检索结果-内蒙古大学图书馆

A novel model for transfer synchronization in transit networks and a Lagrangian-based heuristic solution method

EUROPEAN JOURNAL OF OPERATIONAL RESEARCH 2024年第1期317卷 76-91页

作者： Ansarilari, Zahra Bodur, Merve Shalaby, Amer Univ Toronto Dept Civil & Mineral Engn Toronto ON Canada Univ Edinburgh Sch Math Edinburgh Scotland

To realize the benefits of network connectivity in transfer -based transit networks, it is critical to minimize transfer disutility for passengers by synchronizing timetables of intersecting routes. We propose a mixedinteger linear programming timetable synchronization model that incorporates new features, such as dwell time determination and vehicle capacity consideration, which have been largely overlooked in the literature at the scheduling stage. We introduce a new concept of pre -planned holding time, called transfer buffer time, to reduce the transfer waiting time, particularly for transfers to low -frequency routes, while taking into account the penalty of extra in -vehicle time for onboard passengers and the possible consequences on headway regularity of a route. We develop a Lagrangian relaxation -based heuristic to obtain high -quality solutions efficiently for large instances. Our experiments on instances with up to 12 transfer nodes in the City of Toronto, with a mixture of low- and high -frequency routes, illustrate the potential benefits of the proposed model over the state of the art. The results indicate that incorporating transfer buffer time, dwell time determination, and vehicle capacity consideration improves model outcomes considerably, also demonstrating the computational efficiency of our Lagrangian-based solution method.

关键词： Transfer synchronization Bus dwell time determination Vehicle capacity mixed integer linear programming Lagrangian relaxation

来源：评论

学校读者我要写书评

暂无评论

Ego-Network Segmentation via (Weighted) Jaccard Median

引用

IEEE TRANSACTIONS ON KNOWLEDGE AND DATA ENGINEERING 2024年第9期36卷 4646-4663页

作者： Zhong, Haodi Loukides, Grigorios Conte, Alessio Pissis, Solon P. Xidian Univ Sch Comp Sci & Technol Xian 710071 Peoples R China Kings Coll London London WC2R2LS England Univ Pisa I-6126 Pisa Italy CWI NL-1098XG Amsterdam Netherlands Vrije Univ NL-1081HV Amsterdam Netherlands

An ego-network is a graph representing the interactions of a node (ego) with its neighbors and the interactions among those neighbors. A sequence of ego-networks having the same ego can thus model the evolution of these interactions over time. We introduce the problem of segmenting a sequence of ego-networks into k segments. Each segment is represented by a summary network, and the goal is to minimize the total loss of representing k segments by k summaries. The main challenge is to construct a summary with minimum loss. To address it, we employ the Jaccard Median (JM) problem, for which, however, no effective and efficient algorithms are known. We develop several algorithms for JM: (I) an exact algorithm, based on mixed integer linear programming;(II) exact and approximation polynomial-time algorithms for minimizing an upper bound of the objective function of JM;and (III) efficient heuristics. We also study a generalization of the segmentation problem, in which there may be multiple edges between a pair of nodes in an ego-network, and develop a series of algorithms (exact algorithms and heuristics) for it, based on a more general problem than JM, called Weighted Jaccard Median (WJM). By building upon the above results, we design algorithms for segmenting a sequence of ego-networks. Extensive experiments show that our algorithms produce (near)-optimal solutions to JM or to WJM and that they substantially outperform state-of-the-art methods which can be employed for ego-network segmentation.

关键词： Approximation algorithms Heuristic algorithms Social networking (online) Upper bound mixed integer linear programming linear programming Synthetic data Ego-network jaccard median segmentation

来源：评论

学校读者我要写书评

暂无评论

Extensive Model and Matheuristic Algorithm for the Train Platforming Problem with Two-Train-Capacity Tracks: A Case Study of Prague Central Station

引用

TRANSPORTATION RESEARCH RECORD 2024年第4期2678卷 131-154页

作者： Ozer, Emine Akyol Bulicek, Josef Sarac, Tugba Eskisehir Tech Univ Ind Engn Dept Eskisehir Turkiye Univ Pardubice Dept Transport Technol & Control Pardubice Czech Republic Eskisehir Osmangazi Univ Ind Engn Dept Eskisehir Turkiye

This paper provides a deeper insight into the train platforming problem (TPP). Many studies have focused on different versions of train scheduling and routing problems, and most of them assume that the platform track's capacity is one train. However, especially in busy and complex railway stations, most platform tracks are divided into two parts, allowing two trains to simultaneously share the same platform track for passenger boarding/alighting. This results in more efficient train assignment to the platform tracks. In addition, consideration of the track capacity makes the problem more difficult because directions of trains are problematic. Motivated by this challenge, we consider the TPP with two-train-capacity tracks. We first describe the problem in detail and then propose a mixed-integer programming model. The objective of the considered problem is to minimize the total weighted train delays, which are defined as the difference between the departure times calculated by the mathematical model (M1) and the scheduled departure times of the trains in the timetable. Because of the NP-hard nature of the problem, the proposed M1 may not find feasible solutions for large-size problems. Thus, a matheuristic algorithm (MA) is developed to solve large-size problems. We used randomly generated test problems to demonstrate the performance of the proposed M1 and MA. Experimental results showed that MA outperforms M1 in both solution quality and solution time. Additionally, a case study was conducted at the central station of Prague, Czechia.

关键词： matheuristic algorithm passenger rail transportation mixed integer linear programming platform track assignment railway optimization models transportation planning analysis and application train platforming problem

来源：评论

学校读者我要写书评

暂无评论

Hierarchical Framework for Space Exploration Campaign Schedule Optimization

引用

JOURNAL OF SPACECRAFT AND ROCKETS 2024年第5期61卷 1146-1164页

作者： Gollins, Nicholas Ho, Koki Georgia Inst Technol Daniel Guggenheim Sch Aerosp Engn Atlanta GA 30332 USA

Space exploration plans are becoming increasingly complex as public agencies and private companies target deep-space locations, such as cislunar space and beyond, which require long-duration missions and many supporting systems and payloads. Optimizing multimission exploration campaigns is challenging due to the large number of required launches as well as their sequencing and compatibility requirements, making conventional space logistics formulations unscalable. To tackle this challenge, this paper proposes an alternative approach that leverages a two-level hierarchical optimization algorithm: an evolutionary algorithm is used to explore the campaign scheduling solution space, and each of the solutions is then evaluated using a time-expanded multicommodity flow mixed-integer linear program. A number of case studies, focusing on the Artemis lunar exploration program, demonstrate how the method can be used to analyze potential campaign architectures. The method enables a potential mission planner to study the sensitivity of a campaign to program-level parameters such as logistics vehicle availability and performance, payload launch windows, and in situ resource utilization infrastructure efficiency.

关键词： Space Exploration and Technology Optimization Algorithm Space Logistics Models Lunar Exploration mixed integer linear programming Evolutionary Algorithm Propellant Mass Fraction Multi Objective Genetic Algorithm

来源：评论

学校读者我要写书评

暂无评论

An iterated local search for a multi-period orienteering problem arising in a car patrolling application

引用

NETWORKS 2024年第1期83卷 153-168页

作者： Correa, Victor Hugo Vidigal Dong, Hang Iori, Manuel dos Santos, Andre Gustavo Yagiura, Mutsunori Zucchi, Giorgio Univ Fed Vicosa Dept Informat Vicosa Brazil Univ Modena & Reggio Emilia Dept Sci & Methods Engn Reggio Emilia Italy Nagoya Univ Grad Sch Informat Nagoya Japan Univ Modena & Reggio Emilia Sch Doctorate E4E Modena Italy Coopservice Scpa R&D Dept Reggio Emilia Italy

This paper addresses a real-world multi-period orienteering problem arising in a large Italian company that needs to patrol an area in order to provide security services to a set of customers. Each customer requires different services on a weekly basis. Some services are mandatory, while others are optional. It might be impossible to perform all optional services, and each of them is assigned a score when performed. The challenge is to determine a set of routes, one per day, that maximizes a weighted sum of the total collected score and total working time, while meeting several operational constraints, including hard time windows, maximum riding time, minimum number of services performed, and minimum time between two consecutive visits for the same service at the same customer. To solve the problem, we propose an iterated local search that invokes at each iteration an inner variable neighborhood descent procedure. Computational tests performed on a large number of real-world instances prove that the developed algorithm is very efficient, and finds in a short time solutions that are consistently better than those produced by a mathematical model, and those in use at the company.

关键词： car patrolling problem iterated local search mixed integer linear programming orienteering problem variable neighborhood descent

来源：评论

学校读者我要写书评

暂无评论

Production scheduling problem with assembly flow shop systems: mathematical optimisation models

引用

INTERNATIONAL JOURNAL OF PRODUCTION RESEARCH 2024年第7期62卷 2483-2498页

作者： Santana, Jose Renathoda de Silva Fuchigami, Helio Yochihiro Univ Fed Goias Fac Sci & Technol Aparecida De Goiania Brazil Univ Fed Sao Carlos Dept Prod Engn Sao Carlos Brazil Univ Fed Goias Fac Sci & Technol St Barao doRio Branco Aparecida De Goiania GO Brazil

This work presents four mixed integer linear programming (MILP) models for the assembly flow shop problem in order to minimize the makespan. This production environment has two stages: production and assembly. The first stage consists of different machines designed to manufacture parts of a product. The second stage is intended for a final assembly. The performance measure considered is highly essential for industries from different segments, as it focuses on the best use of the time available for production. Statistical analysis with different tools was used to assess the performance and efficiency of mathematical models, emphasizing the analysis of performance profiles. Results showed that mathematical models are efficient, and the position-based model presented the best results for small and large instances during computational experimentation. All mathematical models can be used as direct tools in decision-making for the production sequencing problem in the approached environment.

关键词： Assembly flow shop mixed integer linear programming scheduling makespan two-stage assembly

来源：评论

学校读者我要写书评

暂无评论

Bi-level Stochastic Optimization Model for Coordination of Transmission and Distribution Networks Considering Generic Resources

引用

JOURNAL OF ELECTRICAL ENGINEERING & TECHNOLOGY 2024年第2期19卷 961-976页

作者： Tamizkar, Roozbeh Moghaddam, Mahmoud Samiei Azarfar, Azita Abardeh, Mohamad Hoseini Vahedi, Mojtaba Islamic Azad Univ Dept Elect Engn Shahrood Branch Shahrood Iran Islamic Azad Univ Dept Elect Engn Damghan Branch Damghan Iran

In this paper, an optimization model for transmission and distribution network integration is proposed. The proposed model is a bi-level optimization model formulated as an upper and lower-level problem. The problem of unit commitment in the transmission network as the upper level problem with the aim of reducing operating costs and load shedding as a mixed integer linear programming model and the problem of optimal operation in the distribution network by considering renewable and non-renewable resources along with electric vehicle charging stations (EVCS), it has been considered as a linear model with the aim of reducing the cost of purchasing power from the transmission network and increasing the use of renewable energy and charging power of EVCS. According to the literature, the study gap can be seen in three key points;firstly, it is of great importance to provide a convex model that can guarantee global optimal solutions. The next point is related to the problem-solving time, according to the dimensions and number of variables and parameters in the problem of optimal coordination of the transmission and distribution network, providing a method to achieve global optimal solutions in the shortest time and the last point is related to the modeling of any number of distribution networks is integrated with the transmission network. To solve the proposed bi-level optimization problem, the method of rewriting the optimization problems using Karush-Kuhn-Tucker condition equations, which can model global optimal solutions as well as fast solution time and modeling a large number of distribution networks in the transmission network has been proposed. Several different networks have been considered for the validation of the proposed model and method, which proves the results obtained from the simulation of the efficiency of the proposed model and method in considering the coordinated operation of transmission and smart distribution networks. The results showed that the p

关键词： Coordination of transmission and distribution network Bi-level stochastic optimization Renewable energy mixed integer linear programming

来源：评论

学校读者我要写书评

暂无评论

A Combined Topology Formation and Rate Allocation Algorithm for Aeronautical Ad Hoc Networks

引用

IEEE TRANSACTIONS ON MOBILE COMPUTING 2024年第1期23卷 12-28页

作者： Megas, Vasileios Hoppe, Sandra Ozger, Mustafa Schupke, Dominic Cavdar, Cicek KTH Royal Inst Technol Sch Elect Engn & Comp Sci Stockholm 11428 Sweden Airbus D-85521 Munich Germany Nokia Strategy & Technol D-81541 Munich Germany Airbus Cent Res & Technol Commun Technol D-85521 Munich Germany

This paper addresses the problem of providing internet connectivity to aircraft flying above the ocean without using satellite connectivity given the lack of ground network infrastructure in the relevant oceanic areas. Is it possible to guarantee a minimum flow rate to each aircraft flying over an ocean by forming an aeronautical ad hoc network and connecting that network to internet via a set of limited number of ground base stations at the coast as anchor points? We formulated the problem as mixed-integer-linear programming (MILP) to maximize the number of aircraft with flow data rate above a certain threshold. Since this multi-commodity flow problem is at least NP-complete, we propose a two-phase heuristic algorithm to efficiently form topology and assign flows to each aircraft by maximizing the minimum flow. The performance of the heuristic algorithm is evaluated over the North Atlantic Corridor, heuristic performs only 8% less than the optimal result with low densities. In high network densities, the connectivity percentage changes from 70% to 40% under 75 Mbps data rate threshold. Furthermore, the connectivity percentage is investigated for different network parameters such as altitude and compared to upper and lower bounds and a baseline algorithm.

关键词： Topology formation rate allocation aerial networks ad-hoc networks direct air to ground communication air to air communication mixed integer linear programming aircraft connectivity

来源：评论

学校读者我要写书评

暂无评论

A cut-and-solve algorithm for virtual machine consolidation problem

引用

FUTURE GENERATION COMPUTER SYSTEMS-THE INTERNATIONAL JOURNAL OF ESCIENCE 2024年 154卷 359-372页

作者： Luo, Jiang-Yao Chen, Liang Chen, Wei-Kun Yuan, Jian-Hua Dai, Yu-Hong Beijing Univ Posts & Telecommun Sch Sci Beijing 100876 Peoples R China Chinese Acad Sci Acad Math & Syst Sci LSEC ICMSEC Beijing Peoples R China Beijing Inst Technol Sch Math & Stat Beijing Key Lab MCAACI Beijing 100081 Peoples R China Beijing Univ Posts & Telecommun Key Lab Math & Informat Networks Minist Educ Beijing 100876 Peoples R China

The virtual machine consolidation problem attempts to determine which servers to be activated, how to allocate virtual machines to the activated servers, and how to migrate virtual machines among servers such that the summation of activated, allocation, and migration costs is minimized subject to the resource constraints of the servers and other practical constraints. In this paper, we first propose a new mixed integer linear programming formulation for the virtual machine consolidation problem. We show that compared with existing formulations, the proposed formulation is much more compact in terms of smaller numbers of variables or constraints, which makes it suitable for solving large-scale problems. We then develop a cut-and-solve algorithm, a tree search algorithm to efficiently solve the virtual machine consolidation problem to optimality. The proposed cut-and-solve algorithm is based on a novel relaxation of the virtual machine consolidation problem that provides a stronger lower bound than the natural continuous relaxation of the virtual machine consolidation problem, making a smaller search tree. By extensive computational experiments, we show that (i) the proposed formulation significantly outperforms existing formulations in terms of solution efficiency;(ii) compared with standard mixed integer linear programming solvers, the proposed cut-and-solve algorithm is much more efficient;and (iii) compared with an existing heuristic algorithm, the proposed cut-and-solve algorithm is better able to balance workload distribution across servers and achieve higher resource utilization.

关键词： Cut-and-solve Cutting plane Exact algorithm mixed integer linear programming Virtual machine consolidation

来源：评论

学校读者我要写书评

暂无评论

Three network design problems for community energy storage

引用

NETWORKS 2024年第4期84卷 420-445页

作者： Ghaddar, Bissan Ljubic, Ivana Qiu, Yuying Western Univ Ivey Business Sch London ON Canada ESSEC Business Sch Cergy Pontoise France

In this article, we develop novel mathematical models to optimize utilization of community energy storage (CES) by clustering prosumers and consumers into energy sharing communities/microgrids in the context of a smart city. Three different microgrid configurations are modeled using a unifying mixed-integer linear programming formulation. These configurations represent three different business models, namely: the island model, the interconnected model, and the Energy Service Companies model. The proposed mathematical formulations determine the optimal households' aggregation as well as the location and sizing of CES. To overcome the computational challenges of treating operational decisions within a multi-period decision making framework, we also propose a decomposition approach to accelerate the computational time needed to solve larger instances. We conduct a case study based on real power consumption, power generation, and location network data from Cambridge, MA. Our mathematical models and the underlying algorithmic framework can be used in operational and strategic planning studies on smart grids to incentivize the communitarian distributed renewable energy generation and to improve the self-consumption and self-sufficiency of the energy sharing community. The models are also targeted to policymakers of smart cities, utility companies, and Energy Service Companies as the proposed models support decision making on renewable energy related projects investments.

关键词： community energy storage decentralized energy resources energy management system mixed integer linear programming OR in energy

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：