• The Mathematical Education
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• v.60 no.4
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• pp.451-466
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• 2021

The interaction between student and school levels should be considered to understand and examine equity in education. For this reason, we included the socioeconomic composition of schools to scrutinize the equity related to students' socioeconomic status and mathematical literacy in Korea. We applied the hierarchical linear modeling approach to the Programme for International Student Assessment (PISA) 2015 data for binational comparison between Korea (5,548 students from 168 schools) and the U.S. (5,217 students from 161 schools). The findings show that school-level achievement and the socioeconomic composition of schools cannot be ignored to understand Korean students' achievement gap between high and low socioeconomic status. In addition, U.S. students from low socioeconomic status were likely to have similar mathematics literacy scores. These findings indicated that inequity in Korean mathematics education could be intertwined with the characteristics of Korean students like high demands for supplementary private education and school characteristics like curriculum selection. This research also reminds mathematics educators that people should not simply mimic other education systems to resolve education issues in their own system.

• Animal Bioscience
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• v.35 no.8
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• pp.1223-1234
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• 2022

Objective: The objectives of this study were to evaluate the effects of daily feed intake during the laying period on embryonic myogenic differentiation 1 (MYOD1), myogenic factor 5 (MYF5), and myogenic factor 6 (MYF6) gene expression in genetically fat and lean lines of chickens. Methods: An experiment in a 2×2 factorial design was conducted with two dietary intake levels (100% and 75% of nutrition recommendation) and two broiler chicken lines (fat and lean). Two lines of hens (n = 384 for each line) at 23th week of age were randomly divided into 4 treatments with 12 replicates of 16 birds. The experiment started at 27th week of age (5% egg rate) and ended at 54th week of age. Hatched eggs from the medium laying period were collected. Real time polymerase chain reaction analysis was used to analyse the MYOD1, MYF5, and MYF6 mRNA levels of E7, E9, E11, E13, and E15 body tissues and E17, E19, and E21 chest and thigh muscle samples. Results: The results indicated that there were significant effects of line, dietary intake, and interactions between them on MYOD1, MYF5, and MYF6 gene mRNA expression levels in embryonic tissues. Low daily feed intake did not change the expression trend of MYOD1 mRNA in either line, but changed the peak values, especially in lean line. Low daily feed intake altered the trend in MYF5 mRNA expression level in both lines and apparently delayed its onset. There was no apparent effect of low daily feed intake on the trends of MYF6 mRNA expression levels in either line, but it significantly changed the values on many embryonic days. Conclusion: Maternal nutrient restriction affects myogenesis and is manifested in the expression of embryonic MYOD1, MYF5, and MYF6 genes. Long term selection for fat deposition in broiler chickens changes the pattern and intensity of myogenesis.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.5
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• pp.985-994
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• 2022

This study diagnoses the maturity level of local government's spatial information policy in the face of the digital transformation period. To this end, by using the stratification (AHP) analysis technique, for the spatial information expert group, the importance evaluation is performed along with the selection of measurement indicators of the level of spatial informatization. First, the current status and indicators in terms of spatial information policies of local governments are studied through theoretical considerations. In addition, by examining previous studies, differentiation from this study is presented. In this study, 3 indicators and 18 detailed items of spatial informatization level evaluation indicators could be selected. As a result of the evaluation, the overall importance ranking for the measurement index was 0.125 (12.5%) for the establishment and utilizations of GIS Systems provided by local governments, 0.109 (10.9%) for the quality management of basic spatial information, 0.107 (10.7%) for the establishment and utilization of its own spatial information. 0.073 (7.3%) for the collaboration and sharing within the institution, 0.071 (7.1%) for the operation of education and support system on spatial information, 0.065 (6.5%) for the securing a dedicated organization and professional human resources, and interest at the institutional level were derived in the order of 0.053 (5.3%). The results of this study are expected to be usefully utilized as basic data to evaluate the level of spatial information policies promoted by local governments. In addition, if the local government's spatial information policy is pursued centering on the major indicators derived from the study, it is expected that efficient policy operation will be possible.

• 한국노년학
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• v.40 no.3
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• pp.459-475
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• 2020

This study examined the moderating effect self-rated health has on the association between grandparenting and depressive symptoms. The fourth wave (in 2012) of the Korean Longitudinal Study of Ageing (KLoSA) was used for the analyses (N=650). The Coarsened Exact Matching (CEM) method was applied in order to ensure randomness in the selection of grandparents who participated in grandparenting and those who did not. The dependent variable was depressive symptoms, the independent variable was grandparenting, and the moderating variable was self-rated health. Control variables were education level, age, household income, gender, marital status and life satisfaction. After matching data by CEM, weighted multiple regression was applied with STATA 13.0. Also, simple slope analysis and region of significance were performed to interpret the interaction terms. The results showed that self-rated health had a significant moderating effect. Specifically, for grandparents with high self-rated health, grandparenting was associated with a lower level of depressive symptoms. On the contrary, for grandparents with low self-rated health, there was no difference depending on whether they participated in raising grandchildren. Based on these results, we discussed the need for consideration of self-rated health for grandparents who participated in grandparenting.

• 한국노년학
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• v.40 no.2
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• pp.239-255
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• 2020

The purpose of this study is to examine whether family relationships of elderly single-person households affect community participation and whether these relationships differ by gender. Based on Baltes and Baltes (1990) 's selection, optimization, and compensation theory (SOC) and the argument that family members are a social capital by Prandini (2014), we test whether family relationships can affect community participation in old age. In order to verify this, single-person households were extracted from the 2017 National Survey of Living Conditions and Welfare Needs conducted by the Korea Institute for Health and Social Affairs (Male sample=370, Female sample=1770), multiple regression analysis were conducted with the dependent variables of friends·neighbors and the participation at Kyungrodang·welfare centers for the elderly. The results are as follows. In the case of men, family relations showed no significant effect on their participation in friends·neighbors, or Kyungrodang·welfare centers. However, in the case of women, the frequency of contact with family had a positive effect on the frequency of meeting friends·neighbors. Family contact frequency and child relationship satisfaction had a positive (+) effect on Kyungrodang·welfare center participation, while family meeting frequency had a negative effect on participation in Kyungrodang·welfare centers. For women, although Prandini's (2014) claim that family members are a social capital seems to be supported, it was found that the impact could vary depending on the type of community participation. In addition, practical discussions and suggestions were presented.

• Korean Journal of Community Nutrition
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• v.27 no.3
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• pp.245-253
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• 2022

Objectives: This study was conducted to find out if the dietary iron intake of Koreans estimated by 2 different methods (iron content sources) using the food intake data from the Korea National Health and Nutrition Examination Survey (KNHANES) are comparable. One method was based on the KNHANES's Food & Nutrient Database (FND) derived mainly from the Korean Food Composition Table and the other used the iron content (IC) of food samples processed in the Korean Total Diet Study (KTDS). Methods: Dietary intake data from the 2013-2016 KNHANES was used to select representative foods (RFs) in KTDS for iron analysis. Selection of the RFs and cooking methods for each RF (RF × cooking method pair) was performed according to the 'Guidebook for Korean Total Diet Studies' and resulted in a total of 132 RFs and 224 'RF × cooking method' pairs. RFs were collected in 9 metropolitan cities nationwide once or twice (for those with seasonality) in 2018 and made into 6 composites each, based on the origin and season prior to cooking. Then, the RF composites prepared to a 'table ready' state for KTDS were analyzed by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). Dietary iron intake of the Korean population was estimated using only RFs' intake data based on the 2 sources of iron content, namely FND-KNHANES and IC-KTDS. Results: RFs in KTDS covered 92.0% of total food intake of Koreans in the 2016-2018 KNHANES. Mean iron intake of Koreans was 7.77 mg/person/day by IC-KTDS vs 9.73 mg/person/day by FND-KNHANES. The major food groups contributing to iron intake were meats (21.7%), vegetables (20.5%), and grains & cereals (13.4%) as per IC-KTDS. On the other hand, the latter source (FND-KNHANES) resulted in a very different profile: grains & cereals (31.1%), vegetables (16.8%), and meats (15.3%). While the top iron source was beef, accounting for 8.6% in the former, it was polished rice (19.2%) in the latter. There was a 10-fold difference in the iron content of polished rice between 2 sources that iron intakes excluding the contribution by polished rice resulted in very similar values: 7.58 mg/person/day by IC-KTDS and 7.86 mg/person/day by FND-KNHANES. Conclusions: This study revealed that the dietary iron intake estimated by 2 different methods were quite comparable, excluding one RF, namely polished rice. KTDS was thus proven to be a useful tool in estimating a 'closer-to-real' dietary intake of nutrients for Koreans and further research on various nutrients is warranted.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.2
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• pp.153-170
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• 2022

Waterjet has been comprehensively used in urban areas owing to a suitable technique for cutting concrete and rock, and low noise and vibration. Recently, the abrasive waterjet technique has been adopted and applied by the Korea Atomic Energy Research Institute to demolish concrete plugging without disturbing and damaging In-situ Demonstration of Engineered Barrier System in the disposal research tunnel. In this study, the use of abrasive waterjet in the tunnel was evaluated for practical applicability and the existing cutting model was compared with the experimental results. As a variable for waterjet cutting, multi-cutting, water flow rate, abrasive flow rate, and standoff distance were selected for the diversity of analysis. As regarding the practical application, the waterjet facilitated path selection for cutting the concrete plugging and prevented additional disturbances in the periphery. The pump's noise at idling was 64.9 dB which is satisfied with the noise regulatory standard, but it exceeded the standard at ejection to air and target concrete because the experiment was performed in the tunnel space. The experimental result showed that the error between the predicted and measured cutting volume was 12~13% for the first cut and 16% for second cut. The standoff distance had a significant influence on the cutting depth and width, and the error tended to decrease with decrement of standoff distance.

• The Journal of Internal Korean Medicine
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• v.43 no.4
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• pp.559-566
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• 2022

Introduction: The aim of this systematic review is to provide evidence confirming the efficacy and safety of herbal medicines used in the treatment of liver cancer. Methods: The review will include randomized clinical trials that compared herbal medicines used as treatments for liver cancer with other therapies, such as placebos and Western medicine. Only randomized controlled trials will be included in this review, and all types of herbal medicine will be evaluated. Eleven electronic databases will be searched from the inception date: the Cochrane Database of Systematic Reviews, MEDLINE, EMBASE, AMED, CINAHL, one Chinese database (CNKI), and five Korean databases (OASIS, DBpia, RISS, KISS, and NDSL). The selection of studies, data extraction, and management will be performed independently by four researchers. Methodological quality, including the risk of bias, will be assessed using the Cochrane risk-of-bias assessment tool. Results: The review of current evidence for the effectiveness of herbal medicine for liver cancer will be summarized and quantitatively analyzed. Conclusions: Our systematic review will provide evidence of the efficacy of herbal medicines as treatments for liver cancer. This evidence will provide useful information for practitioners and patients in the fields of oncology and complementary medicine.

• The Journal of the Korea Contents Association
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• v.22 no.9
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• pp.217-233
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• 2022

This study was conducted with the purpose of deriving a revitalization plan by analyzing the factors influencing the characteristics and perception of self-employment and self-employment selection of young people. To this end, discussions on self-employment and the size of workers were reviewed, and the characteristics, determinants, and difficulties of self-employment youth were analyzed based on data from a survey of youth in Seoul and Gyeonggi-do. The support plan proposed through the analysis should first strengthen the program so that the government, local governments, and schools can all gain experience in the practice of developing ideas, producing, and selling based on aptitude and competency to solve youth employment problems. Next, compared to support for technology-based start-ups, there are no suitable programs in the fields of knowledge, manufacturing, and distribution, and there is almost no support for freelancers in which the majority of young people are engaged. Therefore, it is necessary to diversify support projects so that the diversity of young people can be expressed in self-employment. Finally, it was found that entrepreneurship had an important influence on self-employment. However, Korean teenagers do not know what entrepreneurship is and have no experience in education, so they should focus on cultivating entrepreneurship in the regular curriculum and establishing a cultural foundation to foster young leaders with creative ideas and execution.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.27 no.2
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• pp.71-86
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• 2022

The water quality index (WQI) has been widely used to evaluate marine water quality. The WQI in Korea is categorized into five classes by marine environmental standards. But, the WQI calculation on huge datasets is a very complex and time-consuming process. In this regard, the current study proposed machine learning (ML) based models to predict WQI class by using water quality datasets. Sihwa Lake, one of specially-managed coastal zone, was selected as a modeling site. In this study, adaptive boosting (AdaBoost) and tree-based pipeline optimization (TPOT) algorithms were used to train models and each model performance was evaluated by metrics (accuracy, precision, F1, and Log loss) on classification. Before training, the feature importance and sensitivity analysis were conducted to find out the best input combination for each algorithm. The results proved that the bottom dissolved oxygen (DO_Bot) was the most important variable affecting model performance. Conversely, surface dissolved inorganic nitrogen (DIN_Sur) and dissolved inorganic phosphorus (DIP_Sur) had weaker effects on the prediction of WQI class. In addition, the performance varied over features including stations, seasons, and WQI classes by comparing spatio-temporal and class sensitivities of each best model. In conclusion, the modeling results showed that the TPOT algorithm has better performance rather than the AdaBoost algorithm without considering feature selection. Moreover, the WQI class for unknown water quality datasets could be surely predicted using the TPOT model trained with satisfactory training datasets.