUTERS & OPERATIONS RESEARCH 2019年 104卷 256-294页

作者： Froger, Aurelien Mendoza, Jorge E. Jabali, Ola Laporte, Gilbert Univ Tours LIFAT EA 6300 CNRS ROOT ERL CNRS 7002 Tours France HEC Montreal Montreal PQ Canada Politecn Milan Dipartimento Elettron Informaz & Bioingn Milan Italy HEC Montreal Canada Res Chair Distribut Management Montreal PQ Canada

Electric vehicle routing problems (E-VRPs) are receiving growing attention from the operations research community. Electric vehicles differ substantially from internal combustion engine vehicles, the main difference lying in their limited autonomy, which can be recovered at charging stations. Modeling the charging functions is a focal point of E-VRPs. Most of the research has focused on constant or linear charging functions. The E-VRP with nonlinear charging function (E-VRP-NL) was recently introduced to account for the more realistic nonlinear relationship between the time spent charging and the amount of energy charged. We propose two new formulations for this problem. We first develop an arc-based tracking of the time and the state of charge which, according to our experiments, outperforms the classical node based tracking of these values. To avoid replicating the charging stations nodes, as done for both node and arc based formulations, we also introduce a path-based model. We develop an algorithm to generate a tractable number of these paths. This path-based model outperforms the classical models in our experiments. We also propose a new model, a heuristic, and an exact labeling algorithm for the problem of finding the optimal charging decisions for a given route. Extensive computational results show that charging decisions considerably impact the quality of the E-VRP-NL solutions. Indeed, we improve 23 out of 120 best known E-VRP-NL solutions by solely revising the charging decisions. (C) 2018 Elsevier Ltd. All rights reserved.

关键词： Vehicle routing problem Electric vehicle routing problem with nonlinear charging function Mixed integer linear programming labeling 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：