This study was conducted to compare and analyze the crop-livestock circulation indicators, manure compost circulation, nutrient circulation, and carbon footprint of organic and conventional dairy farms. The survey farms were 13 organically certified dairy farms and 12 conventional dairy farms. A field survey was conducted in 2024. The forage crop cultivation area per head (LSU) of organic dairy farms was 1,539.8 ㎡, which was 2.3 times more than the 682.9 ㎡ of conventional dairy farms. The livestock density index, which indicates the number of cattle per acre of farmland, was lower in organic dairy farms (6.4 LSU/ha) than in conventional dairy farms (9.3 LSU/ha). The self-produced feed feeding rate of organic dairy farms was 31.9%, which was 12.6% higher than 19.3% in conventional dairy farms. The domestically purchased feed feeding rate was 11.6% in organic certified farms (11.6% lower than 22.5%). The imported concentrate feed feeding rate was 33.2% in organic certified farms and 37.5% in conventional dairy farms, which showed no significant difference. The area of forage crops in organic dairy farms was 0.15 ha/head, which was higher than 0.11 ha/head in conventional farms. The annual milk production of organic dairy farms was 10,101 kg, which did not show a significant difference from conventional farms. The local circulation and Off-farm transfer rates of compost in organic certified farms were 5.1% and 0.4%, respectively, which were lower than those in conventional farms. The annual surplus nitrogen per cow (LSU) was 92.1 kg in organic dairy cow certified farms, which was 20% lower than 115.4 kg in conventional farms. The carbon footprint per kg of milk was 1.16 kgCO2eq in organic certified farms, which was 28% lower than 1.61 kg CO2eq in conventional farms.

This study develops a scientific fishing-ground exploration framework for the Korean large purse-seine fishery, where traditional experience-based searching has become increasingly unreliable under rapid climate variability. AIS-derived fishing locations from 2021 to 2023 were integrated with HYCOM-based temperature and salinity fields and MODIS-Aqua chlorophyll-a data to construct a unified environmental – fishing dataset. After multicollinearity screening and principal component analysis, temperature and salinity at 30 m depth and chlorophyll-a were selected as representative predictors. Using these variables, a generalized additive model (GAM) with background-sampled pseudo-absence data and monthly maximum entropy (MaxEnt) models were developed to quantify nonlinear habitat – environment relationships and predict monthly and seasonal mackerel fishing occurrences. Model performance was evaluated using independent data from 2024. GAM exhibited relatively stable predictive performance across months with generally high AUC and TSS values whereas MaxEnt showed pronounced seasonal variability and was effective in identifying potential habitat structures based on presence-only environmental conditions. Spatial predictions from both models showed good agreement with observed fishing-ground distributions during specific seasons, reproducing high-suitability zones associated with seasonal thermal – salinity fronts and productivity gradients. These results provide insights into the environmental mechanisms governing purse-seine fishing grounds and demonstrate the complementary roles of GAM for operational prediction and MaxEnt for potential habitat exploration.

본 증례는 1형 자가면역췌장염 병력이 있는 남성 환자에서 동반된 분지형 췌관내유두상점액종양으로 장기간의 추적관찰 중 영상 검사에서 췌장 낭종의 고위험 소견이 새롭게 발생하여 수술을 시행하였고, 최종 병리검사에서 분지형 췌관내 유두상점액종양의 악성 변화가 아닌 자가면역췌장염 재발이 확인된 드문 사례이다. 본 증례는 췌장 낭종의 추적관찰 중 새로운 영상 변화가 관찰될 경우, 악성화뿐 아니라 기저 질환의 재발 또는 공존 가능성까지 포괄적으로 고려해야 함을 시사 한다.

This study experimentally evaluated the filter lifespan extension achieved by a retractable, built-in air purification system equipped with a self-cleaning rotating filter. Conventional fixed-type air purifiers commonly experience a rapid increase in pressure drop and non-uniform airflow distribution as dust accumulates on the filter surface, leading to degradation in long-term purification performance. To overcome these limitations, the proposed system incorporates a retractable filter module and a rotational dust-removal mechanism designed to maintain stable airflow and reduce particulate loading during extended operation. Experiments were carried out in a controlled 30 m3 residential-scale test chamber to compare filtration performance, pressure-drop characteristics, and particle removal efficiency between the self-cleaning retractable system and a conventional fixed-depth configuration. The results indicate that the rotating self-cleaning mode reduced pressure drop by up to 18.5% and improved PM2.5 removal efficiency by approximately 12.7% relative to fixed operation. Increasing the filter protrusion depth further enhanced airflow uniformity and expanded the clean-air coverage area, thereby delaying the onset of filter saturation. Overall, the findings demonstrate that the proposed retractable, built-in air purification system effectively suppresses pressure-drop rise, maintains purification efficiency, and extends usable filter life. These results confirm the system’s practical applicability for residential indoor-air-quality management and lay the foundation for future optimization and commercialization.

Integrated crop–livestock farming systems improve the self-sufficient feed ratio, and provide environmental benefits for agro-ecosystems. This study was conducted to evaluate the crop-livestock recycling indicators of Korean Hanwoo farms. 55 Korean beef farms were classified into five types. Organic Hanwoo farms were insufficient the area of forage crop cultivation required for Hanwoo certification in Korea, with forage crop sufficiency index of 49.6%. The forage self sufficiency index of grazing eco-farms was 108.5%, and self-certified (PGS) and conventional livestock farms was only 24.5 and 25.6%, respectively. The forage self sufficiency index was 60.4, 52.9, and 111.9% for Hanwoo + grassland crop, Hanwoo + forage crop + rice, and Hanwoo + grassland combined farms, respectively. Livestock density was 10.3 LSU (livestock units)/ha for organic Korean cattle farms, which was lower than 25.6 LSU/ha for conventional farms. In addition, the livestock density of grassland eco-farms was the lowest at 3.4 LSU/ha. Livestock density was 12.2 LSU/ha in the southern region, which was lower than in the central-northern region. In conclusion, forage crop sufficiency and livestock density are considered valid indicators for assessing the level of crop-livestock integrated agriculture.

본 연구에서는 용융염 원자로(MSR)의 열 전달 성능을 최적화하기 위한 수학적 모델을 제안하였다. MSRE 설계 개념을 기반 으로 한 제시된 모델을 통해 차폐 구조물에서의 열 손실을 계산하고, 다양한 변수들이 표면 온도 및 전체 열 성능에 미치는 영향을 평가하였다. SPROULE WR-1200과 같은 칼슘 실리케이트 기반의 단열재를 사용하였으며, 스틸볼 영역은 스틸볼과 물이 채워져 있고, 단열재와 스틸볼 영역 간격(Gap)이 있다고 가정하였다. 분석 결과, 단열재 두께, 간격 크기, 스틸볼 영역의 두께와 같은 변수들이 열 손실 및 표면 온도에 영향을 미친다는 점을 확인할 수 있었다. 특히, 단열재 두께 최적화를 통해 차폐 구조물의 열 효율성과 안전성을 크게 향상시킬 수 있음을 보여주었다. 본 연구는 차세대 원자로 시스템의 개발을 위한 차폐 구조물의 개념설계에 필요한 기초 자료를 제공한다.

본 연구는 온실 구조에서 서까래–도리 접합부의 반강 접(semi-rigid) 거동을 실험적으로 규명하고, 해석 모델 (GHModeler)의 적용 타당성을 검증하기 위하여 수행되었다. 시중에서 사용되는 선형 죔쇠를 이용하여 교차부 실험체를 제 작하고, 6 자유도 변형 모드에 대한 강성 계수와 항복 특성을 평가하였다. 서까래가 도리 축을 따라 미끄러질 때 강성 계수 243,228.92 N·m-1, 항복 하중 164 N으로 가장 크게 나타났으 며, 도리가 서까래 축을 따라 미끄러질 때는 각각 30,426.78 N·m-1, 118 N으로 현저히 낮은 값을 보였다. 회전 및 비틀림 모드에서도 뚜렷한 차이를 확인하였다. 이어서 실물 규모의 단동 온실을 대상으로 횡하중 재하 시험을 실시하고, 변위 및 응력 거동을 GHModeler 해석 결과와 비교·분석하였다. 비교 결과, 수평 변위(DH2)에서 강접합 모델은 최대 310.2% 오차 를 보인 반면, 인터페이스 요소 모델은 －13.7%~34.1% 범위 로 감소하였다. 응력(S1)에서도 강접합 모델은 최대 84.6%의 오차를 보였으나, 인터페이스 요소 모델은 －9.1%~3.2%로 실험치에 근접하였다. 본 연구 결과는 온실 구조물의 접합부 모델링 및 구조 안전성 평가의 신뢰성을 향상시키는 데 기여할 수 있을 것으로 기대된다.

대부분의 원전 설비의 내진 해석에는 해석이 비교적 간편하고, 설계에 보수성을 적절히 반영할 수 있어 대부분 기기가 설치된 위치에서의 층응답스펙트럼 혹은 In-structure response spectrum을 이용한 응답스펙트럼 해석을 주로 이용하고 있다. 설비 공급자 는 설계 시방서에 층응답스펙트럼 선도의 형태로 입력 지진파 자료를 받게 되는데, 필요시 이를 바탕으로 인공 지진파을 만들어 해석 혹은 시험을 수행한다. 설계지반응답스펙트럼의 경우 RG 1.60에 주어지고 SRP 3.7.1의 요건에 따라 인공 지진파 시간 이력을 생성하 나, 층응답스펙트럼의 경우 명확은 기준이 없어 이를 따르고 있다. 층응답스펙트럼은 구조물의 동특성이 반영되기 때문에 지반응답스 펙트럼에 비해 형태가 복잡하여 기존의 P-CARES 등의 인공 지진파 생성 프로그램을 이용할 경우 SRP 3.7.1의 요건에 맞는 시간 이력 인공 지진파를 얻기 위해서는 상당한 노력이 필요하다. 본 연구에서는 수치 최적화를 이용하여 복잡한 형태의 층응답스펙트럼이 라도 SRP 3.7.1의 요건 내에서 그 형태를 따르는 인공 지진파 시간 이력을 효율적으로 생성할 수 있는 절차를 개발하였다.

The textile tentering process generates exhaust gases characterized by elevated temperature and humidity, accompanied by complex odors, fine particulate matter, and visible white smoke, all of which frequently contribute to public grievances and environmental concerns. This study evaluated a field-installed, multi-stage emissioncontrol system consisting of a scrubber, a wet electrostatic precipitator (WEFC), and a heat exchanger, with emphasis on the effect of routine plate cleaning over a ht ree-month operation. Real-time monitoring at 5-minute intervals measured temperature, humidity, total volatile organic compounds (TVOCs), particulate matter (PM2.5, PM10, TSP), and odor intensity. Odor activity values (OAVs) and odor contributions (OC) were determined from samples collected according to the Korean Odor Measurement Standard. The emission-control system reduced exhaust temperature from 150oC to below 50oC while maintaining stack outlet temperature differences within 5oC, thereby suppressing visible white smoke. The multistage system achieved mean removal efficiencies of 88.6±5.0% for TVOCs and 96.2±6.5% for PM10, with a gravimetric PM10 removal of 99.4%. Weekly cleaning of the electrostatic plates constrained day-to-day variability in odor and PM levels within ±10%, significantly lowering the frequency of white-smoke episodes. Isovaleraldehyde and acetaldehyde accounted for >90% of total OAVs, indicating the need for supplementary treatment targeting aldehydes. These results provide quantitative evidence to guide maintenance scheduling and emission-control policy for the textile processing industry.

현대사회는 식생활개선과 의료기술 발달로 인간수명이 연장되어 노인 인구가 증가함에 따라 노인돌봄에 대한 수요가 늘어나고 있으며 이용대 상자들은 효율적인 서비스를 기대하고 있다. 본 연구의 목적은 요양보 호사의 직무만족을 높이고 요양보호사의 자아존중감과 회복탄력성을 증 진하여 양질의 휴먼 서비스를 제공할 수 있는 방안을 모색하는 데 연구 의 목적이 있다. 요양보호사의 권리존중과 직무만족도 사이에서 회복탄 력성은 매개 역할을 하는 것으로 검증되었다. 따라서 요양보호사의 권 리존중은 회복탄력성을 매개하여 직무만족도에 간접적으로 영향을 미치 는 것으로 검증되었다. 본 연구를 통하여 요양보호사의 직무만족도를 향상시키기 위해 자아존중감과 회복탄력성을 키울 수 있는 대책을 제안 했다는 점에 의의가 있다.

This study aims to analyze the risk factors contributing to marine accidents involving Korean distant water fishing vessels using a Bayesian network approach. As marine accidents in this sector often result in severe casualties and significant economic losses, understanding their underlying causes is critical. Based on official investigation records from the Korea Maritime Safety Tribunal (2000-2023), a dataset of 46 accident cases involving longliners, trawlers, and other fishing vessels was constructed. The analysis categorized accidents by vessel types, gross tonnage, vessel age, location, operating status, and specific causes, including poor lookout and inadequate maintenance. Following the Formal Safety Assessment (FSA) framework recommended by the International Maritime Organization (IMO), the study applied Bayesian networks to quantify the probabilistic relationships among risk factors. The results revealed that the most hazardous conditions for different accident types included: vessels with 300-500 GT, aged 20-40 years, operating outside harbor limits during navigation or fishing. Specifically, collision and grounding incidents were primarily associated with poor lookout, while sinking and fire/explosion incidents were linked to inadequate maintenance. The findings underscore the necessity of tailored safety control measures for each accident type and vessel category. This research provides empirical evidence to support decision-making for improving safety policies under the Act on the Punishment of Serious Accidents and the Distant Water Fisheries Development Act.

This study investigates the effects of canopy fabric material and vent diameter on the deployment performance of sea anchors for fishing operations through field experiments. Three canopy configurations were tested: polyamide (PA), polyester (PES), and a PA – PES alternating combination. Vent diameters of 80 cm and 40 cm were applied to each fabric as controlled structural factors. Deployment performance was evaluated from entrance diameter computed using four evenly spaced water level loggers, and maximum towing tension was recorded with a load cell. Key findings were discovered as follows: PES and the PA – PES mix achieved deployment diameter/ratio and maximum tension comparable to the current PA standard, indicating practical substitutability. PES also exhibited superior stability, showing reduced variability even with the smaller vent (a change in standard deviation ΔSD-1.75 cm). The mixed canopy maintained performance similar to PA. As expected, vent diameter systematically affected geometry and load (80 cm: 187 – 198 kgf vs. 40 cm: 249 – 268 kgf), underscoring the need to pair material selection with appropriate vent sizing. In conclusion, PES and mixed fabrics are viable alternatives to PA, and co-optimization of fabric choice and vent diameter can enhance sea-anchor performance, durability, and operational reliability for fishing operations.

본 연구는 쇄빙연구선 아라온호의 국부 빙하중을 정확하게 추정하기 위해, 국제선급협회(IACS) Polar Class에 따른 실제 설계 하중(Design Ice Load)과 빙하중 면적(Load Patch)을 활용하여 영향계수행렬을 산정하였다. 기존 연구에서는 단위하중 또는 집중하중 형태 로 구조해석을 수행하여 영향계수행렬을 구했으나, 본 연구에서는 아라온호의 설계하중을 기반으로 실제 빙 충돌 상황과 유사한 면적 에 하중을 부여함으로써 보다 현실적인 해석 결과를 얻고자 하였다. 해석에는 선급 규칙으로부터 도출한 직사각형 형태의 빙하중 패치 와 평균 압력을 적용하였으며, 아라온호 선수부에 총 21개의 스트레인 게이지 위치에 대해 각각 해석을 진행하였다. 이후, 각 하중 조건 에서의 변형량을 토대로 21×21 행렬 형태의 영향계수행렬을 도출하였다. 본 연구의 결과로 도출된 영향계수행렬을 사용하면 실제 계측 된 스트레인 값을 기반으로 빙하중을 보다 정밀하게 추정할 수 있을 것으로 기대된다. 이는 기존 방식 대비 얼음 충돌 시 발생하는 면 적 효과를 고려했다는 점에서 의미가 있으며, 향후 쇄빙선 설계 및 운항 과정에서의 빙하중 평가 정확도를 높이는 데 기여할 것으로 판단된다.

In this study, the molten steel flow inside the mold according to the shape change of the submerged entry nozzle (SEN) was simulated in the continuous casting process, and the effects of the immersion depth and long side length of the mold on the molten steel flow were compared and analyzed. The heat flow analysis was performed using the ANSYS Fluent software, and the turbulence model used the standard k-ε model. Based on the analysis results, the meniscus velocity decreased with deeper immersion depth, but it was slightly faster with lower immersion depth. In addition, the flow velocity of the molten steel of the outlet was increased because the molten steel exiting the upper outlet spread directly without colliding with the short side of the mold when the long side of the mold length was increased.