• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1364-1369
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• 2004

New method for the design, fabrication, and calibration of micro-machined heat flux sensor has been developed. Two types of micro-machined heat flux sensor having different thicknesses of the thermal-resistance layer are fabricated using the MEMS technique. Photo-resist patterning using a chrome mask, bulk-etching and copper-nickel sputtering using a shadow mask are applied to make heat flux sensors, which are calibrated in the convection-type heat flux calibration facility. The sensitivity of the device varies with thermal-resistance layer, and hence can be used to measure the heat flux in heat-transfer phenomena.

• 한국초전도ㆍ저온공학회논문지
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• 제14권4호
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• pp.46-49
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• 2012

The selection of the temperature sensor in the cryogenic system depends on the temperature range, shape and accuracy. The accuracy of the temperature sensor is essential to improve the reliability of experiment. We have developed the variable temperature cryostat using a two-stage cryocooler. In order to reduce heat load, thermal shield is installed at the first stage with MLI (Multiple layer insulation). We have also developed the sensor holder calibrating more than twenty sensors at the same time for saving time and money. The system can calibrate sensor at variable temperature by controlling electric heater. In this paper, we present design and fabrication of variable temperature cryostat and representative result of Cernox sensor calibration.

• 한국운동역학회지
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• 제13권1호
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• pp.1-12
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• 2003

The purpose of this study was to design the method of 3D space calibration to reduce RMSE by statistical analysis when using the DLT algorithm and control frame. Control frame for 3D space calibration was consist of $1{\times}3{\times}2m$ and 162 contort points adhere to it. For calculate of 3D coordination used two methods about 2D coordination on image frame, 2D coordinate on each image frame and mean coordination. The methods of statistical analysis used one-way ANOVA and T-test. Significant level was ${\alpha}=.05$. The compose of methods for reduce RMSE were as follow. 1. Use the control frame composed of 24-44 control points arranged equally. 2. When photographing, locate control frame to center of image plane(image frame) o. use the lens of a few distortion. 3. When calculate of 3D coordination, use mean of 2D coordinate obtainable from all image frames.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2000년도 학술발표회 논문집
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• pp.3-10
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• 2000

A newly developed heuristic algorithm, Harmony Search, is applied to the parameter calibration problem of the nonlinear Muskingum model. The Harmony Search could, mimicking the improvisation of music players, find better parameter values for in the nonlinear Muskingum model than five other methods including another heuristic method, genetic algorithm, in the aspect of SSQ (the sum of the square of the deviations between the observed and routed outflows) as well as in the aspects of SAD (the sum of the absolute value of the deviations), DPO (deviations of peak of routed and actual flows) and DPOT (deviations of peak time of rented and actual outflow). Harmony Search also has the advantage that it does not require the process of assuming the initial values of design parameters. The sensitivity analysis of Harmony Memory Considering Rate showed that relatively large values of Harmony Memory Considering Rate makes the Harmony Search converse to a better solution.

• 한국측량학회지
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• 제24권3호
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• pp.281-288
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• 2006

최근 비 측정용 디지털 카메라의 화소수가 급증하고, 카메라 단가 또한 저렴해져 문화재 및 시설물의 3차원 공간 측량 등에도 이를 활용할 수 있게 되었다. 그러나 비 측정용 카메라를 측량용으로 활용하기 위해서는, 카메라 자체검정을 통해 내부 표정요소를 정확히 계산해내야 한다. 이를 위해서는 적절한 검정 대상지의 구성 및 촬영계획이 선행되어야 한다. 본 연구에서는 지상기준점 수, 사진의 수, 기준점의 차원(2차원 및 3차원)등의 조건에 따른 카메라 자체 검정 정확도에 대하여 분석하였다. 실험 결과, 근거리 사진측량을 위한 자체검정 대상지 구축 시 수직사진을 포함하는 3장 이상의 사진으로 안정된 정확도를 얻을 수 있음을 알 수 있었고, 3차원 복원을 목적으로 하는 경우, 평면상의 지상기준점 10점으로도 높은 정회도의 결과를 얻을 수 있음을 알 수 있었다.

• 한국자동차공학회논문집
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• 제16권1호
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• pp.134-143
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• 2008

The hardware scatters as well as the engine parameters calibration have strong influences on exhaust emissions in recent diesel engines. In this research DoE(Design of Experiments) optimizations were done to study the possibility of minimizing the emission deviations caused by flow rate scatters of the injectors. It has been shown that the optimization of engine calibration, which minimizes the emission deviations, is feasible by establishing a target function representing the emission deviations for test results of maximum, mean and minimum flow rate injectors. It has also been shown that optimization of both emission deviations and emission level is possible by sequential DoE optimizations of the target functions representing the emission level and the emission deviations respectively with the appropriate boundary limits.

• International Journal of Aeronautical and Space Sciences
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• 제17권2호
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• pp.253-259
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• 2016

The typical method for performing an absolute radiometric calibration of a Synthetic Aperture Radar (SAR) System is to analyze its response, without interference, to a target with a known Radar Cross Section (RCS). To minimize interference, an error-free calibration site for a Corner Reflector (CR) is required on a wide and flat plain or on an area without disturbance sources (such as ground objects). However, in reality, due to expense and lack of availability for long periods, it is difficult to identify such a site. An alternative solution is the use of a Triangular Trihedral Corner Reflector (TTCR) site, with a surrounding protection wall consisting of berms and a hollow. It is possible in this scenario, to create the minimum criteria for an effectively error-free site involving a conventional object-tip reflection applied to all beams. Sidelobe interference by the berm is considered to be the major disturbance factor. Total interference, including an object-tip reflection and a sidelobe interference, is analyzed experimentally with SAR images. The results provide a new guideline for the minimum criteria of TTCR site design that require, at least, the removal of all ground objects within the fifth sidelobe.

• 한국통신학회논문지
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• 제21권7호
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• pp.1820-1832
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• 1996

본 논문에서는 디지탈 이동채널환경에서 적용이 가능한 두가지 형태의 파일롯 톤을 이용한 반송파 동기방식을 제시하고 이에 대한 성능을 비교 분석하였다. 이동채널환경에서는 다중경로에 의한 페이딩으로 인하여 수신신호의 진폭 요동과 불규칙한 위상변화로 반송파동기 및 수신기의 성능이 급격히 열화된다. 이러한 페이딩채널에 적용가능한 반송파동기방식으로 TCT(Tone Calibration Technique)와 DTCT(Dual Tone Calibration Technique)를 제시하고 Rayleigy 와 Rician 페이딩하에서 성능을 분석하였다. 또한 파일롯 대 신호전력비와 신호대 파일롯필터 대역비와 같은 주요한 설계파라메타에 대하여 BER 성능을 구함으로써 두가지 방식에 대한 심도있는 고찰과 시스템 최적화를 수행하였다.

• 한국게임학회 논문지
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• 제19권5호
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• pp.39-52
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• 2019

최근 체감형 스포츠 게임은 시각적 자극 통한 콘텐츠 몰입을 위해 다양한 연구가 진행되고 있다. 그 중 미디어 콘텐츠의 다면 영상 기술은 넓은 시야에 영상을 투사하여 몰입시키기에 적절하지만 캘리브레이션과 시야에 맞는 매핑 작업을 따로 거쳐야한다는 어려움이 있다. 본 논문은 누구나 쉽게 적용 가능한 캘리브레이션 매핑 기술을 개발하고, CAVE 형태의 체감형 필드아처리 게임 공간에 적용한다. 그 결과 콘텐츠의 해상도를 유지하고 왜곡 없는 영상을 통해 체험자에게 공간감 제공이 가능하다는 것을 확인하였다. 본 논문에서 개발한 기술은 소방 훈련 콘텐츠와 같이 높은 몰입이 필요한 훈련 및 교육 분야에도 활용 가능할 것으로 기대한다.

• 한국CDE학회논문집
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• 제9권4호
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• pp.397-405
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• 2004

Texture mapping is the process of covering 3D models with texture images in order to increase the visual realism of the models. For proper mapping the coordinates of texture images need to coincide with those of the 3D models. When projective images from the camera are used as texture images, the texture image coordinates are defined by a camera calibration method. The texture image coordinates are determined by the relation between the coordinate systems of the camera image and the 3D object. With the projective camera images, the distortion effect caused by the camera lenses should be compensated in order to get accurate texture coordinates. The distortion effect problem has been dealt with iterative methods, where the camera calibration coefficients are computed first without considering the distortion effect and then modified properly. The methods not only cause to change the position of the camera perspective line in the image plane, but also require more control points. In this paper, a new iterative method is suggested for reducing the error by fixing the principal points in the image plane. The method considers the image distortion effect independently and fixes the values of correction coefficients, with which the distortion coefficients can be computed with fewer control points. It is shown that the camera distortion effects are compensated with fewer numbers of control points than the previous methods and the projective texture mapping results in more realistic image.