• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1998년도 춘계학술대회논문집
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• pp.254-257
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• 1998

The twisting and the bending of extruded product are caused by the shapes of products and by the shapes of die surfaces and by the shapes of die land. Because the elliptical shape and the circular shape of the extruded product have the symmetry line of cross-section area, the twisting and the bending of product has not occurred. But the analysis by the DEFORM-3DTM show that the twisting and the bending of extruded product can be occurred by the twisting of the twisting of the die land and by the curving of the die land. The results by the analysis show that the twisting angle of the extruded procduct increases by the twisting angle of the die land and the curvature of the extruded products increases by the radius of bending of the die land.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 심포지엄 논문집 정보 및 제어부문
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• pp.234-236
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• 2006

Because of its long measurement range and ultra-precise resolution. the heterodyne laser interferometer systems are very common in various industry area such as semiconductor manufacturing. However the periodical nonlinearity property caused from frequency mixing is an obstacle to improve the high measurement accuracy in nanometer scale. In this paper to minimize the effect of nonlinearity, we propose an adaptive nonlinearity compensation algorithm. We first compute compensation parameters using least square (LS) with the capacitance displacement sensor as a reference input. We then update the parameters with recursive LS (RLS) while the values are optimized to modify the elliptical phase into circular one. Through comparison with some experimental results of laser system, we demonstrate the effectiveness of our proposed algorithm.

• 한국통신학회논문지
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• 제21권8호
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• pp.1874-1884
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• 1996

In this paper, we proposed automatic searching algorithm of thresholding value using multilevel thresholding for face segmentation from input bust image effectively. The proposed algorithm extracted the thresholding value of brightness that is formed background region, face region and hair region without illumination, background and face size from input image. The statistical projection analysis project the brightness of multilevel thresholding image into horizontal and vertical direction and decide the thresholding value of face. And the algorithm extracted elliptical type block of face from input image in order to reduce the back ground region and hair region efficiently. The proposed algorithm can reduce searching area of feature extraction and processing time for face recognication.

• 자원환경지질
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• 제26권1호
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• pp.1-10
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• 1993

The Andong serpentinite body is distributed along the Andong fault, and shows an elliptical shape. The serpentinite is composed of serpentine minerals and other various minerals such as forsterite, pyroxene, talc, tremolite, chlorite, prehnite, calcite and dolomite. The serpentine minerals consist primarily of lizardite with minor chrysotile. Antigorite rarely occurs in some veins. The serpentinite is largely divided into two alteration zones by the occurrence and mineral assemblages. One of the alteration zones is composed of a large amount of serpentine minerals. The other is characterized by tremolite and chlorite. The alteration zone composed of tremolite and chlorite seems to have been formed by hydrothermal alteration after the formation of serpentinite. It is considered that the serpentinite have been formed by alteration of the ultramafic rock such as peridotite.

• Journal of electromagnetic engineering and science
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• 제14권4호
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• pp.346-348
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• 2014

A dispersion analysis is performed to estimate the stopband characteristics of electromagnetic bandgap (EBG) structures with defected ground structures (DGS) of various shapes. Design guidelines are suggested for both elliptical and rectangular DGS patterns that result in a maximum stopband bandwidth for a given perforation area. This method provides a basis for numerical optimization techniques that can be used in synthesizing DGS shapes to meet bandgap requirements and layout constraints.

• 천문학회지
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• 제36권spc1호
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• pp.117-124
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• 2003

Pre-launch calibration data have been analyzed for evaluating the point spread function (PSF) of Yohkoh Soft X-ray Telescope (SXT). Especially, it is found crucial that the effect of undersampling should be treated properly. The best fit solution of the SXT PSF, which is modeled by an elliptical Moffat function, has been derived by the comparison with the ground experiment data. In order to examine the off-axis variation of the SXT PSF, we need to define in advance the location of the optical axis on the CCD. According to the previous studies, the off-axis variation of effective area (the vignetting function) may be approximated either by two non-concentric cones or by a cone with some flat distortions. There have been, however, no fully approved representations for the SXT vignetting effect. The effect of the shift of the optical axis from the geometrical center of the telescope is investigated by numerical simulation. It is revealed from our study that the full width at half maximum (FWHM) of the SXT PSF stays nearly constant within an error bound over the central area of the CCD where the solar disk is located.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2000년도 추계학술대회 논문집
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• pp.132-135
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• 2000

A process design expert system for rotationally symmetric deep drawing products has been developed The application of the expert system to non-axisymmetric components, however, has not been reported yet. Thus, in this present study, the expert system for non-axisymmetric deep drawing products with elliptical shape was constructed by using process sequence design. The system developed in this work consists of four modules. The first one is a recognition of shape module to recognize non-axisymmetric products. The second one is three dimensional (3-D) modeling module to calculate the surface area for non-axisymmetric products. The third one is a blank design module to create an oval-shaped blank with the identical surface area. The forth one is a process planning module based on the production rules that play the best important role in an expert system for manufacturing. The production rules are generated and upgraded by interviewing with field engineers.

• 한국항만학회지
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• 제6권1호
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• pp.69-91
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• 1992

A new type of horizontal submerged break water or fixed structure to control waves near coastal area is introduced to focus wave energy before or behind it. Intentionally, the water depth near the structure is changed gradually to get a refraction and diffraction effect. The concentration of wave energy due to the structure was analyzed for the selected design of structure. The shape of the submerged structure in consideration is a circular combined with elliptical curve not to cause reflection of waves at the extreme edge of the structure but cause wave scattering. The direction of the structure against the incident wave is changed easily in the model Applying a regular wave train the following were examined. 1) whether a crescent plain submerged structure designed by the wave refraction theory can concentrate wave energy at a focal zone behind and before it without wave breaking phenomenon. 2) Location of maximum wave amplification factor in terms of the incident wave direction, wave period, etc. In any event the study would contribute to control waves near coastal area and to protect a beach from erosion without interruption of ocean view it is an useful study for the concentration of wave energy efficiently with the increase of wave height.

• 대한두개안면성형외과학회지
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• 제14권1호
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• pp.16-23
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• 2013

Background: Even though degrees of deformation of microform cleft lip are not high, it has to be corrected with various procedures upon conditions and areas since it has various expressions. Many studies have focused on the classifications and procedures, but there are only a few studies on how much these procedures are performed in the actual field. This study aims to analyze the utilization of various procedures upon major correction points. Methods: A total of 52 patients who had been corrected by one surgeon from 1995 to 2011 were enrolled as subjects. Based on the medical records, it was checked whether the incision was made or not along with the correction procedures for alar base and philtral column, Cupid's bow, and vermillion free margin. Results: In case of an incision, full incision (42 times) was conducted most frequently. For alar base and philtral column, muscle re-approximation (25 times) was performed most frequently. However, recently, it was shown that excision on only the affected area and correction with dermis were more likely to be used. For Cupid's bow and vermilion free margin, elliptical excision on the only affected area followed by re-approximation was performed most frequently for 46 times (Cupid's bow) and 44 times (vermilion free margin), respectively. Conclusion: For the correction of microform cleft lip, less invasive procedures are preferred. However, in the actual field, if needed, aggressive procedures consisting of incisions have been conducted to correction. These trends are somewhat changed to utilization of a simple procedure, such as excision on the modified area, followed by a re-approximation rather than complicated procedures using the muscle.

• 천문학회지
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• 제38권2호
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• pp.179-182
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• 2005

We conducted an extremely wide field survey of z ${\~}$ 6 Lyman break galaxies (LBGs) to precisely derive their bright end surface density overcoming the bias due to cosmic variance. We selected out LBG candidates in the Subaru/ XMM-Newton Deep Survey Field (SXDS) over the total of ${\~}1.0\;deg^2$ sky area down to $z_{AB} = 26.0 ({\ge}3{\sigma},\;2'.0 aperture)$ using i' - z' > 1.5 color cut. This sample alone is likely to be contaminated by M/L/T dwarfs, low-z elliptical galaxies, and z ${\~}$ 6 quasars. To eliminate these interlopers, we estimated their numbers using an exponential disk star count model, catalogs of old ellipticals in the SXDS and other field, and a z${\~}$6 quasar luminosity function. The finally derived surface density of z ${\~}$ 6 LBGs was 165 $mag^{-1}\;deg^{-2}$ down to $z_{AB}$ = 26.0 and shows good agreement with previous results from the narrower field survey of HST GOODS.