• Journal of Industrial Technology
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• v.29 no.A
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• pp.101-110
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• 2009

Due to frequent occurrence of a localized torrential downpour caused by global warming and change of outflow tendency caused by rapid urbanization and industrialization, risk analysis must be carried out in levee design with uncertainty. In this study, reliability analysis was introduced to quantitatively evaluate the overtopping risk of levee by the uncertainty. First of all, breaking function was established as a function of flood stage and height of levee. All variables of breaking function were considered as random variables following any distribution functions, and the risk was defined as the possibility that the flood stage is formed higher than height of levee. The risk evaluation model was developed with AFDA (Approximate Full Distribution Approach). The flood stage computed by 2-D numerical model FESWMS-2DH was used as input data for the model of levee risk evaluation. Risk for levee submergence were quantitatively presented for levee of Wol-Song-Cheon.

• Journal of the Korean Society of Earth Science Education
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• v.16 no.1
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• pp.103-132
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• 2023

This study developed a risk society education program for undergraduate students to help them understand the epistemological uncertainty of risk caused by COVID-19. And it was applied to science-related classes of undergraduate students, and the purpose was to examine the degree of understanding and thoughts of undergraduate students about the risk society through science writing. As a result, it was found that the degree of understanding of the risk society was very high in all participating students regardless of their majors in science, engineering, humanities and social sciences. In addition, it was analyzed that the risk society education program helped undergraduate students to resolve the epistemological uncertainty of the risk of COVID-19 and to have an attitude to overcome the the difficult mind due to the COVID-19 distancing. The results of this study suggest that risk society education is necessary for future generations living in an era of risk of climate change and pandemic that exceeds the prediction range of science and technology in science education.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.238-244
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• 2022

Civil projects are associated with many uncertainties because they involve a long duration, many resources, a large area, and many supply chains. Therefore, the price of a civil project is not simply proportional to the quantity and unit price of the item but has a variable value, including uncertainty risk. This study investigates the influence of the uncertainty factors in the pre-bid clarification document on bid price formation during the project bidding phase. To this end, civil projects from the California Department of Transportation (Caltrans) were used as research data. This study randomly selected fifty sample data from each of twelve counties from 2008-to 2020: six hundred. The authors observed that each project sample had 0 to n query cases due to uncertainty. Then, this study examined the project uncertainty cases and categorized them into the following four uncertainty factors: 'conflict' (UF1), 'impossibility' (UF2), 'lack' (UF3), and 'missing' (UF4). Under the extracting process, the cases are classified into four uncertainty factors. With the project not containing any uncertainty factors as a control group, the project containing these uncertainty factors was designated as an experimental group. After comparing the bidder's price, the experimental group's bid price was higher than the control group's. This result suggests that uncertainty factors in bid documents induce bidders to set a high bid price as a defense against uncertainty.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.38 no.1
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• pp.83-89
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• 2015

Selection of efficient supplier is a very important process as risk or uncertainty of a supply chain and its environment are increasing. Previous deterministic DEA and probabilistic DEAs are very limited to handle various types of risk and uncertainty. In this paper, I propose an improved probabilistic DEA which consists of two steps; Monte Carlo simulation and statistical decision making. The simulation results show that the proposed method is proper to distinguish supplier's performance and provide statistical decision background.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.3
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• pp.302-310
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• 2018

Despite the accident rate for fishing vessels accounts for 70% of all maritime accidents, few studies on such accidents have been done and most of the them mainly focus on causes and mitigation policies to reduce that accident rate. Thus, this risk analysis on sea accidents is the first to be performed for the successful and efficient implementation of accident reducing measures. In risk analysis, risk is calculated based on the combination of frequency and the consequence of an accident, and is usually expressed as a single number. However, there exists uncertainty in the risk calculation process if one uses a limited number of data for analysis. Therefore, in the study we propose a probabilistic simulation method to forecast risk not as a single number, but in a range of possible risk values. For the capability of the proposed method, using the criteria with the ALARP region, we show the possible risk values spanning across the different risk regions, whereas the single risk value calculated from the existing method lies in one of the risk regions. Therefore, a decision maker could employ appropriate risk mitigation options to handle the risks lying in different regions. For this study, we used fishing vessel accident data from 1988 to 2016.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.467-467
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• 2012

As the features of recent flood are spatially concentrated, loss of life and property increase by the impact of climate change. In addition to this the public interest in water control information is increased and socially reasonable justification of water control policy is needed. It is necessary to estimate the flood risk in order to let people know the status of flood control and establish flood control policy. For accurate flood risk analysis, we should consider inter-relation between causal factors of flood damage. Hence, flood risk analysis should be applied to interdependence of the factors selected. The Bayesian networks are ideally suited to assist decision-making in situations where there is uncertainty in the data and where the variables are highly interlinked. In this research, to provide more proper water control information the flood risk analysis is performed using the Bayesian networks to handle uncertainty and dependency among 13 specific proxy variables.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.16 no.6
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• pp.119-130
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• 2021

This study is a study on the regulatory focus and entrepreneurship that affect entrepreneurial motivation under uncertainty. In the empirical analysis results between the prevention focus, risk taking, and economic entrepreneurial motive, which were not observed in previous studies in Korea, this study tried to supplementally verify the previous studies by focusing on the limitations of the sample suggested as limitations. In particular, under a special external environment where uncertainty is deepening due to COVID-19 and the economic situation is being severely hit, we regressively analyze regulatory focus and risk taking, which are innate personal characteristics that can affect entrepreneurial motives. The mediating effect of risk taking was demonstrated. As a result of the empirical results, it was found that the prevention focus, risk taking, and economic entrepreneurial motivation had a significant effect, and it was shown that risk taking had a mediating effect between the prevention focus and the economic entrepreneurial motivation. This result is meaningful as a result not observed in previous studies, and it is judged that the control focus, which is an individual characteristic with a large innate tendency, interacts with the risk taking of the acquired tendency to influence the motivation to start a business. The results of this study can be of practical help by understanding and concentrating on regulatory focus and risk taking when conducting entrepreneurship or entrepreneurship education programs to entrepreneurs who dream of or want to start a business amid the growing uncertainty of the external environment. On the other hand, it is necessary to confirm whether these results, which are different from previous studies, are the effect of sample diversity or the external environment such as Corona 19, and re-verification through additional research is needed in the future.

• Earthquakes and Structures
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• v.6 no.1
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• pp.19-43
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• 2014

A risk assessment framework for evaluating building structures is implemented in this study. This framework allows considering sources of uncertainty both on structural capacity and seismic demand. In particular randomness on seismic load, incident angle, material properties, floor mass and structural damping are considered; in addition the choice of fibre modelling versus plastic hinge model is also considered as a source of uncertainty. The main objective of this work is to study the contribution of these sources of uncertainty on the fragilities of steel and steel-reinforced concrete composite 3D building structures. The fragility curves are expressed in the form of a two-parameter lognormal distribution where vertical statistics in conjunction with metaheuristic optimization are implemented for calculating the two parameters.

• Journal of Environmental Science International
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• v.20 no.3
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• pp.329-340
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• 2011

The probability concepts mainly used for rainfall or flood frequency analysis in water resources planning are the frequentist viewpoint that defines the probability as the limit of relative frequency, and the unknown parameters in probability model are considered as fixed constant numbers. Thus the probability is objective and the parameters have fixed values so that it is very difficult to specify probabilistically the uncertianty of these parameters. This study constructs the uncertainty evaluation model using Bayesian MCMC and Metropolis -Hastings algorithm for the uncertainty quantification of parameters of probability distribution in rainfall frequency analysis, and then from the application of Bayesian MCMC and Metropolis- Hastings algorithm, the statistical properties and uncertainty intervals of parameters of probability distribution can be quantified in the estimation of probability rainfall so that the basis for the framework configuration can be provided that can specify the uncertainty and risk in flood risk assessment and decision-making process.

• Asia pacific journal of information systems
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• v.12 no.4
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• pp.101-120
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• 2002

Risk management or risk-based approach of software project management was developed to explain the effects of requirement uncertainty, control standardization, interactions on software quality. Based on a prior theory, five hypotheses were derived and empirically tested using a survey design. Data from 117 members in 3 SI companies support for the path model, and three of five hypotheses. The results showed that decreases in requirement uncertainty and increases in control standardization were directly associated with increases in the interactions between user and project teams, which, in turn, led to increases software quality. The findings suggested that the direct effect on software quality is primarily due to the interactions between user and project teams, rather than requirement uncertainty and control standardization.