This study investigated the hydrogen embrittlement behavior of 316 austenitic stainless steel subjected to hydrogen charging at different temperatures, using slow strain-rate testing and acoustic emission (AE) techniques. Compared to the noncharged specimen, the specimen H-charged at 25 °C exhibited similar elongation and a ductile fracture mode, while hydrogen charging at 60 °C led to a pronounced reduction in elongation accompanied by quasi-cleavage fracture. This degradation may be associated with enhanced hydrogen transport and redistribution at the elevated charging temperature, which could increase the effective hydrogen activity at microstructural sites, known to be critical to crack initiation and propagation. Feritscope measurements indicated a relative increase in strain-induced martensite formation in the hydrogen-charged specimens. Specifically, the H-charged at 25 °C specimen showed a localized increase in martensite near the fracture surface, and the H-charged at 60 °C specimen exhibited a high martensite fraction over the measured region of the gauge section. AE analysis showed that the cumulative number of AE events decreased after hydrogen charging, while the cumulative absolute energy increased, particularly for the H-charged at 60 °C specimen. These results suggest a relative change in fracture behavior under hydrogen-charged conditions, from ductile fracture involving numerous low-energy AE events to more abrupt fracture behavior characterized by fewer but more energetic AE events. This study suggests that AE analysis can serve as a complementary tool for characterizing deformation and the fracture behavior associated with hydrogen embrittlement in austenitic stainless steels.

This study examined the association between the food choice behavior and blood pressure among hypertensive adults aged 50 years or older and identified subgroup differences by individual characteristics. Data were obtained from the 2019-2020 Korea National Health and Nutrition Examination Survey. A total of 1,954 hypertensive adults aged 50 years or older were included. The food choice behavior was assessed using nutrition label use in food choice and dietary restriction. Differences in the systolic and diastolic blood pressure were examined using descriptive statistics, univariate analyses, and decision tree analysis. The proportion of nutrition label use in food choice was higher in females than in males. Among the non-smokers aged under 68 years, the systolic blood pressure was significantly lower in the nutrition label use group (p<0.05). Among the participants aged 79 years or older, the diastolic blood pressure was significantly lower in the dietary restriction group (p<0.05). Decision tree analysis showed that the association between food choice behavior and blood pressure differed according to age and smoking status. These findings highlight the need for subgroup-specific nutrition education strategies to support blood pressure management in older hypertensive patients.

일반적인 도로교와 달리 방조제 배수갑문 교량은 대규모 질량의 수문이 교각에 직접 일체화된 고도의 비정형 복합 구조물로, 집중적인 지진 손상에 매우 취약하다. 충돌과 같은 복잡한 동적 상호작용을 정확하게 평가하기 위해, 본 연구는 ABAQUS를 활용하여 배수갑문 교량에 대한 3차원 비선형 시간이력해석(NLTHA)을 수행하였다. 구조물의 비선형 극한 거동을 구현하기 위해 콘크리트 손상 -소성 모델과 포트 받침의 접촉 비선형성을 모사하는 커넥터 요소가 적용되었다. 해석에는 세 가지 실측 지진파를 바탕으로 최대지반 가속도로 스케일링된 총 36개의 지진 하중 조건이 사용되었다. 해석 결과, 지진 작용 방향에 따라 뚜렷하게 다른 파괴 메커니즘이 규명되었다. 교축 방향 지진 작용 시에는 교대와 갑문 간의 비선형 충돌이 발생하여 교각에 손상이 발생하였다. 반면 교직 방향 지진 시에는 고중량의 갑문이 수동적 감쇠기 역할을 수행하여 지진 에너지를 흡수하고 교각의 전체적인 붕괴를 방지하였다. 그러나 소산되 지 못한 잉여 지진 에너지가 거더 하부로 재분배되면서 응답 스펙트럼 증폭비(AF)의 증가 및 인장 균열 및 주철근 항복과 같은 손상이 유발되는 것을 확인하였다.

Hydrogen embrittlement (HE) remains one of the most critical challenges in ensuring the structural integrity of steels for hydrogen energy infrastructures, including storage and transport systems. Despite decades of research, the underlying mechanism of HE is still not fully understood due to the complexity of hydrogen-microstructure interactions across multiple length scales. Cryogenic Atom Probe Tomography (Cryo-APT) has recently emerged as a unique method of providing near-atomic resolution and compositional sensitivity for hydrogen analysis, thereby enabling direct visualization of hydrogen distribution at defects, interfaces, and precipitates. This review summarizes recent progress in Cryo-APT-based investigations of hydrogen behavior in steels, with a focus on trapping mechanisms, the role of microstructural features, and the synergistic activation of multiple HE mechanisms. Key technical developments, such as cryogenic workflows and isotope tracing, have significantly advanced the reliability of Cryo-APT hydrogen quantification. Case studies on ferritic-martensitic steels, pearlitic steels, and advanced high-strength steels highlight the potential of Cryo-APT to reveal both diffusible and non-diffusible hydrogen trapping. While current limitations include local sampling bias, experimental complexity, and signal interpretation challenges, continuous improvements in methodology and integration with multiscale modeling are expected to establish Cryo-APT as a core approach for elucidating HE mechanisms. This review provides a comprehensive perspective on the current technical state and future directions of Cryo-APT in HE researches.

This study analyzed online food consumption behaviors by segmenting consumers based on their dietary lifestyles using the Consumer Behavior Survey for Food in 2024 of the Korea Rural Economic Institute. Factor analysis and cluster analysis classfied the dietary lifestyles of the respondents into the ‘convenience and experience-seeking group’, ‘low involvement group’, ‘health-seeking group’, and ‘plan-seeking group’. The highest frequency of online food purchases by respondents was ‘once every two weeks’, and the most common reason for purchasing food online was ‘because it is delivered’. The most frequently used channel for online food purchase was ‘online shopping malls’, with price, quality, and overall satisfaction remaining above average. The analysis of perceptions and behavioral patterns revealed that consumers primarily utilized online food services for their convenience and place significant importance on others’ experiences and verified brands. Among the dietary lifestyle groups, the ‘convenience and experience-seeking group’ showed the highest mean scores across most perceptions and behavioral items. These results confirm that online food consumption varied significantly depending on dietary lifestyle groups, highlighting that dietary lifestyle is a crucial factor for market segmentation and the development of targeted marketing strategies.

본 연구는 무용을 기반으로 한 연극과 사진을 활용한 문화예술교육 프 로그램 참여가 성인 발달장애인의 자율성, 자기표현, 사회적 행동에 미치 는 효과를 분석하였다. 이를 위해 G시 인재평생교육진흥원과 A대학교가 협업하여 진행한 장애인 문화예술교육 특화 프로그램에 참여한 성인 발달 장애인 10명을 대상으로 연구를 진행하였다. 연구방법은 양적연구와 수업 관찰 및 면담조사 등의 질적 연구를 병행한 혼합분석방법을 활용하였다. 연구결과, 무용 기반 연극과 사진을 활용한 문화예술 프로그램이 성인 발달장애인의 자율성, 자기표현, 사회적 행동에 긍정적인 효과가 있음을 확인하였다. 구체적인 내용을 살펴보면 첫째, ‘참여 정도’, ‘적극적인 표 현과 반응’, ‘창작 활동의 적극성’이 긍정적으로 변화하며 스스로 결정하 고 행동하는 자율성이 향상되는 모습을 확인하였다. 둘째, ‘표현 거부’와 ‘소극적인 표현’에서 점차 ‘적극적인 표현’, ‘망설임 없는 표현’, ‘자유로운 표 현’ 으로 변화되는 모습을 통해 자기표현이 향상됨을 확인하였다. 셋째, 상대방 행동에 ‘적극적인 반응’과 ‘경청’하는 태도를 보였고, ‘적극적인 팀 활동’, ‘협동 심’, ‘양보’, ‘배려’, ‘자신의 감정 통제’ 등이 긍정적으로 변화하는 모습을 확인하였다. 본 연구의 결과를 기반으로 장애인의 자율성, 자기표현, 사 회적 행동 촉진을 위한 문화예술교육의 방향을 시사점으로 제안하였다.

This study examined the intake status and the factors affecting intake of functional foods using the data from Consumer Behavior Survey for Food by the Korea Rural Economic Institute. Among the total respondents, 80.4% took functional foods, and the number of respondents who took two types of functional foods was the highest. The main reason for taking functional foods was to prevent disease, and the main places of purchase of functional foods were off-line large supermarkets, on-line shopping malls, and pharmacies. Compared to a year ago, the percentage of increase in functional food purchases this year was higher than the percentage of decrease. The most common reasons for not taking functional foods were ‘not feeling the need’ and ‘not trusting the quality’. As a result of conducting a complex samples logistic regression analysis to identify the factors affecting the intake of functional foods, gender, age, marital status, illness state, alcohol drinking, and convenience-seeking type among dietary lifestyles were significant.

This study aimed to compare food procurement and dietary behavior of single-person households in Korea. A total of 949 single-person households that participated in the 2022 Food Consumption Behavior Survey were divided into three age groups: 20~39 years (n=204), 40~59 years (n=317), and 60~74 years (n=428). Monthly expenditure on eating out was similar for the 20~39 and 40~59 age groups at around 145,000 KRW, while the 60~74 age group spent 79,823 KRW (p<0.001). The frequency of eating out was the highest at 2~3 days per week for the 20~39 age group, with take-out occurring 1 day per week (p<0.01). Regarding online food purchases, 35% of the 20~39 age group bought food online once every two weeks, whereas 40~59 and 60~74 age groups had higher percentages of those buying non-online food (44.7% and 89.0%, respectively, p<0.001). Regarding dietary competency index, healthy eating scores were the highest in the 60~74 age group (p<0.01). As the dietary competency index increased, monthly expenditure on take-out decreased for the 40~59 age group while satisfaction with current diet increased across all age groups (p<0.01). This study is expected to be helpful for developing nutrition education materials tailored to different life stages.

This study compared the dietary perceptions, food labeling behaviors, and purchasing patterns of vegetarians and nonvegetarians. The data from 5,811 adults aged ≥19 years who participated in the 2023 Consumer Behavior Survey for Food were analyzed. The participants were divided into vegetarians and non-vegetarians according to their dietary practices. Vegetarians were further divided into strict, semi, and occasional vegetarians. Non-vegetarians regularly consumed plantand animal-based foods without dietary restrictions. Vegetarians comprised 15.4% of the participants, and health (50.4%) was the primary motivation for adopting a vegetarian lifestyle. Compared to non-vegetarians, vegetarians prioritized their rights and responsibilities as citizens and identified a vegetable-centered diet as the most crucial factor for health. Vegetarians showed greater interest and trust in food labeling than non-vegetarians. Vegetarians selected a wider variety of food and had different purchasing motivations when purchasing eco-friendly foods than non-vegetarians. Vegetarians exhibited higher purchase frequencies across all categories than non-vegetarians and had different reasons for purchasing convenience foods. These findings highlight the diversity of vegetarian dietary motivations and behaviors, emphasizing the need for tailored dietary policies and education.

Background: The increasing demand for real-time professional fitness coaching has led to a need for accurate exercise posture recognition using artificial intelligence. Objectives: To compare the performance of Feedforward Neural Network (FNN) and Stacked Long Short-Term Memory (LSTM) models in classifying fitness posture images using detailed joint coordinate labeling. Design: Comparative analysis of machine learning models using a labeled dataset of fitness posture images. Methods: A dataset from AI-hub containing images and data of 41 exercises was used. Five exercises were selected and processed using a custom program. Data was converted from JSON to CSV format, augmented with joint condition information, and analyzed using Google Colab. Results: The best FNN model achieved a training error of 1.21% and test error of 9.08%. The Stacked LSTM model demonstrated superior performance with a training error of 1.05% and test error of 6.09%. Conclusion: Both FNN and Stacked LSTM models effectively classified sequential fitness images, with Stacked LSTM showing superior performance. This indicates the potential of Stacked LSTM models for accurate fitness posture classification in real-time coaching scenarios.

본 논문에서는 초기 압축 성형 공정 조건들이 단섬유 강화 복합소재 구조물의 기계적 거동 특성에 미치는 영향을 효과적으로 반영 할 수 있는 압축 성형-구조 연계 해석 방안을 제안하였다. 압축 성형 해석을 바탕으로 초기 charge의 형상 및 배치에 따른 부위별 단섬 유 배향 특성을 분석하였으며, 평균장 균질화 이론을 통해 단섬유 배향 특성에 따른 등가 이방 물성을 도출하였다. 나아가, 단섬유 배 향 정보가 Mapping된 유한요소 모델을 기반으로 초기 공정 조건들에 의해 야기되는 부위별 거동 특성 변화를 고려할 수 있는 압축 성 형-구조 연계 해석을 진행하였다. 관련 수치 예제 검증을 통해 제시된 해석 방안은 압축 성형을 통해 제작된 단섬유 강화 복합소재 구 조물 설계 과정에서 효과적인 솔루션을 제공함을 확인하였다.

본 논문에서는 3D 프린팅 공정을 통해 제작된 단섬유 강화 복합소재 구조물의 기계적 거동을 효과적으로 예측하기 위한 AM 공정 연계 구조 해석 기법을 제안하였다. 복합소재 3D 프린터(Mark Two, Markforged)를 활용하여 다양한 노즐 경로를 갖는 인장 시편을 출력하였으며, 출력물에 대한 인장 시험을 진행하였다. 또한, 노즐 경로에 따른 부위별 이방 물성을 도출하기 위해 실험적 데이터를 기반으로 역공학 기법을 적용하였다. 제안된 AM 공정 연계 구조 해석 방안의 타당성을 검증하기 위해 실험 결과와의 비교/분석을 병 행하였으며, 부위별 이방 물성이 반영된 FE 모델을 바탕으로 AM 공정 연계 구조 해석을 수행함으로써 복합소재 3D 프린팅 출력물의 거동 양상을 정확하게 예측할 수 있음을 확인하였다.

서울시의 대표적인 대중교통 수단인 도시철도를 이용하는 승객 수는 지속적으로 증가하고 있다. 이에 따라 출 퇴근시간대에 열차 내의 혼잡뿐만 아니라 역사내의 혼잡까지 이어져 안전사고가 발생하기도 한다. 본 연구는 역사에서 발생되는 보행흐름의 위험 여부를 판단하기 위해 도로의 교통류에서 활용되고 있는 vehicle accumulation과 travel time 간의 elliptic bivarate relationship을 적용하였다. 또한 보행흐름과 교통류의 혼잡발생 과정을 비교하여 차이점을 규명하였다. 본 연구에서는 도시철도 역사내 CCTV영상을 기반으로 실제 데 이터를 추출하여 역사내 통로에 발생하는 여러 보행흐름을 혼잡강도와 혼잡지속도에 따라 분류하여 비교분석하였다. 혼잡이 발생하는 여러 역의 첨두, 비첨두, 주말등 다양한 시간대의 CCTV 영상을 확보하였고, ByteTrack 방식을 활용하여 객체를 검지하였다. 검지된 보 행흐름을 강도, 지속도에 따라 분류하고 보행 누적량과 평균통행시간을 산출하여 비교분석하였다. 또한, elliptic bivarate relationship의 형태가 교통류와는 어떠한 차이점이 있는지를 규명하고 보행에서의 위험 상황 여부를 그래프를 통해 확인하였다. 분석 결과, 혼잡발생 강도가 높을수록 그래프 타원의 장축이 길게 나타났고, 보도유효폭이 클수록 타원의 기울기가 낮게 나타났다. 또한, 사람들의 평균보 행속도가 클수록 타원이 낮게 위치하였다. 마지막으로 흐름이 바로 해소되지 않고 지속되는 보행흐름의 경우, 일반적인 타원형태에서 우측부분에 타원이 추가로 형성됨을 확인하였다. 교통류와 비교한 결과, 차량의 경우 교통량에 따라 속도가 일정하게 나타나지만, 보 행의 경우 보행량과 속도의 관계가 비교적 불분명하였다.

The domestic swine industry is currently facing a threat due to the recent increase in pork imports. This study aims to determine what factors influence consumers' intention to consume imported pork and suggest measures to support the domestic pork industry. To achieve this, we analyzed data from the Korea Rural Economic Institute's Food Consumption Behavior Survey using a binary logistic regression model. The results revealed that a higher intention to consume imported pork is linked to a higher intention to consume imported rice, purchasing meat online, frequent purchases of HMR, and procuring U.S. beef, especially among urban residents. On the other hand, a lower intention to consume imported pork is associated with a higher awareness of animal welfare certification, frequently dining out, and older age. Based on these findings, we propose the following response measures for the domestic swine industry: implementing educational programs, marketing, and advertising specifically targeting urban residents to improve their perception of domestic agricultural products; enhancing price competitiveness through distribution optimization; and developing policies to promote the use of domestic pork as an ingredient in processed foods.