• Nuclear Engineering and Technology
• /
• 제53권4호
• /
• pp.1236-1249
• /
• 2021

Although there are still controversial opinions and uncertainty on application of SiC_f/SiC composite cladding as next-generation cladding material for its great oxidation resistance in high temperature steam environment and other outstanding advantages, it cannot deny that SiC_f/SiC cladding is a potential accident tolerant fuel (ATF) cladding with high research priority and still in the engineering design stage for now. However, considering its disadvantages, such as low irradiated thermal conductivity, ductility that barely not exist, further evaluations of its in-pile behaviors are still necessary. Based on the self-developed code we recently updated, relevant thermohydraulic and mechanical models in FROBA-ATF were applied to simulate the cladding behaviors under normal and accident conditions in this paper. Even through steady-state performance analysis revealed that this kind of cladding material could greatly reduce the oxidation thickness, the thermal performance of UO₂-SiC was poor due to its low inpile thermal conductivity and creep rate. Besides, the risk of failure exists when reactor power decreased. With geometry optimization and dopant addition in pellets, the steady-state performance of UO₂-SiC was enhanced and the failure risk was reduced. The thermal and mechanical performance of the improved UO₂-SiC was further evaluated under Loss of coolant accident (LOCA) and Reactivity Initiated Accident (RIA) conditions. Transient results showed that the optimized ATF had better thermal performance, lower cladding hoop stress, and could provide more coping time under accident conditions.

• Tribology and Lubricants
• /
• 제37권2호
• /
• pp.48-53
• /
• 2021

Wind energy is considered as the most competitive energy source in terms of power generation cost and efficiency. The power train of the pitch drive for a wind turbine uses a 3-stage complex planetary gear system in being developed locally. A gear train of the pitch drive consists of an electric or hydraulic motor and a planetary decelerator, which optimizes the pitch angle of the blade for wind generators in response to the change in wind speed. However, it is prone to many problems, such as excessive repair costs in case of failure. Complex planetary gears are very important parts of a pitch drive system because of strength problem. When gears are designed for the power train of a pitch drive, it is necessary to analyze the fatigue strength of gears. While calculating the specifications of the complex planetary gears along with the bending and compressive stresses of the gears, it is necessary to analyze the fatigue strength of gears to obtain an optimal design of the complex planetary gears in terms of cost and reliability. In this study, the specifications of planetary gears are calculated using a self-developed gear design program. The actual gear bending and compressive stresses of the planetary gear system were analyzed using the Lewes and Hertz equation. Additionally, the calculated specifications of the complex planetary gears were verified by evaluating the results from the Stress - No. of cycles curves of gears.

• 보건행정학회지
• /
• 제29권2호
• /
• pp.160-171
• /
• 2019

Background: This study purposed to compare the difference on medical utilization and health expenditure of baby boomer generation by depression between gender. Methods: Korea Welfare Panel Survey 2016, provided by the Korea Institute for Health and Social Affairs, was used for the analysis. For the research, we used the two-part model, yes or no of use (part 1), and frequency of use (part 2) for medical utilization. The dependent variables are the whether or not to use of hospitalization services, outpatient services, length of stay, outpatient service visits, and health expenditure. And the independent variables are used as the predisposing (education, spouse presence), enabling (insurance type, private insurance, economic activity, income), and need (chronic disease, self-rated health, disability) factors in the Andersen behavior model. Depression was used as intervening variables. Structural equation model and multiple group analysis by gender were used. Results: There were differences in the medical care usage and cost between men and women in baby boomer. For men, mediating effects of depression were present at the hospitalization (yes/no), length of stay, and health expenditure. On the other hand, for women, the mediating effect of depression was found only at the outpatient visits. Specially, depression was working at the medical services by the different way between gender. The size of effect (multiple group analysis) was affected by significant differences between men and women. Conclusion: This study found that the mediating effect of depression is increased medical usage and health expenditure and the effect factors are different by gender. Therefore, it is necessary to establish a medical care policy considering the socio-economic characteristics of baby boomers.

• 해양환경안전학회지
• /
• 제25권2호
• /
• pp.151-158
• /
• 2019

도로 교통에서는 차세대 지능형 교통시스템(C-ITS)의 핵심 기술인 차량용 무선통신기술(WAVE)을 활용하여 교통사고 예방을 위한 차량과 차량, 차량과 인프라간 교통상황 등 정보를 전달하고 있다. 현재 해상에서는 상대선박의 상태 등의 정보를 전달하는 수단으로 AIS를 많이 활용하고 있으나 AIS 과부하 등 문제점이 대두되고 있어 차량용 무선통신기술을 해상에 적용하는 등 이를 해결하기 위한 다양한 연구들이 수행되고 있다. 본 연구에서는 선행연구를 통해 검증된 차량용 무선통신기술(WAVE)의 해상적용을 바탕으로 소형선박에 적합한 선박 충돌경보시스템을 개발하였고 실선 TEST를 통해 충돌경보시스템의 적정성을 검토하였다. 차량용 무선통신기술을 활용한 시스템의 적용을 통해 해양사고 예방뿐만 아니라 e-Navigation이나 자율운항 선박 등 차세대 해양안전기술의 발전에 많은 기여를 할 것으로 예상이 된다.

• The Journal of Asian Finance, Economics and Business
• /
• 제8권1호
• /
• pp.697-710
• /
• 2021

This paper attempts to study the impact of Financial Literacy on Youth Entrepreneurial Intent in Pakistan. A closed-ended self-administered structured questionnaire covering financial literacy, computer knowledge, financial attitude, and financial knowledge with Entrepreneurial Intent was collected from young entrepreneurs. The research tried to investigate the education level with computer skill to inspect the effect of financial literateness on young generation Entrepreneurial Intent in the context of Pakistan. The research model was tested using PLS-SEM and authenticating a measurement model through the advanced methodology and their association with Entrepreneurial Intent. Results revealed that financial literacy and its two parts (financial attitude and financial knowledge) have a positive impact on Entrepreneurial Intent. The size of the joint impact of financial literacy and its components on Entrepreneurial Intent was assessed to be adequate. Entrepreneurial Intent is essential for creating new firms to maintain economic development. Furthermore, it is determined in this research that if youth has better financial knowledge and financial attitude, the probability of Entrepreneurial Intent increases. This suggests that if the youth in Pakistan desire to attain a higher limit of Entrepreneurial Intent, they must implement financial literacy models for enhancing and promoting their current Entrepreneurial Intent.

• 대한금속재료학회지
• /
• 제56권12호
• /
• pp.910-914
• /
• 2018

Since catalyst technology is one of the promising technologies to improve the working performance of next generation energy and electronic devices, many efforts have been made to develop various catalysts with high efficiency at a low cost. However, there are remaining challenges to be resolved in order to use the suggested catalytic materials, such as platinum (Pt), gold (Au), and palladium (Pd), due to their poor cost-effectiveness for device applications. In this study, to overcome these challenges, we suggest a useful method to increase the surface area of a noble metal catalyst material, resulting in a reduction of the total amount of catalyst usage. By employing block copolymer (BCP) self-assembly and nano-transfer printing (n-TP) processes, we successfully fabricated sub-20 nm Pt line and cross-bar patterns. Furthermore, we obtained a highly ordered Pt cross-bar pattern on a Ni thin film and a Pt-embedded Ni thin film, which can be used as hetero hybrid alloy catalyst structure. For a detailed analysis of the hybrid catalytic material, we used scanning electron microscope (SEM), transmission electron microscope (TEM) and energy-dispersive X-ray spectroscopy (EDS), which revealed a well-defined nanoporous Pt nanostructure on the Ni thin film. Based on these results, we expect that the successful hybridization of various catalytic nanostructures can be extended to other material systems and devices in the near future.

• 정보보호학회논문지
• /
• 제22권1호
• /
• pp.155-167
• /
• 2012

클라우드 컴퓨팅 서비스는 이용자 요구에 실시간으로 유연하게 컴퓨팅 자원을 제공하고 사용량만큼 과금하는 고효율의 차세대 IT 서비스이다. 그러나 이용자는 데이터를 '위탁'하고, 인프라, 플랫폼, 어플리케이션 서비스를 '제공'받는 '위탁/제공'의 서비스 구조와 적용기술, 자원공유, 데이터센터 위치 등으로부터 비롯된 많은 위협에 직면해 있다. 클라우드 서비스 도입의 가장 큰 걸림돌로 작용하는 보안과 신뢰성을 담보하기 위해서는 객관적인 평가 기준이 필요하다. 지금까지 정보보호관리체계는 조직의 보안관리 및 IT 운영의 보안 지표로 활용되어 왔다. 그러나 클라우드 컴퓨팅 서비스는 기존의 조직 내 IT 환경과는 다른 관점의 보안관리와 평가기준이 필요하다. 본 논문에서는 클라우드 특성에 맞는 정보보호관리체계를 설계하기 위하여 클라우드 서비스의 핵심요소를 위협관리영역으로부터 도출하고 기본적인 보안관리가 누락되지 않도록 기존 정보보호관리체계의 모든 통제영역을 포함하고 있다. 또 온라인 셀프환경에 따른 서비스 이용을 지원하고 서비스 계약, 제공자 사업현황을 포함하는 서비스 보안관리를 추가하여 설계한다.

• 한국콘텐츠학회논문지
• /
• 제21권3호
• /
• pp.752-760
• /
• 2021

본 연구는 정보통신기술의 발달로 직업으로서의 선호도가 높아지고 있는 유튜브 크리에이터 종사 의향의 예측 요인을 검증하는 데 목적을 두었다. 이를 확인하기 위해 Z세대(20세~24세)의 직업 가치관, 관심과 인식, 자아존중감, 종사 의향 등을 조사하였다. 다중 회귀분석을 실시한 결과, 실재형(-), 예술형(+), 기업형(+)의 직업 가치관이 유의한 영향력을 보였고, 유튜브에 관한 관심도 역시 정적으로 유의한 영향을 미쳤다. 즉, 실재형의 직업적 성격을 가진 사람들일수록 유튜브 크리에이터 종사 의향이 낮은 것으로 나타났으며, 예술형, 기업형 점수가 높은 사람들은 유튜브 크리에이터로 종사할 의향이 높은 것으로 나타났다. 더불어 유튜브에 대한 관심이 높을수록 종사 의향이 높은 것으로 나타났는데, 본 연구는 이러한 결과를 기반으로 직업으로서 유튜브 크리에이터에 대한 진로 지원 서비스 구축의 필요성, 직업 가치관이나 개인의 성향에 따른 차별화된 접근의 필요성 등의 시사점들을 논의하였다. 본 연구는 최근 증가하고 있는 유튜브 크리에이터에 대한 관심도를 반영하여 직업적 관점에서 유튜브 크리에이터에 대한 종사 의향, 그리고 영향요인을 확인하였다는 점에서 의의를 갖는다.

• Journal of Ginseng Research
• /
• 제46권4호
• /
• pp.543-549
• /
• 2022

Background: In physical activity or labor, the human body is in a state of high intensity stress, and all parts or physiological functions of the body respond positively to maintain or balance the need for movement. The human body has many physiological changes in the process of movement, and fatigue is the external manifestation of various complex changes inside the human body. Fatigue is also a physiological mechanism of self-protection after the body reaches a certain level of activity, which can prevent the occurrence of life-threatening excessive functional failure. The generation of fatigue is a very complex process, and its mechanism has not been concluded yet. Therefore, it is an important work to search and screen the effective components of natural plants that have anti-fatigue effect and to explore their mechanism. Methods: This was a 8-week, randomized, double-blind, placebo-controlled clinical trial. A total of 110 subjects who passed physical examination were included according to the scheme design, and randomly divided into a test group which was given KRG and a placebo control group. The calculation is carried out according to the standard of sub-high-intensity exercise test. Results: There was no adverse effect on safety index of subjects after taking red ginseng capsule. After KRG treatment, subjective strength grade is significant lower than placebo treatment. Blood lactic acid content is significantly get lower after trial in KRG group, and significant lower than placebo group. Creatine phosphokinase(CK) content is significantly get lower after trial in KRG group, and significant lower than placebo group. Conclusion: According to the criterion in the test scheme, the result shows that KRG is helpful on relieving physical fatigue.

• 한국콘텐츠학회논문지
• /
• 제22권7호
• /
• pp.253-263
• /
• 2022

본 연구는 베이비부머 세대의 어머니(1955-1963년생)를 둔 에코부머 기혼 여성(1979-1992년생) 382명을 대상으로 사회인구학적 배경변인, 부모-자녀 분화, 결혼안정성, 심리적 복지감 간의 관계를 살펴보았다. 그 결과 친정 어머니와의 월 평균 접촉 빈도가 많을수록 어머니와의 친밀감(연결성)이 높았다. 결혼지속년수가 높을수록 결혼안정성은 낮았고, 교육수준이 높고, 월평균 가구 소득이 높을수록 자기수용성이 높았다. 또한 맞벌이 가정의 여성이 외벌이 가정의 여성에 비해, 친정 어머니로부터 자녀 양육 도움을 받는 기혼 여성이 도움을 받지 않는 여성에 비해 타인과 신뢰할만한 관계를 형성하거나 만족감을 나타내지 못했다. 어머니와 잘 연결되어 있거나 친밀감이 높은 사람은 결혼안정성이 높았고, 결혼안정성이 높은 사람은 심리적 복지감이 높았다. 부모-자녀 분화 수준이 높은 기혼 여성은 자기수용성이 높을 뿐만 아니라, 타인과의 관계 또한 긍정적인 경향이 있었다.