• Proceedings of the KIEE Conference
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• 1992.07a
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• pp.236-238
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• 1992

This paper proposes a new algorithm to estimate time-varying parameters by combining KFSM(Kalman Filter with Shift Matrix) with neural network compansator. While the time varying parameters are estimated from KFSM, the error coverence of system, R(k) are compansated by neural network concurrently. The casestudy using computer simulation proves the usefullness and advantages of the proposed algorithm in this paper.

• Proceedings of the KIEE Conference
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• 2005.11a
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• pp.151-153
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• 2005

Indium tin oxide (ITO) thin film was polished by chemical mechanical polishing (CMP) by the change of process parameters for the improvement of electrical and optical properties of ITO thin film. Light transparent efficiency of ITO thin film was improved after CMP process at the optimized process parameters compared to that before CMP process.

• Proceedings of the KIEE Conference
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• 2002.11c
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• pp.96-99
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• 2002

This paper proposes a method to select the overshoot design parameters of the LQ-PID controller by using convex optimization in order to satisfy the design specifications. The tuning parameters of LQ-PID controller are determinated by the relationships between the design parameter to control both the overshoot and the settling time and the weighting factors Q and R in LQR.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.543-544
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• 2007

Micro-grid consists of micro-sources which adopt environmentally friendly and reliable power sources with independent real and reactive power control capability for providing premium power quality. This paper presents dynamic modeling and the stable operating range of the micro-grid system varying the parameters of the micro-sources. Case study results show the parameters affecting the stability of the micro-grid and the stable operating range of the micro-sources.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.542-543
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• 2014

In this paper, an estimation scheme based on an augmented sigma-point Kalman filter to estimate the state of charge (SOC) of the battery is presented, where the battery parameters of the series resistance ($R_o$), diffusion capacitance ($C_1$) and resistance ($R_1$) are also estimated through the recursive least squares (RLS) for better accuracy of the SOC. The effectiveness of the proposed method is verified by simulation results.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.686-688
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• 1993

This paper proposes a robust speed control algorithm of Induction Motor. The main idea of this paper is to compensate the torque component of motor current with load torque observer and feedforward control. The speed response of the conventional PI controller is affected by variation of system parameters. However the proposed system has robust characteristics against the variation of system parameters. The simulation results and experiment prove the validity of proposed algorithm.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.1
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• pp.24-29
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• 2005

Chemical mechanical polishing (CMP) has been widely accepted for the global planarization of multi-layer structures in semiconductor manufacturing. Copper has been the candidate metallization material for ultra-large scale integrated circuits (ULSIs), owing to its excellent electro-migration resistance and low electrical resistance. However, it still has various problems in copper CMP process. Thus, it is important to understand the effect of the process variables such as turntable speed, head speed, down force and back pressure are very important parameters that must be carefully formulated in order to achieve desired the removal rates and non-uniformity. Using a design of experiment (DOE) approach, this study was performed investigating the main effect of the variables and the interaction between the various parameters during CMP. A better understanding of the interaction behavior between the various parameters and the effect on removal rate, non-uniformity and ETC (edge to center) is achieved by using the statistical analysis techniques. In the experimental tests, the optimum parameters which were derived from the statistical analysis could be found for higher removal rate and lower non-uniformity through the above DOE results.

• Journal of IKEEE
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• v.23 no.1
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• pp.318-321
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• 2019

The apparent soil resistivity is used for estimating multilayer soil parameters, such as, layer's depth and soil resistivity. The apparent soil resistivity can be measured, and also can be calculated if soil parameters are given, becacuse the apparent soil resistivity is a function of these parameters. Therefore, any optimization algorithms can be used to find these parameters which make the calculated apparent soil resistivity close to the measured one. The equation for calculating the apparent soil resistivity is complicated and time consumed, because it is composed of an infinite integral which includes a zero order Bessel's function of the first kind. In this paper, a fast algorithm for calculating the apparent soil resistivity of horizontal multilayer earth structure has been presented using complex image method.

• Journal of Magnetics
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• v.19 no.4
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• pp.399-403
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• 2014

We designed an ultra-high frequency (UHF: 300MHz to 3 GHz) ferrite circulator to investigate magnetic parameters, which are suitable for a self-biased GHz circulator design. The size of the ferrite disk was 1.58 mm in thickness and 13.5 mm in diameter. The saturation magnetization ($4{\pi}M_s$) of 3900 Gauss, internal magnetic field ($H_{in}$) of 1 kOe, and ferromagnetic linewidth (${\Delta}H$) of 354 Oe were used in circulator performance simulation. The simulation results show the isolation of 36.4 dB and insertion loss of 2.76 dB at 2.6 GHz and were compared to measured results. A Ni-Zn ferrite circulator was fabricated based on the above design parameters. An out-of-plane DC magnetic field ($H_0$) of 4.8 kOe was applied to the fabricated circulator to measure isolation, insertion loss, and bandwidth. Experimental magnetic parameters for the ferrite were $H_{in}$ of about 1.33 kOe and $4{\pi}M_s$ of 3935 Gauss. The isolation 43.9 dB and insertion loss of 5.6 dB measured at 2.5 GHz are in close agreement with the simulated results of the designed ferrite circulator. Based on the simulated and experimental results, we demonstrate that the following magnetic parameters are suitable for 2 GHz self-biased circulator design: $4{\pi}M_r$ of 3900 Gauss, $H_a$ of 4.5 kOe, $H_c$ greater than 3.4 kOe, and ${\Delta}H$ of 50 Oe.

• Proceedings of the KIEE Conference
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• 1991.11a
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• pp.249-252
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• 1991

I-V characteristics of LIGBT is studied by SPICE simulation which includes device parameters and process parameters. Analysis and modeling of ON-resistance are discussed in this paper. Compare with experimental values, SPICE simulation and modeling results show that our simulation is valid for LIGBT.