In this paper, a reliable soft computing framework is presented for the approximate solution of initial value problem (IVP) of first Painlev, equation using three unsupervised neural network models optimized with sequ...
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In this paper, a reliable soft computing framework is presented for the approximate solution of initial value problem (IVP) of first Painlev, equation using three unsupervised neural network models optimized with sequential quadratic programming (SQP). These mathematical models are constructed in the form of feed-forward architecture including log-sigmoid, radial base and tan-sigmoid activation functions in the hidden layers. The optimization of designed parameters for each model is performed with SQP, an efficient constraint optimization problem-solving algorithm. The designed methodology is tested on the IVP, and comparative study is carried out with standard solution based on numerical and analytical solvers. The accuracy, convergence and effectiveness of the schemes are validated on the given benchmark problem by large number of simulations and their comprehensive analysis.
A study is conducted to demonstrate constraint handling and multi-objective methods for the evolution of interplanetary trajectories. The study is based on the methods developed during GTOC6 and few advanced evolution...
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A study is conducted to demonstrate constraint handling and multi-objective methods for the evolution of interplanetary trajectories. The study is based on the methods developed during GTOC6 and few advanced evolutionary techniques able to evolve complex Jupiter capture options are proposed. The evolutionary process is set up to be able to deal with constraints, along with multiple objectives and show the use of advanced evolutionary techniques to effectively search the solution space in both cases. The investigations show how these techniques allow the evolution of solutions of use to trajectory designers for the complex trajectory case considered in this study where other approaches fail to find acceptable solutions in a reasonable time.
A study is conducted to demonstrate the wind-fixed frame (WFF) approach, effectively using it as a pre-transformation to simplify path planning while explicitly accounting for estimated wind field motion. The main con...
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A study is conducted to demonstrate the wind-fixed frame (WFF) approach, effectively using it as a pre-transformation to simplify path planning while explicitly accounting for estimated wind field motion. The main contribution of this study is a novel guidance algorithm enabling the system to generate trajectories in any wind condition for any phase of flight. The algorithm follows from optimal control principles and allows the specification of terminal boundary conditions while minimizing steering control effort. A nonholonomic fixed-time optimal path planning method arises naturally, with parameterized elliptic functions acting as the key trajectory descriptor by formulating parafoil guidance in this manner.
Abstract-This article describes a multi-objective optimization method to solve the optimal distributed generation sizing and placement. The optimization problem considers two objectives: minimizing the total real powe...
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Abstract-This article describes a multi-objective optimization method to solve the optimal distributed generation sizing and placement. The optimization problem considers two objectives: minimizing the total real power losses of the network and minimizing the overall distributed generation installation cost. The objectives are combined into a scalar objective optimization problem by using weighted sum method. Both objective functions and equality and inequality constraints are formulated as a non-linear program and solved by a sequential quadratic programming deterministic technique. The multi-objective optimization method gives several answers instead of a single (unique) one. These answers are optimal, and the designer (decision maker) can select the proper solution according to subjective preferences. These optimum results are known as the Pareto front. A fuzzy decision-making procedure for order preference is used for finding the best compromise solution from the set of Pareto solutions. The proposed method is tested using a 15-bus radial distribution system to show its applicability. A comparative study is performed to evaluate two cases-a single distributed generation unit installation and a multiple distributed generation installation-ending by a comparative study of the two cases.
This paper investigates a Finite-Control-Set Model Predictive Control (FCS-MPC) for the precise control of (un)balanced load currents in Modular Multilevel Converter (MMC). The control objectives are circulating curre...
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ISBN:
(纸本)9781467395519
This paper investigates a Finite-Control-Set Model Predictive Control (FCS-MPC) for the precise control of (un)balanced load currents in Modular Multilevel Converter (MMC). The control objectives are circulating currents minimization inside the converter arms, achieve a capacitors voltage balance and load current control. To achieve the converter constrained optimization and facilitate the implementation on embedded systems, an integrated perturbation analysis and sequential quadratic programming (IPA-SQP) solver is also utilized. As a case study the proposed approach is applied to a grid-connected five-level MMC. The introduced FCS-MPC formulation reduces sensitivity of the converter output voltage to disturbances in grid side and measurement noise with reducing the computational burden. Simulation results reveal the effectiveness of the developed control scheme in cases when operational objectives, e.g., load current reference tracking and disturbance rejection are considered under system model uncertainties.
This paper investigates the MIMO radar orthogonal waveform design problem. The result shows the ambiguity function (AF) property of the sum of transmitted signals is as important as the autocorrelation and crosscorrel...
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This paper investigates the MIMO radar orthogonal waveform design problem. The result shows the ambiguity function (AF) property of the sum of transmitted signals is as important as the autocorrelation and crosscorrelation properties of transmitted signals. An orthogonal zero correlation zone (ZCZ) phase codes design method was proposed to simultaneously satisfy these property requirements. The idea is to simultaneously constrain the peak sidelobe of the AF Of sum signal in ZCZ, and the peak sidelobe of aperiodic autocorrelation function (ACF) and peak of the aperiodic crosscorrelation function (CF) within ZCZ. We used the sequential quadratic programming (SOP) method to solve the nonlinear optimization problem with multi-variables and multi-constraints. Some of the designed results are presented, and their properties are improved significantly. The designed orthogonal ZCZ codes promise to be practically applicable.
A new targeting technique using the homotopy method has been developed to obtain the non-Keplerian solution based on the Keplerian solution of a Lambert transfer orbit. To achieve this goal, a group of intermediate ta...
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A new targeting technique using the homotopy method has been developed to obtain the non-Keplerian solution based on the Keplerian solution of a Lambert transfer orbit. To achieve this goal, a group of intermediate target points is used to approach the desired target point iteratively. This targeting technique can successfully obtain the non-Keplerian solution even for a long-duration orbit transfer problem. A universal optimization model is then built based on the homotopy targeting technique for the perturbed impulsive rendezvous problem.
Gravitational search algorithm (GSA) has shown an effective performance for solving real-world optimization problems. However, it suffers from premature convergence because of quick losing of diversity. To enhance its...
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Gravitational search algorithm (GSA) has shown an effective performance for solving real-world optimization problems. However, it suffers from premature convergence because of quick losing of diversity. To enhance its performance, this paper proposes a novel GSA algorithm, called GSA-PWL (piecewise linear)-SQP (sequential quadratic programming), which employs a diversity enhancing mechanism and an accelerated local search strategy to achieve a trade-off between exploration and exploitation abilities. A comprehensive experimental study is conducted on a set of benchmark functions. Comparison results show that GSA-PWL-SQP obtains a promising performance on the majority of the test problems. Furthermore, the GSA-PWL-SQP is applied to data fitting with B-splines to solve very difficult continuous multimodal and multivariate nonlinear optimization problem. The method of data fitting based on GSA-PWL-SQP yields very accurate results even for curves with singularities and/or cusps and is very efficient in terms of data points error, AIC and BIC criteria.
In the present study, novel soft computing techniques are developed for numerical treatment of nonlinear thin film flow (TFF) problem of third grade fluids using artificial neural networks (ANNs), particle swarm optim...
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In the present study, novel soft computing techniques are developed for numerical treatment of nonlinear thin film flow (TFF) problem of third grade fluids using artificial neural networks (ANNs), particle swarm optimization (PSO), sequential quadratic programming (SQP), and their hybrid combinations. The strength of universal function approximation capabilities of ANNs is exploited in formulation of mathematical model of the problem based on an unsupervised error. The training of the design parameter of the networks is performed with PSO, SQP, and hybrid approach PSO-SQP. The proposed schemes are evaluated on four variants of the two cases of TFF problems by taking different values of material parameter and Stokes number. The reliability and effectiveness of the proposed approaches are validated through the results of statistical analyses based on sufficient large number of independent runs. (C) 2014 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
A novel design of timed Vivaldi antenna arrays for steerable energy patterns is presented in this work. Three geometries are studied and designed in order to obtain an optimum energy pattern with low side lobe level (...
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A novel design of timed Vivaldi antenna arrays for steerable energy patterns is presented in this work. Three geometries are studied and designed in order to obtain an optimum energy pattern with low side lobe level (SLL) during beam steering: equally antenna array, unequally antenna array, and concentric ring array. The antenna elements are fed with the fifth derivative Gaussian pulse. The design process is carried out by the well-known sequential quadratic programming. Three design examples with 16 antenna elements are studied by considering different distribution of antenna positions. The mutual coupling phenomenon is considered by full wave simulations of Vivaldi antenna elements in the design examples. The results show a good performance of the steerable energy pattern with low SLL with ultra wideband operation.
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