• International Journal of Highway Engineering
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• v.17 no.5
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• pp.57-66
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• 2015

PURPOSES: Nighttime driving is very different from daytime driving because drivers must obtain nighttime sight-distances based on road lights and headlights. Unfortunately, nighttime driving conditions in Korea are far from ideal due to poor lighting and an insufficient number of road lights and inadequate operation and maintenance of delineators. This study is conducted to develop new standards for nighttime road visibility based on experiments of driver perception for nighttime visibility conditions. METHODS : In the study, perception level and satisfaction of nighttime visibility were investigated. A total of 60 drivers participated, including 34 older drivers and 31 young drivers. To evaluate driver perceptions of nighttime road visibility, fuzzy set theory was used because the conventional analysis methods for driver perception are limited in effectiveness for considering the characteristics of perception which are subjective and vague, and are generally expressed in terms of linguistic terminologies rather than numerical parameters. RESULTS : This study found that levels of nighttime visibility, as perceived by drivers, are remarkably similar to their satisfactions in different nighttime driving conditions with a log-function relationship. Older drivers evaluated unambiguously degree of nighttime visibility but evaluations by young drivers regarding it were unclear. CONCLUSIONS : A minimum value of brightness on roads was established as YUX 30, based on final analyzed results. In other words, road lights should be installed and operated to obtain more than YUX 30 brightness for the safety and comfort of nighttime driving.

• International Journal of Highway Engineering
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• v.15 no.4
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• pp.167-175
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• 2013

PURPOSES : The objective of this study is to investigate the capability of the combined model of traffic simulation, emission and air dispersion models on the impact analysis of air quality of mobile sources such as vehicles. METHODS : The improvement of the quality of life brings about the increasing interest of the public environment. Many endeavors including the travel demand management, the application of the state-of-the-art ITS technologies, the promotion of eco-friendly vehicles have been tried in transportation area to reduce the modal emissions. Especially, it is expected that the increasing number of eco-friendly vehicles in the road network would be able to reduce the pipe-tail emissions tremendously. From this perspective, we have performed a study on the impact analysis of the popularization of the eco-friendly vehicle in the place of the fossil fuel energy powered vehicles on the surrounding air quality using the combined framework of microscopic traffic simulation, emission and air dispersion model. RESULTS : The combined model successfully captured the effect of moving to the eco-friendly vehicles on the air quality, and the results showed that the increasing usage of eco-friendly vehicles can improve the surrounding air quality tremendously and that the air dispersion model plays a crucial role in the investigation of the air quality change around the main corridor. CONCLUSIONS : This study demonstrated the capability of the combined model showing the spatio-tempral change of emission concentration.

• Conservation Science in Museum
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• v.23
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• pp.17-30
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• 2020

This study presents the results of conservation treatment and research on a folding screen with embroidered classical Chinese characters "壽" (su) for longevity and "福" (bok) for good fortune in various scripts. The project was conducted as part of the program for supporting overseas Korean galleries in 2016. The present mounting of this ten-panel folding screen was difficult to identify as it had previously been remounted in a modern style. However, clues to the original mounting were discovered during the conservation process. It was revealed that the folding screen was decorated with colors frequently used in Joseon-period, such as teal silk at the top and bottom of each panel and a violet frame. These features provided clues to the original mounting of the folding screen, of which only a few elements have survived. Since this study analyzes only case of one folding screen, further research is required to reveal the method of mounting folding screens applied during this same period.

• Journal of the Korean Society for Heat Treatment
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• v.25 no.3
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• pp.134-137
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• 2012

We have considered the effect of electron irradiation energy of 300, 600 and 900 eV on structural, electrical and optical properties of $In_2O_3$ films prepared with RF magnetron sputtering. In this study, the thin film crystallization, optical transmittance and sheet resistance are dependent on the electron's irradiation energy. The electron irradiated $In_2O_3$ films at 900 eV are grown as a hexagonal wurtzite phase. The sheet resistance decreases with a increase in electron irradiation energy and $In_2O_3$ film irradiated at 900 eV shows the lowest sheet resistance of $110{\Omega}/{\Box}$. The optical transmittance of $In_2O_3$ films in a visible wave length region also depends on the electron irradiation energy. The film that at 900 eV shows the higher figure of merit than another films prepared in this study.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.2
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• pp.116-124
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• 2011

To purpose of this study is to develop the new type of precast concrete baseplate which is only for bimodal tram. The experiments with real size specimens, which are hollowed precast baseplate, prove the efficacy of new designed baseplate by comparing with the result of RCAHEST. Through tests progressed according to different loading locations, the specimens show the stability by the safety factor of 8~9. Also the results of RCAHEST that is the nonlinear finite element method program, appropriately estimate the occuring crack on concrete, yielding reinforcement and ultimate behavior at failure.

• Korean Journal of Optics and Photonics
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• v.22 no.5
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• pp.223-229
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• 2011

We present a low jitter frequency up-conversion detector based on quasi-phase matched sum frequency generation in a periodically poled $LiNbO_3$ waveguide for efficient single-photon detection at 1.5 ${\mu}m$ telecommunication wavelengths. The maximum detection efficiency and the noise count rate using the pump power of 300 mW and the pump wavelength of 974 nm are about 7% and 480 kHz, respectively. We also characterize the timing jitter of the frequency up-conversion detector by analyzing the time distribution of the detection outputs for photons generated through a picosecond pump pulsed spontaneous parametric downconversion. The minimum timing jitter was measured to be about 39.1 ps. Coincidence measurement with a narrow time window for pulsed up-conversion photons can eliminate the unwanted noise counts and maximize signal to noise ratio.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.133-136
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• 2008

Moment redistribution problem that reflects plasticity concept is foundation of limit state design and it has been interested to design engineers and researchers for a long time, because it enables the reasonable estimation of strength of structures through amount of reinforcement control about negative moment in support. Many researchers find that moment redistribution closely related to ductility of degree of structure and there are a lot of difficulties in achieving the reliable experimental results because of a lot of restriction of experiment. So, studies are achieved for indirect estimate methods about ductility ability of structures. Each design standards limits that the degree of redistribution of bending moment is based on the measurement of ductility of structure, and it shows conservative results. In this study, with these results, present the basic data for reasonable strength estimation methods and allowed moment redistribution of reinforced concrete continuous beams.

• Journal of the Earthquake Engineering Society of Korea
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• v.15 no.2
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• pp.35-42
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• 2011

The seismic design of solid reinforced concrete bridge columns has been committed to, based on accumulated research and design specifications. The rational confinement model and seismic performance evaluation, however, are insufficient because of the lack of domestic and foreign design specifications about the experimental and analytical difficulties in the case of circular hollow reinforced concrete columns. In this paper, the seismic behavior of circular hollow reinforced concrete columns and its dependence on design variables are understood and explained. These research results can be used to derive the rational and economical design specifications for circular hollow sectional columns based on the result from the nonlinear analysis program, named RCAHEST (Reinforced Concrete Analysis in Higher Evaluation System Technology).

• Korean Journal of Crystallography
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• v.9 no.1
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• pp.64-70
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• 1998

Porous body was prepared from coal fly ash 70 wt%0clay 30 wt% slip using DCC(Direct Coagulated Casting) method. Effect of the specific gravity of the slip on the pore size and distribution of the sintered body was examined by the SEM observation of microstructure and mercury porosimetry measurement of the pore size distribution. Average pore size of the porous sintered body was about 2.5μm for all slips with specific gravity of 1.55, 1.60 and 1.65g/cm3, respectively. Sintered body prepared from the slip of specific gravity of 1.60g/cm3 have the narrowest pore size distribution. slip of specific gravity of 1.55g/cm3 shows broader pore size distribution due to slow gellation process. Slip of specific gravity of 1.65g/cm3 required large amount of deflocculant and showed large variation of the viscosity with addition of coagulant which resulted in very unstable slip properties.

• Journal of Applied Reliability
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• v.12 no.1
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• pp.13-24
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• 2012

This paper applied the Blue Print and FMEA (Failure Mode and Effect Analysis) to education service in order to raise the education service satisfaction. First, the Blue Print is deployed to come up with strategies to overcome the fail possibility point and waiting point. Next, in order to analyze the fail factors and alternative strategies, the Blue Print of education service is applied to FMEA. The results are as follows; first, the ommission from information document by web-mail or e-mail, Second, thing that selected in spite of company uneducated, thing that omitted despite the company is target, and the unsatisfaction of attendee about training contents. Third, the delay of counsel at the telephone reply, erroneous list of course name and attendee at HRD (Human Resource Development), omission of check whether attends or not. Except for unsatisfaction of attendee, all appears at the process that service delivered. And the unsatisfaction of attendee is about education contents. Both is the factor which have influence on the education service quality. The strategies to remove the failure mode are training and manual development on service and work, a thorough management and check of information system like as ERP (Enterprise Resoure Planning), HRD, education institution list DB (Data Base), on-line application system, a development of education program to offer best education that reflect the user needs and continuously changing environment.