• Proceedings of the KIEE Conference
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• summer
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• pp.113-116
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• 2004

Many methods to examine the vulnerable areal for the contingencies in the power system. The most widely used index for the vulnerable area investigation has been the reactive power margin or sensitivity analysis. But we can get the results of these analyses if only the results of load flow are convergent in severe contingencies, otherwise these methods are not adoptable. We can present a good index for overcoming severe contingencies, if we can get the vulnerable areas by bus sensitivity in severe contingencies, though the power flow equation is unsolvable. This paper simulates unsolvable severe contingencies by using branch parameter continuation power flow. We can compute the vulnerable areas in unsolvable severe contingencies by normal vector at a nose point of a $\nu-V$ curve. Presented method is checked the input reactive power of the vulnerable areas in KEPCO system.

• Korean Journal of Clinical Pharmacy
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• v.14 no.1
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• pp.32-35
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• 2004

The purpose of this study was to investigate the pharmacokinetic changes of verapamil in rabbits with hepatic disorder induced by carbon tetrachloride. The plasma concentrations of verapamil were increased significantly (p<0.05, in slight group; P<0.01, in moderate and severe group) in all groups of hepatic disorder compared to the control group. Morover, the $C_{max}\;in\;slight\;(77.9\%$ increase), moderate ($110\%$ increase), and severe ($174\%$ increase) hepatic disorder groups were significantly (p<0.05, in slight; p<0.01, in moderate and severe) higher than that in control rabbits. These resulted in significantly (p<0.05, in slight; p<0.01, in moderate and severe) greater area under the plasma concentration-time curve (AUC) in moderate ($49.8\%$ increase), moderate ($95.0\%$ increase), and severe ($144\%$ increase) hepatic disorder groups than that in control rabbits. Hence, the relative bioavailability values were 149, 195, and $244\%$ for slight, moderate, and severe hepatic disorder groups, respectively. This could be due to decrease in metabolism of verapamil in the liver because of suppressed hepatic function in the hepatic disorder groups because verapamil is mainly metabolized in the liver.

• Nuclear Engineering and Technology
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• v.47 no.2
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• pp.139-147
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• 2015

Recently, severe accidents in nuclear power plants (NPPs) have become a global concern. The aim of this paper is to predict the hydrogen buildup within containment resulting from severe accidents. The prediction was based on NPPs of an optimized power reactor 1,000. The increase in the hydrogen concentration in severe accidents is one of the major factors that threaten the integrity of the containment. A method using a fuzzy neural network (FNN) was applied to predict the hydrogen concentration in the containment. The FNN model was developed and verified based on simulation data acquired by simulating MAAP4 code for optimized power reactor 1,000. The FNN model is expected to assist operators to prevent a hydrogen explosion in severe accident situations and manage the accident properly because they are able to predict the changes in the trend of hydrogen concentration at the beginning of real accidents by using the developed FNN model.

• Journal of Distribution Science
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• v.18 no.11
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• pp.91-103
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• 2020

The recent Covid-19 outbreak has caused severe disruption of the global supply chain, which tests firms' ability to survive and build resilience. The concept of adaptive supply chain management (A-SCM) has never been tested against a severe supply chain disruption, such as a pandemic. Purpose: The aim of this study is to examine how firms in Indonesia develop resilience through the implementation of components of adaptive supply chain management, namely risk management, resource reconfiguration and supply chain flexibility, in order to survive severe supply chain disruption. Research design, data and methodology: A qualitative method and PLS-SEM were used to analyze 120 data collected from Indonesian manufacturing firms in various industries. Results: The findings show that risk management, resource reconfiguration, and supply chain flexibility are important components that make up A-SCM. However, only risk management contributes to help build firm resilience in the presence of severe supply chain disruption. Conclusions: The components of A-SCM have been empirically tested. The implication is that managers should carefully use RM to prepare firms for different scenarios to develop contingency strategies. This research contributes to the supply chain management body of knowledge in the context of pandemic-level disruption and broadens the dynamic capabilities perspective.

• Nuclear Engineering and Technology
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• v.47 no.1
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• pp.66-73
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• 2015

Background: A numerical simulation was carried out to investigate the difference between internal and external heat-flux distributions at the reactor vessel wall under in-vessel retention through external reactor vessel cooling (IVR-ERVC). Methods: Total loss of feed water, station blackout, and large break loss of coolant accidents were selected as the severe accident scenarios, and a transient analysis using the element-birth-and-death technique was conducted to reflect the vessel erosion (vessel wall thickness change) effect. Results: It was found that the maximum heat flux at the focusing region was decreased at least 10% when considering the two-dimensional heat conduction at the reactor vessel wall. Conclusion: The results show that a higher thermal margin for the IVR-ERVC strategy can be achieved in the focusing region. In addition, sensitivity studies revealed that the heat flux and reactor vessel thickness are dominantly affected by the molten corium pool formation according to the accident scenario.

• Atmosphere
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• v.29 no.5
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• pp.609-614
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• 2019

Cloud seeding experiment has been proposed as a way to alleviate severe air pollution problem because, if successful, artificially produced precipitation through cloud seeding could scavenge out some portion of air pollutants. As a first step to verify the practicality of such experiment, seedability of the clouds observed in Seoul is assessed by examining statistical characteristics of some relevant meteorological variables. Analyses of 9 years of Korea Meteorological Agency Seoul station data indicate that as PM₁₀ mass concentration increases, cloud amount, liquid water path, and ice water path decrease, but the difference between temperature and dew point temperature tends to increase. Such finding suggests that cloud seeding becomes less feasible as air pollution becomes more severe in the Seoul metropolitan area, at least in a statistical sense. For some individual severe air pollution events, however, seedable clouds may exist and indeed cloud seeding experiments can be successful. Therefore, detailed investigation on cloud seedability for individual severe air pollution events are highly required to make a concrete assessment of cloud seeding as a way to alleviate severe air pollution problem.

• Journal of Korean Foot and Ankle Society
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• v.2 no.1
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• pp.42-47
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• 1998

The conventional surgical treatment for deformed foot has always consisted of massive soft tissue releases combined with varying methods of osteotomies and fusions to plantigrade functional foot. But, the resulting feet have often been foreshortened, stiff, and nothing more than a cosmetically acceptable but functionally poor foot. Now the techniques of distraction histogenesis has been given a new tool to apply to the complex foot deformity. We have recently experienced two cases of severe deformed feet and treated with Ilizarov technique. One patient had postcompartmental severe rigid equinocavovarus foot. And the other had traumatic severe rigid metatarsus abductus. The follow up periods were 14 and 28 months respectively. The feet were aesthetically pleasing. So, we believed that the Jlizarov technique is an excellent treating method for severe deformed foot.

• Investigative and Clinical Urology
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• v.59 no.6
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• pp.399-409
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• 2018

Purpose: To analyze data from an observational, prospective, cumulative registry study in 805 hypogonadal men stratified by mild or moderate-to-severe lower urinary tract symptoms (LUTS) according to International Prostate Symptom Score. Materials and Methods: A total of 412 men underwent testosterone therapy (TTh) with injectable testosterone undecanoate, 393 men served as untreated controls. Measures of urinary function, anthropometric and metabolic parameters were performed at least twice per year. Results: Data from 615 men with mild LUTS (253 treated, 362 untreated) and 190 with moderate-to-severe LUTS (159 treated, 31 untreated) were available. During a follow-up period of 8 years a significant improvement of LUTS was noted for all TTh-patients whereas the control-groups showed deterioration or fluctuation around initial values. Despite advancing age, TTh fully prevented worsening of symptoms. In parallel, a considerable improvement of anthropometric parameters, lipids and glycemic control, blood pressure, C-reactive protein, and quality of life was found. Moderate-to-severe LUTS was associated with worse cardiometabolic risk profile at baseline as well as worse cardiovascular outcomes during follow-up in comparison to mild LUTS. Effect size of TTh was more pronounced in men with moderate-to-severe than with mild LUTS. Conclusions: Correcting hypogonadism by TTh is highly effective and safe for improving LUTS in hypogonadal men. TTh may also improve cardiometabolic risk and major adverse cardiovascular events.

• The Korean Journal of Emergency Medical Services
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• v.22 no.3
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• pp.163-176
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• 2018

Purpose: The purpose of this study was to determine the effectiveness of hands-only CPR education according to the American Heart Association (2015) guideline for undergraduates with severe visual impairment, to provide basic data for expanding the subject of hands-only CPR education among the visually impaired. Methods: Twenty-one students attending four universities in C Province, aged 19 years or older, were enrolled in this study. These students had severe visual impairment and no other disabilities and have never received hands-only CPR education. This study data were collected from December 1, 2017 to January 11, 2018. The accuracy of the participants' technique was measured using Brayden Pro CPR manikin. The data were analyzed using SPSS version 24.0. Results: Hands-only CPR education was effective in increasing confidence and accuracy of chest compression among undergraduates with severe visual impairment. Conclusion: These findings suggest that individuals with severe visual impairment should be given more educational opportunities. Additionally, subsequent studies should develop equipment that helps increase accuracy by using video aids with commentary or other auditory components for the visually impaired.

• Nuclear Engineering and Technology
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• v.54 no.1
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• pp.138-151
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• 2022

Cladding ballooning and rupture are the important phenomena at the early stage of a severe accident. Most severe accident analysis codes determine the cladding rupture based on simple parameter models. In this paper, a FRTMB module was developed using the thermal-mechanical model to analyze the fuel mechanical behavior. The purpose is to judge the cladding rupture with the severe accident analysis code. The FRTMB module was integrated into the self-developed severe accident analysis code ISAA to simulate the PHEBUS FPT3 experiment. The predicted rupture time and temperature of the cladding were basically consistent with the measured values, which verified the correctness and effectiveness of the FRTMB module. The results showed that the rising of gas pressure in the fuel rod and high temperature led to cladding ballooning. Consequently, the cladding hoop strain exceeded the strain limit, and the cladding burst. The developed FRTMB module can be applied not only to rod-type fuel, but also to plate-type fuel and other types of reactor fuel rods. Moreover, the FRTMB module can improve the channel blockage model of ISAA code and make contributions to analyzing the effect of clad ballooning on transient and subsequent parts of core degradation.