• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.11
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• pp.2089-2092
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• 2010

There are many cases that interrupt the production process because of malfunctions caused by electronic circuit boards which control equipment, but it is difficult to distinctly identify the causes in many cases. Especially, CMOS devices with the control logic circuit return automatically to normal state after their own faults. Therefore it is not easy to analyze the problems with electronic circuit boards. Recently, nuclear power plant experienced a failure due to the malfunction of electronic circuit boards and it was identified that the reason of the malfunction was because of latch-up phenomenon caused by external surge in electronic devices. This paper presents the causes and the phenomenon of latch-up by experiment and also a way using counter EMF diodes, noise filters and surge protective devices to prevent latch-up phenomenon from electronic circuit boards, finally confirms the effectiveness of the result by experiment.

• Journal of the Korean Society of Clothing and Textiles
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• v.44 no.3
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• pp.516-538
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• 2020

The present study investigated regional and sex differences in knowledge, perception, cognition and behavior of fine-dust protective masks for periods of high concentration of fine dust in Korea. A total of 2,012 adults from seven provinces responded to the questionnaire. The results (all p<.05) showed that 78% of respondents considered pollution from China to be the greatest contributor of fine dust. Seoul and Gyeonggi residents more frequently checked fine dust forecasts than other provinces and consulted their smartphone applications to do so more than other residents. Jeju, Gwangwon, and Jeonla residents had less knowledge of KF 80, 94, and 99 masks than residents of other provinces. Gwangwon and Jeju residents had less trust in the effectiveness of protective masks than other residents. Females perceived themselves as unhealthier respiratory, more frequently checked the concentration of fine dust, trusted more the effectiveness of masks, and more frequently wore masks, compared to male respondents. Those who self-identified their respiratory function as poor, more frequently checked fine dust forecasting, and had greater knowledge of masks, which resulted in greater trust in the protective function of masks, and finally had higher wear frequency of masks for days with high concentrations of fine dust.

• Asia-Pacific Journal of Business
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• v.12 no.1
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• pp.71-86
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• 2021

Purpose - This study examines the awareness regarding the symptoms of COVID-19 exposures and safety distances strategies whether they were useful to resile the businesses a mid of the pandemic. Besides exploring the awareness and safety distances, the effectiveness of offering free use of protective equipment (mask, hand sanitizer, frequent hand washing, etc.) to the customers for visiting the business centers was also examined. Design/methodology/approach - This study collected 264 survey data in Bangladesh which is one of the most densely populated country and very vulnerable for COVID-19 due to its socio-economic condition. The multiple regression analysis is used to analyze the data. Findings - The findings of the study indicate that the awareness about the symptoms of virus exposures (cough, fever, diarrhea, and weakness) has significant affirmative effects to enhance the public movement for business purposes with the lower possibility to be affected by the virus. The study also indicates that safety distances and protective equipment can mediate the significant positive relationship between the awareness of the disease and the businesses' resilient capacity. Research implications or Originality - COVID-19, as an apprehensive health issue in the current world, has sharpened the uncertainty of the businesses. One essential technique as lockdown, has been followed by almost every country to protect the transmission of the virus even though the scholars criticized it due to the substantial adverse effects on the country's economy. Under this circumstances, this study provides implications to the relevant businesses by assessing the nexus between the safety distances and the proper uses of protective equipment with the business resilient.

• Proceedings of the Korea Contents Association Conference
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• 2017.05a
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• pp.111-112
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• 2017

MRI는 부분 영역을 자세히 영상화하는 검사임에도 인체에 위해한 RF를 전신에 주고 있다. 이러한 문제점을 개선하기 위해 저자들은 RF차단 방호복을 자제제작하여 적용한 결과 적용 전보다 적용 후가 95% 이상 RF를 차단하였다. 따라서 MRI 검사 시 본 연구의 방호복이 인체의 위해를 줄일 수 있는 최적의 대안임을 알 수 있다.

• The Korean Journal of Applied Statistics
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• v.9 no.1
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• pp.1-15
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• 1996

This paper discusses the effectiveness of an infection rate under a certain disease on an immunity rate by a protective inoculation. A sequence of dependense models concerning the infection rate is derived by defining conditionally nested binary random variables for the analysis of polytomous data with hierarchical response scale. Maximum likelihood estimates based on the marginal log-likelihood functin are obtained numerically in the Nelder and Mead's(1965) simplex method.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.2
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• pp.135-143
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• 1991

The setting problem of protective devices in power distribution systems is a combinatorial search problem involving a lot of trial & errors to search for a proper solution which has a great impact for the system reliability. This paper discusses the nature of the problem and proposes a scheme to prune the decision tree achieving the efficient search for a setting solution by applying heuristic rules which utilize pattern informations of backup and primary devices. Its effectiveness is demonstrated through many tests on real systems.

• Biomedical Science Letters
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• v.28 no.2
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• pp.67-82
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• 2022

The prevalence of SARS-CoV-2 led to inconsistent public health policies that resulted in COVID-19 containment failure. These factors resulted in increased hospitalization and death. To prevent viral spread and achieve herd immunity, the only safe and effective measure is to provide to vaccinates. Ever since the release of the SARS-CoV-2 nucleotide sequence in January of 2020, research centers and pharmaceutical companies from many countries have developed different types of vaccines including mRNA, recombinant protein, and viral vector vaccines. Prior to initiating vaccinations, phase 3 clinical trials are necessary. However, no vaccine has yet to complete a phase 3 clinical trial. Many products obtained "emergency use authorization" from governmental agencies such as WHO, FDA etc. The Korean government authorized the use of five different vaccines. The viral vector vaccine of Oxford/AstraZeneca and the Janssen showed effectiveness of 76% and 66.9%, respectively. The mRNA vaccine of Pfizer-BioNTech and Moderna showed effectiveness of 95% and 94.1%, respectively. The protein recombinant vaccine of Novavax showed an effectiveness of 90.4%. In this review, we compared the characteristics, production platform, synthesis principles, authorization, protective effects, immune responses, clinical trials and adverse effects of five different vaccines currently used in Korea. Through this review, we conceptualize the importance of selecting the optimal vaccine to prevent the COVID-19 pandemic.

• Journal of Radiation Protection and Research
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• v.19 no.2
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• pp.109-120
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• 1994

A method for estimating the effectiveness of each protective action against a nuclear accident has been proposed using the fuzzy set theory. In most of the existing countermeasure models in actions under radiological emergencies, the large variety of possible features is simplified by a number of rough assumptions. During this simplification procedure, a lot of information is lost which results in much uncertainty concerning the output of the countermeasure model. Furthermore, different assumptions should be used for different sites to consider the site specific conditions. Tn this study, the diversity of each variable related to protective action has been modelled by the linguistic variable. The effectiveness of sheltering and evacuation has been estimated using the proposed method. The potential advantage of the proposed method is in reducing the loss of information by incorporating the opinions of experts and by introducing the linguistic variables which represent the site specific conditions.

• The korean journal of orthodontics
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• v.49 no.4
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• pp.246-253
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• 2019

Objective: To evaluate the effectiveness of three different caries-preventing agents on artificial caries in a Streptococcus mutans-based caries model. Methods: Sixty-five caries-free human molar enamel blocks were treated with a demineralization solution and a remineralization solution. The specimens were assigned to the following groups according to the caries-protective product applied: group A, chlorhexidine varnish; group B, fluoride-releasing chemically cured sealant; group C, fluoride-releasing lightcured sealant; group D, positive control (specimens that were subjected to de- and remineralization cycles without treatment with any caries-protective agents); and group E, negative control (specimens that were not subjected to de- and remineralization cycles). Samples in groups A-D were stored in demineralization solution with S. mutans and thereafter in artificial saliva. This procedure was performed for 30 days. Average fluorescence loss (${\Delta}F$) and surface size of the lesions were measured using quantitative light-induced fluorescence at baseline and on the 7th, 14th, and 30th days. Results: After 30 days, group A demonstrated a significant increase in ΔF and the surface size of the lesions, no significant difference in comparison with the positive control group, and a significant difference in comparison with the negative control group. Group B showed no significant changes in both parameters at any of the measurement points. While group C showed increased ${\Delta}F$ after 14 days, no significant fluorescence change was observed after 30 days. Conclusions: Both fluoride-releasing sealants (chemically or light-cured) show anti-cariogenic effects, but the use of chlorhexidine varnish for the purpose of caries protection needs to be reconsidered.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.4
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• pp.28-34
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• 2012

Installing surge protection devices for a low-voltage system is important to ensure the survival of electric or electronic devices and systems. If surge protection devices (SPD) are installed without consideration of the concept of lightning protection zones, the equipment to be protected might be damaged despite the correct energy coordination of SPDs. This damage is induced by the reflection phenomena on the cable connecting an external SPD and the load protected. These reflection phenomena depend on the characteristics of the output of the external SPD, the input of the loads, and the cables between the load and the external SPD. Therefore, the SPD has an effective protection distance under the condition of the specific load and the specific voltage protection level of SPD. In this paper, PSCAD/EMTDC software is used to simulate the residual voltage characteristics of SPD Entering the low-voltage device. And by applying a certain voltage level, the effective protection distances of SPD were analyzed according to the each load and length of connecting cable, and the effectiveness of SPD were verified.