유산소 운동이 비만유전자(β3-AR gene) 다형성 특성이 다른 비만아동의 체력요인에 미치는 영향

유원희(Yoo Won-Hee),이재구(Lee Jae-Koo) 한국체육과학회 2007 한국체육과학회지 Vol.16 No.3

The purpose of this study is to identify the effects of aerobic exercise as the polymorphism in the β3-AR gene of obese children. For this study, 30 children, who is over 25% BMI and do not regularly exercise, were randomly assigned to 2groups. One group is normal group(Trp64Trp, 23children) and the other one is mutation group(Trp64Arg, 7children). Body composition factors and physical abilities were measured before and after exercise program. Blood was collected from vein about 10㎖ and blood analyses were requested. Paired t-test and one-way repeated measured ANOVA were used as the statistical analysis, and significance was accepted at p<.05. From the statistical analysis results for the body composition, and physical fitness, the following conclusions could be obtained. After aerobic exercise, body compositions of obese children are significantly changed in height (+0.4%), BMI (-1.3%), body fat mass (-2.3%), percent body fat(-2.0%)(p<.05). Physical fitness of obese children are significantly changed in muscular strength (+12.9%), muscular endurance (+23.3%), flexibility(+11.8%)(p<.05). After aerobic exercise, there was significantly changed in hight(+0.4%), BMI (-1.2%), body fat mass (-2.4%), percent body fat(-2.0%), muscular strength (+16.2%), muscular endurance (+16.0%), flexibility (+14.0%), cardiovascular endurance (-3.7%), The difference within groups was only muscular strength. In this study, aerobic exercise was found more effective for the enhancement of body composition, blood lipid, physical fitness The β3-AR in normal group was more different after exercise to compare with gene alteration group so that obese is more influence for gene.

철도 차량 횡진동 HILS를 위한 동적 모델링 및 제어 알고리즘 개발

이재하(Lee, Jae-Ha),곽문규(Kwak, Moon-K.),양동호(Yang, Dong-Ho),유원희(You, Won-Hee) 한국소음진동공학회 2012 한국소음진동공학회 논문집 Vol.22 No.7

This paper is concerned with the dynamic modeling for the hardware-in-the-loop simulation of lateral vibrations of a railway vehicle. The resulting dynamic model is a nine degree-of-freedom model which can describe the lateral, roll and yaw motions of the car body and two bogies. It is assumed that the external disturbances come from wheel motions. In order to test the efficacy of the model, the linear quadratic regulator and the sky-hook control algorithm were designed and applied to the model. The simulation results show that both control algorithms are effective in suppressing the vibrations of railway vehicles.

철도차량 차축의 피로강도 설계방법

이동형(Lee Dong-Hyong),권석진(Kwon Seok-Jin),유원희(You Won-Hee) 한국철도학회 2009 한국철도학회 학술발표대회논문집 Vol.2009 No.11월

Railway axles are one of the most important components in railway vehicle with regard to safety, and it is an important research area to verify safety of fatigue strength of railway axle for minimization of derailment of railway vehicle by failure of axles. The axles are subjected to various loads such as vertical, horizontal and traction load, and these are simultaneously exerted when vehicles are running. Therefore, each country are standardized fatigue design method to verify safety of railway axles. This study is to review the standard of fatigue design method such as Japanese (JIS E 4501) and Europe (EN 13103) standard, and to analyze the characteristics and difference of fatigue design method.

속도변화에 따른 고속철도차량의 진동 및 소음 특성

이준석(Lee Jun-Seok),이시우(Lee Si-Woo),고효인(Koh Hyo-In),유원희(You Won-Hee) 한국철도학회 2007 한국철도학회 학술발표대회논문집 Vol.- No.-

In this paper, the characteristics of noise and vibration of high speed train is analyzed depending on its speed. The speed is a very important parameter because it can affect the interaction between the train and the environment as well as the characteristics of the train itself. To measure its characteristics, we analyzed the signals from microphones and accelerometers which were attached to the passenger car of the high speed train. The signals from each sensor were stored in the recorder, and then analyzed by using the signal processing program. The data from each sensor are analyzed with the spectrogram. From the spectrogram, we found some distinct characteristics of the passenger car. Also, the characteristics of the noise propagation were inferred from the spectrogram.

마이크로파 소결법을 이용한 LTCC 기판 Post 전극 형성에 관한 연구

김용석,이택정,유원희,장병규,박성열,오용수,Kim, Yong-Suk,Lee, Taek-Jung,Yoo, Won-Hee,Chang, Byeung-Gyu,Park, Sung-Yeol,Oh, Yong-Soo 한국마이크로전자및패키징학회 2007 마이크로전자 및 패키징학회지 Vol.14 No.4

This study is focused on the effect of the surface properties for the post electrode, which is used in pad formation consisted of SMT such as IC, passive component, combined with fired LTCC substrate, We carried out the surface microstructure of sintered electrode and the basic reliability evaluations with sample fired by microwave sintering to solve the problems occurred in post electrode by electric sintering. We evaluated surface densification status of post electrode according to various conditions of microwave sintering. In additions, it is obtained strong effect on blister improvement of post electrode because of over-sintering and the insufficient out gas in bum out process. As a result of adhesion strength, we confirmed $44.3N/mm^2$ in microwave sintering and $34.5N/mm^2$ in electric sintering, respectively. This result will be used for the basic reliability test. Finally, microwave sintering seems to be economic in process time with 30 min compared to electric sintering with 10 hr. In terms of Mass production and efficiency, microwave sintering are excepted to be higher than electric sintering. LTCC 기판제작에 있어서 Post 전극형성은 실제 IC 및 수동부품을 탑재하는 Pad 형성 부분으로 전극 표면의 특성에 큰 영향을 미치게 된다. 본 연구에서는 일반적인 전기로를 이용한 post 전극 소성시 발생되는 문제점들 개선하여 마이크로파 소결을 통한 전극 미세 구조의 치밀화 및 이에 따른 신뢰성 기초 평가를 진행하였다. 일반적인 전기로와 마이크로파 소결 조건에 따른 전극과 LTCC 세라믹 상태를 평가하였다. 또한 과소성 및 탈바인더 공정시 Out gas 불충분에 의한 전극 부풀림 현상을 개선할 수 있는 효과를 얻을 수 있었으며 실제 solder ball 형성후 실장형 전극의 고착강도를 측정한 결과 기존 전기로에 비해서 30% 고착강도가 증가 하였다. 또한 소결시간을 기존 전기로 10시간에 비해 30분 정도에서 소결 공정이 이루어지므로 95%정도 시간을 단축시킬 수 있음을 확인하였다. 이는 소성로 설계를 통한 양산성, 효율성에 크게 증대되리라 예상된다.

고속철도KTX(Korea Train Express)의 역구내진입 제동시 브레이크슈 사이의 마찰소음에 관한 연구

배원식(Bae Won-Sik),정인수(Chung In-Soo),이동훈(Lee Dong-Hoon),유원희(Yu Won-Hee) 한국철도학회 2007 한국철도학회 학술발표대회논문집 Vol.- No.-

The noises which occurs from the rolling stock can be divided largely into three classes and they are Rolling noise, Traction noise and Aerodynamic noise. In the event of braking the rolling stock which enter into the station, Brake shoes cause Fraction noise (braking noise) and excessive braking noise makes passengers and operators uncomfortable. This study is to reduce squeal noise and minimize displeasure by measuring the braking noise and defining the major noise sources and noise mechanism,

기존선 구간에서의 탈선안전도 향상 방안 연구

김용원(Yong Won Kim),엄범규(Beom Gyu Eom),유원희(Won Hee Yoo),이희성(Hi Sung Lee) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.6

기존선 속도향상 시에 탈선안전도를 고려한 기존선 구간별 최대 운행가능속도에 대한 실용적인 기준을 제시하여 기존선의 곡선부 및 완화곡선부 통과 시 속도를 향상시켜야 한다. 본 연구에서는 탈선의 위험도가 높은 곡선부 통과하는 열차의 고속향상을 도모하기 위하여 실제 선로조건인 동대구-남성현 상ㆍ하행 구간에서의 곡선부 구간별 통과 시 탈선안전도에 미치는 영향을 살펴보았다. 곡선반경별 주행속도를 실제 선로 조건에서의 기존 속도 대비 5-20% 향상시켜 탈선안전도 해석을 수행하였다. When a railway vehicle passing through curves & transitions, the running speed must improve by proposing the practical about maximum running possibility speed of each section on existing line considering derailment safety. In this paper, when the railway vehicle passing through curves of actual track conditions (Dongdaegoo-Namsunghyun up & down lines), the effect that has influence on the derailment safety is examined to devise the high speed of the vehicle which passing through curves which risk of the derailment is high. The derailment safety analysis is performed that the running speed by curve radius improves 5~20% compared with existing speed under actual track conditions.

심근경색을 가진 환자에서 호흡정지 T2강조 자기공명영상의 유용성: 지연 조영증강 영상과의 비교

최상일,강성권,유원희,임청,조중행,이활,정진욱,박재형,이경원,Choi Sang Il,Kang Sung-Kwon,Ryu Won Hee,Lim Cheong,Choh Joong Haeng,Lee Whal,Jeong Jin-Wook,Park Jae-Hyung,Lee Kyung Won 대한자기공명의과학회 2003 Investigative Magnetic Resonance Imaging Vol.7 No.2

목적 : 심근경색을 가진 환자에서 호흡정지 T2강조 자기공명영상의 유용성을 알아보고자 하였다. 대상 및 방법 : 심근 생존능을 평가하기 위하여 자기공명영상이 시행된 환자에서 지연 조영증강을 보였던 11명의 환자를 대상으로 하였다. 지연 조영증강을 보이는 심근부위와 비교하여 T2강 조영상에서 일치하는 부위를 고신호강도, 동등신호강도, 저신호강도로 나누어 분석하였으며, 정상 심근과 경색 부위의 신호강도 세기 및 통벽성 범위(transmural extent)을 측정하였다. 환자의 임상정보를 토대로 심근경색의 시기와 T2 강조영상과의 상관관계를 분석하였다. 결과 : T2강조영상에서 5명의 환자의 12분절에서 정상심근에 비하여 경색부위에 고신호강도를 보였으며, 6명의 환자의 12분절에서 저신호강도를 보였다. 경색부위의 고신호강도는 정상심근에 비하여 $175{\pm}9\%$ 이었으며, 저신호강도는 $73{\pm}5\%$ 이었다 (p < 0.05). 통벽성 범위(transmural extent)의 평가에 있어, T2강조영상에서 고신호강도 부위는 지연 조영증강을 보인 부위보다 컸으나 $(100\%\;vs.\;49{\pm}17\%)$, 저신호강도 부위는 일치하였다. T2 강조영상에서 고신호강도는 심근경색후 11일 이내에 보였고, 저신호강도는 7개월 이후에 보였다. 결론 : 호흡정지 T2 강조영상은 부종 및 섬유화 반흔 범위의 평가와 함께 심근경색의 시기를 예측하는 데에 있어 유용할 것으로 사료된다. Purpose : To evaluate the usefulness of breath-hold T2-weighted MR imaging in patients with myocardial infarction. Materials and Methods : We investigated 11 patients with myocardial infarction who shown delayed enhancement on MR imaging. Infarcted myocardium on T2-weighted MR imaging was classified as high, iso, and low signal area comparing with normal myocardium. The intensity and transmural extent of infracted myocardium was also analyzed. On the basis of clinical information, the stage of infracted myocardium on T2-weighted MR imaging was assessed. Results : It was observed high signal area in 12 segments of 5 patients, low in 12 segments of 6 patients on T2-weighted MR imaging. The high signal intensity of infarcted myocardium was shown as $175{\pm}9\%$ comparing with that of the normal myocardium, low signal intensity as $73{\pm}5\%\;(p\;<\;0.05)$. In the evaluation of transmural extent, the high signal areas on T2-weighted MR imaging were larger than infarct area on delayed enhancement imaging $(100\%\;vs.49\%{\pm}17\%)$, whereas low signal areas on T2-weighted MR imaging correlated. High signal area was visualized on T2-weighted MR imaging within 11 days, whereas low-signal area was seen after 7 months. Conclusion : Breath-hold T2-weighted MR imaging is useful in the evaluation of stage as well as edema and fibrous scar in patients with myocardial infarction.

캡슐트레인 주행 동특성 분석을 위한 축소 시험장치의 개발

이진호(Jin-Ho Lee),유원희(Won-Hee You),이관섭(Kwansup Lee) 한국산학기술학회 2020 한국산학기술학회논문지 Vol.21 No.9

공기 저항이 적은 아진공 상태의 튜브 안을 주행함으로써 초고속주행이 가능한 캡슐트레인은 부상 공극이 커서 인프라 건설 비용 절감에 유리한 초전도 유도 반발식 부상을 채택하고 있다. 초전도 유도 반발식 부상은 부상 공극을 크게 할 수 있고, 별도의 공극 제어가 필요 없는 장점이 있는 반면, 공극 변동량이 크고 부상력에 댐핑 특성이 작기 때문에 차량의 주행 안정성 및 승차감이 악화 될 수 있다. 이러한 단점을 극복하기 위해서는 차량의 주행 동특성에 기반한 주행안정화장치를 설계하고 적용하여야 한다. 본 연구에서는 캡슐트레인의 동특성을 모사하고 주행안정화장치의 성능을 사전에 검토할 수 있는 1/10 스케일의 축소형 시험장치를 개발하였다. 시험장치는 대차의 모션을 구현할 수 있는 6 자유도 스튜어트 플랫폼, 주행안정화장치가 적용된 2차 현가장치 및 차체로 구성되어 있다. Jaschinski가 제안한 동특성 상사 법칙에 따라 축소 시험장치를 제작하였고, 가이드웨이 불규칙도와 부상 강성이 반영된 대차 모션 구현 알고리즘을 적용하였다. 제작된 시험장치를 이용한 실험을 통해 얻어진 결과와 수치해석 결과와의 비교를 통해 시험장치의 성능을 검토하였다. A capsule train runs inside a sub-vacuum tube and can reach very high speed due to the low air resistance. A capsule train uses a superconducting electrodynamic suspension (SC-EDS) method for levitation, which allows for a large levitation gap and does not require gap control. However, SC-EDS has inherent characteristics such as the large gap variation and a small damping effect in the levitation force, which can degrade the running stability and ride comfort. To overcome this, a stability improvement device should be designed and applied based on dynamic analysis. In this study, a 1/10 small-scale testbed was developed to replicate the dynamic characteristics of a capsule train and investigate the performance of stability improvement devices. The testbed is composed of a 6-degree-of-freedom Stewart platform for the realization of bogie motion, a secondary suspension with a running stabilization device, and a carbody. Based on the dynamic similarity law proposed by Jaschinski, the small-scale testbed was manufactured, and a bogie motion algorithm was applied with the consideration of guideway irregularity and levitation stiffness. The experimental results from the testbed were compared with simulation results to investigate the performance of the testbed.

프레팅 마모를 고려한 압입축의 피로균열 발생수명 예측

이동형(Dong-Hyong Lee),권석진(Seok-Jin Kwon),유원희(Won-Hee You),최재붕(Jae-Boong Choi),김영진(Young-Jin Kim) 대한기계학회 2009 大韓機械學會論文集A Vol.33 No.10

In this paper, the procedure to estimate fatigue crack initiation life has been established by considering fretting wear and multiaxial stress states on the contact surface of press-fitted shafts. And a method to calculate the local friction coefficient during the running-in period of fretting wear process has been proposed. The predicted result of worn surface profile in the press-fitted shaft with non-linear local friction coefficient can avoid excessive wear depth estimation compared with that for the case of constant local friction coefficient. Furthermore, the predicted fatigue crack initiation lives based on Smith-Watson-Topper model considering the fretting wear are in good agreement with the experimental data. Consequently, the present method is valid not only for predicting worn surface profile, but also for assessing fatigue crack initiation lives considering the fretting wear during the running-in period in press fits.