• Proceedings of the Korean Information Science Society Conference
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• 2007.10b
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• pp.202-205
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• 2007

본 논문에서는 3D 점집합으로부터 3D 메쉬를 생성하는 효율적인 기법을 소개한다. 대표적인 3D 삼각화 방법으로 3D Delaunay 삼각화 기법이 있으나 물체의 표면만을 고려한 메쉬 생성을 위한 방법으로 비효율적인 측면이 있다. 본 논문에서는 적은 계산량으로 물체의 표면 메쉬를 생성하는 기법을 소개한다. 물체의 각 영역을 분할하고 각 영역에 대해서 2D Delaunay 삼각화를 적용하여 3D 메쉬 구조를 얻는다. 3차원 점 집합에 대해 OBB를 계산하고 이를 기준으로 점집합을 다양한 각도에서 자르고 각 부분 점집합에 대해서 2D Delaunay 삼각화를 실시한다. 절단하는 각도의 간격이나 폭은 원래의 3D 점집합에서의 가장 가까운 이웃점들까지의 평균 거리를 이용하여 결정하도록 하였다. 후처리 과정으로 삼각 분할과정에서 잘못된 에지의 연결을 제거함으로써 객체의 삼각 분할 결과를 향상시킨다. 제안된 메쉬 생성 기법은 다양한 영상 기반 모델링 응용에서 효과적으로 적용될 수 있다.

• Parasites, Hosts and Diseases
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• v.31 no.2
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• pp.135-140
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• 1993

An experimental study was performed to observe the infectivlty of sparganum (plerocercold of Spirometra erinncel) treated by prazlquantel, gamma-irradiation and mechanical cutting. The spargana were obtained from the naturally Infected European grass snake, Rhabdophis tigrina, or from the expenmentally infected mice. A total of 83 mice (ICR straine were divided Into 3 experimental groups by the source of the damage, fed each UH 5 spargana, and sacnaced 1 month later for worm recovery. In the praziquantel group, the worms were incubated In the concentration of 10㎍/ml (control: Tyrode for 4 hours) for 0.5. 1.2 and 4 hours at 36℃. and fed to mice. The recovery rate from mice in prazlquantel group was not different from that (80%) of control poop and in the range of 76-100%. In the gamma-Irradiation group, the worms were irradiated by 10-1000 Gy with Csl37. The average recovery rates of 69-100% were not different from that of control up to 100 Gy. The rate was 56% under 150 Gy, and 5% by 1000 Gy. In the mechanical cutting group, the worms were cut at 0.5, 1, 2 and 3 m from the anterior end of the scolex. The average recovery rates In each group were 70-90% and that of control was 90%. The present folding suggests that the sparganum be highly resistant to prazlquantel, gamma- irradiation and mechanical cutting. The vitality center of the sparganum must be at the anterior end of Its scolex.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1440-1443
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• 2004

Shearing including punching, blanking, trimming, slitting, etc is one of the most frequently used processes in sheet metal manufacturing. It has been widely used for manufacturing autobody, electronic components, aircraftbody, etc. In this paper, it has been researched by the experiment to examine the effect of burr height corresponding to die clearance, cutting angle, tool sharpness, etc. This paper presents the experimental results with using Al alloy sheet.

• 전기의세계
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• v.13 no.1
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• pp.30-33
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• 1964

최근 우리나라의 isotope사용은 의학 및 농학을 비롯하여 여러 분야에서 활발히 움직이고 있으나 공업면의 응용에는 아직 거의 없는 실정에 놓여있는 것이다. 그것은 계측기의 성능이 종래의 다른 방식과 비교할 때 대단히 우수하여 계측만으로의 목적으로는 좋은 평가를 받았든 것이나 process공업의 목적으로는 측정 절단 그리고 제어를 하는 복잡한 체계로서 시작하여야 되는 고로 다소 고도의 기술을 요하는 난점이 있었기 때문이었다. 따라서 본지에서는 실제 isotope가 process공업에 응용될때 문제되는 점 즉 process제어 정밀도의 우려를 가려내는 검출단의 성능과 각 공업에서 사용할 수 있는 계측기의 제어계를 간단히 해설하여 보기로 한다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.311-311
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• 2004

1960년 레이저가 발명된 이래 레이저의 응용연구가 많은 비중을 차지하여 오늘날 다양한 방면에서 레이저가 필수적인 장치로 각광을 받게 되었다. 레이저의 특성들 중에서 특히 직진성, 에너지 집중도 및 고휘도성을 이용하여 용접, 절단, 각인 등의 산업적 응용에 많이 활용되고 있다 그 중 레이저가 보통의 빛과 같이 투명한 물체를 통과하고 특수한 렌즈를 이용하면 투명한 물체의 내부에 초점을 맞춰 크랙(crack)을 낼 수 있는 바 이를 이용하여 크리스탈이나 유리의 내부에 2차원 형상이나 3차원 형상을 각인시킬 수 있다.(중략)

• Proceedings of the Korea Multimedia Society Conference
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• 2002.05c
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• pp.145-148
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• 2002

본 논문에서는 관상동맥 질환의 객관적 분석을 위해, 혈관단면영상에서의 ROI(Lumen, Media, Plaque)에 대한 정확한 분할과 분할한 영역에서 질병을 유발시키는 요소들에 대한 정량적 분석을 위한 소프트웨어를 개발하였다. 본 시스템은 Visual C++ 6.0을 이용하여 개발하였으며, 현미경으로부터 획득한 관상동맥 단면영상에 적용하여 Lumen, Media와 Plaque를 분할하고, 각 영역의 형태학적 특징을 추출하여 분석 결과를 파일로 저장할 수 있도록 구현하였다. 분석된 결과는 심장질환의 객관적 진단을 위한 보조판단근거로써 사용될 것으로 기대한다.

• Applied Biological Chemistry
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• v.17 no.1
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• pp.42-48
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• 1974

Hot air thin layer drying method was studied for red pepper, Capsicum annum var. longum as the whole and cut pod states, at various temperature and air velocities. Drying curve of whole pod showed a settling down period followed by the first and second falling rate periods. By lowering the drying temperature, the first falling rate period approached to a constant rate one. Cut drying curve had simple falling rate period and also cut drying method could effectively shorten the drying time. Drying rate constant, k, was varied with time for both the drying methods and the plots of k vs. time in two methods sugested the different drying mechanisms. When an average k was taken as a constant value, the following equations; $M-M_e/M_o-M_e=e^{-0.118t}$ and $M-M_e/M_o-M_e=e(-0.342t^{0.128})$ were applicable for whole and cut drying, respectively.

• Journal of the Korean Society for Nondestructive Testing
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• v.33 no.5
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• pp.430-435
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• 2013

This study is investigation of the characteristics for acoustic emission signal generated by destruction on glass fiber bundles and specimen that was machined composite materials surrounding the outside of GFRP cylinder. The Amplitude of acoustic emission signal gets bigger as the cutting angle of knife increases. Accordingly, the number of hits in destruction of composite materials specimen have more in longitudinal direction (longitudinal direction to the glass fiber) than in hoop direction (horizontal direction to the glass fiber) while the amplitude of signals were bigger in hoop direction than longitudinal direction. It was found out that the amplitude of the glass fiber breakage is more than 40 dB and that the amplitude of signal for matrix crack was less than 40 dB because matrix crack signal was not observed when threshold value is 40 dB and matrix crack signal suddenly appered when threshold value is 32 dB. The slope of the amplitude is related to the acoustic emission source and the slope of the amplitude of the horizontal and vertical directions are 0.16 and 0.08. In particular, The slope of the amplitude of longitudinal direction breakage appear similar to the glass fiber breakage and therefore Acoustic emission source of longitudinal direction breakage is estimated the glass fiber breakage.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.3
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• pp.270-280
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• 2016

This paper investigates the evolution of EM admittance of piezoelectric transducers mounted on a notched beam from wave propagation perspective. A finite element analysis is adopted to obtain numerical solutions for Lamb waves reverberating on the notched beam. The mode-converted Lamb wave signals due to a notch are extracted by using the polarization characteristics of piezoelectric transducers collocated on the beam. Then, a series of temporal spectrums are computed to demonstrate the evolution of EM admittance through fast Fourier transform of the mode-converted Lamb wave signals which are consecutively truncated in the time domain. When truncation time is relatively small, the corresponding temporal spectrum is governed by the characteristics of the input driving frequency. As truncation time becomes large, however, the modal characteristics of the notched beam play a crucial role in the temporal spectrum within the input driving frequency band. This implies that mode-converted Lamb waves reverberating on the beam contributes to the resonance of the beam. The root mean square values are computed for the temporal spectrums in the vicinity of each resonance frequency. The root mean square values increase monotonically with respect to truncation time for any resonance frequencies. Finally the implications of the numerical observation are discussed in the context of damage detection of a beam.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.7
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• pp.707-712
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• 2015

During the welding process, welding distortion is caused by the non-uniformity of the temperature distribution in the weldment. Welding distortion is redistributed because the residual stress and rigidity change according to the removal of the welded structure. In shipbuilding in particular, this phenomenon may be observed during the cutting process of lugs that are attached to blocks for transfer. The redistribution of welding distortion also causes problems, such as damage to the cutting tool. The aim of this study is to experimentally analyze the redistribution of welding distortion because of the partial removal of the welded structure. In the experiments conducted in this study, fillet welding and cutting were performed, and longitudinal bending and angular distortion in the welded structures were then investigated and analyzed.