• 한국경영과학회지
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• 제5권1호
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• pp.61-72
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• 1980

This paper is an attempt at developing a method for the analysis and estimation of the effects of project disruptions due to uncertainties. Such uncertainties may result from design changes in large-scale, complex, research and development, or construction projects. An entropical risk analysis method is developed. The method is able to estimate the project capacity to handle equivocation due to design changes and the effects of project disruptions. In an attempt to evaluate the predictive capability of the method, it is compared with the results obtained by a computer Monte Carlo simulation program. It is shown that the entropical risk analysis method may be suggested as an expedient means of evaluating project status for management in the different stages of project execution.

• 한국통계학회:학술대회논문집
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• 한국통계학회 2003년도 추계 학술발표회 논문집
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• pp.319-324
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• 2003

본 논문에서는 matched-pair design에서의 두 처리간 동등성/ 비열등성 검정에 대해 고려하였다. 기존에 비율차이나 risk ratio관점에서 동등성/비열등성 검정을 시행한 것과는 달리, 본 논문에서는 odds ratio에 기초하여 두 가지 검정통계량을 유도하였다. (1) constrained maximum likelihood estimator(mle)를 이용한 fieller type 통계량 (2) 제약없이 구한 mle를 사용한 wald-type 통계량). 비율 차이나 risk ratio에 기초한 기존의 통계적 방법들(비율차이에 근거한 (3) score-type 통계량과 (4) wald-type 통계량, risk ratio에 기초한 (5) fieller-type 통계량과 (6) wald-type 통계량)과 본 논문에서 제시한 두가지 통계량의 성능을 비교하기 위해 모의실험을 시행하였다. 모의실험 결과, 본 논문에서 제안한 constrained mle를 사용한 fieller type 통계량은 empirical type I error 측면에서 매우 만족스러운 결과를 보이고 있으며, 특히 비대각 셀의 확률이 작아질 경우에도 안정적인 성능을 보여준다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.1871-1876
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• 2007

To establish the national railway safety system, the railway total safety technology development project has been promoted by Ministry of Construction and Transportation (MOCT) since August 2004. The project has producted successful results in many areas of railway safety, however, it is required that the research field should be re-examined to meet the aim of the project. To do that, the precedence of the investment of research resources should be reviewed and determined. The risk of serious railway accidents such as train collision, derailment and level crossing accidents are estimated. From the estimation result and the statistics on the railway accidents over fast few years, the risk factors of railway accidents can be calculated.

• 한국안전학회지
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• 제12권4호
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• pp.143-152
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• 1997

Probabilistic Safety Assessment(PSA) is an engineering analysis of the possible contributors to the risk from a nuclear power plant. It consist of three phases named as Level 1, 2 and 3. Level 1 PSA mainly focused in this paper is the phase of system analysis which includes the development of accident scenarios and the frequency estimation of each scenario. It covers also the system reliability analysis, component data analysis, and human reliability analysis. PSA have become a standard tool in safety evaluation of nuclear power plants. The main benefit of PSA is to provide insights into plant design, performance and environmental impacts, including the identification of dominant risk contributors and the comparison of options for reducing risk.

• 정보화연구
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• 제9권4호
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• pp.365-376
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• 2012

We examine the value of information sharing in the context of supplier-buyer relationships after controlling for trading partners' opportunism. Given that trading partners' opportunism is not randomly chosen, we explicitly incorporate their self-selection process into our estimation procedure by employing Heckman's self-selection model. According to our analysis, firms that have built safeguards via mutual trust, commitments and information sharing experience less opportunistic risk in supplier-buyer relationships. Our findings also suggest that information sharing has a positive impact on firm performance after controlling for opportunism. Further, firms that are less exposed to trading partners' opportunistic risk have achieved a higher performance than others that are more exposed. Importantly, higher performance for those firms with less opportunistic risk is driven by safeguards in supplier-buyer relationships as well as information sharing. Our findings can be applied for systems analysts to design information systems of supplier-buyer transactions.

• 한국안전학회지
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• 제8권2호
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• pp.58-63
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• 1993

Recently, a large amount of flammable or explosive materials have been handled or stored in chemical industries. H the equipments fail or the materials release in consequence of operation errors, fire and explosion could occur to them. Thus, risk assessment using quantification of risks is very important when design of processes and modifications of installed processes are performed. The purpose of this study is to develop the program for fire and explosion index in order to quantify the expected damage of fire and explosion incidents in chemical plants, to identify equipment that would be likely to contribute to the creation or escalation of an incident, to comunicate the potential fire and explosion risk to management and to account of damage cost.

• Earthquakes and Structures
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• 제13권4호
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• pp.365-375
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• 2017

Seismic risk management has two main technical aspects: to recommend the construction of high-performance buildings and other structures using earthquake-resistant designs or evaluate existing ones, and to prepare emergency plans using realistic seismic scenarios. An overview of seismic risk assessment methodologies in Croatia is provided with details regarding the components of the assessment procedures: hazard, vulnerability and exposure. For Croatia, hazard is presented with two maps and it is expressed in terms of the peak horizontal ground acceleration during an earthquake, with the return period of 95 or 475 years. A standard building typology catalogue for Croatia has not been prepared yet, but a database for the fourth largest city in Croatia is currently in its initial stage. Two methods for earthquake vulnerability assessment are applied and compared. The first is a relatively simple and fast analysis of potential seismic vulnerability proposed by Croatian researchers using damage index (DI) as a numerical value indicating the level of structural damage, while the second is the Macroseismic method.

• 한국항공운항학회지
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• 제29권2호
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• pp.1-13
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• 2021

Fuel costs represent one of the most substantial expenses for airlines, accounting for 20% - 36% of the airline's total operating cost. The present study discusses the so-called discretionary fuel that is additionally loaded at the discretion of airlines to cover unforeseen variations from the planned flight operations. The proper range of the discretionary fuel to be loaded for economic flight operations was estimated by applying Monte Carlo simulation technique. With this simulation model for loading discretionary fuel, airlines cannot only reduce the total amount of fuel to be consumed but also minimize the risk of unplanned flight disruptions caused by insufficient fuel on board. Airlines should be able to guarantee proper risk management processes for fuel boarding by carrying enough fuel to high-risk airports. This study would provide a practical guideline for loading proper amounts of discretionary fuel. Future researchers should be encouraged to improve this study by elaborating the weather variable.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.642-648
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• 2009

Determining the total duration for a construction project is an integral part of project management in the construction industry. This is to ensure the project and all its associated activities can be carried out and completed within the time frame stipulated. There are several commonly used scheduling methods and techniques in project management, some of which involves manual calculation while others involve computer software. This paper looks into the various time determination methods, extracting out their differences and similarities. It also seeks to draw out the problems when determining time for projects, especially those encountered of case studies. Based on the results from the case studies, there were delays on certain projects even though time determination had been carried out rigorously prior to the commencement of the projects. This paper seeks to develop a time determination model, which incorporates risk management techniques into the calculations in order to improve the method for time estimation to minimize the chances of project delay.

• 국제학술발표논문집
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• The 4th International Conference on Construction Engineering and Project Management Organized by the University of New South Wales
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• pp.162-167
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• 2011

Construction projects are full of risks. This is particularly the case in civil construction projects that are often featured with large scale, complexity and involving a large number of participating parties. The eventuation of risks typically results in extended project durations leading to an increase in the total project budget. The consequence can be amplified considering the significant impacts of civil construction projects on the society, from economical, environmental and social perspectives. This research investigates the significance of risks within civil construction projects and approaches to deal with risks. Semi-structured interviews were undertaken with local industry practitioners in South Australia on this matter. It is found that the industry is fairly aware of risks associated with civil construction projects and subsequently has procedures in place to attempt to minimize the impacts of these risks on the project outcomes. The interview results also indicate that there is limited utilization of software for the risk management purpose from the cost estimation perspective.