• 한국철도학회:학술대회논문집
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• 한국철도학회 1998년도 추계학술대회 논문집
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• pp.530-536
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• 1998

In the design of the light rail transit which is more reliable and economical, it is essential to develope a efficient third rail system. Especially, the analysis for the conductivity of conduct rail and the wear of collecting shoe is the first step of its development. In this paper, experiments for conductivity in conductor rail, wear in collecting shoe were performed respectively as different materials of conductor rail and current collector. Noise level and interruption, wear and contact resistance of collecting shoe were proposed as design parameters for the development of this system. Experimental equipment and methods of design parameter stated above were proposed, which is expected that analyzed results will be used as a basic data for the development of the system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 A
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• pp.455-457
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• 1999

In this paper, the wearing characteristics of current collecting shoes, interruption phenomena and contact resistances between collecting shoes and conductor rails are established as design parameters for development of the third rail current collector. An experimental analysis for established design parameters is performed as the materials of current collector shoe, contact force, sliding velocity and contact condition(dry/wet condition) between current collectors shoe and conductor rails. As a result of this study, the magnitude of contact force is in proportion to the amount of wear in the collecting shoe, but is in inverse proportion to the interruption and contact resistance between the collecting shoe and the conductor rail. And optimal values of design parameters are pre sented through analyzing the experimental results of the amount of wear, interruption and contact resistance.

• 한국운동역학회지
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• 제20권4호
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• pp.479-486
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• 2010

The purpose of this study was to determine the effects of high-heeled shoe on the quiet standing and gait balance. Twenty women (mean height: $161.6{\pm}3.3\;cm$, mean body mass: $53.8{\pm}6.3\;kg$, mean age: $23.8{\pm}2.7$ yrs..) who were without history or complain of lower limb pain took part in this study. They were asked to stand quietly on a force platform for 30 sec and walk on it at their preferred walking speed (mean speed $3.14{\pm}0.5\;km/hr$.) with wearing three different high-heeled shoe, 3, 7, 9 cm high for collecting data. Data were randomly recorded to collect two trials for quiet standing and five trials for walking The parameters to have been analyzed for comparison between three conditions of the height of high-heeled shoe were COP(Center of Pressure) range, COP velocity, sway area, and free moment on the static balance and COP range, COP velocity, and free moment on the dynamic balance. In this study, high-heel height affected on the COP range and velocity in the ante-posterior direction during walking, dynamic balance, but didn't affect on the quiet standing, static balance.

• 한국응용과학기술학회지
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• 제36권3호
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• pp.840-852
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• 2019

스포츠 상품 시장에서 각 브랜드가 소비자에게 미치고자 하는 영향력은 여러 가지 형태로 시도되었으며, 그 효과 또한 증명되어 가고 있다. 각 브랜드들이 자신들이 활용할 가치가 있다고 판단하여 수립한 다양한 마케팅 전략들이 증명되어가고 있는 것이다. 하지만 최근 나타난 새로운 소비 유형이라 할 수 있는 스포츠 상품 수집가를 활용한 마케팅 전략은 지금껏 그 영향력이 실증적으로 검증된 바가 없었다. 기존의 스포츠 상품 시장에서 나타난 수집 행위에 이해도가 매우 낮았기 때문이다. 어느 정도 한계에 봉착했다고 여겨지는 스포츠 상품 시장에 새로운 마케팅 전략이 필요하다고 판단한 도전적 사고에서 본 연구를 시작하였으며 스포츠 상품 수집가를 활용한 마케팅 전략을 수립함에 있어서 그 영향력이 형성되는 경로를 설정하고 증명하는데 그 목적을 두고 있다. 이 연구의 목적을 달성하기 위하여 가상의 스포츠 상품 수집가의 상품 설명에 대한 자극물을 접한 잠재 소비자 231명을 대상으로 SPSS 21.0과 AMOS 20.0을 이용하여 빈도분석, 신뢰도분석, 상관관계분석 및 확인적 요인분석과 구조방정식을 이용하였다. 이 연구에서 도출된 결과를 바탕으로 하여 스포츠 상품 시장에서 스포츠 상품 수집가들이 보유하고 있는 전문성을 바탕으로 하는 새로운 마케팅 전략의 경로를 발견하였다고 할 수 있으며, 이를 바탕으로 침체된 우리나라 스포츠 상품시장에 새로운 성장 동력의 하나로 작용할 수 있기를 기대하는 바이다.

• International Journal of Internet, Broadcasting and Communication
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• 제13권1호
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• pp.90-99
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• 2021

Recently, studies on wearable devices in ubiquitous computing environments have increased and the technology collecting user's activities to provide services has received great attention. We have compared the step counting methods according to sensor molding methods in case of counting steps by using the piezoelectric sensor. We have classified the cases which could result from the course of molding the internal module of a smart shoe as follows: (i) the module is unmolded, (ii) molded but only to the extent that a sensor is fixed or (iii) molded to the extent that a sensor is not moved. Moreover, we have made comparison to verify which algorithm should be used to increase the accuracy of counting steps by the respective cases. Based on the comparison result, we have confirmed that the accuracy of counting steps is higher when using gradient value rather than when using threshold value. In the case of no molding and small molding under the condition of using gradient value, it was turned out to be 100% accuracy for step counting.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.3046-3051
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• 2011

The third-rail system is an important device supplying power directly to the Maglev train through physical contact with the collecting shoe. It is directly related to safety and reliability for the running of Maglev. However, most the third-rail system used in Korea depend on foreign product or technologies, Korea Urban Maglev in the development of appropriate power feeding is urgent. In particular, the turnout section is the weakness point in the system because bending force by turnout section movement and fatigue caused by repetitive motion as well as the expansion by temperature, the forces by Maglev collecting shoe is added th the third-rail. Therefore, this paper proposes the third-rail system appropriate for Korean Urban Maglev of turnout section. To verify the structural stability of POSCO ICT third-rail system, the finite element analysis and physical testing was performed. The third-rail is fixed on each side of the turn-out section steel structure by epoxy insulation supporter and the integral behaviors are occurred. Therefore, the maximum horizontal displacements of each support are investigated and then, it is applied to finite element model of the third-rail to investigate the moments and stress. Also, the bending test about one million times and Expansion Joint for the third-rail was performed. The third-rail system safety and reliability was identified by test line on Korea Institute of Machinery & Materials in Deajeon for under the actual usage environment such as the Maglev and turn-out operation.

• 한국운동역학회지
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• 제27권2호
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• pp.133-140
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• 2017

Objective: The purpose of this study was to determine the relationship between center of pressure (CoP) and local stability of the lower joints, which was calculated based on approximate entropy (ApEn) during walking in elderly women. Method: Eighteen elderly women were recruited (age: $66.4{\pm}1.2yrs$; mass: $55.4{\pm}8.3kg$; height: $1.56{\pm}0.04m$) for this study. Before collecting data, reflective marker triads composed of 3 non-collinear spheres were attached to the lateral surface of the thigh and shank near the mid-segment to measure motion of the thigh and shank segments. To measure foot motion, reflective markers were placed on the shoe at the heel, head of the fifth metatarsal, and lateral malleolus, and were also placed on the right anterior-superior iliac spine, left anterior-superior iliac spine, and sacrum to observe pelvic motion. During treadmill walking, kinematic data were recorded using 6 infrared cameras (Oqus 300, Qualisys, Sweden) with a 100 Hz sampling frequency and kinetic data were collected from a treadmill (Instrumented Treadmill, Bertec, USA) for 20 strides. From kinematic data, 3D angles of the lower extremity's joint were calculated using Cardan technique and then ApEn were computed for their angles to evaluate local stability. Range of CoP was determined from the kinetic data. Pearson product-moment and Spearman rank correlation coefficient were applied to find relationship between CoP and ApEn. The level of significance was determined at p<.05. Results: There was a negative linear correlation between CoP and ApEn of hip joint adduction-abduction motion (p<.05), but ApEn of other joint motion did not affect the CoP. Conclusion: It was conjectured that ApEn, local stability index, for adduction/abduction of the hip joint during walking could be useful as a fall predictor.

• Safety and Health at Work
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• 제14권4호
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• pp.457-466
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• 2023

Background: During hot environment work tasks with whole-body enclosed anti-bioaerosol suit, the combined effect of heavy sweating and exhaled hot humid air may cause the N95 medical respirator to saturate with water/sweat (i.e., water-blocking). Methods: 32 young male subjects with different body mass indexes (BMI) in whole-body protection (N95 medical respirator + one-piece protective suit + head covering + protective face screen + gloves + shoe covers) were asked to simulate waste collecting from each isolated room in a seven-story building at 27-28℃, and the weight, inhalation resistance (R_f), and aerosol penetration of the respirator before worn and after water-blocking were analyzed. Results: All subjects reported water-blocking asphyxia of the N95 respirators within 36-67 min of the task. When water-blocking occurred, the R_f and 10-200 nm total aerosol penetration (P_t) of the respirators reached up to 1270-1810 Pa and 17.3-23.3%, respectively, which were 10 and 8 times of that before wearing. The most penetration particle size of the respirators increased from 49-65 nm before worn to 115-154 nm under water-blocking condition, and the corresponding maximum size-dependent aerosol penetration increased from 2.5-3.5% to 20-27%. With the increase of BMI, the water-blocking occurrence time firstly increased then reduced, while the R_f, P_t, and absorbed water all increased significantly. Conclusions: This study reveals respirator water-blocking and its serious negative impacts on respiratory protection. When performing moderate-to-high-load tasks with whole-body protection in a hot environment, it is recommended that respirator be replaced with a new one at least every hour to avoid water-blocking asphyxia.