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        검색결과 8

        1.
        2019.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES: This study analyzed the differences in drivers’behaviors and car movements between drowsy driving conditions and normal driving. METHODS: This study analyzed behavior data from 32 participants and the related car movement data in a field test under drowsy driving and normal driving conditions. Acquired data were closed-eye time, distance between the test car and the left lane, distance between the test car and the right lane, driving speed, video clip of the driver’s face during driving, and so on. A total of 30 samples for drowsy driving and normal driving were selected once errors had been excluded. RESULTS: There were three factors that differed between drowsy driving and normal driving conditions: closed-eye time, distance between the test car and the left lane, and distance between the test car and the right lane. These results were significant at the 0.05 level. CONCLUSIONS : This study shows that there are three factors that vary significantly between drowsy driving and normal driving conditions that can be useful for detecting drowsy driving. Future studies should be designed with these results in mind, further considering, age, type of road, study site, and so on.
        4,000원
        2.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This study analyzed the difference in a driver’s workload between using a driving simulator and field driving in tunnel, highway.METHODS: Based on the literature review, it was found that a driver’s workload could be quantified using biosignals. This study analyzed the biosignal data of 30 participants using data collected while they were using a driving simulator and during a field test involving tunnel driving. Relative energy parameter was used for biosignal analysis.RESULTS : The driver’s workload was different between the driving simulator and field driving in tunnels, highway. Compared with the driving simulator test, the driver’s workload exhibited high value in field driving. This result was significant at the 0.05 level. The same result was observed before the tunnel entrance section and 200 m after the entrance section.CONCLUSIONS: This study demonstrates the driving simulator effect that drivers feel safer and more comfortable using a driving simulator than during a field test. Future studies should be designed considering the result of this study, age, type of simulator, study site and so on.
        4,000원
        3.
        2010.11 구독 인증기관 무료, 개인회원 유료
        Abstract 1. 서론 2. 연구방법 3. 사고현황 및 특성 3.1 고령운전자의 교차로 교통사고 3.2 신호기 운영방법 및 작동상태에 따른 사고 특성 3.3 차로폭에 따른 사고 특성 4. 결론 5. 참고문헌
        4,000원
        5.
        2002.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, an asymmetric lifting posture prediction model was developed, which was a three-dimensional model with 12 links and 23 degrees of freedom open kinematic chains. Although previous researchers have proposed biomechanical, psychophysical, or physiological measures as cost functions, for solving redundancy, they lack in accuracy in predicting actual lifting postures and most of them are confined to the two-dimensional model. To develop an asymmetric lifting posture prediction model, we used the resolved motion method for accurately simulating the lifting motion in a reasonable time. Furthermore, in solving the redundant problem of the human posture prediction, a moment weighted Joint Range Availability (JRA) was used as a cost function in order to consider dynamic lifting. However, it is known that the moment weighted JRA as a cost function predicted the lower extremity and L5/S1 joint motions better than the upper extremities, while the constant weighted JRA as a cost function predicted the latter better than the former. To compensate for this, we proposed a hybrid moment weighted JRA as a new cost function with moment weighted for only the lower extremity. In order to validate the proposed cost function, the predicted and real lifting postures for various lifting conditions were compared by using the root mean square(RMS) error. This hybrid JRA reduced RMS more than the previous cost functions. Therefore, it is concluded that the cost function of a hybrid moment weighted JRA can be used to predict three-dimensional lifting postures. To compare with the predicted trajectories and the real lifting movements, graphical validations were performed. The results also showed that the hybrid moment weighted cost function model was found to have generated the postures more similar to the real movements.
        4,300원
        6.
        2002.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In order to protect the head, baseball helmet must to have proper strength and to absorb the kinetic energy. The purposes of this study are to validate whether the helmet have the protecting ability or not. We performed three kinds of experiment to know about the this ability. To find out the limit of displacement at 4 points(front, rear, right side, and left side), the static load by magnetic dial gauges were used, and to validate the ability of absorption, drop tests were peformed from 0.5 and 1.0 meter. Futhermore, we calculated natural frequency of the helmets by the principle of Lissajous Diagram and we performed FEM(Finite Element Method) analysis. From the results of these experiments, we found that the displacement of helmet was largest at rear point and it was smallest at left-side point(ear-covered part). The ability of absorption was better at the left-side point than the other points.
        4,000원
        7.
        2008.06 KCI 등재 서비스 종료(열람 제한)
        Prunus sargentii of Rosaceae familiy, has been reported to have radical scavenging activity and anti-inflammatory effect. On these facts, this research was conducted to evaluate pharmaceutical activities of the bark extracts P. sargentii. Free radical scavenging activities of fraction (Fr) -5~10 isolated from P. sargentii was higher than 80% respectively at 10ppm. The superoxide dismutase (SOD)-like activity of Fr-5, 9 were about 97, 84%, respectively at 1,000 ppm. Xanthine oxidase inhibitory effect of Fr-9, 10 were about 75, 78%, respectively at 1,000 ppm. The tyrosinase inhibitory effect related to skin-whitening was 72, 68% in Fr-2, 9 isolated from Prunus sargentii R. at 1,000 ppm. Hyaluronidase inhibition activity related to the anti-inflammation effect was 98% for Fr-8 at 500 ppm. Isolation of the methanol soluble fraction from P. sargentii yielded two major phenol compounds, (-)-epicatechin and taxifolin. The structure of the compound was certainly determined by chemical analyses, as well as NMR and Mass spectroscopy. The present study was carried out in a search for new cosmetic material from the bark from P. sargentii. and, (-)-epicatechin and taxifolin were isolated as active principles. So P. sargentii R. methanolic extracts may be used for the cosmetic material.
        8.
        2006.06 KCI 등재 서비스 종료(열람 제한)
        화장품에 응용 가능한 소재를 발굴하기 위한 목적으로 추출조건에 따른 울금 (Curcuma longa L.)의 항산화 효과 및 미백 효과를 수행한 결과는 다음과 같다. 1. DPPH 라디칼에 대한 소거능은 시료 농도 1,000 μg/ml에서 초임계 추출 시료는 89.0%의 저해율을 나타내어, 3가지 추출법 중 초임계 추출물이 가장 높은 전자공여능을 나타내었다. 2. 울금 추출물의 SOD 유사활성을 측정한 결과 3가지 추출방법 중 초임계 추출물의 경우 시료 농도 500 μg/ml에서 95.0% 가장 높은 SOD 유사활성을 나타내었다. 3. Xanthine oxidase 저해활성을 측정한 결과, 시료 농도 1,000 μg/ml의 초임계 추출물에서 40%의 저해능을 나타내어 물, 에탄올, 1,3-butylene glycol 추출물에 비해 높은 효과를 나타내었다. 4. 울금 추출물의 tyrosinase 저해 활성을 측정한 결과 에탄올 및 초임계 추출물의 경우 1,000 μg/ml의 농도에서 각각 82.0, 89.0%로 높은 tyrosinase 저해 활성을 나타내었다. 이상의 실험 결과를 종합해 볼 때, 울금을 이용한 4가지 추출법 중 초임계추출법이 가장 높은 항산화 효과 및 미백효과를 나타내어 화장품의 소재로서 응용이 가능할 것으로 사료된다.