• International Journal of Naval Architecture and Ocean Engineering
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• 제11권1호
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• pp.396-408
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• 2019

The tubes which are applied in jacket platforms as the supporting structure might be collided by supply vessels. Such kind of impact will lead to plastic deformation on tube members. As a result, the ultimate strength of tubes will decrease compared to that of intact ones. In order to make a decision on whether to repair or replace the members, it is crucial to know the residual strength of the tubes. After being damaged by lateral impact, the simply supported tubes will definitely loss a certain extent of load carrying capacity under uniform axial compression. Therefore, in this paper, the relationship between the residual ultimate strength of the damaged circular tube by collision and the energy dissipation due to lateral impact is investigated. The influences of several parameters, such as the length, diameter and thickness of the tube and the impact energy, on the reduction of ultimate strength are investigated. A series of numerical simulations are performed using nonlinear FEA software LS-DYNA. Based on simulation results, a non-dimensional parameter is introduced to represent the degree of damage of various size of tubes after collision impact. By applying this non-dimensional parameter, a simplified formula has been derived to describe the relationship between axial compressive residual ultimate and lateral impact energy and tube parameters. Finally, by comparing with the allowable compressive stress proposed in API rules (RP2A-WSD A P I, 2000), the critical damage of tube due to collision impact to be repaired is proposed.

• 한국주조공학회지
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• 제38권6호
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• pp.121-131
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• 2018

The effect of additives on the castability of the AC2BS aluminum alloy, which contains 35% recycled scrap, was investigated. For the wide utilization of the recycled scrap AC2BS aluminum alloy, the research results were compared to those with the AC2B virgin alloy, which is typical Al-Si-Cu alloy system. It was confirmed that the addition of Al-5%Ti-1%B increased the ${\alpha}$-Al nucleation temperature during solidification and decreased the grain size through cooling curve and microstructural observations of the recycled alloy. It was also found that an addition of Al-10%Sr decreased the eutectic Si growth temperature during the solidification process and modified the shape of the eutectic Si of the recycled alloy. The characteristics of fluidity, shrinkage and solidification crack strength were evaluated. For the AC2BS aluminum alloy containing 35% recycled scrap, both ${\alpha}$-Al grain refinement due to Ti-B and eutectic Si modifications due to Sr contributed to the improvement of the fluidity. The macro- shrinkage ratio increased with additions of both Al-10%Sr and Al-5%Ti-1%B and the micro-shrinkage ratio increased with the addition of Al-10%Sr but decreased with the addition of Al-5%Ti-1%B. The casting characteristics of TiB and Sr-treated AC2BS aluminum alloy containing 35% recycled scrap are similar to those of AC2B virgin alloy. The improvement of the solidification crack strength of the AC2BS aluminum alloy was possible by the reduction of the grain boundary the stress concentration through the enhancement by both ${\bullet}{\cdot}$-Al refinement and eutectic Si modification. More extensive use of the AC2BS aluminum alloy containing 35% recycled scrap can be expected in the future.

• 대한지역사회영양학회지
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• 제26권4호
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• pp.259-269
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• 2021

Objectives: This study aimed to investigate the changes in the eating habits and lifestyle of middle-aged women in Gwangju during the COVID-19 pandemic. Methods: A total of 428 middle-aged women aged between 40 and 60 participated in a survey relating to general information, food and lifestyle, health functional food, and menopausal symptoms. The correlation between the variables was analyzed. Results: In the positive habits, the intake of nutritional supplements for immunity enhancement increased the most, followed by the use of media to learn healthy eating tips, and diets including healthy food. Negative habits increased in the order of frequency of taking delivery orders, levels of stress or anxiety, and time spent sitting or watching movies. In the case of recommended foods, the intake increased the most in the order of eggs, fruits, vegetables, milk/dairy products, and seaweed. Non-recommended foods increased in the order of meat, bread, rice, and noodles. The awareness of health functional foods was in the increasing order of interest, knowledge, consumption experience, and purchase amount. The type of health functional food intake was in the increasing order of probiotics, multivitamin and mineral supplements, vitamin C, collagen, and omega-3. Menopausal symptoms were in the increasing order of bone and joint pain, poor sleep quality, emotional ups and downs, loneliness, and feeling of emptiness. In the correlation of major variables, positive habits showed a significant positive correlation with recommended food intake and the recognition of health functional foods. Negative habits showed a significant positive correlation with non-recommended food intake and a significant positive correlation with menopausal symptoms. Recommended food intake showed a significant positive correlation with health functional food recognition and intake and menopausal symptoms. Conclusions: This study suggests that it is necessary to establish social measures to reduce the negative effects of the COVID-19 pandemic on middle-aged women and to ensure effective self-management through a healthy lifestyle since the pandemic has a long-term impact.

• 한국지반공학회논문집
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• 제36권12호
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• pp.69-76
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• 2020

Back-to-Back 보강토옹벽은 좁은 구간에 양립하는 옹벽의 형식을 가지기 때문에 벽체간의 이격거리에 따라 보강재가 겹치게 되어 보강재 간의 상호작용에 의한 응력 변화와 일체화된 상태에서 전체가 거동하는 문제 등으로 설계단계에서 신중한 접근이 필요하나 현재 국내에 정형화된 설계기준이나 지침이 전무한 상태이다. 본 연구는 이러한 Back-to-Back 보강토옹벽에 대해 옹벽폭 대 높이비(옹벽폭비, Wb/H)에 따른 최적 보강길이비에 대해 고찰하였다. 옹벽폭비는 FHWA 설계기준의 Case II에 해당하는 1.1H, 1.4H, 1.7H, 2.0H, 높이는 일반적으로 가장 많이 적용되고 있는 3.0m, 5.0m, 7.0m, 10.0m를 대상으로 하였으며, 각 조건에서 수치해석을 통해 FHWA 설계기준의 적정성과 옹벽의 높이 및 옹벽폭비에 따른 최적 보강길이비를 제안하였다.

• 한국산업보건학회지
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• 제30권4호
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• pp.364-375
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• 2020

Objectives: The purpose of this study is to suggest a direction for consumer-oriented curriculum development by analyzing the priorities of subjects and their preference for educational methods. Methods: The participants included 773 management supervisors and education practitioners in the workplace, and a survey was conducted from April 17 to August 30, 2019. Frequency analysis, t-test, Borich's Needs Analysis, and Locus for Focus Model analysis were performed using Microsoft Excel 2019 and IBM SPSS 21.0. Results: The highest perceived priorities for education subjects were as follows: ① 'CPR and First Aid Practice' and 'Occupational Disaster Prevention and First Aid Basics' in the manufacturing industry; and ② 'Emotional Labor and Job Stress Prevention', 'Occupational Disaster Prevention and First Aid basics, and 'Musculoskeletal Disorder Prevention' in the service industry. 'Collective education' was the most preferred method of education. 'School-type' was preferred for the seating arrangement, and the proper number of trainees was considered to be about 30. Respondents said the contents of the education was a top priority when they applied for education, and curriculum and appropriate textbooks should be considered in calculating the cost of education. Conclusions: Practical subjects and subjects related to major hazards by industry were required for management supervisor education. It was proposed in this study that the contents and operating methods of education be changed so that workers can easily comprehend essential subjects such as the Occupational Safety and Health Act. In conclusion, it is necessary to design the curriculum and apply educational methods suitable for each subject's characteristics in consideration of the priorities for subjects reflected in the needs of trainees.

• 디지털융복합연구
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• 제18권12호
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• pp.105-115
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• 2020

본 연구는 클라우드 컴퓨팅 서비스의 혁신저항에 영향을 주는 요인을 알아보고, 국내 클라우드 컴퓨팅 서비스 사용을 높이기 위한 정책적 대안을 제시하는데 목적이 있다. 이를 위해 정부지원을 받아 클라우드 컴퓨팅 서비스를 도입한 중소기업 178개사를 설문조사하였다. 그 결과, 테크노스트레스, CEO 정보화 리더십과 조직구조 집권성은 혁신저항에 유의미한 영향을 미쳤다. 따라서 향후에는 첫째, 테크노스트레스를 줄일 수 있는 방향으로 이용자 중심의 클라우드 컴퓨팅 서비스 제공이 필요하다. 둘째, 중소기업별 조직특성에 대한 보다 심도 있는 이해를 통한 클라우드 컴퓨팅 서비스의 적용이 필요하다. 셋째, 보안인증 고도화 및 보상제도가 필요하다. 클라우드 컴퓨팅 서비스 이용을 촉진하기 위해서는 이용자가 안전하게 이용할 수 있는 환경이 우선적으로 마련되어야 할 것이다.

• 한국표면공학회지
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• 제54권3호
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• pp.102-111
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• 2021

The corrosion behaviors of laser-welded super duplex stainless steel tubes with post-weld heat treatment(PWHT) conditions(950, 1000, 1050, 1100 ℃ for 5 and 30 min) were evaluated by electrochemical potentiodynamic polarization and critical pitting temperature measurements. This study showed that the critical metallurgical factors affecting the degradation of corrosion resistance of a steel tube in as-welded condition were the unbalanced phase fraction(ferrite:austenite = 94:4), Cr₂N precipitation, and phase transformation from the austenite phase to ɛ-martensite(via stress-induced phase transformation). The improvement in the corrosion resistance of the welded specimen depends greatly on the PWHT conditions. The specimens after PWHT conducted below 1000 ℃ showed inferior corrosion resistance, caused by precipitation of the sigma phase enriched with Cr and Mo. At 1100 ℃ for a longer duration in PWHT, the ferrite phase grows, and its fraction increases, leading to an unbalanced phase fraction in the microstructure. As a result, pitting can be initiated primarily at the interface between the ferrite/austenite phase, particularly in base metal.

• 한국콘텐츠학회논문지
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• 제21권3호
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• pp.282-300
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• 2021

본 연구의 목적은 코로나19 확산으로 가족생활에서 급격한 변화가 일어난 1차 확산기에 블로그와 온라인 카페에 게시된 소셜 빅데이터를 분석하여 키워드를 파악하고, 게시글에 잠재된 주요 토픽을 발견하는 것이다. 강화된 사회적 거리두기가 처음 시행되었던 2020년 2월 23일부터 4월 19일까지 네이버와 다음의 블로그 및 카페에 게시된 글 중 '코로나'와 '가족' 또는 '코로나'와 '가정'이 함께 언급된 문서 총 351,734건을 분석하였다. 수집된 데이터는 전처리를 거쳐 텍스트 마이닝 기법으로 분석하였다. TF-IDF 가중치 값을 바탕으로 상위 100개 단어를 살펴보았으며, 잠재디리클레할당 방식의 토픽모델 분석을 통해 총 22개 토픽을 도출하고 토픽명을 부여하였다. 연구결과, 코로나19가 가족의 일상생활에 미친 전방위적 영향이 나타났으며, 특히 식생활, 주거생활, 여가생활, 종교생활, 자녀돌봄, 자녀교육, 가족관계, 가족의례 등에서 변화가 두드러졌다. 더불어, 가족 관련 국내 문헌에서는 잘 논의되지 않던 건강공동체로서의 가족을 시사하는 토픽도 등장하였다.

• Journal of Dental Anesthesia and Pain Medicine
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• 제21권2호
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• pp.155-165
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• 2021

Background: This study aimed to assess the course of anxiety and pain during lower third molar (LTMo) surgery and explore the role of mobile and single-channel electroencephalography under clinical and surgical conditions. Methods: The State-Trait Anxiety Inventory (STAI), Corah's Dental Anxiety Scale (DAS), and Interval Scale of Anxiety Response (ISAR) were used. The patient self-rated anxiety (PSA), the pain felt during and after surgery, EEG, heart rate (HR), and blood pressure (BP) were assessed. Results: The Attention (ATT) and Meditation (MED) algorithms and indicators evaluated in this study showed several associations. ATT showed interactions and an association with STAI-S, pain during surgery, PSA level, HR, and surgical duration. MED showed an interaction and association with DAS, STAI-S, and pain due to anesthesia. Preclinical anxiety parameters may influence clinical perceptions and biological parameters during LTMo surgeries. High STAI-Trait and PSA scores were associated with postoperative pain, whereas high STAI-State scores were associated with more pain during anesthesia and surgery, as well as DAS, which was also associated with patient interference during surgery due to anxiety. Conclusions: The findings suggest that single-channel EEG is promising for evaluating brain responses associated with systemic reactions related to anxiety, surgical stress, and pain during oral surgery.

• 문화기술의 융합
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• 제8권4호
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• pp.289-296
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• 2022

이 연구의 목적은 S 대학교 교양필수과목 중 하나인 교양과 인성 수업에 나타난 학생들의 반응과 자기 이해를 살펴보는데 목적을 두었다. 연구 결과는 다음과 같다. 첫째, 이 수업에서 학생들의 긍정적인 변화에 미친 영향 정도는 5단계 리커트 척도를 사용하여 보통 이상의 높은 단계의 반응이 나타났다. 특히 연구자가 실시한 영화 토의 결과 만족도는 매우 높게 나타났다. 둘째, 그림 검사 분석 결과 스트레스와 자원 척도를 통한 대처 능력의 변화가 학생들에게 나타났으며, 학생들은 자신의 마음을 들여다봄으로써 자신을 이해할 수 있는 기회가 되었다. 본 연구는 문학과 예술, 그리고 영상 등을 통해 학생들의 인성을 함양하고 토의를 통해 책임감, 리더십, 협동심, 배려, 소통, 공감 등 세계 시민으로서의 자질을 함양할 수 있는 수업 예시를 제시하였다.