• Journal of KIISE:Computer Systems and Theory
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• v.32 no.3
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• pp.133-147
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• 2005

Various types of ray-tracing methods are used to predict the quantity measures of radiation illumination, the uniformity of illumination, radiation performance of LCD BLU(Hack-Light Unit). The uniformity of radiation illumination is one of the most important design factor of BLU and is usually controlled by the diffusive-ink pattern printed on the bottom of light-guide panel of BLU. Therefore it is desirable to produce an improved (ideally, the optimal) ink pattern to achieve the best uniformity of radiation illumination. In this paper, we applied the Welder-Mead simplex-search method among various direct search method to compute the optimal ink pattern. Direct search methods are widely used to optimize the functions which are often highly nonlinear, unpredictably discontinuous, and nondifferentiable, The ink-pattern controlling the uniformity of radiation illumination is one type of these functions. In this paper, we found that simplex search methods are well suited to computing the optimal diffusive-ink pattern. In extensive numerical testing, we have found the simplex search method to be reasonably efficient and reliable at computing the optimal diffusive-ink pattern. The result also suggests that optimization can improve the functionality of simulation tools which are used to design LCD BLU.

• Journal of the Korea Safety Management & Science
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• v.13 no.1
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• pp.51-58
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• 2011

The uniformity of lighting distribution on the roadway is essential factor for drivers and pedestrians's safety during nighttime in urban streets. Also, the importance of roadside trees is one of the growing concern for better citizens' health and mitigating environmental impact on the urban street. But roadway lightings and roadside trees have different design or planting standards and they are not integrated in the systemic viewpoint for better safety of users during nighttime. The purpose of this study is to propose a simulation approach which assesses lighting quality in the view of illumination uniformity distribution of roadway lighting from design step and consider the layout of roadside trees. For improving lighting quality of roadway, simulation approach is needed for assessing the impact of diverse planting situation of trees and encouraged from beginning of design step for roadway construction.

• 한국태양에너지학회:학술대회논문집
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• 2011.04a
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• pp.282-286
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• 2011

The artificial increase in the solar intensity incident on solar cells using lenses or mirrors can allow solar cells to generate equivalent power with a lower cost. In application areas of Fresnel lenses as solar concentrators, several variations of design were devised and tested. Some PV systems still use commercially available flat Fresnel lenses as concentrators. In this study, we designed and optimized flat Fresnel lens and the 'light pipe' to develop 500X concentrated solar PV system. We performed rigorous ray tracing simulation of the flat Fresnel lens and light-pipe. The light-pipe can play imporatant roles of redistributing solar energy at the solar cell and increase the mechanical tolerance so that it can increase the lifetime of the high-concentration solar PV system and decrease the cost of manufacturing. To investigate the sensitivity of the solar power generated by the concentrated solar PV according to the performance of lens and light pipe, we performed raytracing and executed a simulation of electrical performance of the solar cell when it is exposed to the non-uniform illumination. We could conclude that we can generate 95 % or more energy compared with the energy that can be generated by perfectly uniform illumination once the total energy is given the same.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.3
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• pp.480-487
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• 2013

In this study, we researched the LED source MR16,which maintains the strong points of an ordinary MR16 while compensating for its weak points. The optical system composition of the LED MR16 includes four aspherical lens per sheet and a patterned reflector. The aspherical optical system and reflector were designed using optical software, and the performance was estimated using a lighting simulation program. Finally, a prototype was manufactured after analyzing the simulation data, and the reliability of the simulation results was estimated using a comparative analysis of the designed data and measured data.

• Journal of Microbiology and Biotechnology
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• v.13 no.5
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• pp.789-793
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• 2003

This study focused on the optimization of the illumination method for efficient use of light energies in a photobioreactor. In order to investigate the effect of radiator position, a model simulation study was carried out using Synechococcus sp. PCC 6301 and an internally radiating photobioreactor as a model system. The efficiency of light transfer in a photobioreactor was analyzed by estimating the average light intensity in a photobioreactor. The simulation result, indicate that there exists an optimal position of internal radiators, and that the optimal position varies with radiator number and cell concentration. When light radiators are placed at the optimal position, the average light intensity is about 30% higher than that obtained by placing radiators at the circumstance or center of a photobioreactor. The method presented in this work may be useful for improving light transfer efficiency in a photobioreactor.

• Journal of the Optical Society of Korea
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• v.18 no.5
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• pp.538-545
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• 2014

Microlens array (MLA) films have been used as brightness-enhancement components in many illumination systems, such as a backlight, which should meet the industrial needs of low cost and high brightness performance. A hexagonally-arranged MLA (HA-MLA) was chosen due to its high filling factor, which was a prerequisite for achieving high brightness-enhancement capability. The moir$\acute{e}$ fringes produced in a film stack composed of two HA-MLA were investigated, under four different lens configurations, by optical simulation. It was found that randomizing the lens configuration, while keeping the filling factor high, was effective way to develop high-gain MLA films for backlight applications.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.162-162
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• 2010

In this study, optical analysis for 100W LED safety street lighting was conducted. Experimental research on such single LED was the first undertaken. simulation modeling based on optical properties of single LED has compared single LED product also designed 100W simulation modeling has compared average road illuminance with Korean Industrial Standards for LED safety street lighting(KS C7658:2009). 100W safety street lighting (model: CE180-ST-OS) designed by simulation has been also compared between product and 100W simulation modeling, and error rates have showed average 5.6[%]. Designed 100W LED safety street lighting base on simulation modeling was proven by comparison experiments. Through the simulations and the corresponding analysis, it was found that the tested 100W LED safety street lamp had reasonable performance. Design method for LED safety Street lamps have been summarized, based on the optical analysis.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.765-768
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• 2008

To make 3D camera system, we check the possibility of advanced range camera module based on measuring the time delay of modulated infrared light, using a single detector chip fabricated on standard CMOS process. To depth information, electronic shutter and interlaced scanning method of 2D sensor is needed. Especially, we design "lens system, illumination unit" and review simulation result.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.579-582
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• 1999

In this paper, we propose a human face detection algorithm using adaptive skin color model and neural networks. To attain robustness in the changes of illumination and variability of human skin color, we perform a color segmentation of input image by thresholding adaptively in modified hue-saturation color space (TSV). In order to distinguish faces from other segmented objects, we calculate invariant moments for each face candidate and use the multilayer perceptron neural network of backpropagation algorithm. The simulation results show superior performance for a variety of poses and relatively complex backgrounds, when compared to other existing algorithm.

• Proceedings of the Optical Society of Korea Conference
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• 1991.06a
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• pp.29-34
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• 1991

An optoelectronic implementation of analog and non-volatile synaptic weights of neural networks is proposed by using the doping modulated amophous silicon multilayer. The persistent photoconductivity(PPC) of the multilayer induced by a short illumination is characterized in experiment and implemented to the non-volatile synaptic weights. An optoelectronic processor with the single layer perceptron algorithm is also proposed. Some learning equations of the processor and the results of simulation are presented.