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60th Annual Conference of the Society-of-Instrument-and-Control-Engineers-of-Japan (SICE)

作者： Fujikaway, Takahiro Yonemoto, Koichi Tokyo Univ Sci Dept Mech Engn Noda Chiba Japan

ISBN: (纸本)9784907764739

This paper presents a numerical method for finding multiple locally optimal solutions to multi-modal trajectory optimization problems. Starting from an already-found local solution, a saddle-point search algorithm finds a surrounding saddle point of the constrained optimization problem, from which a new local solution is obtained by applying a gradient-based optimizer. Although the developed method is not rigorously guaranteed to produce the global solution, it is applicable to large-scale generic trajectory optimization problems, which makes it a practically beneficial technique. In addition, saddle-point trajectories sometimes yield insightful information on the relationships and reasons of the obtained local optimal trajectories. Validity and utility of the proposed methodology are demonstrated by solving simple but illustrative example problems.

关键词： Trajectory optimization Optimal control Global optimization Saddle point gradient-based method

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A New Assisted History Matching Approach for Complex Reservoirs

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ENERGY SOURCES PART A-RECOVERY UTILIZATION AND ENVIRONMENTAL EFFECTS 2015年第18期37卷 1954-1961页

作者： Dang, T. Q. C. Chen, Z. Nguyen, T. B. N. Bae, W. Phung, T. H. Univ Calgary Dept Chem & Petr Engn Calgary AB T2N 1N4 Canada Sejong Univ Dept Energy & Mineral Resources Engn Seoul 143747 South Korea Vietsovpetro JV Res & Engn Inst Vung Tau City Vietnam

This article describes the integration of mathematical models (Simplex and steepest descent algorithm) with global modification (through deeply geological studies) to increase the efficiency of history matching. This method can take full advantage of the gradient-based method (fast rate of convergence) and guarantee of finding a global minimum for inverse problems. The above method is applied to the Lower Miocene reservoir at White Tiger field, a highly heterogeneous reservoir, which has been producing under a naturally edge-water mechanism. A model that covers the upper formation of White Tiger field with 27 production wells and 8 injection wells is conditioned to 23 years of production history. The new assisted history matching approach provides an excellent match between simulation results and production data.

关键词： assisted history matching global optimization gradient-based method simplex algorithm steepest descent algorithm

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Optimization of structures subjected to earthquake excitation using two-point adaptive approximation with trust region strategy

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STRUCTURES 2024年 65卷

作者： Feng, Yue Hainan Univ Dept Civil Engn & Architecture Hainan 570228 Peoples R China

This study presents a gradient-based method, TPAA-TR, for optimizing structures under earthquake excitation. The method develops an efficient algorithm that can converge quickly to the optimal solution under time history loading. It uses two-point exponential approximation with consistent intermediate variables to construct explicit linear sub-problems, and applies filter method and trust region strategy to solve them. Merit functions and filters are used to balance the trade-off between reducing objectives and satisfying constraints, and promote convergence. The method performs nonlinear response history analysis for seismic analysis to account for the nonlinear behavior of structures. The effectiveness of the proposed method is demonstrated by three numerical examples: a three-story shear frame, a six-story frame installed with nonlinear devices and a nine-story three-dimensional (3D) reinforced concrete (RC) nonlinear building. The results show that the proposed method can achieve optimal solutions with less computational time and fewer function evaluations than existing methods.

关键词： Optimization gradient-based method Earthquake Approximation Trust region

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Time-delayed decentralized H2/LQG controller for cable-stayed bridge under seismic loading

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STRUCTURAL CONTROL & HEALTH MONITORING 2013年第3期20卷 354-372页

作者： Fallah, Arash Yeganeh Taghikhany, Touraj Amirkabir Univ Technol Dept Civil & Environm Engn Tehran Iran

Consistency of real-time data transmission is an important factor in active and semi-active control of structures. Recent advances in wireless sensors and their reliable data communication have attracted many attentions in structural control engineering. Wireless sensors have been also preferred to wire-base types because of problems associated with installing extensive length of coaxial wires. In addition, embedded computing technologies in wireless sensors as local controller reduce size of transferring data and provide stable transmission. However, there are some issues in implementation of wireless connection like communication range and latency. This study presents the feasibility of developing a decentralized controller by using H2/LQG as robust-optimum algorithm in cable-stayed bridge. Because of large scale of structure, the order of model is reduced by using two different reduction methods in finite time and frequency. The controller is developed in centralized and decentralized solutions. The decentralized controller through developing a gradient-based method is designed to efficiently solve system of closed-loop H2 optimization problem. The structural responses in centralized and decentralized solutions are compared with each other under three different earthquake records considering time delay in data transmission. Results indicate that for large-scale bridges with time-delayed data communication issue, H2/LQG controller in decentralized solution gives maximum reduction of response indices in comparison with other strategies. Copyright (C) 2011 John Wiley & Sons, Ltd.

关键词： H2 LQG decentralized time delay model order reduction gradient-based method

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An evolutionary algorithm for optimal damper placement to minimize interstorey-drift transfer function in shear building

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EARTHQUAKES AND STRUCTURES 2010年第3期1卷 289-306页

作者： Fujita, Kohei Yamamoto, Kaoru Takewaki, Izuru Kyoto Univ Dept Urban & Environm Engn Nishikyo Ku Kyoto 6158540 Japan

A gradient-based evolutionary optimization methodology is presented for finding the optimal design of viscous dampers to minimize an objective function defined for a linear multi-storey structure. The maximum value along height of the transfer function amplitudes for the interstorey drifts is taken as the objective function. Since the ground motion includes various uncertainties, the optimal damper placement may be different depending on the ground motion used for design. Furthermore, the transfer function treated as the objective function depends on the properties of structural parameters and added dampers. This implies that a more robust damper design is desired. A reliable and robust damping design system against any unpredictable ground motions can be provided by minimizing the maximum transfer function. Such design system is proposed in this paper.

关键词： optimal damper placement transfer function evolutionary optimization gradient-based method earthquake response

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Finding tradeoffs by using multiobjective optimization algorithms

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TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES 2004年第155期47卷 51-58页

作者： Obayashi, S Sasaki, D Oyama, A Tohoku Univ Inst Fluid Sci Sendai Miyagi Japan Tohoku Univ Dept Syst Informat Sci Sendai Miyagi Japan NASA Glenn Res Ctr Cleveland OH USA

The objective of the present study is to demonstrate performances of Evolutionary Algorithms (EAs) and conventional gradient-based methods for finding Pareto fronts. The multiobjective optimization algorithms are applied to analytical test problems as well as to the real-world problems of a compressor design. The comparison results clearly indicate the superiority of EAs in finding tradeoffs.

关键词： aerodynamics CFD design compressor multiobjective optimization evolutionary computation gradient-based method

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Comparing Heuristic and Deterministic Approaches to Optimise Mechanical Parameters of Biopolymer Composite Materials

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MECHANICS OF ADVANCED MATERIALS AND STRUCTURES 2009年第4期16卷 293-299页

作者： Guessasma, S. Bassir, H. D. INRA NRA BIA F-44130 Nantes France FEMTO ST LMARC Besancon France

This paper compares two optimization strategies used to identify mechanical parameters associated to elasticity and plasticity behaviors of biopolymer materials. The first strategy is based on classical gradient-based methodology. It assumes that the gradient of the error between the finite element and experimental load-deflection curves is proportional to the update of mechanical parameters. The second methodology is an adaptive heuristic technique derived from genetic algorithm. It considers selection of probable solutions from the possible range of mechanical parameters. Both methodologies are used to identify Young's modulus, tangent modulus and yield stress of biopolymer composite materials exhibiting different behaviors.

关键词： finite element genetic algorithm gradient-based method biopolymer composite bending test elasticity plasticity

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A Global Optimization Technique Using gradient Information for History Matching

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ENERGY SOURCES PART A-RECOVERY UTILIZATION AND ENVIRONMENTAL EFFECTS 2014年第13期36卷 1414-1428页

作者： Monfared, A. Dehghan Helalizadeh, A. Parvizi, H. Zobeidi, K. Petr Univ Technol Dept Petr Engn Ahvaz Iran PETROXIN Ltd London England Natl Iranian South Oil Co Ahvaz Iran

The objective of the history matching process is to build reservoir models consistent with production data as well as geological constraints. A number of automatic history matching techniques have been developed in recent years. Among these methods, gradient-based history matching techniques are becoming more widely used due to their very fast convergence rate. However, they have two major drawbacks: convergence problem for a large number of parameters and local convergence of objective function. In this article, a method to resolve these two drawbacks is proposed. The proposed method takes the advantages of the gradient-based method for fast convergence. Also, it uses Latin Hypercube sampling and Levenberg-Marquardt algorithm to search the global minimum of objective function. To avoid a convergence problem, the number of parameters is reduced by sensitivity and correlation analysis. The method is validated by a case study at which observed oil rate, bottomhole pressure, gas oil ratio, and water cut are matched. The great advantage of such an approach compared to other global optimization methods is to reduce computation time and cost due to using relatively lower simulation runs and a much faster convergence rate to an optimal set of parameters using gradient information.

关键词： Latin Hypercube sampling correlation analysis Levenberg-Marquardt algorithm history matching gradient-based method

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An effective fingerprint orientation field estimation method using differential values of grayscale intensity

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PEERJ COMPUTER SCIENCE 2023年 9卷 e1342-e1342页

作者： Shen, Ting-Wei Hsu, Mao-Hsiu Shen, Chun-Hsu Wu, Wen-Fang Lu, Yu-Chiao Chu, Chia-Chun Natl Taiwan Univ Dept Mech Engn Taipei Taiwan Chihlee Univ Technol Dept Informat Management New Taipei Taiwan Ming Chuan Univ Dept Elect Engn Taoyuan Taiwan Natl Yang Ming Chiao Tung Univ Dept Comp Sci Hsinchu Taiwan Natl Cheng Kung Univ Dept Aeronaut & Astronaut Tainan Taiwan

Fingerprint orientation field (OF) estimation is important for basic fingerprint image processing and impacts the accuracy of fingerprint image enhancements, such as Gabor filters. In this article, we introduce an OF estimation algorithm based on differential values of grayscale intensity and examine the accuracy and reliability of the proposed algorithm by applying it to fingerprint images processed using Gaussian blurring and the Gaussian white noise process. The experimental results indicate that the OF estimation reliability of the proposed algorithm is higher than the gradient -based method and the power spectral density (PSD) based method in low quality fingerprints. The proposed algorithm is especially useful in noisy fingerprint images, where the OF estimation reliability of the algorithm is 6.46% and 32.93% higher than the gradientbased method and the PSD-based method, respectively.

关键词： Fingerprint gradient-based method Gaussian blurring Gabor filter Orientation field estimation

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gradient-based shape optimization for unsteady turbulent simulations using field inversion and machine learning

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AEROSPACE SCIENCE AND TECHNOLOGY 2022年 129卷

作者： Fidkowski, Krzysztof J. Univ Michigan Dept Aerosp Engn Ann Arbor MI 48109 USA

This paper presents a method for gradient-based shape optimization using unsteady models of turbulent flowfields, for which forward simulations are already expensive and adjoint calculations diverge or require costly regularization. The proposed method targets an objective and constraints computed from the time-averaged flowfield and does not use either an unsteady adjoint nor an input-to-output surrogate. The method relies on the field-inversion, machine-learning (FIML) approach, in which a correction field modifies the production term in a Reynolds-averaged Navier-Stokes (RANS) model of the flow. Steady, adjoint-based, field inversion yields this correction field, and a neural-network model is trained, only from readily-available unsteady primal data, to reproduce the field from local flow quantities. gradientbased shape optimization is then performed using the corrected RANS model, which must include a linearization of the correction field calculation for accurate gradients. The complete design optimization loop consists of iterations of unsteady simulation, FIML, and steady adjoint-based optimization. Low and moderate Reynolds number airfoil optimization problems demonstrate the performance of the proposed method, and comparisons to RANS-alone designs illustrate the importance of accounting for the unsteady flow effects in the optimization. (c) 2022 Elsevier Masson SAS. All rights reserved.

关键词： Unsteady shape optimization Field inversion Machine learning Adjoint gradient-based method Neural networks

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