• Clinical and Experimental Reproductive Medicine
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• 제13권2호
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• pp.145-151
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• 1986

The purpose of this study is to investigate the cytogenetic characteristics of Down's syndrome in Korea. For this study, selected were 92 patients who were diagnosed as Down's syndrome by the chromosomal analyses, among 115 patients who were supected of Down's syndrome and referred to the Cytogenetic Laboratory, Institute of Reproductive Medicine and Population, Seoul National University, for 2 years from January 1984 to December 1985. Among 92 patients with Down's syndrome 83 (90.2%) had G-trisomy, 4 (4.3%) had translocation, and 2 (2.2%) had mosaicism of normal and G-trisomic cell lines. Two patients of the remaining 3 had both G-trisomic and translocation, 47, XX, t (1:21) (p32:q22), +21, 47, XX, t (9:11) (q34:q14), +21. The remaining 1 patient had 47, XY, +mar.

• 물과 미래
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• 제27권2호
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• pp.121-128
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• 1994

단락부에서의 모형실험을 통하여 표면 유속의 감소경향, 낙하리영역의 길이, 잠재핵(potential core)의 길이 등을 고찰하여 단구 전면에 대한 흐름을 규명하였다. 흐름속에 부류사가 혼재되어 있는 경우, 부유사가 낙하리영역 중에 퇴적하게 되어 단구의 진행 속도에 영향을 주게되므로 이를 규명하기 위하여 단락부에 있어서 부류사의 유입에 대한 실험을 실시하고, 이에 대한 식을 유도하여 실험 결과로부터 이들 식의 유효성을 증명하였다. 또한 단락부의 낙하리영역에서 사이폰에 의하여 채취되는 부류사량에 대한 실험 결과,$q_{s0}$ 를 규정하는 파라메타에 관한 검토를 실시하여 부류사의 퇴적 특성을 설명하였다.

• 한국지능시스템학회논문지
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• 제16권6호
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• pp.671-676
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• 2006

일반적으로 가상 스피커 구현을 위한 음상정위 방법으로 HRTF(Head Related Transfer Function) DB를 원음에 convolution하는 기법을 사용하게 된다. 그러나 비개인화된 HRTF는 가상 스피커 구현에 있어 사용자에 따라 상/하 또는 앞/뒤 방향에 대해서 혼돈을 가져올 수 있어 정위감을 저하시킬 수 있다. 본 논문에서는 상/하, 앞/뒤 정위감을 개선하기 위해 가상 스피커 주변의 HRTF를 그룹화하여 만들어진 새로운 HRTF를 사용한 가상 스피커에 대하여 연구한다. 효과적인 HRTF 그룹화를 위해 필요한 HRTF 개수, 위치 등을 실험을 통해 결정하며, 청감 평가를 수행한다. 생성된 HRTF를 사용한 가상 스피커의 성능 평가 결과, 상/하, 앞/뒤 정위감이 개선됨을 실험을 통해 확인하였다.

• 한국콘텐츠학회논문지
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• 제19권9호
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• pp.122-134
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• 2019

이 연구는 한국 전통춤의 특성을 개념화하고 승무, 살풀이춤, 태평무 전수교육 경험과정에서 나타난 인식을 탐색하고 범주화하는 것이다. 연구 참여자는 20년 이상 한국 춤 경력과 3년 이상 전통춤 이수자 각 2인씩 총6인을 선정하여 전수교육에서 경험한 전통춤 특성과 교육과정에 나타난 체험인식을 중심으로 연계하였다. 심층면담 및 집단토론 내용을 토대로 귀납적 영역분석을 시도하였으며, 분석의 핵심은 구성주의와 경험이론을 토대로 전통춤의 본질과 특성, 전수교육의 상호작용과 경험인식, 레퍼토리별 전승의 교육적 토대와 비전을 분석틀로 하였다. 연구결과, 첫째, 레퍼토리별 이수자들이 공감하는 한국 전통춤의 특성은 신명체험과 즉흥성, 최상의 절제미와 최고의 표현미로 나타났다. 둘째, 전수교육의 경험인식은 (1)과정중심의 상호소통 (2)전승을 위한 새로운 교육체계 (3)공감을 위한 사회적 담론형성이다. 결론적으로 기능전수라는 전통춤 전수교육의 체험과 전승을 위한 새로운 비전은 상호소통과 경험인식의 합리성에 공감하고, 연구결과는 전통춤 전수교육의 유용성과 창의적 요인들로 구분되어 교육적 측면과 연계하여 논의되었다.

• 대한의용생체공학회:의공학회지
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• 제4권1호
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• pp.29-36
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• 1983

In this paper, center frequency down slift of ultrasonic echo signals which for the measurements of frequency dependent attenuation in the biological tissue are estimated. Center frequency down shift of echo-signals are estimated after signal spectrum analysis of whole echo-signals. In case of signal spectrums are simple, estimation of down shift frequency is very simple and in case of complicate spectrum, estimation of down shift frequency is depend on spectral shape. In case of unable to estimate, frequency dependence of medium is nonlinear(n) 1), in which upper shift of spectrums are presented. In case of unable to estimate, spectrum analysis are performed at local position. At consquence, we know that spectral dispersions are caused complicately by biological tissue layer.

• Transactions on Electrical and Electronic Materials
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• 제13권6호
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• pp.292-296
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• 2012

An optimum heat sink for a 30 W chip on board (COB) LED down-light is designed, fabricated, and characterized. By using the SolidWorks Flow simulator and thermal analysis software, the thermal characteristics of the optimum heat sink is analyzed. Four different types of heat sink are simulated and an optimum structure of the heat sink is found. The simulated temperature of the heat sink when operating the LED down-light is $55.9^{\circ}C$, which is only a difference of $2^{\circ}C$ from the measured temperature. In order to reduce the temperature further, a copper spreader is introduced to the heat sink. The temperature of the heat sink with the copper spreader is $3^{\circ}C$ lower than without the copper spreader.

• 조명전기설비학회논문지
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• 제25권9호
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• pp.94-99
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• 2011

This paper verified the characteristics of electrical continuity and mechanical strength of steelwork required to use it as a down-conductor in lightning protection system. It was proven that the steelwork in reinforced concrete apartment has an excellent electrical continuity with low resistance(less than 0.2[${\Omega}$].). But it was confirmed that a poor connection between two reinforcement bars can easily cause serious damages of the concrete even with the impulsive current of 50[kA], 10/350[${\mu}s$]. These results of experiments mean that the additional measures are necessary in using the steelwork as the down-conductor of the lightning protection system.

• 정보저장시스템학회논문집
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• 제7권2호
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• pp.65-69
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• 2011

Head Disk Interface (HDI) in a Hard Disk Drive (HDD) has decreased to achieve high areal density. Thus, the contact between a slider and a disk becomes more important. The contact between the slider and the disk can cause severe wear and damage of both the slider and the disk. Especially, Touch Down (TD) that the contact occurs continuously and repeatedly is extremely dangerous. Therefore, it is necessary to analyze the unstable bouncing vibration of the slider in head-disk interface. In this paper, we investigate the characteristic and causes of the Touch Down.

• 드라이브 ㆍ 컨트롤
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• 제14권3호
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• pp.32-39
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• 2017

In this study, a mathematical model of the pneumatic part in a gas blow-down system is proposed. The mathematical model consists of four major parts: pressure vessel, reservoir, pressure regulator and pipe-line. To ensure accuracy in long-time simulations, heat transfer between gas and pressure vessel is considered. The model is validated by comparing simulation results with experimental data. Experiments are conducted on the ground, where free convection can be assumed. Simulation results indicate the proposed model can accurately describe behavior of a gas blow-down system. Therefore, it may be used for design and analysis of similar systems with a slight modification.

• Nuclear Engineering and Technology
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• 제50권6호
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• pp.854-859
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• 2018

Calculating minimal cut sets is a typical quantification method used to evaluate the top event probability for a fault tree. If minimal cut sets cannot be calculated or if the accuracy of the quantification result is in doubt, the Monte Carlo method can provide an alternative for fault tree quantification. The Monte Carlo method for fault tree quantification tends to take a long time because it repeats the calculation for a large number of samples. Herein, proposal is made to improve the quantification algorithm of a fault tree with circular logic. We developed a top-down iteration algorithm that combines the characteristics of the top-down approach and the iteration approach, thereby reducing the computation time of the Monte Carlo method.