• Journal of Korean Society of Forest Science
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• v.106 no.4
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• pp.431-440
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• 2017

The 2016 Gyeongju Earthquake ($M_L$ 5.8) (occurred on September 12, 2016) and the 2017 Pohang Earthquake ($M_L$ 5.4) (occurred on November 15, 2017) caused unprecedented damages in South Korea. It is necessary to establish basic data related to earthquake-induced mountainous sediment-related disasters over worldwide. In this study, we analyzed previous international studies on the earthquake-induced mountainous sediment-related disasters, then classified research areas according to research themes using text-mining and co-word analysis in VOSviewer program, and finally examined spatio-temporal research trends by research area. The result showed that the related-researches have been rapidly increased since 2005, which seems to be affected by recent large-scale earthquakes occurred in China, Taiwan and Japan. In addition, the research area related to mountainous sediment-related disasters induced by earthquakes was classified into four subjects: (i) mechanisms of disaster occurrence; (ii) rainfall parameters controlling disaster occurrence; (iii) prediction of potential disaster area using aerial and satellite photographs; and (iv) disaster risk mapping through the modeling of disaster occurrence. These research areas are considered to have a strong correlation with each other. On the threshold year (i.e., 2012-2013), when cumulative number of research papers was reached 50% of total research papers published since 1987, proportions per unit year of all research areas should increase. Especially, the proportion of the research areas related to prediction of potential disaster area using aerial and satellite photographs is highly increased compared to other three research areas. These trends are responsible for the rapidly increasing research papers with study sites in China, and the research papers examined in Taiwan, Japan, and the United States have also contributed to increases in all research areas. The results are could be used as basic data to present future research direction related to mountainous sediment-related disasters induced by earthquakes in South Korea.

• The Journal of the Convergence on Culture Technology
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• v.8 no.4
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• pp.163-171
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• 2022

This study was conducted to understand the research trends and central concepts of middle-aged women' health in Korea. For the analysis of this study, target papers published from 2012 to 2021 were collected by entering the keywords of 'middle-aged woman' or 'menopausal woman'. 1,116 papers were used for analysis. The co-occurrence network of key words was developed and analyzed, and the research trends were analyzed through topic modeling of the LSD by dividing it into five-year units (2012-2016, 2017-2021), and visualized word cloud and sociogram were used. The keywords that appeared the most during the last 10 years were obesity, depression, body composition, stress, and menopause symptom. Five topics analyzed in the thesis data for 5 years from 2012 to 2016 were 'postmenopausal self-efficacy and satisfaction enhancement strategy', 'exercise to manage obesity and risk factors', 'intervention for obesity and stress', 'promotion of happiness and life management' and 'menopausal depression and quality of life' were confirmed. Five topics of research conducted for the next five years (2017-2021) were 'menopausal depression and quality of life', 'management of obesity and cardiovascular risk factors', 'life experience as a middle-aged woman', and 'life satisfaction and psychological well-being' and 'menopausal symptom relief strategy'. Through the results, the trend of research topics related to middle-aged women's health over the past 10 years have been identified, and research on health of middle-aged women that reflects the trend of the future should be continued.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.4
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• pp.124-137
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• 2018

The main purpose of this study is to find the hotspots of crimes that occur frequently in the space and to derive the appropriate CCTV installation location. One of the characteristics of crime is clustered around past occurrence area, and these crimes are strongly correlated. It is also possible to find the cause of the clusters and the variables that affect the crime through the history of the crime. In addition to the traditional OLS model, spatial differential model including spatial autocorrelation and spatial error model were used to select the variables influencing the five major crime rate, the theft rate and the foreign resident rate. The variables affecting the Five major crimes were positive (+) sign for the welfare and the rate of the bar cluster rate, and negative (-) for the street density. The CCTV area occupies 46% of the hotspots based on the overlapping of the areas where the elderly people are crowded, the bar cluster, many multicultural families, and the areas with low density of street lamps. It turned out. Taking into account the current CCTV operation, the total number of new cases to cover the risk point was 89.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.1
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• pp.760-767
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• 2020

Sustainable growth of hydroelectric power plants is expected in consideration of climate change and energy security. However, hydroelectric power plants always have a risk of water hammer damage, and safety assurance is very important. The water hammer phenomenon commonly occurs during operations such as rapid opening and closing of the valves and pump/turbine shutdown in pipe systems, which is more common in cases of emergency shutdown. In this study, a computational numerical model was developed using the MOC-FDM scheme to reflect the mechanism of water hammer occurrence. The proposed model was implemented in boundary conditions such as reservoir, pipeline, valve, and pump/turbine conditions and then applied to simulate hypothetical case studies. The analysis results of the model were verified using the analysis results at the main points of the pipe systems. The model produced reasonably good performance and was validated by comparison with the results of the SIMSEN package model. The model could be used as an efficient tool for the safety assessment of hydroelectric power plants based on accurate prediction of transient behavior in the operation of hydropower facilities.

• Journal of the Korean Society for Library and Information Science
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• v.52 no.1
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• pp.341-357
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• 2018

Due to the paradigm of open science and advanced digital information technology, data sharing and re-use have been actively conducted and considered data-intensive in a wide variety of disciplines. This study aims to investigate the intellectual structure portrayed by the research products re-using the data sets from ICPSR. For the purpose of this study, a total of 570 research products published in 2017 from the ICPSR site were collected and analyzed in two folds. First, the authors and publications of those research products were analyzed in order to show the trends of research using ICPSR data. Authors tend to be affiliated with university or research institute in the United States. The subject areas of journals are recognized into Social Sciences, Health, and Psychology. In addition, a network with clustering analysis was conducted with using co-word occurrence from the titles of the research products. The results show that there are 12 clusters, mental health, tabocco effect, disorder in school, childhood, and adolescence, sexual risk, child injuries, physical activity, violent behavior, survey, family role, women, problem behavior, gender differences in research areas. The structure portrayed by ICPSR data re-uses demonstrates that substantial number of studies in Medicine have been conducted with a perspective of social sciences.

• Journal of Intelligence and Information Systems
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• v.25 no.3
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• pp.63-88
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• 2019

The goal of this paper is to investigate changes in North Korea's domestic and foreign policies through automated text analysis over North Korea represented in South Korean mass media. Based on that data, we then analyze the status of text mining research, using a text mining technique to find the topics, methods, and trends of text mining research. We also investigate the characteristics and method of analysis of the text mining techniques, confirmed by analysis of the data. In this study, R program was used to apply the text mining technique. R program is free software for statistical computing and graphics. Also, Text mining methods allow to highlight the most frequently used keywords in a paragraph of texts. One can create a word cloud, also referred as text cloud or tag cloud. This study proposes a procedure to find meaningful tendencies based on a combination of word cloud, and co-occurrence networks. This study aims to more objectively explore the images of North Korea represented in South Korean newspapers by quantitatively reviewing the patterns of language use related to North Korea from 2016. 11. 1 to 2019. 5. 23 newspaper big data. In this study, we divided into three periods considering recent inter - Korean relations. Before January 1, 2018, it was set as a Before Phase of Peace Building. From January 1, 2018 to February 24, 2019, we have set up a Peace Building Phase. The New Year's message of Kim Jong-un and the Olympics of Pyeong Chang formed an atmosphere of peace on the Korean peninsula. After the Hanoi Pease summit, the third period was the silence of the relationship between North Korea and the United States. Therefore, it was called Depression Phase of Peace Building. This study analyzes news articles related to North Korea of the Korea Press Foundation database(www.bigkinds.or.kr) through text mining, to investigate characteristics of the Kim Jong-un regime's South Korea policy and unification discourse. The main results of this study show that trends in the North Korean national policy agenda can be discovered based on clustering and visualization algorithms. In particular, it examines the changes in the international circumstances, domestic conflicts, the living conditions of North Korea, the South's Aid project for the North, the conflicts of the two Koreas, North Korean nuclear issue, and the North Korean refugee problem through the co-occurrence word analysis. It also offers an analysis of South Korean mentality toward North Korea in terms of the semantic prosody. In the Before Phase of Peace Building, the results of the analysis showed the order of 'Missiles', 'North Korea Nuclear', 'Diplomacy', 'Unification', and ' South-North Korean'. The results of Peace Building Phase are extracted the order of 'Panmunjom', 'Unification', 'North Korea Nuclear', 'Diplomacy', and 'Military'. The results of Depression Phase of Peace Building derived the order of 'North Korea Nuclear', 'North and South Korea', 'Missile', 'State Department', and 'International'. There are 16 words adopted in all three periods. The order is as follows: 'missile', 'North Korea Nuclear', 'Diplomacy', 'Unification', 'North and South Korea', 'Military', 'Kaesong Industrial Complex', 'Defense', 'Sanctions', 'Denuclearization', 'Peace', 'Exchange and Cooperation', and 'South Korea'. We expect that the results of this study will contribute to analyze the trends of news content of North Korea associated with North Korea's provocations. And future research on North Korean trends will be conducted based on the results of this study. We will continue to study the model development for North Korea risk measurement that can anticipate and respond to North Korea's behavior in advance. We expect that the text mining analysis method and the scientific data analysis technique will be applied to North Korea and unification research field. Through these academic studies, I hope to see a lot of studies that make important contributions to the nation.

• Research in Plant Disease
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• v.23 no.1
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• pp.75-81
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• 2017

In May 2016, 24 peach samples showing abnormal and virus like symptoms were collected in one of major peach producing area, Yeongcheon-si, Gyeongsangbuk-do, Korea. We performed RT-PCR diagnosis for confirmation of viral infection. The diagnostic targets are 17 species of viruses and viroids that quarantine and high risk pathogens when it occur. As a results, seven species of viruses and viroids, including an unreported (Apricot pseudo-chlorotic leaf spot virus, APCLSV) and a quarantine (Peach latent mosaic viroid, PLMVd) species in Korea, were detected. For the sequence analysis of unreported virus, APCLSV, the sequence of coat protein gene were amplified and cloned. The sequence showed 97% nucleotide identity with other APCLSV isolates and compared with other seven species of reported Trichoviruses. This virus was classified as APCLSV based on the sequence and phylogenetic analysis. This isolate was named Yeongcheon. As patterns of APCLSV occurrence, all samples that APCLSV detected were co-infected with Apple chlorotic leaf spot virus (ACLSV). As properties of ACLSV, APCLSV has high possibility of wide spread disease in fruit tree farms in Korea. Therefore, it is necessary to do related researches, such as infection route and influence of disease in commercial orchards.

• Korean Journal of Environmental Biology
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• v.37 no.4
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• pp.759-768
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• 2019

This study was conducted to estimate the mean annual extreme minimum temperature raster and predict the potential distribution of the invasive plant, Ipomoea triloba, on the Korean peninsula. We collected annual extreme minimum temperature and mean coldest month minimum temperature data from 129 weather stations on the Korean peninsula from 1990-2019 and used this data to create a linear regression model. The min temperature of the coldest month raster from Worldclim V2 were used to estimate a 30 second spatial resolution, mean annual extreme minimum temperature raster of the Korean peninsula using a regression model. We created three climatic rasters of the Korean peninsula for use with the Proto3 species distribution model and input the estimated mean annual extreme minimum temperature raster, a Köppen-Geiger climate class raster from Beck et al. (2018), and we also used the mean annual precipitation from Worldclim V2. The potential distribution of I. triloba was estimated using the Proto3 model with 117 occurrence points. As a result, the estimated area for a potential distribution of I. triloba was found to be 50.7% (111,969 ㎢) of the Korean peninsula.

• Clinical and Experimental Reproductive Medicine
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• v.30 no.4
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• pp.333-340
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• 2003

Objective: This study was performed to examine the maturation and the development to the blastocyst stage of immature oocytes collected from patients with high risk of ovarian hyperstimulation syndrome (OHSS). Materials and Methods: Cumulus-oocyte complexes (COCs) were collected following only HCGpriming for non stimulated IVF-ET cycles of the patients. At the time of oocyte collection, COCs were classified into three groups in accordance with their appearance (Group I: oocytes with dispersed cumulus cells; Group II: oocytes with compacted cumulus cells; Group III: oocytes with sparse cumulus cells). The in vitro maturation and blastocyst development rates of the COCs were compared among these groups. From August 2001 to June 2002, 48 IVM/IVF-ET cycles from 42 patients (mean age: $32.4{\pm}3.8$ years) were performed. To prevent the occurrence of OHSS, the patients were primed with 10, 000 IU HCG alone 36 h before oocyte collection without gonadotropin stimulation. Oocytes were aspirated on cycle days from 7 to 13. The normal COCs were classified into three groups according to their appearance. The aspirated immature oocytes were cultured in YS maturation medium containing 30% (v/v) human follicular fluid (HFF), 1 IU/ml FSH, 10 IU/ml HCG and 10 ng/ml rhEGF. Fertilization was induced by intracytoplasmic sperm injection (ICSI). All zygotes were co-cultured with cumulus cells in $10{\mu}l$ YS medium containing 10% HFF until day 7 after oocyte collection. Blastocyst transfer was performed on day 5 after ICSI. Results: Th e mean number of oocytes cultured in the IVM/IVF cycles was $24.7{\pm}10.6$. Of 1185 COCs, those assigned to Group I, II and III were 470 (39.7%), 414 (35.0%) and 301 (25.4%), respectively. The maturation rate (94.5%, 444/470, p<0.05) in Group I was significantly higher than those of Group II (62.8%, 260/414) and Group III (73.1%, 220/301). Especially, 30.9% of COCs in Group I (145/470) was matured on the day of oocyte aspiration. There were no differences in the rates of fertilization and cleavage among the three groups. The development rate to the blastocyst stage in Group I (54.6%, 206/377, p<0.05) was also significantly higher than those in Group II (33.0%, 68/206) and Group III (30.1%, 52/173). Twenty-four clinical pregnancies (50.0%) was obtained and 22 pregnancies (45.8%) are ongoing. Implantation rate in the present study was 24.6%. Conclusion: These results suggest that there is a positive correlation between the appearance of COCs and the developmental competence of the immature oocytes in non stimulated IVM/IVF cycles.

• Journal of the Korean Geotechnical Society
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• v.38 no.4
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• pp.59-70
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• 2022

There is a growing interest in evaluating earthquake damage and determining disaster prevention measures due to the magnitude 5.8 earthquake in Pohang, Korea. Since the liquefaction phenomena occurred extensively in the residential area as a result of the earthquake, there was a demand for research on liquefaction phenomenon evaluation and liquefaction disaster prediction. Liquefaction is defined as a phenomenon where the strength of the ground is completely lost due to a sudden increase in excess pore water pressure caused due to large dynamic stress, such as an earthquake, acting on loose sand particles in a short period of time. The liquefaction potential index, which can identify the occurrence of liquefaction and predict the risk of liquefaction in a targeted area, can be used to create a liquefaction hazard map. However, since liquefaction assessment using existing field testing is predicated on a single borehole liquefaction assessment, there has been a representative issue for the whole targeted area. Spatial interpolation and geographic information systems can help to solve this issue to some extent. Therefore, in order to solve the representative problem of geotechnical information, this research uses the kriging method, one of the geostatistical spatial interpolation techniques, and constructs a geotechnical information database for liquefaction and spatial interpolation. Additionally, the liquefaction hazard map was created for each return period using the constructed geotechnical information database. Cross validation was used to confirm the accuracy of this liquefaction hazard map.