检索结果-内蒙古大学图书馆

Passenger-centered vulnerability assessment of railway networks

TRANSPORTATION RESEARCH PART B-METHODOLOGICAL 2020年 136卷 30-61页

作者： Szymula, Christopher Besinovic, Nikola Delft Univ Technol Dept Transport & Planning Delft Netherlands Tech Univ Dresden Friedrich List Fac Transportat & Traff Sci Dresden Germany

The performance and behaviour of critical infrastructure in case of disruptions is an important topic and we are still lacking of insights. Due to disruptions, infrastructure becomes unavailable and may force the trains and passengers to adapt. In this paper, we introduce a problem of railway network vulnerability from the perspective of passenger flows and train operations. We propose a new Railway Network Vulnerability Model (RNVM) to assess the vulnerability of the system by finding the critical combination of links, which cause the most adverse consequences to passengers and trains. To solve this challenging problem, we present a RNVM framework, which combines two heuristics based on column and row generation with mixed integer linear programming, to efficiently model alternative passenger flows and infrastructure constraints. The developed framework provides the critical combination of links, the corresponding passenger flows, train routes and timetables. We demonstrate the performance of the RNVM framework on the real-world instance of a part of the Dutch railway network. The results show that the RNVM framework can efficiently reassign passenger flows and reroute trains during disruptions. The results also reveal that the critical links are highly demand dependent rather than a static feature of the networks topology. Finally, the computation times remain small when increasing the number of disrupted links as well as the size of the passenger demand, which allows fast and efficient network vulnerability assessment. (C) 2020 The Authors. Published by Elsevier Ltd.

关键词： Railway networks Vulnerability Passenger flows mixed integer linear programming Column generation Row generation Resilience Optimization Public transport

来源：评论

学校读者我要写书评

暂无评论

Stochastic Multi-Fidelity Scheduling of Flexibility Reserve for Energy Storage

引用

IEEE TRANSACTIONS ON SUSTAINABLE ENERGY 2020年第3期11卷 1438-1450页

作者： Khatami, Roohallah Parvania, Masood Univ Utah Dept Elect & Comp Engn Salt Lake City UT 84112 USA

This paper proposes a continuous-time two-stage stochastic optimization model for multi-fidelity co-optimization of energy and flexibility reserve provided by generating units and energy storage (ES) devices in day-ahead operation. The flexibility reserve, defined as a single continuous-time trajectory that combines the balancing and ramping reserves, not only supplies the energy deviation but also the ramping requirements of load and renewable generation in power systems operation. The proposed model co-optimizes decision variables with different modeling fidelity, where the energy and flexibility reserve schedules are modeled and optimized by Bernstein polynomials of different degrees to match the flexibility requirements of load and renewable generation in day-ahead and real-time operation stages. Numerical studies, conducted on the IEEE reliability test system with the load and solar data of California ISO, highlight the benefits of the proposed stochastic multi-fidelity model over traditional discrete-time models in efficient utilization of ES flexibility to supply the energy and ramping requirements of the net-load and avoid scarcity events.

关键词： Trajectory Load modeling Stochastic processes Real-time systems Optimization Power systems Mathematical model Energy storage multi-fidelity modeling stochastic optimization continuous-time unit commitment flexibility reserve mixed integer linear programming

来源：评论

学校读者我要写书评

暂无评论

Resilient Service Embedding in IoT Networks

引用

IEEE ACCESS 2020年 8卷 123571-123584页

作者： Al-Shammari, Haider Qays Lawey, Ahmed Q. El-Gorashi, Taisir E. H. Elmirghani, Jaafar M. H. Univ Leeds Sch Elect & Elect Engn Leeds LS2 9JT W Yorkshire England

The Internet of Things (IoT) can support a significant number of services including those in smart homes and the automation of industries and public utilities. However, the growth of these deployments has posed a significant challenge especially in terms of how to build such deployments in a highly resilient manner. The IoT devices are prone to unpredicted failures and cyber-attacks, i.e. various types of damage, unreliable wireless connections, limited transmission power, computing ability, and storage space. Thus resilience is essential in IoT networks and in the services they support. In this paper, we introduce a new approach to resilience in IoT service embedding, based on traffic splitting. Our study assesses the power consumption associated with the services embedded and the data delivery time. The results are compared to recent approaches in resilience including redundancy and replication approaches. We constructed an optimization model whose goal is to determine the optimum physical resources to be used to embed the IoT virtual topology, where the latter is derived from a business process (BP). The embedding process makes use of the service-oriented architecture (SOA) paradigm. The physical resources of interest include IoT links and devices. The model made use of mixed integer linear programming (MILP) with an objective function that aimed to minimize both the total power consumption and the traffic latency. The optimization results show that the power consumption is reduced and the data delivery time is reduced in the service embedding approach where the proposed traffic splitting approach is employed resulting in the selection of energy efficient nodes and routes in the IoT network. Our methods resulted in up to 35% power saving compared to current methods and reduced the average traffic latency by up to 37% by selecting energy-efficient nodes and routes in IoT networks and by optimizing traffic flow to minimize latency.

关键词： Energy efficiency Internet of Things mixed integer linear programming queuing resilience smart buildings service-oriented architecture virtualization

来源：评论

学校读者我要写书评

暂无评论

Optimization of the integration among traditional fossil fuels, clean energies, renewable sources, and energy storages: An MILP model for the coupled electric power, hydraulic, and natural gas systems

引用

COMPUTERS & INDUSTRIAL ENGINEERING 2020年 139卷

作者： Alvarez, Gonzalo E. Marcovecchio, Marian G. Aguirre, Pio A. INGAR CONICET UTN Inst Desarrollo & Diseno Santa Fe Argentina UNL Santa Fe Argentina

This paper presents a mixed integer linear programming (MILP) formulation to optimize the Security Constrained Unit Commitment problem, integrating three areas: electrical, hydraulic, and natural gas. The model considers thermal generation from natural gas units and other fossil fuel units, hydraulic generation, pumped storage units, hydraulic head effects for the generation and pumping modes, power flow transmission constraints, natural gas supply and transportation, gas flows in single pipelines and pipelines with compressors, and line-pack for gas pipelines. The original model is hard to solve due to nonconvexities and nonlinearities of several constraints, but with the application of correct linearization techniques, accurate MILP models can be efficiently obtained and solved. The proposed MILP model differs from most of other approaches available in the literature in that it applies to several types of power generation, and includes a large number of real characteristics of the integrated system. A modified IEEE 31-bus with 2 pumped stations and 7-node natural gas system is presented to illustrate the effectiveness of the proposed model;test cases are solved by commercial package Gurobi. Test results indicate that the proposed approach provides feasible solutions with convenient CPU times. The obtained results are discussed and analyzed through simple graphs.

关键词： mixed integer linear programming Security Constrained Unit Commitment Energy conversion and storage Integrated energy systems Renewable and clean energy penetration

来源：评论

学校读者我要写书评

暂无评论

The two-echelon city logistics system with on-street satellites

引用

COMPUTERS & INDUSTRIAL ENGINEERING 2020年 139卷

作者： Li, Hongqi Liu, Yinying Chen, Kaihang Lin, Qingfeng Beihang Univ Sch Transportat Sci & Engn 37 Xueyuan Rd Beijing 100191 Peoples R China

In the two-echelon city logistics system, satellites enable cargo transshipment. Considering on-street satellite phenomena in city logistics practices and the concept of road space sharing between delivery operations and city traffic, we introduce the two-echelon city logistics system with on-street satellites (2E-CLS-OS). The 2E-CLS-OS uses time windows and satellite transshipment constraints to make routes of each of the two echelons interacting. At various time windows of on-street satellites, the real-time transshipment capacity needed by the transshipment operation is constrained by the permitted maximal transshipment capacity and the occupied transshipment capacity. The mathematical formulation for the 2E-CLS-OS is developed. The variable neighborhood search (VNS) heuristic is provided, based on the initial solution constructed by the savings-based heuristic (CW). The model formulation and the VNS are tested by using 20 randomly-generated small-scale instances. The VNS is used to solve 33 realistic instances with up to 30 on-street satellites and 900 customers. The economic difference between the electric vehicles and diesel ones on the second echelon and the impact of varying the truck capacity and the electric tricycle capacity are experimentally analyzed.

关键词： City logistics Two-echelon On-street satellite Real-time transshipment capacity mixed integer linear programming Variable neighborhood search

来源：评论

学校读者我要写书评

暂无评论

Optimal Design of Isolated Mini-Grids with Deterministic Methods: Matching Predictive Operating Strategies with Low Computational Requirements

引用

ENERGIES 2020年第16期13卷

作者： Micangeli, Andrea Fioriti, Davide Cherubini, Paolo Duenas-Martinez, Pablo Sapienza Univ Rome Dept Mech & Aerosp Engn DIMA Via Eudossiana 18 I-00184 Rome Italy Univ Pisa Dept Energy Syst Terr & Costruct Engn DESTEC I-56122 Pisa Italy MIT MIT Energy Initiat 77 Massachusetts Ave Cambridge MA 02139 USA

The lack of electricity access is increasingly concentrated in rural areas of developing countries, in which mini-grids are often a suitable solution;however, given the high risks, it is crucial to minimize costs. This paper aims at analyzing existing methodologies for the optimal design of mini-grids combined with different operating strategies. Typical system operations, like the load-following (LFS) and cycle charging (CCS) strategies, are compared with the more demanding predictive strategies based on mixed-integer linear programming (MILP). The problem is formulated and solved with Particle Swarm Optimization (PSO), so to simulate traditional and predictive operating strategies. Two reformulations based on the proposed Search Space Update are also detailed and compared with the so-called one-shot MILP model, which is able to con-jointly optimize both the design and the operation of the system, in order to reduce computational requirements with the predictive strategy. The results, tailored with data from a rural mini-grid in Kenya, highlight that heuristic methodologies can perform better than the traditional MILP approach, both in terms of optimality and computational time, especially when advanced operating strategies are considered. Conventional operating strategies (LFS or CCS) appear to be sub-optimal, but require very little computational requirements, which makes them suitable for preliminary designs.

关键词： isolated hybrid system microgrids mixed integer linear programming off-grid energy system Search Space Update (SSU)

来源：评论

学校读者我要写书评

暂无评论

Wind Power with Energy Storage Arbitrage in Day-ahead Market by a Stochastic MILP Approach

引用

LOGIC JOURNAL OF THE IGPL 2020年第4期28卷 570-582页

作者： Gomes, I. L. R. Melicio, R. Mendes, V. M. F. Pousinho, H. M., I Univ Evora Dept Fis Escola Ciencias & Tecnol P-7000645 Evora Portugal Univ Evora Inst Ciencias Terra ICT P-7000645 Evora Portugal Univ Lisbon Inst Super Tecn IDMEC P-1049001 Lisbon Portugal Inst Super Engn Lisboa Dept Elect Engn & Automat P-1959007 Lisbon Portugal Univ Beira Interior Electromechatron Syst Res Ctr CISE P-6201001 Covilha Portugal

This paper is about a support information management system for a wind power (WP) producer having an energy storage system (ESS) and participating in a day-ahead electricity market. Energy storage can play not only a leading role in mitigation of the effect of uncertainty faced by a WP producer, but also allow for conversion of wind energy into electric energy to be stored and then released at favourable hours. This storage provides capability for arbitrage, allowing an increase on profit of a WP producer, but must be supported by a convenient problem formulation. The formulation proposed for the support information management system is based on an approach of stochasticity written as a mixed integer linear programming problem. WP and market prices are considered as stochastic processes represented by a set of scenarios. The charging/discharging of the ESS are considered dependent on scenarios of market prices and on scenarios of WP. The effectiveness of the proposed formulation is tested by comparison of case studies using data from the Iberian Electricity Market. The comparison is in favour of the proposed consideration of stochasticity.

关键词： Electricity markets energy storage mixed integer linear programming stochastic optimization wind power

来源：评论

学校读者我要写书评

暂无评论

A modified genetic algorithm for non-emergency outpatient appointment scheduling with highly demanded medical services considering patient priorities

引用

COMPUTERS & INDUSTRIAL ENGINEERING 2020年 139卷

作者： Alizadeh, Reza Rezaeian, Javad Abedi, Mehdi Chiong, Raymond Mazandaran Univ Sci & Technol Dept Ind Engn POB 734 Babol Sar Mazandaran Iran Univ Newcastle Sch Elect Engn & Comp Callaghan NSW 2308 Australia

This paper presents an optimization problem concerning the booking of non-emergency outpatient appointments, where a single machine (device) and limited medical staff are supposed to fulfill the medical requirements of a large number of waiting patients. A new mixed integer linear programming model is formulated, characterized by two main features: (1) the method applied to calculate the duration of every single appointment is based on patients' particular therapy requirements and doctors' operating speeds, where the duration of the appointments may be different;and (2) taking the priorities of patients into consideration as a key factor of scheduling in the form of the times they prefer to be booked. The proposed model is solved and evaluated using an exact solver on several small-scale numerical examples, and the optimal solutions show that the model is well-designed and accurate. For instances of larger scale, a genetic algorithm (GA) is used to solve them. The performance of the GA is analyzed by comparing it to the exact method using a set of defined examples. Results indicate that the GA performs satisfactorily within reasonable computational time.

关键词： Appointment scheduling Operations research in health services Non-emergency outpatients mixed integer linear programming Genetic algorithm

来源：评论

学校读者我要写书评

暂无评论

A branch-and-cutapproach and alternative formulations for the traveling salesman problem with drone

引用

NETWORKS 2020年第2期76卷 164-186页

作者： Schermer, Daniel Moeini, Mahdi Wendt, Oliver Tech Univ Kaiserslautern Business Informat Syst & Operat Res BISOR Gottlieb Daimler Str D-67663 Kaiserslautern Germany

In this paper, we are interested in studying thetraveling salesman problem with drone(TSP-D). Given a set of customers and a truck that is equipped with a single drone, the TSP-D asks that all customers are served exactly once and minimal delivery time is achieved. We provide two compact mixed integer linear programming formulations that can be used to address instances with up to 10 customer within a few seconds. Notably, we introduce a third formulation for the TSP-D with an exponential number of constraints. The latter formulation is suitable to be solved by a branch-and-cut algorithm. Indeed, this approach can be used to find optimal solutions for several instances with up to 20 customers within 1 hour, thus challenging the current state-of-the-art in solving the TSP-D. A detailed numerical study provides an in-depth comparison on the effectiveness of the proposed formulations. Moreover, we reveal further details on the operational characteristics of a drone-assisted delivery system. By using three different sets of benchmark instances, consideration is given to various assumptions that affect, for example, technological drone parameters and the impact of distance metrics.

关键词： branch-and-cut drones last-mile delivery logistics mixed integer linear programming traveling salesman problem

来源：评论

学校读者我要写书评

暂无评论

Conflict-free en-route operations with horizontal resolution manoeuvers using a heuristic algorithm

引用

AERONAUTICAL JOURNAL 2020年第1275期124卷 767-785页

作者： Cecen, R. K. Cetek, C. Anadolu Univ Eskisehir Turkey Eskisehir Tech Univ Eskisehir Turkey

Aircraft conflict resolution is an important part of air traffic control operations. This study presents a mixed integer linear programming model (MILP) using a space discretisation technique to deal with aircraft conflict resolutions in en-route flight operations. The purpose of space discretisation is to concentrate on only the significant points of the airspace. The model integrates the multi entry point approach with an airspeed adjustment technique in the horizontal plane. The model aims to generate conflict-free trajectories while minimising the total changes in entry points and airspeed values. A new heuristic algorithm was developed due to the complexity of the problem. The computational results demonstrated that the proposed approach resolved aircraft conflicts for 450 different traffic scenarios in less than a minute. Considerable fuel savings were achieved with no significant increase in delay or flight time compared to conventional vectoring techniques in a fixed entry point airspace structure.

关键词： aircraft conflict resolution mixed integer linear programming heuristic algorithm air traffic flow management

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：