• Proceedings of the Computational Structural Engineering Institute Conference
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• 한국전산구조공학회 1999년도 봄 학술발표회 논문집
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• pp.3-10
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• 1999

This paper presents probabilistic risk assessment system model and methods for general construction projects and demonstrates the applicability of the approach to a specific subway construction project. The proposed system model entitled Integrated Risk Assessment System(IRAS) for construction projects is composed of four steps, which is newly reorganized and improved in order to be easily adjusted for a systematic PRA of construction projects. Based on the proposed model, and integrated prototype software is then developing for computer-aided PRA of construction projects under the environment of the graphic-user interface, which will be successfully applied to construction projects.

• Proceedings of the Korean Geotechical Society Conference
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.794-799
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• 2006

For various historical reasons and some technical reasons, the safety of dams has been controlled by an engineering standards-based approach, which has developed over many years, initially for the design of new dams, but increasingly applied over the past few decades to assess the safety of existing dams. And some countries were asked for risk assessment on existing dam, which included structural, hydraulic safety of dam and social risk. So, Many countries were developed and could be adapted as an additional tool to assist in decision-making for dam safety management.

• Korean Journal of Veterinary Research
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• 제47권2호
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• pp.259-263
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• 2007

The choice of input distribution in quantitative risk assessments modeling is of great importance to get unbiased overall estimates, although it is difficult to characterize them in situations where data available are too sparse or small. The present study is particularly concerned with accommodation of uncertainties commonly encountered in the practice of modeling. The authors applied parametric and non-parametric bootstrap simulation methods which consist of re-sampling with replacement, in together with the classical Student-t statistics based on the normal distribution. The implications of these methods were demonstrated through an empirical analysis of trade volume from the amount of chicken and pork meat imported to Korea during the period of 1998-2005. The results of bootstrap method were comparable to the classical techniques, indicating that bootstrap can be an alternative approach in a specific context of trade volume. We also illustrated on what extent the bias corrected and accelerated non-parametric bootstrap method produces different estimate of interest, as compared by non-parametric bootstrap method.

• Korean Journal of Veterinary Research
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• 제46권2호
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• pp.159-164
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• 2006

A stochastic simulation model incorporated with Reed-Frost approach was derived for evaluating diagnostic performance of a test used for a screening program of an infectious disease. The Reed-Frost model was used to characterize the within-herd spread of the disease using a hypothetical example. Specifically, simulation model was aimed to estimate the number infected animals in an infected herd, in which imperfect serologic tests are performed on samples taken from herds and to illustrate better interpreting survey results at herd-level when uncertainty inevitably exists. From a risk analysis point of view, model output could be appropriate in developing economic impact assessment models requiring probabilistic estimates of herd-level performance in susceptible populations. The authors emphasize the importance of knowing the herd-level diagnostic performance, especially in performing emergency surveys in which immediate control measures should be taken following the survey. In this context this model could be used in evaluating efficacy of a survey program and monitoring infection status in the area concerned.

• Advances in pediatric surgery
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• 제14권1호
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• pp.75-82
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• 2008

Neuroblastoma arises from the primitive neural crest cells, and is a common malignancy in childhood. The clinical features are characterized by biological heterogeneity. Neuronal degeneration and differentiation occur in some patients. However treatment in the high risk group accounting for approximately half, has not been satisfactory despite a multimodal approach. Therefore, effective treatment is determined by the risk group of prognostic factors, such as age at diagnosis, stage of disease, pathological finding and N-myc amplification. Neuroblastoma can be diagnosed prenatally, which suggests its origin during the normal embryogenesis. Recent knowledge of molecular biology, such as Trk genes, and the concept of cancer stem cells have given us some improved understanding on this disease. Currently, targeted therapies based on the molecular biology of neuroblastoma are under investigation and increasing survival rate and decreasing late complications could be appreciated.

• International conference on construction engineering and project management
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• The 2th International Conference on Construction Engineering and Project Management
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• pp.130-139
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• 2007

This paper presents a study on risk analysis in terms of contractor's costs in construction phase in which Crystal ball (software of Decisioneering, UK) has been utilized as a main tool. To realize it, a questionnaire survey has been carried out to identify the dominant factors that strongly influence contractor costs in Vietnam. Based on results of questionnaire investigation, the survey identified three factors which were duration of each construction task, costs of reinforcing steel, and cement. Then a spreadsheet model was created in order to analyze risks. The study also indicates that the cost of reinforcing steel and cement are the cause of risks for contractors. According to the suggested model, contractors may foresee the probability of completion within the approved budget, and the possibility of earning in accordance with owner's payment conditions.

• Korean Journal of Construction Engineering and Management
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• 제9권5호
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• pp.168-175
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• 2008

Project risk factors are major triggers in cost performance in construction projects. Both owners and contractors are highly concerned in managing their risks in earlier times. As such, it is needed to provide a robust risk evaluation methodology in identifying and assessing the potential risks before project execution. In previous research, risk identification was conducted only in specific phases, i. e., design, procurement, construction. Therefore, the comprehensive approach in risk management was limited and their quantifying method was not well-defined. Since the benefit of planning in earlier times are maximized compared to later times, the risk management should be implemented in earlier planning stage. This study provide a new risk evaluation method by incorporating previous research and extensive literature review. By quantifying each risk factor from an extensive industry survey, the proposed tool can enhance the reliability of each factor weight and also the weights are categorized from a various perspectives, i.e., owners, contractors, lager-scale company, smaller-scale company, building projects. The proposed tool can be also useful in deciding on whether to proceed a particular project and How much the project contingency would be set aside in project execution. The study findings can also expedite the risk management procedure in a more systematic approach.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• 제17권1호
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• pp.95-106
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• 2019

The decommissioning of nuclear power plants should be prepared by quantitative and qualitative risk assessment. Radiological and non-radiological hazards arising during decommissioning activities must be assessed to ensure the safety of decommissioning workers and the public. Decommissioning experiences by U.S. operators have mainly focused on deterministic risk assessment, which is standardized by the U.S. Nuclear Regulatory commission (NRC) and focuses only on the consequences of risk. However, the International Atomic Energy Agency (IAEA) has suggested an alternative to the deterministic approach, called the risk matrix technique. The risk matrix technique considers both the consequence and likelihood of risk. In this study, decommissioning stages, processes, and activities are organized under a work breakdown structure. Potential accidents in the decommissioning process of NPPs are analyzed using the composite risk matrix to assess both radiological and non-radiological hazards. The levels of risk for all potential accidents considered by U.S. NPP operators who have performed decommissioning were estimated based on their consequences and likelihood of events.

• Safety and Health at Work
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• 제8권3호
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• pp.267-275
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• 2017

Background: The mining industry is known worldwide for its highly risky and hazardous working environment. Technological advancement in ore extraction techniques for proliferation of production levels has caused further concern for safety in this industry. Research so far in the area of safety has revealed that the majority of incidents in hazardous industry take place because of human error, the control of which would enhance safety levels in working sites to a considerable extent. Methods: The present work focuses upon the analysis of human factors such as unsafe acts, preconditions for unsafe acts, unsafe leadership, and organizational influences. A modified human factor analysis and classification system (HFACS) was adopted and an accident predictive fuzzy reasoning approach (FRA)-based system was developed to predict the likelihood of accidents for manganese mines in India, using analysis of factors such as age, experience of worker, shift of work, etc. Results: The outcome of the analysis indicated that skill-based errors are most critical and require immediate attention for mitigation. The FRA-based accident prediction system developed gives an outcome as an indicative risk score associated with the identified accident-prone situation, based upon which a suitable plan for mitigation can be developed. Conclusion: Unsafe acts of the worker are the most critical human factors identified to be controlled on priority basis. A significant association of factors (namely age, experience of the worker, and shift of work) with unsafe acts performed by the operator is identified based upon which the FRA-based accident prediction model is proposed.

• Korean Management Science Review
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• 제28권3호
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• pp.61-72
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• 2011

This study suggests a DEA(Data Envelopment Analysis) based model to evaluate the value of corporate stock. The model integrating PER(Price-Earning Ratio), PBR(Price-BookValue Ratio), PSR(Price-Sales Ratio) and volatility in DEA structure has an advantage of overcome the limitation of traditional financial ratio based models. In order to show the effectiveness of the suggested model. we compare the performance of portfolio composed by DEA approach with those of portfolios made by traditional approaches such as PER, PBR, and PSR in terms of stock return and volatility. Specifically, we use the data of all the enterprises listed on the S&P 500 in the U.S. in 2007 and 2009 as the sample data for the experiments. The results of the experiments show that the performance of the DEA approach is clearly better than those of other approaches. Particularly, in sharply plummeting market, the performance of the DEA approach is shown to be prominently better than those of other approaches as the DEA approach reflects investment risk as well as profitability and growth. The DEA score combining the existing investment indices may serve as a useful barometer for selecting a stable and profitable portfolio.