• Journal of Korean Institute of Fire Investigation
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• v.11 no.1
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• pp.41-58
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• 2008

The history of illumination has been much long since the discovery of lamplight caused huge changes in human lives. However, the swift development of the illumination actually started with the invention of a carbon filament lamp by Thomas Edison in 1878. Generally, the illumination tools plays important roles in human lives such as reduction of fatigue, improvement of safety and working efficiency, and the creation of enjoyable atmosphere. But, the illumination tools can be an origin of the fire due to carelessness and lack of management. In this study, the principle and structure of the illumination lamp were dealt with. The possibility of the fire outbreak caused by the incandescent lamp and fluorescent lamp most used in home was investigated. The examples of the fire outbreaks by the incandescent and fluorescent lamps and by the contact between the inflammable materials and the distributing wires were mentioned and demonstrated by the experimental.

• Journal of the Optical Society of Korea
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• v.17 no.5
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• pp.376-383
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• 2013

The design of the LEDs lighting in general household illumination was proposed and compared with the fluorescent lighting in this study. Using the LED as a light source would promote energy saving lighting for household illumination purposes. We used the LightTools and DIALux software to design and simulate different standards of illuminance, different correlated color temperatures and different color rendering indices for household environments. The power consumption and efficiency of traditional illuminated light sources and an LED light source with the same standard of illuminance for lighting the household environment were analyzed and compared with each other. Finally, our results show the advantages of using white-light LEDs for lighting and household illumination.

• Journal of Broadcast Engineering
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• v.24 no.1
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• pp.3-24
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• 2019

Techniques related to 360 VR service have been developed to improve the quality of the stitched image and video, where illumination compensation scheme is one of the important tools. Among the conventional illumination compensation algorithms, Gain-based compensation and Block Gain-based compensation algorithms have shown the outstanding performances in the process of making panorama picture. However, those are ineffective in the 360 VR service, because the disparity between illuminations of the multiple pictures in 360 VR is much more than that in making the panorama picture. In addition, the number of the pictures to be stitched in 360 VR system is more than that in the conventional panorama image system. Thus, we propose a preprocessing tool to enhance the illumination compensation algorithm so that the method reduces the degradation in the stitched picture of 360 VR systems. The proposed algorithm consists of 'color compensation' and 'illumination compensation'. The simulation results show that the proposed technique improve the conventional techniques without additional complexity.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.589-592
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• 2003

In the machining process of micros shape by using high-precision machining system and micro end-mill, it is important for machining characters of tools to be grasped in order to stably use tools of micro end-mill. In this study. we carried out an analytical experiment of basic machining features by using end-mill tools for the purpose of damage prevention and manufacture of high quality when the tools of micro end-mill are used. This experiment used a micro machining system with high precision and a variety of end-mill tools commercialized from tens to hundreds microns in diameter. To establish an optimal machining condition without tool damage, cutting force was analyzed according to the changes of tool diameter and cutting conditions such as cutting speed. feed rate, depth of cut. And an examination was performed for the shape and surface illumination of machining surface according to the changes of machining conditions. Based on these micro machining conditions, micro square pillar, cylinder shaft. thin wall with high aspect ratio, and micro 3-D structures such as micro gear and fan were manufactured.

• Journal of the Korea Computer Industry Society
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• v.10 no.3
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• pp.99-104
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• 2009

In this paper, fluorescent lamp on/off control and luminous intensity used an power line communication and remotely will be able to control system design. Embodied the respectively illumination equipment and tools by the network using PLC. In order to remote control and on/off of illumination equipment, luminous intensity composed a server. Will convert a previous analog system with digital system and the possibility witch will reduce an error ratio was. Consequently will be able to simplify a circuit.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.164-164
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• 2009

This paper had analyzed property of LED chip which has appropriate distribution and had designed modeling in order to experiment optical property of LED module through simulation. also throughout error value between street light and simulation data, precisive simulation could be inferred. as a consequent, transformation of optical property had henceforth verified the first value of module array.

• 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 Korean Society for Precision Engineering
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• v.30 no.2
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• pp.143-147
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• 2013

We present results of the optical design and fabrication of a light-guiding plate (LGP) for a photobioreactor by using sunlight and a linear Fresnel lens. LGP patterns were designed by optical simulations with an illumination design tool, LightTools, and fabricated by using a computerized numerical control machine. Optical characteristics of average deviation of illuminance distribution and light throughput efficiency were measured and compared with simulation results.

• Communications of Mathematical Education
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• v.33 no.4
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• pp.471-488
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• 2019

This paper aims to examine how mathematical history is used in $ textbooks according to the 2015-Revised Curriculum. We analyze the distribution and characteristics of making use of the mathematical history in the nine textbooks, using the framework suggested by Jankvist (2009) on the whys and hows of using historical tasks. First, the tasks related to mathematical history in the textbooks are mostly used as an affective tool, while few tasks are used as a cognitive tool. Second, most of the historical tasks of the type of an affective tool are introducing the anecdotes of mathematicians or in the history of mathematics, and only one case is trying to show human nature of mathematics by illuminating the difficulties mathematicians were faced with. Third, all the mathematical history tasks used as affective tools and goals are illumination materials, while only two out of the ten tasks in the category of a cognitive tool are illumination materials, yet eight others are modular ones. Considering the importance and value of using mathematical history in the math education, this paper recommends that more modular materials on mathematical history tasks in the category of cognitive tools and goals should be developed and their deployment in the textbooks or courses should be promoted. $

• Korean Journal of Optics and Photonics
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• v.19 no.4
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• pp.294-301
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• 2008

We have performed modeling and simulations of optical characteristics for a cholesteric liquid crystal (CLC) color filter. Berreman's $4{\times}4$ matrix method was used for the calculation of reflectance spectra of the CLC color filter with respect to the incident angle. The results were employed as input parameters for a user-defined coating property of an illumination design software based on the ray-tracing method, LightTools. Color shift characteristics of a planar transmission-type CLC color filter were simulated using LightTools. The results were compared with the results obtained with Berreman's $4{\times}4$ matrix method. It was found that color shift characteristics of the CLC color filter could be simulated to a reasonable accuracy when the reflectance spectra with less than 5 degrees of incremental incidence-angle were used as the input data for the user-defined coating property of LightTools. We have simulated color shift characteristics of a reflection-type CLC color filter having hemi-spherical patterns. The simulation method reported in this paper has been found to be also used for a non-planar CLC color filter structure.