• Journal of Korean Society on Water Environment
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• v.40 no.5
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• pp.229-242
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• 2024

This study investigated water quality characteristics and influencing factors of park drinking fountains having directly piped water systems by analyzing stagnation water (first draw) and water after a 10-minute flush (flushed water). First draws exhibited significant variations in residual chlorine, heavy metals, bacteria, and turbidity, which were largely influenced by usage frequency and external environmental contamination. However, water quality stabilized after flushing. A seasonal analysis indicated that the greatest difference in residual chlorine between first draws and flushed water occurred in spring, followed by that in winter when drinking fountains were discontinued, accompanied by increased zinc concentrations in stagnation water. A comparative analysis of water quality variability by faucet type revealed that push-button faucets exhibited greater variabilities in copper, zinc, and nickel levels than screw-down faucets, likely due to corrosive by-products generated from water hammer effects. Additionally, an analysis based on exterior material indicated that metal fountains experienced higher temperature increases and elevated zinc concentrations in first draws than stone fountains. Regarding installation environments, drinking fountains exposed to direct sunlight or partial shade had higher concentrations of copper, zinc, and nickel in first draws than those installed in constant shade. Overall, these findings suggest that frequent use or flushing can help maintain stable water quality with the exception of push-button faucets.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.5
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• pp.1435-1442
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• 2014

This study presented numerical simulations of smooth-bed flows in the rectangular open-channel using the source code by OpenFOAM. For the analysis of the turbulent flow, Large Eddy Simulations were carried out and the dynamic sub-grid scale model proposed by Germano et al. (1991) is used to model the residual stress term. In order to analyze the coherent structure, the uw quadrant method proposed by Lu and Willmarth (1973) is used and the contribution rate and the fraction time of the instantaneous Reynolds stress are obtained in the Reynolds stress. The results by the present study are analyzed and compared with data from previous laboratory studies and direct numerical simulations. It is found that the contribution rate of the ejection events is larger than that of sweep events over the buffer layer in the open-channel flow over the smooth bed, however, the frequency of the sweep event is higher than that of the ejection events.

• Journal of Korean Elementary Science Education
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• v.35 no.2
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• pp.150-165
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• 2016

This study aims to analyze types of science museum worksheets developed by elementary pre-service teachers and their perspectives on the requirements and necessity of science museum worksheets. As analysis subjects, this study selected 38 kinds of worksheets and reports developed by 114 elementary pre-service teachers who were in the third year of university of education. In this study, the science museum selected for elementary pre-service teachers to develop worksheets was a national science museum, composed of 'Nature and Discovery Museum', 'Science Technology and Industry Museum' and 'Children's Museum', which was located in a metropolitan city and opened in 2013. The results of this study can be summarized as follows; Firstly, as a result of analyzing the science museum worksheets developed by elementary pre-service teachers, this study found out that the experience type with hands-on and observation techniques applied was most, and as an approach method, direct manipulation, look-in observation and close observation were most. However, although these science museum worksheets were experience-oriented, many of them were survey-oriented ones that suggested too many questions through various exhibits. Secondly, as a result of analyzing requirements of science museum worksheets elementary pre-service teachers thought and described through the word tree of NVivo 10, this study extracted 10 kinds of main themes, out of which the requirement, 'A limited amount of activity should be required', showed the highest frequency. Thirdly, as a result of analyzing the necessity of science museum worksheets elementary pre-service teachers thought and described through the word tree of NVivo 10, this study extracted 9 kinds of main themes, out of which the opinion, 'It is required to help students check an exhibit which may be passed by', was most.

• Journal of the Korean Society for information Management
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• v.29 no.3
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• pp.61-77
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• 2012

This study investigated what web users share on a health website and how the demographic characteristics of users reflect health information sharing behavior. By using a content analysis method, this study analyzed 1,042 randomly chosen messages in the discussion board of a health website. The results revealed that the health website users emotionally supported other users, provided health information, and built relationships between them. Two third of the health website users shared his/her thoughts or feelings about ALS (Lou Gehrig's Disease) on the health website and one fourth of the health website users connected with others who had ALS. A half of the users actively provided information as a direct response to a question. No significant differences were discerned with regard to total posting frequency by age and gender effect. However, the male users in the 50s answered questions to others more actively and tried to manage their life better than the other age groups.

• Journal of Biomedical Engineering Research
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• v.28 no.6
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• pp.756-767
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• 2007

For the combination of phosphor screens having various thicknesses and a photodiode array manufactured by complementary metal-oxide-semiconductor (CMOS) process, we report the observation of image-quality degradation under the irradiation of 45-kVp spectrum x rays. The image quality was assessed in terms of dark pixel signal, dynamic range, modulation-transfer function (MTF), noise-power spectrum (NPS), and detective quantum efficiency (DQE). For the accumulation of the absorbed dose, the radiation-induced increase both in dark signal and noise resulted in the gradual reduction in dynamic range. While the MTF was only slightly affected by the total ionizing dose, the noise power in the case of $Min-R^{TM}$ screen, which is the thinnest one among the considered screens in this study, became larger as the total dose was increased. This is caused by incomplete correction of the dark current fixed-pattern noise. In addition, the increase tendency in NPS was independent of the spatial frequency. For the cascaded model analysis, the additional noise source is from direct absorption of x-ray photons. The change in NPS with respect to the total dose degrades the DQE. However, with carefully updated and applied correction, we can overcome the detrimental effects of increased dark current on NPS and DQE. This study gives an initial motivation that the periodic monitoring of the image-quality degradation is an important issue for the long-term and healthy use of digital x-ray imaging detectors.

• Journal of Families and Better Life
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• v.10 no.1 s.19
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• pp.75-94
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• 1992

The purpose of this study was to provide for the appropriate conflict management strategies to employed wives by investigation casual relations of conflict, resources, home management behavior and managerial satisfaction by applying a system's approach. The data were collected through the questionnaire whose respondent were 388 employed wives. The data were analyzed by various statistical methods such as Frequency, Percentage, ANOVA, F-test, T-test, Pearsons' correlation analysis, Multiple Regression analysis, Path analysys. The results of this study are as follows : 1) Input variables, throughput variables, output variables had differences significantly according to the family life cycle. The employed wives' families which are former term of the family life cycle used more appropriate conflict management strategies than latter term of FLC. That is, the employed wives' families which are former term of FLC had more abundant resources such as cohesive power of family, interaction with relatives, social support, had higher planning score, used more frequent structural management strategies. But, the managerial satisfaction had no differences. 2) For the relation of input variables and throughput variables, the more resources, the lower conflict is the higher planning, implementing score, structural management score. For the relation of throughput variables, the higher planning, implementing, structural management score is the higher managerial satisfaction score. For the relation of input variables and output variables, the more resources, the lower conflict is the higher managerial satisfaction, besides objective and material resource, subjective and psychological resource had influence. 4) among all variables affecting the managerial satisfaction, the commition of housework, cohesive power of family, wives' occupational level had indirect effect on managerial satisfaction through structural managemenet. Only the income had direct effect on managerial satisfaction.

• Fire Science and Engineering
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• v.26 no.5
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• pp.54-60
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• 2012

This study is the analysis of the actual state of hospital-based training in level 1 emergency medical technicians (EMTs) in fire station. The survey was carried out to 42 fire fighters having level 1 emergency medical technician certification from May 11 to 12 in 2012. The results showed 56.5 %, that the level 1 EMTs of roles had direct experienced. Level 1 EMTs performance frequency of clinical practice that endotracheal intubation 66.9 %, laryngeal mask airway 8.4 %, intravenous access 76.6 %, nitroglycerin sublingual 61.2 %, bronchodilator inhalation 50.0 %, fluid loading 73.8 %, ventilator apply 57.6 %, dextrose injection 57.6 %. It is necessary to investigate the continuous study on the education among the level 1 EMTs and the continuous evaluation and analysis of problems, supplemented of guidebook, practical education programs and regulation upon the operation and management of a hospital-based skill training.

• Journal of Distribution Science
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• v.17 no.11
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• pp.17-26
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• 2019

Purpose: Mobile media is gaining ground as an independent and core platform, and corporate interest and the expectations forstrategic use are rising in one-person media. Therefore, this study aims to establish interactivity, entertainment, information, professionalism, and up-to-date as the sub-factors of one-person media advertising properties, and to study the effect of one-personmedia advertising attributes on purchasing intention. Research design, data, and method: After collecting data from a total of 202 people, including 106 men and 96 women with the online survey method, frequency analysis and regression analysis were conducted using SPSS 25.0. Results: Research has shown that information, professionalism, entertainment, and up-to-date have a significant influence on purchasing intent. In addition, although information and expertise are found to have a significant influence on trust which shows a direct impact on the purchasing intention, the results of verification for the effect of purchasing intent through the medium of trust found to be significant in entertainment, information and up-to-date. Conclusions: There is a difference in Professionalism and Entertainment between men and women. This study provided the suggestions for establishing the most effective measures and marketing strategies in producing one-person media advertisements.

• Computational Structural Engineering
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• v.8 no.2
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• pp.153-161
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• 1995

The dynamic instability for snapping phenomena has been studied by many researchers. There is few paper which deal with the dynamic buckling under the load with periodic characteristics, and the behavior under periodic excitation is expected the different behavior against step excitation. In this study, the dynamic direct snapping of shallow elliptic paraboloidal shells is investigated under not only step excitation but also sinusoidal and seismic excitations, applied in the up-and-down direction. The dynamic nonlinear responses are obtained by the numerical integration of the geometrically nonlinear equations of motion, and examined by the Fourier spectral analysis in order to get the frequency-dependent characteristics of the dynamic instability for various load levels. The results show that the dynamic instability phenomenon carried out from stable to unstable region reveals considerably different mechanism depending on the characteristics of excitations.

• The Journal of Korean Academy of Prosthodontics
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• v.44 no.5
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• pp.549-560
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• 2006

Purpose : This experiment examined the effects of anodization on commercially pure titanium implant fixtures. Material & methods : The implant fixtures were anodized at three different voltage levels, producing three different levels of oxidation on the surface of the fixure. Implant were divided into four groups according to the level of oxidation. Group 1 consist of the control group of machined surface implants, Group 2 implants were treated by anodizing to 100 voltage, Group 3 implants were treated by anodizing oxidation to 200 voltage Group 4 implants were treated by anodizing oxidation to 350 voltage. Surface morphology was observed by Scanning Electron Microscope(SEM) and the surface roughness was measured using NanoScan $E-1000^{\circledR}$. Implantation of the fixtures were performed using New Zealand white rabbits. $Periotest^{\circledR}$ value(PTV) resonance frequency analysis(RFA), and removal torque were measured in 0, 2, 4, 8, 12 weeks after implantation. Results : The results of the study were as follows: 1. Values for the measured surface roughness indicate statistically significant differences in Ra, Rq, and Rt values among group 1, 2, 3, and 4 at the top portion of the thread,(p<0.05) while values at the base of the threads indicated no significant difference in these values. 2. A direct correlation between the firming voltage, and surface roughness and irregularities were observed using scanning electron microscope. 3. No statistically significant differences were found between test groups regarding $Periotest^{\circledR}$ values. 4. Analysis of the data produced by RFA, significant differences were found between group 1 and group 4 at 12 weeks after implantation.(p<0.05) Conclusions : In conclusion, no significant differences could be found among test groups up to a certain level of forming voltage threshold, beyond this firming voltage threshold, statistically significant differences occurred as the surface area of the oxide layer increased with the increase in surface porosity, resulting in enhanced bone response and osseointegration.