The main objective of this study is to identify the piezoelectric actuator (PA) with hysteresis, which is described by Bouc-Wen model. The identification method based on real-coded genetic algorithm (RGA) has the adva...
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The main objective of this study is to identify the piezoelectric actuator (PA) with hysteresis, which is described by Bouc-Wen model. The identification method based on real-coded genetic algorithm (RGA) has the advantages not only to, identify the parameters of the hysteresis model but also the mass, stiffness, damping coefficient and piezoelectric coefficient of the PA simultaneously. Furthermore, the selection of fitness functions in the RGA is the key point to influence the final identified results. In this paper, three types of fitness functions are designed to identify the hysteretic PA and their differences are discussed. The numerical simulations and experimental results demonstrate that the identification method based on the RGA with suitable fitness functions is feasible. (c) 2006 Elsevier B.V. All rights reserved.
The present study aims to implement a new selection method and a novel crossover operation in a real-coded genetic algorithm. The proposed selection method facilitates the establishment of a successively evolved popul...
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The present study aims to implement a new selection method and a novel crossover operation in a real-coded genetic algorithm. The proposed selection method facilitates the establishment of a successively evolved population by combining several subpopulations: an elitist subpopulation, an off-spring subpopulation and a mutated subpopulation. A probabilistic crossover is performed based on the measure of probabilistic distance between the individuals. The concept of 'allowance' is suggested to describe the level of variance in the crossover operation. A number of nonlinear/non-convex functions and engineering optimization problems are explored to verify the capacities of the proposed strategies. The results are compared with those obtained from other genetic and nature-inspired algorithms.
This paper aims to obtain the optimal composite box-beam design for a helicopter rotor blade. The cross-sectional dimensions and the ply angles of the box beam are considered as design variables. The objective is to o...
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This paper aims to obtain the optimal composite box-beam design for a helicopter rotor blade. The cross-sectional dimensions and the ply angles of the box beam are considered as design variables. The objective is to optimize the box beam to attain a target vector of stiffness values and maximum elastic coupling. The target vector is the optimal stiffness values of helicopter rotor blade obtained from a previous aeroelastic optimization study. The elastic couplings introduced by the box beam have beneficial effects on the aeroelastic stability of helicopter. The optimization problem is addressed by decomposing the optimization into two levels, a global level and a local level. The box-beam cross-sectional dimensions are optimized at the global level. The local-level optimization is a subproblem which finds optimal ply angles for each cross-sectional dimension considered in the global level. real-coded genetic algorithm (RCGA) is used as the optimization tool in both the levels of optimization. Hybrid operators are developed for the RCGA, thereby enhancing the efficiency of the algorithm. Min-max method is used to scalarize the multiobjective functions used in this study. Optimal geometry and ply angles are obtained for composite box-beam designs with ply angle discretization of 10, 15, and 45 degrees.
We develop a real-coded constrained geneticalgorithm (GA) and assess its performance for the case of selected classical optimisation problems. The proposed GA uses a roulette selection method, BLX-alpha cross-over op...
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We develop a real-coded constrained geneticalgorithm (GA) and assess its performance for the case of selected classical optimisation problems. The proposed GA uses a roulette selection method, BLX-alpha cross-over operation, non-uniform mutation along with single elitist selection at every generation. The GA is then applied, in conjunction with the finite element (FE) method, to optimise the damping response of a laminate comprising unidirectional composite laminae and viscoelastic damping layers. Modal loss factors are maximised against the constraints of given structural stiffness and mass. (C) 2018 Elsevier Ltd. All rights reserved.
The hybrid geneticalgorithm is utilized to facilitate model parameter *** tri-dimensional compression tests of soil are performed to supply experimental data for identifying nonlinear constitutive model of *** order ...
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The hybrid geneticalgorithm is utilized to facilitate model parameter *** tri-dimensional compression tests of soil are performed to supply experimental data for identifying nonlinear constitutive model of *** order to save computing time during parameter inversion,a new procedure to compute the calculated strains is presented by multi-linear simplification approach instead of finite element method(FEM).The real-coded hybrid geneticalgorithm is developed by combining normal geneticalgorithm with gradient-based optimization *** numerical and experimental results for conditioned soil are *** forecast strains based on identified nonlinear constitutive model of soil agree well with observed *** effectiveness and accuracy of proposed parameter estimation approach are validated.
In this paper, we develop a parallel-structured real-coded genetic algorithm (RCGA), named the RGA-RDD, for numerical optimization. Technically, the proposed RGA-RDD integrates three specially designed evolutionary op...
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In this paper, we develop a parallel-structured real-coded genetic algorithm (RCGA), named the RGA-RDD, for numerical optimization. Technically, the proposed RGA-RDD integrates three specially designed evolutionary operators - the Ranking Selection (RS), Direction-Based Crossover (DBX), and the Dynamic Random Mutation (DRM) - as a whole to mimic a specific evolutionary process. Unlike the conventional RCGAs that perform evolutionary operators in a series framework, the RGA-RDD embeds a coordinator in the inner parallel loop to organize the operations of the DBX and DRM so that a higher possibility of locating the global optimum is ensured. Besides, based on the results of a systematic parametric analysis, we provide a parameter selection guideline for the settings of the proposed RGA-RDD. Furthermore, a data-driven optimization scheme, which incorporates the uniform design for design of experiments and a shape-tunable neural network for auxiliary decision support, is applied to search for an optimal set of the algorithm parameters. The effectiveness and applicability of the proposed RGA-RDD are demonstrated through a variety of benchmarked optimization problems, followed by comprehensive comparisons with some existing state-of-the-art evolutionary algorithms. Extensive simulation results reveal that the performance of the proposed RGA-RDD is superior to comparative methods in locating the global optimum for real-parameter optimization problems, especially for unsolved multimodal and high-dimensional hybrid functions. (C) 2015 Elsevier Inc. All rights reserved.
Hopf bifurcation in power systems leads to oscillatory instability, and it is desirable to operate the system with sufficiently large loading margin to Hopf bifurcation. A new technique to determine the shortest dista...
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Hopf bifurcation in power systems leads to oscillatory instability, and it is desirable to operate the system with sufficiently large loading margin to Hopf bifurcation. A new technique to determine the shortest distance to Hopf bifurcation is developed. The problem of determining the closest Hopf bifurcation point is formulated as an optimisation problem and solved using real-coded genetic algorithm. The advantage of this method is that it is capable of handling various operational constraints and can determine the closest Hopf bifurcation point accurately even if the hypersurface is not smooth. The proposed approach has been applied on two-area and IEEE 14-bus test systems. The details of implementation and simulation results are presented. The effect of load modelling on closest Hopf bifurcation point is also investigated for various loading patterns.
This paper presents the results of employing a real-coded genetic algorithm (GA) to the problem of determining the optimal unit pulse response function (UPRF) using the historical data from watersheds. The existing li...
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This paper presents the results of employing a real-coded genetic algorithm (GA) to the problem of determining the optimal unit pulse response function (UPRF) using the historical data from watersheds. The existing linear programming (LP) formulation has been modified, and a new problem formulation is proposed. The proposed problem formulation consists of fewer decision variables, only one constraint, and a non-linear objective function. The proposed problem formulation can be used to determine an optimal UPRF of a watershed from a single storm or a composite UPRF from multiple storms. The proposed problem formulation coupled with the solution technique of real-coded GA is tested using the effective rainfall and runoff data derived from two different watersheds and the results are compared with those reported earlier by others using LP methods. The model performance is evaluated using a wide range of standard statistical measures. The results obtained in this study indicate that the real-coded GA can be a suitable alternative to the problem of determining an optimal UPRF from a watershed. The proposed problem formulation when solved using real-coded GA resulted in smoother optimal UPRF without the need of additional constraints. The proposed problem formulation can be particularly useful in determining the optimal composite UPRF from multiple storms in large watersheds having large time bases due to its limited number of decision variables and constraints. (c) 2004 Elsevier B.V. All rights reserved.
An efficient optimisation procedure based on real-coded genetic algorithm (RCGA) is proposed for the solution of economic load dispatch (ELD) problem with continuous and nonsmooth/nonconvex cost function and with vari...
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An efficient optimisation procedure based on real-coded genetic algorithm (RCGA) is proposed for the solution of economic load dispatch (ELD) problem with continuous and nonsmooth/nonconvex cost function and with various constraints being considered. The effectiveness of the proposed algorithm has been demonstrated on different systems considering the transmission losses and valve point loading effect in thermal units. The proposed algorithm is equipped with an effective constraint handling technique, which eliminates the need for penalty parameters. For the purpose of comparison, the same problem has also been solved using binary-codedgeneticalgorithm (BCGA) and three other popular RCGAs. In the proposed RCGA, simulated binary crossover and polynomial mutation are used against the single point crossover and bit-flipping mutation in BCGA. It has been observed from the test results that the proposed RCGA is more efficient in terms of thermal cost minimisation and execution time for ELD problem with continuous search space than BCGA and some other popular RCGAs. (C) 2008 Elsevier B.V. All rights reserved.
The use of Recurrent Neural Networks is not as extensive as Feedforward Neural Networks. Training algorithms for Recurrent Neural Networks, based on the error gradient, are very unstable in their search for a minimum ...
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The use of Recurrent Neural Networks is not as extensive as Feedforward Neural Networks. Training algorithms for Recurrent Neural Networks, based on the error gradient, are very unstable in their search for a minimum and require much computational time when the number of neurons is high. The problems surrounding the application of these methods have driven us to develop new training tools. In this paper, we present a real-coded genetic algorithm that uses the appropriate operators for this encoding type to train Recurrent Neural Networks. We describe the algorithm and we also experimentally compare our geneticalgorithm with the real-Time Recurrent Learning algorithm to perform the fuzzy grammatical inference. (C) 2001 Elsevier Science Ltd. All rights reserved.
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