Like wireless sensor networks, lifetime of sensors is the main constraint for performance of underwater acoustic sensor networks (UASNs). Most previous works on UASNs did not consider dynamics of networks, i.e., as ti...
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Like wireless sensor networks, lifetime of sensors is the main constraint for performance of underwater acoustic sensor networks (UASNs). Most previous works on UASNs did not consider dynamics of networks, i.e., as time goes by, in practice, part of sensors may be malfunctioned, deplete their battery power, or get lost due to violent underwater environment changes. Therefore, this paper considers a UASN in ocean and proposes a sleep scheduling scheme in which sensor nodes and autonomous underwater vehicles in this network can dynamically choose to sleep or work to adapt to the environmental change. The concerned problem is to dynamically determine a sufficient number of active nodes in the UASN at different times, such that the targets required to be detected are covered. A special static scenario of the problem has been shown to be NP-complete. Hence, this paper proposes an improved multi-population harmony search algorithm to solve this dynamic problem. By simulation, the proposed algorithm shows high performance in terms of extending network lifetime, robustness, and computing time.
This paper proposes a Pareto-based grouping discrete harmony search algorithm (PGDHS) to solve the multi-objective flexible job shop scheduling problem (FJSP). Two objectives, namely the maximum completion time (makes...
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This paper proposes a Pareto-based grouping discrete harmony search algorithm (PGDHS) to solve the multi-objective flexible job shop scheduling problem (FJSP). Two objectives, namely the maximum completion time (makespan) and the mean of earliness and tardiness, are considered simultaneously. Firstly, two novel heuristics and several existing heuristics are employed to initialize the harmony memory. Secondly, multiple harmony generation strategies are proposed to improve the performance of harmony search algorithm. The operation sequence in a new harmony is produced based on the encoding method and the characteristics of FJSP. Thirdly, two local search methods based on critical path and due date are embedded to enhance the exploitation capability. Finally, extensive computational experiments are carried out using well-known benchmark instances. Three widely used performance measures, number of non-dominated solutions, diversification metric and quality metric, are employed to test the performance of PGDHS algorithm. Computational results and comparisons show the efficiency and effectiveness of the proposed PGDHS algorithm for solving multi-objective flexible job-shop scheduling problem. (C) 2014 Published by Elsevier Inc.
In the optimum coordination of Directional Overcurrent Relays (DOCRs), the appropriate relay settings, namely, Plug Setting (PS) and Time Multiplier Setting (TMS), are selected to minimize the operating time of relays...
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In the optimum coordination of Directional Overcurrent Relays (DOCRs), the appropriate relay settings, namely, Plug Setting (PS) and Time Multiplier Setting (TMS), are selected to minimize the operating time of relays subject to various coordination and boundary constraints. In the large interconnected power systems, the key issue with DOCRs protection is to achieve correct relay coordination with satisfying all coordination constraints. In this paper, the parameters of harmony search algorithm (HSA) are tuned to effectively solve the relay coordination problem on five different test cases. Also, the relay coordination problem is formulated as Linear Programming Problem (LPP), Non-linear Programming Problem (NLPP) and Mixed-Integer non-linear programming Problem (MINLPP). In addition, the superiority of proposed method is demonstrated by comparing the obtained results with those obtained by the Genetic algorithm (GA), hybrid GA-Nonlinear Programming (GA-NLP), Firefly algorithm (FFA), and Cuckoo searchalgorithm (CSA). (C) 2017 Elsevier Inc. All rights reserved.
Dynamic optimization problems present great challenges to the research community because their parameters are either revealed or changed during the course of an ongoing optimization process. These problems are more ch...
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Dynamic optimization problems present great challenges to the research community because their parameters are either revealed or changed during the course of an ongoing optimization process. These problems are more challenging than static problems in real-world applications because the latter are usually dynamic, with the environment constantly subjected to change or the size of a problem increasing sporadically. In solving dynamic optimization problems in the real world, proposed solutions should be able to monitor the movement of the optimal point and the changes in the landscape solutions. In this paper, a multi-population harmony search algorithm with external archive for dynamic optimization problems is proposed. harmony search algorithm is a population-based meta-heuristic optimization technique that is similar to a musical process when a musician is attempting to find a state of harmony. To tackle the problem of dynamism, the population of solutions is divided into several sub-populations such that each sub-population takes charge exploring or exploiting the search space. To enhance the algorithm performance further, an external archive is used to save the best solutions for later use. These solutions will then be used to replace redundant solutions in the harmony memory. The proposed algorithm is tested on the Moving Peak Benchmark. Empirical results show that the proposed algorithm produces better results than several of the current state-of-the-art algorithms. (C) 2014 Elsevier Inc. All rights reserved.
Large-scale system reliability problem is a nonconvex integer nonlinear programming problem, traditional mathematical programming methods have computation limits and can not optimize an effective solution in a reasona...
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Large-scale system reliability problem is a nonconvex integer nonlinear programming problem, traditional mathematical programming methods have computation limits and can not optimize an effective solution in a reasonable time. This paper employed an amended harmony search algorithm(AHS) to solve large-scale system reliability problems. In AHS, perturbation strategy, key parameter adjustment and global dimension selection strategy are designed to balance the capability of exploitation and exploration. A comprehensive comparison is carried out to assess the search efficiency and convergence performance of AHS. Function test and large-scale system reliability case results show that AHS is superior to many previously reported well-known and excellent algorithms.
The efficiency of automatic guided vehicle (AGV) scheduling is important to improve the productivity of manufacturing enterprises. In this paper, the production materials and cutting tools consumables are transferred ...
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The efficiency of automatic guided vehicle (AGV) scheduling is important to improve the productivity of manufacturing enterprises. In this paper, the production materials and cutting tools consumables are transferred by multiple AGVs and a multi-objective mathematical model of AGV scheduling is established, which contains three objectives, i.e., the total travel distance of AGVs, the standard deviation of AGVs workload and the standard deviation of the difference between the latest delivery time and the predicted time of tasks. Then, an improved harmonysearch (HS) algorithm is proposed by adopting dynamic changing harmony memory considering rate (HMCR) parameters and implementing neighborhood search strategy for the best harmony in harmony memory (HM). Meanwhile, the harmony is divided into several segments according to the capacitated multiple-load AGVs. Each segment corresponds to the tasks execution scope of AGVs that return to the warehouse in turn. And the elements sequence of each segment represents the order of these tasks performed by AGV. At the same time, calculating the fitness value in each segment of harmony, and finally adding them up as the total fitness value of the whole harmony. A larger-scale instance from the real-life manufacturing enterprise is used to evaluate the performance of the proposed HS algorithm. The computational results show that the proposed HS algorithm outperforms the current solution.
harmonysearch (HS) is a recent EA inspired by musical improvisation process to seek a pleasing harmony. Mutation is a vital component used in Evolutionary algorithms (EA) where a value in the population is randomly s...
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harmonysearch (HS) is a recent EA inspired by musical improvisation process to seek a pleasing harmony. Mutation is a vital component used in Evolutionary algorithms (EA) where a value in the population is randomly selected to be altered to improve the evolution process. The original HS algorithm applies an operation similar to mutation during the random consideration operator. During random selection operator a value within the range of the decision variable is selected randomly to explore different areas in the search space. This paper aims at experimentally evaluating the performance of HS algorithm after replacing the random consideration operator in the original HS with five different mutation methods. The different variations of HS are experimented on standard benchmark functions in terms of final obtained solution and convergence speed. The results show that using polynomial mutation improves the performance of the HS algorithm for most of the used functions. (C) 2013 Elsevier Inc. All rights reserved.
An accurate and effective technology for fault diagnosis of a high-voltage transmission line plays an important role in supporting rapid system restoration. The fault diagnosis of a high-voltage transmission line invo...
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An accurate and effective technology for fault diagnosis of a high-voltage transmission line plays an important role in supporting rapid system restoration. The fault diagnosis of a high-voltage transmission line involves three major tasks, namely fault-type identification, fault location and fault time estimation. The diagnosis problem is formulated as an optimisation problem in this work: the variables involved in the fault diagnosis problem, such as the fault location, and the unknown variables such as ground resistance, are taken into account as optimisation variables;the sum of the discrepancy of the approximation components of the actual and expected waveforms is taken as the optimisation objective. Then, according to the characteristics of the formulated optimisation problem, the harmonysearch, an effective heuristic optimisation algorithm developed in recent years, is employed to solve this problem. Test results for a sample power system have shown that the developed fault diagnosis model and method are correct and efficient.
In this paper, we use a recently proposed algorithm-novel global harmonysearch (NGHS) algorithm to solve unconstrained problems. The NGHS algorithm includes two important operations: position updating and genetic mut...
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In this paper, we use a recently proposed algorithm-novel global harmonysearch (NGHS) algorithm to solve unconstrained problems. The NGHS algorithm includes two important operations: position updating and genetic mutation with a low probability. The former can enhance the convergence of the NGHS, and the latter can effectively prevent the NGHS from being trapped into the local optimum. Based on a large number of experiments, the NGHS has demonstrated stronger convergence and stability than original harmonysearch (HS) algorithm and its two improved algorithms (IHS and SGHS). (C) 2010 Elsevier B.V. All rights reserved.
For the scheduling problem of Semiconductor wafer fabrication(SWF), a new Dispatching rule based on the load balance(DRLB) is proposed. Further, a new harmonysearch(HS) algorithm based receipt priority interval(HS rp...
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For the scheduling problem of Semiconductor wafer fabrication(SWF), a new Dispatching rule based on the load balance(DRLB) is proposed. Further, a new harmonysearch(HS) algorithm based receipt priority interval(HS rpi) is presented to minimize the mean cycle time. A kind of chaotic sequence is used as the harmony vector. Then, a conversion method is designed to convert the real number harmony vector to the mixed vector representing the priorities of all receipts and the algorithm parameters. In order to increase the algorithm robustness and decrease the scale of the scheduling problem, based on receipt priority interval and DRLB, we give a special conversion method used to convert the above mixed vector to the solution of the scheduling problem of SWF. Computational simulations based on the practical instances validate the proposed algorithm.
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