• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.3
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• pp.173-179
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• 2017

This paper analyzes actuator characteristics for main wing and tail surfaces of an ornithopter by using a motion capture test. Experiments with the ornithopter are conducted indoor, and its fuselage is held on a jig to reduce interaction with vibration generated by flapping motion. The motion capture system detects the movement of markers attached on the main wing and tail wing tip. Experimental results show that the main wings tend to change its amplitude according to the flapping frequency, and the lift and thrust generation simulation is implemented by applying the experimental results and the ornithopter specification to Modified Strip Theory. Step input excitation is applied for experimental analysis of the tail wing in horizontal and vertical directions. As a result, horizontal and vertical tail wings have different characteristics in terms of overshoot, final value, damping ratio and natural frequency because they have different wing structures and linkages.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.38 no.6
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• pp.665-674
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• 2001

In this paper, a reduced complexity fillet to simultaneously suppress the blocking and ringing artifacts of compressed video sequence is addressed. A new one dimensional regularized function to incorporate the smoothness to its neighboring pixels into the solution is defined, resulting in very low complexity filter The proposed regularization function consists of two sub-functions that combine local data fidelity and local smoothing constraints. The regularization parameters to control the trade-off between the local fidelity to the data and the smoothness are determined by available overhead information in decoder, such as maroc-block type and quantization step size. In addition, the regularization parameters are designed to have the limited range and stored as look-up-table, and therefore, the computational cost to determine the parameters can be reduced. The experimental results show the capability and efficiency of the proposed algorithm.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.236.2-236.2
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• 2014

세계 반도체 시장은 컴퓨터 기능이 더해진 모바일 기기의 수요가 증가함에 따라 메모리반도체의 시장규모가 최근 빠른 속도로 증가했다. 특히 모바일 기기에서 저장장치 역할을 하는 비휘발성 반도체인 NAND Flash Memory는 스마트폰 및 태블릿PC 등 휴대용 기기의 수요 증가, SSD (Solid State Drive)를 탑재한 PC의 수요 확대, 서버용 SSD시장의 활성화 등으로 연평균 18.9%의 성장을 보이고 있다. 이러한 경제적인 배경 속에서 NAND Flash 미세공정 기술의 마지막 단계로 여겨지는 1Xnm 공정이 개발되었다. 그러나 1Xnm Flash Memory의 생산은 새로운 제조설비 구축과 차세대 공정 기술의 적용으로 제조비용이 상승하는 단점이 있다. 이에 따라 제조공정기술을 미세화하지 않고 기존의 수평적 셀구조에서 수직적 셀구조로 설계 구조를 다양화하는 기술이 대두되고 있는데 이 중 Flash Memory의 대용량화와 수명 향상을 동시에 추구할 수 있는 3D NAND 기술이 주목을 받게 되면서 공정기술의 변화도 함께 대두되고 있다. 3D NAND 기술은 기존라인에서 전환하는데 드는 비용이 크지 않으며, 노광장비의 중요도가 축소되는 반면, 증착(Chemical Vapor Deposition) 및 식각공정(Etching)의 기술적 난이도와 스텝수가 증가한다. 이 중 V-NAND 3D 기술에서 사용하는 박막증착 공정의 경우 산화막과 질화막을 번갈아 증착하여 30layer 이상을 하나의 챔버 내에서 연속으로 증착한다. 다층막 증착 공정이 비정상적으로 진행되었을 경우, V-NAND Flash Memory를 제조하기 위한 후속공정에 영향을 미쳐 웨이퍼를 폐기해야 하는 손실을 초래할 수 있다. 본 연구에서는 V-NAND 다층막 증착공정 중에 다층막의 두께를 가상 계측하는 알고리즘을 개발하고자 하였다. 증착공정이 진행될수록 박막의 두께는 증가하여 커패시터 관점에서 변화가 생겨 RF 신호의 진폭과 위상의 변화가 생긴다는 점을 착안하여 증착 공정 중 PECVD 장비 RF matcher와 heater에서 RF 신호의 진폭과 위상을 실시간으로 측정하여 데이터를 수집하고, 박막의 두께와의 상관성을 분석하였다. 이 연구 결과를 토대로 V-NAND Flash memory 제조 품질향상 및 웨이퍼 손실 최소화를 실현하여 제조 시스템을 효율적으로 운영할 수 있는 효과를 기대할 수 있다.

• The Transactions of the Korea Information Processing Society
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• v.6 no.8
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• pp.2196-2203
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• 1999

This paper describes the bus scheduling problem and register optimization method in datapath synthesis. Scheduling is process of operation allocation to control steps in order to minimize the cost function under the given circumstances. For that purpose, we propose some formulations to minimize the cost function for bus assignment to get an optimal and minimal cost function in hardware allocations. Especially, bus and register minimization technique are fully considered which are the essential topics in hardware allocation. Register scheduling is done after the operation and bus scheduling. Experiments are done with the DFG model of fifth-order digital ware filter to show its effectiveness. Structural integer programming formulations are used to solve the scheduling problems in order to get the optimal scheduling results in the integer linear programming environment.

• Nuclear Engineering and Technology
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• v.27 no.3
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• pp.336-343
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• 1995

The Self Tuning Regulator(STR) method which is an approach of adaptive control theory, is ap-plied to design the fully automatic power controller of the nonlinear reactor model. The adaptive control represent a proper approach to design the suboptimal controller for nonlinear, time-varying stochastic systems. The control system is based on a third­order linear model with unknown, time-varying parameters. The updating of the parameter estimates is achieved by the recursive extended least square method with a variable forgetting factor. Based on the estimated parameters, the output (average coolant temperature) is predicted one-step ahead. And then, a weighted one-step ahead controller is designed so that the difference between the output and the desired output is minimized and the variation of the control rod position is small. Also, an integral action is added in order to remove the steady­state error. A nonlinear M plant model was used to simulate the proposed controller of reactor power which covers a wide operating range. From the simulation result, the performances of this controller for ramp input (increase or decrease) are proved to be successful. However, for step input this controller leaves something to be desired.

• 대한근관절건강학회:학술대회논문집
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• 2002.11a
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• pp.238-246
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• 2002

최근 경제의 발전과 의학의 발달로 인하여 인간의 수명은 점차 연장됨에 따라, 노인인구도 급격히 증가하고 있다. 40세 이상 여성 인구도 8.998천명으로 전체 여성의 38%를 차지하며 이는 매년 증가할 것이다. 그리하여 전체 인구에 대한 폐경 여성의 점유율도 급격히 증가하고 있다. 폐경 이후 $5{\sim}10$년 동안 매년 $2{\sim}4%$씩 골농도가 감소하고 있기 때문에 폐경기 여성을 위협하는 주요 질환 중 하나가 골다공증이다. 하지만 골다공증은 뚜렷한 자각증상이 없어 골 기형 및 골절이 발생하기 전에는 조기발견이 어렵다. 골다공증은 모든 중년 여성의 건강문제이므로 지역사회에서 골절 발생 위험율을 줄일 수 있도록 골다공증 예방을 위한 건강관리가 필요하다. 본 연구의 목적은 지역사회에서 적용할 수 있는 골다공증 예방 프로그램을 개발하여 그 효과를 검정한 후 지역사회 중년 여성 건강증진 프로그램으로 활용코저 함에 있다. 골다공증 예방 프로그램은 운동과 교육으로 구성하였으며, 12주 동안 점핑 동작 위주의 에어로빅과 스텝퍼 운동과 근력강화운동(최대 심박수의 $70%{\sim}80%$, $70{\sim}80$분, 3회/주)을 병행하여 실시하였고, 교육은 운동과 칼슘 섭취의 중요성을 건강 신념 이론에 근거하여 자기 효능감을 증대시키는 교육을 하여 지속적인 운동 실천과 칼슘식이 섭취를 하도록 하였다. 대상자는 서울시 일개 보건소에서 골감소증으로 진단받은 폐경 여성으로 실험군 19명과 대조군 19명이었다. 골다공증 예방 프로그램의 효과는 골밀도, DPD ratio, osteocalcin, 일일 평균 칼슘섭취량, 일일 열량 소모량, 배근력, 최대 산소 섭취량, 제지방량과 건강신념 변수로 측정하였다. 수집된 자료는 PC SPSS 8.0 프로그램을 이용하여 대상자의 일반적 특성은 실수와 백분율로 실험군과 대조군의 동질성 검사는 t-test, $x^2-test$ 및 Fisher exact test를 이용하였고, 두 집단 간 결과변수들의 중재 전후의 차이는 t-test로 분석하였다. 연구 결과는 다음과 같다. 1) $L_{2-4}$ 골밀도는 실험군이 대조군에 비하여 유의하게 높았다. 2) DPD ratio와 osteocalcin은 두 집단간 유의한 차이가 없었다. 3) 배근력은 실험군에서 대조군보다 유의하게 증가하였으나, 제지방량과 최대 산소 섭취량은 유의한 차이가 없었다.

• Journal of the Korean Electrochemical Society
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• v.9 no.2
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• pp.95-99
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• 2006

Electrochemical properties were studied for a single particle of active material of hydrogen storage alloy $(MmNi_{3.55}Co_{0.75}Mn_{0.4}Al_{0.3})$ and nickel hydroxides $(NiOH)_2$ for the secondary Nickel Metal Hydride (Ni-MH) batteries using the microelectrode, which was manipulated to make electrical contact with an active material particle for cyclic voltammograms (CV) and potential-step experiments. As a result of CV test, it was found that three kinds of hydrogen oxidation peaks at -0.9, -0.75 and -0.65 V and hydrogen evolution peak at -0.98 V for hydrogen storage alloy were separately observed and two kinds of peaks of proton oxidation/reduction at 0.45 and 0.32 V and oxygen evolution reaction (OER) at 0.6 V for nickel hydroxides were also more clearly observed. Furthermore hydrogen diffusion coefficient within a single particle was also found to vary the order between $10^{-9}\;and\;10^{-10}cm^2/s$ over the course of hydrogenation and dehydrogenation process for potential-step experiments.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.5514-5521
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• 2013

This study is an experiment to look into recovering process after maximum anaerobic exercise of career wrestlers and their basic fitness. First, group time results in anaerobic power test did not show meaningful differences between groups in PP, MP, LP field. Second, blood glucose showed meaningful difference in 5-year wrestlers group according to time-wise result (p<.001). Third, time-wise results in blood lactic acid concentration showed meaningful difference all in 5-year, 10-year and 15-year career wrestlers group (p<.001). Fourth, side step and general reaction did not show meaningful differences in all the 3 groups. In conclusion, increase or decrease was seen from and also significant differences were seen from the change of anaerobic power, glucose, lactic acid, concentration, basic physical strength reaction which have influence over athletic performance of players after anaerobic exercise. It was found that 5-year career players group was good at variables of power test and glucose. Reason why recovery capability in connection with degree of fatigue was poor in 15-year career players group seemed to have correlation between career and age.

• Journal of the Korean Applied Science and Technology
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• v.37 no.4
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• pp.649-658
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• 2020

The purpose of this study is to verify the difference in health and obesity according to water and coffee intake. The study subject is 900 female college students. Physical fitness factors measured in this study were physical strength(grip strength, back muscle strength), muscle endurance (sit-up), Flexibility(Sit & reach) and cardiopulmonary endurance(harvard step). The factors of body composition (intracellular fluid, extracellular fluid, protein, mineral, body water content, muscle mass, lean body mass, body fat mass) and obesity (BMI, body fat percentage, abdominal fat percentage, obesity) were measured with the Inbody equipment. SPSS program was used for all data analysis. Group differences were verified by two-way ANOVA and one-way ANOVA. The results are as follows. There was no interaction effect between water and coffee intake on health and obesity. Therefore, the difference of the dependent variables according to each independent variable was verified. There was no significant difference in physical fitness according to water intake and coffee intake, but there was a significant difference in body composition (intracellular fluid, protein, minerals, body water, muscle mass and lean body mass). Water drinking group more than 7 cups had significantly higher body composition than the 1-4 cups water drinking group. In the case of coffee, the body composition of the 3 cup intake group was significantly higher than that of the none intake group. Obesity was significantly higher than the none intake and 1-2 cup intake groups. Based on the study results, water intake was not related to obesity, but coffee was related. For further studies, it would be better to consider gender and age differences in drinking various beverages such as water and coffee and that would be used to suggest a desirable way of water intake according to individual characteristics of the better health.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.04a
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• pp.5-9
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• 2004

In this paper, we studied the OCT(Optical Coherence Tomography) system which it has been extensively studied because of having some advantages such as high resolution cross-sectional images, low cost, and small size configuration. A basic principle of OCT system is Michelson interferometer. The characteristics of light source determine the resolution and the transmission depth. As a results, the light source have a commercial SLD with a central wavelength of 1,285 nm and FWHM(Full Width at Half Maximum) of 35.3 nm. The optical delay line part is necessary to equal of the optical path length with scattered light or reflected light from sample. In order to equal the optical path length, the stage which is attached to reference mirror is moved linearly by step motor And the interferometer is configured with the Michelson interferometer using single mod fiber, the scanner can be focused of the sample by using the reference arm. Also, the 2-dimensional cross-sectional images were measured with scanning the transverse direction of the sample by using step motor. After detecting the internal signal of lateral direction at a paint of sample, scanner is moved to obtain the cross-sectional image of 2-demensional by using step motor. Photodiode has been used which has high detection sensitivity, excellent noise characteristic, and dynamic range from 800 nm to 1,700 nm. It is detected mixed small signal between noise and interference signal with high frequency After filtering and amplifying this signal, only envelope curve of interference signal is detected. And then, cross-sectional image is shown through converting this signal into digitalized signal using A／D converter. The resolution of the OCT system is about 30$\mu\textrm{m}$ which corresponds to the theoretical resolution. Also, the cross-sectional image of ping-pong ball is measured. The OCT system is configured with Michelson interferometer which has a low contrast because of reducing the power of feedback interference light. Such a problem is overcomed by using the improved inteferometer. Also, in order to obtain the cross-sectional image within a short time, it is necessary to reduce the measurement time for improving the optical delay line.