• Bulletin of the Korean Chemical Society
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• v.20 no.3
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• pp.341-344
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• 1999

The hydrazones of 2-acetylfuran, 2-acetylthiophene, and 2-acetylpyrrole, were allowed to react with S-methylthioacetimidate hydroiodide (8) to give azinoureas 10, and the reaction of 10 with Appel's dehydration conditions (triphenylphosphine/carbon tetrachloride/triethylamine) led to the corresponding azinocarbodiimides 11, which underwent thermal rearrangement under the reaction conditions to give 1,1-diheteroaryl ethylenes 13.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.04a
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• pp.868-869
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• 2010

본 논문은 행렬 분해 기법인 SVD를 이용하여 블로그 공간을 분석한다. 분석 결과 블로그 공간에서 커뮤니티들을 발견했고, 각 커뮤니티에 속한 영향력 있는 블로그와 포스트를 발견했다.

• KIPS Transactions on Software and Data Engineering
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• v.11 no.4
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• pp.149-156
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• 2022

In the current COVID-19 pandemic, fake news and misinformation related to COVID-19 have been causing serious confusion in our society. To accurately detect such fake news, social context-based methods have been widely studied in the literature. They detect fake news based on the social context that indicates how a news article is propagated over social media (e.g., Twitter). Most existing COVID-19 related datasets gathered for fake news detection, however, contain only the news content information, but not its social context information. In this case, the social context-based detection methods cannot be applied, which could be a big obstacle in the fake news detection research. To address this issue, in this work, we collect from Twitter the social context information based on CoAID, which is a COVID-19 news content dataset built for fake news detection, thereby building CoAID⁺ that includes both the news content information and its social context information. The CoAID⁺ dataset can be utilized in a variety of methods for social context-based fake news detection, thus would help revitalize the fake news detection research area. Finally, through a comprehensive analysis of the CoAID⁺ dataset in various perspectives, we present some interesting features capable of differentiating real and fake news.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.1
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• pp.79-94
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• 2022

The demand for tunnel construction is increasing as part of underground space development due to urban saturation. The shield TBM method minimizes vibration and noise and minimizes ground deformation that occurs simultaneously with excavation, and shield TBM is generally applied to tunnel construction in urban areas. The importance of urban ground settlement prediction is increasing day by day, and in the case of shield TBM construction, ground deformation is minimized, but ground settlement due to tunnel excavation inevitably occurs. Therefore, in this study, the correlation between shield TBM, which is highly applicable to urban areas, and ground settlement is analyzed to suggest the shield TBM construction factors that have a major effect on ground settlement. Correlation analysis was performed between the shield TBM construction data and ground settlement measurement data collected at the actual site, and the degree of correlation was expressed as a correlation coefficient "r". As a result, the main construction factors of shield TBM affecting ground settlement were thrust force, torque, chamber pressure, backfill pressure and muck discharge. Based on the results of this study, it is expected to contribute to the presentation of judgment criteria for major construction data so that the ground settlement can be predicted and controlled in advance when operating the shield TBM in the future.

• Journal of The Korean Society of Clinical Toxicology
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• v.20 no.2
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• pp.66-74
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• 2022

Purpose: This study investigates the characteristics and prognosis of acute poisoning patients visiting nationwide emergency departments before and after the Coronavirus disease 2019 (COVID-19) pandemic. Data were obtained from the National Emergency Department Information System (NEDIS). Methods: This nationwide retrospective observational study included acute poisoning patients who visited the emergency departments between February 1 to December 31, 2020, which has been determined as the pandemic period. The same periods in 2018 and 2019 were designated as the control periods. The primary outcome assessed was the length of stay in emergency departments (EDLOS). The secondary outcomes examined were intensive care unit admission rate and in-hospital mortality rate before and after the pandemic. A subgroup analysis was performed for inpatients and intentional poisoning patients. Results: A total of 163,560 patients were included in the study. During the pandemic, the proportion of women increased from 50.0% in 2018 and 50.3% in 2019 to 52.5% in 2020. Patients aged 20-29 years increased from 13.4% in 2018 and 13.9% in 2019 to 16.6% in 2020. A rise in cases of intentional poisoning was also noted - from 33.9% in 2018 and 34.0% in 2019 to 38.4% in 2020. Evaluating the hospitalized poisoned patients revealed that the EDLOS increased from 3.8 hours in 2018 and 3.7 hours in 2019 to 4.2 hours in 2020. ICU admissions were also markedly increased (2018, 48.2%; 2019, 51.8%; 2020, 53.2%) among hospitalized patients. Conclusion: The COVID-19 pandemic has changed the epidemiology, clinical characteristics, and prognosis of acute poisoning patients visiting nationwide emergency departments in Korea. The proportion of young adults, women, and intentional poisoning patients has increased after the COVID-19 pandemic. Prolonged length of stay at the emergency department and an increased rate of intensive care unit admissions were determined in hospitalized acute poisoning patients.

• Journal of the Korean Society of Radiology
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• v.81 no.5
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• pp.1184-1193
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• 2020

Purpose This study was performed to evaluate the relationship between callosal microbleeds and anoxic brain injury. Materials and Methods Twenty-seven patients with anoxic brain injuries were analyzed and retrospectively compared to the control group of patients without a history of anoxic brain injury using Fisher's exact test regarding comorbidities and cerebral microbleeds. The patient group was subdivided according to the presence of callosal microbleeds. Fisher's exact test was used to compare the presence of typical MRI findings of anoxic brain injury, use of cardiopulmonary resuscitation, and prognosis. The Mann-Whitney U test was used to compare the interval between the occurrence of anoxic brain injury to MRI acquisition. Results The prevalence of cerebral microbleeds in the patient group was 29.6%, which was significantly higher than that in the control group at 3.7% (p = 0.012). All cerebral microbleeds in the patient group were in the corpus callosum. Compared with the callosal microbleed-absent group, the callosal microbleed-present group showed a tendency of good prognosis (6/8 vs. 11/19), fewer typical MRI findings of anoxic brain injury (2/8 vs. 10/19), and more cardiopulmonary resuscitation (6/8 vs. 12/19), although these differences did not reach statistical significance (p = 0.35, p = 0.19, and p = 0.45, respectively). Conclusion Callosal microbleeds may be an adjunctive MRI marker for anoxic brain injury.

• Bulletin of the Korean Space Science Society
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• 2009.10a
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• pp.30.3-31
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• 2009

"칠정산 외편"은 태양 태음 오성의 운행, 교식(交食), 태음오성능범(太陰五星凌犯) 등의 천문 현상을 추보하는 데 필요한 표(입성)[立成]와 계산법을 수록한 역법서이다. 최근에 우리는 칠정산 외편의 일식과 일출입 계산의 전 과정을 전산화하였다. 잘 알려진 바와 같이, 관측지의 위도와 관련된 두 입성-"주야시 궁도분 입성"(晝夜時宮度分立成), "경위시 가감차 입성"(經緯時加減差立成)-의 계산 기준점은 중국의 난징이다. 위도와 관련이 없는 다른 입성들 역시 회회력에 수록된 것과 동일하다. 그러나 외편법으로 구한 합삭과 식심 시각은 난징이 아닌 한양의 지방시 시각이다. 이 역설을 해결할 단서는 달의 평균 황경, 즉 태음 중심행도(太陰中心行度) 계산에 쓰이는 보정 상수에 있다. 이론적인 보정값, 즉 외편법의 입성 조성 원리에 부합하는 보정값($243^{\circ}58'$)과 "외편"에 기록된 실제 보정값($243^{\circ}44'$)의 차이는 한양과 난징의 시차(時差)에 따른 달의 황경 증가량과 대략 일치한다. 한양 기준의 합삭 시각을 구하려면 "외편"에 기록된 보정값($243^{\circ}44'$)을 적용하여야 한다. 반면에 이론적인 보정값($243^{\circ}58'$)을 적용하면 합삭 시각이 난징의 지방시로 계산된다. 이 발표에서는 "칠정산 외편"의 역원(曆元)의 차이에 따른 보정 상수 중에서 태음과 관련된 상수 네 개가 모두 일정한 규칙에 따라 한양의 경도에 맞게 조정되었음을 밝힐 것이다. 아울러 태음중심 행도 보정값과 관련된 선행 연구의 오류들을 모두 바로잡고자 한다.

• Korean Journal of Metals and Materials
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• v.49 no.11
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• pp.868-873
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• 2011

In this study, the fabrication of ultra fine grained Mo bulk was conducted. $MoO_3$ nanopowders were prepared by a high energy ball-milling process and then reduced at the temperature of $800^{\circ}C$ without holding time in $H_2$ atmosphere. The particle size of Mo nanopowder was ~150 nm and grain size was ~40 nm. The two-step process was employed for the sintering of Mo nanopowder to obtain fine grain size. The densification over 90% could be obtained by the two-step sintering with a grain size of less than 660 nm. For higher density, modified two-step sintering was designed. 95% of theoretical density with the grain size of 730 nm was obtained by the modified two-step sintering.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.149-150
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• 2019

When concrete is exposed to fire, the decomposition of Portland cement paste results in critical damage to the concrete structure of a building. However the recovery process of the damaged concrete structure has not yet been fully elucidated. In addition, research on appropriate additives such as carbon nanotube (CNT) and nanosilica has been increasing recently, however, investigation of CNT and nanosilica incorporated cement paste after decomposition of CNT by high temperature is not fully investigated. In this study, we investigated the physicochemical properties of CNT incorporated cement paste under different temperatures ($200^{\circ}C$, $500^{\circ}C$ and $800^{\circ}C$). Also, the effects of different rehydration conditions ($20^{\circ}C$ 60% RH and in water for different curing times) on the recovery of the paste were studied. The changes in tensile strength, surface observation of the specimens were characterized. In addition, the decomposition and formation of hydrates in the paste due to the heating process were studied using X-ray diffraction. The results showed that incorporation of nanosilica enhanced tensile strength after heating to each target temperatures.

• Journal of KIBIM
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• v.11 no.3
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• pp.12-21
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• 2021

Existing real estate markets are monopolized because they are capital intensive and have information asymmetry. However, with the advent of the Fourth Industrial Revolution, technology is converging in various industries based on information technology (IT), and the real estate market is also developing a new field called "PropTech". According to this trend, new PropTech technologies are emerging in various real estate services sectors in Korea, but the electronic contract system, which accounts for the largest portion of the real estate industry, is still cited as a complex identification process and long processing time. Therefore, in this paper, we propose an improvement plan for the current electronic contract system through the introduction of blockchain technology, which is drawing attention with the development of PropTech, and explore the possibility of introduction by producing an experimental model of blockchain-applied electronic contract system in a programming language.