• Journal of the Computational Structural Engineering Institute of Korea
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• v.37 no.3
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• pp.205-216
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• 2024

Recently, seismic Probabilistic Safety Assessment (PSA) methods have been developed for process plants, such as gas plants, oil refineries, and chemical plants. The framework originated from the PSA of nuclear power plants, which aims to assess the risk of reactor core damage. The original PSA method was modified to adopt the characteristics of a process plant whose purpose is continuous operation without shutdown. Therefore, a fault tree, whose top event is shut down, was constructed and transformed into a Bayesian Network (BN), a probabilistic graph model, for efficient risk-informed decision-making. In this research, the fault tree-based BN from the previous research is further developed to consider the multi-hazard of earthquake-induced fire and explosion (EQ-induced F&E). For this purpose, an event tree describing the occurrence of fire and explosion from a release is first constructed and transformed into a BN. And then, this BN is connected to the previous BN model developed for seismic PSA. A virtual plot plan of a gas plant is introduced as a basis for the construction of the specific EQ-induced F&E BN to test the proposed BN framework. The paper demonstrates the method through two examples of risk-informed decision-making. In particular, the second example verifies how the proposed method can establish a repair and retrofit strategy when a shutdown occurs in a process plant.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.11
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• pp.4571-4573
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• 2014

Diabetes, a comprehensive genetic disease, is principally due to the deregulation of glucose levels in the blood. In addition to contemporary epidemiological studies, systematic substantiation suggests that long-term diabetes leads to cancers due to a variety of reasons. In this study, blood samples were collected with informed consent from confirmed type I diabetic (T1DM, n=25) and type II Diabetic patients (T2DM, n=25) with equal numbers of controls. Further depending on the lifestyle habits they were subdivided into smokers/non-smokers and alcoholics/non-alcoholics. Chromosomal assays were performed for these cases and it was found that there was a significant increase in chromosomal aberration frequency in diabetic patient groups who are exposed to smoking and alcohol than that of normal diabetic groups (T1DM and T2DM). On the other hand, patient groups who were non-smoking and non-alcoholics also showed higher chromosomal aberrations when compared to that of controls. While the mechanisms for these increased chromosomal aberrations in diabetic groups are not clear, they may be due to increased oxidative stress leading to oxidative damage and resulting in genomic instability, which in turn may contribute to an increased risk for cancer.

• Journal of Korean Dental Science
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• v.2 no.1
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• pp.4-10
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• 2009

Though implant treatment is considered as a common treatment option for edentulous patients, there have been few studies on the temporomandibular disorder (TMD) related with implant treatment. The purposes of this study were to evaluate the relevance of TMD to the implant patients and to evaluate the risk factors of TMD in relation with implant treatment. For the evaluation of various risk factors of TMD in relation with implant therapy, clinical evaluation focused on patient factors and implant factors. From a group of 694 patients, 25 patients (3.6 %) were included in this study. The majority of the patients were included in the asymptomatic 'adaptive' group. Parafunction was detected in 11 patients, 8 patients were male. Four patients having parafunction showed complications such as implant failure or fracture of the suprastructure. From the results, it is possible that TMJ related symptoms are developed or aggravated after implant therapy, which requires relatively more chair time; so TMJ examination should be included in the pre-operative evaluation for dental implant patients. Also, it is important to treat patients after they sign an informed consent that includes a detailed explanation on the possibility of TMD during treatment.

• The Korean Journal of Pain
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• v.10 no.1
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• pp.131-133
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• 1997

Number of elderly patients requiring nerve blocks have been increasing in recent years. We had two elderly patients who suffered stroke one day and three days after lumbar facet joint block and lumbar single epidural block respectively. Both patients due to their advanced age had potential risk factor to suffer one or more of the following; stroke, hypertension, and diabetes mellitus. Due to our experience with these patients, we suggested the following: (1) Nerve blocks should be reconsidered for elderly patient who posesses a potential risk factor to suffer a stroke. (2) Prior to invasive block administration of mild sedatives or analgesics may provide beneficial effects for patients with hypertension. (3) Adequately informed consent must be fully discussed time of consultation with patient scheduled for nerve block especially for elderly and risky patient.

• The Journal of Asian Finance, Economics and Business
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• v.1 no.3
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• pp.5-16
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• 2014

This study aims to examine the dynamics of price changes and trading volume of Kuala Lumpur Options and Financial Futures Exchange (KLOFFE) from 2000 to 2008. With augmented analysis, our results support two hypotheses. First, under information spillover, our findings support noise traders' hypothesis as the time span for variance of past trading volume to cause variance of current return is found to be asymmetric under bull and bear markets. Second, looking at the dynamic relation between volume and volatility of price changes, our findings support Liquidity-Driven Trade hypothesis as past trading volume and subsequent volatility of return exhibit positive correlation. In terms of investors' behavior in response to the news, we find that investors are more risk taking in bull market and more risk reverse in bear market. Our study suggests that investors should adjust their strategy in the futures market in a dynamic manner as the time span of new information arrival is not consistent. Also, uninformed investors with information asymmetry should expect noninformational trading from informed investors to establish their desired positions for better liquid position.

• Safety and Health at Work
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• v.7 no.2
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• pp.143-149
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• 2016

Background: The industrial revolution that took place in the United Kingdom (UK) between 1760 and 1830 led to profound social change. Occupational medicine was concerned with the diagnosis, treatment, and prevention of occupational diseases, that is, diseases directly caused by exposure to workplace hazards. A similar pattern of development has occurred globally. Methods: A review of relevant literature. Results: The international conceptualization and development of occupational health occurred during the 20th century. A new paradigm for occupational health has emerged that extends the classical focus on what might be termed "health risk management" that is, the focus on workplace hazards and risk to health to include the medical aspects of sickness absence and rehabilitation, the support and management of chronic noncommunicable diseases, and workplace health promotion. Conclusion: The future strategic direction for occupational health will be informed by a needs analysis and a consideration of where it should be positioned within future healthcare provision. What are the occupational health workforce implications of the vision for occupational health provision? New challenges and new ways of working will necessitate a review of the competence and capacity of the occupational health workforce, with implications for future workforce planning.

• The Plant Pathology Journal
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• v.35 no.5
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• pp.459-472
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• 2019

The increasing variation in climatic conditions under climate change directly influences plant-microbe interactions. To account for as many variables as possible that may play critical roles in such interactions, the use of an integrated modeling approach is necessary. Here, we report for the first time a local impact assessment and adaptation study of future epidemics of kiwifruit bacterial blossom blight (KBB) in Jeonnam province, Korea, using an integrated modeling approach. This study included a series of models that integrated both the phenological responses of kiwifruit and the epidemiological responses of KBB to climatic factors with a 1 km resolution, under the RCP8.5 climate change scenario. Our results indicate that the area suitable for kiwifruit cultivation in Jeonnam province will increase and that the flowering date of kiwifruit will occur increasingly earlier, mainly due to the warming climate. Future epidemics of KBB during the predicted flowering periods were estimated using the Pss-KBB Risk Model over the predicted suitable cultivation regions, and we found location-specific, periodic outbreaks of KBB in the province through 2100. Here, we further suggest a potential, scientifically-informed, long-term adaptation strategy using a cultivar of kiwifruit with a different maturity period to relieve the pressures of future KBB risk. Our results clearly show one of the possible options for a local impact assessment and adaptation study using multiple models in an integrated way.

• Journal of Korean Neurosurgical Society
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• v.62 no.5
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• pp.586-593
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• 2019

Objective : To study risk factors of secondary lumbar discectomy (LD) for recurrent herniated lumbar disc (HLD) and identify methods to lower the rate of recurrence. Methods : Data from 160 patients who underwent primary LD were collected retrospectively. Demographic features, radiologic findings including Pfirrmann disc degeneration, and surgical information were analyzed to compare risks between revision and non-revision patients. Results : The revision rate was 15% (24 patients), and the mean follow-up was 28.3 months. HLD recurrence was not related to any demographic characteristics. Primary and secondary LD were most common at the L4-5 level, but the level of operation was not significantly associated with revision. Primary LD most commonly had a Pfirrmann disc degeneration grade of 3, followed by 4. For recurrent HLD, Pfirrmann grade 4 was most common and was statistically significant (p<0.05). A body mass index (BMI) over 30 was considered obese and was significantly related with HLD revision (p<0.05). Conclusion : Patients with high BMI or severe disc degeneration should be informed of HLD revision.

• Journal of the Korean Society of Systems Engineering
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• v.17 no.1
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• pp.21-34
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• 2021

The use of Field-Programmable Gate Arrays (FPGAs) in the development of safety-related Human-Machine Interface (HMI) systems has gained much momentum in nuclear applications. Recently, one of the application areas for the Advanced Power Reactor 1400 (APR1400) is in the development of the advanced Component Interface Module (CIM) of the Engineered Safety Features Actuation System (ESFAS). Using systems engineering approach, we have developed a new FPGA-based advanced CIM software. The first step of our software development process involves the Preliminary Hazard Analysis (PHA) based on the previous CIM design. In this paper, we describe the qualitative approach used in performing the preliminary hazard analysis. The paper presents the methodology for applying a modified Hazard and Operability (HAZOP) procedure for the conduct of PHA which resulted in a qualitative risk-ranking scheme that informed the decisions for the safety criteria in the requirements specification phase. The qualitative approach provided the justification for design changes during the advanced CIM software development process.

• Journal of the Korean Society of Safety
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• v.37 no.2
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• pp.43-53
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• 2022

This paper describes an attempt to improve and optimize the operational safety level of a domestic research reactor by conducting a probabilistic safety assessment (PSA) under full-power operating conditions. The PSA was undertaken to assess the level of safety at an operating research reactor in Korea, to evaluate whether it is probabilistically safe and reliable to operate, and to obtain insights regarding the requisite procedural and design improvements for achieving safer operation. The technical objectives were to use the PSA to identify the accident sequences leading to core damage, and to conduct sensitivity analyses based thereon to derive insights regarding potential design and procedural improvements. Based on the dominant accident sequences identified by the PSA, eight types of sensitivity analysis were performed, and relevant insights for achieving safer operation were derived. When these insights were applied to the reactor design and operating procedure, the risk was found to be reduced by approximately ten times, and the safety was significantly improved. The results demonstrate that the PSA methodology is very effective for improving reactor safety in the full-power operating phase. In particular, it is a highly suitable approach for identifying the deficiencies of a reactor operating at full power, and for improving the reactor safety by overcoming those deficiencies.