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A matheuristic approach with nonlinear subproblems for large-scale packing of ellipsoids

EUROPEAN JOURNAL OF OPERATIONAL RESEARCH 2019年第2期272卷 447-464页

作者： Birgin, E. G. Lobato, R. D. Univ Sao Paulo Inst Math & Stat Dept Comp Sci Rua Matao 1010 BR-05508090 Sao Paulo SP Brazil Univ Estadual Campinas Dept Appl Math Inst Math Stat & Sci Comp Rua Sergio Buarque de Holanda 651 BR-13083859 Campinas SP Brazil

The problem of packing ellipsoids in the three-dimensional space is considered in the present work. The proposed approach combines heuristic techniques with the resolution of recently introduced nonlinear programming models in order to construct solutions with a large number of ellipsoids. The introduced approach is able to pack identical and non-identical ellipsoids within a variety of containers. Moreover, it allows the inclusion of additional positioning constraints. This fact makes the proposed approach suitable for constructing large-scale solutions with specific positioning constraints in which density may not be the main issue. Numerical experiments illustrate that the introduced approach delivers good quality solutions with a computational cost that scales linearly with the number of ellipsoids;and solutions with more than a million ellipsoids are exhibited. (C) 2018 Elsevier B.V. All rights reserved.

关键词： Packing Ellipsoids nonlinear programming Algorithms Matheuristic

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Energy Efficiency of Distributed Antenna Systems With Wireless Power Transfer

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IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS 2019年第1期37卷 89-99页

作者： Huang, Yuwen Liu, Yuan Li, Geoffrey Ye South China Univ Technol Sch Elect & Informat Engn Guangzhou 510641 Guangdong Peoples R China Chinese Univ Hong Kong Dept Informat Engn Hong Kong Peoples R China Georgia Inst Technol Sch Elect & Comp Engn Atlanta GA 30332 USA

In this paper, we study energy-efficient resource allocation in distributed antenna system with wireless power transfer, where time-division multiple access is adopted for downlink multiuser information transmission. In particular, when a user is scheduled to receive information, other users harvest energy at the same time using the same radio-frequency signal. We consider two types of energy efficiency (EE) metrics: user-centric EE (UC-EE) and network-centric EE (NC-EE). Our goal is to maximize the UC-EE and NC-EE, respectively, by optimizing the transmission time and power subject to the energy harvesting requirements of the users. For both UC-EE and NC-EE maximization problems, we transform the nonconvex problems into equivalently tractable problems by using suitable mathematical tools and then develop iterative algorithms to find the globally optimal solutions. Simulation results demonstrate the superiority of the proposed methods compared with the benchmark schemes.

关键词： Distributed antenna systems (DAS) energy efficiency (EE) wireless power transfer nonlinear programming

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Comparison of Various Guidance Strategies to Achieve Time Constraints in Optimal Descents

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2019年第7期42卷 1612-1621页

作者： Dalmau, Ramon Prats, Xavier Verhoeven, Ronald Bussink, Frank Heesbeen, Bart Tech Univ Catalonia UPC Dept Phys C Esteve Terradas 5Bldg C3Off 121 Castelldefels 08860 Spain Tech Univ Catalonia UPC Dept Phys C Esteve Terradas 5Bldg C3Off 104 Castelldefels 08860 Spain Netherlands Aerosp Ctr NLR Cockpit & Flight Operat Div POB 90502 NL-1059 CM Amsterdam Netherlands

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Joint service improvement and content placement for cache-enabled heterogeneous cellular networks

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IET SIGNAL PROCESSING 2019年第3期13卷 253-261页

作者： Dai, Haibo Wang, Yi Zhou, Tianqing Yang, Luxi Nanjing Univ Posts & Telecommun Sch Internet Things Nanjing 210003 Peoples R China Zhengzhou Univ Aeronaut Sch Elect & Commun Engn Zhengzhou 450046 Henan Peoples R China East China Jiaotong Univ Sch Informat Engn Nanchang 330013 Jiangxi Peoples R China Southeast Univ Sch Informat Sci & Engn Nanjing 210096 Jiangsu Peoples R China

Caching popular contents in the storage of base stations (BSs) has emerged as a promising solution for reducing the transmission latency and providing extra-high throughput. This study tackles the optimal trade-off problem between the sum of effective rates and backhaul saving through joint service improvement and content placement in cache-enabled heterogeneous cellular networks while guaranteeing the quality-of-service requirements of all user terminals (UTs) and backhaul traffic constraints of all BSs. However, there exists an intractable issue of mixing the integer nature into the feasible region in the nonlinear optimisation problem. To this end, the authors decompose the optimisation problem into three subproblems by alternately fixing two of three classes of variables (i.e. UT association, power control, and content placement). Aiming at these subproblems, they, respectively, convert them into the tractable forms and propose the corresponding algorithms. By combining them, they propose a three-tier iterative algorithm for jointly optimising UT association and cache placement. Finally, numerical results have verified the effectiveness of proposed schemes.

关键词： cellular radio telecommunication traffic iterative methods quality of service nonlinear programming integer programming joint service improvement content placement cache-enabled heterogeneous cellular networks base stations transmission latency reduction extra-high throughput optimal trade-off problem sum-of-effective rates backhaul saving quality-of-service requirements user terminals backhaul traffic constraints nonlinear optimisation problem UT association power control three-tier iterative algorithm

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Application of improved invasive weed optimization technique for optimally setting directional overcurrent relays in power systems

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APPLIED SOFT COMPUTING 2019年 79卷 1-13页

作者： Srinivas, S. T. P. Swarup, Shanti K. Indian Inst Technol Madras Dept Elect Engn Chennai 600036 Tamil Nadu India

This paper aims to study the application of a heuristic optimization technique namely, Invasive Weed Optimization (IWO) technique for optimal protection coordination in power systems. The optimal relay coordination problem is formulated as a nonlinear constrained optimization, which is solved using Improved IWO (IIWO). The proposed IIWO algorithm modifies the standard deviation expression of the weed population. The simulation results show that IIWO has faster and better convergence compared with standard IWO. To further improve the computational efficiency, a hybrid IIWO method is also proposed which is obtained by defining sequential quadratic programming (SQP) as a subroutine in IIWO for searching local solutions, thus eliminate weaker weeds in the colonization process. The proposed techniques are tested on both the 9-bus test system and IEEE- 30 bus systems and the performance is compared. Relay coordination algorithm is developed in MATLAB, and the results are found to be effective and reliable. (C) 2019 Elsevier B.V. All rights reserved.

关键词： Directional overcurrent relays Heuristic programming Invasive weed optimization nonlinear programming Optimal relay coordination

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Liner Ship Routing with Speed and Fleet Size Optimization

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KSCE JOURNAL OF CIVIL ENGINEERING 2019年第3期23卷 1341-1350页

作者： Kim, Hwa-Joong Son, Dong-Hoon Yang, Woosuk Kim, Jae-Gon Inha Univ Asia Pacific Sch Logist Incheon 22212 South Korea Inha Univ Grad Sch Logist Incheon 22212 South Korea Inha Univ Jungseok Res Inst Incheon 22212 South Korea Incheon Natl Univ Dept Ind & Management Engn Incheon 22012 South Korea

The shipping route network design is a strategic decision issue for shipping lines because liner ships operate along routes and timetables published months ahead. This paper considers an Integrated Planning Problem (IPP) of determining the speed, route, and number of ships deployed (fleet size) of a ship type. The objective is to maximize a carrier's profit, which is the revenue minus Cargo Handling Charge (CHC), bunker consumption cost, port charge, cargo inventory cost and ship time cost. We present a nonlinear shortest-path model to represent the considered problem and suggest a Simulated Annealing (SA) algorithm with some analytic methods. Performance evaluation experiments demonstrate that the proposed algorithm works well for small test problems. A number of scenario analyses are further performed with the heuristic algorithm to investigate the effect of exogenous factors, including bunker price, chartering cost, revenue (sea freight rate) and ship size. The analysis results show that strategic decisions for determining the route, fleet size and ship speed can be affected by changes in the factors. The performance tests and scenario analyses show that the heuristic algorithm can be utilized as an efficient and effective planning tool for the liner service in both the current environment and feasible future situations.

关键词： ship speed routing fleet size nonlinear programming simulated annealing algorithm

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Distributed Strategy for Optimal Dispatch of Unbalanced Three-Phase Islanded Microgrids

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IEEE TRANSACTIONS ON SMART GRID 2019年第3期10卷 3210-3225页

作者： Vergara, Pedro P. Rey, Juan M. Shaker, Hamid R. Guerrero, Josep M. Jorgensen, Bo Norregaard da Silva, Luiz C. P. Univ Estadual Campinas Dept Syst & Energy BR-13083852 Campinas SP Brazil Univ Ind Santander Escuela Ingn Elect Elect & Telecomunicac Bucaramanga 680002 Colombia Univ Southern Denmark Ctr Energy Informat DK-5230 Odense Denmark Aalborg Univ Dept Energy Technol DK-9220 Aalborg Denmark

This paper presents a distributed strategy for the optimal dispatch of islanded microgrids, modeled as unbalanced three-phase electrical distribution systems. To set the dispatch of the distributed generation (DG) units, an optimal generation problem is stated and solved distributively based on primal-dual constrained decomposition and a first-order consensus protocol, where units can communicate only with their neighbors. Thus, convergence is guaranteed under the common convexity assumptions. The islanded microgrid operates with the standard hierarchical control scheme, where two control modes are considered for the DG units: a voltage control mode, with an active droop control loop, and a power control mode, which allows setting the output power in advance. To assess the effectiveness and flexibility of the proposed approach, simulations were performed in a 25-bus unbalanced three-phase microgrid. According to the obtained results, the proposed strategy achieves a lower cost solution when compared with a centralized approach based on a static droop framework, with a considerable reduction on the communication system complexity. Additionally, it corrects the mismatch between generation and consumption even during the execution of the optimization process, responding to changes in the load consumption, renewable generation, and unexpected faults in units.

关键词： Consensus algorithm distributed dispatch optimal power flow nonlinear programming three-phase microgrid

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Optimal control problem of multi-vehicle cooperative autonomous parking trajectory planning in a connected vehicle environment

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IET INTELLIGENT TRANSPORT SYSTEMS 2019年第11期13卷 1677-1685页

作者： Wu, Bing Qian, Lijun Lu, Meiling Qiu, Duoyang Liang, Haiqin Hefei Univ Technol Coll Automot & Transportat Engn Dept Vehicle Engn Hefei 230009 Anhui Peoples R China Nanjing Univ Aeronaut & Astronaut Coll Automat Engn Dept Elect Engn Nanjing 210016 Jiangsu Peoples R China

The development of intelligent network and intelligent vehicle technology makes it possible for multi-vehicle cooperative driving. In this study, the multi-vehicle cooperative autonomous parking condition is addressed by establishing a vehicle kinematics model combined with dynamic constraints and endpoint and collision avoidance constraints. The autonomous parking trajectory planning problem is transformed into an optimal control problem. The shortest parking completion time is set as the optimal cost function, and the optimal control problem is discretised by using the Gauss pseudo-spectral method. Then, the non-linear programming problem is solved. Moreover, an initial guess generation strategy is proposed, and the iteration method is used to solve the problem by adding collision avoidance constraints to the collision situation of the vehicle to improve the convergence and robustness of the problem. The simulation model is built in MATLAB/Simulink to simulate multi-vehicle cooperative autonomous parking under different working conditions. The simulation results show that the proposed method can solve the multi-vehicle cooperative autonomous parking trajectory planning problem uniformly and effectively. Compared with the traditional pseudo-spectral method, the proposed method has a faster convergence speed.

关键词： optimisation nonlinear programming path planning iterative methods optimal control mathematics computing mobile robots collision avoidance trajectory control linear programming optimal control problem connected vehicle environment intelligent vehicle technology autonomous parking condition vehicle kinematics model collision avoidance constraints autonomous parking trajectory planning problem shortest parking completion time optimal cost function nonlinear programming problem

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Optimal storage and loading zones within surface parking facilities for privately owned automated vehicles

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IET INTELLIGENT TRANSPORT SYSTEMS 2019年第12期13卷 1754-1760页

作者： Kong, You Le Vine, Scott Liu, Xiaobo Southwest Jiaotong Univ Sch Transportat & Logist Natl Engn Lab Integrated Transportat Big Data App 111 Erhuanlu Beiyiduan Chengdu 610031 Peoples R China Shanghai Maritime Univ Coll Transport & Commun 1550 Haigang Ave Shanghai 201306 Peoples R China SUNY Coll New Paltz Dept Geog New Paltz NY USA

There is much speculation about the prospective impacts of automated vehicles (AVs) on parking supply and behaviour, however the literature contains little quantitative evidence. In this study, we develop a mixed-integer non-linear optimisation (MINLP) model of revenue maximisation to design parking facility layouts for privately-owned automated cars that include separate vehicle-storage and drop-off/pick-up zones (DOPU, or alternatively termed "PUDO zones"). The control variable is the allocation of space between these two competing uses. The model balances between revenue derived from parking (including revenue during activity time) and costs associated with the range of AVs' parking and loading/unloading activities. Via numerical analysis of an archetypal shopping centre's parking facility, the authors demonstrate that the model responds intuitively to the stimulus of systematically varying the input parameters. This study is intended to provide an incremental advance to support researchers and practitioners tasked with quantifying the impacts of AVs on the parking system.

关键词： nonlinear programming integer programming mobile robots road traffic control design engineering surface parking facilities privately owned automated vehicles parking supply mixed-integer nonlinear optimisation revenue maximisation separate vehicle-storage control variable activity time archetypal shopping centre parking facility layout design AV parking optimal storage zones optimal loading zones

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Stochastic economic analysis of FACTS devices on contingent transmission networks using hybrid biogeography-based optimization

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ELECTRICAL ENGINEERING 2019年第3期101卷 829-843页

作者： Ghaemi, Sina Aghdam, Farid Hamzeh Safari, Amin Farrokhifar, Meisam Azarbaijan Shahid Madani Univ Dept Elect Engn Tabriz Iran Skolkovo Inst Sci & Technol Ctr Energy Sci & Technol Moscow Russia

Flexible AC transmission systems (FACTS) devices have advantages of enhancing AC system controllability and stability, increasing power transfer capability and relieving congestion. Finding the best sizing and siting of them is obligatory to obtain the maximum benefit. In this paper, the optimum planning is done for determining the suitable sizing and siting of the FACTS devices during their lifetime span. The proposed planning approach is implemented to the networks, which are suffering from the contingency to demonstrate that how proper sizing and siting of the FACTS devices are able to deal with the existing problems in such networks. In fact, the maximum social welfare, reducing load shedding cost and construction cost of the new branches besides of the technical issues such as voltage improvement are the main concerns of the present work. To accomplish these aims accurately and reduce the computation time, a hybrid approach, consisting of mathematical and heuristic methods, is proposed for solving the proposed planning problem. The mentioned algorithm is a combination of biogeography-based optimization (BBO) as a heuristic algorithm and nonlinear programming as a mathematical approach. Furthermore, since the stochastic natures of renewable energy sources and load variations contribute to the optimum decisions, the stochastic formulation has been considered in the planning problem using the efficient point estimation (2m + 1) scheme. Finally, the proposed planning approach is tested on different test systems, namely IEEE 14-bus, IEEE 57-bus and IEEE 300-bus, in order to verify its effectiveness from a different point of views.

关键词： Biogeography-based optimization (BBO) nonlinear programming FACTS Contingency management

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