• 제목/요약/키워드: FORCE

검색결과 28,406건 처리시간 0.046초

The Effects of Age, Gender, and Target Force Level on Controlled Force Exertion Tasks

  • Kong, Yong-Ku;Lee, Sung Yong;Kim, Dae-Min;Choi, Kyeong-Hee
    • 대한인간공학회지
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    • 제36권1호
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    • pp.53-67
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    • 2017
  • Objective: The purpose of this study is to build basic data to systematically develop a hand function evaluation tool by determining the effects of age, gender and target force level on the difference in hand function according to the target force level. Background: Precise and objective evaluation of hand functionality is a very important factor in quantifying treatment progress in patients or elderly people, and in verifying treatment effects. However, most hand function evaluations lack objectivity and accuracy, and therefore it is difficult to properly treat patients according to the given situation. Method: Sixteen healthy subjects (eight elderly and eight young people) participated in this study to evaluate the effects of age, gender, and target force level on tracking performance through rRMSE in terms of the tracking force and actual exerted force, by carrying out a task of maintaining six different target force levels for 20 seconds. Results: The result of this experiment indicated that elderly people and women had a lower ability to maintain a certain level of force than young people and men by 16% and 10%, respectively. The target force level results showed that the tracking error of the lowest force level (5% MVC) was significantly higher than that of 15% MVC, which in turn showed a higher tracking error than that of the higher target force levels. Conclusion: The results of this study can thus be utilized to develop a rehabilitation program for elderly people or other patients. Application: The authors expect that the results of the present study will be valuable to develop a rehabilitation program and hand function evaluation tool.

부정교합 진단을 위한 교합력 분석 소프트웨어의 설계 및 구현 : A Pilot Study (Design and Implementation of Occlusion Force Analysis Software for Malocclusion Diagnosis : A Pilot Study)

  • 박경종;김태윤;최흥국
    • 한국멀티미디어학회논문지
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    • 제12권1호
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    • pp.147-155
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    • 2009
  • 교합력 측정과 분석은 힘의 관계를 분석하여 치아의 역학적 관계를 진단하는 방법이다. 본 연구에서는 새로운 교합력 측정 및 분석 시스템 개발의 기초 연구로써 측정 소프트웨어를 설계 및 구현하고 유용성을 평가한다. 이를 위해 교합력의 정상, 비정상을 효과적으로 측정할 수 있는 다양한 도구들을 개발하였다. 첫째, 치아에 작용하는 힘의 중심 변화를 나타내는 표지의 경로와 14개로 나뉜 치아 영역별 교합력 분포를 정량적인 수치와 함께 가시화 하였으며, 둘째, 교합력이 어느 치아의 특정한 영역으로 치우쳐서 작용하는가를 판단할 수 있도록 하기 위해 좌 우 치아 영역의 힘의 균형을 비율로 측정할 수 있는 도구를 구현하였다. 또한 0.5초 단위로 측정된 교합력의 변화를 소프트웨어 상에서 기록할 수 있도록 하였다. 센서 시트 방식의 측정 하드웨어와 연동하여 테스트한 결과, 힘의 분포와 균형을 효과적으로 확인할 수 있었다.

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Experimental study on the method of estimating the vertical design wave force acting on a submerged dual horizontal plate

  • Kweon, Hyuck-Min;Oh, Sang-Ho;Choi, Young-Hwan
    • International Journal of Naval Architecture and Ocean Engineering
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    • 제5권4호
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    • pp.569-579
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    • 2013
  • A steel-type breakwater that uses a submerged dual horizontal porous plate was originally proposed by Kweon et al. (2005), and its hydrodynamic characteristics and design methodology were investigated in a series of subsequent researches. In particular, Kweon et al. (2011) proposed a method of estimating the vertical uplift force that acts on the horizontal plate, applicable to the design of the pile uplift drag force. However, the difference between the method proposed by Kweon et al. (2011), and the wave force measured at a different time without a phase difference, have not yet been clearly analyzed. In this study, such difference according to the method of estimating the wave force was analyzed, by measuring the wave pressure acting on a breakwater model. The hydraulic model test was conducted in a two-dimensional wave flume of 60.0 m length, 1.5 m height and 1.0 m width. The steepness range of the selected waves is 0.01~0.03, with regular and random signals. 20 pressure gauges were used for the measurement. The analysis results showed that the wave force estimate in the method of Kweon et al. (2011) was smaller than the wave force calculated from the maximum pressure at individual points, under a random wave action. Meanwhile, the method of Goda (1974) that was applied to the horizontal plate produced a smaller wave force, than the method of Kweon et al. (2011). The method of Kweon (2011) was already verified in the real sea test of Kweon et al. (2012), where the safety factor of the pile uplift force was found to be greater than 2.0. Based on these results, it was concluded that the method of estimating the wave force by Kweon et al. (2011) can be satisfactorily used for estimating the uplift force of a pile.

공군 병영도서관 운영 현황과 활성화 방안 (The Study on Operating Status and Activation of Air Force Libraries)

  • 성은정;홍재현
    • 한국비블리아학회지
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    • 제26권1호
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    • pp.77-100
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    • 2015
  • 공군 병영도서관은 공군이라는 특수 계층을 대상으로 도서관의 기능을 수행하고 있지만, 그 발전은 시작단계여서 그 시설 및 서비스 등은 기대에 미치지 못하고 있다. 현재까지 공군 병영도서관 전체를 대상으로 한 운영 현황분석은 시도된 바 없다. 이점에 착안하여 본 연구는 공군 병영도서관 전체의 운영 현황 및 활성화 방안에 관한 인식 평가를 단급, 전대급, 대대급으로 구분하여 실증 분석하였다. 총 45개 문항으로 구성한 설문지를 2014년 8월 현재 등록된 총 101개 공군 병영도서관에 배포하였다. 그 중 81개관으로부터 회신을 받았지만, 4개관의 응답은 부실하여 이를 제외한 총 77개관의 응답을 분석하였다. 분석 결과, 본 논문은 공군 병영도서관의 운영 현황과 활성화 방안에 관한 인식을 총체적으로 파악하였고, 공군 병영도서관의 운영상의 문제점을 지적하였다. 나아가 본 논문은 공군 병영도서관 발전을 위한 운영 활성화 방안을 구체적으로 제시하였다.

정면밀링 가공 중 절삭력과 순간 절삭력 성분비를 이용한 반경방향 절입비의 실시간 추정 (On-line Estimation of Radial Immersion Ratio Using Cutting Force and Instantaneous Cutting Force Ratio in Face Milling)

  • 김명곤;권원태
    • 대한기계학회논문집A
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    • 제24권8호
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    • pp.2123-2130
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    • 2000
  • Radial immersion ratio is an important factor to determine the threshold in face milling and should be estimated in process for automatic force regulation. In this paper, presented is a method of on-line estimation of the radial immersion ratio using cutting force. When a tooth finishes sweeping, sudden drop of cutting forces occurs. This force drop is equal to the cutting force that acts on a single tooth at the swept angle of cut and can be obtained from cutting force signal in feed and cross-feed direction. The ratio of cutting forces in feed and cross-feed directions acting on the single tooth at the swept angle of cut is a function of the swept angle of cut and the ratio of radial to tangential cutting force. In the research, it is found that the ratio of radial to tangential cutting force is not affected by cutting conditions and axial rake angle. Therefore, the ratio of radial to tangential cutting force determined by just one preliminary experiment can be used regardless of the cutting conditions. Using the measured cutting force and predetermined ratio, the radial immersion ratio is estimated. Various experiments show that the radial immersion ratio and instantaneous ratio of the radial to tangential direction cutting force can be estimated very well by the proposed method.

아치형 단동하우스의 풍력계수 분포에 관한 연구 (Distribution of Wind Force Coefficients on the Single-span Arched House)

  • 이석건;이현우
    • 생물환경조절학회지
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    • 제1권1호
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    • pp.28-36
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    • 1992
  • The wind pressure distributions were analyzed to provide fundamental criteria for the structural design on e single-span arched house according to the wind directions through the wind tunnel experiment. In order to investigate the wind force distributions, the variation of the wind force coefficients, the mean wind force coefficients, the drag force coefficients and the lift force coefficients were estimated by using the experimental data. The results obtained are as follows: 1. When the wind direction was normal to the wall, the maximum positive wind pressure along the height of the wall occurred approximately at two-thirds of the wall height because of the effects of boundary layer flow. 2. When the wind direction was 30$^{\circ}$ to the wall, the maximum positive wind force occurred at the windward edge of the wall. When the wind direction was parallel to the wall, the maximum negative wind force occurred at the windward edge of the wall. 3. The maximum negative wind force along the width of the roof appeared around the width ratio, 0.4, and that along the length of the roof appeared around the length ratio, 0.5. 4. According to the results of the mean wind force coefficients analysis, the maximum negative wind force occurred on the roof at the wind direction of 30$^{\circ}$. 5. The wind forces at the wind direction of 30$^{\circ}$ instead of 0$^{\circ}$ are recommended in the structural design of supports for a house. 6. To prevent partial damage of a house structure by wind forces, the local wind forces should be considered to the structural design of a house.

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운행 자동차에 대한 정적 및 동적 제동력 검사 시스템의 제동력 특성 비교 (Comparison in Braking Force Characteristics for the Static and Dynamic Braking Force Inspection System about Vehicles in Service)

  • 오상엽
    • 한국자동차공학회논문집
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    • 제23권3호
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    • pp.344-351
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    • 2015
  • Braking force inspection of vehicles in service is certainly one of the most important characteristics that affect vehicle safety. Up to now, in domestic country, the regular safety inspection of vehicles in service has been tested with a roller type brake test (a static braking force inspection system). But, in EU and USA etc. in recent years, it has been tested with a plate type brake test (a dynamic braking force inspection system). In this study, to compare the characteristics of above two test systems, the correlations for the results of braking force are evaluated statistically. As the results, in the case of main braking force, the range of the $R^2$ of the deviation for the left and right side is 0.5386 ~ 0.6231 in the rear axle and 0.0032 ~ 0.0052 in the front axle respectively, then the $R^2$ in the front axle is lower than that in the rear axle and the total variation is unexplained by the least-squares regression line statistically. Also, the p-value for the deviation of the left and right in the front axle is 0.4839 ~ 0.5755, then it has nonsignificant in the front axle. Therefore, the static braking force inspection system can not reflect the inertia force that there is a load transfer from the rear axle to the front axle during braking. Accordingly, it is necessary to adopt the dynamic braking force inspection system which can reflect the inertia force on the regular vehicle safety inspection in domestic country.