• Journal of the Korean Society of Safety
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• v.31 no.5
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• pp.141-148
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• 2016

There exists required safety integrity level (SIL) to assure safety in accordance with international standards for every electrical / electronics / control equipment or systems with safety related functions. The SIL is allocated from lowest level (level 0) to highest level (level 4). In order to guarantee certain safety level that is internationally acceptable, application of methodology for SIL allocation and demonstration based on related international standards is required. Especially, in case of the SIL allocation method without determining of quantitative tolerable risk, the additional review is needed to check whether it is suitable or not is required. In this study, the quantitative risk reduction model based on the safety integrity allocation results of railway platform screen door system using Risk Graph method has been examined in order to review the suitability of quantitative risk reduction according to allocated safety integrity level.

• Journal of the Korean Society of Safety
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• v.31 no.4
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• pp.156-163
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• 2016

There exists required safety integrity level (SIL) to assure safety in accordance with international standards for every electrical / electronics / control equipment or systems with safety related functions. The SIL is allocated from lowest level (level 0) to highest level (level 4). In order to guarantee certain safety level that is internationally acceptable, application of methodology for SIL allocation and demonstration based on related international standards is required. However, the theoretical and practical study for safety integrity level is barely under way in the domestic railway industry. This research studied not only the global process of SIL allocation to guarantee safety in accordance with international standards for safety related equipment and system, but the quantitative methodology based on international standard and the semi-quantitative methodology as alternative way for SIL allocation. Specifically, the systematic SIL allocation for platform screen door system of railway is studied applying the semi-quantitative methodology in order to save much time and effort compared to quantitative method.

• Journal of Korean Society of Transportation
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• v.25 no.1 s.94
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• pp.49-59
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• 2007

This study has examined the allocation of risk in Korea's private provided Infrastructure(PPI) with the following contents (1) Developing a quantitative risk allocation model for Korea's PPI and (2) examining the implication of changes in the minimum revenue guarantees (MRG) clause of government legislation using the developed empirical model. The model of this study adopts and extends H. Yamaguchi's model developed in 2002. To investigate Korea's actual risk allocation deals, the author incorporated the MRG framework. The payment related to the MRG is indeterminable. Hence. the average MRG rate was calculated using probabilistic risk analysis. The risk allocation model is applied to the two eases to validate the model and evaluate the project's VFM(Value for Money). As the revenue guarantee rate is lowered, the government subsidies are increased. This in turn worsens VFM. The same relationship is true when the revenue guarantee Period is shortened.

• Communications for Statistical Applications and Methods
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• v.25 no.6
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• pp.605-618
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• 2018

Risk management has been a crucial part of the daily operations of the financial industry over the past two decades. Value at Risk (VaR), a quantitative measure introduced by JP Morgan in 1995, is the most popular and simplest quantitative measure of risk. VaR has been widely applied to the risk evaluation over all types of financial activities, including portfolio management and asset allocation. This paper uses the implementations of multivariate GARCH models and copula methods to illustrate the performance of a one-day-ahead VaR prediction modeling process for high-dimensional portfolios. Many factors, such as the interaction among included assets, are included in the modeling process. Additionally, empirical data analyses and backtesting results are demonstrated through a rolling analysis, which help capture the instability of parameter estimates. We find that our way of modeling is relatively robust and flexible.

• Journal of the Korean Operations Research and Management Science Society
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• v.20 no.1
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• pp.85-99
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• 1995

Increasingly, risk analysis is becoming important ingredients in achieving the successful implementation and application in the area of the project management. The project management system is designed to manage or control the project resources on a given activity within time, cost and performance so called TPPM (Total Productive Project Management). In this research, a risk analysis model misproposed to identify potential problem areas, quantify the risks, and generated the chice of the action that can be taken to reduce the risk. In addition two analysis models are proposed : 1) risk factor model and 2) network simulation model using VERT (Venture Evaluation and Review Technique ). The objective of the remodels is to estimate the schedule, cost performance risks. These proposed quantitative models for project risk analysis are proving its value for the project managers who need to assess the risk of changes in cost, schedule, or performance. The proposed models will be used in the area of project selection, evaluation and the allocation of project resources.

• Journal of Construction Engineering and Project Management
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• v.7 no.3
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• pp.15-25
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• 2017

The existence of material price volatility in construction projects puts forward substantial risks for all parties involved. Depending on the parties involved in the project, type of contracts, and state of the market various risk management strategies are practiced by contracting parties to manage project risks related to price volatility. Unfortunately, in many cases companies fail to select an adequate approach to better manage volatilities of material prices due to the lack of a decision support system to aid in the selection of an appropriate strategy based on the project characteristics. The aim of this study is to identify critical project factors and align them to documented strategies to manage price volatility based on an extensive literature review and industry interviews. This study found Integrated Project Delivery (IPD) as the ideal strategy with respect to project duration; quantitative risk management methods with respect to the cost; and Price Adjustment Clauses (PAC) with respect to the risk allocation, as the top price volatility management strategies.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.855-859
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• 2009

In this paper, we introduce the estimation method by Risk or SIL(Safety Integrity Level) for the criterion of safety assurance and summarize each application method and target. IEC 62278(EN 50126) which is international standard for the specification and verification of the railway system RAMS indicate a criterion of safety assurance. Especially, it recommend the safety verification by continuous verification as the order of requirement establishment, design, manufacture, installation, operation, and maintenance for the equipment not easy to quantify the operation environment. In this paper, we study the SIL requirement allocation method relating to internal new system development and existing system improvement by analysing SIL recommendations which were used to understand SIL for a train control equipment in 1990s in IRSE and theoretically their allocation background. This paper help the safety management of Korea train control system to develope the quantitative management procedure as international level by analyzing the SIL requirement allocation by operation agency and the right SIL verification procedure by manufacture and indicating the example to assure safety because it is necessary for improvement and localization for the Korea train control system having highly dependence on aboard technology.

• Korean Journal of Microbiology
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• v.37 no.2
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• pp.101-108
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• 2001

Risk assessment defines as the process of estimating both the probability that an event will occur and the probable magnitude of its adverse effects. Chemical or microbial risk assessment generally follows four basic steps, that is, hazard identification, exposure assessment, dose-response assessment, and risk characterization. Risk assessment provides an effective framework for determining the relative urgency of problems and the allocation of resources to reduce risks. Using the results of risk analyses, we can target prevention, reme-diation, or control effects towards areas, sources, or situations in which the greatest risk reductions can be achieved with resources available. Risk assessment is also used to explain chemical and microbial risks as well as ecosystem impacts. Moreover, this process, which allows the quantitation and comparison of diverse risks, lets risk managers utilize the maximum amount of complex information in the decision-making process. This information can also be used to weigh the cost and benefits of control options and to develop standards or treatment options.

• Journal of the Korean Society of Industry Convergence
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• v.27 no.2_2
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• pp.467-473
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• 2024

Metaheuristics' impact is profound across many fields, yet domestic financial portfolio optimization research falls short, particularly in asset allocation. This study delves into metaheuristics for portfolio optimization, examining theoretical and practical benefits. Findings indicate portfolios optimized via metaheuristics outperform the Dow Jones Index in Sharpe ratios, underscoring their potential to enhance risk-adjusted returns significantly. Tabu search, in comparison to Simulated Annealing, demonstrates superior performance by efficiently navigating the search space. Despite these advancements, practical application remains challenging due to the complexities in metaheuristic implementation. The study advocates for broader algorithmic exploration, including population-based metaheuristics, to refine asset allocation strategies further. This research marks a step towards optimizing portfolios from an extensive array of financial assets, aiming for maximum efficacy in investment outcomes.

• Korean Journal of Clinical Pharmacy
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• v.30 no.3
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• pp.169-176
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• 2020

Background: Most meta-analyses of risk factors for severe or critical outcomes in patients with COVID-19 only included studies conducted in China and this causes difficulties in generalization. Therefore, this study aimed to systematically evaluate the risk factors in patients with COVID-19 from various countries. Methods: PubMed, Embase, and Web of Science were searched for studies published on the mortality risk in patients with COVID-19 from January 1 to May 7, 2020. Pooled estimates were calculated as odds ratio (OR) with 95% confidence interval (CI) using the random-effects model. Results: We analyzed data from seven studies involving 26,542 patients in total in this systematic review and meta-analysis. Among the patients, 2,337 deaths were recorded (8.8%). Elderly patients and males showed significantly higher mortality rates than young patients and females; the OR values were 3.6 (95% CI 2.5-5.1) and 1.2 (95% CI 1.0-1.3), respectively. Among comorbidities, hypertension (OR 2.3, 95% CI 1.1-4.6), diabetes (OR 2.2, 95% CI 1.2-3.9), cardiovascular disease (OR 3.1, 95% CI 1.5-6.3), chronic obstructive pulmonary disease (OR 4.4, 95% CI 1.7-11.5), and chronic kidney disease (OR 4.2, 95% CI 2.0-8.6) were significantly associated with increased mortalities. Conclusion: This meta-analysis, involving a huge global sample, employed a systematic method for synthesizing quantitative results of studies on the risk factors for mortality in patients with COVID-19. It is helpful for clinicians to identify patients with poor prognosis and improve the allocation of health resources to patients who need them most.