• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 봄 학술논문 발표대회
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• pp.67-68
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• 2023

After mixing the pozzolan-based powder and water repellent with porosity into the cement mortar, microanalysis and measurement of the water repellent contact angle confirmed that the NZS specimen using natural zeolite had the highest contact angle. The specific surface area is increased due to the porosity of natural zeolite, so the adhesion of silane-siloxane is relatively better than that of FA, and it is judged to have a uniform distribution inside the mortar.

• 대한인간공학회지
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• 제25권2호
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• pp.51-62
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• 2006

In assessing risks related to working posture, pictures of postures are taken from various directions, which can be a source of observation error. Joint postures of the neck, lower back, knee, shoulder, and elbow were taken from 7 different viewing angles and 19 observers estimated joint angles by observing the pictures in 2-dimensional display. The joint angles were also measured using an optoelectronic motion measurement system. The estimation error increased as the viewing angle varies from the right side of the human body, but the patterns differ according to which joint angles were being observed. Guidelines to increase the validity of observation of joint angles were presented based on the results. In general, it is recommended to maintain the viewing angle within 20 degrees from the right side of the human body, while different ranges of viewing angle are recommended for each joint angle.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.69-72
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• 2002

The geometry parameter of tool such as rake angle and clearance angle is defined clearly to solve the difference in communication between design and measurement stage. Using the developed simulation program, wheel is properly determined and end mill can be manufactured accurately. The performance test with well defined end mill provides sufficient information to decide optimal geometry. For machining hardened steel, end mills are designed and manufactured. Optimal rake angle and clearance angle is obtained from performance test. A specific software for automatic end mill production is developed far simulation and fur generation of NC code as Cad/CAM system.

• 한국전기전자재료학회논문지
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• 제14권7호
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• pp.595-599
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• 2001

The mechanisms of pretilt angle generation for a nematic liquid cystal (NLC) using a photodimerization method with obliquely polarized UV exposure on the various new photo-crosslinkable polymer were studied. A good thermal stability of all the photo-crosslinkable polymers was obtained by thermogravimetric analysis (TGA) measurement until 450$\^{C}$. High pretilt angle of the NLC was observed by polarized UV exposure on the three kinds of the photo-crosslinkable polymers containing biphenyl(BP), decyl(de), and cholesteryl(chol) group, respectively. However, the low pretilt angle of the NLC was measured by obliquely polarized UV exposure on the two kinds of the photo-crosslinkable polymers containing fluorine and chalcone group. Consequently, the high NLC angle generated is attributable to the biphenyl and alkyl moieties, and photo-dimerized chalcone group of the photopolymer.

• 제어로봇시스템학회논문지
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• 제16권10호
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• pp.991-996
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• 2010

In this paper, a new indoor positioning system based on incident angle measurement of infrared sensor has been suggested. Though there have been various researches on indoor positioning systems using vision sensor or ultrasonic sensor, they have not only advantages, but also disadvantages. In a new positioning system, there are three infrared emitters on fixed known positions. An incident angle sensor measures the angle differences between each two emitters. Mathematical problems to determine the position with angle differences and position information of emitters has been solved. Simulations and experiments have been implemented to show the performance of this new positioning system. The results of simulation were good. Since there existed problems of noise and signal conditioning, the experimented has been implemented in limited area. But the results were acceptable. This new positioning method can be applied to any indoor systems that need absolute position information.

• 한국전자파학회논문지
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• 제27권6호
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• pp.539-544
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• 2016

본 논문에서는 위상비교모노펄스에서 근접한 두 표적의 위치를 추정하는 방법을 제시하였다. 제안한 방법은 Sherman의 기법을 근간으로 하기 때문에 기존 다른 기법들과 달리 단일표적상황에서도 사용할 수 있으며, 오직 단일 펄스만을 사용하여 근접한 두 표적의 위치를 추정하기 때문에 기존 Sherman이 제시한 기법의 단점도 개선할 수 있었다. 제안한 방법의 각도 추정 정확도는 시뮬레이션을 통해 증명하였다.

• 한국의류학회지
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• 제15권4호
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• pp.437-445
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• 1991

The effect of diameter of rods or fibers on contact angle was studied in a vertical rod configuration. A contact angle measuring device described in the previous paper was optimized for the measurement of small-diameter fibers. It was shown that contact angles of water and hexadecane on nylon 6 monofilsments and glass rods increased with decrease of diameter below a critical diameter, which varied from one system to another. Beyond the critical value, contact angle of the liquid on the vertical glass rod reached to an equilibrium value which is equal to the unique value of the contact angle of the liquid drop on the horizontal glass plate.

• Journal of Electrical Engineering and Technology
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• 제13권3호
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• pp.1363-1370
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• 2018

In visible light (VL) positioning based on angle of arrival (AOA) estimation for smart indoor service, the AOA parameters obtained at the receiver has sometimes a random and distributed angle form instead of a point angle form due to the multipath transfer of the actual visible light and short positioning distance. The AOA estimation of a VL signal with a random and parametric distributed angle form may give incorrect AOA parameter estimates, which may result in poor VL positioning performance. In this paper, we classify the AOA parameters of the received VL signal into three forms according to the actual positioning channel environment and consider the short-range VL positioning method. We propose a subspace-based AOA parameter estimation technique and a data fusion method, and analyzed the proposed method by simulation and the measurement of the real VL channel characteristics.

• 한국자기학회지
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• 제24권1호
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• pp.22-27
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• 2014

자북을 지시하는 방위각 측정용 센서는 항공기와 선박이나 스마트폰 등에 널리 사용되고 있다. 센서의 좌표계가 회전을 하였을 경우도 방위각(azimuth angle) 및 회전각(roll angle)를 지시할 수 있게 하기위하여 3-축의 가속도 센서가 추가로 사용된다. 본 연구에서는 방위각센서에 부착된 3-축의 자기장센서의 특성을 측정하거나, 방위각센서용 3-축의 자기장센서를 개발하기 위하여 3-축의 자기장센서의 방위각 특성을 측정할 수 있는 장치를 개발 제작하였다. 3-축의 자기장발생을 위해서 직경이 290 mm 이상인 3-축의 헬름홀쯔 코일을 사용하여 코일 중심 ${\pm}30mm$ 범위에서 자기장의 분포의 균일도가 0.2 % 이내가 되게 하였다. 비자성실험실이 아닌 일반실험실에서도 실험이 가능하게 소형의 헬름홀쯔 코일과 3-축의 마그네토미터를 사용, 환경자기장(지구자기장+건축물에 의한 자기장)을 보상하고 시험하고자하는 자기장을 컴퓨터 소프트웨어로 제어를 할 수 있게 시험 장치를 고안하였다. 제작된 장치는 자기장을 0.2 % 정확도로, 직각도를 $0.2^{\circ}$, 환경자기장을 10 nT 이하로 보상할 수 있었다. 또한 제작된 장치의 성능검증을 위하여 상용의 방위각센서에 대하여, 그 특성을 측정하여보았다.

• 대한두개안면성형외과학회지
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• 제11권1호
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• pp.45-48
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• 2010

Purpose: After surgical interventions of mandible fractures, facial asymmetry can be occurred, and it leads to serious problems for patients. This can be solved by mandible angle ostectomy. Methods: A 19-year-old male underwent percutaneous surgical intervention for left mandibular angle and right parasymphyseal fractures 3.5 years ago. The left angle was protruded compared to the other side. Using a percutaneous approach, $4.5{\times}1cm$ sized piece of mandible angle was sawed off. For the right angle, intraoral approach was performed for angle ostectomy, and the angle was sawed off by a size of $4{\times}1cm$, using a pattern based on the piece from the left side. Results: After surgery, no complications such as subcondylar fractures, refractures, insufficient corrections, secondary angle formations, hematomas, and transient nerve palsies were seen, and symmetric correction of mandible angles were done. Conclusion: In facial asymmetries due to mandibular fractures, mandible ostectomy could be a solution. Using the bone section from the contralateral side, measurement of the amount of bone sawed off was possible, and via percutaneous approach on the previously operated site with simultaneous scar revision, and intraoral approach for the contralateral side, cosmetically satisfactory result was obtained.