• 한국컴퓨터그래픽스학회논문지
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• 제21권3호
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• pp.27-35
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• 2015

본 연구는 전역 조명 기법 중 하나인 환경-광 가림(ambient occlusion)을 이용한 볼륨 렌더링 방법을 설명한다. 볼륨 밀도 분포를 정규 분포로 가정하여, 환경-광 가림을 불투명도 전이함수의 변경과 무관하게 실시간 가시화할 수 있다. 전처리 과정에서 각 복셀 주변의 일정 크기 영역의 평균과 표준편차를 계산하여 두고, 가시화 단계에서 근방의 불투명도를 추정하여 밝기를 계산한다. 이 논문은 본 연구자들의 기존 연구를 발전시켜 이론적 모델을 일반화하고 출력 영상의 화질을 향상시킨다. 구체적으로 다양한 형태의 불투명도 전이함수를 사용할 수 있는 계산 모델을 제안한다. 그리고 영역의 크기를 다양하게 통계량을 생성하여 근처의 물체에 더 높은 가중치를 부여할 수 있도록 하였다. 최종적으로 환경-광 가림 효과와 지역 조명 효과를 혼합하여, 더 현실감 있는 화질의 볼륨 가시화 영상을 실시간으로 생성할 수 있다.

• 조명전기설비학회논문지
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• 제22권11호
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• pp.1-8
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• 2008

In this paper, the optical properties of the 54[W] LED module have confirmed by changing the angles of LED modules for street light applications. The angle of LED module changed from the $0[^{\circ}]$ to $60[^{\circ}]$ varying by $20[^{\circ}]$ as horizontal direction ${\ominus}_1$. Morever, the angle of LED module changed from the $0[^{\circ}]$ to $15[^{\circ}]$ varying by $5[^{\circ}]$ as vertical direction ${\ominus}_2$. As a result of simulation, the average illumination was about 17[lux] and the overall illuminance uniformity was 0.29 for a 10.39[m] long and 6[m] wide illuminance area at height of 6[m], which is acceptable for street lighting illumination in the Illuminating Engineering Society(IES) standard.

• 한국전기전자재료학회논문지
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• 제28권4호
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• pp.271-275
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• 2015

The floodlighting assists the pilot in taxiing the aircraft into and out of the final parking position and provide lighting suitable for passenger to embark and debark and for personnel to load and unload cargo. It is composed of sodium lamps which is consuming high energy. It needs to develop a dedicated LED lamp to replace the existing lamps. In this paper, We propose a suitable asymmetric angle of LED lamps to avoid a pilot's glare and to meet the standard illumination. For this, we analyze asymmetric angle of sodium lamps which are using in airport and confirm whether the illumination distribution and glare index meet the relating standards by using simulation method. Also, we study the needs of asymmetric characteristics of LED ramp by simulating the LED lamps with and without asymmetric characteristics of ramp respectively. With the simulation result, finally we propose the best asymmetric angle of LED lamp to meet the average illumination standard, and avoid a pilot's glare.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2023년도 추계학술발표대회
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• pp.637-640
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• 2023

This paper presents multimodal image fusion with human pose for detecting abnormal human behaviors in low illumination conditions. Detecting human behaviors in low illumination conditions is challenging due to its limited visibility of the objects of interest in the scene. Multimodal image fusion simultaneously combines visual information in the visible spectrum and thermal radiation information in the long-wave infrared spectrum. We propose an abnormal event detection scheme based on the multimodal fused image and the human poses using the keypoints to characterize the action of the human body. Our method assumes that human behaviors are well correlated to body keypoints such as shoulders, elbows, wrists, hips. In detail, we extracted the human keypoint coordinates from human targets in multimodal fused videos. The coordinate values are used as inputs to train a multilayer perceptron network to classify human behaviors as normal or abnormal. Our experiment demonstrates a significant result on multimodal imaging dataset. The proposed model can capture the complex distribution pattern for both normal and abnormal behaviors.

• 한국멀티미디어학회논문지
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• 제19권2호
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• pp.233-239
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• 2016

Color enhancement basically deals with color manipulation in digital images. Recently, the technique has become widely used as a result of the increasing use of digital cameras. Retinex-based colorenhancement algorithms are a popular technique. In this paper, retinex with bilateral filtering is proposed to improve the quality of poorly illuminated images. Generally, it consists of three main steps: first, a retinex-based algorithm with color restoration; second, transformation mapping using histogram matching; and finally, smoothing the image using a bilateral filter. The experimental results demonstrate that the proposed method can successfully enhance image contrast while avoiding the halo effect and maintaining the color distribution in the image.

• 대한안전경영과학회지
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• 제12권1호
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• pp.43-50
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• 2010

The purpose of this study is to propose a simulation approach which compares lighting quality of each luminaire type for small urban park users' safety. For improving illumination quality, lighting intensity distribution of a luminaire is one of the important factors and it is also important to set the luminaire to a proper position. To achieve the best plan for illumination, it is most important to communicate the plan with designers of park and professional engineers in depth and the communication continues from the beginning of the plan.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.1427-1429
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• 2008

In this paper, an illumination system design using two lamps was proposed to improve the brightness of the projector. The proposal is based on the results from optical simulation. The prism array was applied to maintain the same optical properties, such as brightness distribution for the divergence angle and the composed beam size of the system. These were compared to those of the one UHP lamp system. The brightness of the two-lamp system, having a panel size of 0.74" and an f/2.9, increased by a factor of 1.7 when compared to the brightness of one UHP lamp system.

• KIEAE Journal
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• 제6권4호
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• pp.51-56
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• 2006

As tourist and cultural city, Chungju city struggles to exploit the new tourism resources including lighting scenic spots. This study aims to analyze the present lighting situations and suggest the alternatives for improving outdoor lightings of Hoamji Park - one of the most famous landmark in Chungju city. For the purpose, field surveys and experiments were performed on selected settings. Illumination levels were measured to compare with the KS standard by using MINOLTA T-10 instruments and some findings were discussed. As a result, some alternatives to improve the park's night images including new lighting concept, lighting fixtures and installations were suggested.

• 한국분무공학회지
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• 제11권3호
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• pp.131-139
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• 2006

An experimental study was performed to investigate the liquid breakup and atomization characteristics in electrohydrodynamic atomization according to the changing of experimental parameters such as nozzle size, fluid flow, and electrical intensity. An original electrohydrodynamic atomizer equipment was designed and manufactured for the analysis of spray visualization and the exploration of relationship between applied power and the behavior of liquid atomization. The image processing technique by using the back-illumination method was applied to visualize the distilled liquid breakup process and to examine the variation of the droplet size distribution. The results show that the spray modes of electrohydrodynamic atomization are closelyconnected by the strength of the electric stresses at the surface of the liquid film and the kinetic energy of the liquid jet leaving the needle tip.

• 조명전기설비학회논문지
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• 제15권2호
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• pp.7-12
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• 2001

본 논문에서는 광학설계프로그램을 이용하여 조명에 응용되는 LED 광원의 광학적 배치에 따른 특성 변화에 관한 연구를 하였다. 여러 유형별 시뮬레이션을 하기에 앞서 신뢰할 수 있는 기준광원을 만들었으며, 이를 이용하여 형태별 기본 배치와 각도별 기본 배치, 간격별 기본 배치의 3가지 유형별로 나누어 시뮬레이션을하여 그 변화값을 예측하였다. 그리고 안정적인 광출력 특성 및 원하는 광색을 얻기 위해서 고휘도 RGB LED의 전기적·광학적 특성을 고려한 광색 가변회로를 구성하였다.