• Journal of dental hygiene science
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• v.16 no.3
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• pp.193-199
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• 2016

The objective of this study was to investigate the relationship between health-risk factors and oral health in Korean adolescents. This cross-sectional study was based on the 9th Korea Youth Risk Behavior Web-Based Survey (2013). The final participation rate in the survey was 96.4%. of a Total of 72,435 adolescents (age, 12~18 years) who had participated in the survey, 66,951 adolescents (33,777 boys and 33,174 girls) were selected for analysis, after excluding those with missing data. The key variables were oral health factors (one or more of the six oral symptoms), general characteristics (five factors), and health-risk factors (five factors). After adjusting for the general characteristics, frequency analysis, ${\chi}^2-test$ using PASW Statistics ver. 18.0, and logistic regression analysis were performed to understand the effects of health risk-factors on the oral symptoms experienced by the study subjects. Subjects who answered 'Yes' for alcohol consumption had a 1.33 times higher risk of experiencing oral symptoms. Further, subjects who smoked were at a 1.2 times higher risk of experiencing oral symptoms. With regard to internet use, the risk of experiencing oral symptoms was 1.25 times higher for subjects who used the internet for 7 hours or more than for those who used it for less than 1 hour. Compared to those subjects who had not experienced violence in school, the odds ratio of subjects who had experienced it 3~4 times was 1.54-fold higher. The study found that health-risk factors were associated with oral symptom experience. Therefore, programs to understand health-risk factors and interventions should be developed for Korean adolescents and provided on a regular basis along with oral health education.

• Journal of Preventive Medicine and Public Health
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• v.32 no.2
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• pp.191-199
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• 1999

Objectives: To examine the relationship between air pollution exposure and mortality in Seoul for the years of 1991-1995, Methods: Daily counts of death were analyzed by general additive Poisson model, with adjustment for effects of secular trend, seasonal factor, day of the week, heat wave, temperature, and humidity. Pollution variables were ozone, nitrogen dioxide, total suspended particles(TSP), and sulfur dioxide. Results: Daily death counts were associated with ozone(1 day before), nitrogen dioxide(1 day before), TSP(2 days before), sulfur dioxide(2 days before). The association with ozone was most statisfically significant and independent of other air pollutants. Increase of 100 ppb in ozone was associated with 0%(95% Cl= 2%-10%) increase in the daily number of death, This effect was greater in persons aged 65 and older. The relative risks of death from respiratory disease and cardiovascular disease were greater than for all-cause mortality in each pollutant. After ozone level exceeds 25 ppb, the dose-response relationship between mortality and ozone was almost linear. However, the effect of TSP, sulfur dioxide, and nitrogen dioxide on mortality might be confounded with each other. Conclusion: Daily variations in air pollution within the range currently occurring in Seoul might have an adverse effect on daily mortality.

• The Journal of Engineering Geology
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• v.30 no.3
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• pp.315-325
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• 2020

This study was performed to develop a model to predict landslides and determine the variable importance of landslides susceptibility factors based on the probabilistic prediction of landslides occurring on slopes along the road. Field survey data of 30,615 slopes from 2007 to 2020 in Korea were analyzed to develop a landslide prediction model. Of the total 131 variable factors, 17 topographic factors and 114 geological factors (including 89 bedrocks) were used to predict landslides. Automated machine learning (AutoML) was used to classify landslides and non-landslides. The verification results revealed that the best model, an extremely randomized tree (XRT) with excellent predictive performance, yielded 83.977% of prediction rates on test data. As a result of the analysis to determine the variable importance of the landslide susceptibility factors, it was composed of 10 topographic factors and 9 geological factors, which was presented as a percentage for each factor. This model was evaluated probabilistically and quantitatively for the likelihood of landslide occurrence by deriving the ranking of variable importance using only on-site survey data. It is considered that this model can provide a reliable basis for slope safety assessment through field surveys to decision-makers in the future.

• Journal of Korean Tunnelling and Underground Space Association
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• v.6 no.3
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• pp.213-225
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• 2004

The number of tunnels are in fact increasing as a part of linear improvement project of general national highway and road enlargement and pavement project. Recently, collapses of portal slope are also occurring considerably, due to local raining from severe rain storm and abnormal weather. Accordingly, it was risen a necessity to efficiently respond to tunnel portal slope damage and maintenance in Korea and oversea nations. This paper is a basic proposal to execute a survey on the current status and state of the tunnel portal slopes that were already installed and are now being operated along general national highways, and also to execute state evaluation for the purpose of managing those effectively. As a research method, domestic tunnels were analyzed in accordance with geometrical shape such as access type, portal form, and tunnel type, etc. via field survey to analyze the types of tunnel portal slopes along national highways. State evaluation classification sheet is presented to divide classes for the danger state of the surveyed portal slopes, and then the related grades are divided. It is mainly aimed at classifying the tunnel portal slope along national highways with using this state evaluation, to use it as basic data so that continuous maintenance can be executed in the future in accordance with danger classes.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.311-317
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• 2018

The purpose of this study is to identify the needs of the nursery director, teachers, parents, and the general public regarding the use of mandatory CCTV. In other words, we will examine the benefits, problems, and solutions of mandatory CCTV. The subjects of this study included families, private day care centers, private presbytery, kindergartens, teachers, parents and the general public in D metropolitan city. The research tools were modified and supplemented questionnaires appropriately for the study purpose with reference to the previous research. Collected data was analyzed by frequency and F-test using SPSS 21.0 program. The main results of this study are as follows: First, the benefits of mandatory CCTV for daycare centers is that CCTV becomes objective evidence of human rights incidents, identifies violence among children, and can take measures. In addition, mandatory CCTV can also reduce or prevent abuse. Second, major problems concerning the mandatory use of nursery school CCTV include privacy, violation of basic rights, and education. CCTV is a stressful factor that causes teachers to feel embarrassed, uncomfortable, and tense. Third, the main improvement measures for the nursery school CCTV mandate are to prevent unfair staff and complement existing guidelines for CCTV use. Based on the results of the study, we detail the benefits, problems, and solutions for the nursing home CCTV mandatory poli.

• Journal of Conservation Science
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• v.30 no.4
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• pp.335-343
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• 2014

This study classified the result of non-metallic inclusion analysis and result of microstructure investigation on the ironware excavated in the Baekje region into Han River, Geum River, and Yeongsan River to estimate the iron making temperature and study the characteristics of regional and temporal characteristics of the heat treatment technology and steel making technology. Regardless of era, bloom iron and sponge iron are judged to be the major method for making as a directreduction process in all three regions. The result of the reinterpretation of the non-metallic inclusion by the oxide ternary constitutional diagram suggest that the temperature inside of the furnace is estimated to be between $1,100{\sim}1,300^{\circ}C$ while making the steel. The magnetic iron ores are the major raw material of steel ore and irons with high $TiO_2$ are estimated to use iron sands. Ironware with $CaO/SiO_2$ rate higher than 0.4% are considered to have artificially added the flux of calcareous materials. It was found that the iron making method is the solid caburizing-steel which caburizes low-carbon steels by the CO gas and $CO_2$ gas created when heating the forging furnace with charcoal. Also, the ironware manufacturers in the Baekje during 3rd century recognized the heat treatment technology as they performed carburizing process and quenching to intentionally increase the strength of necessary parts.

• Journal of Digital Convergence
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• v.15 no.6
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• pp.513-523
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• 2017

The purpose of this study is to examine how career decision-making self-efficacy and ego-resilience of college students after military service influence college life adjustment. For this purpose, the questionnaire was administered to 234 male college students who returned to the four-year university in Jeonbuk area. The collected data were analyzed by correlation analysis and hierarchical regression using SPSS 18.0. As a result of examining the correlation between each variables, the subscale adaptation of college life adjustment and university environment adaptation showed a positive correlation with the goal selection of career decision self-efficacy and optimistic attitude of ego-resilience. Future plan of career decision-making self-efficacy, optimistic attitude of ego-resilience and personal-emotional adaptation of college life adaptation showed a positive correlation between self-evaluation of career decision self-efficacy and self-resilience confidence. As a result of hierarchical regression analysis, it was found that ego-resilience had more influence on college life adjustment than career decision self-efficacy. The limitations of this study were discussed along with the significance of this study, which was revealed through data collection only for students who came back after military service.

• Geophysics and Geophysical Exploration
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• v.21 no.1
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• pp.26-32
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• 2018

The Northeast China is an important site geologically and geophysically because of a huge volcano called Mt. Baekdu, which is one of the largest volcanoes in the world. Signs of eruption have been recently observed and people are keen to its behavior. We carried out relative travel time tomography to investigate the velocity structure between 100 ~ 600 km depth beneath Northeast China. We used teleseismic data during 2009 ~ 2011 recorded in NecessArray provided by IRIS (Incorporated Research Institute for Seismology). The relative observations were obtained by using the multi-channel cross-correlation method. Based on the tomographic results, we observed that the locations beneath which low-velocity zones are observed coincide with the locations of several volcanic regions in Northeast China. A low-velocity anomaly is revealed beneath Mt. Baekdu down to 600 km depth, which is thought to the main origin of the magma supply for Mt. Baekdu. Another low velocity anomaly is observed beneath east of the Datong volcano down to around 300 km depth, which is inferred to be related to an upwelling from deep mantle. We observed a low velocity anomaly beneath the Wudalianchi volcano down to around 200 km depth, which may imply that this volcano has been formed by an upwelling from the asthenosphere.

• Journal of Environmental Policy
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• v.12 no.3
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• pp.123-159
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• 2013

We use a multi-regional dynamic computable general equilibrium model to explain an economic effect of $CO_2$ tax on the national and regional economy of Korea. First, we compare two $CO_2$ taxes: a region-specific $CO_2$ tax and a uniform $CO_2$ tax. In the region-specific tax, the $CO_2$ tax rate in the capital area and the south-eastern region is much greater than those in other regions. GDP loss resulting from the region-specific tax is bigger than that in the uniform tax. Second, we consider three options for tax recycling: consumption tax recycling, labor-income tax recycling, and corporate-income tax recycling. The corporate-income tax recycling has the least GDP-loss effect over the three options. These results support that it is more efficient to use a uniform $CO_2$ tax rate than a region-specific $CO_2$ tax rate and that the corporate-income tax recycling is more desirable in a sense of efficiency than the consumption and labor-income tax recycling options.

• Culinary science and hospitality research
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• v.19 no.2
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• pp.149-166
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• 2013

The purpose of this study is to investigate what influence the external variables of the RFID system for eco-friendly agricultural products such as reliability, safety, effectiveness and innovation have on ease and usefulness, perceived value and behavioral intention. An empirical analysis were conducted to the general consumers over the age of 20 years who live in Seoul and Gyeonggi areas having experience of buying eco-friendly agricultural products in department stores, supermarkets and eco-friendly agricultural product specialty stores from November 10 to November 23, 2012, A total of 350 copies of questionnaire were distributed for this research and, excluding partial ones that were too concentrated on one side or found missing values, a total of 305 copies(87.1%) were used as the final statistical analysis data. The result shows that such external variables of the RFID system for eco-friendly agricultural products as liability, safety, effectiveness and innovation are useful enough as a theoretical basis for later study on RFID systems for eco-friendly agricultural products. Also, it reveals that, since all the process from production to sale of agricultural products can be seen, the products are provided safely for consumers, are objectively and rapidly investigated when problems occur, induce a positive attitude with their historical information, and are supplied through systematic management such as consumers' rights to know and choose and recall of unfit products.