• Proceedings of the KIEE Conference
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• 2007.04c
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• pp.100-102
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• 2007

In this paper, a modified multi-level convert for low cost high speed switched reluctance (SR) drive is proposed The proposed multi-level converter has reduced number of power switches and diodes than that of a conventional asymmetric converter for SRM, and lower voltage rating of the dump capacitor comparing with energy efficient c-dump converter. It can supply five operating modes that is boosted, DC-link, zero, negative bias and negative boosted voltage. The proposed multi-level converter has fast excitation and demagnetization modes of phase current, so dynamic response can be achieved. The proposed multi-level converter is verified by computer simulation and experimental results.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1450-1455
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• 2005

This paper describes a DR construction for land navigation and the sigma point based receding horizon Kalman FIR (SPRHKF) filter for DR/GPS hybrid navigation system. A simple DR construction is adopted to improve the performance both of the pure land DR navigation and the DR/GSP hybrid navigation system. In order to overcome the flaws of the EKF, the SPKF is merged with the receding horizon strategy. This filter has several advantages over the EKF, the SPKF, and the RHKF filter. The advantages include the robustness to the system model uncertainty, the initial estimation error, temporary unknown bias, and etc. The computational burden is reduced. Especially, the proposed filter works well even in the case of exiting the unmodeled random walk of the inertial sensors, which can be occurred in the MEMS inertial sensors by temperature variation. Therefore, the SPRHKF filter can provide the navigation information with good quality in the DR/GPS hybrid navigation system for land navigation seamlessly.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.518-521
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• 1998

This paper describes a 3.3V-65MHz 12BIT CMOS current-mode DAC designed with a 8 MSB current matirx stage and a 4 LSB binary weighting stage. The linearity errors caused by a voltage drop of the ground line and a threshold voltage mismatch of transistors have been reduced by the symmetrical routing method with ground line and the tree structure bias circuit, respectively. In order to realize a low glitch energy, a cascode current switch ahs been employed. The simulation results of the designed DAC show a coversion rate of 65MHz, a powr dissipation of 71.7mW, a DNL of .+-.0.2LSB and an INL of .+-.0.8LSB with a single powr supply of 3.3V for a CMOS 0.6.mu.m n-well technology.

• Journal of the Korean Data and Information Science Society
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• v.14 no.4
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• pp.965-974
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• 2003

In this paper we propose an incremental classification of multi-class data set by LS-SVM. By encoding the output variable in the training data set appropriately, we obtain a new specific output vectors for the training data sets. Then, online LS-SVM is applied on each newly encoded output vectors. Proposed method will enable the computation cost to be reduced and the training to be performed incrementally. With the incremental formulation of an inverse matrix, the current information and new input data are used for building another new inverse matrix for the estimation of the optimal bias and lagrange multipliers. Computational difficulties of large scale matrix inversion can be avoided. Performance of proposed method are shown via numerical studies and compared with artificial neural network.

• Journal of the Korean Institute of Telematics and Electronics
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• v.22 no.4
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• pp.1-7
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• 1985

In this paper, a more improved threshold voltage model dependent on drain voltage and substrate bias for short - channel enhancement - mode IGFET is presented. Especially, compared with the several recently published models, the error is sufficiently reduced with the precise analysis on the correction factor for short-channel effect and the calculated values using this model are also agreed well with the experimental data about 1$\mu$m - channel length device.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.2
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• pp.47-54
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• 1992

In this paper, a new extended JPDA (Joint Probabilistic Data Association) tracking algorithm which has more excellent performance than that of the conventional JPDA algorithm in case of the tracking of crossing targets is proposed. In the proposed extended JPDA algorithm, the velocity parameters as well as the position parameters are included to compute the association probabilities between tracks and measurement data. Then the tracking performance of crossing targets is improved and the track bias of parallel moving targets can be reduced. Accordingly, in this paper, the new extended JPDA algorithm for multitarget tracking is proposed and its good performance is shown through the computer simulation. And, tracking performance of extended JPDA algorithm is also compared with that of JPDA algorithm with our noise model.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.1
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• pp.58.1-58.1
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• 2017

National Youth Space Center has recently founded the Deokheung Optical Astronomy Observatory (DOAO) 1m Telescope, which accepts community observing applications since 2016. Standardization and calibration of the new observing facility are essential for astronomical research. In this poster, we present standardization processes and preliminary results for photometry of the Johnson-Cousins BVRI filter system. We selected sample data from a night in stable weather condition. After bias, dark, and flat corrections and photometry using ccdred and daophot package of IRAF, we derived standardized band pass parameters including color terms. The corrected photometry results of the BVRI filter system show reduced deviations from the standard magnitudes in the literature. In addition, we calculated atmospheric extinction coefficients and limiting magnitudes of the telescope system. We plan to extend these standardizing processes to flux calibration of narrow band filters, e.g. $H{\alpha}$ filter.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.05a
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• pp.90-93
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• 1996

The conduction mechanisms of the off-current in low temperature ($\leq$600$^{\circ}C$) processed polycrystalline silicon thin film transistors (LTP poly-Si TFT's) has been systematically studied. Especially, the temperature and bias dependence of the off-current between unpassivated and passivated poly-Si TFT's was investigated and compared. The off-current of unpassivated poly-Si TFT's is due to a resistive current at low gate and drain voltage, thermal emission current at high gate, low drain voltage, and field enhanced thermal emission current in the depletion region near the drain at high gate and drain voltage. After hydrogenation, it was observed that the off-currents were remarkably reduced by plasma-hydrogenation. It was also observed that the off-currents of the passivated poly-Si TFT's are more critically dependent on temperature rather than electric field.

• Communications for Statistical Applications and Methods
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• v.23 no.2
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• pp.179-187
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• 2016

The fixed effects panel probit model faces "incidental parameters problem" because it has a property that the number of parameters to be estimated will increase with sample size. The maximum likelihood estimation fails to give a consistent estimator of slope parameter. Unlike the panel regression model, it is not feasible to find an orthogonal reparameterization of fixed effects to get a consistent estimator. In this note, a hierarchical Bayesian model is proposed. The model is essentially equivalent to the frequentist's random effects model, but the individual specific effects are estimable with the help of Gibbs sampling. The Bayesian estimator is shown to reduce reduced the small sample bias. The maximum likelihood estimator in the random effects model is also efficient, which contradicts Green (2004)'s conclusion.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.289-292
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• 2005

New poly-Si TFTs have been proposed and fabricated in order to increases the output channel resistance ($r_o$). The counter-doped($p^+$) source is tied to the $n^+$ source and is extended into the channel region so that it employs the reverse bias depletion in the channel. As $V_{DS}$ is increased, the depletion width is increased and the effective channel width is reduced. Therefore, the output current saturates well and the $r_o$ is increased successfully. The proposed CMOS devices may improve the amplifier gain of data driver in active-matrix displays