• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.2
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• pp.188-194
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• 2000

Thermochromic liquid crystal reflect a unique color at even temperature. Therefore, they have been successfully applied to non-intrusive heat transfer research. Hue capturing method is widely used in the quantitative measurement from the TLC image. However it is affected by several measurement conditions. The distances of camera and light source have little influence on the color, but the value of hue is seriously affected by the measurement angle. In this study, the hue capturing method is improved by considering the effect of measurement angle. This improved calibration method can diminish the misreading of temperature caused by curvature of test surface.

• Journal of the Korean Wood Science and Technology
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• v.41 no.5
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• pp.399-405
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• 2013

This study demonstrates the utilization of light microscopy and Fast Fourier Transform-Peak Finding (FPF) method for microfibril angle (MFA) measurement from unstained sections of red pine (Pinus densiflora). To obtain an image with optimal contrast and resolution for MFA measurement, effects of numerical aperture (NA) of condenser lens and color filters were investigated. About 60% of NA of the maximum condenser NA produced an image with optimal contrast, but a color filter with short wavelength range (DAPI) created images with improved resolution. Manual angle measurement and the FPF method were applied to the image with optimal contrast for MFA measurement. The experimental results from the FPF method were considered to be more repeatable and less subjective than those from the manual angle measurement.

• Physical Therapy Korea
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• v.20 no.2
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• pp.60-68
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• 2013

The purpose of this study was to assess the intra-rater test-retest reliability of tibial external rotation angle measurement using a smartphone-based photographic goniometer, DrGoniometer (DrG) compared to a three-dimensional motion analysis system (Vicon). The current study showed an interchangeable method using DrG to measure the tibial external rotation angle in standing knee flexion at $90^{\circ}$. Twelve healthy subjects participated in this study. A rest session was conducted 30 minutes later for within-day reliability and five days later for between-day intra-rater test-retest reliability. To assess the validity of the measurement using DrG, we used a three dimensional motion analysis system as a gold standard to measure the angle of tibial external rotation. Intra-class correlation coefficient (ICC) and the standard error of measurement (SEM) values were used to determine the within- and between- day intra-rater test-retest reliability of using DrG and a three dimensional motion analysis system. To assess validity, Pearson correlation coefficients were used for two measurement techniques. The measurement for tibial external rotation had high intra-rater test-retest reliability of within-day (ICC=.88) and between-day (ICC=.83) reliability using DrG and of within-day (ICC=.93) and between-day (ICC=.77) reliability using a three-dimentional motion analysis system. Tibial external rotation angle measurement using DrG was highly correlated with those of the three-dimensional motion analysis system (r=.86). These results represented that the tibial external rotation angle measurement using DrG showed acceptable reliability and validity compared with the use of three-dimensional motion analysis system.

• International Journal of Aeronautical and Space Sciences
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• v.14 no.4
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• pp.379-386
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• 2013

The hemispherical resonator gyroscope is a type of vibratory gyroscope, which can measure angle or angular rate, based on its operating mode. This paper deals with the case when the hemispherical resonator gyroscope is operated in angle measurement mode. In angle measurement mode, the resonator pattern angle precesses, with respect to the external rotation input, by the principle of the Coriolis effect, so that the external rotation can be estimated, by measuring the amount of precession angle. However, this pattern angle drifts, due to the manufacturing error of the resonator. Since the drift effect causes degradation of the angle estimation performance of the resonator, the corresponding drift compensation control should be performed, to enhance the estimation performance. In this paper, a mathematical model of the hemispherical resonator gyro is first introduced. By using the mathematical model, a nonlinear observer for imperfection parameter estimation, and the corresponding compensation controller are designed to operate hemispherical resonator gyros, as angle measurement sensors.

• The Journal of Korean Physical Therapy
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• v.27 no.3
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• pp.154-158
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• 2015

Purpose: The purpose of this study was to propose a new reference point for measurement of the infrasternal angle and to investigate the intra- and inter-rater reliabilities of infrasternal angle measurement using photographs. Methods: Twenty-four healthy male college students participated as subjects in this study. Photographs were taken of subjects in two postures, one standing with the shoulders relaxed and one standing with the shoulders at $150^{\circ}$ abduction. All photographs were analyzed using Image J software. Raters used the photographs to measure the infrasternal angle between the xiphoid process, the medial margin of rib and navel on the right and left sides. The reliability of the infrasternal angle measurement was assessed by means of intraclass correlation coefficients [ICC (3,1)]. The level of statistical significance was set at p<0.05. Results: The intra- and inter-rater reliabilities of the infrasternal angle measurement for the right side at rest were excellent (ICC=0.866 and 0.813, respectively), as were those for the left side at rest (ICC=0.919 and 0.846, respectively). At $150^{\circ}$ shoulder abduction, the intra- and inter-rater reliabilities for measurement of the infrasternal angle on the right side were excellent (ICC=0.972 and 0.778, respectively), as were those for the left side (ICC=0.914 and 0.826, respectively). Conclusion: These findings suggest that this technique can be successfully used to measure the infrasternal angle, thus suggesting a new reference point for determining the length of the internal oblique and external oblique muscles in clinical situations.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.1
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• pp.203-209
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• 2009

The purpose of this study is to develop a minimally constraint joint angle measurement system for the feedback control of FES (functional electrical stimulation) locomotion. Feedback control is desirable for the efficient FES locomotion, however, the simple on-off control schemes are mainly used in clinic because the currently available angle measurement systems are heavily constraint or cosmetically poor. We designed a new angle measurement system consisting of a magnet and magnetic sensors located below and above the ankle joint, respectively, in the rear side of ipsilateral leg. Two magnetic sensors are arranged so that the sensing axes are perpendicular each other. Multiple positions of sensors attachment on the shank part of the ankle joint model and also human ankle joint were selected and the accuracy of the measured angle at each position was investigated. The reference ankle joint angle was measured by potentiometer and motion capture system. The ankle joint angle was determined from the fitting curve of the reference angle and magnetic flux density relationship. The errors of the measured angle were calculated at each sensor position for the ankle range of motion (ROM) $-20{\sim}15$ degrees (dorsiflexion as positive) which covers the ankle ROM of both stroke patients and normal subjects during locomotion. The error was the smallest with the sensor at the position 1 which was the nearest position to the ankle joint. In case of human experiment, the RMS (root mean square) errors were $0.51{\pm}1.78(0.31{\sim}0.64)$ degrees and the maximum errors were $1.19{\pm}0.46(0.68{\sim}1.58)$ degrees. The proposed system is less constraint and cosmetically better than the existing angle measurement system because the wires are not needed.

• Resources Recycling
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• v.7 no.5
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• pp.41-45
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• 1998

A Hew way of contact angle measurement is derived based on simple geometrical calculation. Without using complicated contact angle measurement instrument. Just measuring the diameter and height of liquid lens made it possible to calculate the contact angle value with a reasonable reliability. To validate the contact angle value obtained by this method, contact angle of the same liquid lens is measured using conventional goniometer and it is verified that two values are nearly same within the limit of observational error.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.537-540
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• 2005

The attitude control, sensors and camera installed on the spacecraft should be located according to the system alignment requirement. The alignment measurement requirement accuracy for the sensors should be below $\pm$0.1. Therefore, Alignment Measurement System which is combined theodolite, Rotating table and digital inclinometer etc., should be used. As the measurement accuracy is required very precise, the appropriate measurement procedure and alignment angle measurement, calculation and shimming work should is accomplished. Consequently, this paper is accomplished the works to align the measurement requirement accuracy throughout alignment measurement and shimming work of installed module and sensor

• Journal of Adhesion and Interface
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• v.15 no.2
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• pp.57-62
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• 2014

Pythagolas rule was used for investigation of static contact angle in particular figures. Static contact angle measurement was important to evaluate the wettability between solid and liquid. Optimum measurement method and standardization of calculation for static contact angle were investigated for practical application. Optimum diameter of droplet for static contact angle measurement was confirmed as 1 mm. Contact angle measurement using Pythagolas rule was also used to calculate advancing, receding angle and wettability of different surface condition. At last, it was concluded that the Pythagolas rule method was more accurate than general lineation method for static contact angle measurement.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.12
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• pp.38-43
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• 2013

In this paper, the location measurement method for the reliable location data using ultrasonic sensors is proposed for the dimming control of the LED flat lamp. The measurement errors depending on the reflection angle of the object have to be considered to obtain the reliable location data in the ultrasonic sensors. In the experiment, the cause of the measurement errors depending on reflection angle is analyzed and velocity change of ultrasonic wave depending on reflection angle is measured. And the location measurement method depending on velocity change of ultrasonic wave is proposed. From the results, the average absolute deviation of the x-coordinates was 1.47cm when the location measurement method was considered, and it was closer to the true values than the average absolute deviation of the x-coordinates which was 5.89cm without regard to the reflection angle.