• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.3
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• pp.1-8
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• 1996

This paper proposes a novel transversal filter and an optimal LMS algorithm, and show how these can be realized as an adaptive equalizer. The transversal filter consists of a walsh and block pulse functions. in the LMS algorithm with equalizers, the convergence factor is an improtant design parameter because it governs stability and convergence speed. The conventional adaptation techniques use a fixed time constant convergence factor by the trial and error method. In this paper, an optimal method in the choice of the convergence factor is proposed. The proposed algorithm is obtrained that is tailored for each filter tap and is updated at each iteration. The performance of the proposed algorithm is compared iwth those of the conventional TDL and DFT equalizers by computer simulations.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.8
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• pp.598-608
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• 2002

This paper shows the optimal design methodology for the fluid engine mount by the artificial life algorithm. The design has been commonly modified by trial and error because there is many design parameters that can be varied in order to minimize transmissibility at the desired fundamental resonant and notch frequencies. The application of trial and error method to optimization of the fluid mount is a great work. Many combinations of parameters are possible to give us the desired resonant and notch frequencies, but the question is which combination Provides the lowest resonant peak and notch depth. In this study the enhanced artificial life algorithm is applied to get the desired fundamental resonant and notch frequencies of a fluid mount and to minimize transmissibility at these frequencies. The present hybrid algorithm is the synthesis of and artificial life algorithm with the random tabu (R-tabu) search method. The hybrid algorithm has some advantages, which is not only faster than the conventional artificial life algorithm, but also gives a more accurate solution. In addition, this algorithm can find all globa1 optimum solutions. The results show that the performance of the optimized mount compared with the original mount is improved significantly.

• Journal of Mechanical Science and Technology
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• v.20 no.8
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• pp.1125-1138
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• 2006

The optimal design of the squeeze film damper (SFD) for rotor system has been studied in previous researches. However, these researches have not been considering jumping or nonlinear phenomena of a rotor system with SFD. This paper represents an optimization technique for linear and nonlinear response of a simple rotor system with SFDs by using a hybrid GA-SA algorithm which combined enhanced genetic algorithm (GA) with simulated annealing algorithm (SA). The damper design parameters are the radius, length and radial clearance of the damper. The objective function is to minimize the transmitted load between SFD and foundation at the operating and critical speeds of the rotor system with SFD which has linear and nonlinear unbalance responses. The numerical results show that the transmitted load of the SFD is greatly reduced in linear and nonlinear responses for the rotor system.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.49 no.3
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• pp.111-116
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• 2000

In this paper, we presented a new algebraic iterative algorithm for the optimal control of the nonlinear systems. The algorithm is based on tow steps. The first step transforms optimal control problem into a sequence of linear optimal control problem using the quasilinearization method. In the second step, TPB(two point boundary condition problem) is solved by algebraic equations instead of differential equations using BPF(block pulse functions). The proposed algorithm is simple and efficient in computation for the optimal control of nonlinear systems. In computer simulation, the algorithm was verified through the optimal control design of Van del pole system and Volterra Predatory-prey system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.1
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• pp.155-163
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• 2000

In this paper, we propose an algorithm for the object function used in optimal control or optimal design that sets the object function as simultaneous and then calculates the optimal value according to the Newton method. The proposed method calculates the optimal value simply using two inputs; object function and initial value, using the DDA(Direct Derivative Algorithm) which is a programmed ordinary derivative function that does not inquire the calculation of derivative function nor any inputs. And we have verified the usefulness of the algorithm for the optimal control and optimal dosing.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.9
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• pp.859-865
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• 1991

This paper presents a new shaoe optimal design method using Desing Sensitivity Analysis. Design Sensitivity, defined as the variation of the object function with respect to the design variables, is based on the total differentiation of the matrix equation obtained from discretization of governing equations with respect to design variables. Analysis of the various characteristics adn calculation of Design Sensitivity of optimization model are achieved by using finite or boundary element methods. The proposee algorithm is applied to the optimal shape design of high voltage electrode under specified conditions. It is shown, from the numerical results, that the algorithm is very useful for the optimal shape design of electric apparatus.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.5
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• pp.125-132
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• 2008

Structural optimization is widely adopted in the design of structures with the development of computer aided design and computer technique recently. By applying the structural optimization in the last decades, designers have gained the design scheme of structures more feasibly and easily. In this paper, an optimal design of one 30-story high rise steel structure is performed considering material non-linearity. Based on finite element analysis and adaptive simulated annealing algorithm, the optimal weight of structure is derived under constraints of allowable yield stress, shear stress and serviceability.

• Journal of Aerospace System Engineering
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• v.9 no.4
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• pp.55-61
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• 2015

In this study, we peformed optimal design of a composite skid landing gear, one of the solid spring shock absorbers, for light vertical takeoff and landing aircraft. Although a solid spring type has poor energy dissipation capability, it is commonly used for light aircraft where sink speeds are low and shock absorption is non-critical in terms of simplicity, low cost and weight reduction. In this paper, design parameters of solid spring such as sink speed, gear leg length, deflection and landing load factor were reviewed. In order to meet structural requirements such as deflection and strength, finally, we conducted optimal design of the composite skid landing gear for VTOL UAV using genetic algorithm and pattern search algorithm.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2001.05a
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• pp.225-230
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• 2001

In this paper, a method for optimal design of PID controller using the immune algorithm(IA) has been proposed to improve the stability of A.C.-D.C. power system. The process of this study is composed of formulation of basic controls on HVDC transmission system, mathematical model preparation for stability analysis, and supplementary signal control by an optimal PID controller using the IA. The dynamic property was verified through computer simulations regarding transient stability.

• Structural Engineering and Mechanics
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• v.58 no.3
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• pp.533-553
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• 2016

In this paper, the recently developed meta-heuristic algorithm called tug of war optimization is applied to optimal design of castellated beams. Two common types of laterally supported castellated beams are considered as design problems: beams with hexagonal openings and beams with circular openings. Here, castellated beams have been studied for two cases: beams without filled holes and beams with end-filled holes. Also, tug of war optimization algorithm is utilized for obtaining the solution of these design problems. For this purpose, the minimum cost is taken as the objective function, and some benchmark problems are solved from literature.