• 태양에너지
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• 제19권4호
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• pp.81-91
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• 1999

The work presented here is a design and development of sun tracking system for the parabolic dish concentrator. Parabolic dish concentrator is mounted on azimuth and elevation tracking mechanism, and controlled to track the sun with computed and measured sun positions. Sun tracking mechanism is composed of 1/30000 speed reducer(3 stages) and 400W AC servomotor for each axis. The nominal tracking speed of each axis is ${\pm}0.6^{\circ}/sec$ and the system has a driving range of $340^{\circ}$ in azimuth and of $135^{\circ}$ in elevation. Sun tracking control system consists of sun sensor, wind speed and direction measurement system, AC servomotor position control system and personal computer as a master controller. Sun sensor detects the sun located within ${\pm}50^{\circ}$ measured from the sun sensor normal direction. Computer computes the sun position, sunrise and sunset times and controls the orientation of parabolic dish concentrator through the AC servomotor position control system. It also makes a decision of whether the system should follow the sun or not based on the information collected from sun sensor and wind speed and direction measurement system. The sun tracking system developed in this work is implemented for the experimental work and shows a good sun tracking performance.

• International Journal of Control, Automation, and Systems
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• 제3권1호
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• pp.130-136
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• 2005

A new optical digitizing system for determining the position of a cursor in three dimensions(3D) and an experimental device for its measurement are presented. A semi-passive system using light intensity modulation, a technology that is well known in radar ranging, is employed in order to overcome precision limitations imposed by background light. This system consists of a charge-coupled device camera placed before a rotating mirror and a light-emitting diode whose intensity is modulated. Using a Fresnel pattern for light modulation, it is verified that a substantial improvement of the signal to noise ratio is realized for the background noise and that a resolution of less than a single pixel can be achieved. This opens the doorway to the realization of high precision 3D digitized measurement. We further propose that a 3D position measurement with a monocular optical system can be realized by a numerical experiment if a linear-period modulated waveform is adopted as the light-modulating one.

• 한국전자파학회논문지
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• 제20권9호
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• pp.943-953
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• 2009

본 논문에서는 추적식 태양광 발전 시스템에 응용하기 위한 태양 위치 측정용 전파 센서 수신기의 설계, 제작 및 성능 실험에 관한 과정 및 결과를 소개한다. 먼저, 전파 센서에 대한 요구 성능인 ${\pm}5^{\circ}$ 이내의 위치 측정 오차 범위를 만족시키기 위한 수신기의 사양을 구하였고, 이를 토대로 수신기를 설계하였다. 설계된 수신기의 시스템 이득 및 잡음 지수의 budget 분석을 통해 설계의 적절성을 점검하였으며, 이 결과를 활용하여 수신 주파수 5.1 GHz, 대역폭 104 MHz로 69 dB의 시스템 이득과 0.46 K 이내의 수신 감도를 갖는 고이득, 고감도 광대역 수신기를 제작하였다. 제작된 수신기와 표준 혼 안테나로 구성된 전파 센서로 흐린 날 실제 태양을 대상으로 실험한 결과, ${\pm}4^{\circ}$ 이내의 오차 범위로 태양의 위치를 실시간으로 측정하는데 성공하여 요구 성능이 만족되었음을 검증하였다.

• The Journal of Korean Physical Therapy
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• 제15권1호
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• pp.119-154
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• 2003

In this paper, the proprioceptive sensitivity was compared by Foot-Hand task method and the effect of the proprioceptive sensitivity and auditory to the standing position between blind and normal children was measured using BPM for 56 children in 7, 8, 9 and 10 years old. There are three measurement methods are used for BPM : Rest, Forward Looking, 'Sound' position. The following conclusions were obtained from the above measurements. 1. In comparison of proprioceptive sensitivity between blind and normal children, there is no significant difference(p > .05). There is no significant difference in comparison of each age group and also there is no difference in each gender group(p > .05). 2. In comparison of standing position measurement between blind and normal children, there is any difference (p > .05) in three measurement(Rest, Forward Looking, 'Sound' position) but there is no significant difference in each gender difference(p > .05). There is any difference between Rest and 'Sound' position of blind children, also there is any difference between Forward Looking and ' Sound ' position, rest and 'Sound' position of normal children(p > .05). 3. There is no significant difference of correlation between proprioceptive sensitivity test and standing position measurement in Pearson correlation coefficient(p > .05).

• 한국지능시스템학회논문지
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• 제26권4호
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• pp.321-326
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• 2016

본 논문에서는 휴대용 휘도측정시스템의 측정위치기반 휘도보정알고리즘을 제안한다. 측정거리와 측정각도에 따라 휘도 값은 변화하며, 측정거리와 측정각도를 고려한 알고리즘을 적용하여 기존에 개발된 영상기반 휘도측정시스템의 오차를 개선한다. 카메라 영상기반의 휘도 정보를 정확하게 획득하는 면측정방법을 제안하기 위해서 점휘도계로 측정대상물과의 측정각도에 따른 휘도 값의 변화를 측정한다. 측정거리, 측정각도와 휘도 값 간의 연관성을 수식으로 나타내었고, 측정위치를 고려한 알고리즘을 제안한다. 실험용 간판을 대상으로 점휘도계와 제안한 휘도측정시스템을 비교 평가 실험하고 제안한 휘도측정시스템의 성능을 검증하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 영호남 합동 학술대회 및 춘계학술대회 논문집 센서 박막 기술교육
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• pp.125-129
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• 2006

The analysis of the depth measurement system with multi-sensors (laser, camera, mirror) has been done and the parameter calibration technique has been proposed. In the proposed depth measurement system, the laser beam is reflected to the object by the rotating mirror and again the position of the laser beam is observed through the same mirror by the camera. The depth of the object pointed by the laser beam is computed depending on the pixel position on the CCD. There involved several number of internal and external parameters such as inter-pixel distance, focal length, position and orientation of the system components in the depth measurement error. In this paper, it is shown through the error sensitivity analysis of the parameters that the most important parameters in the sense of error sources are the angle of the laser beam and the inter pixel distance.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1994년도 Proceedings of the Korea Automatic Control Conference, 9th (KACC) ; Taejeon, Korea; 17-20 Oct. 1994
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• pp.129-133
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• 1994

Presented are closed-form expressions of the steady-state solution for the three-state exponentially correlated acceleration(ECA) target-tracking filter. The steady-state solution is derived based on Vaughan's approach for the case that the measurements of target position and velocity are available at discrete points in time. The solution for the ECA filter using only position measurements is obtained as a special case of the presented results.

• 한국정밀공학회지
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• 제24권6호
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• pp.66-71
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• 2007

Development of a locomotive mechanism for the capsule type endoscopes will largely enhance their ability to diagnose disease of digestive organs. As a part of it, there should be provided a detection device of their position in human organs for the purpose of observation and motion control. In this paper, a permanent magnet outside human body was employed to project magnetic field on a capsule type endoscope, while its position dependent flux density was measured by three hall-effect sensors which were orthogonally installed inside the capsule. In order to detect the 2-D position data of the capsule with three hall-effect sensors including the roll, pitch and yaw angle, the permanent magnet was extra translated during the measurement. In this way, the 2-D coordinates and three rotation angles of a capsule endoscope on the same motion plane with the permanent magnet could be detected. The working principle and performance test results of the capsule position detection device were introduced in this paper showing that they could be also applied to 6-DOF position detection.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 C
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• pp.1562-1564
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• 1994

In this paper, we describe that the acoustic PD detection is examined in the various structures and position shapes of sensors. We find that the acoustic waves rate the complexity in various structures and position shapes of sensors may reduce the complexity of the acoustic wave in the PD detection of transformers.

• The Journal of Korean Physical Therapy
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• 제31권6호
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• pp.333-338
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• 2019

Purpose: Although previous studies on the screw-home movement (SHM) for autopsy specimen and walking of living persons conducted, the possibility of acquiring SHM based on inertial measurement units received little attention. This study aimed to investigate the possibility of measuring SHM for the non-weighted bearing using a micro-electro-mechanical system-based wearable motion capture system (MEMSS). Methods: MEMSS and camera-based motion analysis systems were used to obtain kinematic data of the knee joint. The knee joint moved from the flexion position to a fully extended position and then back to the start point. The coefficient of multiple correlation and the difference in the range of motion were used to assess the waveform similarity in the movement measured by two measurement systems. Results: The waveform similarity in the sagittal plane was excellent and the in the transverse plane was good. Significant differences were found in the sagittal plane between the two systems (p<0.05). However, there was no significant difference in the transverse plane between the two systems (p>0.05). Conclusion: The SHM during the passive motion without muscle contraction in the non-weighted bearing appeared in the entire range. We thought that the MEMSS could be easily applied to the acquisition of biomechanical data on the knee related to physical therapy.