• Journal of Digital Convergence
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• v.12 no.11
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• pp.427-435
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• 2014

This study was Dental health determinants of elderly people. For this purpose, a questionnaire was done for 396 elderly people of 60 or more years old who have visited Seogwipo city public health center(branch) in Jejudo from May 27th to June 5th 2013 after they heard the intention of that investigation. Result of the most answers were 'normal' for the question asking the subjective status of teeth health of whom having more than 20 natural teeth as 73.3%; the most answers of whom with less than 19 natural teeth were 'bad' as 41.4%, which showed difference(p<0.05). The factors influencing the subjective teeth health were 4.3times higher in cases of women than men. The higher educational(high school or more)had they, the more monthly average income(2 million won or more) did they have, the higher was their subjective teeth health status(p<0.01). It is more important than anything that they reserve more than 20 natural teeth until they get old to keep and improve their oral and body health. In addition to that, the oral health project or oral health program to perform country-wide programs for free, consistent and systematic oral health examination and education should be planned.

• Korean Journal of Environment and Ecology
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• v.32 no.2
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• pp.176-184
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• 2018

This study was intended to provide basic data for more ecological and systematic preservation and management planning of forest vegetations in the Baekdudaegan sector between Danmoknyeong and Guryongnyeong where biodiversity is considered to be very important. A vegetation survey using the Zurich-Montpellier (Z.-M.) method of phytosociology was carried out in a total 142 sites to examine the environmental characteristics. The survey showed the forest vegetation types of one community group, two communities, four groups, and four subgroups. Quercus mongolica and Acer pseudosieboldianum, which fall under Constancy Class V, were dominant species and deemed to be the key species of the forest ecosystem management plan for the investigated areas. Regarding species diversity, it was found that the dominant species of the VT3 type were evenly distributed in the area while the species of the VT4 type showed not only a diverse composition but also the most abundant number of species. Moreover, there were 24 of rare plants found in the Danmoknyeong-Guryongnyeong section: the critically endangered species include Dracocephalum rupestre; the endangered species include Saxifraga octopetala; the vulnerable species include Paeonia japonica, Euphorbia fauriei, Hanabusaya asiatica, and Parasenecio pseudotaimingasa; the least concern species include Aristolochia manshuriensis, Rodgersia podophylla, Salvia chanryoenica, Scopolia japonica, and Parasenecio firmus.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.21 no.6
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• pp.543-553
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• 2008

Shipbuilding is a kind of ETO(Engineering To Order) industry which designs and produces a product in accordance to various requirement of customers, rules and regulations. Recently, the number of ordered ships has been increased by up to two or three times in each domestic shipyards. Most shipyards have been adopted 3D ship CAD, ERP(Enterprise Resource Planning) and APS(Advanced Planning System) to get an efficient product development and manufacturing system. However, not only the effective operation of 3D ship CAD, ERP and APS but also the production efficiency can be achieved only if product information management which can manages the product data is implemented in an integrated environment. Present study has suggested a systematic approach to implement a PLM system to manage the product data in early design shipbuilding. Also, a prototype of PLM is implemented to manage the product data in a basic ship-design. In the prototype system, a product structure and architecture of PLM is considered.

• Korea journal of population studies
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• v.29 no.1
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• pp.57-70
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• 2006

Patterns and changes of marriage have drawn much attention as they have been pointed out a key factor of low fertility. Nonetheless, systematic studies on marriage have been quite limited. This study, using recent nationwide survey on marriage and fertility, attempts to explain whether and how intention of marriage would differ between never married men and never married women. The logit regression analysis reveals that the likelihood of planning marriage between both sexes are still different even after controlling demographic characteristics, economic status, household and family background, and attitudes toward sex and premarital cohabitation. Furthermore, important factors affecting the likelihood of planning marriage turns out to be different between men and women. For instance, men with a job is more likely than men without a job to plan marriage. However, for women, the effect of having a job is not found. Such result, with other sex differential effects of living arrangement and attitudinal variable, suggests that the mechanism through which men and women transit from singlehood to marriage would differ. More attention on gender differential should be paid in developing conceptual arguments and conducting empirical analysis regarding marriage and its related topics.

• The Journal of the Petrological Society of Korea
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• v.24 no.3
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• pp.209-231
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• 2015

In granite quarry, stones are generally quarried along easily separating planes called as 'rock cleavage'. Because orientation and characteristics of the rock cleavage are directly involved with easy quarrying, it is the most important factor on selecting a direction of digging. Using AMS (anisotropy of magnetic susceptibility), we attempt to interpret rock fabrics in Geochang Granite Stone (JS, SD, AR, GD, BW, MD quarry) and discuss about determination of rock cleavages and correlation between the rock fabrics and cleavages. Based on mean susceptibility, thermo-susceptibility curves, and hysteresis parameters, Ti-poor MD and/or PSD magnetites are the main contributor to AMS of the granite stones. The systematic magnetic foliations with sub-vertical dip angle are developed in the whole granite quarries. In most of the granite quarries, the magnetic foliations are significantly consistent with grain plane. In the BW quarry, which has higher $P_J$ values than the others, the magnetic foliations coincide exceptionally with rift plane. These results suggest that rock cleavages in granite stone are related to rock fabrics meaning shape and spatial arrangement of crystals. Magnetic fabrics analysis using AMS method, therefore, can be a quantitative and effective tool for determination of rock cleavages in granite quarry.

• Journal of dental hygiene science
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• v.16 no.5
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• pp.370-377
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• 2016

This study is conducted to provide a basis for effective management of bad breath with a poll in 155-scaling patients visiting the dental hygiene department of a university located in Gyeong-gi province after grasping the relevance among halitosis, xerostomia, and stress from them. Analysis was performed using PASW Statistics 18.0. The results of the halitosis measurements based on the general properties showed a significant difference in the hydrogen sulfide ($H_2S$) level depending on the patient's age; the highest level of 355.61 was observed in patients in their twenties followed by 227.85 in the fifties (p<0.001). The level was higher in cases with sinusitis or rhinitis (p=0.034). The $H_2S$ and $(CH_3)_2S$ levels showed are levant (r=0.492, p<0.01) correlation with the components of halitosis. Further, among other factors affecting breath odor, $(CH_3)_2S$ was shown to increase with increased stress. These results indicate that emotional factors, such as stress, should be considered when diagnosing patients with halitosis, and systematic and standardized diagnostic tools should be developed.

• Communications of Mathematical Education
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• v.34 no.3
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• pp.277-297
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• 2020

The purpose of this study was to identify and compare the mathematics educational values of pre-service and in-service elementary school teachers. For this purpose, we implemented a questionnaire investigating mathematics educational values and used principal component analysis which resulted in six components. These components were named as fun, problem-solving, representation, computation, ability, and explanation through systematic labeling processes. Both pre-service and in-service elementary school teachers considered problem-solving the most important and there was no statistical difference between the teacher groups. They also considered fun the least important and in-service elementary school teachers regarded it more important than pre-service counterparts did. All value components except explanation were regarded as important by in-service elementary school teachers, fourth-year pre-service teachers, and first-year pre-service teachers in order. The result of noticeable differences between pre-service and in-service elementary school teachers implies that actual teaching experience may affect teachers' mathematics educational values more than teacher preparation programs. Based on these findings, we need to discuss what should be regarded as important and worthwhile in teacher preparation programs to establish mathematics educational values for pre-service teachers. We also need to confirm whether the mathematics educational values by in-service elementary school teachers may be in line with what has been pursued in the national mathematics curriculum.

• Fire Science and Engineering
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• v.32 no.1
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• pp.89-98
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• 2018

Fire accidents in foreign countries, like the accident in a thermal power plant in Beijing, the accidents in domestic power plants, including Boryeong Power Plant in 2012 and Taean Power Plant in 2016, a disaster in a nuclear power plant in Fukushima in 2011 or the large-scale power failure in California in 2001 are safety accidents related to electric power, which caused losses in the people's stable lives and the countries. Electricity has an absolute impact on the people's life and the economy, so we can easily expect the serious situation affecting economic growth as well as direct damage to the protection of the people's lives and the losses of properties, if there are fire or explosion accidents or radioactive leak because of negligence in safety management, or problems because of natural disasters like an earthquake in power plants that generate electricity. In this study, it was drawn the improvement of the organizations exclusively in charge of firefighting, the operation of a program for the improvement of professional competency, the development of a customized firefighting management system for plants for systematic firefighting safety management and the improvement of the earthquake-proof correspondence system, which has recently become an issue, as measures for improvements through a survey of the actual conditions concerning the necessity of the construction of a firefighting safety management system for power plants with five power generation companies, including Korea Southern Power Co., Ltd., and the persons in charge of firefighting safety Korea Hydro & Nuclear Power Co., Ltd.

• Fire Science and Engineering
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• v.33 no.5
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• pp.94-102
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• 2019

As the importance of first responses for fire accidents has grown in the safety management of nuclear power plants, a systematic approach to measure firefighters' psychological states and competence is needed. The current study investigated the construct of the risk perception of the firefighters working near nuclear power plant sites, and then developed and validated a new scale to measure firefighters' risk perception regarding nuclear power plant accidents. The scale items were developed on the basis of literature review and interviews with the firefighters working near nuclear power plant sites. In order to validate the new scale, we recruited 180 firefighters from five fire stations in the vicinity of the nuclear power plants in Jeonnam Province, Gyeongbuk Province, and Busan. The results of exploratory factor analyses revealed that the scale consisted of five factors: "manual" reflecting a lack of response guidelines and manuals for fire incidents and radioactive material release; "fear" reflecting a fear of fire incidents in the nuclear power plants and their catastrophic consequences; "resource" reflecting a lack of protective equipment and manpower for responding to fire incidents in the nuclear power plants; "trust" reflecting trust and cooperation with the counterpart institutions for firefighting in the nuclear power plants; and "knowledge" reflecting the knowledge of radioactivity and firefighting in the nuclear power plants. Further analyses provided statistical evidence supporting for the 15-item scale's internal consistency and construct validity. Finally, We discussed the implication and limitations of the current research.

• KEPCO Journal on Electric Power and Energy
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• v.6 no.2
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• pp.173-179
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• 2020

Electric vehicles (EVs) using lithium secondary batteries (LIBs) with excellent power and long-term cycle performance are gaining interest as the successors of internal combustion engine (ICE) vehicles. However, there are few systematic researches for fast charging to satisfy customers' needs. In this study, we compare the degradation of LIB where its composition is LiNi_0.5Co_0.2Mn_0.3/Graphite with the constant current and constant power-charging method. The charging speed was set to 1C, 2C, 3C and 4C in the constant current mode and the value of constant power was calculated based on the energy at each charging speed. Therefore, by analyzing the battery degradation based on the same charging energy but different charging method; CP charging method can slow down the battery degradation at a high rate of 3C through the voltage curve, capacity retention and DC-IR. However, when the charging rate was increased by 4C or more, the deviation between the LIBs dominated the degradation than the charging method.