• 한국정밀공학회지
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• 제17권1호
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• pp.129-137
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• 2000

In this paper, a new method of noncontact measurement has been developed for a 3 dimensional topography in semiconductor wafer, implementing a new optical probe based on the precision defocus measurement. The developed technique consists of the new optical probe, precision stages, and the measurement/control system. The basic principle of the technique is to use the reflected slit beam from the specimen surface, and to measure the deviation of the specimen surface. The defocusing distance can be measured by the reflected slit beam, where the defocused image is measured by the proposed optical probe, giving very high resolution. The distance measuring formula has been proposed for the developed probe, using the laws of geometric optics. The precision calibration technique has been applied, giving about 10 nanometer resolution and 72 nanometer of four sigma uncertainty. In order to quantitize the micro pattern in the specimen surface, some efficient analysis algorithms have been developed to analyse the 3D topography pattern and some parameters of the surface. The developed system has been successfully applied to measure the wafer surface, demonstrating the line scanning feature and excellent 3 dimensional measurement capability.

• 센서학회지
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• 제23권1호
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• pp.7-14
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• 2014

Noncontact electrocardiogram (ECG) measurement using capacitive-coupled technique is a very reliable long-term noninvasive health-care remote monitoring system. It can be used continuously without interrupting the daily activities of the user and is one of the most promising developments in health-care technology. However, ECG signal is a very small electric signal. A robust system is needed to separate the clean ECG signal from noise in the measurement environment. Noise may come from many sources around the system, for example, bad contact between the sensor and body, common-mode electrical noise, movement artifacts, and triboelectric effect. Thus, in this paper, the extended Kalman filter (EKF) is applied to denoise a real-time ECG signal in capacitive-coupled sensors. The ECG signal becomes highly stable and noise-free by combining the common analog signal processing and the digital EKF in the processing step. Furthermore, to achieve ubiquitous monitoring, android-based application is developed to process the heart rate in a realtime ECG measurement.

• 대한기계학회논문집A
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• 제38권10호
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• pp.1133-1137
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• 2014

초음파 비선형 파라미터 ${\beta}$는 재료의 미세한 변질을 평가하는데 효과적인 인자로 알려져있다. 그런데 지금까지 대부분의 연구는 접촉식 방법을 이용하여 측정하는 연구가 수행되어왔다. 그러나, 접촉식 방법은 탐촉자와 시편사이의 접촉상태가 측정결과에 큰 영향을 미치기 때문에 측정의 재현성을 보장하기 위해 탐촉자의 접촉상태를 일정하게 유지시키기 위한 부수적인 장치가 필요하다. 이러한 불편함을 해소할 목적으로 본 연구에서는 비접촉식 기법을 도입하였다. 다만 초음파의 송신은 접촉식으로 하고 수신만 비접촉식을 적용함으로써 동일한 조건에서 접촉식으로 수신한 경우와 비접촉식으로 수신한 경우를 비교하고자 하였다. 시편은 시효 처리된 알루미늄 합금을 사용하였고, 두 방식의 측정결과 비선형 파라미터 ${\beta}$의 변화는 유사하게 나타났다. 이로부터 초음파 비선형 특성의 변화를 비접촉식 수신방법으로 용이하게 평가할 수 있음을 확인하였다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1997년도 추계학술대회 논문집
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• pp.254-259
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• 1997

The measurement of surface roughness and waviness by means of noncontact method is an important area to be developed for GAC(Geometrical Adaptive Control) system. This paper deal with the design of noncontact in-process measurement system which measures the surface roughness and waviness during cylindrical grinding. This measuring system is simple and the apparatus proposed is composed of a laser unit, photodetector and optical system. During operation, the surface of a workpiece is continuously scanned by a laser beam. This method makes it possible to detect the surface roughness and waviness along the feed direction by control the spot diameter of laser beam. The experimental results show that the presence of chattering, loading and glazing can be detected sensitively along the feed directions.

• 대한기계학회논문집A
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• 제21권11호
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• pp.1862-1870
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• 1997

A fast and precise technique to measure 3-dimensional coordinates of an object is proposed. It is essential to take the 3-dimensional measurements of the object in design and inspection. Using this developed system a surface model of a complex shape can be constructed. 3-dimensional world coordinates are projected onto a camera plane by the perspective transformation, which plays an important role in this measurement system. According to the shape of the object two measuring methods are proposed. One is rotation of an object and the other is translation of measuring unit. Measuring speed depending on image processing time is obtained as 200 points per second. Measurement resolution i sexperimented by two parameters among others; the angle between the laser beam plane and the camera, and the distance between the camera and the object. As a result of these experiments, it was found that measurement resolution ranges from 0.3mm to 1.0mm. This constructed surface model could be used in manufacturing tools such as rapid prototyping machine.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1063-1066
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• 2003

A flow-meter and its measurement controller was developed for a hydraulic system. This study, for development of positive displacement flow-meter, consist of PIC(Peripheral Interface Controller) controller with MR(Magneto-resistive) sensors. This flow-meter is used valve position indicator for valve control system by hydraulic. The MR sensors are used for the rotation of OVAL gear that detecting device. In the ship environments, consideration that necessary explosive proof. Thus electro device or electro flow-meter needs explosion design for electric circuit. We designed noncontact type flow-meter and evaluated the safety and measuring abilities.

• 한국정밀공학회지
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• 제18권8호
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• pp.40-47
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• 2001

Optical measurement methods make it possible to detect object displacements with high resolution and noncontact measurements. Also, they are very robust against EMI noises and have long operation range. An optical triangulation sensor is one of widely used displacement measurement sensors for its sub-micron resolution, fast response, simple structure, and low cost. However. there are several errors caused by inclinations of a surface. speckle effects, power fluctuations of light sources, and noises of detectors. In this paper, in order to minimize error effects, we performed error analysis and proposed a new structure. Then, we setup a new modeling method and verify it through simulations and experiments. Based on the new model. we propose a new sensor structure and establish design criteria. Finally, we design a signal processing system to overcome a resolution-limited problem of light detectors. The resolution of the proposed system is 0.2${\mu}{\textrm}{m}$ in 5mm operating range.

• 한국산학기술학회논문지
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• 제11권5호
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• pp.1730-1734
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• 2010

원전 2차계통수의 pH를 예측을 위해서는 샘플을 채취, 냉각시킨 후 pH를 측정하게 되는데 이 때 샘플의 온도는 pH를 변화시키는 중요한 요인이 된다. 본 연구에서는 할로겐화 은 광섬유를 이용하여 비접촉식 온도센서를 개발하였고, 열전쌍열을 이용하여 열원으로부터 방출되는 적외선을 측정하였다. 열원과 광섬유 끝단 사이의 거리 및 각도 변화에 따른 광섬유 온도센서의 출력신호를 분석하였으며, 광섬유 온도센서로 측정한 온도범위는 $25{\sim}60^{\circ}C$이다. 본 연구결과를 기초로 원전 2차계통수 pH 샘플의 온도를 측정하기 위해 할로겐화 은 광섬유를 이용한 비접촉식 온도센서의 개발이 가능할 것으로 기대된다.

• ETRI Journal
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• 제36권3호
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• pp.361-366
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• 2014

In this paper, a new, simple capacitive tilt sensor with a metallic ball is proposed. The proposed tilt sensor has only two electrodes and a metallic ball, and this design assists in managing the inherent contact problem in measuring tilt angles. Capacitive sensing, compared with other types of tilt sensor, has many advantages such as simplicity, noncontact measurement, long-throw linear displacement, and sub-micron plate spacing. Its design and fabrication process are significantly simpler than previous types of tilt sensors. The dimensions of the prototype tilt sensor are $20mm{\times}20mm$, and the diameter of the polystyrene tube is 5 mm with a tube thickness of 0.15 mm. An analytical study of the prototype capacitive tilt sensor was undertaken, and the experimental results demonstrate the relationship between the tilt angles and measured capacitances compared with the analytical study.

• 한국정밀공학회지
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• 제12권1호
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• pp.5-14
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• 1995

An optical measurement method of three dimensional surface profiles which is named the slit beam projection is suggested and practically implemented. This method is intended especially for noncontact and fast digitization of sculptured surfaces for CAD modeling and die manufacturing. Its basic principles are based on geometric optics. Deatiled optical principles and an sub-pixel image processing technique to enhance the measuring resolutions are described in this study. The measuring performances of the slit beam projection are presented and discussed to demonstrate that an actual measuring accuracy of below .+-. 0.2mm can be achived over the whole measuring range(500mm*300mm*200mm)