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Greedy algorithm for Minimizing the Cost of Routing Power on a Digital Microgrid

ENERGIES 2019年第16期12卷 3076页

作者： Jiang, Zhengqi Sahasrabudhe, Vinit Mohamed, Ahmed Grebel, Haim Rojas-Cessa, Roberto New Jersey Inst Technol Dept Elect & Comp Engn Newark NJ 07102 USA CUNY City Coll Dept Elect Engn New York NY 10031 USA

In this paper, we propose the greedy smallest-cost-rate path first (GRASP) algorithm to route power from sources to loads in a digital microgrid (DMG). Routing of power from distributed energy resources (DERs) to loads of a DMG comprises matching loads to DERs and the selection of the smallest-cost-rate path from a load to its supplying DERs. In such a microgrid, one DER may supply power to one or many loads, and one or many DERs may supply the power requested by a load. Because the optimal method is NP-hard, GRASP addresses this high complexity by using heuristics to match sources and loads and to select the smallest-cost-rate paths in the DMG. We compare the cost achieved by GRASP and an optimal method based on integer linear programming on different IEEE test feeders and other test networks. The comparison shows the trade-offs between lowering complexity and achieving optimal-cost paths. The results show that the cost incurred by GRASP approaches that of the optimal solution by small margins. In the adopted networks, GRASP trades its lower complexity for up to 18% higher costs than those achieved by the optimal solution.

关键词： digital microgrid power grid integer linear programming routing energy distributed energy resources dijkstra algorithm integer linear programming

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Real-time evacuation route optimization in the fire scenarios of cruise ships

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SIMULATION MODELLING PRACTICE AND THEORY 2023年 129卷

作者： Liu, Linfan Zhang, Huajun Shi, Jun Geng, Jianning Wuhan Univ Technol Sch Automat Wuhan 430063 Peoples R China CSSC Marine Technol Co Ltd Shanghai 20000 Peoples R China

The optimization of evacuation routes for evacuees in fire scenarios on cruise ships directly affects evacuation efficiency. A time-varying equivalent weight dijkstra algorithm (TVEWDA) is proposed, combining a fire dynamics simulator (FDS) to find optimal evacuation routes in case of a sudden cruise ship fire. First, the FDS software is used to simulate a cruise ship's single and multisource fire scenarios. Second, the dijkstra algorithm using only distance between nodes is improved by considering the effects of CO concentration, visibility, and temperature. The evacuees' speed is taken into consideration within the TVEWDA. The effects of congestion are considered in the evacuees' moving speed. Finally, the TVEWDA and a cruise ship evacuation network model are integrated to develop a real-time evacuation route optimization model. Simulation results show that the evacuation time achieved by the TVEWDA is 22% shorter than that of the dijkstra algorithm using only distance between nodes and 11% shorter than that of an improved social force model in the multi-source fire scenario. This approach is well-suited to guide the evacuation of cruise ship evacuees in the event of single-source or multi-source fires, effectively ensuring the safety of passengers and the preservation of their property.

关键词： Cruise ship dijkstra algorithm Evacuees Fire simulation

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Optimization of Skid Trails and Log Yards on the Amazon Forest

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FORESTS 2019年第3期10卷 252页

作者： Sales, Agust Elera Gonzales, Duberli Geomar Vaz Martins, Thales Guilherme Costa Silva, Gabriela Cristina Spletozer, Aline Goncalves de Almeida Telles, Lucas Arthur Siviero, Marco Antonio Lorenzon, Alexandre Simoes Univ Fed Vicosa Dept Engn Florestal BR-36570900 Vicosa MG Brazil Univ Fed Parana BR-80060000 Curitiba Parana Brazil

Research highlights: We used dijkstra algorithm (DA) to define optimal allocation of yards in order to minimize total skid-trail's distance in the Amazon Forest. DA minimized trails' distances and associated transportation costs, leading to an even smaller value when the current planning was disregarded and suggesting the reduction of deleterious environmental externalities. Background and objectives: We sought to answer if it is possible to optimize distances and intrinsic costs in the management of Amazonian forests using DA. The objective was to minimize skid trails distances by best allocating yards using DA and to compare four scenarios of forest harvest planning in the Brazilian Amazon. Materials and methods: Tree census data from Genesis-Salem Farm, state of Para, Brazil, were used. The yards and roads located by Grupo Arboris (scenario 1) were compared to three alternative scenarios in terms of total skid distance, trails and road densities, and skidding costs for three successive harvests, seeking to minimize total skid-trails' distance. Alternative scenarios were to keep the number of yards within work units (WU) and place them in the edge of existing roads (scenario 2);keep the number of yards within each WU (scenario 3);and place 23 yards, disregarding the current planning (scenario 4). Results: Total skid-trail's distance, number of trees above optimal extraction distance and densities of skid trails and roads were smaller in scenarios 2, 3, and 4, compared to the current yard allocation (scenario 1). Scenario 4, with fewer restrictions, reduced skid-trails' distances by 23%. Harvest costs decreased from scenario 1 to 4 in all three harvest cycles. Conclusions: DA allowed optimized distribution of yards and skid trails and generated efficient results for harvest planning. This reinforces the importance of optimized planning, which establishes satisfactory results in the effort to reduce costs and environmental impact keeping high efficiency.

关键词： forestry planning dijkstra algorithm reduced impact harvesting

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Congestion-Based Earthquake Emergency Evacuation Simulation Model for Underground Structure

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BUILDINGS 2024年第10期14卷 3217-3217页

作者： Yoo, Mintaek Haam, Sunnie Song, Woo Seung Gachon Univ Dept Civil & Environm Engn 1342 Seongnam Daero Seongnam 13120 South Korea Univ Seoul Dept Fire Safety Engn & Disaster Management 163 Seoulsiripdae Ro Seoul 02504 South Korea Urban Life Network Yongun Ro 1-32F Dae Dong Daejeon 34648 South Korea

Herein, the dijkstra algorithm was used to develop a model that considers evacuee congestion and derives an optimal evacuation route in underground structures in the event of an earthquake. The ground conditions and seismic intensities were varied, and the evacuation route was analyzed for four cases. The damage index for each underground structure due to an earthquake was determined considering the ground conditions and structure depth, and the evacuation speed reduction was evaluated as a function of the damage index. A congestion coefficient was applied when the evacuation capacity exceeded the threshold to reflect the evacuation speed reduction due to increased congestion in the same evacuation route. The evacuation route in some sections changed when congestion was considered, and the final evacuation time increased significantly when the congestion coefficient was applied. When the evacuation capacity at each node exceeded the threshold, the 1/3 value was applied as the congestion coefficient to evacuation velocity. When the original evacuation route was used after applying the congestion coefficient, the evacuation time increased by up to 220%. However, the evacuation time can be reduced by applying an alternative route that considers congestion. When an alternative route derived from considering congestion was used, the evacuation time decreased by up to 45% compared to that when the original route was used, and the time required decreased by up to 840 s. Hence, the reduction in evacuation speed due to evacuee congestion must be considered to derive alternative, optimal evacuation routes in the event of a disaster. In addition, evacuation routes should account for the location of evacuees using technologies such as real-time indoor positioning to consider the congestion level of evacuees.

关键词： evacuation simulation model dijkstra algorithm congestion earthquake underground structure

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PMA Partition Method of Water Distribution Network Combined with Gragh Theory

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Procedia Engineering 2017年 186卷 278-285页

作者： Jinliang Gao Fang Yao Yongpeng Xu Guosheng Sun Chengzhi Zheng Shihua Qi Fuyi Cui Harbin Institute of Technology Harbin 150090 P.R. China Guangdong Holding Limited South Reservior Shenzhen Guangdong 518021 P. R. China

A method are proposed combining PMA partition and graph theory with four parts. Using adaptive Affinity Propagation (AP) clustering algorithm with consideration of economic benefit to preliminarily partition water distribution network(WDN) and reasonably determine the partition number. Calculate the shortest path between the clustering centre and water source by dijkstra algorithm and determine water supply inlet of each region. Establish topology discrete optimization model to determine partition boundary, then applying simulated annealing algorithm to solve the model. Vertically and horizontally combining the partitioned areas to ensure the safety of water supply. This method has been applied to the WDN of Y city to control the pressure for the areas with a certain results.

关键词： Water distribution network leakage control PMA partition graph theory AP clustering algorithm dijkstra algorithm simulated annealing algorithm

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Nejkratší cesta mezi dvěma body po povrchu objektu

Nejkratší cesta mezi dvěma body po povrchu objektu

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作者： Mezera, Lukáš Brno University of Technology

Hledání nejkratší cesty patří mezi základní problémy řešené v počítačové geometrii. Optimálním řešením je výpočet pomocí Dijkstrova algoritmu.... 详细信息

Hledání nejkratší cesty patří mezi základní problémy řešené v počítačové geometrii. Optimálním řešením je výpočet pomocí Dijkstrova algoritmu. Existuje ale i celá řada aproximačních algoritmů, které je také možné pro výpočet nejkratší cesty použít.

关键词： Nejkratší cesta trojúhelníkové sítě Dijkstrův algoritmus aproximační algoritmy algoritmus Kanai Suzuki MDSTk VectorEntity OpenSceneGraph Shortest path triangular meshes dijkstra algorithm approximation algorithms Kanai Suzuki algorithm MDSTk

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Optimal path finding algorithms based on SLSD road network model

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Journal of Southeast University(English Edition) 2010年第4期26卷 558-562页

作者：张小国王庆龚福祥东南大学仪器科学与工程学院南京210096

A solution to compute the optimal path based on a single-line-single-directional（SLSD）road network model is *** the traditional road network model,in the SLSD conceptual model,being single-directional and single-line style,a road is no longer a linkage of road nodes but abstracted as a network ***,a road node is abstracted as the linkage of two ordered single-directional *** model can describe turn restrictions,circular roads,and other real scenarios usually described using a *** a computing framework for optimal path finding（OPF）is *** is proved that classical dijkstra and A algorithms can be directly used for OPF computing of any real-world road networks by transferring a super-graph to an SLSD ***,using Singapore road network data,the proposed conceptual model and its corresponding optimal path finding algorithms are validated using a two-step optimal path finding algorithm with a pre-computing strategy based on the SLSD road network.

关键词： optimal path finding road network model conceptual model digital map vehicle navigation system A algorithm dijkstra algorithm

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Automatic PCB Layout Optimization of a DC-DC Converter Through Genetic algorithm Regarding EMC Constraints

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IEEE ACCESS 2021年 9卷 149870-149882页

作者： Belloumi, Wided Breard, Arnaud Hajji, Omssad Vollaire, Christian Slama, Jaleleddine Ben Hadj Ecole Cent Lyon Lab Ampere F-69134 Ecully France Univ Sousse Ecole Natl Ingn Sousse LATIS Lab Adv Technol & Intelligent Syst Sousse 4023 Tunisia

This paper proposes an optimization approach for an automatic buck converter printed circuit board (PCB) design regarding the electromagnetic compatibility (EMC) constraints. The proposed solution is based on the combination of a genetic algorithm (GA) and a dijkstra algorithm to generate the different PCB layout designs. Afterwards, a numerical modeling approach, taking into account all the stray elements, is proposed to obtain an accurate equivalent circuit for the PCB layout using ANSYS Q3D software. Subsequently, the complete behavior of the converter is simulated within SIMPLORER, including the electrical models of the components, the Line Impedance Stabilization Network (LISN) module as well as the PCB layout model. This aims to compute the conducted disturbances such as the common and the differential mode voltages. Then, this approach is implemented in an optimized process to reach the optimal geometry for the printed circuit board layout with the lowest parasitic effect to fit the EMC requirements. Finally, measurements are performed, and the optimization results are presented and investigated, in comparison with reference PCB layout to assess the efficiency of the proposed methodology.

关键词： Layout Optimization Electromagnetic compatibility Capacitors Integrated circuit modeling Impedance Genetic algorithms Electromagnetic compatibility (EMC) PCB layout design dijkstra algorithm genetic algorithm automatic optimization

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Controlled Islanding Based on the Coherency of Generators and Minimum Electrical Distance

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IEEE ACCESS 2021年 9卷 146830-146840页

作者： Aghamohammadi, M. R. Mahdavizadeh, S. Fazel Shahid Beheshti Univ Elect Engn Dept Tehran *** Iran

Inter-area oscillations and cascading failures are the most serious threats to the security of the electric power system. Uncontrolled islanding will occur in the event of an unstable inter-area oscillation or a progressive cascading failure. The establishment of uncontrolled islands with a deficiency in load-generation balance is the main reason for system blackout. Controlled islanding has been proposed as a preventive strategy for reducing the risk of blackout in this regard. A new algorithm for applying the controlled islanding strategy is proposed in this paper, based on load coherency and nearest electrical distances between coherent groups of generators. Coherent generators as the main core for controlled islands are identified in this method, which is based on the correlation coefficients between generators and the DBSCAN clustering algorithm. The sub-networks are then created by applying mixed-integer linear programming to each coherent group. Once this is accomplished, non-linear programming is used to construct the stable sub-networks associated with islands that meet the requirements of load-generation balance, voltage limitations, and transmission limits. The proposed scheme is implemented on the small-scale IEEE 39-bus system and a large-scale realistic power system which is the Iran power grid. The results demonstrate that the proposed method is capable of being implemented in a real power system.

关键词： Intentional islanding generator coherency electrical distances DBSCAN algorithm dijkstra algorithm non-linear programming

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An exact reduction technique for the k-Colour Shortest Path Problem

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COMPUTERS & OPERATIONS RESEARCH 2023年 149卷

作者： Cerrone, Carmine Russo, Davide Donato Univ Genoa Dept Econ I-16126 Genoa Italy Univ Molise Dept Biosci & Terr I-86090 Pesche Italy

The k-Colour Shortest Path Problem is a variant of the classic Shortest Path Problem. This problem consists of finding a shortest path on a weighted edge-coloured graph, where the maximum number of different colours used in a feasible solution is fixed to be k. The k-CSPP has several real-world applications, particularly in network reliability. It addresses the problem of reducing the connection cost while improving the reliability of the network. In this work, we propose a heuristic approach, namely Colour-Constrained dijkstra algorithm (CCDA), which is able to produce effective solutions. We propose a graph reduction technique, namely the Graph Reduction algorithm (GRA), which removes more than 90% of the nodes and edges from the input graph. Finally, using a Mixed-Integer Linear Programming (MILP) model, we present an exact approach, namely Reduced Integer Linear Programming algorithm (RILP), that takes advantage of the heuristic CCDA and the GRA. Several tests were performed to verify the effectiveness of the proposed approaches. The computational results indicate that the produced approaches perform well, in terms of both the solution's quality and computation times.

关键词： Graph reduction dijkstra algorithm Shortest path Labelled graph

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