• Industrial Engineering and Management Systems
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• v.9 no.2
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• pp.121-130
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• 2010

In today's uncertain economic environment, economic risk is inherent in making large investments on manufacturing facilities. It is, therefore, practically meaningful to divide investment over multiple periods, reducing the risk of investment. Then, the cash-flow over the entire planning horizon would comprise positive inflow and negative outflow. In this case, in general, evaluation by internal rate of return (IRR) is not feasible, because multiple IRRs are involved. This paper deals with a problem of evaluating profitability, as well as risk, of investment alternatives made in multiple times of investment over the entire horizon. Typically, an additional investment is required after the initial one, for expanding manufacturing capacity or other reasons. The paper pays attention to a unit cash-flow over two periods, decomposing the total cash-flow into a series of unit cash-flow patterns. It is easy to evaluate profitability of a unit cash-flow by using IRR. The total cash-flow can be decomposed into the series of two types of unit cash-flows: an investment type one (negative-positive) and the borrowing type one (positive-negative). This paper, therefore, proposes a method in which only the borrowing type unit cash-flow is eliminated in the series by converting total cash-flow using capital interest rate. Then, a unique IRR can be obtained and the profitability is evaluated. Thus, the paper extends the method of IRR so that it may help decision making in complicated cash-flow pattern observed in practice.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.1
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• pp.1-8
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• 2021

As a nation experiencing rapid economic growth, South Korea and its government have made a continuous effort toward efficient research investments to achieve transformation of the Korean industry for the fourth industrial revolution. To achieve the maximum effectiveness of the research investments, it is necessary to evaluate its funding's worth and default risk. Thus, incorporating the concepts of the Black-Scholes-Merton model and the Greeks, this study develops a default-risk evaluation model in the foundation of a system dynamics methodology. By utilizing the proposed model, this study estimates the monetary worth and the default risks of research funding in the public and private sectors of Information and Communication technologies, along with the sensitivity of the R&D economic worth of research funding to changes in a given parameter. This study finds that the public sector has more potential than the private sector in terms of monetary worth and that the default risks of three types of research funding are relatively high. Through a sensitivity analysis, the results indicate that uncertainty in volatility, operation period, and a risk-free interest rate has trivial impacts on the monetary worth of research funding, while volatility has large impacts on the default risk among the uncertain factors.

• The Journal of the Korea Contents Association
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• v.9 no.9
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• pp.259-267
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• 2009

This study intends to figure out the variables affecting the degree of female undergraduates' perceived risk of smoking and utilize them as foundational data for educating them to quit smoking. Thereupon, it conducted a self-administered survey from May 18 till 25 of 2009 to 231 female undergraduates attending S University located in Gyeonggi-do. The study tool contains 19 items of general characteristics and 8 of the degree of perceived risk of smoking. The data collected were analyzed by SPSS program, and the following results were gained. 1. According to the result on the degree of female undergraduates' perceived risk of smoking, the degree was shown high as the average was 4.32 among the perfect score of 5; thus, the degree of perceived risk of smoking was high. 2. In terms of the household economic level, female undergraduates with the lower economic level indicated the higher degree of perceived risk of smoking. There existed significant difference by their economic level (F=7.14, p<.01). 3. In regard of whether the female undergraduate smokes or not, the non-smoker perceives the degree of risk of smoking more highly than the smoker does; there is significant difference by whether they smoke or not (t=-2.43, p<.05). 4. About the number of friends who smoke, female undergraduates with one smoking friend show the highest degree of perceived risk of smoking. Those haying three or more smoking friends indicate the low degree of perceived risk of smoking. There exists significant difference by the number of smoking friends they have (F=3.14, p<.05). 5. According to the degree of perceived risk of smoking by their school life satisfaction, the female undergraduates expressing 'dissatisfaction' show the highest degree of perceived risk of smoking while 'satisfaction' indicates the average level. This was statistically significant difference (F=4.81, p<.01). Therefore, it is thought that it will be necessary to develop programs based on this research which can allow female undergraduates to team the importance of quitting smoking and actively participate in the education for it.

• Journal of Korea Water Resources Association
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• v.55 no.6
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• pp.421-435
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• 2022

As natural disasters have been increasing due to climate change, sustainable solutions are in need to alleviate the degree of drought hazard, assess and project the drought influence based on future climate change scenarios. In assessing drought risk, socio-economic factors of the region must be considered along with meteorological factors. This study categorized drought hazard, exposure, and vulnerability as three major components of drought risk according to the Intergovernmental panel on Climate Change (IPCC) risk assessment framework, and selected indices for each component to quantify the drought risk in South Korea according to the mid-size basins. Combinations of climate scenarios (Representative Concentration Pathway; RCP 2.6 and RCP 8.5) and socio-economic scenarios (Shared Socio-economic Pathways; SSP 1, SSP2 and SSP3) for the near future (2030-2050) ant the far future (2080-2099) were utilized in drought risk analysis, and results were compared with the historical data (1986-2005). In general, the drought risks for all scenarios shows large increases as time proceeds to the far furture. In addition, we analyzed the rank of drought hazard, exposure, vulnerability for drought risk, and each of their contribution. The results showed that the drought hazard is the most contributing component to the increase of drought risk in future and each basin shows varying contributing components. Finally, we suggested countermeasures for each basin according to future climate change scenarios, and thus this study provides made the basis for establishing drought management measures.

• Journal of the Korea Safety Management & Science
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• v.23 no.1
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• pp.57-64
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• 2021

Recently, advanced countries assessment the risk of fire to prevent large-scale damage to high-rise buildings, In addition, performance-Based design, which is a fire risk assessment, is being conducted in Korea to prevent massive damage to high-rise buildings. However, unlike advanced countries, fire risk assessment in Korea is subject to fire risk assessment only for objects subject to consent from fire-fighting facilities such as building permits, When building engineers and fire-fighting engineers assessment the risk of fire, It has always been discussed because the results vary depending on which part of the evaluation is focused between economic feasibility and safety. Therefore, in this study, we would like to propose a fire risk assessment process suitable for domestic conditions by comparing the process of performance-based design, which is a domestic fire risk assessment, and the process of Iso/TC 16732 which is an overseas fire risk assessment.

• Journal of the Chungcheong Mathematical Society
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• v.26 no.2
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• pp.343-349
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• 2013

The optimal portfolio selection problem under inflation risk is considered in this paper. There are three assets the economic agent can invest, which are a risk free bond, an index bond and a risky asset. By applying the martingale method, the optimal consumption rate and the optimal portfolios for each asset are obtained explicitly.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.9
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• pp.4091-4094
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• 2014

Background: This study used the receiver operating characteristic curve (ROC) to analyze Surveillance, Epidemiology and End Results (SEER) bronchioaveolar carcinoma data to identify predictive models and potential disparity in outcomes. Materials and Methods: Socio-economic, staging and treatment factors were assessed. For the risk modeling, each factor was fitted by a Generalized Linear Model to predict cause specific survival. The area under the ROC was computed. Similar strata were combined to construct the most parsimonious models. A random sampling algorithm was used to estimate modeling errors. Risk of cause specific death was computed for the predictors for comparison. Results: There were 7,309 patients included in this study. The mean follow up time (S.D.) was 24.2 (20) months. Female patients outnumbered male ones 3:2. The mean (S.D.) age was 70.1 (10.6) years. Stage was the most predictive factor of outcome (ROC area of 0.76). After optimization, several strata were fused, with a comparable ROC area of 0.75. There was a 4% additional risk of death associated with lower county family income, African American race, rural residency and lower than 25% county college graduate. Radiotherapy had not been used in 2/3 of patients with stage III disease. Conclusions: There are socio-economic disparities in cause specific survival. Under-use of radiotherapy may have contributed to poor outcome. Improving education, access and rates of radiotherapy use may improve outcome.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.454-459
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• 2003

Feasibility study on large scale projects like an investment on infrastructure development is very important because it provides fundamental data which determine the total investment size and duration. However, previous feasibility studies have a few problems of ambiguous estimation standards, unsystematical estimation methods, and so on. Accordingly, this study intends to regulate tile problems on economic feasibility as well as financial feasibility study which have been considered more critical in recent time, subsequently presents a reform measure. Also, this study identifies predictable risks during the feasibility study, presents a scheme which lets investor and owner control the risk themselves through a process which uses theoretical and political management plans.

• Journal of Korean Academy of Nursing
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• v.52 no.5
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• pp.499-510
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• 2022

Purpose: This study investigated the association between adolescent health behaviors (drinking, smoking, and drug use) and sexual intercourse, as well as the moderating effects of economic status, cohabitation with parents, and school type, among adolescents in Korea. Methods: Secondary data from the 16th Adolescent Health Behavior Survey (2020) were used. A total of 395 schools and 54,948 middle and high school students participated in the study. Complex sample frequency analysis, the Rao-Scott test, and complex sample logistic regression analyses were performed. Results: Sexual intercourse rates for men and women were 5.8% and 3.3%, respectively. Approximately 7.3% of high school students and 1.8% of middle school students reported having had sexual relations. Drinking (odds ratio [OR] = 3.15, 95% confidence interval [CI] = 2.82~3.52), smoking (OR = 6.75, 95% CI = 5.90~7.71), and drug use (OR = 3.03, 95% CI = 2.23~4.11) significantly increased the risk of sexual intercourse. Economic status and school type had moderating effects on the association between drinking and sexual intercourse. Conclusion: Adolescent drinking, smoking, and drug use are associated with a higher risk of sexual experience. Thus, to reduce this risk, controlling alcohol consumption, smoking, and drug use is necessary. In addition, programs for healthy lifestyles and sexual intercourse should be differentiated according to the school type and the economic conditions of the adolescents' households.

• Earthquakes and Structures
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• v.22 no.2
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• pp.109-120
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• 2022

Older or damaged structures can require significant retrofit to ensure they perform well in subsequent earthquakes. Supplemental damping devices are used to achieve this goal, but increase base shear forces, foundation demand, and cost. Displacement reduction without increasing base shear is possible using novel semi-active and recently-created passive devices, which offer energy dissipation in selected quadrants of the force-displacement response. Combining these devices with large, strictly passive energy dissipation devices can offer greater, yet customized response reductions. Supplemental damping to reduce response without increasing base shear enables a net-zero base shear approach. This study evaluates this concept using two incremental dynamic analyses (IDAs) to show displacement reductions up to 40% without increasing base shear, more than would be achieved for either device alone, significantly reducing the risk of response exceeding the unaltered structural case. IDA results lead to direct calculation of reductions in risk and annualized economic cost for adding these devices using this net-zero concept, thus quantifying the trade-off. The overall device assessment and risk analysis method presented provides a generalizable proof-of-concept approach, and provides a framework for assessing the impact and economic cost-benefit of using modern supplemental energy dissipation devices.