• Transactions of the Korean hydrogen and new energy society
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• v.32 no.6
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• pp.551-564
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• 2021

The use of clean energy based on the hydrogen economy is increasing rapidly due to the greenhouse gas reduction policies and the increase in the need for hydrogen. Currently, South Korea government have been considering a plan to construct hydrogen refueling stations at expressway service area for the purpose of supplying hydrogen vehicles. In the case of a hydrogen refueling stations, a quantitative risk assessment (QRA) must be performed because it includs and uses a high pressurized hydrogen storage tank. In this study, QRA was conducted using societal risk and F-N curve by the consequence assessment (CA) of jet fire and explosion according to the population density, capacity of the high pressurized hydrogen storage tank and frequency assessment (FA) data to the general hydrogen refueling stations systems in expressway service area. In the cases of jet with a leak diameter of 7.16 mm, regardless of expressway service area location, the societal risk was over 1E-04 that was acceptable for as Low As reasonably practicable (ALARP) region (workforce), but unacceptable for ALARP region (public). In the cases of gas explosion, all expressway service area satisfy ALARP region. In the case of the population density is over 0.0727, QRA for constructing the hydrogen refueling stations, must be conducted.

• Journal of the Korean Institute of Gas
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• v.7 no.3 s.20
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• pp.44-50
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• 2003

The axisymmetric methane-air counterflow flame was simulated to investigate changes in the flame structure due to the fuel concentration and to evaluate the numerical method. The global strain rates $a_g=20,\;60,\;90\;s^{-1}$ and the mole fractions of methane $x_m=20,\;50,\;80\%$ in the fuel stream were taken to be numerical parameters. The axisymmetric simulation was conducted by using the Fire Dynamics Simulator (FDS) which employed a mixture fraction combustion model, and the results were compared with those of OPPDIF, which is an one-dimensional flamelet code and includes detail chemical reactions. In all the cases tested, there was good agreement in the temperature and axial velocity profiles between the axisymmetric and one-dimensional simulations. It was shown that the flame thickness and peak flame temperature increase and the flame radius decreases as the fuel concentration increases.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.10
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• pp.115-120
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• 2009

In this parer, we design the artificial intelligent direction escape light control system to improve/complete the defects of the existing fire fighting system, and sketch an optimum escape guide algorithm for its implementation. It intends to minimize human casualties and injuries by calculating/predicting moving line of the optimum emergency escape, by means of interlocking the sensor and the reception group and analyzing the data of the combustion point and the smoke movement. The optimum escape algorithm is designed by FLOYD algorithm which calculates the shortest distance. It consists of the measuring method which calculates the shortest distance by using hazardous factors for each condition in danger which is judged by the sensor installed in each area.

• Journal of Korean Society of Rural Planning
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• v.21 no.2
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• pp.163-175
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• 2015

This study aimed to analyze factors of importance and performance picked by customers of Bibijeong, a farm restaurant operated by the local community of Wanju-gun. Major points include: Recognition paths mostly were word of mouth and mass media, types of visit were in the company of friends, family members or work colleagues, and purposes of visit included consumption of meal and identifying features of the restaurant. Secondly, factor analysis showed that level of facility, atmosphere/cleanness, diversity of menu, employees, ingredients and network. The Cronbach Alpha coefficient was +0.6. Thirdly, average of importance of factors was 3.861 while average performance was 3.429. IPA analysis showed that employee(communication, customer contact) in the first quadrant proved the need for fast improvement through training. Atmosphere/cleanness (interior atmosphere, table clean, kitchen cleanliness, clean dishes, interion design) and employee(proficiency, menu recognition), foodstuff(freshness, origin, safety) in the second quadrant showed that the marketing strategy of improvement as well as maintaining current status is needed, including regular training and hygiene inspection. The third quadrant contains facilities(disability, baby, fire protection) and food menu(food packing, various menu, creative menu, menu description), network(village economic links), which showed the need for gradual improvement. The forth quadrant contains network(sights's near contains. The results so far can be summed into the statement that overcoming the basic functionality of providing meals and linking the restaurant with local attractions and local economy would be need, as well as building up the image of unique farm restaurant with local features, so that Bibijeong can serve as the centerpiece of community and foundation of exchange with other areas.

• Journal of Advanced Navigation Technology
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• v.19 no.2
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• pp.168-174
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• 2015

Wireless communication system for firefighters has an important role as the last communication method between the commander and the firefighters in disaster sites like fire. But the operation of Gyeongnam wireless communication system is installed, and maintained and controlled without criteria for the selection of a transmitting station and the analysis of propagation environment because of the lack of budget and the absence of professional personnel. To improve the performance of the radio station, this paper theoretically calculated free space loss of UHF 400 MHz band used by all firefighters in Gyeongnam and diffractions caused by single and multiple obstacles and computed the error after comparing the results of the actual measurement to those of simulation with FRAS operated by KFL. In the results, Deygout model was the most consistent with the actual measurement for 400MHz band in Kimhae site.

• Journal of Science and Technology Studies
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• v.10 no.2
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• pp.77-105
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• 2010

This essay aims to look into the possibility and limit of a technological fix with the PSD (platform screen door), which was proposed as the solution of subway risk problems. Subway risk problems may be classified into five categories-on-rail accidents, in-station accidents, platform accidents, spatial risks in underground, and risks due to a crime or terror-, and the platform accidents, which happens at the interface between the rail and the station, is the most serious and prominent. The PSD is considered as an effective technical means to prevent platform accidents. However, there remains a possibility of aggravating unexpected and invisible risks. When a fire breaks out in platforms, especially at exchange stations during the rush hour, the PSD can become a "wall of outcrying", since it may act as the "safety shutter" which killed many people in the 2003 Daegu subway disaster. This is why we need to look into the limit of a technological fix with the PSD.

• Journal of the Korean Institute of Gas
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• v.9 no.3 s.28
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• pp.1-8
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• 2005

We studied on the nondestructive evaluation of the elastic wave signals of locally wall thinned straight pipe. Wavelet transform was applied for the time-frequency analysis of waveforms obtained by fracture wave detector due to the dropping steel ball. The time-frequency analysis provides time variation of each frequency component involved in a waveform, which makes it possible to evaluate the shape of local wall thinning at each frequency. In this study, comparison by wavelet transform of the AE signals and monotonic bending tests without internal pressure are conducted on 1.91 inch diameter full-scale carbon steel pipe specimens. As the results of tests, fracture behaviors could be shown by the characteristic of mechanical strength of locally wall thinned pipes and the waveforms could be evaluated for the integrity insurance of the piping system according to the length and depth range of the deffeted shape pipes in the real field.

• Nuclear Engineering and Technology
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• v.27 no.1
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• pp.33-44
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• 1995

Public acceptance has become an important factor in nuclear power program particularly after Chernobyl accident and recent rapid democratization in Korea. Methods reflecting public opinions in order to improve public acceptance are firstly to understand what the public think about nuclear power plant and secondly to find out the public preference values for its policies. For this purpose, simplified multi-attribute utility (MAU) model was applied to analyze the public perception pattern for fire power production systems. And the conjoint analysis was applied to find out the quantitative values of public preferences for twelve policy alternatives to improve the safety and to support communities surrounding nuclear power plants in Korea. To implement these perception and preference analyses, mail survey was conducted to the Qualified sample who had the experience of visiting nuclear power plant. Diagnosis of their perception pattern for five power production systems was made by the simplified MAU model. Estimation of the quantitative preference values for potential policy alternatives was made by the conjoint measurement technique, which made it possible to forecast the effectiveness of each option. The results from the qualified sample and the methods used in this study would be helpful to set up new policy of nuclear power plant.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.2
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• pp.55-64
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• 2015

In this study, a 3-D flame cooling analysis is conducted to examine thermal safety for the flame deflector of the 75 tonf class propulsion test facility, and the safe discharge of the exhaust gas is assessed by using numerical results. The Mixture multiphase model is adopted for the simulation of heat transfer and phase exchange process between flame and cooling water, and the computational study using the single species unreacted model for the exhaust plume is carried out for the flame cooling. Numerical analysis predicts maximum temperature on the flame deflector wall for different water flow rates, and evaluates the safe minimum flow rate of water corresponding to the fire-resistant temperature for concrete.

• Journal of The Korea Institute of Healthcare Architecture
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• v.26 no.1
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• pp.73-84
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• 2020

Purpose: Though Korean healthcare services have been upgraded, infection and fire had been broken out in general hospitals. And higher concerns about quality assessment made it to clinical laboratory design guideline studies. So, this study investigates the facilities, equipment and personnel of laboratory medicine focusing on more than five hundred fifty bed hospital, and contributes to make guidelines for safety and efficiency in lab. Methods: Questionnaires to supervisor technologist and field surveys to medical laboratories in korean hospitals have been conducted for the data collection. 16 answers have been analysed statistically by MS Excel program. Results: Most of the sample tests such as hematology, clinical chemistry, immunology, transfusion, urinalysis, microbiology and molecular diagnosis are performed by more than 80% in large sized general hospital laboratory. In the test methods, automatic analyzers are used up to 80%, total laboratory automation up to 43% in clinical chemistry and immunology, and manual tests in all sorts of the test. There are placed in single lab or two and three labs above the ground, which are all in semi-open lab. There is some correlation with the number of specimens and the number of lab people depending on the number of hospital beds. Laboratory environment shows that work distance is good, but evacuation path width, visibility, separation of staff area from automatic analyzer, and equipment installations are needed to have more spaces and gears. Most of the infection controls are equipped with mechanical ventilation, air-conditioning, washbasin and wastewater separation, BSC installation and negative pressure lab room. Implications: Although the laboratory space area is calculated considering the number of hospital beds, type of tests and number of staff, hospital's expertise and the samples numbers per year should be taken into account in the planning of the hospital.