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Hybrid vns-LP algorithm for online optimal coordination of directional overcurrent relays

IET GENERATION TRANSMISSION & DISTRIBUTION 2020年第23期14卷 5447-5455页

作者： Damchi, Yaser Dolatabadi, Mohammad Shahrood Univ Technol Fac Elect Engn & Robot Shahrood Iran Vali E Asr Univ Rafsanjan Dept Math Rafsanjan Iran

Optimal coordination of directional overcurrent relays (DOCRs) in interconnected power systems is a highly constrained, non-convex and non-linear optimisation problem. In this study, use of a series of linear programming (LP) problems in a variable neighbourhood search (vns) framework is proposed, in which pickup current settings can be considered either as continuous or discrete variables. Therefore, the proposed hybrid algorithm (vns-LP) is suitable for coordination problem-solving in a network with different types of DOCRs. Furthermore, two versions of the vns algorithm are proposed, the first of which is very easy to implement, while, the other is somewhat more sophisticated, and at the same time much faster and possibly suitable for online coordination in smart grids applications. One advantage of the second algorithm is that it relies only on elementary arithmetic and requires low RAM, which makes it implementable in any low-level programming environment. This, in turn, can increase the interoperability, which is of crucial importance when automating tasks. The efficiency of the proposed algorithm was investigated in several test systems. Numerical results indicate that the two proposed approaches outperform the previous methods. Moreover, the coordination problem is solved in a reasonably short time using a faster approach.

关键词： smart power grids power system interconnection optimisation overcurrent protection relay protection search problems power system protection online optimal coordination directional overcurrent relays DOCR interconnected power systems nonconvex optimisation problem nonlinear optimisation problem linear programming problems variable neighbourhood search framework pickup current settings continuous variables discrete variables coordination problem-solving vns algorithm online coordination smart grids applications low-level programming environment hybrid vns-LP algorithm vns framework elementary arithmetic RAM

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Application of an improved whale optimization algorithm in time-optimal trajectory planning for manipulators

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MATHEMATICAL BIOSCIENCES AND ENGINEERING 2023年第9期20卷 16304-16329页

作者： Du, Juan Hou, Jie Wang, Heyang Chen, Zhi Taiyuan Univ Sci & Technol Sch Mech Engn Taiyuan 030024 Peoples R China

To address the issues of unstable, non-uniform and inefficient motion trajectories in traditional manipulator systems, this paper proposes an improved whale optimization algorithm for time-optimal trajectory planning. First, an inertia weight factor is introduced into the surrounding prey and bubble-net attack formulas of the whale optimization algorithm. The value is controlled using reinforcement learning techniques to enhance the global search capability of the algorithm. Additionally, the variable neighborhood search algorithm is incorporated to improve the local optimization capability. The proposed whale optimization algorithm is compared with several commonly used optimization algorithms, demonstrating its superior performance. Finally, the proposed whale optimization algorithm is employed for trajectory planning and is shown to be able to produce smooth and continuous manipulation trajectories and achieve higher work efficiency.

关键词： trajectory planning time-optimal whale optimization algorithm reinforcement learning vns algorithm

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A mathematical model for location of temporary relief centers and dynamic routing of aerial rescue vehicles

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COMPUTERS & INDUSTRIAL ENGINEERING 2019年 131卷 227-241页

作者： Alinaghian, Mandi Aghaie, Mohammad Sabbagh, Mohammad S. Isfahan Univ Technol Dept Ind & Syst Engn 17 ESteghlal AveDaneshgah St Esfahan *** Iran

This paper presents a new mathematical model for location of temporary relief centers and dynamic routing of aerial rescue vehicles distributing basic supplies in relief operations. The objective function of the proposed model minimizes the arrival time at the last designated temporary relief center. The proposed model seeks to locate the temporary relief centers in a way that all affected areas get covered by at least one temporary relief center. Considering the importance of quick action amid a post-disaster environment with characteristics such as uncertain demand for relief supplies, inaccurate information regarding victims, aftershocks, and extensively damaged road networks, in the proposed model, location and level of demand are considered to be dynamic, and relief supplies are assumed to be distributed by aerial transport vehicles. According to NP-Hardness of proposed problem, in this paper an improved hybrid metaheuristic algorithm based on scatter search combined with variable neighborhood search is presented. To evaluate the performance of the proposed algorithm, it is tested and compared with an exact method, basic scatter search and genetic algorithm. Results show the good performance of the proposed algorithm.

关键词： Dynamic routing Covering tour Hybrid scatter search algorithm Genetic algorithm vns algorithm

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Joint optimization of train timetabling and rolling stock circulation planning: A novel flexible train composition mode

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TRANSPORTATION RESEARCH PART B-METHODOLOGICAL 2022年 162卷 352-385页

作者： Zhou, Housheng Qi, Jianguo Yang, Lixing Shi, Jungang Pan, Hanchuan Gao, Yuan Beijing Jiaotong Univ State Key Lab Rail Traff Control & Safety Beijing 100044 Peoples R China East China Jiaotong Univ Coll Transportat & Logist Nanchang 330013 Peoples R China Shanghai Univ Engn Sci Sch Urban Rail Transportat Shanghai 201620 Peoples R China Beijing Inst Technol Sch Management & Econ Beijing 100081 Peoples R China

The tidal traffic phenomenon is one of the most prominent problems on some metro lines, where a large number of commuters during the peak hours might cause the non-equilibrium spatial-temporal distribution of passenger flow. In order to better match the passenger demand, this study proposes a mixed-integer linear programming (MILP) model to jointly optimize the train timetable and rolling stock circulation plan, in which the flexible train composition mode is particularly taken into account by allowing rolling stocks to change their compositions through uncoupling/coupling operations at the both ends of the focused metro line. To solve the model, a customized heuristic algorithm based on the variable neighborhood search (vns) is developed to quickly generate high-quality solutions. Based on a small example and the real-world data from Beijing metro Batong line, two sets of numerical experiments are conducted to verify the effectiveness and applicability of the proposed methodology. The computation results show that in comparison to the fixed train composition mode, the proposed approaches can bring 17.1% reduction of operation costs in morning peak periods, with no increase of passenger waiting time.

关键词： Train timetable Flexible train composition mode Rolling stock circulation plan vns algorithm

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Parallel machine scheduling with linearly increasing energy consumption cost

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ANNALS OF MATHEMATICS AND ARTIFICIAL INTELLIGENCE 2023年第2-3期91卷 239-258页

作者： Hu, Chaoming Lu, Shaojun Kong, Min Liu, Xinbao Pardalos, Panos M. Hefei Univ Technol Sch Management Hefei Anhui Peoples R China Minist Educ Key Lab Proc Optimizat & Intelligent Decis Making Hefei Anhui Peoples R China Anhui Normal Univ Sch Econ & Management Wuhu Peoples R China Univ Florida Dept Ind & Syst Engn Ctr Appl Optimizat Gainesville FL 32611 USA

This paper deals with a parallel machine scheduling problem with linearly increasing energy consumption cost. Maintenance activities are considered in the problem. After maintenance, the machine energy consumption cost returns to the normal level. Thus, an important decision is how to determine a reasonable number of maintenance activities to enable a significant tradeoff between the maintenance cost and the energy consumption cost. We define the jobs processed between two adjacent maintenance activities as a batch since the job processing cannot be interrupted. A further decision is how to batch the jobs. To solve the investigated problem, we first study a special case where there is only one single machine. A heuristic approach is proposed to solve the single machine scheduling problem. Then, we present a variable neighborhood search (vns) algorithm for general cases, where the heuristic approach for the single machine case is intergrated. Extensive computational experiments are conducted and the results show that the proposed vns algorithm is superior to artificial bee colony (ABC) algorithm, genetic algorithm (GA), ant colony optimization (ACO) algorithm, Tabu search (TS)algorithm, and greedy randomized adaptive search procedure (GRASP) algorithm.

关键词： Production scheduling Energy consumption cost Maintenance vns algorithm

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Variable Neighborhood Search for Automatic Density-Based Clustering

Variable Neighborhood Search for Automatic Density-Based Clu...

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International Conference on Mathematics and Information Technology (ICMIT)

作者： Boudane, Fatima Berrichi, Ali Univ MHamed Bougara Boumerdes LIMOSE Lab Dept Comp Sci Boumerdes Algeria

ISBN: (纸本)9781538632697

Clustering is a well studied data mining task. Many effective clustering algorithms have been proposed over the years. However, most of them suffer from the problems of arbitrary shaped data. Although, density-based clustering algorithms can identify clusters of arbitrary shapes and handle noise (or outliers) very effectively, one difficulty is that it is hard to choose parameter values, such as the density threshold. In this paper, we propose a variable neighborhood search heuristic to handle arbitrary shaped data automatically, without using any parameter values. This heuristic has been tested on seven selected datasets from the literature. It appears that it produces high quality clustering. Using a clustering validation index as fitness criteria, experiments show that our approach achieves better performance compared with six other clustering methods from the literature.

关键词： clustering vns algorithm density-based clustering neighborhood

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Design of Dynamic Vehicle Routing System Based on Online Map Service 13

Design of Dynamic Vehicle Routing System Based on Online Map...

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13th International Conference on Service Systems and Service Management (ICSSSM)

作者： Li, Rui Qi, Mingyao Cheng, Chun Lai, Weiwei Guangdong Power Grid Huizhou Power Supply Bur Huizhou 516001 Peoples R China Tsinghua Univ Grad Sch Shenzhen Res Ctr Modern Logist Shenzhen 518055 Peoples R China

ISBN: (纸本)9781509028429

Most vehicle routing systems use local map data, and can only handle static customer demand and transportation information. This paper presents a solution to develop dynamic vehicle routing system based on online map service. Google maps API is adopted to construct map related functions like route display, address geocoding, distance matrix and so on. A Variable Neighborhood Search algorithm is designed to calculate the dynamic vehicle routing problem. Strategies in response to realtime customer demand and real-time traffic information are introduced to dynamically adjust vehicle routes. A real-world application has proven that this technology can improve the efficiency of transport decision and save logistics cost to a large extent.

关键词： dynamic vehicle routing online map service Google maps API vns algorithm GIS

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Variable Neighborhood Search-based Resource Allocation for Vehicle-to-Everything Communications 27

Variable Neighborhood Search-based Resource Allocation for V...

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27th International Symposium on Real-Time Distributed Computing (ISORC)

作者： Brahmi, Ibtissem Elleuch, Souhir Hamdi, Monia Zarai, Faouzi Univ Sfax NTSCOM Res Unit ENETCOM Sfax Tunisia Univ Gabes Res Team Intelligent Machines BP W 6072 Gabes Tunisia

ISBN: (纸本)9798350371291;9798350371284

Third Generation Partnership Project (3GPP) introduced Vehicle-to-Everything (V2X) in Long Term Evolution (LTE) Release 14 and Release 15. The present work aimed to investigate the resource allocation problem for V2X communications. To this end, we proposed applying the Variable Neighborhood Search (vns) algorithm to solve the resource allocation problem. The proposed method aims to maximize the total throughput in the system while maintaining a minimum latency and reliability for both Cellular User Equipment (CUEs) and Vehicle User Equipment (VUEs). To verify the effectiveness of the proposed method, the vns-based resource allocation scheme was compared to two other schemes;the first is based on the Particle Swarm Optimization (PSO) algorithm, and the second on the Ant Colony Optimization (ACO) algorithm. The simulation was carried out using MATLAB software. The obtained results prove the performance of the proposed scheme in terms of resource allocation for V2X communications. The performance gains of the proposed approach demonstrate its feasibility and utility for V2X communications.

关键词： V2X Communications Resource Allocation vns algorithm Radio Resource Management

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Minimizing the total tardiness and the total carbon emissions in the permutation flow shop scheduling problem

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COMPUTERS & OPERATIONS RESEARCH 2022年 138卷 105604-105604页

作者： Saber, Reza Ghorbani Ranjbar, Mohammad Ferdowsi Univ Mashhad Fac Engn Dept Ind Engn Mashhad Razavi Khorasan Iran

In this paper, we consider the permutation flow shop scheduling problem and aim to minimize the total tardiness as well as the total carbon emissions. We present a formulation of the problem through a mixed-integer programming model. To solve the problem, we develop a multi-objective decomposition-based heuristic (MODBH) algorithm, working based on job insertion, as well as a multi-objective vns algorithm. Furthermore, a multi-objective iterated greedy algorithm is utilized to validate the efficiency of the developed methods. Using extensive computational experiments, we indicate that the MODBH algorithm has a significant superiority to the other developed solution approaches. Furthermore, the multi-objective vns algorithm shows better performance than the multi-objective iterated greedy algorithm.

关键词： Flow shop scheduling Total tardiness Total carbon emissions Heuristic algorithm Multi-objective optimization vns algorithm

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Optimal resource allocation and routing in robotic mobile fulfillment systems

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COMPUTERS & OPERATIONS RESEARCH 2024年 165卷

作者： Hashemi, Saeedeh Ranjbar, Mohammad Ferdowsi Univ Mashhad Fac Engn Dept Ind Engn Mashhad Iran

This paper addresses a combinatorial optimization problem in the context of a robotic mobile fulfillment system deployed in a warehouse that consists of movable racks, a picker, and a fleet of mobile robots. The objective is to efficiently prepare a set of orders with specified due dates by bringing the racks to a picking station in a sequential manner, where the picker selects the required products for the open orders, namely the orders that are being processed simultaneously. The picking station has a limited capacity for processing of open orders. Our goal is to minimize the total travel times of the robots and the delays in fulfilling orders. To achieve this, several decision variables need to be determined, including order sequencing, rack allocation, rack scheduling, and mobile robot routing. We formulate the problem as a mixed integer programming model and devise a heuristic algorithm grounded in decomposition principles to address the problem across two distinct phases. Additionally, we introduce two variable neighborhood search (vns) algorithms tailored to resolve each respective phase within the aforementioned heuristic framework. The performance of the proposed solution approaches is evaluated and compared using two sets of randomly generated test instances, encompassing small-size and large-size instances. Furthermore, we conduct an analysis to examine the influence of key parameters on the objective function value.

关键词： Scheduling Routing Robot mobile fulfillment systems Heuristic algorithm vns algorithm

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