• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.3
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• pp.233-239
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• 2017

The CA (Control Assembly) of an SFR has a CRA(Control Rod Assembly) with an inner duct and control rod. During an emergency situation, the CRA falls into the duct of the CA for a rapid shut-down. The drop time and impact velocity of the CRA are important parameters with respect to the reactivity insertion time and the structural integrity of the CRA. The objective of this study was to investigate the dynamic behavior and integrity of the CRA owing to a drop impact. The impact analysis of the CRA under normal/abnormal drop conditions was carried out using the commercial FEM code LS-DYNA. Results of the drop impact analysis demonstrated that the CRA maintained structural integrity, and could be safely inserted into the flow hole of the damper under abnormal conditions.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.12
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• pp.1543-1548
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• 2011

Structural analysis is performed to design anchor straps for a large-scale-liquefied-natural-gas (LNG) storage tank with corner protection and an inner tank by considering structural integrity. Anchor straps made of 9% nickel steel are attached to the inner tank, corner protection, and concrete raft to prevent the failure of the inner tank during both normal and emergency operating conditions. Two finite element (FE) models were analyzed in this study. One is a stand-alone model of the anchor strap, while the other is an extended model of the substructure of the anchor strap, inner tank, and corner protection. Three-dimensional shell elements are used to effectively assess the bending and axial behavior of structures. The Tresca stress values in each part of the two models are calculated for operation under five different load-condition cases: normal operation, leakage of the LNG, hydro test, and two earthquake conditions.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.2
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• pp.149-156
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• 2005

In this paper, the VR(Virtual Reality) simulation system is developed to analyze driver's perceptive response on the ASV(Advanced Safety Vehicle). The ASV is the vehicle of next generation equipped with various warning systems. For the purpose, the VR simulation system consists of VR database, vehicle dynamic model, graphic/sound system, and driving system. The VR database which generates 3D graphic and sound information is organized for the driving reality. Mathematical models of vehicle dynamic analysis are constructed to represent the dynamic behavior of a vehicle. The driving system and the graphic/sound system provide a driver with the operation of a vehicle and the feedback of a driving situation. Also, the real-time simulation algorithm synchronizes the vehicle dynamic model with the VR database. To check the validity of the developed system, a simple scenario is applied to investigate driver's perceptive response time and vehicle acceleration on an emergency situation. It is confirmed that the proposed system is useful and helpful to design the FVCWS(Forward Vehicle Collision Warning System).

• Fire Science and Engineering
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• v.33 no.4
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• pp.70-76
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• 2019

This paper reports development of a low-power standalone heat detector using a Critical-Temperature Switch. The Critical-Temperature Switch, which is a thermally sensitive and passive component whose resistance decreases significantly at 70 ℃ due to a metal-insulator transition, provides reliable temperature measurements. This digital-like behavior of the Critical-Temperature Switch can detect fires without a microcontroller, meaning that it can minimize the power consumption of the standalone heat detector. The experimental results showed that the standalone heat detector using the Critical-Temperature Switch complied with the Notification of the National Emergency Management Agency. Compared to conventional standalone heat detectors, only 70% of the power was consumed monitoring the fires.

• Nuclear Engineering and Technology
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• v.25 no.1
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• pp.37-50
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• 1993

To evaluate the sequence of event and the Thermohydraulic behavior during total loss of feedwater accident and recovery procedure, a RELAP5/MOD3 calculation is performed and compared with the LOFT L9-l/L3-3 experiment. Also, the predictability of the code for the major Thermohydraulic phenomena following the accident is assessed. As a result, it is found that a pressure control using the spray until the time the water level reaches the top of the pressurizer, an overpressure protection by pressurizer PORV, a recovery of the secondary heat removal capability by refilling steam generator, and an effective cooldown by the continued natural circulation can be performed without core uncovery. It is also found that the plant-specific evaluation is necessary to confirm the effectiveness of the current symptom-oriented emergency operating procedure, especially in an overpressure protection performance and steam generator recovery performance.

• Korean Journal of Clinical Pharmacy
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• v.23 no.3
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• pp.269-277
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• 2013

Objectives: The purpose of this study was to identify the factors which affect risk perception and attitude on government risk management over medications containing asbestos among parents of elementary school students. Methods: This research design was cross-sectional study using self-administered questionnaire. The survey subjects were parents of elementary school students in Seoul, total of 1,051 subjects. The survey period was from June through July of 2011. The collected data were analyzed using the SPSS 20.0. Results: The subjects perceived high risk regarding medications containing asbestos. About 83.6% of the subjects perceived that the result taking of medications containing asbestos was fatal, 82.8% felt that medications containing asbestos was a very serious social problem, 79.5% agreed that medications containing asbestos was a new type of threat. The risk perception for medications containing asbestos was related to political affiliation, attitudes of dealing medicines, main use of media, and personal communication credibility. Those who did not believe that the current government policy was correct and the government was working toward the public's benefit and not its own had the higher level of negative attitudes towards the government's risk management over the case of medications containing asbestos. Conclusion: In implementing government policy, all information should be efficiently and accurately communicated through a transparent implementation process. Also, the government must have plans for countermeasures in case of an emergency and respond efficiently in order to maintain their credibility. Moreover, this highlights the need for health authorities to exert more effort in increasing public education/awareness, especially those concerning drug and dug-taking behavior, in order to harness positive attitude and trust towards the government's policy. For a more effective risk communication, the media, health experts, government representatives, and related industries should work together.

• Journal of Korean Institute of Fire Investigation
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• v.10 no.1
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• pp.59-75
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• 2007

The causes of the fire casualties were the heat burns, contacted by flame, before the period of industrialization. According to the economic has been developed drastically since 1990, residing space has been become bigger and sophistication and interior finishing materials have been diversified. Therefore, the suffocation casualties, caused by inspiration of toxic combustion gases, have been more increased than the flame casualties in recently. Also, the arson casualties have been increasing with the increasing of insurance crime to take the Insurance money. According to National Emergency Management Agency announcement, 31,778 fires was occurred nationwide in 2006 and the total casualties were 2,180 occurred. 446 persons were died among them. Because the exact investigation of fire, occurred the death, is very especially important that civil and criminal cases will be happened. Therefore, we studied about the cause of fire, the place of origin, and the group of casualties age on the axies of fires, which were occurred recently. And the identification method of fire casualties, the human behavior characteristic, the flame casualties and the suffocation casualties at fire scene.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.1
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• pp.1-10
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• 2008

A transient 3-D numerical simulation was performed to analyze the fire safety in a railway tunnel equipped with a mechanical ventilation system. The behavior of pollutants was studied for the emergency operation mode of ventilation system in case of fire in the center of the rescue station and near the escape route. Various schemes of escape route construction for connection angle($45^{\circ}$, $90^{\circ}$, 135^{\circ}$) and slope($10^{\circ}$) were evaluated for the ventilation efficiency in the fire near the escape route. From the results, it was shown that the mode of the ventilation fan operation which pressurizes the tunnel not under the fire and ventilates the smoke from the tunnel under the fire is most effective for the smoke control in the tunnel in case of the fire occurrence. It was also shown that the blowing of jet fan from the rescue tunnel to the main tunnel should be in the same direction as the flow direction in the main tunnel arising from the traffic and the buoyancy.

• Journal of Korean Clinical Nursing Research
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• v.17 no.2
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• pp.239-250
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• 2011

Purpose: This study was aimed to evaluate the effects of Labor Support Behaviors (LSB) one-to-one application and partner's delivery participation on the delivery satisfaction and delivery results among mothers who delivered premature birth and low birth weight infant. Methods: The data were collected from 30 mothers in the experimental group and 27 in the control group from April 23, 2009 to April 22, 2010. The collected data were analyzed using percentage, mean, standard deviation, $x^2-test$ (Fisher's exact test) and t-test with SPSS. Results: The satisfaction levels of the experimental group and the control group women were $3.73{\pm}0.43$ and $3.72{\pm}0.34$ as mean values, respectively, showing not statistically different (t=0.07, p=.945). None showed less than 7 point of Apgar score at 1 minute in the experimental group while 5 out of 27 did (18.5%) in the control group, which was statistically meaningful. Also, the emergent cesarian section cases were 3 out of 33 (9.1%) in the experimental group and 5 out of 32 (15.6%) in the control group, demonstrating lower emergency cesarian section rate in the experimental group than the control group, but showing not statistically different ($x^2=0.643$, p=.475). Conclusion: The results of this study show that LSB one-to-one application and partner's participation has affirmative effects on 1 minute Apgar scores of newborns.

• Anxiety and mood
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• v.17 no.2
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• pp.78-83
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• 2021

Objective : Current study investigated the association between internet addiction and suicidal attempts in psychiatric patients. Methods : Patients who visited emergency department or psychiatry outpatient unit of Chungnam National University Hospital from January 2020 to July 2021 were included in this study. Total of 192 participants, 96 suicidal attempt cases and 96 psychiatric control patients without history of suicidal attempt were matched by gender and baseline diagnosis. Depression and internet addiction were assessed by using Patient Health Questionnaire-9 (PHQ-9) and Young's Internet Addiction Test (IAT). Independent t-tests, and logistic regression analyses were conducted. Results : IAT scores were significantly higher in suicidal attempt case group (41.09±18.196 years) compared to psychiatric control patients without history of suicidal attempt (36.63±17.016 years) (p=0.040). Internet addiction (adjusted Odds Ratio [aOR]=2.049, 95% Confidence Interval [CI]=1.004-4.539, p=0.0493) was an independent risk factor for suicidal attempt in psychiatric patients after controlling age, gender, and sociodemographic factors, such as marital status, education level and employment status. Conclusion : This is the first study to investigate the relationship between internet addiction and suicidal attempt in psychiatric patients in Korea. Internet addiction is significantly associated with suicidal attempt in psychiatric patients, after adjusting sociodemographic variables. This study provides evidence to future studies to further investigate on causality of internet addiction and suicidality in psychiatric patients.