• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.27 no.2
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• pp.138-148
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• 2017

Objectives: Sleep quality is directly related to the health, quality of life and working capacity and is affected by age, gender, exercise, life habits. Gender dissimilarities in sleep quality are acknowledged. However, the gender difference in the quality of sleep in shift workers was not well known. Our aim was to study the less known gender differences in the quality of sleep of shift workers. Methods: 1,008 study subjects aged between 21 and 57 years among these, 637(525 male and 112 female workers) were daytime workers and 371(253 males and 118 female workers) were shift workers. Sleep quality was measured by self-report through the Pittsburg Sleep Quality Index(PSQI) and fatigue was measured by using the Chalder Fatigue Scale(CFS). All data was analyzed using SPSS version 19.0 program. The study was approved by the Institutional Review Board of the Occupational Safety and Health Research Institute. Results: Overall, sleep quality was found to be worse in shift workers than in daytime workers and in female than in male. Fatigue in shift female workers was significantly higher than in daytime female workers and shift male workers. In Spearman correlation analysis results, fatigue were significantly associated with gender, drink habit, regular exercise, working hours and sleep quality. With group male workers as the reference, the odds ratio(OR) for having a CFS was 2.115(${\beta}$ value=0.749, p<0.01), and subjective sleep quality, sleep latency, daytime dysfunction and PSQI were 1.541(${\beta}$ value=0.432, p<0.05), 2.297(${\beta}$ value=0.831, p<0.001), 1.798(${\beta}$ value=0.587, p<0.01) and 2.224(${\beta}$ value=0.799, p<0.01), respectively. Conclusions: Shift work played an important role in lowering the quality of sleep, and the effect was more pronounced in female workers than in male workers. Sleep quality was related to fatigue, especially sleep quality, sleep duration, sleep disturbances and daytime dysfunction were significantly related. Therefore, to improve fatigue and sleep quality of shift worker, it is necessary to improve healthy habits such as regular exercise, smoking cessation, and limited drinking. In particular, it is urgent to develop and implement a regular exercise program to reduce fatigue and improve the quality of sleep in workplace.

• International Commerce and Information Review
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• v.13 no.2
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• pp.3-26
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• 2011

The objective of this study is to improve export performance using e-Trade marketing systems. The use of e-Trade has been increasing but there is some controversy about the performance of e-Trade marketing for Small-to-Medium enterprises (SME). The research construct for determining the export performance is suggested and five factors are introduced in this paper such as: B2B relationship and cooperation, product complexity, online fitness, level of internationalization, and use of e-Trade marketing. Sample data were collected from the companies who are familiar with the e-Trade systems. The result shows that the use of e-Trade marketing mostly contributes to the increase of export performance. The regression and cluster analysis shows that both variables of e-Trade marketing and on-line fitness are significant to high export performance group. The implication for SMEs is that the use of e-Trade marketing methods could contribute to the increase of export performance and more analytical works need to be made for future study.

• Journal of Korean Association for Spatial Structures
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• v.6 no.1 s.19
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• pp.83-90
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• 2006

The GF(Gust Factor) method is usually used as a method to evaluate equivalent static wind loads for general structures. The GF method is performed on the assumption that the shape of the equivalent static wind load profile is typically similar to that of mean wind loads. The shape of fluctuating wind loads could be quite different with that of the mean wind loads in case of large-span structures. So, the effect of higher modes as well as first mode must be considered to evaluate the wind loads. In this study, the ACS (Advanced Conditional Sampling) method is suggested to evaluate of equivalent static wind loads after investigating about GF and LRC method. The An method ran derive effective static wind loads by combining wind pressures and inertia forces of a structure chosen at a maximum load effect. The maximum load effect is assessed with the time history analysis using pressure data measured in wind tunnel tests. Equivalent static wind loads evaluated using ACS, GF, and LRC methods are compared to verify the effectiveness of ACS method.

• Journal of the Korean Society for Library and Information Science
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• v.30 no.2
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• pp.107-125
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• 1996

The exhibit programs of library are considered an effective and imporant mechanism to satisfy the demand for information of library users and to innovate a library image. Accordingly, the purpose of this paper is to investigate their recognitions as to how librarians and library users think of the effectiveness of the exhibition programs and as to how the programs exert an influence upon libraries. For research methodology, this research is randomly questionnaired to 360 library users and 90 librarians in July 1995. The collected data is analyzed by such statistical methods as frequency, crosstabs, T test and annova. The analysis shows that there are interesting research findings as follw; 1. The exhibition programs are appeared to be effective for education of library users. 2. The programs are appeared to be effective for increased use of library materials. 3. The programs are appeared to be effective for public relations. 4. The programs are appeared to be effective for collection development. 5. They are revealed to have academic values like academic articles. In sum, among the opinions of librarians, they indicate that the programs are very important in activating the functions of library. Therefore, university libraries should lavishly support the exhibition programs with enough budget and exhibition planners to manage.

• Geophysics and Geophysical Exploration
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• v.17 no.4
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• pp.247-252
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• 2014

Gagok Mine, which is skarn deposits, includes sulfide minerals such as sphalerite, galena, chalcopyrite, and pyrrhotite. To explore these minerals, spectral induced polarization (SIP) is relatively effective compared to other geophysical exploration methods because there is a strong IP effect caused by electrode polarization. In the SIP, the chargeability related to sulfide mineral contents and the time constant related to the grain size of the minerals are obtained. For this reason, we aim to compare difference in the mineralized characteristics between two orebodies in the Gagok Mine by using the chargeability and the time constant. For this study, we sampled ores from the south of Wolgok orebody and the north of Sungok orebody. In order to recognize the mineralization characteristics, the metal content of the samples was measured by a potable XRF and the SIP data of the samples were acquired by using a laboratory SIP measurement system. As a result, the metals in the samples such as Pb, Zn, Cu, and Fe were detected by the portable XRF measurement. In particular, the Fe and Zn contents were far higher than the other metals. The Fe and the Zn were caused by the sphalerite and the pyrrhotite through microscopy. The Wolgok orebody had higher sulfide mineral contents than the Sungok orebody and the result corresponded with the chargeability result. However, we considered that the Sungok orebody had a larger sulfide mineral grain size than the Wolgok orebody because the time constant of the Sungok orebody was larger.

• Journal of Digital Convergence
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• v.18 no.10
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• pp.59-80
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• 2020

The purpose of this study is to analyze the current problems with the recovery methods and support systems for harm caused by digital sexual assault, based on cases in the U.S., U.K., and Australia. The significance of this study is the implications on problem solving related to digital sexual assault based on the legislation and systems of advanced foreign nations. The analytical method behind this study is the investigation of research literature. The reference materials are from judicial precedents, comparative analysis on media data, experts' advisory conferences, study forums, foreign theses, and documents on law and policy. As shown by the results of this study, we need to examine digital sexual exploitation and seek countermeasures from the victim's perspective after comparing foreign cases to determine the best protections and support systems. As digital sexual content can spread indefinitely, we certainly recognize the inherent difference between digital sexual crimes and offline sexual crimes. Thus, each case needs to be professionally categorized and an appropriate punishment must be suggested that satisfies the victims' needs. Ultimately, this study is meaningful for suggesting preventive measures against digital sexual crimes.

• Journal of the Korean Chemical Society
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• v.57 no.1
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• pp.138-146
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• 2013

This study examined the characteristics of the National Assessment of Educational Achievement (NAEA) in Science according to gender. It investigated gender achievement differences in the science section of the 2010 NAEA, the ratio of gender difference in achievement, the ratio of correct answers within each content domain and behavioral domain, and the items which showed high differences between males and females. The results indicate first, that, for 9th graders, females outperformed males in academic achievement in science. Second, with respect to the ratio of correct answers, males outperformed females in the advanced and below basic level groups, but females outperformed males in intermediate level groups. Third, females outperformed males in knowledge and inquiry in the behavior domains, and in chemistry and biology in the content domains. Fourth, an analysis of the items showing the largest gender gap indicated that males outperformed females in interpreting data, while females outperformed males in the items concerned with daily life and items related to the memorization of rules. This research on gender differences in science will allow teachers to complement the weaknesses of students when they study science, and support improved instructional methods in science.

• Korean Journal of Health Education and Promotion
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• v.26 no.5
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• pp.71-84
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• 2009

Objectives: This research intended to examine the relationships among social capital, socioeconomic factors, and health-related lifestyles and the effect of these factors on self-rated health in the Republic of Korea. Methods: The data of the social statistics survey that the Korea National Statistical Office conducted in 2006 were chosen and 37,928 people from them, who were 25~59 years old were sampled. This paper made path analysis to examine the relationships among social capital, socioeconomic factors, and health-related lifestyle and the influence of these factors on self-rated health. Results: In relation to the overall influences of socioeconomic factors, social capital, and health-related lifestyle on self-rated health, the following factors had a significant positive direct effect: education(0.069), subjective class(0.108), marriage(0.054), satisfaction with family relationships(0.087), reliability of institutions(0.020), citizens' participation(0.021), exercise(0.037), and refrain from smoking(0.011). However, abstinence from alcohol(-0.067) had a negative direct effect on self-rated health Conclusion: Based on the results, this paper can suggest that the plan of keeping and building up social capital should be considered in the whole aspects of the society and the project promoting drinking moderation is required to consider social culture than individuals.

• Journal of Bio-Environment Control
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• v.14 no.2
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• pp.76-82
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• 2005

Evaporative cooling pad system is one of the main cooling methods in greenhouses and its efficiency is very high. However, it has some disadvantages such as greenhouse temperature distributions are not uniform and installation cost is expensive. In this study, a CFD simulation model f3r predicting the air temperature distribution in the fan and fad cooling greenhouse was developed. The model was calibrated and validated against experimental data and a good fit was obtained. The influence of different outside wind, fan and pad height, ventilation rate, shading, and greenhouse length, were then examined. In order to reduce the internal temperature gradients, it is desired that the prevail wind direction and the fan and pad heights are considered. The simulation indicates that high ventilation rates and shading contribute to reduce the temperature gradients in the fan and pad cooling greenhouse. In order to maintain the desired greenhouse temperature, the pad-to-fan distance should be restricted according to the design climate conditions, shading and ventilation rates. The developed CFD model can be a useful tool to evaluate and design the fan and pad systems in the greenhouses with various configurations.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.2
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• pp.1375-1380
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• 2015

Nowadays, the technique to deal with the waste gas of perfluorinated compounds using plasma has been developed. As the effective decomposition techniques at many research centers and companies were investigated at home and abroad, the products have been improved with various methods. This study aims to guess the distributions of pressure and temperature through the thermal and fluid analyses inside the decomposition equipment model of waste gas. As the analysis result, the maximum pressure and the minimum pressure are 0.975Pa and -1.037Pa individually on the whole. It is shown that the pressure of air decreases gradually as the air flows from inlet to plane 1 and the pressure increases as the air flows from plane 1 to outlet. And the maximum temperature and the mimum temperature are $1718^{\circ}C$와 $26.07^{\circ}C$ individually on the whole. It is shown that the temperature of air increases gradually as the air flows from inlet to plane 4 and the temperature decreases as the air flows until outlet. It is thought that the data necessary to develop the real system can be applied by using the thermal and fluid analyses.