This study compared the use of health functional foods (HFF) by household composition—specifically the presence of minor children—and identified the factors associated with the level of purchase using data from the Food Consumption Behavior Survey 2023 by the Korea Rural Economic Institute. The responses from 3,176 household food purchasers were analyzed, using complex-sample design weights. The primary food purchasers in households with minors (HM) were characterized by a higher proportion of females and purchasers in their 40s–50s, whereas households without minors (HNM) were more often 1–2-person adult households with older purchasers. Both groups reported high rates of home cooking, but HM had a higher shopping frequency. HFF purchases were largely self-initiated rather than gift-driven. The motivations of HFF purchase differed by household type: HM more frequently reported growth/development, learning enhancement, and disease prevention, while HNM emphasized fatigue recovery, health promotion, and disease treatment. The non-use of HFF was most commonly attributed to the lack of perceived needs; information deficits were more salient in HM, whereas cost concerns were stronger in HNM. The average use was 2.2 products per household, with vitamins/minerals, probiotics, omega-3 fatty acids, and ginseng most common. Logistic regression analysis showed that income, interest in health, purchasing method, and product variety were significant predictors of increased HFF spending in HNM, but the explanatory power of the model was not statistically significant in HM. These findings suggest that consumer education and communication strategies regarding HFF should be tailored to the household life cycle and emphasize their safe use, particularly for HM.

본 연구는 제작 직후(1년차) 및 3년 경과 후(4년차) 에 수행한 휨 실험을 통해 철근 콘크리트보와 CFRP 보강근 콘크리트보의 장기 휨 거동을 평가하였다. RC 보는 항복 이후 안정적인 변형을 보이는 전형적인 연성 거동을 나타낸 반면, CFRP 보강근 콘크리트보 는 파괴 시까지 선형 탄성 거동을 보이며 초기 강성은 철근 콘크리트보와 유사하였으나 연성은 제한적으로 나타났다. 실험에서 측정된 휨 내력은 RC 보의 설계 휨강도 51.4 kNm와 CFRP 보강근 콘크리트보의 설계 휨강도 56.9 kNm를 모두 상회하였다. 4년차 RC 보는 유사한 휨 내력과 전반적인 거동을 유지하였다. 반면, CFRP 보강근 콘크리트보는 강성 및 최대 휨 내력이 감소하였으며, 균열 수 감소와 평균 균열 간격 증가가 관찰되었다. 이러한 결과는 시간 경과에 따른 부착 특성의 변화가 CFRP 보강근 콘크리트보의 장기 휨 성능에 영향을 미칠 수 있음을 시사한다.

본 연구는 바이오차 치환율 및 축력 수준에 따른 철근콘크리트(RC) 부재의 휨 거동을 평가하였다. 실험변수는 바이오차 치환 율 0, 5, 10%와 축력 수준 0, 10, 20%이며, 총 9개 실험체를 제작하였다. 실험은 축력을 일정하게 유지한 상태에서 휨 하중을 재하하 여 하중–처짐 관계와 균열 양상, 항복ㆍ최대ㆍ극한 특성값 등을 분석하였다. 실험결과, 축력 증가는 초기 강성 및 항복ㆍ최대 내력을 증가시키는 반면 변형능력과 연성도는 감소하였고, 바이오차 치환율 증가는 초기 강성과 최대 내력을 저하시켜 조기 균열을 유발하는 경향을 보였다.

Fiber laser welding is considered an effective joining process for cryogenic storage structures because of its high welding speed, narrow heat-affected zone, and low thermal deformation. In this study, butt welding was performed on 10 mm-thick SUS316L plates using a fiber laser system, and the distortion behavior according to welding conditions was experimentally evaluated. The main process variables were laser power (4.0 and 4.5 kW) and welding speed (36–54 mm/s), and five welding cases were investigated. Distortion was measured at multiple locations on the welded specimens, and heat input was calculated from laser power and welding speed. The results showed that, under the 4.0 kW condition, distortion increased as welding speed decreased and heat input increased. At a constant welding speed of 48 mm/s, increasing the laser power from 4.0 kW to 4.5 kW caused a slight increase in distortion. Among all conditions, the 4.5 kW-54 mm/s case showed the largest distortion. In addition, identical heat input conditions did not always produce the same distortion level, indicating that welding distortion was affected not only by heat input but also by the combination of laser power and welding speed. These results provide basic data for the prediction and control of welding distortion in fiber laser butt-welded SUS316L for cryogenic hydrogen storage tank applications.

This study assessed the feasibility of deploying mobile safety-sign robots to replace human flaggers in highway work zones and determined the optimal Dynamic Message Display (DMD) configurations. The study consisted of two phases. The first phase involved a pilot test on a test road in Yeoju, where the work zone conditions were replicated by following the highway work zone traffic management guidelines. Eight drivers participated in a pilot test. All four driving behavior indicators demonstrated improvements in driving safety under the robotbased scenario compared with the conventional human flagger scenario. The second phase adopted a Virtual Reality (VR)-integrated Driving Simulator (DS) to analyze the driver behavior across various DMD types. Six robot-based scenarios were designed by combining three DMD message types with two display sizes along with one baseline scenario based on existing guidelines for comparison. Twenty drivers participated in this experiment. A rank-based comparative analysis incorporating five evaluation indicators was performed to derive the optimal DMD display type. Scenario 3 (vertical ‘60’ display) and Scenario 6 (horizontal ‘감속60’ display, ‘Reduce speed to 60’ in English) were identified as the optimal DMD display types. These findings establish a foundation for the development of traffic management standards for safety sign robots in highway work zones.