• The Korean Journal of Applied Statistics
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• v.33 no.6
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• pp.777-789
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• 2020

COVID-19 has been rapidly spread world wide since late December 2019. In this paper, our interest is to estimate distribution of incubation time defined as period between infection of virus and the onset. Due to the limit of accessibility and asymptomatic feature of COVID-19 virus, the exact infection and onset time are not always observable. For estimation of incubation time, interval censoring technique is implemented. Furthermore, a competing risk model is applied to estimate the case fatality and cure fraction. Based on the result, the mean incubation time is about 5.4 days and the fatality rate is higher for older and male patient and the cure rate is higher at younger,female and asymptomatic patient.

• Journal of the Korea Institute of Construction Safety
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• v.4 no.1
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• pp.16-21
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• 2021

Recently, as part of an effort to reduce the high accident rate in the construction industry, the smart construction safety technology is being introduced, and some institutional improvements are being made simultaneously. This study has been carried out to identify the effectiveness of such an improved institution and to draw additional opinions for improvement to spread the field application of smart safety technology. A survey was conducted for participants in the construction industry, and awareness of the improved institution and additional requirements for spreading smart safety technology in the construction site were investigated. As a result of the investigation, high interest in the field application of smart construction safety technology has been confirmed, and some issues such as safety management costs and duplication of on-site safety paperwork have been raised. The opinions derived through this study will be used as baseline data for future institutional improvements for the introduction and diffusion of smart construction safety technology in the construction site.

• The Korean Journal of Financial Management
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• v.27 no.1
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• pp.181-208
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• 2010

In July 2007, Korean government has passed "The Capital Market and Financial Investment Services Act" to further develop the capital markets and the Act was to become effective in February 2009. Using a large sample of Korean firms, we have examined (i) the effect of underwriting activities on the firm value (bond spread) comparing commercial bank and investment bank, and (ii) the determinants of the firm value changes following underwriting activities of bank. To test our goal, we collected a wide range of samples of data for bond issuing activities executed by Korean firms listed on the Korea Stock Exchange (KSE) between 2000 and 2003. Our paper is distinguished from previous studies on this subject in a way that we analyzed the effect of corporate bond underwriting activities with regard to commercial banking and investment banking. Initially, we set up a hypothesis that "Certification View" and "Conflict-of-interest View" are major driving forces behind cross-firm differences in performance following bond issuance. We find that, in general, underwriting by investment bank (securities company) brings a positive effect on the firm value (spread between bench mark rate and bond issuing rate). This result indicates that firm value has been negatively affected by the bank underwriting and provides the evidence for "Conflict-of-interest View" in Korea. Our studies have also revealed that any change in firm value following bond issuance is positively related with the firm size (total asset), operating performance, liquidity (cashflow), and equity ownership by foreign investors. Overall, our results support the view that bank underwriting activities can play an important role in determining firm value and financial strategies under "The Capital Market and Financial Investment Services Act" of 2007.

• Journal of Biomedical Engineering Research
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• v.44 no.6
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• pp.363-376
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• 2023

According to the COVID-19, development of various medical software based on IoT(Internet of Things) was accelerated. Especially, interest in a central software system that can remotely monitor and control ventilators is increasing to solve problems related to the continuous increase in severe COVID-19 patients. Since medical device software is closely related to human life, this study aims to develop central monitoring system that can remotely monitor and control multiple ventilators in compliance with medical device software development standards and to verify performance of system. In addition, to ensure the safety and reliability of this central monitoring system, this study also specifies risk management requirements that can identify hazardous situations and evaluate potential hazards and confirms the implementation of cybersecurity to protect against potential cyber threats, which can have serious consequences for patient safety. As a result, we obtained medical device software manufacturing certificates from MFDS(Ministry of Food and Drug Safety) through technical documents about performance verification, risk management and cybersecurity application.The purpose of this study is to conduct a usability assessment to ensure that ergonomic design has been applied so that the ventilator central monitoring system can improve user satisfaction, efficiency, and safety. The rapid spread of COVID-19, which began in 2019, caused significant damage global medical system. In this situation, the need for a system to monitor multiple patients with ventilators was highlighted as a solution for various problems. Since medical device software is closely related to human life, ensuring their safety and satisfaction is important before their actual deployment in the field. In this study, a total of 21 participants consisting of respiratory staffs conducted usability test according to the use scenarios in the simulated use environment. Nine use scenarios were conducted to derive an average task success rate and opinions on user interface were collected through five-point Likert scale satisfaction evaluation and questionnaire. Participants conducted a total of nine use scenario tasks with an average success rate of 93% and five-point Likert scale satisfaction survey showed a high satisfaction result of 4.7 points on average. Users evaluated that the device would be useful for effectively managing multiple patients with ventilators. However, improvements are required for interfaces associated with task that do not exceed the threshold for task success rate. In addition, even medical devices with sufficient safety and efficiency cannot guarantee absolute safety, so it is suggested to continuously evaluate user feedback even after introducing them to the actual site.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.4
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• pp.480-488
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• 2016

As the subprime mortgage crisis spread globally, it depressed not only the financial market, but also the construction business in Korea. In fact, according to CERIK, the BSI of the construction businesses plunged from 80 points in December 2006 to 14.6 points in November 2008, and the extent of the depression in the housing sector was particularly serious. In this respect, this paper analyzes the influence of the financial market fluctuation on the housing market before and after the Global Financial Crisis using VECM. The periods from January 2000 to December 2007 and January 2008 to October 2015, before and after the financial crisis, were set as Models 1 and 2, respectively. The results are as follows. First, when the economy is good, the Gangnam housing market is an attractive one for investment. However, when it is depressed, the Gangnam housing market changes in response to the macroeconomic fluctuations. Second, the Gangbuk and Gangnam housing markets showed different responses to fluctuations in the financial market. Third, when the economy is bad, the effect of low interest rates is limited, due to the housing market risk.

• IMMUNE NETWORK
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• v.21 no.6
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• pp.38.1-38.8
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• 2021

Recently, a new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (B.1.1.529) Omicron variant originated from South Africa in the middle of November 2021. SARS-CoV-2 is also called coronavirus disease 2019 (COVID-19) since SARS-CoV-2 is the causative agent of COVID-19. Several studies already suggested that the SARS-CoV-2 Omicron variant would be the fastest transmissible variant compared to the previous 10 SARS-CoV-2 variants of concern, interest, and alert. Few clinical studies reported the high transmissibility of the Omicron variant but there is insufficient time to perform actual experiments to prove it, since the spread is so fast. We analyzed the SARS-CoV-2 Omicron variant, which revealed a very high rate of mutation at amino acid residues that interact with angiostatin-converting enzyme 2. The mutation rate of COVID-19 is faster than what we prepared vaccine program, antibody therapy, lockdown, and quarantine against COVID-19 so far. Thus, it is necessary to find better strategies to overcome the current crisis of COVID-19 pandemic.

• Journal of Digital Convergence
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• v.13 no.8
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• pp.235-243
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• 2015

Recently, due to the spread of the Korean Wave, as worldwide interest in Korean culture and the appearance of Korean celebrities increases, overseas expansion of Korean beauty companies have been activated. Despite the global economic downturn, Beauty Industry is continuing to grow, Korea's growth rate is remarkable level. Despite this growth in order to maintain a steady growth since the beauty industry is small and polarization based on the Beauty-IT Convergence Technology creates new markets, that require development of Beauty-IT Convergence Industry. For the status and prospects of the Beauty Industry, some research has been carried out, not all the studies carried out so far for Beauty-IT Convergence Industry. Therefore, this study is significant that Beauty-IT Convergence Industry's first research. The global Beauty-IT Convergence Industry is at the beginning yet, tThe government selected research topics of Top-Down approach to Beauty-IT Convergence technology, granted extra points, supported by establishing long-term Technology Roadmap as other industries, such as by establishing a global market strategy for the systematic occupation and promising technology development planWe will get focused training.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.20 no.6
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• pp.117-131
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• 2017

This study was conducted to draw vegetation landscape elements in the ancient literature, investigate plant community structure, understand vegetation structure, and suggest reasonal conservation management methods. As a result of analyzing ancient literature, geomorphological landscapes in Guryong valley were canyon landscape and valley surrounded in Mt. Chiak. Plant landscape factors were as followed. Rhododendron spp. spread around valley. Also, Pinus densiflora communities were distributed in Guryong valley around. Especially, the entrance zones of Guryong valley were described as covered with Pinus densiflora and Whangchangkumpyo(黃腸禁標). Therefore, it was estimated that entry of Guryong valley was covered with Pinus densiflora community landscape. As for current vegetation result, the main vegetation was divided into mixed deciduous broad-leaved trees community and Pinus densiflora community. As a result of analysis by TWINSPAN for community classification, five communities(Deciduous broadleaved trees, Pinus densiflora, Pinus densiflora-Abies holophylla, Abies holophylla, and Pinus koraiensis community) were classified. To maintain historic plant landscape and conserve crucial resources, Pinus densiflora community was classified as concentrated conservation management area($105,472m^2$). To maintain Pinus densiflora landscape which has high historical and cultural value of Guryong valley, it was considered that active density control of lower layer vegetation would be necessary. Accordingly, to conserve P. densiflora landscape, Whangchangkumpyo(?腸禁標), that area was separated into Pinus densiflora lower layer forest management area($84,029m^2$) and Pinus densiflora seedling conservation management area($21,443m^2$). In understory of Pinus densiflora lower layer flora, the target tree species for elimination and management were Quercus serrata and Quercus mongolica. They were $4{\sim}6trees/100m^2$ and their average diameter was 7.1cm. To preserve Pinus densiflora seedlings, areas with Sasa borealis, the ground vegetation of Pinus densiflora community, rate of 80% or more should be selected as priority management areas and concentrated elimination and management of Sasa borealis should be implemented. Likewise, traditional Pinus densiflora forest is a historically cultural heritage to preserve with sustainable interest and survey. Efficient management method through systematic monitoring system should be made.

• The Journal of Korean Association of Computer Education
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• v.16 no.3
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• pp.49-60
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• 2013

This study is aimed to investigate that the blended e-learning could enhance the effectiveness compared to the conventional lecture performed in classroom. At first, both the CbE(Class based E-learning) and the EbC(E-learning based Class) mode have been generated in blended e-learning operation method following the process which analyze the various studies of interest. In addition, the instruction structures of Z Type(Zigzag model) and H-Type(Ladder model) were established as proposed model. The H-Blended e-learning based on CbE mode was introduced in the Excel Spread Sheet subject which held in A University to achieve the goal of this study. Learners were categorized and belonged to either the group 1(over 50% of attendance in cyber lecture) or the group 2(the rest of them). The data analysis was performed with $x^2$-test, t -test to compare the achievement of study between groups. The t -test result showed that the academic achievement in learning with group 1 was statistically significant than the learner in group 2. The effectiveness of the blended e-learning has been proved as the logistic regression analysis showed that the rate of the attendance in the cyber lecture functioned as indicator that enable to predict the acceptance.

• The Journal of the Korean dental association
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• v.55 no.7
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• pp.440-448
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• 2017

Objectives : Currently, it is being reported that new health technology (HT) is introduced and spread throughout Korea at a very fast rate. However, the current status of new HT related to dentistry has not been known or studied. Therefore, this study aims to understand the present state and awareness on dentistry-related domestic new HT via surveys and research, and thus apply this as a reference to construct an effective new HT-related system in the field of dentistry. Methods : The assessment status of New Health Technology Assessment (nHTA) committee was searched on the website for any updates on new HT5). The cases were searched in the range between Jan 1 2012 and Jul 31 2016 by submission date and were analyzed by year, division of technology, progress and major operating practitioner. Among those, technologies utilized by dentists were additionally analyzed. The survey result was obtained by combining responses of 25 participants from the workshop for new HT application and 11 members of Korean Association of Oral and Maxillofacial Surgeons (KAOMS). The workshop was co-hosted by KAOMS and Clinical Translational Research Center for Dental Science (CTRC) under Seoul National University Dental Hospital (SNUDH). Results : Most of the respondents to the survey have heard of new health technology but were unaware of the application procedure. 'Safety and effectiveness' was selected the most for things to consider when introducing new HT, followed by 'scientific evidence of the technology.' For new dental HT status, submissions between 2012 and Jul 31 2016 were analyzed by major operating practitioner, including cases where there are multiple practitioners. Yet, only 19 cases (17 %) of dentists were reported. Among 385 cases approved by nHTA, only 2 cases included dentists. Conclusions : Active publicity by the government on new HT and its application procedure, and continued interest and research in the dental and medical community is likely to be required for the development of dentistry.