• Clinical Endoscopy
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• 제55권4호
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• pp.540-548
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• 2022

Background/Aims: Colorectal polyps are removed to prevent progression to colorectal cancer. Polyp size is an important factor for risk stratification of malignant transformation. Endoscopic size estimation correlates poorly with pathological reports and several factors have been suggested to influence size estimation. We aimed to gain insight into the factors influencing endoscopic polyp size estimation. Methods: Images of polyps in an artificial model were obtained at 1, 3, and 5 cm from the colonoscope's tip. Participants were asked to estimate the diameter and volume of each polyp. Results: Fifteen endoscopists from three large-volume centers participated in this study. With an intraclass correlation coefficient of 0.66 (95% confidence interval [CI], 0.62-0.71) for diameter and 0.56 (95% CI, 0.50-0.62) for volume. Polyp size estimated at 3 cm from the colonoscope's tip yielded the best results. A lower distance between the tip and the polyp was associated with a larger estimated polyp size. Conclusions: Correct endoscopic estimation of polyp size remains challenging. This finding can affect size estimation skills and future training programs for endoscopists.

• Journal of Electrical Engineering and Technology
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• 제9권6호
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• pp.1789-1794
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• 2014

This paper suggests an application method for a superconducting fault current limiter (SFCL) using an evaluation index to estimate the risk regarding the short-circuit capacity of the circuit breaker (CB). Recently, power distribution systems have become more complex to ensure that supply continuously keeps pace with the growth of demand. However, the mesh or loop network power systems suffer from a problem in which the fault current exceeds the short-circuit capacity of the CBs when a fault occurs. Most case studies on the application of the SFCL have focused on its development and performance in limiting fault current. In this study, an analysis of the application method of an SFCL considering the risk of the CB's short-circuit capacitor was carried out in situations when a fault occurs in a loop network power system, where each line connected with the fault point carries a different current that is above or below the short-circuit capacitor of the CB. A loop network power system using PSCAD/EMTDC was modeled to investigate the risk ratio of the CB and the effect of the SFCL on the reduction of fault current through various case studies. Through the risk evaluations of the simulation results, the estimation of the risk ratio is adequate to apply the SFCL and demonstrate the fault current limiting effect.

• The Journal of Asian Finance, Economics and Business
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• 제7권2호
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• pp.107-117
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• 2020

The research objective of the paper is to clarify the factors influencing system risks of listed companies in Vietnam, with a focus on clarifying the relationship and quantifying the impacts of ownership structure on systemic risk of listed companies. The data used in this study included financial statements and stock price data of listed companies on the Ho Chi Minh City Stock Exchange and Hanoi Stock Exchange of Vietnam stock market in the period from 2010 to 2017. The paper used the method of estimation in establising the regression models to choose among three models: Random Effect Model, Fixed Effect Model or Pooled OLS for regression using Stata statistical software. The research results showed that state ownership and ownership by foreign investors were positively related to systemic risk, while ownership by domestic investors had a reverse relationship with systemic risk of listed companies in Vietnam. In addition, as a control variable, both company size and profitability had an effect on the systemic risk of listed companies in the research sample. Based on the research results, the authors interpreted some of the implications in order to minimize systemic risks in the operation of listed companies in Vietnam.

• Nuclear Engineering and Technology
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• 제52권5호
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• pp.975-983
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• 2020

Since the Fukushima Daiichi accident in 2011, concerns for the safety of multi-unit Nuclear Power Plant (NPP) sites have risen. This is because more than 70% of NPP sites are multi-unit sites that have two or more NPP units and a multi-unit accident occurred for the first time. After this accident, Probability Safety Assessment (PSA) has been considered in many countries as one of the tools to quantitatively assess the safety for multi-unit NPP sites. One of the biggest concerns for a multi-unit accident such as Fukushima is that the consequences (health and economic) will be significantly higher than in the case of a single-unit accident. However, many studies on multi-unit PSA have focused on Level 1 & 2 PSA, and there are many challenges in terms of public acceptance due to various speculations without an engineering background. In this study, two kinds of multi-unit Level 3 PSA for multi-unit site have been carried out. The first case was the estimation of multi-unit risk with conservative assumptions to investigate the margin between multi-unit risk and QHO, and the other was to identify the effect of time delays in releases between NPP units on the same site. Through these two kinds of assessments, we aimed at investigating the level of multi-unit risk and understanding the characteristics of risk in a multiunit context.

• The Journal of Asian Finance, Economics and Business
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• 제10권1호
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• pp.57-66
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• 2023

There is a strong association between poverty levels and the probability of natural disasters. East Java, however, exhibits a distinct pattern. While the rate of poverty is declining, natural disasters are becoming more severe. Considering that East Java is an area with a high risk of natural disasters and a high poverty rate, this study aims to estimate the effect of environmental preservation and the magnitude of the impact of disasters as measured by the Disaster Risk Index (IRBI) on poverty. The 3SLS model is used on secondary data from 38 districts/cities from 2015 to 2021 as an analytical database. Based on the estimation results, there are 3 findings in this study: (i) the role of government, population development, and economic activity have a strong influence on nature conservation; (ii) nature conservation has a strong influence on disaster risk; and (iii) the disaster risk index has a strong effect on poverty. As a result, areas with a high level of disaster risk have a slower rate of poverty reduction. The role of this research is to show the need for the government's role in improving the quality of natural disaster mitigation anticipation, economic activity, and the role of the population in a sustainable manner.

• 한국빅데이터학회지
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• 제7권2호
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• pp.225-234
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• 2022

본 논문은 우리나라 국가 및 기업의 신용 리스크 네트워크를 추정하고 최근 거시경제 상황에 따른 국가-기업 및 기업-기업 간의 연결성 변화를 살펴본다. 2015년 11월부터 2022년 10월까지의 신용부도스왑(CDS) 스프레드 데이터를 이용하여 네트워크를 Graphical Lasso로 추정한 결과, 우리나라 국가 및 기업 신용리스크 간의 연결성이 유의미하게 존재한다. 특히, 수출입 및 외환 거래를 담당하는 은행 부문의 연결성이 전반적으로 높은 편이다. 통화정책 긴축 기조가 두드러진 2022년 들어서는 공통 익스포져가 확대되어 이러한 연결성이 커진 것으로 보인다.

• 한국항해항만학회지
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• 제43권3호
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• pp.166-171
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• 2019

항로표지사고는 항로표지의 신뢰성을 저하시키고, 관리자는 추가적인 업무가 부여되며, 이용자는 항해 중 부담감을 가지게 되는 등 모두에게 불편을 초래하는 사회적 비용(경제적 손실)이 발생하게 된다. 이러한 항로표지사고로 인한 경제적 손실을 추정하기 위해 선행연구에서는 항로표지사고의 사회적비용 추정모델을 생산손실비용, 행정비용, 위험비용의 합으로 제안하였으나, 위험비용의 추정에 대한 적절한 연구결과를 제시하지 못하였다. 따라서 본 연구에서는 선행연구에서 제시한 추정모델을 보완하여, 부산청 관할해역에서 최근 10년간(2008-2017년) 발생한 항로표지사고 249건에 대한 사회적비용을 산출하였다. 즉, 항로표지 사고의 위험비용은 항로표지가 비시장재화이므로 조건부가치측정법을 이용하여 산출하였다. 그 결과, 10년간 항로표지사고의 사회적비용은 생산손실비용 31억원(25.38%), 행정비용 17억원(13.62%), 위험비용 75억원(61.01%) 등 총 124억원으로 추정되었다.

• 한국재난정보학회 논문집
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• 제18권3호
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• pp.444-456
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• 2022

연구목적: 연구실험실에는 사전유해인자위험분석을 실시하도록 하고 있으나 실행하지 않는 연구실험실이 많다. 연구실험실의 안전을 확보하기 위한 목적으로 좀 더 쉽게 위험성평가를 적용 할 수 있도록 개선점을 찾고자 한다. 연구방법: 선행논문 및 과학기술정보통신부 연구실 안전관리 실태조사 보고서 자료를 활용하였다. 사전유해인자위험분석과 산업안전보건법에 의한 위험성평가를 비교하여 연구하였다. 연구결과: 연구실험실에 대한 위험성을 평가할 수 있는 기법을 제시하였다. 연구실험실 위험성평가시 가능성(빈도)과 중대성(강도)의 크기를 추정할 수 있도록 방법을 제시하였다. 결론: 연구실험실에서 쉽게 적용할 수 있도록 체크리스트 형태의 위험성평가 기법을 제시하였고, 실제 평가해 보았다. 연구실험실에서 위험성평가를 통한 개선을 실시하여 안전사고 예방에 도움이 될 것으로 기대한다.

• 아태비즈니스연구
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• 제11권3호
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• pp.243-260
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• 2020

Purpose - This paper aims to investigate the properties of crude oil based derivative security (DLS) focusing on step-down type for comprehensive understanding of its risk. Design/methodology/approach - Kernel estimation is conducted to figure out statistical feature of the process of oil price. We simulate oil price paths based on kernel estimation results and derive probabilities of hitting the barrier and early redemption. Findings - The amount of issuance for crude oil based DLS is relatively low when base prices are below $40 while it is high when base prices are around $60 or $100, which is not consistent with kernel estimation results showing that oil futures prices tend to revert toward $46.14 and the mean-reverting speed is faster as oil price is lower. The analysis based on simulated oil price paths reveals that probability of early redemption is below 50% for DLS with high base prices and the ratio of the probability of early redemption to the probability of hitting barrier is remarkably low compared to the case for DLS with low base prices, as the chance of early redemption is deferred. Research implications or Originality - Empirical results imply that the level of the base price is a crucial factor of the risk for DLS, thus introducing a time-varying knock-in barrier, which is similar to adjust the base price, merits consideration to enhance protection for DLS investors.

• 한국해양공학회지
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• 제26권1호
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• pp.60-63
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• 2012

The accident risks in the marine environment are increasing because of the tendency to build faster and larger ships. To secure ship safety, risk-based ship design (RBSD) was recently suggested based on a formal safety assessment (FSA). In the process of RBSD, a ship designer decides which risk reduction option is most cost-effective in the design stage using a cost-benefit analysis (CBA). There are three dimensions of risk in this CBA: fatality, environment, and asset. In this paper, we present an approach to estimate the environmental costs based on the size of an oil tanker involved in an accident using a neural network. An appropriate neural network model is suggested for the estimation,and the neural network is trained using IOPCF data. Finally,the learned neural network is compared with the cost regression equation by IMO MEPC 62/WP.13 (2011).