• Journal of Power Electronics
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• v.18 no.4
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• pp.1099-1110
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• 2018

In this paper, a loss minimization control method for interior permanent magnet synchronous motors is presented with considering self-saturation and cross saturation. According to variation of the d-axis and q-axis inductances by different values of the d-axis and q-axis components of currents, it is necessary to consider self-saturation and cross saturation in the loss minimization control method. In addition, the iron loss resistance variation due to frequency variation is considered in the condition of loss minimization. Furthermore, the loss minimization control method is compared with maximum torque per ampere (MTPA), unity power factor (UPF) and $i_d=0$ control methods. Experimental results verify the performance and proper dynamic response of the loss minimization control method with considering self-saturation and cross saturation.

• Journal of Korea Society of Industrial Information Systems
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• v.16 no.5
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• pp.9-19
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• 2011

In many instances a concise form of logic is often required for building today's complex systems. The method described in this paper can be used for a wide range of industrial applications that requires Boolean type of logic minimization. Unlike some of the previous logic minimization methods, the proposed method can be used to better gain insights into the logic minimization process. Based on the decimal valued matrix, the method described here can be used to find an exact minimized solution for a given Boolean function. It is a visual based method that primarily relies on grouping the cell values within the matrix. At the same time, the method is systematic to the extent that it can also be computerized. Constructing the matrix to visualize a logic minimization problem should be relatively easy for the most part, particularly if the computer-generated graphs are accompanied.

• Bulletin of the Korean Mathematical Society
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• v.53 no.2
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• pp.589-600
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• 2016

In this paper, we propose a new incremental gradient method for solving a regularized minimization problem whose objective is the sum of m smooth functions and a (possibly nonsmooth) convex function. This method uses an adaptive stepsize. Recently proposed incremental gradient methods for a regularized minimization problem need O(mn) storage, where n is the number of variables. This is the drawback of them. But, the proposed new incremental gradient method requires only O(n) storage.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.6
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• pp.1140-1145
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• 2011

This paper proposes a new loss minimization control method for the vector controlled induction motors. The aim of the proposed loss minimization method is how to determine the optimal flux reference to minimize the total loss of induction motor. Even though the proposed algorithm is based on the equivalent circuit of induction motor including iron loss and leakage inductance, the algorithm is easy to be found and simple to be implemented. Futhermore, the proposed loss minimization algorithm can be applied easily to the traditional vector control system without any additional hardware. Simulation and experimental results are given to validate the effectiveness of the proposed method.

• Journal of information and communication convergence engineering
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• v.5 no.1
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• pp.54-58
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• 2007

A real-time frame-layer rate control algorithm with a token bucket traffic shaper is proposed for distortion variation minimization. The proposed rate control method uses a non-iterative optimization method for low computational complexity, and performs bit allocation at the frame level to minimize the average distortion over an entire sequence as well as variations in distortion between frames. The proposed algorithm does not produce time delay from encoding, and is suitable for real-time low-complexity video encoder. Experimental results indicate that the proposed control method provides better visual and PSNR performances than the existing rate control method.

• Journal of the Korean Institute of Telematics and Electronics
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• v.22 no.2
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• pp.82-89
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• 1985

A new non-inferior solution is obtained by investigating method of weight p- norm to explain the conception of MCO (multiple criterion optimization) problem. And then the optimum non-inferior solution is obtained by the weight minimization method applied to objective function of MOSFET NAND rATEAlso this weight minimization method using weight P- norm methods can be applied to non-convex objective function. The result of this minimization method shows the efficiency in comparison with that of Lightner.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.10a
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• pp.231-236
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• 1996

Recently to develope an automobile with better properties, much researches and investments are executed in many countries. In this paper, the weight of an engine block intend to minimize without changing the natural frequency. The weight minimization of an engine block is started from much less initial thickness than original thickness of the model and performed by using the sensitive analysis method and the optimum structural modification method. It can be considered that the weight minimization is completed through this process, because the optimum structural modification method includes the constraint of minimum changing quantity.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.1167-1172
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• 1990

This paper discusses a force distribution scheme which minimizes the weighted norm of the forces/torques applied on weak points of cooperating multiple robot arms. The scheme is proposed to avoid the damage or unwanted motion of any weak point of robots or object stemming from excessive forces/torques. Since the proposed scheme can be used for either the joint torque minimization or the exerted force minimization on the object, it can be regarded as a unified force minimization method for multiple robot arms. The computational complexity in this scheme is analyzed using the properties of Jarcobian. Simulation of two identical PUMA robots held an object is carried out to illustrate the proposed scheme. By the proper choice of the weighting matrix in the performance index, we show that force minimization for a weak point can be achieved, and that the exerted force minimization on the object can be changed to the joint torque minimization.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.8
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• pp.2053-2061
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• 1994

The static and fatigue tensile tests have been conduted to predict the fatigue life of 8-harness satin woven and plain woven carbon/epoxy composite plates containing a circular hole. A fatigue residual strength degradation model, based on the assumption that the residual strength for unnotched specimen decreases monotonically, has been applied to predict statistically the fatigue life of materials used in this study. To determine the parameters(c, b and K) of the residual strength degradation model, the minimization technique and the maximum likelihood method are used. Agreement of the converted ultimate strength by using the minimization technique with the static ultimate strength is reasonably good. Therefore, the minimization technique is more adjustable in the determination of the parameter and the prediction of the fatigue life than the maximum likelihood method.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.7
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• pp.997-1004
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• 1990

In this paper, a design method of a robust adaptive regulator with feedfoward path based on the explicit criterion minimization is proposed. The convergence speed of parameter estimation is improved by using the stochastic Newton minimization method in the criterion minimization algorithm, and sensitivity derivatives are used in the regulator calculation for improving the robustness of the control system. Trh proposed adaptive regulator is applied to the stable minimum-phase and nonminimum-phase system, the results are shown that control performance and disturbance compensation ability of the regulator are improved. And the choosing method of input penalty is proposed.