• 대한수학교육학회지:학교수학
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• 제12권1호
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• pp.45-60
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• 2010

학교수학에서 '각도'는 용어로서의 실효성을 상실한 반면에, '각의 크기' 라는 표현이 우세한 만큼, 그 표현의 수용을 고려할 필요가 있다. 교과서에서 각의 크기는 변의 길이와 관계없이 두 변이 벌어진 정도에 따라 다르다는 것을 명시할 필요가 있다. 해설서의 내용과 교과서의 내용을 일치시켜야 한다. 교과서에서는 각의 크기를 측정하기 위한 임의단위를 취급하지 않는다. 임의단위에 의한 각의 크기의 측정을 생각할 수는 있지만, 그것이 그다지 행해지지 않는다는 실정을 받아들여, 해설서에서 그것을 요구하지 않는 것을 고려할 필요가 있다. 해설서에서 1직각의 표준단위로서의 역할을 명시할 필요가 있고, 교과서에서도 그것을 활용하는 장면을 제시해야 한다. 교과서에서는 삼각형의 세 각의 크기의 합을 구하는 과정과 사각형의 네 각의 크기의 합을 구하기 위해 삼각형과 사각형을 각각 잘라 붙이는 과정에서, 학생들이 크기가 180도인 각과 360도인 각이 그림으로 어떻게 표현될 수 있는지 알고 있다는 것을 전제로 하고 있다. 그것은 비약이다.

• The Journal of Korean Physical Therapy
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• 제31권1호
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• pp.35-39
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• 2019

Purpose: The purpose of this study was to assess the intra-rater and inter-rater reliability and validity of pelvic tilting angle measurements using a smart phone-based inclinometer (Clino) compared to a palpation meter (PALM) in the standing and sitting position. This study used an interchangeable method with Clino to measure the pelvic tilting angle in the standing and sitting positions. Methods: Twenty healthy subjects were recruited. Measurements of the pelvic tilting angle in the standing and sitting positions were obtained by two examiners using the Clino and PALM. A resting session was conducted 10 minutes later to assess the intra and inter rater reliability. To assess validity of the measurement using Clino, a PALM was used as the gold standard. The intra-class correlation coefficient (ICC) was used to determine the intra and inter rater reliability of Clino and a PALM. To assess the validity, the Pearson correlation coefficients were used for two measurement techniques to measure the pelvic tilting angle in the standing and sitting positions. The statistical significance was set to ${\alpha}=0.05$. Results: Measurements of the pelvic tilt had high inter-rater reliability in the standing (ICC=0.82) and sitting (ICC=0.88) positions using Clino and intra-rater reliability in the standing (ICC=0.87) and sitting (ICC=0.91) positions using Clino. Measurements of the pelvic tilt had high validity by a comparison of PALM and Clino in the standing (r=0.83) and sitting (r=0.89) positions (p<0.05). Conclusion: The use of Clino can be recommended as a tool to replace the PALM and measure the pelvic tilt angle in the standing and sitting positions while maintaining the clinical reliability and validity.

• 산업기술연구
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• 제22권A호
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• pp.153-159
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• 2002

This paper is an experimental work of estimating friction angle of very coarse grained soil such as rubble mound by performing laboratory experiments. Two crushed rocks of rubble mound were used for tests. Triaxial compression tests with drained conditions were performed to measure friction angles of soils prepared by mixing the crushed soil having an identical coefficient of uniformity with different maximum grain size distribution. Centrifuge model experiments with those soils were also performed to measure angle of repose and to estimate friction angle of soil from measuring the slope of slip line in the active stress state. Model tests were carried out by changing the G-levels of 1G and 50G. From triaxial compression tests, the measured value of friction angle of soil is in the range of $41{\sim}57^{\circ}$. The measured value of repose angle is in the range of $32{\sim}35^{\circ}$. The values of friction angle are found not so sensitive to the maximum grain size of soil as long as the coefficient of uniformity is identical. Estimated value of friction angle from measuring the slope of slip line in the active stress state is in the range of $30{\sim}46^{\circ}$. Thus, the estimated angle of friction are found to be greater in the order of the measured angle of repose, the estimated value from the slope of active state, and triaxial compression test results. On the other hand, the measured values of friction angle from triaxial tests were compared with empirical equations, based on the relation between friction angle and void ratio. Equations proposed by Helenelund(l966) and Hansen(1967) found to be relatively reliable to estimate friction angles of soil.

• 대한물리의학회지
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• 제5권1호
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• pp.71-79
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• 2010

Purpose : To investigate of gait change as Q-angle in chronic knee osteoarthritis patients. Methods : Participated osteoarthritis disease patients(n=16) and normal adults(n=16). gait measure was used by GaitRite and Q-angle measure was used by tape measur

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.107.5-107
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• 2002

In this paper, a kinematic optimal design of a new paralleltype rolling mill based upon two Stewart platforms manipulator is investigated. The objective of this new parallel-type rolling mill is to permit an integrated control of the strip thickness, strip shape, pair crossing angle, uniform wear of the rolls, and tension of the strip. A manipulability measure, as the ratio of the manipulability ellipsoid volume and the condition number of a split Jacobian matrix, is defined. Two kinematic parameters, the radius of the base and the angle between two neighboring joints, are optimally designed by maximizing the global manipulability measure in the entire workspace.

• 한국생산제조학회지
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• 제20권5호
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• pp.623-631
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• 2011

Light emitting diodes (LEDs) which can produce uniform luminescence need a very difficult and complex procedure because LEDs have strong and straight optical property. One of the major parameters for LED production is the determination of the viewing angle. However, in the present, there is still no available production technology to measure LED viewing angle and optical property. In this study, we developed a five-side LED viewing angle and optical property measurement system, having a source meter that uses a high speed switching photo relay instead of a mercury relay. This new measurement system can measure the viewing angle at a very high accuracy of ${\pm}0.66^{\circ}$. This new technology presents a great potential for fast and reliable LED mass production, which can significantly cut down the cost from savings in production time.

• 한국전문물리치료학회지
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• 제19권4호
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• pp.55-60
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• 2012

The trochanteric prominence angle test (TPAT) has been used to measure the femoral anteversion angle between the tibial crest and the vertical line. However, the exact anatomical reference of the tibial crest has not yet been identified in the literature. Thus, the purposes of this research were twofold: first, to compare the femoral anteversion angle measured at three different anatomical references of the tibial crest (the proximal tibial crest, the proximal third of tibial crest, and the proximal half of tibial crest) and, second, to determine inter-and intra-rater reliabilities of the femoral anteversion angle measured at these three different anatomical references of the tibial crest during the TPAT. We recruited 14 healthy subjects, and a total of 28 legs were examined. The TPAT was measured using a digital inclinometer. A 1-way repeated-measure analysis of variance was used to compare the femoral anteversion angle measured at three different anatomical references of the tibial crest, and intraclass correlation coefficients (ICCs) were calculated to determine reliability. The femoral anteversion angle measured at the proximal tibial crest was significantly higher than that at the proximal third of the tibial crest and the proximal half of the tibial crest. The inter-and intra-rater reliabilities of femoral anteversion angle were measured at three anatomic references of the tibial crest were all found to be high during the TPAT (ICC=.9 0~.98). In conclusion, clinicians should recognize that the different degrees of the femoral anteversion angle could be measured when different anatomical references of the tibial crest were used, and that reliabilities were high when an exact anatomical reference of the tibial crest was used during the TPAT.

• 대한수학교육학회지:수학교육학연구
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• 제27권4호
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• pp.833-855
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• 2017

본 연구는 삼각함수 각의 크기를 표현하기 위해 라디안 단위를 새로 도입하는 이유로서 호의 길이를 이용한 각의 측도라는 호도법의 의미와, 삼각함수의 정의역이 일반각을 나타내는 실수로 확장된 이유를 재조명하고자 한다. 이를 위해 라디안 개념의 다각적인 교수학적 분석을 하고자, 역사적, 수학적, 응용수학적 분석을 수행하였다. 이를 통해 첫째, 호도법은 각도에 내재된 본질이고, 라디안은 원주율(${\pi}$)과 밀접한 이론적이고 절대적인 단위이며, 삼각함수를 실함수로 함을 밝혔다. 둘째, 라디안은 동심원에서 비와 비례 관계의 공변성을 거쳐 불변성을 인식하도록 할 것, 라디안으로 표현한 코사인과 사인의 직교성이 임의의 함수의 급수 표현을 가능하게 함, 라디안은 호의 길이를 반지름으로 측도하는 가장 단순화한 표준임을 인식하도록 할 것, 분할 전략을 통해 육십분법과의 연결성을 찾을 수 있음을 밝혔다. 셋째, 각과 각도의 구별로, 라디안 단위의 생략 여부에 대한 정당화와, 호와 반지름 사이의 곱셈 관계 전략이 필요함을 밝혔다. 이로써 도출한 교수학적 시사점은 라디안 개념의 유용성과 가치를 드러내고, 호도법의 실질적인 지도에 기여할 수 있다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권2호
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• pp.1615-1618
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• 2007

Performances of LCDs are generally evaluated in terms of luminance and color versus viewing angle. In the present paper we show that this type of display can be favorably characterized in terms of polarization. We show that ELDIM EZContrast instrument can be used to measure the degree of polarization the light and the ellipticity and polarization direction of the polarized component. This measurement is made versus incidence angle between 0 and $88{\circ}$ and for all the azimuth angles. Important differences between the displays can be detected and related to their internal structures when luminance and color profiles are quite similar.

• Journal of Power Electronics
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• 제10권3호
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• pp.300-305
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• 2010

This paper presents a two Hall sensor method for rotor angle detection in permanent magnet synchronous motors (PMSM). To minimize the implementation complexity, the system is designed to measure the edge field of permanent magnet pieces. However, there are nonlinearities in the measured values of the edge field. In this work, an angle correction algorithm is proposed, and the improvements in accuracy are verified through experiments. Finally, a field orientation controller is constructed with the proposed angle detection algorithm.