• 제어로봇시스템학회논문지
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• 제8권9호
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• pp.812-817
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• 2002

This paper presents a development of high accuracy aligner and describes a method to find the orientation of a substantially circular disk shaped wafer with at least one flat region on an edge thereof. In the developed system, the wafer is spun one 360 degree turn on a chuck and the edge position is measured by a linear array to obtain a set of data points at various wafer orientation. The rotation axis may differ from wafer center by an unknown eccentricity. The flat angle is found by fitting a cosine curve to the actual data to obtain a deviation. The maximum deviation is then corrected for errors due to a finite number of data points and wafer eccentricity by calculating an adjustment angle from data points on the wafer fiat. After determining the flat angle the wafer is spun to the desired orientation. The wafer eccentricity can be calculated from four of the data points located away from the flat edge region. and the wafer is then centered.

• Bulletin of the Korean Chemical Society
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• 제30권9호
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• pp.2001-2006
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• 2009

Temperature dependence of the critical micelle concentration (CMC), $x_{CMC}$, in micellization can be described by ln $x_{CMC}$ = A + BT + C lnT + D/T, which has been derived statistical-mechanically. Here A, B, C, and D are fitting parameters. The equation fits the CMC data better than conventionally used polynomial equations of temperature. Moreover, it yields the unique(exponent) value of 2 when the CMC is expressed in a power-law form. This finding is quite significant, because it may point to the universality of the thermal behavior of CMC. Hence, in this article, the nature of the equation ln $x_{CMC}$ = A + BT + C lnT + D/T is examined from a lattice-theory point of view through the Flory-Huggins model. It is found that a linear behavior of heat capacity change of micellization is responsible for the CMC equation of temperature.

• 대한조선학회논문집
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• 제44권1호
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• pp.32-39
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• 2007

A three-dimensional finite element model has been developed to simulate the MIG P/S welding process of two aluminum plates. The finite element calculations are performed using ANSYS finite element code, which takes into account the thermal and mechanical non-linear material properties. The results of finite element analysis compared with those of experiment to show its validity in view of distortions. Parametric studies are carried out on the validated model to assess the effects of various factors on the final residual distortion. Large deformations, temperature dependent material properties are included in the model. Finally, the formulas of fitting curves of angular distortion transverse shrinkage, and longitudinal shrinkage have been proposed.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 제14회 신호처리 합동 학술대회 논문집
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• pp.411-414
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• 2001

목표물 인식(Target Recognition)에 사용되는 대표적인 특징 정보에는 밝기 (Intensity) 정보와 윤곽선(Boundary) 등의 모양(Shape) 정보가 있다. 그러나, 일반적으로 영상에서 바로 추출한 밝기 정보나 윤곽선 정보는 환경 변화에 의한 많은 오차 요인들을 포함하고 있기 때문에, 이들 특징 정보를 개별적으로 인식에 사용하는 것은 높은 인식 성능을 기대하기 어렵다. 따라서, 밝기 정보와 모양 정보를 인식에 함께 사용하는 기법이 요구된다. 본 논문에서는 밝기 정보와 윤곽선 기반의 모양 정보를 합성하여 동시에 인식에 사용하는 3단계 기법을 제안한다. 제안하는 기법에서 밝기 정보 추출에 는 PCA (Principal Component Analysis)기법을 사용하고 , 윤곽선 정보 추출에는 PDM(Point Distribution Model) 에 기반한 영역 분할(Segmentation) 기법과 Algebraic Curve Fitting기법을 사용하였다 추출된 밝기 정보와 윤곽선 정보는 FLD(Fisher Linear Discriminant) 기법을 통해 결합(integration)되어 인식에 사용 된다. 제안한 기법을 적외선 자동차 영상을 인식하는 실험에 적용한 결과, 기존기법에 비해 인식 성능이 개선됨을 확인할 수 있었다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 춘계학술대회 논문집
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• pp.508-512
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• 2004

An ultra-sharp tungsten electrode for field emission was manufactured by using an electrochemical etching method, and its beam characteristics were investigated. KOH and NaOH were the electrolytes used in this research, and the taper length of the tip varied form 150 $\mu\textrm{m}$ to 250 $\mu\textrm{m}$ according to the applied voltage and the concentration of the electrolyte. The electron-beam stability was measured to be within 5% for a total emission current of 5 ${\mu}\textrm{A}$ during 4 hours of operation, and the Ignition voltages were found to be ∼300 V. The tip radius was experimentally found to be 250${\AA}$ from a linear fitting of Fowler-Nordheim plots, which was in remarkably good agreement with that of the image size from scanning ion-microscopy.

• 대한산업공학회지
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• 제17권1호
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• pp.37-49
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• 1991

This report describes an integrated approach to sculptured surface design and manufacture, and a software package for it on a multi-axis NC milling machine. The integrated software consists of four parts : (1) surface fitting procedure for generating the characteristic polyhedron from 3 dimensional CMM data, (2) surface description for generating the mathematical representation of sculptured surfaces. (3) tool path generation for approximating the surface representation into a sequence of linear cutter paths, and (4) tool control for generating the corresponding joint variable values. This integrated approach is generally applicable to sculptured surface manufacturing where multi-axis milling machines are necessary to produce smooth three-dimensional surfaces.

• Communications for Statistical Applications and Methods
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• 제22권1호
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• pp.41-54
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• 2015

In this article, we propose nonconcave penalties on a reduced-rank regression model to select variables and estimate coefficients simultaneously. We apply HARD (hard thresholding) and SCAD (smoothly clipped absolute deviation) symmetric penalty functions with singularities at the origin, and bounded by a constant to reduce bias. In our simulation study and real data analysis, the new method is compared with an existing variable selection method using $L_1$ penalty that exhibits competitive performance in prediction and variable selection. Instead of using only one type of penalty function, we use two or three penalty functions simultaneously and take advantages of various types of penalty functions together to select relevant predictors and estimation to improve the overall performance of model fitting.

• Industrial Engineering and Management Systems
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• 제8권3호
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• pp.148-154
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• 2009

In recent days, large-sized flat-panel display (FPD) has been increasingly applied to computer monitors and TVs. Mura defects, appearing as low contrast or non-uniform brightness region, sometimes occur in manufacturing of the Thin-Film Transistor Liquid-Crystal Displays (TFT-LCD). Implementation of automatic Mura inspection methods is necessary for TFT-LCD production. Various existing Mura detection methods based on regression diagnostics, surface fitting and data transformation have been presented with good performance. This paper proposes an efficient Mura detection method that is based on a regression diagnostics using studentized residuals for automatic Mura inspection of FPD. The input image is estimated by a linear model and then the studentized residuals are calculated for filtering Mura regions. After image dilation, the proposed threshold is determined for detecting the non-uniform brightness region in TFT-LCD by means of monitoring the every pixel in the image. The experimental results obtained from several test images are used to illustrate the effectiveness and efficiency of the proposed method for Mura detection.

• 한국정밀공학회지
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• 제9권1호
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• pp.96-105
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• 1992

A study on the construction of a CAD/CAM system operated by 16 Bit PC basic language, for machining sculptured surface of die, was carried out. The system consists of 2 steps i.e., process for geometric modelling by wire frame and process for machining data generation. Geometric modelling for sculptured surface is made by the point data fitting, parallel sweeping, normal sweeping and linear connection of cross section curve. Machining data are gained by cutter off-set of geometric model data and machining carried out by DNC. This system is to be proved enough for rough cutting by actual machining experiment. But, for becoming a high level system, another method of cutter off-set has to be regarded and system must be reconstructed by another program language.

• 한국임상수의학회지
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• 제21권3호
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• pp.286-290
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• 2004

Cytogenetic and hematological analysis was performed in peripheral blood of pig in the vicinity of Yeonggwang nuclear power station and control area. The frequency of micronuclei (MN) in peripheral blood lymphocytes from pig was used as a biomarker of radiobiological effects resulting from exposure to environmental radiation. An estimated dose of radiation was calculated by a best fitting linear-quadratic model based on the radiation-induced MN formation from the swine lymphocytes exposed in vitro to radiation over the range from 0 Gy to 4 Gy. MN rates in lymphocytes of pig from Yeonggwang nuclear power station and control area were 10.60/1,000 and 11.10/1,000, respectively. There were no significant differences in MN frequencies and hematological values in pig between Yeonggwang and control area. The study indicates that the MN assay in lymphocyte of pig is a rapid, sensitive and accurate method that can be used to monitor a large population exposed to radiation.