• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.78-81
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• 2009

A series of hydraulic tests of a fuel pump are performed using water at a room temperature. The pump is under development for 75-ton class liquid rocket engines of the open-loop gas generator type. According to the test results, the fuel pump satisfies its design requirement and its head and efficiency at the design flowrate are higher than the expected value by the computational analysis. Also, it is found that the pressure at the rear bearing outlet is higher than expected because the inlet of bypass pipe line is narrow. Furthermore, the flowrate of the secondary flow is estimated using the pressure difference of the elbow of the bypass pipe line.

• Journal of Power System Engineering
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• v.9 no.4
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• pp.137-142
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• 2005

The effects of temperature and initial crack length on impact fracture behavior of side plate material of 35 ton class FRP ship, which are composed by glass fiber and unsaturated polyester resin, were investigated. Impact fracture toughness of GF/PE composites displayed maximum value when the temperature of specimen is room temperature and $50^{\circ}C$, and with decrease in temperature of specimen, impact fracture toughness decreased. Impact fracture energy of GF/EP composites decreased with increase in initial crack length of specimen, and this value decreased rapidly when the temperature of specimen is lowest, $-25^{\circ}C$,. It is believed that sensitivity of notch on impact fracture energy were increased with decrease in temperature of specimen. As the GF/EP composites exposed in low temperature, impact fracture toughness of composites decreased gradually owing to the decrease of interface bonding strength caused by difference of thermal expansion coefficient between the glass fiber/polyester resin. Further, decrease of interface bonding strength of composites with decrease in specimen temperature was ascertained by SEM photograph of impact fracture surface.

• Journal of the Society of Naval Architects of Korea
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• v.44 no.3 s.153
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• pp.248-257
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• 2007

Turbulent flows around a sailing yacht hull were calculated using CFD technique. Grid system was generated by using Gridgen package and Fluent package was used to calculate flows around a 30ft-class yacht hull designed by MOERI. The drafts at starboard and port sides of a yacht. when the hull was heeled, were determined by adjusting the same displacement in the generated grid system. Pressure distribution on the sailing yacht hull was obtained and the changes of drag and side force by heel and leeway variation were shown. The flow calculations have been carried out both with and without free surface, and keel and rudder were included for both cases. It was found that the calculated results with free surface gives better agreement with experiments than those without free surface, although there are still a room for the improvement in correct prediction of forces.

• The International Journal of Costume Culture
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• v.12 no.1
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• pp.52-70
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• 2009

Department store has actively expanded cultural center services by providing a series of educational courses in order to increase customer visits, enhance customer satisfaction, and ultimately increase sales. In this study, cultural center members' shopping behaviors and image building of the department store were explored through focus group interviews. Results generated from a total of 7 focus group interviews with female cultural center members in their 30's through 60's are as follows. First, the consumer group who attends courses for their own purpose is 45 to 55 year-old female customers who are actively involved in consumption at the department store for their own clothing, food and restaurant. They are not often engaged in impulsive either group shopping for clothing. They are satisfied with class quality compared to low tuition whereas dissatisfied with busy schedule of a lecture room and lack of special discount benefits for members. Second, the other consumer group who attends courses for their children is consumers in their 30's. They are charged in shopping for clothing for their husbands, children, and themselves. They are suffering time poverty due to nurturing their children, therefore, they want to shop more in the department store on the day of class. However, expensive kids-care facilities are barriers to do it. Convenience, familiarity and center of culture are important images of the department store, developed through frequent visits of these customers. Eight implications for marketing strategies were generated based on study results.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.93-96
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• 2004

In the case of the front door of the apartment, which functions as an entrance, the study about noise has been less active than corridor type plane in the past, since stair room type plane was generalized. Hence, this study shows the survey about residents' thoughts of noise transmission through the front door, and after researching sound insulation of the present apartments, we figured out what the problem is. Moreover, we did an efficiency test as developing the front door, which increases sound insulation. As a result, it turned out that residents think that the noise transmission through the front door is as serious as floor impact noise, and also, the efficiency of the front door is as poor as STC 22-30. Therefore, in the developed front door, we should improve the efficiency to the level of STCSS. It will be a good way preparing for a demand of residents.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.10
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• pp.87-96
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• 2004

These days, it is essential that a business-class hotel provide customers with Internet service. So the most hotels have been installing facilities actively for Internet service. Businessmen also want to use Internet service level to their own office or home in hotel room. But now TV and VoD(partial) based-on CATV in hotel is supplied, and the additional network are installed for Internet service. The existing TV also must be replaced to HDTV within 2 or 3 years. The objective of this paper is to implement the next generation hotel multimedia service system using xDSL technology, VLAN mapping technology, and QoS technology. This system can provide each room in hotel with high-quality video service and Internet service simultaneously, and can also supply Internet access service using wireless LAN for the Places, such as lobby, conference room, and coffee shop in hotel. Therefore, this system can create the new market in hotel multimedia service field by connecting xDSL technology to VLAN mapping technology for charging and QoS technology for video stream transmission.

• Journal of the Korean housing association
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• v.21 no.1
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• pp.53-65
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• 2010

Apartment buildings represent the most typical patterns of housing in Korea. The present plans are very different from the previous ones when they appeared for the first time. Although apartment unit plans has changed drastically, they can be classified into several categories. Apartment unit plans reflects the demands of living activities and space dimensions of unit plans have the characteristics of diachronic continuity and carry the values of living culture. Thus this study aims to provide the statistical dimensional data of each room that can be actually used for the design of unit plans by sub-grouping typical unit plans. The statistical data of this study showed that apartment unit plans are shifting from 2bay/3room type to 3bay/3room type in 1990s. It is very peculiar that the typical unit plan of $60\;m^2$ area becomes to resemble that of $85\;m^2$ area. The space arrangement of typical unit plans of both $60\;m^2$ and $85\;m^2$ area is almost identical while only their space dimensions differ slightly. As the mean/mode/median values of space dimensions in a typical unit plan are converging into a range of narrow margin, space dimensions of typical unit plan are contended to be strictly regular. The statistical numeric data of various space dimensions provided in this paper can be applied practically to the design of apartment unit plans for low income class people who are disprivileged in the society.

• KIEAE Journal
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• v.17 no.3
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• pp.125-131
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• 2017

Purpose: The study is to measure concentrations of indoor air pollutants in housing and to analyze the characteristics of pollutants in housing indoor-air between summer and winter comparatively. The research result could be used as data for public health through indoor air quality management of existing housing and more as a reference for new housing. Method: It was investigated 24 middle class housings of metropolitan area in winter which have been built for the past 30 years. Concentration of HCHO, TVOC was investigated in living room at morning and night and concentration of $CO_2$ was investigated in living room and master bedroom at morning and night. SKT100-X5 was used for concentration of HCHO, TVOC and ZGm053UK for concentration of $CO_2$. The characteristics of HCHO, TVOC, $CO_2$ concentration in winter were analyzed and then the concentrations in winter were analyzed the concentrations in summer being preceding research comparatively. Result: Average concentration of TVOC in winter was 2.7 times more than that of TVOC in summer, average concentration of HCHO in winter was about 2.0 times more than that of HCHO in summer. Average concentration of $CO_2$ in the morning at living room in winter was 1.3 times more than that of $CO_2$ in summer. Average concentration of $CO_2$ in the morning at master bedroom in winter was 1.1 times more than that of $CO_2$ in summer. Average concentration of TVOC was 1.31 times more than that of HCHO and standard deviation of that was 1.73 times higher. Average concentration of $CO_2$ was almost nearly close or over to 1,000ppm being criteria of the Ministry of Environment.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.24 no.1
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• pp.100-108
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• 2021

Purpose: Percutaneous endoscopic gastrostomy (PEG) tube placements are commonly performed pediatric endoscopic procedures. Because of underlying disease, these patients are at increased risk for airway-related complications. This study compares patient characteristics and complications following initial PEG insertion with general endotracheal anesthesia (GETA) vs. anesthesia-directed deep sedation with a natural airway (ADDS). Methods: All patients 6 months to 18 years undergoing initial PEG insertion within the endoscopy suite were considered for inclusion in this retrospective cohort study. Selection of GETA vs. ADDS was made by the anesthesia attending after discussion with the gastroenterologist. Results: This study included 168 patients (GETA n=38, ADDS n=130). Cohorts had similar characteristics with respect to sex, race, and weight. Compared to ADDS, GETA patients were younger (1.5 years vs. 2.9 years, p=0.04), had higher rates of severe American Society of Anesthesiologists (ASA) disease severity scores (ASA 4-5) (21% vs. 3%, p<0.001), and higher rates of cardiac comorbidities (39.5% vs. 18.5%, p=0.02). Significant associations were not observed between GETA/ADDS status and airway support, 30-day readmission, fever, or pain medication in unadjusted or adjusted models. GETA patients had significantly increased length of stay (eβ=1.55, 95% confidence interval [CI]=1.11-2.18) after adjusting for ASA class, room time, anesthesia time, fever, and cardiac diagnosis. GETA patients also had increased room time (eβ=1.20, 95% CI=1.08-1.33) and anesthesia time (eβ=1.50, 95% CI=1.30-1.74) in adjusted models. Conclusion: Study results indicate that younger and higher risk patients are more likely to undergo GETA. Children selected for GETA experienced longer room times, anesthesia times, and hospital length of stay.

• Journal of the Korean Society of Safety
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• v.36 no.4
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• pp.71-79
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• 2021

In this study, a real-scale fuel-cell room of volume 1.36 m³ is constructed to confirm the explosion characteristics of hydrogen-air mixture gas in a hydrogen-powered house. A volume concentration of 40% is applied in the fuel-cell room as the worst-case scenario to examine the most severe accident possible, and two types of doors (made of plastic sheet and wood) are fabricated to observe their effects on the overpressure and impulse. The peak overpressure and impulse based on distance from the ignition source are experimentally observed and assessed. The maximum and minimum overpressures with a plastic-sheet door are about 20 and 6.7 kPa and those with a wooden door are about 46 and 13 kPa at distances of 1 and 5 m from the ignition source, respectively. The ranges of impulses for distances of 1-5 m from the ignition source are about 82-28 Pa·s with a plastic-sheet door and 101-28 Pa·s with a wooden door. The amount of damage to people, buildings, and property due to the peak overpressure and impulse is presented to determine the safe distance; accordingly, the safe distance to prevent harm to humans is about 5 m based on the 'injuries' class, but the structural damage was not serious.