• 전기학회논문지
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• 제61권4호
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• pp.643-649
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• 2012

The diagnosis technique of stator winding faults based on Motor Current Signature Analysis(MCSA) was suggested. Park's vector pattern, the circle that is drawn by d-q transformed currents($i_d$, $i_q$), is widely used for stator winding faults detection. The current Distortion Ratio(DR), defined by the ratio of max axis and min axis of ellipse of Park's vector's pattern, was more simple and powerful method than the Park's vector pattern. In this study, a calculation method of distortion ratio of Park's vector pattern was suggested for auto diagnosis of stator winding short fault and usefulness of suggested calculation method of distortion ratio was verified through simulation using LabVIEW program.

• 전기학회논문지P
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• 제57권2호
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• pp.160-163
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• 2008

In this paper, an auto-diagnosis method of the stator winding fault for small induction motor is suggested. 3-phase stator currents are sampled, filtered, and transformed with Park's vector transformation. After then Park's vector patterns are obtained. To detect the stator winding fault automatically, a distortion ratio is newly defined and compared with the one of healthy motor, and the threshold levels of distortion ratio are suggested. The 2-turn, 4-turn, 8-turn winding fault are tested with no load, 25%, 50%, 75%, and 100% rated load. The distortion ratio of the Park's vector patterns are increased as the increase of the faulted turns, but are same as the increase of the load.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.2075-2076
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• 2011

The stator winding faults diagnosis technique based on MCSA is as follows. Firstly, collecting the 3 phase motor currents, that signal is transformed by (d-q transform, $i_d$, $i_q$). Park's vector pattern, the circle that is down by d-q transformed currents($i_d$, $i_q$). The circle is widely used for stator winding faults detection. The current distortion ratio(DR), defined by the ratio of max-axis and min-axis of ellipse of Park's vector's pattern. In this study, distortion ratio of Park's vector pattern is suggested for Auto diagnosis of stator winding short fault and usefulness of distortion ratio is verified through simulation using LabVIEW program.

• 반도체디스플레이기술학회지
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• 제20권3호
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• pp.18-21
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• 2021

This paper analyzes the distortion correction of the in the micro DMD(digital micro mirror device) projector system using 0.25 or less optical throwing distance ratio. The distortion of projected image occurs depending on the performance of the optical lens, the installation location of the projection system, and the tilt of the screen. This study analyzed the physical tilt values influencing of the distortion of projected image, removed the tilt distortion of throwing distance ratio optical lens, and adjusted the distortion image by the simulation of calibration displacements. The results of this study demonstrated within 5% TV distortion reference. Moreover, the correction method reduced the pin-distortion correction of projection system.

• 한국방사선학회논문지
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• 제10권5호
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• pp.359-365
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• 2016

투시조영촬영은 인체 내부의 조직이나 장기를 검사할 때 시행하며 특히 척추 질환의 진단 및 시술에 사용된다. 영상증배관(image intensifier tube)을 사용하는 투시조영 촬영장비는 영상에서 중심부보다 주변부에 왜곡이 나타난다. 본 연구에서는 교정 알고리즘을 적용하여 교정전과 교정후의 수직길이비 왜곡비율과 대각길이비의 왜곡비율을 측정하였다. 수직길이비의 측정결과는 교정후의 표준편차가 교정전보다 0.04감소하였고 대각길이비의 측정결과는 교정후의 표준편차가 교정전보다 0.06감소하여 교정 후 투시영상의 왜곡이 감소되었다. 향후 교정 알고리즘의 적용과 성능향상을 통해서 영상왜곡을 감소시키면 요추디스크의 치료를 위한 수핵감압술시 요추천자의 정확한 위치를 찾는데 도움을 줄 것으로 사료된다.

• 대한치과보철학회지
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• 제26권1호
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• pp.31-49
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• 1988

This study was performed to investigate the sound distortion following the alternation of the palatal plate thickness, for this study, 3 subjects who were born in Seoul and spoke Seoul dialect were recruited from K university male student population. First, their sounds of /아(a)/, 어(e)/, 오(o)/, 우(u)/, 으($\.{+}$), 이(i)/,에(e)/ without inserting plate were recorded , and then the sounds with palatal plates of different thickness were recorded, respectively. The palatal plates was constructed to cover the alveolar & palatal surfaces of the maxilla with an approximate thickness of 1.0mm, 2.5mm, and thickness of 2.5mm over the alveolar ridge & 1.0mm elsewhere and, named B, C, D-type, in succession. Series of analysis were administered through Computer (16 bit IBM PC/AT) at analyze the sound distortions. These experiments were analyzed by the LPC, Log Area Ratio. The findings led to the following conclusions: 1. Sound distortions were relatively minute in each condition and informations, however, /이(i)/ was the most distorted vowel in all conditions. 2. By and large, sound distortion was large in C, D-types. However, there was no correlation of the distortion rate on the 3 informants, and all tested vowels. 3. It was similar to LPC, Log Area Ratio distortion rates. 4. It was found that the sound distortion wit]1 plate inserted was verified to the numeric value with LPC and Log Area Ratio method.

• 펄프종이기술
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• 제31권5호
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• pp.73-85
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• 1999

Yield and fracture are separated in the tensile failure of paper. Failure in the machine direction of photocopy paper is contrasted with failure in the cross-machine direction . The ratios of distortion (shape change) to dilatation (volume change) for individual elements at yield and fracture are described. The ratios of distortion to dilatation are measured and compared to predicted values of the strain energy density theory. To evaluate the effect of the angle from the principal material direction on the strain energy density theory. To evaluate the effect of the angle from the principal material direction on the strain energy density factor, samples are prepared from machine direction to cross-machine direction in 15 degree intervals. the strain energy density of individual elements are obtained by the integration of stress from finite element analysis with elastic plus plastic strain energy density theory. Poison's ratio and the angle from the principal material direction have a great effect ion the ratio fo distortion to dilatation in paper. During the yield condition, distortion prevails over dilatation . At fracture, dilatation is at a maximum.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2003년도 춘계 학술발표회논문집
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• pp.238-246
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• 2003

By using simulated ground motions, which is sum of earthquake signals and noise, we measured the distortion of response spectra due to noise. We found that the distortion is more closely related to the signal-to-noise (S/N) ratio of root-mean-square (RMS) measurement than that of conventional peak measurement. Given a S/M ratio, the distortion of absolute acceleration response spectra is independent on the earthquake magnitude, while that of relative displacement response spectra has a strong dependence on the earthquake magnitude. This means that, when we calculate response spectra from time histories, we can efficiently predict the distortion of acceleration response spectra simply by measuring the RMS SJN ratios, or the distortion of displacement response spectra by combining the RMS S/N ratios and the earthquake magnitudes.

• 한국정밀공학회지
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• 제24권8호통권197호
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• pp.74-80
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• 2007

The distortion of printed pattern is frequently observed in gravure offset printing process, which can be a serious problem in printing process for printed electronics. The mechanism of pattern distortion is studied and the factors which affect the amount and shape of distortion are found using FEM. The amount and shape of distortion is influenced by material properties of the roller, thickness of roller, applied load, and so on. As the printing pressure increases and Possion ratio increases, the degree of the image distortion increases. And the increase of the thickness of rubber roller brings a large distortion of image, too. In some cases, the distortion of printed pattern can reach a few hundred micromillimeters. The comparison of the experiment result and the simulation result shows good agreement in their quantitative tendency.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2017년도 제48회 춘계학술대회논문집
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• pp.180-187
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• 2017

항공기 엔진 지상 성능시험을 위한 15만 파운드 급 Test 설비를 구축하기 위해 Test Cell Type, Cell Flow, Cell Bypass Ratio, Approach Velocity, Cell Depression, Front Cell Distortion, Noise 및 Vibration 등의 주요 설계 목표를 설정 하였고, 설비 완공 후 최종 성능검사를 통해 목표 값을 충족하는 성능 데이터를 획득할 수 있었다.