• Journal of Chest Surgery
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• v.32 no.4
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• pp.347-352
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• 1999

Background: The atrial fibrillation in patients with mitral valvular heart disease is frequently converted to sinus rhythm after the mitral valve surgery. This sinus restoration implies an important meaning in that it not only helps postoperative convalescence in patients with unstable hemodynamics but also reduces the rate of postoperative thromboembolism. Material and Method: We retrospectively analyzed 184 patients who received mitral valve surgery from June 1986 to December 1996 to investigate the trend of rhythm change following mitral valve surgery and thus to clarify the predisposing factors of postoperative sinus rhythm conversion and its maintenance. Result: The sinus rhythm was restored after the operation in 54 out of 139 patients with atrial fibrillation preoperatively(38.8%). However, the atrial fibrillation recurred in 41 patients at the time of discharge showing a recurrence rate of 75.9 percent. The mean duration of sinus rhythm in patients with eventual atrial fibrillation recurrence was 8.2${\pm}$5.9 days. Only 15 patients were in sinus rhythm at the time of late follow-up with the mean follow-up period of 84.4${\pm}$34.7 months. While the age, duration of symptoms, duration of atrial fibrillation, left atral size, and pulmonary artery pressure were thought to be the predisposing factors for sinus conversion after the operation, only the duration of atrial fibrillation and ejection fraction were considered risk factors for the recurrence of the atrial fibrillation following sinus conversion. Conclusion: This study suggests that the early operation is mandatory for the satisfactory result regarding postoperative rhythm. Moreover, additional operative measure in adjunct to the intervention of mitral valve should be considered for the maintenance of restored sinus rhythm as reflected by high postoperative recurrence rate of atrial fibrillation.

• The Journal of Korean Academy of Prosthodontics
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• v.58 no.3
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• pp.207-216
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• 2020

Purpose: To compare the polishing characteristics and their influence on Candida albicans adhesion to the recently introduced polyetherketoneketone (PEKK) and the conventional polymethylmethacrylate (PMMA) denture resin material. Materials and methods: Specimens from PEKK (Group E) and PMMA (Group M) were made in dimensions of 8 mm in diameter and 2 mm in thickness. The specimens were further divided into sub-groups according to the extent of polishing (ER, MR: rough; EP, MP: polished, N = 12 each). The specimens were polished using polishing machine and SiC foil. ER and MR group specimens were polished with 600 grit SiC foil only. EP and MP groups were further polished with 800, 1,000, 1,200 grit SiC foils sequentially. To measure the surface roughness values (Sa) of specimens, atomic force microscope (AFM) was used and scanning electron microscope (SEM) observation under 1,000, and 20,000 magnifications was performed to investigate surface topography. The polished specimens were soaked in C. albicans suspension for 2 hours with shaking to promote adhesion. The attached C. albicans were detached from the surface with 10 times of pipetting. The suspension of detached C. albicans was performed by serial dilution to 10³ times, and the diluted suspensions were inoculated on Sabouraud dextrose agar plates using spread plate method. After incubating the plate for 48 hours, colony forming unit (CFU)/plate of C. albicans was counted. Statistical analysis was performed using one-way ANOVA and Tukey HSD test to confirm significant difference between the groups (α=.05). Results: Average Sa value was significantly higher in MR group compared to other groups (P<.05), meaning that additional polishing steps reduced surface roughness effectively only in the PMMA specimens. There was no significant difference in Sa values between MP and EP groups. In SEM images, PEKK specimens showed numerous spikes of abraded material protruding from the surface and this phenomenon was more significant in EP group. The mean CFU/plate value was the highest in EP group and this was significant when it was compared to MP group (P<.05) which was the lowest. Conclusion: Polishing PEKK using serial SiC abrasive foil may result in higher adhesion of C. albicans. In clinic, this should be considered carefully.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.4
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• pp.228-234
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• 2004

In organic farming, nutrients for the crop production are mostly supplied by compost containing various organic materials. The long-term organic cultivation would result in continuous changes of soil chemical properties and fertility. The aim of this study was to investigate the contribution of long-term organic cultivation to the soil fertility in Korea focusing on the chemical properties of soil. Soil samples were collected from organic farms that had been cultivated for 8-10 years after certification of organic product through the conversion periods of 2-3 years. Thereby each organic farm had acquired optimal cultivating techniques and soil condition. We separated organic farms into three groups by cultivating crops, i.e. leaf vegetables, fruit vegetables and fruit trees. In each group, five representative farms were chosen in order to investigate the relationships between application rate of compost and nutrient contents in soil. The application rate of compost was approximately $10-15Mg\;10a^{-1}$ for the first 2-3 years at the beginning of organic farming and then reduced to a rate of $3-4Mg\;10a^{-1}$ after stabilization of organic matter content in soil with $30-50g\;10a^{-1}$. However, the continuous organic farming for 8-10 years resulted in accumulation of nutrients, especially of P, in soil probably due to the excessive amounts of compost applied. In conclusion, we suggest that the application rate and organic sources of compost should be decided on the basis of P content in soil by soil testing and thereafter the lack of soil N content for crop cultivation should be compensated by crop rotation with such as legumes. This might be an approach to the original meaning of organic farming as an environmental friendly agriculture.

• Korean journal of communication and information
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• v.33
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• pp.115-167
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• 2006

The purpose of this study was to investigate coverage patterns of the Korean internet news media on 'US-Iraq War' and its meaning and discourse structure. The internet news media was recently established and become a popular news media to compete with old news media in Korea. The author selected the 'Oh My News' as a representative internet news media for his analysis, and collected its news items from Mar. 20, 2003 to Dec. 17, 2003. on the basis of 4 different phases of the war. He analysed the whole of news items with various semiotic and discourse analytic methods, especially applying for Bell's concepts of time and discourse structure. As a result of this study, first of all, it was found that the 'Oh My News' tended to cover this war so different ways as the old news media did. It did not pay attention to the procedure of war, especially, battlefields, fighting between US and Iraq, damages and casualties. But, instead, it paid attention to many doubts about intention of US government and the President, Bush, dichotomous shift between pro-America and anti-America, rightness of dispatching Korean army into Iraq, etc. Secondly, it functioned as a kind of alternative media to speak up different voices comparing with those of old media. It tended to suggest different perspectives and opinions, while the old media tended to follow American perspectives and opinions. Thirdly, it became as a kind of new media setting agendas for this war in Korean society. It played a very important role for setting agendas for various issues related with this war. In conclusion, the internet news media has recently become a kind of new news media for suggesting alternative or different opinions, setting agendas, initiating discourses, etc., even though it still has may problems of becoming so called orthodox news media.

• Journal of the Korean earth science society
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• v.41 no.1
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• pp.19-30
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• 2020

To understand the impact of typhoons on Gamji gravel beach Taejongdae in Busan, we carried out beach profiling using a VRS-GPS system and a Drone photogrammetry for the typhoons 'Kong-rey' invaded in October 2018 and 'Danas' in July 2019. In addition, grain sizes are analyzed to investigate the overall distribution pattern of gravels on the beach, and the beach topography is surveyed periodically to confirm the recovery rate of the beach. Grain-size analysis reveals that mean gravel sizes, in general, become finer from -6.2Φ to -5.4Φ towards the east in the seashore line direction. Variation in mean sizes is obviously observed in the cross-shore direction. Gravels in the swash zone are relatively fine about -4.5Φ in size and equant in shape, whereas the coarse and oblate gravels ranged from -5Φ to -6Φ are found in the berm. Gamji gravel beach particularly has two lines of berms: a lower berm situated facing beach and an upper berm about 10 m landward. After the typhoon Kong-rey passed by, about 1.4 m of severe erosion in upper berm occurred, and the berm eventually disappeared. On the backshore of the upper berm about 50 cm of erosion took place so that the elevation became lower. However, tangible erosion was not observed in the lower berm. When typhoon Danas hit, rated as mild storm, both upper and lower berm were eroded out. However, about 50 cm of deposition occurred only in the backshore. Only three days later, the new lower berm was formed, meaning that sedimentation rate must be high. This result indicates that Gamji gravel beach is recovered very fast from erosion caused by the typhoons when it is under the fair-weather condition even though beach morphology changes dramatically in a short period of time. Gravel beach is estimated to be or evaluated very resilient to typhoon erosion.

• Journal of Internet Computing and Services
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• v.22 no.2
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• pp.109-121
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• 2021

As the global COVID-19 pandemic is prolonged, the Corona Blue phenomenon, combined with COVID-19 and blue, is intensifying. The purpose of this study is to analyze the current trend of Corona Blue in consideration of the possibility of increasing mental illness and the need for countermeasures, especially after COVID-19. This study tried to find out the relationship between stress and leisure activities before and after COVID-19 by using Corona Blue news article analysis through the topic modeling method, and questionnaire find out the help of stress and leisure activities. This study was compared and analyzed using two research methods. First, a total of 363 news articles were analyzed through topic modeling based on newspaper articles from January 2020, when COVID- 19 was upgraded to the "border" stage, until September, where the social distancing stage was strengthened to stage 2.5 in Korea. As a result of the study, a total of 28 topics were extracted, and similar topics were grouped into 7 groups: mental-demic, generational spread, causes of depression acceleration, increased fatigue, attitude to coping with long-term wars, changes in consumption, and efforts to overcome depression. Second, the SPSS statistical program was used to analyze the level of stress change according to leisure activities before/after COVID-19 and the main help according to leisure activities. As a result of the study, it was confirmed that the average difference in stress reduction according to participation in leisure activities before COVID-19 was larger than after COVID-19. Also, leisure activities were found to be effective in stress relief even after COVID-19. In addition, if the main help from leisure activities before COVID-19 was the meaning of relaxation and recharging through physical and social activities. After COVID-19, psychological roles such as mood swings through nature, outdoor activities, or intellectual activities were found to play a large part. As such, in this study, it was confirmed that understanding the current status of Corona Blue and coping with leisure in extreme stress situations has a positive effect. It is expected that this research can serve as a basis for preparing realistic and desirable leisure policies and countermeasures to overcome Corona Blue.

• The Journal of Korean Philosophical History
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• no.28
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• pp.267-296
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• 2010

There exists various advantages and disadvantages with various thoughts in human beings. Therefore, it causes very complicated conflict by these diversity. It would be impossible if there would not be solved in classes, areas, schools, cultures whether it is simple or complicated. The proposition which totally shows these logic are Cheng-Yi(程頤, 1033-1107)'s principle is one but its manifestations are many(理一分殊) and Yul-gok(栗谷, 1536-1584)'s all penetrating Li and defining Ch'i. The main concern is how to realize concretly the pure goodness in theory of principal and vital force. There are opinion which Li shows it's pure goodness initiatively and it only has to be shown through Ch'i. Toi-gyeo(退溪, 1501-1570)and Woo-dam(愚潭, 1625-1707) thought the subjectivity lies on Li which shows itself even though Li can't shows itself. On the while, Yul-gok thought it realize through Ch'i, and Li has the superintendence which Li shows itself through Ch'i. Regardless with above, Nok-mun(鹿門, 1711-1788) had the point of view which pure goodness come to realize by the coincidence of Li and Ch'i, on the same time, it didn't matter whether the subjectivity lay on Li or Ch'i, Li showed by nature while Ch'i did by vital energy controlled and worked together. While Yul-gok established his theoretical ground of universality in the best pure good and its bases on the realization, Woo-dam put an emphasis on the practice and realization of goodness to endow with its positive meaning. On the contrary of it, Nok-mun emphasised vital enerty, that is, enabled to realize goodness which premised Li and Ch'i are reciprocally related to other in non-segregated condition(理氣不相離). Still however, the most important thing is how the rightness can be concreately explained which human have to practice its pure goodness. It is not restricted on the Sung Confucianism, it is the material question in philosophy.

• The Korean Journal of Nuclear Medicine
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• v.30 no.4
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• pp.484-492
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• 1996

To detect ischemic tissue in experimental model of cerebral ischemia made by middle cerebral artery(MCA)-occlusion, we acquired triple image of $^{99m}Tc$-glucarate, [$^{18}F$]fluoro-deoxyglucose (FDG), and 2,3,5- triphenyltetrazolium (TTC) staining. We made cerebral infarction either with reperfusion (after occlusion of 2 hours) or without reperfusion in 10 Sprague-Dawley rats by inserting thread to MCA through internal carotid artery. After 22 hours, we injected 740 MBq of $^{99m}Tc$-glucarate and 55.5 MBq of [$^{18}F$]FDG through tail vein. Each 1 mm slice of rat brains was frozen and exposed to imaging plate for 20 minutes in freezer to get an [$^{18}F$]FDG image. After 20 hours enough to fade radioactivity of [$^{18}F$]FDG, the slices were again imaged by BAS1500 for $^{99m}Tc$-glucarate uptake. Finally, these brain tissues were stained with TTC. Semi-quantitative visual analysis was done by grading 0 to 3 points according to the degree of uptakes($^{99m}Tc$-glucarate) and decreased uptakes([$^{18}F$]FDG and TTC). Ten rats survived with neurologic symptoms. TTC staining confirmed the development of infarction. The size of the infarction was relatively larger in the group without reperfusion. [$^{18}F$]FDG images were similar to TTC-stained images. However, we found regions with intermediate uptake which were not stained with TTC. We found regions with intermediate [$^{18}F$]FDG uptake where TTC staining was normal. $^{99m}Tc$-glucarate uptake was round only in TTC non-stained region. In the TTC stained regions, there were no uptake of $^{99m}Tc$-glucarate. We could not find clear relation between $^{99m}Tc$-glucarate uptake with [$^{18}F$]FDG uptake. This was partly because percent uptake of $^{99m}Tc$-glucarate was so small (less than 1 percent of injected dose) and because there were quite heterogeneity of patterns of [$^{18}F$]FDG uptake and TTC. With these findings, we could conclude that $^{99m}Tc$-glucarate were taken up only in part of ischemic tissues which were proven to be nonviable. The establishment of MCA-occluded rat model with or without reperfusion and triple imaging for $^{99m}Tc,\;^{18}F$ and TTC helped the characterization of $^{99m}Tc$-glucarate uptakes. Further work is needed to clarify the meaning or diversities or [$^{18}F$]FDG and TTC and their relation with $^{99m}Tc$-glucarate.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.11
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• pp.1580-1586
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• 2009

This study is on the effect of oil seed by-products added to Chungkukjang. For this, we designed three cases: Chungkukjang was added in with defatted sesame flour before fermented (DSFBF), added with defatted sesame flour after fermented (DSFAF) and with no adding (control). In each case, the common ingredients and the active antioxidant ingredients were examined and compared and the effects were analyzed. According to microanalysis result, carbohydrate content Chungkukjang the DSFAF 24.97%, control 23.86%, DSFBF Chungkukjang 20.21% as compared to control and Chungkukjang DSFAF relatively low carbohydrate content. The moisture contents in DSFBF (55.98%) or DSFAF (52.83%) were higher than that in control (48.89%). Chungkukjang crude ashes in DSFBF (1.48%) or DSFAF (2.41%) were much lower than in control (6.45%). The proportions of crude lipid in DSFBF (3.30%) or DSFAF (3.93%) were higher than in control (1.77%) by about 2%. As for crude protein, the percentage in DSFAF (15.86%) was lower than that of DSFBF (19.03%) or of control (19.03%). There was no meaningful difference in biological activity measurement as total phenolic contents were 1.26 mg/mL in DSFBF, 1.14 mg/mL in DSFAF and 1.26 mg/mL in control. But electron donating ability was meaningfully more active in DSFBF (21.30%) than in control (20.24%). The superoxide dismutase (SOD)-like activity in DSFBF (68.48%) was twice higher than in control (34.01%), which may imply that DSFBF contain some ingredients that can scavenge superoxide anion radically. In hydroxyl radical scavenging activity, DSFAF scores 96.87%, which is the highest with 96.40% in DSFBF and 95.73% in control. Relative antioxidative effects in DSFBF was 47.92%, which is comparable to 47.06% in control. As a result of extraction and quantitative HPLC analysis of sesamin and sesamolin extracted from the samples, DSFBF contained 3.04$\pm$0.21 mg/g of sesamin, which is meaningfully higher than 2.41$\pm$0.14 mg/g in DSFAF. Content of sesamolin was higher in DSFBF (1.36$\pm$0.09 mg/g) than DSFAF (1.12$\pm$0.07 mg/g) or in control. We can conclude that biologically active and effective ingredients could be found more in DSFBF than in DSFAF or in control. This study conveys not only the meaning that oil seed by-products can be used as an ingredient for making Chungkukjang functional food, but also the possibility that oil seed by-products themselves could become excellent functional food.

• Journal of Intelligence and Information Systems
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• v.28 no.4
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• pp.251-273
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• 2022

Recently, research on applying text analysis to deep learning has steadily continued. In particular, researches have been actively conducted to understand the meaning of words and perform tasks such as summarization and sentiment classification through a pre-trained language model that learns large datasets. However, existing pre-trained language models show limitations in that they do not understand specific domains well. Therefore, in recent years, the flow of research has shifted toward creating a language model specialized for a particular domain. Domain-specific pre-trained language models allow the model to understand the knowledge of a particular domain better and reveal performance improvements on various tasks in the field. However, domain-specific further pre-training is expensive to acquire corpus data of the target domain. Furthermore, many cases have reported that performance improvement after further pre-training is insignificant in some domains. As such, it is difficult to decide to develop a domain-specific pre-trained language model, while it is not clear whether the performance will be improved dramatically. In this paper, we present a way to proactively check the expected performance improvement by further pre-training in a domain before actually performing further pre-training. Specifically, after selecting three domains, we measured the increase in classification accuracy through further pre-training in each domain. We also developed and presented new indicators to estimate the specificity of the domain based on the normalized frequency of the keywords used in each domain. Finally, we conducted classification using a pre-trained language model and a domain-specific pre-trained language model of three domains. As a result, we confirmed that the higher the domain specificity index, the higher the performance improvement through further pre-training.