• ALGAE
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• v.17 no.2
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• pp.105-115
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• 2002

Influences of vrious environmental factors on the eutrophication of Nakdong River were analyzed statistically using water samples collected from 1 January, 1999, to 30 September, 2001 at Namji area. The relationships between the concentration of chlorophyll α (eutrophication index) and environmental factors and were analyzed to develop a statistical model which can predict the status of eutrophication. The concentation of chlorophyll α ranged from 66.2 mg · $m^{-3}$ to 70.8 mg · $m^{-3}$ during dry winter season and the average concentration during this study period was 35.5 mg · $m^{-3}$ Namji area of Nakdong River was in the hypereutrohic stage in terms of water quality. Stephanodiscus sp. and Aulacoseria granulata var. angustissima were dominant species during the witnter to spring time and summer to autumn period, respectively. Based on the correlation analysis and the analysis of variance between chlorophyll α concentration and environmental factors, significantly high positive relationships were found in the order of BOD> pH> COD > KMnO₄ consumption > DO > conductivity > alkalinity. In contrast to these factors, significantly negrative relationships were found as in the order of $PO₄^{3-}-P$ >water level>the rate of Namgang-dam discharge > NH₃-N> the rate of Andong-dam discharge> the rate of Hapchoen-dam discharge. Based on the factors analysis of environmental factors on the concentration of chlorophyll α, we obtained five factors as follows. The first factor included water level, pH, turbiditiy, conductivity, alkalinity and the rate of Namgang-dam discharge. The second factor included water temperature DO, NH₄+-N, NO₃- -N. The third factor included KMnO₄ consumption COD and BOD. The fourth factor included the rate of Andong-dam discharge, the rate of Hapcheon-dam discharge, and the rate of Imha-dam discharge. The final factor included T-N T-P and $PO₄^{3-}-P$ > concentration. We derived two statistica models that can predict the occurrence of eutrophication based on the factors by factor analysis, using regression analysis. The first model is the stepwise regression model whose independent variables are the factors produced by factor analysis : chl α (mg · $m^{-3}$ = 42.923+(18.637 factor 3) + (-17.147 factor 1) + (-12.095 factor 5) + (-4.828 factor 4). The second model is the alternative stepwise regression model whose independent variables are the sums of the standardized main component variables:chl α (mg · $m^{-3}$ = 37.295+(7.326 Zfactor 3) + (-2.704 Zfactor 1)+(-2.341 Zfactor 5).

• Journal of Environmental Health Sciences
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• v.37 no.4
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• pp.235-236
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• 2011

• Journal of Technologic Dentistry
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• v.39 no.4
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• pp.263-273
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• 2017

Purpose: This study aimed to explore the relations between class distracting factors and class satisfaction of the dental technology students and then provide a primary data to help further related studies and develop educational programs with which instructors can efficiently manage their classroom. Methods: For this study we have conducted a survey started from the beginning of May 2017 to the end of June. The subjects of the survey were Dental Technology students of D-city, K-city, W-city, selected by random sampling method. The questionnaire was self-administrated and 437 valid results were chosen for our analysis among 450 distributed questionnaires. Results: The results of the research was as follows. Firstly, The overall average point of class distracting factors was 2.5 point. The environmental factors were the highest point as 2.59 and as for the subcategories tiredness and drowsiness was the highest point as 2.76. Secondly, The overall average point of class satisfaction turned out 3,88 point and compliance with class and attitude factors gained the highest point as 4.06. Of the subcategories strict roll checking was the highest point as 4.17. Thirdly, As for class distracting factors from general characteristics a statistical significance was shown as follows; 'instructor factor'(p<.01), 'learner factor'(p<.05), 'total class distracting factor'(p<.05) in the area of gender, 'environmental factor'(p<.001), 'total class distracting factor'(p<.01), 'learner factor'(p<.05), 'instructor factor'(p<.05) in the area of gender 'learner factor'(p<.001), 'instructor factor'(p<.001), 'environmental factor'(p<.001), 'total class distracting factor'(p<.01) in the area of class grade, 'environmental factor'(p<.05) in GPA. Fourthly, A statistical significance, a negative correlation (p<.01) were shown between class distracting factors and class satisfaction. Class distracting factor that especially affects the class satisfaction was instructor factor(p<.001) and the explanatory power of the model turned out 14.7%, which was statistically meaningful (p<.001). Conclusion : Results of this study reveal that instructor factor is the key to class satisfaction of the students. So it is crucial that the instructor faithfully prepare for the class to reinforce the students' learning. Additionally further studies should be followed with more subjects and newer perspectives to develop innovative teaching methodology.

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2002.11a
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• pp.43-50
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• 2002

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.10a
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• pp.62-63
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• 2005

• Korean Journal of Occupational Health Nursing
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• v.6 no.1
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• pp.14-22
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• 1997

This study was designed to determine anxiety factors and levels of anxiety of foreign industrial workers. One hundred and seventy five workers were researched who were working in Guro Working Complex, Ansan City and Sungnam City Working Complex asking 60 questionnaires from Feb. 25, 1996 to April 12, 1996. The results were as follows ; 1. The 30.3% of foreign workers were from Nepal, 17.7% from Bangladesh, 10.9% from SriLanka, 14. 9% from Philippines, 1.1% from Ghana. 80% of foreign workers were male, 11.1% were single and most of them were in the age from 25 to 34. 37.1% of foreign workers had not lived in Korea less than 12 months, 58.8% graduated from college, 33.7% from high school, and more than half lived in a dormitory. 2. On the anxiety level related to subject workers' general characteristics, the anxiety level from Nepal recorded the highest point 2.70 statistically showing a significant difference(p=0.0003). On the physical anxiety level, the workers from Nepal recorded a significantly low point comparing with Jamaica, Burma, Vietnam and Nigeria(p=0.01). 3. Emotional anxiety level marked the highest on the workers living as a tenant comparing with the workers in dormitory. 4. On anxiety factors, the emotional anxiety recoded the highest, the social anxiety and the somatic anxiety. 5. On the relation between the anxiety factor, the somatic anxiety factor had a relation with emotional, environmental, and occupational factors and on the other relation between the anxiety factor and emotional factor had a relation with environmental, social, cultural factors. Moreover, the environmental factor had a relation with the cultural factor, social factor had a relation with the cultural factor, and cultural factor was related to the occupational factor.

• Korean Journal of Occupational Health Nursing
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• v.8 no.2
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• pp.212-220
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• 1999

This study was designed to determine anxiety factors and levels of anxiety of foreign industrial workers. One hundred and seventy five workers were researched who were working in Guro Working Complex, Ansan City and Sungnam City Working Complex asking 60 questionnaires from Feb. 25, 1996 to April 12, 1996. The results were as follows ; 1. The 30.3% of foreign workers were from Nepal. 17.7% from Bangladesh 10.9% from Srilanka, 14.9% from Philippines, 1.1% from Ghana. 80% of foreign workers were male, 77.7% were single and most of then were in the age from 25 to 34. 37.1% of foreign workers had not lived in Korea less than 12 months, 58.8% graduated from college, 33.7% from highschool, and more than half lived in a dormitory. 2. On the anxiety level related to subject workers' general characteristics, the workers level from Nepal recorded the highest point 2.70 statistically showing a significant difference(P=0.0003). On the physical anxiety level, the workers from Nepal recorded a significantly low point comparing with Jamaica, Burma, Vietnam and Nigeria(P=0.01). 3. Emotional anxiety level marked the highest on the workers living as a tenant comparing with the workers in dormitory. 4. On anxiety factors, the emotional anxiety recoded the highest, the social anxiety and the somatic anxiety. 5. On the relation between the anxiety factor, the somatic anxiety factor had a relation with emotional, environmental, and occupational factors and on the other relation between the anxiety factor and emotional factor had a relation with environmental, social, cultural factors. Moreover, the environmental factor had a relation with the cultural factor, social factor had a relation with the cultural factor, and cultural factor was related to the occupational factor.

• Journal of the Korean Institute of Landscape Architecture
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• v.32 no.1
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• pp.57-68
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• 2004

The purpose of this paper is to discover the Image and Visual Preference of the Environmental Sculpture in Urban Streetscape. For this, the analysis was preformed by the data obtained from questionnaires and from the photos of the environmental sculptures scene. The landscape image was analyzed by the factor analysis algorithm. The level of visual preference was measured by a slide simulation test, and this data was analyzed by multiple regression. The results of this study can be summarized as follows: The visual preference of the environmental sculpture has been evaluated to average 4.03 on a scale of 7 Landscape slides No. 11 and No.5 were ranked more highly for visual preference. Factors formulating the landscape image were found to be 'beauty', 'orderliness', 'emotion', and 'formation'. By using the control method for the number of factors, T.V., were obtained as 63.0%. For all experimental landscape slides, the factor of orderliness was found to be the main factor determining the visual preference. The 4 factors for visual preference were analyzed by regression as follows: Visual Preference = 3.996 + 0.341(FS1) + 0.595(FS2) + 0.222(FS3) + 0.011(FS4), R-Square = 0.520.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.2
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• pp.229-237
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• 2008

Hazardous air pollutants emitted from the oil refinery plant were surveyed from 1993 US and 2005 Korean TRI data. Toluene, xylene, methanol, MTBE and n-hexane, relatively large in amount of fugitive emission, are considered as candidates of newly designated HAPs in Korea. The sealed oil pump, one of equipments among fugitive sources in the crude oil distillation tower was examined for the estimation of amounts of annual HAPs emissions according to several calculation methods using registered emission factors. Emission rates showed to be decreased with following calculation factors; average emission factor>pegged emission factor>concentration emission factor>correlation equation. Annual emission amounts of benzene, toluene, xylene. ethyl benzene and nhexane from the distillation tower were estimated and amounts of these HAPs calculated with TVOC concentrations obtained from LDAR program and correlation equations showed only 6% of those from using concentration factors.

• Geomechanics and Engineering
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• v.29 no.5
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• pp.487-496
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• 2022

Most of the pile's vertical static load tests in construction sites are the proof load tests, which is difficult to accurately estimate the ultimate bearing capacity and analyze the reliability of piles. Therefore, a reliability analysis method based on the proof load-settlement (Q-s) data is proposed in this study. In this proposed method, a simple ultimate limit state function based on the hyperbolic model is established, where the random variables of reliability analysis include the model factor of the ultimate bearing capacity and the fitting parameters of the hyperbolic model. The model factor M = R_uR / R_uP is calculated based on the available destructive Q-s data, where the real value of the ultimate bearing capacity (R_uR) is obtained by the complete destructive Q-s data; the predicted value of the ultimate bearing capacity (R_uP) is obtained by the proof Q-s data, a part of the available destructive Q-s data, that before the predetermined load determined by the pile test report. The results demonstrate that the proposed method can easy and effectively perform the reliability analysis based on the proof Q-s data.