• Restorative Dentistry and Endodontics
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• v.30 no.6
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• pp.450-460
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• 2005

The aim of this study was to evaluate the effect of cavity shape, bond quality of bonding agent and volume of resin composite on shrinkage stress developed at the cavity floor. This was done by measuring the shear bond strength with respect to iris materials (cavity shape , adhesive-coated dentin as a high C-factor and Teflon-coated metal as a low C-factor), bonding agents (bond quality: $Scotchbond^{TM}$ Multi-purpose and Xeno III) and iris hole diameters (volume; 1mm or 3mm in $diameter{\times}1.5mm$ in thickness). Ninety-six molars were randomly divided into 8 groups ($2{\times}2{\times}2$ experimental setup). In order to simulate a Class I cavity, shear bond strength was measured on the flat occlusal dentin surface with irises. The iris hole was filled with Z250 restorative resin composite in a bulk-filling manner. The data was analyzed using three-way ANOVA and the Tukey test. Fracture mode analysis was also done When the cavity had high C-factor, good bond quality and large volume, the bond strength decreased significantly The volume of resin composite restricted within the well-bonded cavity walls is also be suggested to be included in the concept of C-factor, as well as the cavity shape and bond quality. Since the bond quality and volume can exaggerate the effect of cavity shape on the shrinkage stress developed at the resin-dentin bond, resin composites must be filled in a method, which minimizes the volume that can increase the C-factor.

• Journal of Nutrition and Health
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• v.51 no.1
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• pp.87-102
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• 2018

Purpose: The purpose of this study was to develop a valid instrument for measuring the dietary quality and behaviors of Korean elderly. Methods: The development of the Nutrition Quotient for Elderly (NQ-E) was conducted in three steps: item generation, item reduction, and validation. The 41 items of the NQ-E checklist were derived from a systematic literature review, expert in-depth interviews, statistical analyses of the fifth Korean National Health and Nutrition Examination Survey data, and national nutrition policies and recommendations. Pearson's correlation was used to determine the level of agreement between the questionnaires and nutrient intake level, and 24 items were selected for a nationwide survey. A total of 1,000 nationwide elderly subjects completed the checklist questionnaire. The construct validity of the NQ-E was assessed using confirmatory factor analysis, LISREL. Results: The nineteen checklist items were used as final items for NQ-E. Checklist items were composed of four-factors: food behavior (6 items), balance (4 items), diversity (6 items), and moderation (3 items). The standardized path coefficients were used as the weights of the items. The NQ-E and four-factor scores were calculated according to the obtained weights of the questionnaire items. Conclusion: NQ-E would be a useful tool for assessing the food behavior and dietary quality of the elderly.

• Journal of Korea Port Economic Association
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• v.25 no.3
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• pp.139-164
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• 2009

The purpose of this paper is to investigate the value chain efficiency of Korean port investment by using the newly developed multi-year and multi-stage value chain efficiency model of DEA(Data Envelopment Analysis). Inputs[port investment amount, cargo handling capacity, and berthing capacity], and outputs[cargo handling amount, number of ship calls, revenue, and score of customer service satisfaction] are used during 14 years(1994-2007) for 20 Korean seaports by using two kinds of DEA models. Empirical main results are as follows: First, Model 1 shows that the ranking order of multi-stage value chain efficiency is Stage 2, Stage 3-1, Stage 1, and Stage 3-2. And according to the value chain average efficiency scores, ranking order is stages 2, 1, 3-1, and 3-2. In Model 2, 3(Incheon, Mogpo, and Jeju) out of 9 ports show the ranking order of Stages 2, 3-2, 3-1, and 1. And value chain average efficiency scores rank in order of Stages 2, 3-2, 3-1, and 1. Second, the difference among the value chain efficiency scores of each stage comes from the efficiency deterioration of all ports except Stages 2 and 1 in Model 1. In Model 2, value chain efficiency scores among the Stages 3-1, 3-2 compared to Stage 1 were deteriorated. The main policy implication based on the findings of this study is that the manager of port investment and management of Ministry of Land, Transport and Maritime Affairs in Korea should introduce the multi-year, multi-stage value chain efficiency method for deciding the port investment amount and evaluating the effect of port investment after considering the empirical results of this paper carefully.

• Journal of Ginseng Research
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• v.26 no.2
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• pp.67-73
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• 2002

This study was done in order to evaluate the of effects on the blood lipid profiles, the body weight and body fat in 28 healthy female volunteers who had over 30% body fat by the long term intake of red ginseng product. Subjects were divided into four groups (placebo group n=7, red ginseng product group; n=7, exorcise group; n=7, exercise & red ginseng product group; n=7). Blood sampling and measuring of the body fat were taken by pre-treatment, 3 weeks, and after 12 weeks. Statistical techniques for data analysis were applied one-way ANOVA and repeated measures ANOVA. The 5% level of significance was used as the critical level for this study. In summary of results, total cholesterol, triglyceride and low density lipoproprotein cholesterol were reduced in three groups (red ginseng product group, p<0.001, exercise group, p<0.01 ; exercise & red ginseng product group, p<0.001) except placebo group. HDL-C was improved in three groups (red ginseng product group, p<0.05; exercise group, p<0.01; exercise & red ginseng product group, p<0.001) except placebo group. Body weight, percent body fat and body fat mass were reduced in three groups (red ginseng product group, p<0.01, exercise group, p<0.01 ; exercise & red ginseng product group, p<0.001) except placebo group. Finally, lean body mass was improved in three groups (red ginseng product group, p<0.05; exercise group, p<0.01; exercise & red ginseng product group, p<0.001) except placebo group.

• Korean Journal of Psychosomatic Medicine
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• v.24 no.2
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• pp.184-190
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• 2016

Objectives : This study analyzed the differences of body mass index(BMI) in Korean patients with Alzheimer's diseases(AD), Mild Cognitive Impairment(MCI), and healthy controls to verify whether low BMI is associated with cognitive impairment. Furthermore, this study also sought to examine any association between BMI and Mini Mental State Examination-Korean version(MMSE-K), Clinical Dementia Rating(CDR), and Global Deterioration Scale(GDS). Methods : A total of 257 subjects were included in the study. History taking, mental status examination, physical examination and neurocognitive function test were carried out for the diagnosis of AD and MCI. The subjects' demographic data and presence of diseases were also surveyed. The overall cognitive function and severity of diseases were assessed using MMSE-K, GDS, and CDR. Results : The order of BMI was found to be healthy controls>MCI>AD, with statistically significant differences among the groups. The order of MMSE-K scores was similar, with healthy controls>MCI>AD in statistically significant differences. The healthy controls had the lowest CDR and GDS scores, and AD patients had the highest scores. There was a significant positive correlation between BMI and MMSE scores(r=0.238, p=0.000). BMI was negatively correlated with CDR(r=-0.174, p=0.008) as well as with GDS(r=-0.233, p= 0.000). Conclusions : Measuring BMI of patients with AD or MCI is expected to be meaningful in that BMI could be a clinical indicator of AD. We expect this to be beneficial for the diagnosis, prevention, and therapeutic approach of AD and also expect large-scale, long-term longitudinal studies to follow.

• Journal of Wetlands Research
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• v.23 no.4
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• pp.317-326
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• 2021

The present study was carried out with a view to understand the distribution and ecology of Clihton retropictus (Martens, 1879), a class II endangered wildlife designated and protected by the Ministry of Environment, Republic of Korea, and to suggest the effective conservation and management measures for this species and its habit. First, the distribution of Clihton retropictus was investigated nationwide, and environmental factors such as salinity and substratum were analyzed in consideration of the ecological characteristics of this species. In addition, the individual size, density, and movement of Clihton retropictus per each district surveyed were analyzed. Due to its nature of inhabiting in the brackish water zone, the analysis showed that the salinity of this species was 0.7 ~ 16.6‰ at low tide and 1.0 ~ 17.3% at high tide. It was learned from the analysis of substratum that its composition in each river under investigation was slightly different, but most of substratum had a higher composition ratio than gravel (pebble, 16 ~ 64 mm). On the other hand, the size of each individual was checked by measuring the length of its diameter, and there was almost no change in the individual when the inhabited range of Clihton retropictus was short. However, there was tendency that the longer the habitat range, the bigger the individual size. From surveying the population density by season, it was made clear that, during the summer (July to August) and fall (September to October), the density was relatively higher while the number of individuals decreased significantly during winter (November to December) when the water temperature was lowered. In an effort to effectively establish conservation and management measures, the moving distance was measured, and it became known that, during the surveys in summer and fall when the individuals were active, the individuals moved in more distances than during the winter survey. The results of this study are expected to be utilized as basic data for establishing effective management plans such as creation of habitats for Clihton retropictus, its migration projects and selection of migration destinations which get unavoidable due to development projects.

• Journal of Family Resource Management and Policy Review
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• v.25 no.1
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• pp.15-34
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• 2021

Purpose : This study aims to identify the influence of individual, parental, workplace, and policy variables on the intention of marriage of unmarried workers. The results of the study can be used as a basis to come up with policy and practical measures to increase these workers' intention of marriage. Methods : Data was collected from 480 participants through a questionnaire. The measuring tools in this study were tested for reliability and validity. In addition, technical statistics, ANOVA, correlation analysis, and hierarchical regression analysis were performed by SPSS 18.0. Results : First, unmarried workers' willingness to marry was higher above the average. Second, significant differences in the unmarried workers' intention of marriage were revealed based on gender, age, level of education, total assets, and debt status. Significant associations were also found with parents' economic levels and the possibility of parental support for housing and marriage expenses. The differences in response based on employment patterns, job satisfaction, and family-friendly organizational culture were also significant. The correlation between policy variables and marriage intentions also showed the necessity of a funded housing policy and a marriage preparation policy. Third, based on the hierarchical regression analysis using personal, parental, and workplace variables to identify the factors affecting unmarried workers' willingness to marry, it is clear that gender, age, and the likelihood of parental support for housing and marriage expenses have a significant impact. A family-friendly organizational culture and funded housing policy were also significant contributors. Conclusion : The study found that the funded housing policy was the most important factor affecting unmarried office workers' willingness to marry. Additionally, the possibility of parental support for housing and marriage expenses and a family-friendly organizational culture at work were found to have an important impact on the improvement of unmarried workers' willingness to marry.

• Journal of IKEEE
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• v.25 no.3
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• pp.493-500
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• 2021

In this paper, we propose the development of deep learning structure to improve quality of polygonal containers. The deep learning structure consists of a convolution layer, a bottleneck layer, a fully connect layer, and a softmax layer. The convolution layer is a layer that obtains a feature image by performing a convolution 3x3 operation on the input image or the feature image of the previous layer with several feature filters. The bottleneck layer selects only the optimal features among the features on the feature image extracted through the convolution layer, reduces the channel to a convolution 1x1 ReLU, and performs a convolution 3x3 ReLU. The global average pooling operation performed after going through the bottleneck layer reduces the size of the feature image by selecting only the optimal features among the features of the feature image extracted through the convolution layer. The fully connect layer outputs the output data through 6 fully connect layers. The softmax layer multiplies and multiplies the value between the value of the input layer node and the target node to be calculated, and converts it into a value between 0 and 1 through an activation function. After the learning is completed, the recognition process classifies non-circular glass bottles by performing image acquisition using a camera, measuring position detection, and non-circular glass bottle classification using deep learning as in the learning process. In order to evaluate the performance of the deep learning structure to improve quality of polygonal containers, as a result of an experiment at an authorized testing institute, it was calculated to be at the same level as the world's highest level with 99% good/defective discrimination accuracy. Inspection time averaged 1.7 seconds, which was calculated within the operating time standards of production processes using non-circular machine vision systems. Therefore, the effectiveness of the performance of the deep learning structure to improve quality of polygonal containers proposed in this paper was proven.

• Korean Journal of Child Education & Care
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• v.19 no.2
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• pp.177-196
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• 2019

Objective: This study aims to analyze research trends related to software education for young children, focusing on studies published in Korea from 2016 to 2019 March. Methods: A total of 26 research publications on software education for young children, searched from Korea Citation Index and Research Information Sharing Service were identified for the analysis. The trend in these publications was classified and examined respectively by publication dates, types of publications, and the fields of study. To investigate a means of research, the analysis included key topics, types of research methods, and characteristics of the study variables. Results: The results of the analysis show that the number of publications on the topic of software education for young children has increased over the three years, of which most were published as a scholarly journal article. Among the 26 research studies analyzed, 16 (61.5%) are related to the field of early childhood education or child studies. Key topics and target subjects of the most research include the curriculum development of software education for young children or the effectiveness of software education on 4- and 5-year-old children. Most of the analyzed studies are experimental research designs or in the form of literature reviews. The most frequently studied research variable is young children's cognitive characteristics. For the studies that employ educational programs, the use of a physical computing environment is prevalent, and the most frequently used robot as a programming tool is "Albert". The duration of the program implementation varies, ranging from 5 weeks to 48 weeks. In the analyzed research studies, computational thinking is conceptualized as a problem-solving skill that can be improved by software education, and assessed by individual instruments measuring sub-factors of computational thinking. Conclusion/Implications: The present study reveals that, although the number of research publications in software education for young children has increased, the overall sufficiency of the accumulated research data and a variety of research methods are still lacking. An increased interest in software education for young children and more research activities in this area are needed to develop and implement developmentally appropriate software education programs in early childhood settings.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.19 no.1
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• pp.1-11
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• 2019

Purpose: Congenital hypothyroidism (CH) is the most common congenital endocrine disorder. The purpose of the present study was to determine the incidence of CH in South Korea during the period from January 1991 to March 2004. Methods: Central data from each city branch of SCL (Seoul Clinical Reference Laboratories) in Yongin, South Korea, was gathered and collectively analyzed. Newborn screening (NBS) for CH was based on measuring the levels of neonatal thyroid stimulating hormone (TSH) and free T4 (a cut-off of 20 mIU/L and less than 0.8 ng/dL, respectively). Results: During the study period, 671,805 live births were screened for CH based on TSH and free T4 ELISA assays. A total of 159 newborns were deemed positive for CH out of 671,805, with a corresponding incidence of 1 in 4,225. When a cut-off of 20 mIU/L was used in TSH assays, the associated sensitivity, specificity, and positive predictive values (PPV) were 100.0%, 99.7%, and 10.8%, respectively. When a cut-off of 0.8 ng/dL in free T4 assays was used, the associated sensitivity, specificity, and PPV were 100.0%, 98.5%, and 3.9%, respectively. Conclusion: CH incidence in South Korea as evidenced by the results of NBS was compared with its incidence and comparable to the other countries prior to 2004.