• Journal of the Optical Society of Korea
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• 제15권1호
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• pp.38-43
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• 2011

We have developed a simple model of a bright-room contrast ratio (BRCR) measurement system for plasma display panels (PDPs) adopting a contrast enhancement film (CEF) by using an illumination design tool. Only four model parameters were used, namely, total ambient illumination power delivered by fluorescent lamps, a panel scattering rate, illuminance of PDP white patterns, and the absorption coefficient of a color adjusting film. These parameters were determined by simple optical measurements and matching simulations. The proposed model was employed to predict the BRCR values of four different CEF samples, and the simulated ones were found to be in agreement with measured ones within about 10% relative-error.

• 전기학회논문지P
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• 제62권2호
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• pp.90-94
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• 2013

In this paper, we propose a new algorithm to improve the contrast ratio, to preserve information of bright regions and to maintain the color of backlight image that appears with a great relative contrast. Backlight images of the natural environment have characteristics for difference of local brightness; the overall image contrast improvement is not easy. To improve the contrast of the backlight images, MSR (Multi-Scale Retinex) algorithm using the existing multi-scale Gaussian filter is applied. However, existing multi-scale Gaussian filter involves color distortion and information loss of bright regions due to excessive contrast enhancement and noise because of the brightness improvement of dark regions. Moreover, it also increases computational complexity due to the use of multi-scale Gaussian filter. In order to solve these problems, a linear MSR is performed that reduces the amount of computation from the HSV color space preventing the color distortion and information loss due to excessive contrast enhancement. It can also remove the noise of the dark regions which is occurred due to the improved contrast through edge preserving filter. Through experimental evaluation of the average color difference comparison of CIELAB color space and the visual assessment, we have confirmed excellent performance of the proposed algorithm compared to conventional MSR algorithm.

• 대한의용생체공학회:의공학회지
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• 제18권2호
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• pp.113-120
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• 1997

This paper presents an optimal design for the SPECT reconstruction filter, based on a physical limit of SPECT lesion detection capability. To increase the performance of the filter on lesion detectability, the filter design was focused on increasing the local SyW ratio of a threshold lesion, that was determined by minimum detectable lesion size (MDU) from SPECT lesion detectabllity contrast-detail curve. The proposed filter showed flexible window characteristics of resolution recovery and noise smoothing for MDLSs in the resolution-limited and photon-limited regions, respectively, compennting for the relative impact of the main limitation factors on threshold detectability. The simulated results showed good adaptability of the proposed filter to the changes in physical parameters of photon counts, object contrast, and detector system resolution.

• 치위생과학회지
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• 제7권1호
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• pp.9-12
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• 2007

마, 꿀풀 추출물의 용매 분획별 구강병인균에 대한 항균 및 항우식 효과를 알아본 결과 다음과 같은 결과를 얻었다. S. mutans에 대한 마, 꿀풀 헥산 추출물의 상대성장률과 산 생성 억제 및 GTase 활성 저해효과을 알아본 결과, 마 헥산 추출물의 0.25 mg/ml 농도에서 100%, 꿀풀헥산 추출물의 0.5 mg/ml 농도에서 100% 성장을 억제하였다. 따라서 농도가 증가함에 따라 성장이 억제되는 것을 볼 수 있었다. 2.0 mg/ml 농도에서 마가 pH 7.2, 꿀풀이 pH 7.0로 나타나 pH 5.6, pH 5.2인 대조군과 비교하여 볼 때 마, 꿀풀 헥산 추출물을 첨가물이 산 생성을 억제하여 중성으로 보여주고 있으며, GTase 활성 저해효과는 마와 꿀풀의 헥산 추출물의 2.0 mg/ml농도에서 35%, 25%로 각각 활성을 저해하였다.

• 대한산업공학회지
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• 제34권1호
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• pp.90-97
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• 2008

Wedged insoles are frequently used to reduce the pains caused by the knee arthritis or the foot overuse syndrome. The present study analyzed the effect of wedged rear-foot insoles on the foot pressure in walking. Three medially wedged insoles with three angles (5, 8 and 15") and three laterally wedged insoles with the same angles were made, and a flat insole were prepared. Ten healthy males in twenties walked in a specified line with each insole. Center of pressure (COP), relative vertical force and maximum force on anatomical areas were analyzed from the measured foot pressure data. At heel contact, medially wedged insoles significantly increased the pressure of the medial foot side (COP moved medially by 2-5 mm and maximum pressure of 1st metatarsal head increased by 110-120% relative to the flat insole), In contrast, laterally wedged insoles significantly increased the lateral side pressure (COP moved laterally by 1-5 mm and the ratio of $2^{nd}$ metatarsal head pressure to $1^{st}$ metatarsal head increased by 0.5-2.0 relative to the flat insole). At toe off, both wedged insoles significantly increased the pressure of the medial foot side (COP moved medially by 0.5-10 mm and the ratio of $1^{st}$ metatarsal head pressure to $5^{th}$ metatarsal head increased by 2.0 relative to the flat insole). Especially, the laterally wedged insoles significantly increased the relative vertical force (6-12%) of the rear-foot more than the flat insole.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 Ⅳ
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• pp.2403-2406
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• 2003

When viewing images, the relative luminance of the surround has a profound impact on the apparent contrast of the image. The dark surround causes the image elements to appear lighter than those viewed in an illuminated surround. For this reason, it is worthwhile to briefly review the general results of brightness sealing under a various viewing condition. Two of the most often cited parers on the topic of brightness scaling are Stevens-stevens and Bartleson-Breneman's function. There are, however, significant differences between the perceptual functions for simple-field and complex-field viewing. In this paper, we research the relationship between Steven's power law and Bartleson-Breneman's function. We present an appropriate brightness perception function due to TV system viewing conditions. Highlight luminance peak and absolute brightness threshold value in various adaptation levels are obtained from the proposed brightness function . Also, the luminance value of black level to produce the same contrast ratio with variety of display highlight luminance peak is obtained from the proposed brightness function.

• 한국재료학회지
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• 제25권1호
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• pp.1-8
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• 2015

This study suggested comprehensive structural characterization methods for the commercial blue light emitting diodes(LEDs). By using the Z-contrast intensity profile of Cs-corrected high-angle annular dark field scanning transmission electron microscope(HAADF-STEM) images from a commercial lateral GaN-based blue light emitting diode, we obtained important structural information on the epilayer structure of the LED, which would have been difficult to obtain by conventional analysis. This method was simple but very powerful to obtain structural and chemical information on epi-structures in a nanometer-scale resolution. One of the examples was that we could determine whether the barrier in the multi-quantum well(MQW) was GaN or InGaN. Plan-view TEM observations were performed from the commercial blue LED to characterize the threading dislocations(TDs) and the related V-pit defects. Each TD observed in the region with the total LED epilayer structure including the MQW showed V-pit defects for almost of TDs independent of the TD types: edge-, screw-, mixed TDs. The total TD density from the region with the total LED epilayer structure including the MQW was about $3.6{\times}10^8cm^{-2}$ with a relative ratio of Edge- : Screw- :Mixed-TD portion as 80%: 7%: 13%. However, in the mesa-etched region without the MQW total TD density was about $2.5{\times}10^8cm^{-2}$ with a relative ratio of Edge- : Screw- :Mixed-TD portion of 86%: 5%: 9 %. The higher TD density in the total LED epilayer structure implied new generation of TDs mostly from the MQW region.

• 복식
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• 제58권6호
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• pp.54-68
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• 2008

The purpose of this study is to investigate the effect of dot pattern size(0.8, 1.8, 2.5, 5, 8), color combination(BG/R, Y/B), area-ratio on image formation. Sets of stimulus and response scales(7 point semantic) were used as experimental materials. The stimuli were 20 color pictures manipulated with the combination of dot pattern size, color combination, and area-ratio using computer simulation. The subjects were 240 female undergraduates living in Gyeongnam-do. Image factor of the stimulus was composed of 5 different components, visibility, attractiveness, cuteness, stability and high class image. In the cuteness, color combination, dot pattern size showed independent effect. In the stability, area-ratio, dot pattern size showed independent effect. Interaction effects of color and area-ratio combination was significant on cuteness. For visibility image 8cm yellow dot/blue background, for attractiveness image BG/R coloration, for cuteness image Y/B coloration and for stability image 0.8cm yellow dot/blue background were effective. According to the variation of dot pattern size, color combination and area-ratio, it was investigated that the images for a dress wearer were expressed diversely, were shown differently in image dimensions, and could be produced to different images.

• 가정과삶의질연구
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• 제18권3호통권47호
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• pp.1-14
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• 2000

This study was to find out the status of labor division between rural husband and wife by measuring the labor time for tasks, the ratio of relative contribution toward work, and work segregation. Data used in this study were collected fro 424 persons of 212 farm households mainly cultivating rice and barley. The results of this study were as follows : 1) In the case of work directly related to farming, working hours of husband were significantly longer than those of wife during the farming and off-farming season. In contrast working hours of wife for housekeeping were significantly longer than those of husband during both seasons. 2) The ratio of relative contribution toward farming work of husband was a little higher than that of wife during farming and off-farming season. But this toward housekeeping work was less than that of wife. 3) The degree of gender segregation in farming was 0.33 during the farming season and 0.01 during the off-farming season. The kinds of work and time distribution were relatively same. The degree of gender segregation in housekeeping was 0.79 during the farming season and 0.72 during the off-farming season. These values showed inequality of work segregation in the kind of work and time distribution.

• 인터넷정보학회논문지
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• 제19권1호
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• pp.105-111
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• 2018

건축 구조물의 상대적인 변위 계측을 위하여 2메가 픽셀 Full HD(FHD) 해상도의 카메라와 디지털 영상상관(DIC, Digital Image Correlation) 플랫폼을 설계하고, 계측에 영향을 주는 영상 품질을 분석하였다. DIC 플랫폼은 Freescale사의 I.MX6를 기반으로 설계하였다. 영상 상관을 이용한 계측은 영상의 품질에 따라 계측 정밀도에 영향을 줄 수 있는데, 이러한 영상 품질 요인으로 영상의 밝기(brightness), 대조(contrast), 신호대 잡음비(SNR, Signal to Noise Ratio)를 분석하였다. 관심 영역(ROI, Region Of Interest)으로 설정한 부분에서 추출한 영상을 기준 영상으로 삼고, 일정 시간 경과 후 디지털 영상 상관(DIC)을 이용하여 기준 영상의 이동을 화소 및 부화소 단위로 추적 계산하여 변위를 측정하였다. 더불어 DIC 기반의 비접촉 원격 계측의 유효성을 파악하기 위하여 25m, 35m, 50m의 계측 거리에서, 영상 품질 요인 및 ROI 의 크기를 조정하여 측정을 하고 정밀도를 분석하였다.