• IEIE Transactions on Smart Processing and Computing
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• v.4 no.2
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• pp.65-70
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• 2015

In this paper, we describe the world's first real-time ray-tracing chip architecture. Ray-tracing technology generates high-quality 3D graphics images better than current rasterization technology by providing four essential light effects: shadow, reflection, refraction and transmission. The real-time ray-tracing chip named RayChip includes a real-time ray-tracing graphics processing unit and an accelerating tree-building unit. An ARM Ltd. central processing unit (CPU) and other peripherals are also included to support all processes of 3D graphics applications. Using the accelerating tree-building unit named RayTree to minimize the CPU load, the chip uses a low-end CPU and decreases both silicon area and power consumption. The evaluation results with RayChip show appropriate performance to support real-time ray tracing in high-definition (HD) resolution, while the rendered images are scaled to full HD resolution. The chip also integrates the Linux operating system and the familiar OpenGL for Embedded Systems application programming interface for easy application development.

• Korean Institute of Interior Design Journal
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• v.13 no.2
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• pp.176-183
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• 2004

This research is aimed at being a cornerstone to elicit the evaluation methodology of systematic and objective lighting design process on the basis of investigation of documentation and interviews on lighting design of architecture which is drawing more and more attention in an architectural field. In evaluating lighting design in architecture, such factors as appropriate illumination, quality of light, completion degree, reflection of use, visual amenity, understanding, amiability, artistic value, recognition, regional conditions, and extent of glare are to be more considered than anything else. In so far as general sectors of society show ever-increasing interest in lighting design, developments in both its quality and its quantity are also expected; thus, evaluation items shown in this research will be useful in appraisal of interior and exterior lighting of architecture.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1148_1149
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• 2009

반사형 전동 블라인드는 BEMS(Building Energy Management System)에 이용되는 조명 에너지 절감 장치로서, 블라인드 날개를 반사형 재질로 제작하여, 외부 채광이 블라인드 날개에 반사되어 천장에 반사되고 반사된 빛은 천장에서 확산되어 실내 깊숙이 부드럽고 균일한 조도를 공급해 준다. 이를 이용하면, 실내 거주자의 불편함 없이 실내 인공조명 사용량을 줄일 수 있다. 이를 구현하기 위해서는 태양광선의 고도의 변화에 따라 블라인드의 제어 각도를 계산하여 블라인드 제어 전동 모터를 구동해야 한다. 따라서 본 논문에서는 외부 채광을 실내 천장 면에 균일하게 반사할 수 있는 블라인드 날개의 제어 각도의 최적 조건을 제시하고, 컴퓨터 시뮬레이션을 통해 제시한 블라인드 날개 각도의 최적성을 검증하였다.

• Journal of the Korean Vacuum Society
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• v.21 no.1
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• pp.62-68
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• 2012

The conversion efficiency of solar cells depending on incident angle of light is important for building-integrated photovoltaics (BIPV) applications. The quantum efficiency is the ratio of the number of charge carriers collected by the solar cell to the number of photons of a given energy shining on the solar cell. The analysis of angle dependence of quantum efficiencies give more information upon the variation of power output of a solar cell by the incident angle of light. The variations in power output of solar cells with increasing angle of incidence is different for the type of cell structures. In this study we present the results of the quantum efficiency measurement of single-crystalline silicon solar cells and a-Si:H thin-film solar cells with the angle of incidence of light. As a result, as the angle of incidence increases in single-crystalline silicon solar cells, quantum efficiency at all wavelength (300~1,100 nm) of light were reduced. But in case of a-Si:H thin-film solar cells, quantum efficiency was increased or maintained at the angle of incidence from 0 degree to about 40 degrees and dramatically decrease at more than 40 degrees in the range of visible light. This results of quantum efficiency with increasing incident angle were caused by haze and interference effects in thin-film structure. Thus, the structural optimization considering incident angle dependence of solar cells is expected to benefit BIPV.

• Solar Energy
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• v.17 no.4
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• pp.35-43
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• 1997

An increase in the design of commercial buildings with daylighting is beginning to receive more attention, claimed by some as a second revolution in architecture. The benefits of daylighting may vary significantly because a characteristic of daylight is the way in which it varies. Indirect sunlight, however, received in the interior of a building after reflection, can serve a useful purpose as the main source of illumination. In a cloudy climate it can serve as an occasional welcome addition to the available skylight. Also, site constraints or surrounding urban context may necessitate using reflected light sources, or such sources may be an integral part of the overall design objectives and aesthetics of the proposed projects. When reflected sunlight is introduced into a space, its role in general illumination is what is of interest in this study. Results show that reflected sunlight may help the general illumination in almost same level of significance as daylight from diffuse sky. It is also summarized that the contribution of reflected sunlight to general illumination through the year round may be even and uniform regardless of the season. Consequently, introduction of reflected sunlight should be regarded as one of the successful means to enhance the visual environment in quantitative and qualitative way.

• Journal of the Korea Institute of Building Construction
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• v.18 no.3
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• pp.251-257
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• 2018

There are various quality deteriorations of concrete such as plastic, drying shrinkage due to abrupt moisture evaporation, slump loss and cold joint under hot weather condition. To protect from above deteriorations, several kinds of modified bubble sheets have been applied to secure heat insulation performance. But, there is not enough application cases of bubble sheets at job site under hot weather condition. The objective of the paper is to investigate the temperature profile and crack occurrence of the concrete covered with five different kinds of surface curing sheets, which is placed under hot weather condition. Single layer transparent bubble sheet, white colored bubble sheet, aluminum metalizing bubble sheet and PE film are adopted for surface curing sheets. Test results indicated that application of aluminum metalizing bubble sheet had most favorable effect on the reduction of on temperature rise and on the crack reduction of concrete. But due to larger reflection of light by aluminum, it brings about visual pollution to the workers. Hence, the application of white colored bubble sheet can be the most desirable alternative to protect the concrete from hot weather in the field.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.6
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• pp.241-250
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• 2019

Road signs are guide facilities for road users, and the Ministry of Land, Infrastructure and Transport has established and operated a system to enhance the convenience of managing these road signs. The role of road signs will decrease in the future autonomous driving, but they will continue to be needed. For the accurate mechanical recognition of texts on road signs, automatic road sign recognition equipment has been developed and it has applied image-based text recognition technology. Yet there are many cases of misrecognition due to irregular specifications and external environmental factors such as manual manufacturing, illumination, light reflection, and rainfall. The purpose of this study is to derive location-based destination names for finding misrecognition errors that cannot be overcome by image analysis, and to improve the automatic recognition of road signs destination names by using Levenshtein similarity verification method based on phoneme separation.

• Korean Journal of Optics and Photonics
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• v.29 no.5
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• pp.204-214
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• 2018

Since LIDAR is advantageous for accurate information acquisition and realization of a high-resolution 3D image based on characteristics that can be precisely measured, it is essential to autonomous navigation systems that require acquisition and judgment of accurate peripheral information without user intervention. Recently, as an autonomous navigation system applying LIDAR has been utilized in human living space, it is necessary to solve the eye-safety problem, and to make reliable judgment through accurate obstacle recognition in various environments. In this paper, we construct a single-shot LIDAR system (SSLs) using a 1550-nm eye-safe light source, and report the analysis method and results of LIDAR signals for various measurement environments, reflective materials, and material angles. We analyze the signals of materials with different reflectance in each measurement environment by using a 5% Al reflector and a building wall located at a distance of 25 m, under indoor, daytime, and nighttime conditions. In addition, signal analysis of the angle change of the material is carried out, considering actual obstacles at various angles. This signal analysis has the merit of possibly confirming the correlation between measurement environment, reflection conditions, and LIDAR signal, by using the SNR to determine the reliability of the received information, and the timing jitter, which is an index of the accuracy of the distance information.

• Korean Journal of Environment and Ecology
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• v.24 no.6
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• pp.751-762
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• 2010

In order to understand the influence that the plant cover condition of the high-rise building outer space causes to the temperature change, we selected 12 high-rise building constructed in Seoul City. The land cover type of the outside was classified into six type(outer road, paved surface, shrub/grassland, single-layer tree planting-site, multi-layer planting-site, and waterscape facilities) and the temperature was measured at the representative point for each type in order to analyze the land cover temperature differential for each type of the high-rise building outer space. The study area showing the temperature tendency to be similar based upon one way analysis of variance after selecting the central part of the outer road for a control and measuring a temperature in order to consider the neighboring environmental difference of the dozen building was classified into 4 groups. As to the one-way layout result of variance analysis with the land cover type of the classified group and outer space temperature, the single-layer tree planting-site, waterscape facilities, and multi-layer planting-site belonged mainly to the low temperature section. The shrub/grassland, paved surface, and outer road belonged to the high temperature region. The temperature difference between low temperature region and high temperature region is about $1.06{\sim}6.17^{\circ}C$. However, the temperature in the Outer Space of the Super-High-Rise Building was variously appeared by the influence such as the cramped of the created planting-site and waterscape facilities area, the increase of amount of solar radiation and the reduction of reflection amount of light due to building etc.. Thus, the composition all produced the area of the green quantity required for each space and water space in advance. It was determined that there were the minimum area displaying an effect and the necessity to it secures the green quantity.

• Journal of the Korean Vacuum Society
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• v.22 no.1
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• pp.13-19
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• 2013

It is expected that progress in building-integrated photovoltaic (BIPV) systems, improving the functionality and design of buildings, will be accelerated in the coming years. While the dye sensitized solar cell is considered one of the most important technologies in the BIPV field, the transparent silicon based thin film solar cell fabricated by thin film processes has drawn attention as a novel alternative. When the selective transmitting layer is applied to the solar cell, the conversion efficiency is improved due to the re-reflection of infrared light into an absorber layer with the transmission of visible light through the solar cell. In this work, we prepared Al-Ti based oxide thin films using cost-effective sputter deposition and examined their selective transmitting characteristics with various compositions. The transmittance and reflectance of the Al-Ti based oxide thin film changed with the variation of its composition, and the selective transmitting property was observed in the sample with the 25 nm-thick AlTiO layer. It is considered that the realization of transparent solar cells and the improvement of their conversion efficiency can be achieved by introducing the Al-Ti based selective transmitting layer.