• Journal of the Korean Geophysical Society
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• v.4 no.4
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• pp.267-285
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• 2001

This study has tried to develop the modified DRASTIC Model by supplying the parameters,such as structural lineament density and landuse, into conventional DRASTIC medal, and to predict the potential of groundwater contamination using GIS in Whanam 2 Area, Gyeonggi Province, Korea. Since the aquifers in Korea is generally through the joints of rock-mass in hydrogeological environment, lineament denisity affects to the behavior of goundwater and contaminated plumes directly, and land-use reflect the effect of point or non-point source of contamination indirectly. For the statistical analysis, lattice layers of each parameter were generated, and then level of confidence was assessed by analyzing each correlation coefficient. Composite contamination map was achieved as a final result by comparing modified DRASTIC potential and the amount of generation load of several contaminant sources logically. The result could suggest the predictability of the area of contamination potrntial in the respects of hydrogeological aspect and water quality.

• International Journal of Highway Engineering
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• v.13 no.1
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• pp.239-249
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• 2011

The behavior of the fiber reinforced concrete (FRC) base under environmental loads was analyzed numerically as a fundamental study to develop a high structural and functional performance composite pavement system in which the base was formed using FRC and the asphalt or cement concrete surface was placed on it. A two-dimensional finite element model of the FRC base was developed and the sensitivity study was performed with the variables including slab thickness of base, thermal expansion coefficient, elastic modulus, and tensile and compressive strengths. The crack spacing and crack width were selected as representatives of the base behavior. The effects of the selected variables on the crack spacing and crack width were analyzed and the sensitive variables were determined. The results of this study could be useful to determine the optimal material properties of the FRC base for combining well with the surface materials.

• Bulletin of the Society of Naval Architects of Korea
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• v.4 no.1
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• pp.49-54
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• 1967

The authors considered the effects of trim in the small coastal passenger boat upon resistance in this paper. Any change of trim no matter how small, necessarily produces some effect upon resistance. The relations between the resistance coefficients and trim were investigated through the towing test of the Model $MCI-P_1-65$, Korean Standardized Ship, GT 70 tons passenger boat in the gravitational tank. The Lines of the Model are given in Fig. 1. Principal dimensions and other characteristics vary with the trim in general. Those values varied with the trim for $MCI-P_1-65$ are tabulated in table 1. The resistance was measured at five conditions such as even keel, 0.0273L, (original designed trim) 0.0473L, 0.0663L, 0.0873L trim by the stern, fixing the displacement corresponding to the designed load water line. Model was made of wood in length of 3.5 feet coated with varnish, and without appendages. As the artificial turbulent stimulator, the sand strip method was used. The results of model towing tests, correcting to water temperature of $70^{\circ}F$, were expanded to full scale using the Schoenherr's friction formula and surface roughness allowance coefficient of 0.0004. The authors point out, the following results. 1) Optimum trim which gives the minimum resistance exists for every speed at constant displacement and each comes to the same value. For $MCI-P_1-65$ optimum trim is 0.0673L trim by the stern(Fig.4-The cross curves of the resistancecoefficients). 2) At constant displacement, when LCB(longitudinal position of center of buoyancy) varies with the trim, there exists optimum value of LCB which gives minimum resistance for every speed and each comes to the same value. For $MCI-P_1-65$ optimum position of LCB is 8%L aft from midship section (Fig.6).

• Solar Energy
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• v.19 no.2
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• pp.1-8
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• 1999

The heat transfer characteristics of ice storage system of falling film type using sprial coil is investigated. The experimental facilities consisted of a water tank, spiral coils located above the tank, an upper water distributor, and a circulating water pump. Water is distributed uniformally over the spiral coils and it forms falling thin films. In the process of freezing, ice is formed on outside of the spiral coils through recirculation of tank water. In the process of melting, ice is melted with return water from the heat load, while the water is chilled again and drops into the tank. The results of falling film type of ice thermal storage system are as follows. The highly efficient shower flowrates for icing is near $3{\ell}/min$. Icing rates on spiral coils is rosed while brine flowrates is increased. Lower brine temperature is not only increased freezing rates but. also become higher total icing weight and overall heat transfer coefficient. Smaller shower flowrates is obtained lower water temperature on outlet for a long time. The amounts of quantity can be detected more accurately by measuring storage tank weight.

• 한국태양에너지학회:학술대회논문집
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• 2008.11a
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• pp.90-95
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• 2008

An SHGC(Solar Heat Gain Coefficient) is a determinant of total flux of solar radiation coming indoor and a critical factor in evaluating heating and cooling load. U-value represents heat loss while SHGC denominates heat gain. Recently, windows with high solar gain, mid solar gain or low solar gain are being produced with the development of Low-E coating technology. This study evaluated changes in energy consumption for heating and cooling according to changes in SHGC when using double-layered Low-E glass and triple layered Low-E glass in relation to double layered clear glass as base glass. An Office was chosen for the evaluation. For deriving optical properties of each window, WINDOW 5 by LBNL, an U.S. based company. and the results were analyzed to evaluate performance of heat and cooling energy on anannual basis using ESP-r, an energy interpretation program. Compared to the energy consumption of the double layered clear glass, the double layered Low-E glass with high solar gain consumed $69.5kWh/m^2,yr$, 9% more than the double layered clear glass in cooling energy. The one with mid solar gain consumed $63.1kWh/m^2,yr$, 1% less than the base glass while the one with low solar gain consumed $57.6kWh/m^2,yr$, 10% less than the base glass. When it comes to tripled layered glass, the ones with high solar showed 2% of increase respectively while the one with mid solar gain and low solar gain resulted 5% and 11% in decrease in energy consumption due to low acquisition of solar radiation. With respect to cooling energy. it was found that the lower the SHGC. the less energy consumption becomes.

• Tribology and Lubricants
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• v.30 no.1
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• pp.59-63
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• 2014

Laser Surface Texturing(LST) is a surface engineering process used to improve tribological characteristics of materials by creating patterned microstructures on the mechanical contact surface. In LST technology, a pulsated laser beam is used to create arranged dimples on a surface by a material ablation process, which can improve such as load capacity, wear resistances, lubrication lifetime, and reduce friction coefficients. In the present study, the effect of multi-scale LST on lubricant regime was investigated. A pulsed Nd:YAG laser was applied on the bearing steel(AISI 52100) to create arranged dimples. To optimize the surface texturing effect on friction, multi-scale texture dimples with some specific formula arrays were fabricated by combining circles, ellipses and the laser ablation process. The tribological testing of multi-scale textured surface was performed by a flat-on-flat unidirectional tribometer under lubrication and the results compared with that of the non-textured surface. Through an increase in sliding speed, the beneficial effect of multi-scale LST performance was achieved. The multi-scale textured surface had lower friction coefficient performances than the non-textured surface due to the hydrodynamic lubrication effect.

• Journal of Korean Academy of Nursing
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• v.31 no.6
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• pp.1119-1128
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• 2001

This study was designed to identify degrees of self-esteem, health status, and life satisfaction in elderly women and investigate the relationship between these factors. The results will contribute to effective nursing intervention for promoting the quality of life for elderly women. Method: The subjects of this study included 129 elderly women. The data was collected through personal interviews using questionnaires from Nov. to Dec. of 2000. The measurement tools were the self-esteem scale developed by Rosenberg and translated by Byong-Je Jong (1974), the health status scale developed by Young Ja Lee(1989), and the life satisfaction scale developed by Jin Youn(1982). The data was analyzed by the SPSS computer program, and it included descriptive statistics, x2-test, t-test and the pearson correlation coefficient. Result: The conclusions of this study are summarized as follows: 1. There was a significant difference in age (x2=12.952, p=.000), religion (x2=6.140, p=.000), spending money (x2=.7.511, p= .000), living expenses load (x2=16.189, p= .000), and the major support provider (x2=6.539, p=.000), according to general characteristics in the existence elderly women. 2. There was a significant difference in self-esteem (t=7.05, P=.000), Health status (t=-10.09, P=.000), and life satisfaction (t=6.62, P=.000) between the two groups. 3. There was a significant positive correlation between self-esteem and health status (r=.406, P=.000), self-esteem and life satisfaction (r=.524, P=.000), and health status and life satisfaction (r=.504, P= .0000) in elderly women.

• Korean Journal of Occupational Health Nursing
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• v.27 no.1
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• pp.36-47
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• 2018

Purpose: This study aimed to examine the effects of interpersonal relationship ability, job stress, and stress coping type on the turnover intention of nurses in the early stage of their careers. Methods: Data were collected from 136 early stage nurses from two general hospitals and one tertiary hospital in Chungbuk province. An early stage nurse was defined as the nurse with a work experience of 3 to 36 months. The collected data were analyzed using independent t-test, one-way ANOVA, Mann-Whitney U test, Person's correlation coefficient, and stepwise multiple regression. Results: It was seen that turnover intention had a negative correlation with interpersonal competency (r=-.20, p=.020) and a positive correlation with job stress (r=.56, p<.001). Job stress due to work over load, inadequate compensation and working environment, interpersonal relationship ability, and length of clinical career were significant factors influencing turnover intention (p<.05). These variables explained for 50.4% of the variance in turnover intention. Conclusion: It is necessary to develop an interpersonal relationship ability improvement program to decrease turnover intention among early stage nurses by helping them to successfully adapt to their job. Moreover, it is important to bring about continuous improvements in terms of provision of adequate workload and appropriate rewards, and creation of a suitable work environment to reduce the job stress of early stage nurses.

• Research in Community and Public Health Nursing
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• v.9 no.1
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• pp.30-39
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• 1998

The purpose of this study was to identify the factors influencing health promoting lifestyle of teachers and to provide the data for efficient health management of teachers. The subjects of this study were eight hundred nine teachers, who were chosen in Choong-Buk province. Survey Questionaires for data analysis were collected through visiting or mailing from September 1 to 30, 1997. The instruments used in this study were HPLP(Health Promoting Lifestyle Profile) by Walker (1987), Internal Health Locus of Control by Walston et al. (1978), Self Esteem by Rogenberg(1965), Importance of Health by Muhlenkamp (1985), Self Efficacy by Sherer & Maddux(1982), and Family Function by Olson & Schellenberg (1985). Data were analyzed by descriptive statistics, unpaired t-test, ANOVA, Pearsons correlation coefficient and stepwise multiple regression using SPSS/PC(v. 4.01) program. The results were as follows; 1. The mean of health promoting lifestyle was total 2.53 on the average, self-actualization 2.97, nutrition 2.90, interpers 52, stress management 2.33, exercise 1.91, and health responsibility 1.82 in order. The index of total health promoting lifestyle was significantly influenced by the factors including sex, age, religion, marital status, duration of work, teaching load, education level and number of family members. 2. The health promoting Lifestyle was significantly positive correlated with Self Efficacy, Family Function, Importance of Health, Internal Health Locus of Control and Self Esteem. 3. Self Efficacy was the most influential determinant predicting health promoting lifestyle of teachers. Self efficacy, Family Function, Importance of Health, Internal Health Locus of Control and Age explained 42% of the health promoting lifestyle. Based on the above findings, it is suggested to develop nursing intervention to improve Self Efficacy, Importance of Health, Family Function of teachers enhance health promoting lifestyle. Further studies are needed to confirm these findings and to determine factors which significantly influence health promoting lifestyle of teachers.

• Journal of the Korea Concrete Institute
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• v.26 no.3
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• pp.343-350
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• 2014

A probabilistic construction stage analysis using the Monte Carlo Simulation was performed to address the effects of uncertainty regarding the material properties, environmental factors, and applied forces. In the previous research, creep and shrinkage were assumed to be completely independent random variables. However, because of the common influencing factors in the material models for the creep and shrinkage estimation, strong correlation between creep and shrinkage can be presumed. In this paper, an Monte Carlo Simulation using CEB-FIB creep and shrinkage equations were performed to actually evaluate the correlation coefficient between two phenomena, and then another Monte Carlo Simulation to evaluate the statistical properties of axial strain affected by partially correlated random variables including the material properties, environmental factors, and applied forces. The results of Monte Carlo Simulation were compared with measured strains of a column on a first story in a 58-story building. Comparison indicated that the variation due to the uncertainty related with the material properties were most severe. And measured strains was within the range of mean+standard deviation.