• Journal of Korean Association for Spatial Structures
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• v.7 no.5
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• pp.75-82
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• 2007

The present work measured and analyzed changes in the acoustics of a sound field which has a retractable ceiling. An 1/20 scale model of an openable space was built and measurement was carried out by varying the opened area of a ceiling. The most widely used room acoustic and design parameters, RT, EDT, and D50 were investigated. The results suggest that the use of RT as an acoustic design parameter may not be proper in an openable space and further it is likely to mislead the initial acoustic design of such spaces. It is mainly due to the characteristics of RT in which non-exponential decay processes are linearly fitted. Early decay times were found to be decreased in proportion to increaing the ratio of opened area. D50, an index of speech intelligibility, was effectively shows the influence of openings on the acoustics. It is also found that EDT and D50 at the seats, not directly exposed to the opened part of a ceiling, were almost linearly decreased in proportion to the ratio of opened area, while little influence was found for the opening ratio larger than 40% at the directly exposed seats to the opened part of a ceiling.

• Korean Journal of Social Welfare
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• v.58 no.3
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• pp.371-398
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• 2006

The purpose of this study is to investigate the level of mother's caregiving satisfaction of a person with mental disorder and factors influencing to it as a positive aspect of caregiving experience. A survey conducted upon 231 mothers who live together with their adult-children with mental disorder through community mental health centers, social rehabilitation facilities and day hospitals. Collected data were analysed by t-test, Oneway-ANOVA, hierachical multiple regression analysis, and so on. The results are as follows: 1) The mean of mother's caregiving satisfaction is 3.06 in 5 point scale. Among the total items of the caregiving satisfaction scale, the means of the items 'finding strength through caregiving' and 'personal growth through caregiving' are higher than any others. 2) In the final regression model, statistically significant factors influencing to the caregiving satisfaction are 'the relationship quality between mothers and the mentally disordered', 'perceived social support from family, significant others, and friends', 'marital status of mothers', and 'family income'. Better relationship quality between mothers and the adult children with mental disorder and higher social support from family, significant others, and friends explained higher caregiving satisfaction of mothers. The level of a widow or divorced mother's caregiving satisfaction is higher than married one. The less family income affected to higher caregiving satisfaction. Variables related to mental disorder of adult-children, such as social function, years of mental disorder and frequency of hospitalization were not statistically significant influencing factors to mother's caregiving satisfaction. Through this research, the implications of social work practice were suggested in many ways.

• Korean Parent-Child Health Journal
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• v.5 no.1
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• pp.1-23
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• 2002

The purpose of this study was to find out the effect of in-service education on the nurse-newborn play interaction. The research design adopted the pre-experimental design applied only for one pretest-posttest group and Barnard's mother-infant interaction model was used as a conceptual framework. The subjects were 26 nurses who were selected from 2 nurseries in general hospital in Pusan, and 52 healthy newborns who were after 4 days from birth during data collection period at the same hospital. The data were collected from June 1st to October 5th in 2001, by video-taping for the interactive behaviors between the nurse and the newborn, played for 5 minutes in nurseries 2 weeks before and after in-service education. The in-service education consisted of the newborn's behavior responses focused on the newborn baby's states, behavior, cues and state modulation, 3 times per 1 week, 90 minutes per 1 time, lecture, demonstration and hand out project. The experimental tool used for this research was Ha Young-Soo's Korean translation of the Maternal-Infant Play Interaction Scale by Thompson, Jody Baird, Sara Gordman, Bryant(1982), some parts of which were adapted to be suitable for the purpose of this research. Mother and baby scale by Wolke & James-Roberts(1987) was also modified and used as the criterion of nurse's perception of a newborn baby. The results of this study were as follows: 1. This result supported the major hypothesis : After the intervention of in-service education, the nurse and newborn play interaction was promoted. 2. After intervention of in-service education, the nurse perception of newborn, especially the criteria of newborn's reaction was promoted., The results of this research confirm that in-service education on the newborn's behavior responses such as states, behavior, cues and state modulation is an effective way to improve the interaction between the nurse and the baby. It elevated the nurse's sensitivities to the baby's needs. Therefore, in-service education can change the conditions of current nursing practice mostly centered on physical care into a better one in which nurses consider the emotional, social, and intellectual development stages of babies. Accordingly, in-service education contributed to promoting the effective nurse-newborn play interaction so positively.

• Korean Journal of Food Science and Technology
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• v.32 no.1
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• pp.90-96
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• 2000

The optimum cooking conditions for large scale continuous gas cooker were studied with three varieties of rice. Optimum soaking time for the cooker was estimated to be 30 min at cooking temperature above $20{\circ}C$, while 60 min at cooking temperature below $10{\circ}C$. The ratio of water-to-milled rice giving the best eating quality was founded to be $1.41{\sim}1.48$, and corresponding moisture content of cooked rice ranged from 60 to 62% for different rice varieties. The optimum ratio of water to milled rice. (Chucheong) decreased from 1.50 to 1.37 with increase in the amount of milled rice from 4.0 to 6.5 kg in a cooking vessel. However, actual water uptake by rice (g water absorbed per g rice) on cooking was nearly constant value of 1.13, which means that evaporated water during cooking increases with decreasing the amount of rice in a cooking vessel.

• Journal of the Korean Geosynthetics Society
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• v.16 no.2
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• pp.139-148
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• 2017

Ground subsidence caused by damaged water pipe and sewer is recently increasing due to the aging of city and pipeline in many city. Although many recent studies have verified characteristics of ground subsidence due to wastewater pipe breakdown, research about characteristics of ground subsidence due to water pipe is insignificant. subsidence due to water pipe is insignificant. This study aims to identify the ground failure mechanism caused by water and sewer pipe breakdown. Accordingly, we conducted an indoor model experiment to verify characteristics of ground subsidence considering characteristics of ground and ground failure. The water pipe pressure and velocity head was considered to find out ground subsidence mechanism. Also comparative analysis is conducted by analyzing relative density and fine-grain content considering embedded condition of water pipe. When the relative density and seepage pressure is low, small scale ground subsidence can occur, but when the conditions are opposite, ground subsidence occur in large scale and expands to ground level over time. Furthermore, it is acknowledgeable that ground cavity that is formed after soil run off due to seepage in deep earth, maintains steady strength and stays on the ground level for long period.

• Journal of the Korean Society of Safety
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• v.20 no.4 s.72
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• pp.171-179
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• 2005

It is essential to understand the role of wall lining materials when they are exposed to a fire from an ignition source. Full-scale test methods permit an assessment of the performance of a wall lining material. Fire growth models have been developed due to the costly expense associated with full-scale testing. The models require heat flux maps from the ignition burner flame as input data. Work to date was impeded by a lack of detailed spatial characterization of the heat flux maps due to the use of limited instrumentation. To increase the power of fire modeling, accurate and detailed heat flux maps from the ignition burner are essential. High level spatial resolution for surface temperature can be provided from an infrared camera. The objective of this study was to develop a heat flux mapping procedure for a room test burner flame to a wall configuration with surface temperature information taken from an infrared camera. A prototype experiment was performed using the ISO 9705 test burner to demonstrate the developed heat flux mapping procedure. The results of the experiment allow the heat flux and spatial resolutions of the method to be determined and compared to the methods currently available.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.10
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• pp.6193-6203
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• 2014

This study was conducted to determine the quality of sleep, and its association with the sociodemographic characteristics, health-related characteristics, and job-related characteristics among male workers in small-scale manufacturing industries with fewer than 50 members. A self-administered questionnaire was distributed to 856 male workers from April $1^{st}$ to June $30^{th}$, 2011. The survey items included the variables of sociodemographic, health-related, job-related, and quality of sleep. As a result, the quality of sleep according to the PSQI of the study subjects revealed 32.0% to be good and 68.0% to be poor. The quality of sleep assessed by hierarchical multiple regression analysis was significantly lower in the married group, those with lower BMI, and those with a lower level of subjective health status, non-smoking, alcohol drinking, without regular exercise, coffee drinking, blue color, had a longer of working hours, subjective health status, had a visiting out-patient department, and had a history of hospitalization. With the above model, the job characteristics had 13.1% explanatory power. This suggests that the quality of sleep (PSQI) has more power when combined with the job characteristics.

• Journal of Korean Society of Transportation
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• v.35 no.3
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• pp.197-209
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• 2017

With the advent of age that people spend more time and money on leisure activities, there is increasing interest in professional sport games. The location of large scale sport facilities has substantial impacts on existing transportation pattern because the facility attracts and generates massive traffic volume within a short period of time. This study aims to develop a mode choice model of leisure trips of which the destinations are a sport facility. A structured SP (stated preference) survey questionnaires were developed through an experimental design, and professional sport spectators were asked to state their preference in the choice of transport mode to the sport facility. The survey results show that public transportation is preferred to passenger cars for their trip to big sports event, implying that the convenience of back home trip after the event is an important factor of their mode choice. This study is a rare research on the trip pattern to sports complex in Korea, which provides policy implications on the provision of mass transit including subway system to large scale sport complexes. And it is also expected that this study contributes to future researches on leisure trip pattern.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.10
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• pp.100-106
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• 2019

Ground and high altitude simulated combustion experiments were conducted using a liquid rocket engine with hydrogen peroxide and kerosene as the propellant. A ground and high altitude simulated combustion test facility was constructed by installing a high altitude model diffuser and TMS (Thrust Measuring System) on a vertical combustion test bench. The thrust characteristics according to altitude were investigated using the combustion test equipment. The diffuser was designed on a 1:4.8 scale to verify the characteristics of the high diffusing diffuser and starting pressure. The cold flow tests were conducted using nitrogen gas, and the performance characteristics and starting characteristics of the scale down diffuser were verified. A diffuser and TMS were installed on the vertical combustion test bench, and the thrust correction equations for the system resistance were derived. The thrust correction equations were derived from the step test and vacuum step test before the actual hot firing test. Nozzles with an operating altitude of 10km were designed. Hot firing tests were conducted to analyze the thrust characteristics according to the operating altitude changes. The actual thrust was calculated using each correction equation with the thrust value measured by the TMS.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.671-679
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• 2008

The effect of Pre-cooled Turbojet Engine installation and nozzle exhaust jet on Hypersonic Turbojet EXperimental aircraft(HYTEX aircraft) were investigated by three-dimensional numerical analyses to obtain aerodynamic characteristics of the aircraft during its in-flight condition. First, simulations of wind tunnel experiment using small scale model of the aircraft with and without the rectangular duct reproducing engine was performed at M=5.1 condition in order to validate the calculation code. Here, good agreements with experimental data were obtained regarding centerline wall pressures on the aircraft and aerodynamic coefficients of forces and moments acting on the aircraft. Next, full scale integrated analysis of the aircraft and the engine were conducted for flight Mach numbers of M=5.0, 4.0, 3.5, 3.0, and 2.0. Increasing the angle of attack $\alpha$ of the aircraft in M=5.0 flight increased the mass flow rate of the air captured at the intake due to pre-compression effect of the nose shockwave, also increasing the thrust obtained at the engine plug nozzle. Sufficient thrust for acceleration were obtained at $\alpha=3$ and 5 degrees. Increase of flight Mach number at $\alpha=0$ degrees resulted in decrease of mass flow rate captured at the engine intake, and thus decrease in thrust at the nozzle. The thrust was sufficient for acceleration at M=3.5 and lower cases. Lift force on the aircraft was increased by the integration of engine on the aircraft for all varying angles of attack or flight Mach numbers. However, the slope of lift increase when increasing flight Mach number showed decrease as flight Mach number reach to M=5.0, due to the separation shockwave at the upper surface of the aircraft. Pitch moment of the aircraft was not affected by the installation of the engines for all angles of attack at M=5.0 condition. In low Mach number cases at $\alpha=0$ degrees, installation of the engines increased the pitch moment compared to no engine configuration. Installation of the engines increased the frictional drag on the aircraft, and its percentage to the total drag ranged between 30-50% for varying angle of attack in M=5.0 flight.