• Journal of the Korea Society of Computer and Information
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• v.28 no.9
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• pp.113-120
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• 2023

The purpose of this study was conducted to provide scientific data supporting the development of health programs for enhancing adolescents' health, by understanding factors influencing their self-rated health. It conducted a composite sample χ² test of 54,848 adolescents, to understand differences in the self-rated health depending on their sociodemographic characteristics, stress and depression levels, and also implemented a logistic regression analysis, to verify the factors influencing their sense of self-rated health. As a result of the study, Male students were healthier than female students; students with greater scholarly attainments and higher economic levels were more healthier; and students who had less stress and experienced no depression showed higher sense of self-rated health. Therefore, in order to improve the self-rated health of adolescents, it is necessary to continuously manage through the establishment of a customized health promotion program.

• Journal of Industrial Convergence
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• v.21 no.6
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• pp.91-97
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• 2023

This study is a descriptive research study with secondary analysis of data from the 8th National Health and Nutrition Examination Survey. The purpose of this study was to analyze the prevalence and awareness of diabetes in 300 Korean adults aged 30 to 49 with diabetes, and to identify the factors influencing it. For data analysis, the composite sample frequency and percentage, χ²-test, and logistic regression analysis were performed using the SPSS 25.0 program. Among the diabetic patients, 171 patients (57.0%) recognized that they had diabetes, and the factors influencing cognition were gender, education level, BMI, subjective health status, cardiovascular disease, and paternal and maternal family history. Based on the results of this study, it can be used as basic data to establish policies and intervention programs that reduce the prevalence of diabetes in relatively young people aged 30 to 49 years and increase awareness among those with diabetes in Korea.

• Journal of Digital Convergence
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• v.21 no.1
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• pp.29-34
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• 2023

The purpose of this study was to find out the relationship between the frequency of consumption of sports drinks and energy drinks and aerobic physical activity in the 6-29 year old group in the National Health and Nutrition Examination Survey. The sociodemographic characteristics, aerobic physical activity, and beverage intake of the subjects were calculated using composite sample descriptive statistics, and the mean difference between groups was analyzed by cross-tabulation, χ²-test, and binary logistic regression analysis. High-intensity aerobic activity was analyzed as an increase in the intake frequency of sports drinks(ionic drinks, vitamin drinks) and energy drinks(high-caffeine drinks) (p<0.05). Compared to moderate-intensity aerobic physical activity, high-intensity aerobic physical activity was analyzed as a factor influencing the increase in beverage intake frequency. The purpose of this study was to investigate the relationship between physical activity and beverage consumption, which is a critical issue for promoting health both now and in the future, and to developed an intervention program based on the findings. Through this study, we aimed to gather basic data that can help people live healthy lives, and raise both individual and societal awareness of the importance of making better beverage choices.

• Restorative Dentistry and Endodontics
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• v.47 no.4
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• pp.36.1-36.17
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• 2022

Objectives: This study aimed to evaluate the effect of aging on the marginal quality of glass hybrid (GH) material used to elevate dentin gingival margins, and to analyze the consistency of the results obtained by 3 in vitro methods. Materials and Methods: Ten teeth received compound class II cavities with subgingival margins. The dentin gingival margins were elevated with GH, followed by resin composite. The GH/gingival dentin interfaces were examined through digital microscopy, scanning electron microscopy (SEM) using resin replicas, and according to the World Dental Federation (FDI) criteria. After initial evaluations, all teeth were subjected to 10,000 thermal cycles, followed by repeating the same marginal evaluations and energy dispersive spectroscopy (EDS) analysis for the interfacial zone of 2 specimens. Marginal quality was expressed as the percentage of continuous margin at ×200 for microscopic techniques and as the frequency of each score for FDI ranking. Data were analyzed using the paired sample t-test, Wilcoxon signed-rank test, and Pearson and Spearmen correlation coefficients. Results: None of the testing techniques proved the significance of the aging factor. Moderate and strong significant correlations were found between the testing techniques. The EDS results suggested the presence of an ion-exchange layer along the GH/gingival dentin interface of aged specimens. Conclusions: The marginal quality of the GH/dentin gingival interface defied aging by thermocycling. The replica SEM and FDI ranking results had stronger correlations with each other than either showed with the digital microscopy results.

• Journal of Industrial Convergence
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• v.21 no.11
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• pp.147-154
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• 2023

This study aimed to investigate the relationship between the general characteristics of adolescents and their mental health in relation to experiences of heavy drinking. The research utilized raw data from the 18th Youth Health Behavior Online Survey (2022), focusing on 530 participants who reported experiencing heavy drinking in the past 30 days. The study applied weighted composite sample analysis, incorporating frequency, chi-square test, and logistic regression to examine the data. According to the research findings, experiences of heavy drinking showed statistically significant differences across variables such as gender, academic achievement, economic status, sexual experience, and smoking. Additionally, among the mental health characteristics, stress perception, depression, loneliness, suicidal thoughts, suicide planning, and suicide attempts were identified as influencing factors on heavy drinking experiences. These results underscore the need for prevention programs addressing alcohol consumption habits, considering the mental and physical health of adolescents. Developing programs that take into account the relationship between mental health and drinking habits can contribute to forming healthy lifestyle habits during adolescence.

• Asia-Pacific Journal of Business
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• v.14 no.2
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• pp.51-61
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• 2023

Purpose - Since COVID-19, the government's expansion of liquidity to stimulate the economy has resulted in an increase in private debt and an increase in asset prices of such as real estate and stocks. The recent sharp rise of the US Federal fund rate and tapering by the Fed have led to a fast rise in domestic interest rates, putting a heavy burden on the Korean economy, where the level of household debt is very high. Excessive household debt might have negative effects on the economy, such as shrinking consumption, economic recession, and deepening economic inequality. Therefore, now more than ever, it is necessary to identify the causes of the increase in household debt. Design/methodology/approach - Main methodology is regression analysis. Dependent variable is household loans from depository institutions. Independent variables are consumer price index, unemployment rate, household loan interest rate, housing sales price index, and composite stock price index. The sample periods are from 2017 to May 2022, comprising 72 months of data. The comparative analysis period before and after COVID-19 is from January 2017 to December 2019 for the pre-COVID-19 period, and from Jan 2020 to December 2022 for the post-COVID-19 period. Findings - Looking at the results of the regression analysis for the entire period, it was found that increases in the consumer price index, unemployment rate, and household loan interest rates decrease household loans, while increases in the housing sales price index increase household loans. Research implications or Originality - Household loans of depository institutions are mainly made up of high-credit and high-income borrowers with good repayment ability, so the risk of the financial system is low. As household loans are closely linked to the real estate market, the risk of household loan defaults may increase if real estate prices fall sharply.

• Journal of Industrial Convergence
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• v.21 no.9
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• pp.67-75
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• 2023

The purpose of this study was to investigate difference between walking practice and happiness of one-person households according to the life cycles. This is a secondary analysis study using data from the 2021 Community Health Survey. The data were analyzed using SPSS 25 program for composite sample statistical analysis. As a result, in old age, there were many women, low education, and non-economic activities, and there were many basic living and less than 7 hours of sleep. The walking practice of one-person households was low in youth, middle age, and old age of one-person households. The level of happiness by life cycles of one-person households was 6.69 points in youth, 6.43 points in old age, and 6.19 points in middle age, and the happiness of middle age was the lowest. In youth, middle age, and old age of one-person households, there was a significant differences in happiness depending on walking practice. Therefore, social, welfare, and policy strategies should be developed to encourage walking to improve happiness of one-person households.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.588-597
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• 2016

In this study, we attempted to improve the biogas production efficiency by varying the mixing ratio of the mixed sludge of organic wastes in the improved single-phase anaerobic digestion process. The types of organic waste used in this study were raw sewage sludge, food wastewater leachate and livestock excretions. The biomethane potential was determined through the BMP test. The results showed that the biomethane potential of the livestock excretions was the highest at $1.55m^3CN4/kgVS$, and that the highest value of the composite sample, containing primary sludge, food waste leachate and livestock excretions at proportions of 50%, 30% and 20% respectively) was $0.43m^3CN4/kgVS$. On the other hand, the optimal mixture ratio of composite sludge in the demonstration plant was 68.5 (raw sludge) : 18.0 (food waste leachate) : 13.5 (livestock excretions), which was a somewhat different result from that obtained in the BMP test. This difference was attributed to the changes in the composite sludge properties and digester operating conditions, such as the retention time. The amount of biogas produced in the single-phase anaerobic digestion process was $2,514m^3/d$ with a methane content of 62.8%. Considering the value of $2,319m^3/d$ of biogas produced as its design capacity, it was considered that this process demonstrated the maximum capacity. Also, through this study, it was shown that, in the case of the anaerobic digestion process, the two-phase digestion process is better in terms of its stable tank operation and high efficiency, whereas the existing single-phase digestion process allows for the improvement of the digestion efficiency and performance.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.4
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• pp.509-518
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• 2002

The purpose of this study was to evaluate the bonding of compomer to deciduous dentin which is known to have been developed to improve the weak properties of glass ionomer cement and composite resin. 120 sound primary molars were used for the shear bond strength test and another 24 for the scanning electron microscopic evaluation. Each material was ailed into polyethylene mold attached to exposed dentinal surface($3{\times}4mm$ in diameter) of sample blocks. Shearbond strength was measured using Universal testing machine and data were analyzed statistically with Oneway-ANOVA and Scheffe test. Scanning electron microscopic observation was performed in order to evaluate the pattern of distribution and penetration of resin tags and hybrid layer. Compomer groups(II-V) showed significantly higher bond strength values than glass ionomer group(I)(p<.05). Etching-compomer groups(III, V) showed the significantly higher bond strength than non-etching compomer groups(II, IV)(p<.05), but slightly lower values than composite resin group(VI) with no statistically significant difference(p>.05). No significantly different bond strength was found between compomer groups of different bonding system(p>.05). Scanning electron micrographs showed more irregular distribution of short and thin resin tags in non-etching compomer groups(II, IV) whereas the more regular and intimate distribution of long and thick tags in etching compomer groups(III, V) and composite resin group(VI). The evaluation of hybrid layer also showed more regular formation of thicker layer in etching compomer groups(III, V). Based on the results of present study, the use of compomer as an esthetic restorative material for primary molars might be justified.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2000.04a
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• pp.9-10
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• 2000

An important business-field of world-wide steel-industry is the coating of thin metal-sheets with zinc, zinc-aluminum and aluminum based materials. These products mostly go into automotive industry. in particular for the car-body. into building and construction industry as well as household appliances. Due to mass-production, the processing is done in large continuously operating plants where the mostly cold-rolled metal-strip as the substrate is handled in coils up to 40 tons unwind before and rolled up again after passing the processing plant which includes cleaning, annealing, hot-dip galvanizing / aluminizing and chemical treatment. In the liquid Zn, Zn-AI, AI-Zn and AI-Si bathes a combined action of corrosion and wear under high temperature and high stress onto the transfer components (rolls) accounts for major economic losses. Most critical here are the bearing systems of these rolls operating in the liquid system. Rolls in liquid system can not be avoided as they are needed to transfer the steel-strip into and out of the crucible. Since several years, ceramic roller bearings are tested here [1.2], however, in particular due to uncontrollable Slag-impurities within the hot bath [3], slide bearings are still expected to be of a higher potential [4]. The today's state of the art is the application of slide bearings based on Stellite\ulcorneragainst Stellite which is in general a 50-60 wt% Co-matrix with incorporated Cr- and W-carbides and other composites. Indeed Stellite is used as the bearing-material as of it's chemical properties (does not go into solution), the physical properties in particular with poor lubricating properties are not satisfying at all. To increase the Sliding behavior in the bearing system, about 0.15-0.2 wt% of lead has been added into the hot-bath in the past. Due to environmental regulations. this had to be reduced dramatically_ This together with the heavily increasing production rates expressed by increased velocity of the substrate-steel-band up to 200 m/min and increased tractate power up to 10 tons in modern plants. leads to life times of the bearings of a few up to several days only. To improve this situation. the Mechanical Alloying (MA) TeChnique [5.6.7.8] is used to prOduce advanced Stellite-based bearing materials. A lubricating phase is introduced into Stellite-powder-material by MA, the composite-powder-particles are coated by High Energy Milling (HEM) in order to produce bearing-bushes of approximately 12 kg by Sintering, Liquid Phase Sintering (LPS) and Hot Isostatic Pressing (HIP). The chemical and physical behavior of samples as well as the bearing systems in the hot galvanizing / aluminizing plant are discussed. DependenCies like lubricant material and composite, LPS-binder and composite, particle shape and PM-route with respect to achievable density. (temperature--) shock-reSistibility and corrosive-wear behavior will be described. The materials are characterized by particle size analysis (laser diffraction), scanning electron microscopy and X-ray diffraction. corrosive-wear behavior is determined using a special cylinder-in-bush apparatus (CIBA) as well as field-test in real production condition. Part I of this work describes the initial testing phase where different sample materials are produced, characterized, consolidated and tested in the CIBA under a common AI-Zn-system. The results are discussed and the material-system for the large components to be produced for the field test in real production condition is decided. Outlook: Part II of this work will describe the field test in a hot-dip-galvanizing/aluminizing plant of the mechanically alloyed bearing bushes under aluminum-rich liquid metal. Alter testing, the bushes will be characterized and obtained results with respect to wear. expected lifetime, surface roughness and infiltration will be discussed. Part III of this project will describe a second initial testing phase where the won results of part 1+11 will be transferred to the AI-Si system. Part IV of this project will describe the field test in a hot-dip-aluminizing plant of the mechanically alloyed bearing bushes under aluminum liquid metal. After testing. the bushes will be characterized and obtained results with respect to wear. expected lifetime, surface roughness and infiltration will be discussed.