• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.9
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• pp.1350-1358
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• 2001

During the last decade, a number of experiments and numerical analyses had been performed in conjunction with the development of simplified analytical methods to estimate the fracture behavior of cracked piping in nuclear power plant. However, the necessity of further investigation for the analytical methods was issued because of the discrepancies with the experimental data. The objective of this paper is to find out the optimum methods to evaluate the load-carrying capacities for cracked pipes. To do this, numerous analytical and finite element analyses were carried out for various pipe and crack geometries and materials. These results were synthesized for crack shapes and can be used as basic data for leak before analyses and risk informed inspections.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.309-314
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• 2007

Recently, the LRFD and the PSF based on structural reliability assessment have been applied to NPP designs in behalf of the conventional deterministic design methods. In the risk-informed structural integrity, it is especially possible to optimize design procedures considering cost, manufacturing and maintenance because the structural reliability concepts have confirmed the reliability for which a designer aims. Generally, in order to evaluate the PSF, the LRFD which is the design concept for evaluating safety factors respectively on the limit state function including load and resistance. This study certifies the concept and its applications of the PSF using the LRFD based on the structural reliability engineering.

• Journal of Korean Society on Water Environment
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• v.28 no.2
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• pp.305-312
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• 2012

Avian influenza (AI) and foot and mouth disease (FMD) are two main contagious pathogenic viruses causing massive mortality burial, as burial is a primary measure to quaranteen the causative viruse(s). Biosecurity is a set of preventive measures designed to reduce the risk of propagation of infectious diseases. Main objectives of this paper were to discuss the needs of biosecurity and develop protocol outlines for environmental management of burial sites. Pathological characteristics of contagious viruses should be considered during environmental management practices. Current practice prescribes to minimize the potential for on-farm pollution and the spread of infectious diseases, policy makers should understand robust knowledge regarding biosecurity to make informed decisions on future legislation.

• Proceedings of the Korean Reliability Society Conference
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• 2000.11a
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• pp.279-285
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• 2000

In Korea, as risk informed applications and regulations become active, the necessity of Maintenance Rule(MR) has increased. The objective of this study is to understand the effectiveness and the application method of the Maintenance Rule, which is one of the performance-based regulations and to propose the effective maintenance and regulation method. Also, Periodic Safety Assessment (PSR) and Reliability Centered Maintenance (RCM) are introduced a little.

• Nuclear Engineering and Technology
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• v.41 no.4
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• pp.391-402
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• 2009

This paper introduces the development of safety assessment technology in Korea, focusing on the activities of the Korea Atomic Energy Research Institute in the areas of system thermal hydraulics, severe accidents and probabilistic safety assessment. In the 1970s and 1980s, safety analysis codes and methodologies were introduced from the United States, France, Canada and other developed countries along with technology related to the construction and operation of nuclear power plants. The main focus was on understanding and utilizing computer codes that were sourced from abroad up to the early 1990s, when efforts to develop domestic safety analysis codes and methodologies became active. Remarkable achievements have been made over the last 15 years in the development and application of safety analysis technologies. In addition, significant experimental work has been performed to verify the safety characteristics of reactors and fuels as well as to support the development and validation of analysis methods.

• Nuclear Engineering and Technology
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• v.37 no.3
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• pp.221-230
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• 2005

This paper reviews the pivotal phases of the evolution of the current technology-dependent nuclear power safety regulation in the United States. Understanding of this evolution is essential to the development of any future regulatory paradigm, including the technology-neutral regulatory approach that the U.S. Nuclear Regulatory Commission (NRC) has recently embarked on to develop. The paper proposes and examines the implications of a predominately rationalist and best-estimate probabilistic regulatory framework called safety goals-driven performance-based regulation. This framework relies on continuous assessment of performance of a set of time-dependent safety-critical systems, structures and components that assure attainment of a broad set of technology-neutral protective, mitigative, and preventive goals. Finally, the paper discusses the steps needed to develop a corresponding technology-neutral regulatory system from the proposed framework.

• International Journal of Reliability and Applications
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• v.4 no.4
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• pp.183-190
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• 2003

Rail breaks and derailments can cause a huge loss to rail players due to loss of service, revenue, property or even life. Maintenance has huge impact on reliability and safety of railroads. It is important to identify factors behind rail degradation and their risks associated with rail breaks and derailments. Development of mathematical models is essential for prediction and prevention of risks due to rail and wheel set damages, rail breaks and derailments. This paper addresses identification of hazard modes, estimation of probability of those hazards under operating, curve and environmental condition, probability of detection of potential hazards before happening and severity of those hazards for informed strategic decisions. Emphasis is put on optimal maintenance and operational decisions. Real life data is used for illustration.

• Journal of Oral Medicine and Pain
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• v.44 no.1
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• pp.31-34
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• 2019

The aim of this case report is to present a case of 68-year-old male with a history of multiple myeloma and the intravenous use of Zometa (zoledronic acid) who had developed medication-related osteonecrosis of the jaw (MRONJ) following a hot pizza burn to the palate. Clinical and radiographic findings revealed grade 1 MRONJ of the right side of the hard palate. Soft tissue trauma and delayed epithelialization may be associated with some cases of MRONJ. Patients on anti-resorptive medications or anti-angiogenic drugs should be informed of the risk of bone exposure and subsequent MRONJ secondary to physical/chemical insults to the bone and soft tissue in the oral cavity.

• International conference on construction engineering and project management
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• 2013.01a
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• pp.122-128
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• 2013

Computer simulations designed to predict technical and financial returns of wind turbine installations are used to make informed investment decisions. These simulations used fixed values to represent real-world variables, while the actual projects can be highly uncertain, resulting in predictions that are less accurate and less useful. In this article, by modifying a popular wind power simulation sourced from the American Wind Energy Association to use Monte Carlo techniques in its calculations, the authors have proposed a way to improve simulation usability by producing probability distributions of likely outcomes, which can be used to draw broader, more useful conclusions about the simulated project.

• Journal of Gastric Cancer
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• v.21 no.4
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• pp.368-378
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• 2021

Purpose: When patients with early gastric cancer (EGC) undergo non-curative endoscopic submucosal dissection requiring gastrectomy (NC-ESD-RG), additional medical resources and expenses are required for surgery. To reduce this burden, predictive model for NC-ESD-RG is required. Materials and Methods: Data from 2,997 patients undergoing ESD for 3,127 forceps biopsy-proven differentiated-type EGCs (2,345 and 782 in training and validation sets, respectively) were reviewed. Using the training set, the logistic stepwise regression analysis determined the independent predictors of NC-ESD-RG (NC-ESD other than cases with lateral resection margin involvement or piecemeal resection as the only non-curative factor). Using these predictors, a risk-scoring system for predicting NC-ESD-RG was developed. Performance of the predictive model was examined internally with the validation set. Results: Rate of NC-ESD-RG was 17.3%. Independent pre-ESD predictors for NC-ESD-RG included moderately differentiated or papillary EGC, large tumor size, proximal tumor location, lesion at greater curvature, elevated or depressed morphology, and presence of ulcers. A risk-score was assigned to each predictor of NC-ESD-RG. The area under the receiver operating characteristic curve for predicting NC-ESD-RG was 0.672 in both training and validation sets. A risk-score of 5 points was the optimal cut-off value for predicting NC-ESD-RG, and the overall accuracy was 72.7%. As the total risk score increased, the predicted risk for NC-ESD-RG increased from 3.8% to 72.6%. Conclusions: We developed and validated a risk-scoring system for predicting NC-ESD-RG based on pre-ESD variables. Our risk-scoring system can facilitate informed consent and decision-making for preoperative treatment selection between ESD and surgery in patients with EGC.