• Journal of the Korea Institute of Information and Communication Engineering
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• v.1 no.2
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• pp.183-191
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• 1997

A neural network-based algorithm for the static weapon-target assignment (WTA) problem is Presented in this paper. An optimal WTA is one which allocates targets to weapon systems such that the total expected leakage value of targets surviving the defense is minimized. The proposed algorithm is based on a Hopfield and Tank's neural network model, and uses K x M processing elements called binary neuron, where M is the number of weapon platforms and K is the number of targets. From the software simulation results of example battle scenarios, it is shown that the proposed method has better performance in convergence speed than other method when the optimal initial values are used.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1994.05a
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• pp.123-126
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• 1994

We discussed the thermal analysis for recording media with the variation of the laser pulse duration and the power and the temperature distribution for the optimized Te-based antireflection structure by using the computer calculations. If the radial diffusion of heat is negligible, we can calculate the maximum temperature at the spot center in recording layer by Simple Method, and the temperature profile considering the specific heat and the latent heat by Numerical Method. As a result, the effect of the heat sinking which acted as a loss for the hole formation can be minimized by introducing the pulse of the hole formation duration( $\tau$ ) shorter than the thermal time constant( $\tau$$\sub$D/) of dielectric layer. This requirments can be satisfied as using the dielectric thickness of the 7nd ART condition or the dielectric materials with low thermal diffusivity.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.774-776
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• 2003

In this paper the controlled closing algorithm to locate contact touch instants within the span in which the making voltage is minimized is proposed with the characteristics of circuit breakers such as RDDS(rate of decrease of dielectric strength) and a mechanical operating tolerance taken into account. The analytic results on the voltages across circuit breaker terminals upon closing operation play an important roles as references to describe the suggested method. Even though in the case of the isolated neutral capacitor banks, it is possible to decide the optimum contact instants without any dedicated procedures.

• Journal of Power Electronics
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• v.10 no.4
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• pp.357-364
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• 2010

In this paper, a novel analysis of a carrier based PWM method for multilevel inverters is presented. The space vector PWM and carrier based PWM correlations in multilevel inverters are investigated in a nominal two-level switching diagram. The obtained results can be applied to design various carrier PWM techniques. In this paper, a carrier based single-state PWM technique, which reduces the switching number and optimizes the active voltage errors, is presented. This PWM technique can be advantageous if there are a large number of levels. The proposed method is mathematically formulated and demonstrated by simulations and experimental results.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.2
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• pp.298-303
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• 2016

In this paper, the vibration source of IPM type BLDC motor was analyzed by finite element method. The main causes of the electrical vibration were RMF(Radial magnetic force) and cogging torque. It was designed model of minimized cogging torque and RMF equilibrium. Design models were selected the optimum model using the design of experiment method. And, the vibration experiment was carried out through prototype machine of each model. Finally, the experimental results were compared with the analysis ones.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.3
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• pp.275-280
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• 2005

Recently there has been a growing interest in the design and manufacturing of the muffler tube due to the strict environment regulations, A muffler is an important part used to reduce noise and to purify exhaust gas in cars and heavy equipment. The shape of the muffler tube and the number of the tube hole has been made variously according to the weight and function of the car. The perforating technique of the muffler tube has a great influence on the manufacturing cost. In this study, metal forming analysis has been carried out to investigate the perforating process for the muffler tube and predict an optimal forming conditions of the muffler tube, Also its simulation results by the finite element method were reflected to the die design and the manufacturing system for the muffler tube. The perforating process is performed in the longitudinal direction of the tube. According to the simulation results, when the shear angle of punch was similar to the tube curvature, the optimal shape was obtained. Also when the clearance of die was 0.2mm, the burr was minimized and optimal shear section was obtained.

• Fire Science and Engineering
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• v.20 no.4 s.64
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• pp.19-25
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• 2006

In this paper, a new design of the sprinkler branch outlet for fire-extinguishing purposes is presented together with its manufacturing process. The conventional three-piece design is improved by a new one-piece design with the help of the manufacturing technology of cold forging. The forging process is simulated and optimized by the rigid-plastic finite element method and the design tryouts are thus minimized. It has been shown through its applications that the presented system is much more economical and structurally stronger.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2006.03a
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• pp.401-408
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• 2006

An optimum design method for hybrid control systems is proposed in this study. By considering both active and passive control systems as a combined or a hybrid system, the optimization of the hybrid system can be achieved simultaneously. In the proposed approach, we consider design parameters of active control devices and the elements of the feedback gain matrix as design variables for the active control system. Required quantity of the added dampers are also treated as design variables for the passive control system. In the proposed method, the cost of both active and passive control devices, the required control efforts and dynamic responses of a target structure are selected as objective functions to be minimized. To effectively address the multi-objective optimization problem, we adopt a preference-based optimization model and apply a genetic algorithm as a numerical searching technique. As an example to verify the validity of the proposed optimization technique, a wind-excited 20-storey building with hybrid control systems is used and the results are presented.

• Earthquakes and Structures
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• v.12 no.4
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• pp.389-395
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• 2017

In this paper a simple approach is presented for spectral matching of ground motions utilizing the wavelet transform and a recently developed metaheuristic optimization technique. For this purpose, wavelet transform is used to decompose the original ground motions to several levels, where each level covers a special range of frequency, and then each level is multiplied by a variable. Subsequently, the vibrating particles system (VPS) algorithm is employed to calculate the variables such that the error between the response and target spectra is minimized. The application of the proposed method is illustrated through modifying 12 sets of ground motions. The results achieved by this method demonstrate its capability in solving the problem. The outcomes of the VPS algorithm are compared to those of the standard colliding bodies optimization (CBO) to illustrate the importance of the enhancement of the algorithm.

• Membrane and Water Treatment
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• v.9 no.2
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• pp.129-136
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• 2018

In this contribution, the control of multivariable reverse osmosis (RO) desalination plant using proportional-integral-derivative (PID) controllers is presented. First, feed-forward compensators are designed using simplified decoupling method and then the PID controllers are tuned for flux (flow-rate) and conductivity (salinity). The tuning of PID controllers is accomplished by minimization of the integral of squared error (ISE). The ISEs are minimized using a recently proposed algorithm named as teacher-learner-based-optimization (TLBO). TLBO algorithm is used due to being simple and being free from algorithm-specific parameters. A comparative analysis is carried out to prove the supremacy of TLBO algorithm over other state-of-art algorithms like particle swarm optimization (PSO), artificial bee colony (ABC) and differential evolution (DE). The simulation results and comparisons show that the purposed method performs better in terms of performance and can successfully be applied for tuning of PID controllers for RO desalination plants.