• 소음진동
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• 제10권2호
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• pp.269-279
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• 2000

This paper deals with the development of biomechanical model on a seat with backrest support in the vertical direction. Four kinds of biomechanical models are discussed to depict human motion. One DOF model mainly describes z-axis motion of hip, two and three DOF models describe z-axis of hip and head, and while nine DOF model suggested in this study represents more motion than the otehr model. Three kinds of experiments were executed to validate these models. The first one was to measure the acceleration of the floor and hip surface in z-axis, the back surface in x-axis, and the head in z-axis under exciter. From this measurement, the transmissiblities of each subject were obtained. The second one was the measurement of the joint position by the device having pointer and the measurement of contact position between the human body and the seat by body pressure distribution. The third one was the measurement of the seat and back cushion by dummy. The biomechanical model parameters were obtained by matching the simulated to the experimental transmissiblities at the hip, back, and head.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1853-1857
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• 2005

In most of motor-driven motion control systems, an encoder is used to measure a position of the motor and the velocity information is obtained by measuring the position increment over a sampling period. The quantization effect due to limited resolution of the encoder induces some measurement errors, and consequently causes deterioration of the motion performance especially in low velocity. In this paper, we propose a gain-scheduled acceleration estimator which works in wider velocity range than the original acceleration estimator. We investigate and analyze characteristics of the velocity measurement mechanism which takes into account the quantization effect of the encoder. Next, we introduce the acceleration estimator and propose a gain-scheduled acceleration estimator. The bandwidth of the gain-scheduled acceleration estimator is automatically adjusted by the velocity command. Finally, its performance is evaluated by simulation and experiment, and the results are compared with those of a conventional method and the original acceleration estimator.

• 한국정밀공학회지
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• 제31권12호
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• pp.1133-1139
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• 2014

This paper proposes a simple method to improve a sensitivity of a straightness measurement system for a linear stage, which is applied to a system based on a geometric optic method. An optical system for this method is composed of a corner-cube retro-reflector, a ball-lens and a twodimensional position sensitive detector (2D PSD). The effectiveness of the proposed method was examined theoretically, and verified experimentally using a prototype measurement system. The results show that the measuring sensitivity was dependent on the size of the ball-lens and the setup position of PSD from the ball-lens, and that the proposed method is efficient method to improve the measuring sensitivity.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2001년도 Proceedings of 2001 Korea-Japan Joint Seminar on Particle Image Velocimetry
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• pp.100-107
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• 2001

A simple new technique of particle depth position measurement, which can be applied for three-dimensional velocity measurement of fluid flows, is proposed. Two color illumination system that intensity is encoded as a function of z-coordinate is introduced. A calibration procedure is described and a profile of small sphere is detected by using the present method as preliminary test. Then, this method is applied to three-dimensional velocity field measurement of simple flow fields seeded with tracer particles. The motion of the particles is recorded by color 3CCD camera. The particle position in the image plane is read directly from the recorded image and the depth of each particle is measured by calculation of the intensity ratio of encoded two color illumination. Therefore three-dimensional velocity components are reconstructed. Although the result includes to some extent error, the feasibility of the present technique for three-dimensional velocity measurement was confirmed.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집A
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• pp.415-419
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• 2000

Multi-degree-of-freedom (MDOF) displacement measurement Is needed In many application fields: precision machine control, precision assembly, vibration analysis, and so on. This paper presents a new MDOF displacement measurement method using a laser diode (LD), two position-sensitive detectors (PSDs), and a conventional diffraction grating. It utilizes typical features of a diffraction grating to obtain the information of MDOF displacement. MDOF displacement is calculated from the independent coordinate values of the diffracted ray spots on the PSDs. Forward and inverse kinematic problems were solved to compute the MDOF displacement of a rigid body. Experimental results show maximum absolute errors of less than ${\pm}10$ micrometers in translation and ${\pm}30$ arcsecs in rotation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 B
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• pp.833-836
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• 1995

The Position Sensitive Detector(PSD) is an useful which can be used to measurement the position of an incidence light in detail and in real-time. In this paper, light sources, to be predefinded positions, are used as landmarks and the 2-D PSD signals are used to compensate the position of a running mobile robot. To induce the position compensation algorithm, first, we inspect the error factor, make the error model, and evaluate the error covariance matrix between the real position and estimated position in dead reckoning system. Next we obtain an optimal position compensation algorithm to update the estimated position using extended Kalman filler by the relation of the external light position and it's PSD signal. Through the simulation of navigating a robot the effectiveness of the proposed method is confirmed.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2011년도 춘계학술대회 논문집
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• pp.1093-1094
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• 2011

• Journal of Acupuncture Research
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• 제29권5호
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• pp.127-137
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• 2012

Objectives : The purpose of this study is to review on current status of use and measurement condition of heart rate variability(HRV) by reviewing clinical studies published in journal of Korean medicine registered Korea citraion index(KCI). Methods : One hundred twenty articles were found by searching the representative Korean databases. At first analysis was performed by current status of use(journal, academic field of corresponing author, purpose of study, disease of subject, HRV measurement devices, intervention methods and tests compared to HRV). At second analysis was performed by measurement condition(uncontrolled study, relaxation before measurement, measurement position, measurement place, measurement time period and restriction of smoking, alcohol, caffeine, meal). Results : The analysis showed that department of acupuncture & moxibustion, department of oriental neuropsychiatry are major part in journal & academic field. The purpose of study were classified under studies to verify therapeutic effect on normal subject(39%), to verify therapeutic effect on the patients(8%), to investigate characteristics of the patients(34%) and to be compared with other test(19%). Disease of subject & measurement devices in article were so various. Major intervention methods were acupuncture(61.4%), mind-body intervention(19.2%). Studies that measurement condition were not controlled were relax time(24%), measurement position(19%), measurement place(26%), measurement time period(91%) and restriction of smoking, alcohol, caffeine, meal(49%). Conclusions : This study showed that current status of use of HRV is widespread in Korean medicine but more controlled measurement conditon are needed to get more reliable result from clinical studies and to improve diagnosis and treatment of Korean medicine.

• 한국공작기계학회논문집
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• 제10권1호
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• pp.36-42
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• 2001

In this paper, PSD(Position Sensitive Detector) sensor system that estimates position for moving objects in 2D plane is developed. PSD sensor is used to measure the position the position of and incidence light in real-time. To get the position of light source of moving target, a new parameter calibration algorithm and neural network technique are proposed and applied. Real-time position measurements of the mobile robot with light source is examined to validate the proposed method. It is shown that the proposed technique provides accurate position estimation of the moving object.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2006년도 정기학술발표대회 논문집
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• pp.187-193
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• 2006

최근의 과학기술의 발전과 더불어 인공위성을 이용한 GPS 측량시스템의 실용화가 토목을 중심으로 한 건설현장에서도 두드러지고 있다. 특히 측량기준점을 확인하기 어려운 토목현장의 경우에는 GPS 측량의 유용성이 적극적으로 도입되어 실용화 단계에 이르렀다. 그러나 mm단위의 정밀성이 요구되는 건축현장의 경우에는 GPS가 가지는 오차의 크기로 인하여 적용되어 오지 못하다가 최근에 정밀도를 향상시킨 새로운 측량 기술이 개발되어 초고층 건물을 중심으로 적용되고 있다. 본 논문에서는 정확성과 편리성을 획기적으로 개선한 GPS 측량시스템을 세계초고층 건물인 버즈 두바이 현장에 적용한 사례를 소개하고자 한다.