가속도계를 이용한 제동직전의 차속추정방법에 관한 연구 (A study on the presumption method of automobile velocity just before braking, using a accelerometer.)
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- 오토저널
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- 제2권1호
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- pp.32-38
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- 1980
In the case of a automobile marking skid on road for a period of braking, in general, the automobile velocity just before rapid braking can be obtained by evaluating the coefficient of friction between tires and road. Up to now, the coefficient of friction has been derived from mean velocity measured by a time watch, but the automobile velocity obtained in this manner would be deviated from actual value considerably, due to errors arising from not only measuring time but other various factors. In this paper the presumption method of automobile velocity by accelerometer is presented so as to improve the accuracy of measurement, and to determine the velocity readily. The results obtained in this experiment show that the frictional coefficients between tires and road under the given experimental conditions are considered to take linear relation over the fixed velocity limits 30km/h to 50km/h while for the same limits of velocities the coefficients of friction by the time watch method are not valid ar low velocity range. It will be seen that the former is simple and reliable whilst the latter is cumbersome and unreliable.
최근 들어 리모델링시장이 점차 신축시장의 대체시장으로 부각되고, 재건축아파트에 대한 안전진단의 문제가 사회의 주요 관심사가 되면서 기존 콘크리트 구조체의 상태에 대해 체계적이고 과학적인 구조물 진단 및 평가가 요구되고 있으며, 비파괴 시험방법에 의한 콘크리트 압축강도를 추정하기 위한 데이터의 신뢰성에 대한 중요성이 점점 증대되고 있다. 본 연구에서는 선 타격 개념의 반발도 시험기를 적용하여 콘크리트 압축강도 추정의 신뢰성을 향상시키는 방안을 모색하고, 재령 및 타격각도에 따라 선 타격 반발도 시험기에 적용할 수 있는 압축강도 추정식을 제안하고자 하였다. 연구 결과, 선 타격 반발도 시험기는 재령별, 타격각도별로 별도의 추정식을 제안하는 것이 콘크리트 압축강도 추정의 신뢰성을 향상시키는데 긍정적인 것으로 나타났으며, 압축강도와 반발도 사이의 상관관계는 초기 및 중기재령, 그리고 타격각도별로 초기재령
This study is aimed at the application of the apparel size system to be applied for the Internet shopping mall in Korea. Especially this is focused on the presumption of the body measurement according to the age groups and the figure groups. In this regard, a sizing system is to be developed that could be used to approach consumers more easily and provide more fitness and accuracy in terms of size. The target study was on a group of women nineteen to forty-nine years of age. The 4th National Anthropometry Survey data were used in the examination. The results in the study are as follows ; (1) On the Internet apparel shopping malls in relation with this study, no matter what size in the ready-to-wear enterprises was selected by the consumers who once put their information in the member registration, the most appropriate sizes for them are automatically given and transferred to the order forms of chosen enterprises with aid of internal programs of the internet webpage. In addition, when consumers enter their body sizes in the units that are familiar to them, such as inches or centimeters, the units are automatically programed so that they can be converted for the sake of convenience. ; (2) To extract an estimation equation of body size through Multiple Regression Analysis, the circumferences of chest and hip could be presumed by stature, weight, and waist circumference of which most consumers were well aware. For more accurate regression equations, groupings were made in the three categories of age(19∼29/30∼39/40∼49) and in the three body types(Type N, A and H). Then, the regression equations were established for three sectors,