• 한국음향학회지
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• 제26권4호
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• pp.173-181
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• 2007

본 논문에서는 음향 스펙트로그램을 이용하여 수중 이동표적의 위치를 추정하기 위한 방법을 연구하였다. 주파수와 시간의 2차원 평면으로 표현되는 스펙트로그램은 수중 운동체의 이동 정보를 제공한다. 음원과 수신 센서간의 거리가 충분히 멀 경우 스펙트로그램의 넓은 주파수에 걸쳐 발생하는 줄무늬들은 해수면 및 해저면에 의해 반사된 모드간의 간섭을 의미하고, 이때 최대 음압이 발생하는 줄무늬의 기울기는 음향 도파관 불변인자 ${\beta}$와 표적과 센서간의 거리에 의해 영향을 받는다. 2개 이상의 센서를 사용하여 이동하는 선박의 광대역 방사 소음을 측정한 경우 스펙트로그램에 나타나는 최대 음압이 발생하는 줄무늬의 기울기와 줄무늬가 주파수축에서 천이된 비율이 표적과 센서간의 거리에 따라 각각 다르게 나타난다. 두개의 센서를 두 정점으로 가정하여 표적에 이르는 거리의 비가 일정한 값을 가지면서 운동하는 점의 자취인 아폴로니오스의 원을 형성하고, 3개의 센서를 사용할 경우 두 개의 원이 서로 교점을 형성하는데, 이 교점의 좌표를 표적의 위치라 추정한다. 제안된 위치 추정 기법의 성능을 평가하기 위해 음파전달 프로그램을 이용한 시뮬레이션을 수행하였다.

• 대한물리치료과학회지
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• 제15권1호
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• pp.1-9
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• 2008

Background and Purpose : This study serves the purpose to present the effective way on back pain therapy for women during their pregnancy by comparing and analyzing the effects influencing on pain index, limits on daily life, and diminution of lumbar curve, when having treated for 6 weeks, dividing into therapy group, applied by decompression therapy on spine without unnecessary effects on the pregnant women and their fetus and the existent general physiotherapy group, applied on diminution of their back pain. Subject & methods : We made impregnate women of 30(25${\sim}$34years), as the subject of this study, who understood, and agreed with, this study, among pregnant women who were diagnosed as back pain. Pain intensity, limit index on daily life, and lumbar curve test, prior to experiment was implemented as paired t－test, comparison of the difference of average by each group before and after experiment was analysed as independent t－test, and statistical examination level was set up as 0.05. Results : The difference of average of pain and limit on daily life between the group, SDTG(spinal decompression therapy group), and the group, GPTG(general physical therapy group), before and after experiment was diminished as much as 44.4% and 16.79% each after completed 6 weeks' experiment, limit on daily life in both groups showed as much as 37.2% and 21.5% each, in the end, they statistically showed conspicuous difference(p<.05). Comparison of lumbar curves between both groups, SDTG and GPTG, before and after experiment, were diminished from -23.13${\pm}$4.85 to -15.66${\pm}$3.71, and there was no remarkable difference(p<.05). Conclusion : As, in this study, decompression therapy is more effective than general physical therapy with pregnancy low back pain in pain, limitation of daily life, lumbar curve.

• 한국콘텐츠학회논문지
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• 제9권10호
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• pp.13-21
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• 2009

본 논문에서는 정확한 얼굴 영역 검출을 위한 영상화질 향상에 대한 연구를 수행하였다. 일반적인 인식시스템에서는 입력되는 모든 영상에 고정된 영상처리 과정을 수행한다. 고정된 영상처리 필터를 사용하는 방법을 다양한 환경 조건에서 획득된 얼굴 영상에 적용하게 되면, 정확한 얼굴영역을 검출할 수 없게 될 것이다. 복잡한 배경과 조명이 포함된 영상으로부터 검출에 적합한 영상으로 구성하기 위하여, 본 논문에서는 부-윈도우를 기반으로 하는 카테고리에 따른 영상 향상 방법을 제안한다. 처리를 위한 영상이 획득되었을 때, 영상의 부-윈도우로부터 평균값을 계산하고, 이를 기 구성된 카테고리와 비교하여 입력영상에 적용 가능한 영상처리 방법을 선택적으로 적용하는 처리를 수행한다. 얼굴영역을 검출한 결과 히스토그램 평활화, 감마변환등의 방법을 전체영상에 적용한 결과와, 제안된 방법을 적용하여 추출한 영상들로부터 얼굴영상 등록을 통한 검출률을 비교한 결과, 현저히 향상된 등록 결과를 획득할 수 있었다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권5호
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• pp.2156-2170
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• 2020

This paper presents a fire detection algorithm with a minimal false detection rate, intended for a thermal imaging surveillance environment, whose properties vary depending on temporal conditions of day or night and environmental changes. This algorithm was designed to minimize the false detection alarm rate while ensuring a high detection rate, as required in fire detection applications. It was necessary to reduce false fire detections due to non-flame elements occurring when existing fixed threshold-based fire detection methods were applied. To this end, adaptive flame thresholds that varied depending on the characteristics of input images, as well as the center of gravity of the heat-source and hot-source regions, were analyzed in an attempt to minimize such non-flame elements in the phase of selecting flame candidate blocks. Also, to remove any false detection elements caused by camera shaking, one of the most frequently raised issues at outdoor sites, preliminary decision thresholds were adaptively set to the motion pixel ratio of input images to maximize the accuracy of the preliminary decision. Finally, in addition to the preliminary decision results, the texture correlation and intensity of the flame candidate blocks were averaged for a specific period of time and tested for their conformity with the fire decision conditions before making the final decision. To verify the fire detection performance of the proposed algorithm, a total of ten test videos were subjected to computer simulation. As a result, the fire detection accuracy of the proposed algorithm was determined to be 94.24%, with minimum false detection, demonstrating its improved performance and practicality compared to previous fixed threshold-based algorithms.

• Journal of Radiation Protection and Research
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• 제36권1호
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• pp.16-23
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• 2011

보다 정확한 우라늄 농축도 분석은 핵물질 관리를 위하여 중요하다. 본 연구에서는 감마선을 이용한 우라늄 농축도 분석에서 시료와 검출기 사이에 차폐체가 있는 경우와 측정시간 변화에 따른 분석결과에 대한 정확성 평가 및 오차분석을 수행하였다. 우라늄 농축도를 분석하기 위하여 FRAM (Fixed energy Response function Analysis with Multiple efficiencies)을 이용하였다. FRAM에 의한 분석결과의 정확성은 화학 분석 결과와의 비교를 통해 평가되었다. 연구결과 선원과 검출기사이에 차폐체가 존재할 경우 차폐체의 두께변화에 따른 감마선의 세기는 지수함수 형태로 감소하며 감마선에너지 피이크의 반치폭 (FWHM : Full Width at Half Maximum)은 차폐체의 두께에 영향을 거의 받지 않는 것을 보였다. 따라서 시료와 검출기 사이에 차폐체가 있는 경우의 우라늄 농축도 분석에서 FRAM을 이용한 감마선분광 분석은 유용하게 활용될 수 있다. 본 연구 결과는 차폐체 안에 우라늄이 있는 경우 핵물질 분석에 기여할 수 있을 것이 기대된다.

• Earthquakes and Structures
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• 제13권3호
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• pp.267-277
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• 2017

Base-isolation is now being adopted as a retrofitting strategy to improve seismic behaviour of reinforced concrete (r.c.) framed structures subjected to far-fault earthquakes. However, the increase in deformability of a base-isolated framed building may lead to amplification in the structural response under the long-duration horizontal pulses of high-magnitude near-fault earthquakes, which can become critical once the strength level of a fire-weakened r.c. superstructure is reduced. The aim of the present work is to investigate the nonlinear seismic response of fire-damaged r.c. framed structures retrofitted by base-isolation. For this purpose, a five-storey r.c. framed building primarily designed (as fixed-base) in compliance with a former Italian seismic code for a medium-risk zone, is to be retrofitted by the insertion of elastomeric bearings to meet the requirements of the current Italian code in a high-risk seismic zone. The nonlinear seismic response of the original (fixed-base) and retrofitted (base-isolated) test structures in a no fire situation are compared with those in the event of fire in the superstructure, where parametric temperature-time curves are defined at the first level, the first two and the upper levels. A lumped plasticity model describes the inelastic behaviour of the fire-damaged r.c. frame members, while a nonlinear force-displacement law is adopted for the elastomeric bearings. The average root-mean-square deviation of the observed spectrum from the target design spectrum together with a suitable intensity measure are chosen to select and scale near- and far-fault earthquakes on the basis of the design hypotheses adopted.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2004년도 유체기계 연구개발 발표회 논문집
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• pp.140-150
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• 2004

In this study, the effect of relative position of the blade for the fixed vane has been investigated on blade surface heat transfer. The experiments were conducted in a low speed stationary annular cascade, and heat transfer of blade was examined for six positions within a pitch. Turbine test section has one stage composed of sixteen guide vanes and blades. The chord length of the tested blade is 150 mm and the mean tip clearance of the blade having flat tip is about $2.5\%$ of the blade chord. For the detailed mass transfer measurements on the blade surfaces, a naphthalene sublimation technique was used. The inlet flow Reynolds number is fixed to $1.5{\times}10^5$. Complex heat transfer characteristics are observed on the blade surface due to various flow characteristics, such as separation bubble, relaminarization, transition to turbulence and leakage vortices. The distributions of velocity and turbulence intensity change significantly with the relative position due to the blockage effect of the blade. This causes the variation of heat transfer patterns on the blade surface. The results show that the flow near the leading edge get highly disturbed and deflected toward the either side of the blade when the blade leading edge is positioned close to the trailing edge of the vane. Therefore, separation bubble disappears on the pressure side and overall heat transfer on the relaminarization region is increased. But, due to reduced tip gap flow at the upstream region, the effect of leakage flow on the upstream region of the blade surface is weakened. Thus, the heat transfer characteristics significantly change with the blade positions.

• 한국표면공학회지
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• 제41권3호
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• pp.83-87
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• 2008

This study described the effects of RF power, DC bias voltage, chamber pressure and gas mixing ratio on the etch rates of TiN thin film and selectivity of TiN thin film to $SiO_2$ with $BCl_3$/Ar gas mixture. When the gas mixing ratio was $BCl_3$(20%)/Ar(80%) with other conditions were fixed, the maximum etch rate of TiN thin film was 170.6 nm/min. When the DC bias voltage increased from -50 V to -200 V, the etch rate of TiN thin film increased from 15 nm/min to 452 nm/min. As the RF power increased and chamber pressure decreased, the etch rate of TiN thin film showed an increasing tendency. When the gas mixing ratio was $BCl_3$(20%)/Ar(80%) under others conditions were fixed, the intensity of optical emission spectra from radical or ion such as Ar(750.4 nm), $Cl^+$(481.9 nm) and $Cl^{2+}$(460.8 nm) was highest. The TiN thin film was effectively removed by the chemically assisted physical etching in $BCl_3$/Ar ICP plasma.

• Journal of Photoscience
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• 제9권2호
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• pp.430-432
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• 2002

The changes in expression of copper-zinc superoxide dismutase (CuZn-SOD), manganese superoxide dismutase (Mn-SOD) and glutathione peroxidase (GPX) in light-damaged rat retinas were examined. Sprague-Dawley rats (male, 6-weeks-old) were maintained on a cyclic photoperiod (12 hours light and 12 hours darkness) for 2 weeks. The illumination intensity during the light period was 80 lux. To induce light damage to the retina, a high-intensity illumination (3000-lux) was applied to the animals for 24 hours. After light exposure, the animals were returned to cyclic lighting. Eyes were enucleated 12 and 24 hours after light exposure started or 1,3, and 7 days after light exposure ended. Eyes were fixed and embedded in paraffin wax. Tissues were cut into 4${\mu}{\textrm}{m}$-thick sections. Sections were immunostained using antibody against CuZn-SOD, Mn-SOD, GPX and 8-hydroxy-deoxyguanocine (8-OHdG) as oxidative stress marker. 8-OHdG was observed in the outer nuclear layer (ONL) and retinal pigment epithelium (RPE) during light exposure. In light-damaged retinas CuZn-SOD labeling was up regulated in the ONL and RPE. Mn-SOD labeling was up regulated in rod inner segments (RIS) during light exposure and that in the RPE was up regulated after exposure. GPX labeling was observed in rod outer segments (ROS) during light exposure. GPX labeling was also observed in the RPE during and after light exposure. All three enzymes were observed in the outer retina, which suffered light damage, but occurred in defferent layers except within the RPE, in which case all three were expressed. These enzymes may play complementary roles as protective factors in light-damaged retinas.

• 감성과학
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• 제15권2호
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• pp.231-238
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• 2012

본 연구는 하나의 감각으로 인해 다른 영역의 감각을 불러일으키는 공감각 현상을 기초로 하여 사운드에서 컬러이미지를 유추하여 생성하는 응용 시스템의 구현을 최종 목표로 한다. 이를 위해 사운드의 특징정보인 기본주파수(F0, Fundamental Frequency)에서 음계(Scale) 및 옥타브(Octave) 성분을 추출한 후, HSI 컬러모델인 색상(Hue), 명도(Intensity) 성분에 각각 매핑한다. 본 논문에서 채도(saturation)값은 고정된 값을 사용한다. 이를 다시 RGB 컬러모델로 변환한 후 최종 BMP 포맷으로 컬러 이미지를 출력한다. 본 연구에서 제시한 사운드-컬러이미지 변환 방법을 토대로 기본 변환 시스템을 구현해 본 결과, 기본주파수에서 추출된 음계 및 옥타브 성분의 변화에 따라 색상 및 명도가 상이한 다양한 컬러가 나오는 것을 확인할 수 있었다. 또한 하드웨어적 구현을 위해 TMS320C6713 DSP Board에 포팅하여 실험한 결과 제안된 시스템의 시뮬레이션 결과와 동일한 컬러 이미지가 출력됨을 확인하였다.