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Integrated operation models with quay crane maintenance in a container terminal

OCEAN & COASTAL MANAGEMENT 2024年 251卷

作者： Wang, Tingsong Gao, Guangxu Wang, Kai Shi, Jia Shanghai Univ Sch Management Shanghai 200444 Peoples R China Wuhan Univ Econ & Management Sch Wuhan 430072 Peoples R China Shenzhen Univ Coll Management Shenzhen 518071 Peoples R China

This paper investigates an integrated optimization problem concerning berth allocation, quay crane assignment, and truck deployment in container terminals, with a specific focus on incorporating quay crane maintenance into the integrated models. A nonlinear integer programming model is proposed, and then a number of equivalent or relaxed models are developed to ease the model. To solve the model on large-scale instances, a SWO-GA is developed to provide a solution. Finally, a set of test instances are randomly generated to access the applicability of the proposed models and the efficiency of the algorithm. The results show that the SWO-GA can obtain a good solution with a small gap within a much shorter computation time than that of CPLEX. Quay crane maintenance significantly affects the operation plans and increases costs. The maintenance time step and the number of berths required for quay crane have a proportional impact on the total cost. It is also found that quay crane maintenance is of great concern for large-sized container terminals. The model and algorithm proposed in this paper provide important insights for operation managers.

关键词： Integrated operation models Quay crane maintenance non-linear mixed-integer programming SWO-GA

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Cost-optimal cloudlet placement frameworks over fiber-wireless access networks for low-latency applications

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JOURNAL OF NETWORK AND COMPUTER APPLICATIONS 2019年 138卷 27-38页

作者： Mondal, Sourav Das, Goutam Wong, Elaine Univ Melbourne Dept Elect & Elect Engn Melbourne Vic 3010 Australia Indian Inst Technol Kharagpur GS Sanyal Sch Telecommun Kharagpur 721302 W Bengal India

In the recent past, we have observed a trend that edge devices are increasingly accessing computational resources through the Internet, preferably via cloud computing technologies. However, cloud servers fail to meet the desired latency requirements of low-latency applications like augmented reality, cognitive assistance, and Tactile Internet applications, primarily due to the high-transmission latency from edge devices. This issue is resolved by augmenting cloud networks with a cloudlet enabled edge computing solution that creates a three-tier network topology. In this paper, we primarily focus on static cloudlet network planning problem and propose a hybrid cost-optimization framework for optimal cloudlet placement over existing passive optical access networks, subject to capacity and latency constraints. We formulate a mixed integer non-linear program to identify ideal cloudlet placement locations over urban, suburban and rural deployment scenarios. We show that the target latency requirement and the type of deployment scenario plays a major role in determining the amount of computational resources to be installed in the cloudlets. We also show that the percentage of the incremental energy budget of the access networks due to active cloudlet installation is under 18%. Overall, we show that the newly proposed hybrid cloudlet placement framework achieves the most cost optimal solution as compared to the field cloudlet placement framework.

关键词： Cloud computing Cloudlet Cost-minimization Low-latency non-linear mixed-integer programming Fiber-wireless access networks

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Supporting Low-Latency Applications through Hybrid Cost-Optimised Cloudlet Placement 20

Supporting Low-Latency Applications through Hybrid Cost-Opti...

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20th International Conference on Transparent Optical Networks (ICTON)

ISBN: (纸本)9781538666050

Low-latency applications such as augmented reality, cognitive assistance, and context-aware computation are better supported by augmenting cloud networks with cloudlet enabled edge computing solution. This overcomes the high-transmission latency arising from the edge devices in the access segment to cloud servers located in the core. In this talk, we will review our recently proposed hybrid cost-optimization framework for optimal cloudlet placement over existing passive optical access networks, subject to capacity and latency constraints. In our work, we formulate a mixed-integer non-linear program to identify ideal locations (either at the central office (CO), remote node (RN), or in the field) for cloudlet placement over three deployment areas of differing population densities. Our results point to the fact that the installation of more RN and CO-located cloudlets will yield an improved cost optimal solution than the installation of field cloudlets alone, and that the percentage of the incremental energy budget arising from the installation of cloudlets are low.

关键词： cloud computing cloudlets cost-optimization low-latency non-linear mixed-integer programming passive optical access network Tactile Internet

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CCOMPASSION: A Hybrid Cloudlet Placement Framework over Passive Optical Access Networks

CCOMPASSION: A Hybrid Cloudlet Placement Framework over Pass...

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37th IEEE Conference on Computer Communications (IEEE INFOCOM)

ISBN: (纸本)9781538641286

Cloud-based computing technology is one of the most significant technical advents of the last decade and extension of this facility towards access networks by aggregation of cloudlets is a step further. To fulfill the ravenous demand for computational resources entangled with the stringent latency requirements of computationally-heavy applications related to augmented reality, cognitive assistance and context-aware computation, installation of cloudlets near the access segment is a very promising solution because of its support for wide geographical network distribution, low latency, mobility and heterogeneity. In this paper, we propose a novel framework, Cloudlet Cost OptiMization over PASSIve Optical Network (CCOMPASSION), and formulate a nonlinear mixed-integer program to identify optimal cloudlet placement locations such that installation cost is minimized whilst meeting the capacity and latency constraints. Considering urban, suburban and rural scenarios as commonly used network deployment models, we investigate the feasibility of the proposed model over them and provide guidance on the overall cloudlet facility installation over optical access network. We also study the percentage of incremental energy budget in the presence of cloudlets of the existing network. The final results from our proposed model can be considered as fundamental cornerstones for network planning with hybrid cloudlet network architectures.

关键词： Cloudlet low latency non-linear mixed-integer programming optical access network

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Optimal solutions for the venezuelan unit commitment hydrothermal system

Optimal solutions for the venezuelan unit commitment hydroth...

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IEEE/PES Transmission and Distribution Conference and Exposition Latin America

作者： Piemonti, Carlos Bermudez, Juan Khodr, H. M. Alvarez, Manuel Power System Specialization Program Universidad Simón Bolívar Venezuela Department of Electrical Engineering Universidad Simón Bolívar Caracas Venezuela

ISBN: (纸本)9781424402878

This work is about different optimal solutions for the unit commitment problem in the Venezuelan hydrothermal power system, disregarding the transmission system. The centralized cost-based maximum net social benefit solution, the oligopoly solution and the unregulated monopoly solution are formulated and analyzed. The oligopoly is studied via Nash-Cournot equilibrium, obtained iteratively considering both price-maker and price-taker firms. The price-demand curves are created using a price-demand elasticity parameter. The hydro plants can be of the run-of-river type or can have a regulation period, like in the case of Guri. In latter case the future profit is represented by a fixed volume of water to be turbined in the day ahead. Since integer variable are necessary to simulate the shut-down, start-up process a mixed integer commercial programming application is employed.

关键词： unit commitment electrical market optimization non-linear mixed-integer programming

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Reactive power planning incorporating voltage stability

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INTERNATIONAL JOURNAL OF ELECTRICAL POWER & ENERGY SYSTEMS 2002年第3期24卷 185-200页

作者： Chattopadhyay, D Chakrabarti, BB Univ Canterbury Dept Management Energy Modeling Res Grp Christchurch 1 New Zealand

This paper addresses some of the modeling and economic issues pertaining to reactive power planning. We present a new VAR planning model, propose an efficient solution algorithm, and discuss the economic issues. A contingency constrained OPF-based model incorporating (static) voltage stability constraints is developed to analyze VAR support decisions. DICOPT++, a state-of-the-art non-linear mixed integer programming (MINLP) algorithm, is proposed to solve the model efficiently. The sensitivity information elicited from the optimization model may also provide useful aid to network planning that are discussed. The VAR support cost allocation issue is addressed next. The Shapley value criterion of cooperative gaming is proposed to allocate VAR support costs among the loads contributing to voltage instability. The VAR planning model is implemented for the AEP 14-bus test system. The implications of the sensitivity information are discussed using the test system results. The result of the optimization approach is compared with two existing methods viz., Eigen Value (Modal) and Singular Value Decomposition (SVD) methods. Further, we discuss how the outcome of the Modal analysis could be integrated in the optimization model to form a hybrid approach. A numerical example of calculation of Shapley value is provided and, we also compare it with the conventional method of proportional allocation to gain better insight about this criterion. (C) 2002 Elsevier Science Ltd. All rights reserved.

关键词： VAR planning voltage stability non-linear mixed-integer programming cost allocation

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Voltage stability constrained VAR planning - A case study for New Zealand

Voltage stability constrained VAR planning - A case study fo...

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Large Engineering Systems Conference on Power Engineering

作者： Chakrabarti, BB Chattopadhyay, D Kumble, C Transpower New Zealand Ltd Network Planning Grp Wellington New Zealand

ISBN: (纸本)0780371070

This paper discusses a VAR planning optimisation model that takes into account voltage stability constraint, and proposes an efficient solution algorithm to solve it. A contingency constrained optimal power flow (OPF) based model incorporating (static) voltage stability constraints is developed to analyse optimal VAR support decisions. Given a set of contingencies, the model performs the contingency ranking, decides optimal location and quantity of VAR support to simultaneously cover all the contingencies. DICOPT++, a state-of-the-art mixed integer non-linear programming (MINLP) algorithm, is proposed to solve the model efficiently. The model is implemented for a 17 bus reduced New Zealand North Island system. The modal analysis is also conducted and the result is discussed.

关键词： contingency constrained VAR planning Static voltage stability non-linear mixed-integer programming modal analysis

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