• 방송공학회논문지
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• 제23권5호
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• pp.714-717
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• 2018

본 논문은 적응적 색 포화도 보상을 통한 HDR 영상 생성 기법을 제안한다. 기존의 HDR 기법은 밝기 변화에 초점이 맞추어져 있기 때문에 어두운 영역에서 밝기 향상에 따라 색이 옅어져 보이는 원인이 된다. 따라서 제안한 색 포화도 보상 기법은 HDR 영상 생성 시 밝기 변화에 따라 적응적으로 색 포화도를 보상함으로써 색 포화도가 옅어지는 문제를 해결하고 선명도를 향상할 수 있다. 다양한 형태의 영상에 대한 실험을 통해 제안한 방법이 기존 방법에 비해 HDR 영상화의 성능에서 우수함을 확인하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 D
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• pp.1382-1384
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• 1998

Electroluminescence is occurred when phosphor is located in electric field. Object of this research show new type of powder electroluminescent device (PELD) for high brightness compared with conventional PELD. New type of PELD structured as follow ITO/phosphor + dielectric/Silver paste). To investigate optical properties of PELDs, EL spectrum, CIE coordinate system, Brightness of PELDs was measured. The suitable ratio between phosphor and dielectric in new type of PELD was 7:3(phosphor:dielectric). At 200 V 400 Hz, new type of PELD which had ratio of 7:3 was 5700 cd/$m^2$.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 1998년도 학술발표회논문집
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• pp.9-11
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• 1998

A phenomenon of electroluminescent radiate as electric field applied in the phosphor, in this paper, we produced the Powder Electroluminescent Device(PELD) which was changing the structure and the thickness of phosphor and insulator for realization of the PELD with high brightness. We made PELD with structure that is WK-1(ITO film/Phosphor/Insulator/Electrode), WK-2(ITO film/Phosphor/Insulator/Electro de), WK-3(ITO film/Phosphor/Insulator/Electrode), WK-4(ITO film/Phosphor+Insulator/ Electrode). The property of the produced PELD are analyzed by measuring the spectrum which electrical and optical property, the brightness and the transferred charge density. In this result, the structure of WK-4 have good luminescence property than others, it's effective thickness is 60${\mu}{\textrm}{m}$. At 100V 400Hz, High brightness of 2700cd/m2 was performed.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송∙미디어공학회 2018년도 하계학술대회
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• pp.59-62
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• 2018

In this paper, we propose a contrast enhancement algorithm using guided image filter (GIF). The GIF is used to divide an HDR image into a base layer and a detail layer. The energy scale of base layer determinate the darkness and brightness of the image. However, the detail information in the base layer is difficult to be displayed because of the high brightness and clusters of low brightness. We propose a contrast enhancement method by adjusting the gray level of base layer by subtracting the mean value of itself. It is combined with the detail layer to preserve the detail information. Experiment results show that the proposed algorithm has better performance in detail preservation and contrast enhancement.

• 천문학회보
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• 제46권2호
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• pp.57.1-57.1
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• 2021

K-SIM (KASI-Simulation) research project is dedicated to develop new numerical techniques in order to theoretically study galaxy formation and evolution. As the first step of the K-SIM, to model tidal stripping of galaxies with a very high resolution in a fully cosmological context, we invented the Galaxy Replacement Technique (GRT) that is very efficient and fast. The high resolution allows us to accurately resolve the tidal stripping process and well describe the formation of ultra-low surface brightness features in the galaxy cluster (㎶ < 32 mag/arcsec^2), such as the intra-cluster light, shells and tidal streams. I'll introduce how the GRT is designed and which science topics in low-surface brightness regime can be visited using the GRT.

• 한국전기전자재료학회논문지
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• 제23권8호
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• pp.593-600
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• 2010

In this paper, High brightness LED (light-emitting diodes) driver IC (integrated circuit) using new current sensing circuit is proposed. This LED driver IC can provide a constant current with high current precision over a wide input voltage range. The proposed current-sensing circuit is composed of a cascode current sensor and a current comparator with only one reference voltage. This IC minimizes the voltage stress of the MOSFET (metal oxide semiconductor field effect transistor) from the maximum input voltage and has low power consumption and chip area by using simple-structured comparator and minimum bias current. To confirm the functioning and characteristics of our proposed LED driver IC, we designed a buck converter. The LED current ripple of the designed IC is in ${\pm}5%$ and a tolerance of the average LED current is lower than 2.43%. This shows much improved feature than the previous method. Also, protections for input voltage and operating temperature are designed to improve the reliability of the designed IC. Designed LED driver IC uses 1.0 ${\mu}m$ X-Fab. BiCMOS process parameters and electrical characteristics and functioning are verified by spectre (Cadence) simulation.

• 펄프종이기술
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• 제33권4호
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• pp.42-48
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• 2001

The spent liquor (BSL) obtained from alkaline sulfite-anthraquinone (AS-AQ) cooking of pine bark was applied as a deinking agent. In the ONP deinking system, although BSL removed the small size of ink particles (${\geq}$$12.5{\mu}m$), it did not improve the brightness of pulp. The brightness of pulp slightly improved when treated with BSL at 150~$180^{\circ}C$. However, the brightness of the pulp was lower than that of a commercial deinking agent (oleic acid). It seems that BSL treated with a high temperature still had a high dispersing ability on the ink particles. Intensive oxidations were introduced, and remarkable deinking effects were observed at 13kgf/$cm^2$ oxygen pressure, $160^{\circ}C$ and 2h. When BSL treated at 13kgf/$cm^2$ oxygen pressure, $170^{\circ}C$ and a time period of 30~90 min is added to the pulp, at 0.1% or lower, the deinking effect became higher than that of oleic acid. On the other hand, additional alkali treatments during the oxidation possibility as a deinking agent when oxidized. However, since the oxidized BSL still has a high dispersing ability and lower molecular weight, several modifications need to be done in the near future in order to be applied as a high quality deinking agent.

• 전자공학회논문지
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• 제51권4호
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• pp.123-130
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• 2014

TFT-LCD 영상에서 결함은 일반적으로 배경과 비교하여 밝기 차이가 큰 특징을 사용하여 검출된다. 본 논문에서는 휘도 차에 따른 결함 가능성이 높은 순으로 결함을 검출하는 순차적 결함 검출 방법을 제안한다. 제안한 방법은 배경과의 휘도 차가 큰 결함은 정확히 검출하고, 배경과의 휘도 차가 작은 결함인 한도결함도보다 신뢰있게 검출하여 과검출을 최소화할 수 있다. 실험을 통해 제안한 방법은 배경과의 휘도 차가 큰 결함뿐만 아니라 한도결함에 대해서도 우수한 검출 결과를 나타냄을 확인하였다.

• 펄프종이기술
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• 제31권1호
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• pp.1-9
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• 1999

This study was performed to investigate the deinkability of Korean old newspaper(KONP) and the properties of newsprint made from deinked pulp with some addition of virgin pulp. When the samples of composed of 50% Australian old magazine(AuOMG) and 50% KONP were compared with the samples 50% AuOMG and 50% AuONP, the yield, opacity, strength properties of the former were high, but its brightness was low. When the mixing ratio of AuOMG : AuONP : KONP was 30:20:50, the brightness and strength properties were obtained the similar or better than those obtained samples having other mixing ratio. The brightness and opacity of samples made from deinked pulp with the some addition of TMP and BKP can meet the minium qualifications of brightness and opacity specified by Japanese Industrial Standard. The samples, which DIP, TMP, and KP were mixed with the ratio of the 85:10:5 and 90:5:5, maintained higher brightness and strength comparing to the samples containing higher amount of virgin pulp. Since the newsprint samples made from KONP was not inferior to those from imported old newspaper, the more use of KONP in producing newsprint is recommended.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2006년도 PAN PACIFIC CONFERENCE vol.2
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• pp.381-386
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• 2006

Many different types of bleaching chemicals and processes have been globally used for deinked pulp. Besides chlorine-free bleaching chemicals, hydrogen peroxide, and sodium dithionite that could be used without restriction for almost all types of fibers, chlorine-containing chemicals such as chlorine dioxide and sodium hypochlorite have also used throughout the world. Even though hydrogen peroxide is commonly used in newsprint, it could not effectively increase brightness. Experimental evaluation on the possibility of using formamidine sulfinic acid (FAS), a reducing agent, for bleaching a wood-containing deinked pulp has been carried out in this study. The effect of bleaching efficiency for FAS on operational conditions and chemical concentrations compaired to hydrogen peroxide in one and two stages was studied. FAS bleaching showed higher brightness at high temperature and low consistency, and vice versa for peroxide one. Bleaching with sodium silicate and DTPA in FAS and peroxide stage showed better results than cases without them. Sodium silicate and chelant seemed minimize the influence of transition metal ions, including manganese and iron ions, which induce both bleaching agents to decompose. As a result, FAS as a reducing agent seems more effective than hydrogen peroxide for increasing brightness and reducing yellowness. FAS and FAS sequence seemed more efficient than the other two stages of bleaching sequences with regard to the best brightness level obtained. When bleaching was conducted with FAS, COD load was just about one-third compared to peroxide, and brightness stability of the bleached pulp appeared better than peroxide after UV light irradiation.