To conduct a comprehensive assessment of aquatic ecosystems, it is necessary to understand the characteristics of lentic ecosystems such as lakes, in addition to rivers. This requires analyzing the characteristics of biological communities in lakes and developing appropriate assessment indices. In this study, we analyzed the distributional characteristics of benthic macroinvertebrate communities collected from 90 lakes between 2022 and 2024, according to four categories of lake types (inflow stream type, lake size, salinity characteristics, and trophic states). The environmental variables used to classify lake types (catchment area, altitude, area of water, electrical conductivity, total phosphorus, and chlorophyll-a) all followed a log-normal distribution with positive skewness. Most of the lake types were characterized by inflow from lowland small streams, small or middle size, and freshwater lakes. However, in terms of trophic states, many lakes were assessed as mesotrophic or eutrophic. Analysis of seven community structure characteristics (taxa richness, taxa abundance, dominance, diversity, richness, evenness, and Lake Benthic Macroinvertebrate Assessment Index, LBAI) and two functional groups (feeding and habitat) showed clear changes primarily associated with trophic states, while other lake types showed irregular increase or decrease or similar levels. In the CCA, which analyzed dominant taxa by abundance and six environmental variables, the distribution patterns of lakes were more clearly distinguished by salinity characteristics related to electrical conductivity, unlike the community indices. The results of this study are expected to serve as basic data for future monitoring and assessment of lake aquatic ecosystems using benthic macroinvertebrates.
Within the Pungnap-dong Earthen Fortress in Seoul, various archaeological remains and artifacts that constitute an ancient capital have been excavated, including residential sites from the Proto-Three Kingdoms period to the Hanseong period of Baekje, as well as public buildings, ritual facilities, large-scale waste pits, pit dwellings, roads, waterways, and earthen fortess. The reconstruction focuses on Building Site No. 44 in the Gyeongdang zone and Pit-Dwelling Site No. Ga-30 in the Mirae Village area. Based on the traces of these structures, the study reconstructs various architectural elements, including floor plans, foundation construction methods, flooring treatments, pillar arrangements and frameworks, wall construction techniques and openings, as well as roof materials and forms. Building Site No. 44 in the Gyeongdang zone exhibits features characteristic of a transition to above-ground architecture, such as a rectangular floor plan, the construction of a separate foundation, a deliberately planned pillar layout, and independently built walls. Pit-Dwelling Site No. Ga-30 in the Mirae Village area, on the other hand, was designed as a pit structure with thick load-bearing walls to create a large interior space, differing from earlier forms. In this case, materials such as wood, stone, and earth were combined, reflecting an understanding of the distinct properties of each material. The significance of this study lies in the discovery that, although both buildings share similarities with pit dwellings in terms of floor plan and certain structural aspects, they also reveal attempts to implement new wall construction techniques in order to elevate the structures above ground and to construct large-scale buildings.
베일러는 대표적인 수확 기계 중 하나로 건초, 볏짚 등의 사료 작물을 압축하여 베일을 생성함으로써 축산 농가에서 사용할 수 있도록 한다. 현재까지 국내에서는 80kW 미만의 트랙터 및 베일러 작업 부하에 대한 연구는 다수 수행되었으나, 80kW급 이상의 대형 트랙터 및 베일러를 활용한 작업 부하와 관련된 연구는 부족한 실정이다. 본 연구에서는 대형 베일러 실 작업시 트랙터에 가해지는 부하를 전륜, 후륜 및 PTO 동력 부하와 전체 동력계통 부하 소요의 관점에서 분석하고자 하였으며, 시험 결과를 활용하여 베일러 작업 시 세부작업별 동력 소요 특성과 소요 동력의 크기 등을 확인하였다. 분석 결과 작업이 시작되는 구간에서 차축의 소요 동력이 급격하게 증가하였으며, 베일링 작업 중에는 후차축 대비 전차축의 동력 소요가 상대적으로 훨씬 크게 나타나고 PTO에서 가장 큰 동력이 소요됨을 확인하였다. 또한, 등가부하를 기준으로 트랙터 정격출력 대비 약 46~47%의 합산 동력이 소요되는 것을 확인하였으며, PTO의 경우 전체 작업 구간 동안 정격출력 대비 약 24~25% 수준으로 동력이 소요되는 것을 확인하였다.
In this paper, we examined how large beams were developed in Korea, China, and Japan in the 6th and 8th centuries, and how this pattern affected Korean architecture later. A large inner space was required to symbolize the authority of the emperor and king and to achieve the purpose of enshrinement of a large Buddha statue forming a cluster, and a large beam over 9m was used to implement this. The use of large beams is confirmed from the late 4th century in China and from the late 5th century at the Seoyeongchonsa Temple Site in Nanjing. In Korea, it is identified from the Lecture hall of Neungsan Risa Temple Site in Baekje(567) and from the middle Buddhist shrine Temple in Hwangnyongsa Temple in Silla(584). Goguryeo is presumed to be around the 6th century, a little earlier than that. In Japan, large beams were used for the first time at the the Lecture hall of Bijosa Temple in 588, which was built by a Baekje engineer. From ancient times to the modern era, the inner space length of the Korean, Chinese, and Japanese architecture was exceptional in some cases, but 9-12m was common. This is judged to be the result of the experience of the material limitation of wood and the size of the inner space established in ancient architecture affecting future generations as a precedent.
본 연구는 2024년 11월 제주 해상에서 발생한 금성 135호 침몰 사고를 중심으로 고등어 대형선망 어업에서의 침몰 사고 원인을 분석하고, 안전성 강화를 위한 개선 방안을 제시하고자한다. 국내 대형선망 어업은 대규모 어획 작업의 특성상 어획물 이동과 복원력 감 소의 위험이 내재되어 있으며, 이는 선박 침몰 사고의 주요 원인으로 작용할 수 있다. 금성 135호 사고는 대량 어획 작업 중 어획물 이동 과 복원력 상실이 복합적으로 작용했을 가능성이 제기되며, 사고 원인이 아직 명확히 규명되지 않았음에도 초기 정황과 분석을 통해 주 요 위험 요소를 파악할 수 있었다. 본 연구는 등선 위치 조정, 자동 장력 조절 장치 및 실시간 하중 모니터링 시스템 도입, 그리고 복원성 기준 개선과 같은 구체적인 개선 방안을 제안한다. 이러한 방안은 하중 이동과 복원력 저하로 인한 사고 위험을 효과적으로 줄이고, 대량 어획 작업의 안정성과 안전성을 동시에 강화할 수 있다. 결론적으로, 금성 135호 사고는 대형선망 어업의 특수성을 반영한 안전 기준 마 련과 기술적 개선의 필요성을 시사하며, 본 연구에서 제시한 개선 방안은 유사 사고를 예방하고 어업 현장의 안전성을 높이는 데 기여할 것으로 기대된다. 본 연구는 대형선망 어업의 작업 안정성을 향상시키기 위한 실질적인 정책적·기술적 대응책 마련에 중요한 자료를 제 공한다.
본 연구는 2003년 산림청 산불 공식 통계 기록 이후 서해안 지역에서 발생한 최대 규모의 산불인 2023년 충청남도 홍성 산불을 사례로, 대형 산불과 환경 특성 간의 관계를 분석하였다. 산불 피해 지역과 피해 강도 분석에는 Sentinel-2 위성 영상을 활용하였으며, 산불피해에 영향을 주는 환경특성으로 도로 밀도, 해발고, 식생 유형을 살펴보았다. 결과적 으로, 오스트리아 산림도로 기준에 따른 도로 밀도는 134.7m/ha로 산림 전역에 도로가 밀집해 있었고, 도로에 가까울수 록 피해 면적이 커지는 경향이 확인되었다. 반면, 해발고는 뚜렷한 상관관계가 없었는데, 이는 연구 대상지가 대부분 낮은 구릉지대에 위치한 데 기인한 것으로 판단되었다. 산불 피해와 가장 밀접한 연관을 보인 요인은 식생 유형으로, 소나무 단순림으로 이루어진 침엽수림의 피해 면적이 전체의 80.1%를 차지하였고, 피해 강도 역시 가장 높았다. 한국의 소나무림은 활엽수림으로의 자연 천이가 빠르게 진행되는 경향이 있으므로, 산불 피해를 줄이기 위해서는 이러한 천이 과정을 저해하지 않는 관리 방식이 효과적일 것으로 보인다. 더불어, 산불 대책으로 현재 추진 중인 산림도로 확대 사업은 산불 피해 경감에 실질적인 도움이 되지 않는 것으로 분석되었다.
Habitat environment and food sources of fish, benthic macroinvertebrates, and brown trout (Salmo trutta) downstream of Soyang River Dam were analyzed. Water temperature at the site where brown trout was identified ranged from approximately 12.4 to 13.4°C, confirming that this environment could provide an optimal water temperature for the growth of brown trout. Most of the riverbed structures at this site had a high proportion of cobble and pebble substrates. Brown trout constituted less than 5% of the total fish population, more abundant in the upstream. The total lengthweight relationship of brown trout showed a parameter b value of 3.234, with the condition factor (K) increasing with length. Dominant benthic macroinvertebrates were Limnodrilus gotoi and Chironomidae spp. (non-red type). Stomach content analysis indicated that brown trout primarily consumed aquatic insects (R.A., 73.8%), non-insects (R.A., 23.3%), ground insects (R.A., 2.7%), and fish (R.A., 0.2%, TL: 246 mm). Correlation analysis revealed a positive relationship between total length and species preferring flowing water (p<0.05) and a negative relationship of total length with species favoring low-flow, sandy habitats (p<0.05). Larger brown trout showed active feeding behavior and resilience to flow speed and riverbed structure. The primary food source for the largest brown trout (TL: 246 mm) was Hypomesus nipponensis. Future analyses should include brown trout with a total length of 30 cm or more. Given that samples were limited, comprehensive population management will require ongoing research.
The purpose of this study is to use an evacuation simulation program to measure the change in evacuation time according to the width of the evacuation route due to the installation of an intermediate sales counter and the placement of a shopping cart between the sales counters of a large supermarket and to analyze the results. Currently, the “Distribution Industry Development Act” does not regulate the size and installation method of intermediate sales counters installed between sales counters that serve as practical evacuation routes in the event of a fire at a large supermarket, the size of shopping carts, etc. Considering this, we set evacuation route widths of 40, 50, 60, 70, 80, and 100 cm and compared and analyzed evacuation times according to various variables in the facility space. As a result of the experiment, as the width of the evacuation route was expanded, there was a significant difference in the evacuation time, from a maximum of 468.3 seconds to a minimum of 320.8 seconds. Considering the safety of evacuees in large supermarkets used by many people, it is time to regulate the size of intermediate sales stands installed between sales counters in large supermarkets and shopping carts that can become obstacles in an emergency.
자동차운반선의 목포신항 도선 비율이 증가하고 있으며, 선박이 대형화되고 있다. 본 연구에서는 목포신항에 입항하는 7,500 unit 자동차운반선의 안전한 접이안을 위한 예선의 소요마력을 산출하기 위해 풍압력과 유압력을 계산하였다. 목포신항 자동차부두는 부 두로부터 1.0 km 떨어진 지점에서 최대 창조류와 최대 낙조류가 각각 1.6 kts와 0.7 kts이며, 조류가 최대인 조건에서는 ‘낙조류와 서풍’인 경우의 일부 구간에서만 예선사용기준을 만족하고 나머지 상황에서는 만족하지 못하는 것으로 평가되었다. 조류가 0.5 kts인 조건에서는 ‘낙조류와 동풍’인 경우 외력의 방향이 상호 일치하여 작용한 일부 구간에서 예선사용기준을 만족하고, ‘창조류와 서풍’인 경우에는 풍속 18 kts 이상에서 만족하지 못하는 것으로 평가되었다. 또한, 조류가 없는 상황에서는 풍속이 21 kts 이상이 되면 현행 예선사용기준을 만족 하지 못하는 것으로 평가되었다. 따라서 목포신항에 입항하는 70,000 G/T 전후의 대형 자동차운반선은 선박의 접이안 시점을 유속 0.5 kts 미만인 시점으로 계획하거나, 조류가 0.5 kts 이상인 경우와 풍속이 20 kts를 초과할 경우에는 예선의 사용마력을 적절히 상향해야 할 것으 로 판단된다.
This study was attempted to investigate effects of ethical climate and workplace bullying on nurses’ turnover intention of nurses working in medium to large sized general hospitals in Korea. This study was conducted on 187 full-time nurses working in the general hospitals with more than 400 beds. Data were collected from the online communities of nurses using Google Foam from April 22 to April 24, 2024. The average values were 3.64±0.64 (out of 5 points) for ethical climate, 2.43±0.75 (out of 4 points) for workplace bullying, and 3.33±0.95 (out of 5 points) for nurses’ turnover intention. While ethical climate had a non-significant relationship with nurses' turnover intention, workplace bullying had a significant relationship with nurses' turnover intention. Nurses’ turnover intention was influenced by verbal attack, inappropriate task, working department, and educational level. These four variables can explain 53.0% of nurses' turnover intention. To prevent the turnover of nurses working at medium to large sized general hospitals, nursing managers need to pay more attention to nurses with low educational level and working at comprehensive wards and special wards. In addition, nursing managers should provide communication training to nurses and assign nursing tasks and working departments according to the nurses' abilities and wishes.
부산 신항에 2020년부터 24,000 TEU급 초대형 컨테이너선이 입항하기 시작하였다. 본 연구에서는 부산 신항을 대상으로 24,000 TEU급 초대형 컨테이너선의 안전한 접․이안을 위한 예선의 소요마력을 산출하기 위해 선체에 작용하는 풍압력과 유압력을 계산하였다. 풍속이 10m/s(20kts)일 때, 13,000 TEU 컨테이너선의 경우에는 현행 「부산항 예선 운영세칙」의 예선의 소요마력 기준을 만족하나, 16,000 TEU 및 24,000 TEU 컨테이너선의 경우에는 그 규정을 만족하지 못하는 것으로 나타났다. 따라서, 현행 예선사용 기준의 최대선박인 ‘G/T 15만톤 이상’의 선박 규모를 2단계로 분할하여 예선 사용기준을 상향하는 방안을 제시하였다. 14만톤은 12,100마력, 17만톤은 14,500마력, 23만톤은 18,000마력의 예선이 요구되므로, 15만톤 이상~20만톤 미만은 16,000마력, 20만톤 이상은 18,000마력으로 예선의 사용기준 개선안 을 제시하였다.
Most wetlands worldwide have suffered from extensive human exploitation. Unfortunately they have been less explored compared to river and lake ecosystems despite their ecological importance and economic values. This is the same case in Korea. This study was aimed to estimate the assemblage attributes and distribution characteristics of benthic macroinvertebrates for fifty wetlands distributed throughout subtropical Jeju Island in 2021. A total of 133 taxa were identified during survey periods belonging to 53 families, 19 orders, 5 classes and 3 phyla. Taxa richness ranged from 4 to 31 taxa per wetland with an average of 17.5 taxa. Taxa richness and abundance of predatory insect groups such as Odonata, Hemiptera and Coleoptera respectively accounted for 67.7% and 68.2% of the total. Among them Coleoptera were the most diverse and abundant. Taxa richness and abundance did not significantly differ from each wetland type classified in accordance with the National Wetland Classification System. There were three endangered species (Clithon retropictum, Lethocerus deyrolli and Cybister (Cybister) chinensis) and several restrictively distributed species only in Jeju Island. Cluster analysis based on the similarity in the benthic macroinvertebrate composition largely classified 50 wetlands into two major clusters: small wetlands located in lowland areas and medium-sized wetlands in middle mountainous regions. All cluster groups displayed significant differences in wetland area, long axis, percentage of fine particles and macrophyte composition ratio. Indicator Species Analysis selected 19 important indicators with the highest indicator value of Ceriagrion melanurum at 63%, followed by Noterus japonicus (59%) and Polypylis hemisphaerula (58%). Our results are expected to provide fundamental information on the biodiversity and habitat environments for benthic macroinvertebrates in wetland ecosystems, consequently helping to establish conservation and restoration plans for small wetlands relatively vulnerable to human disturbance.
In the case of the companies selected for noise measurement in this study, even though noise exposure in the workplace begins with noise management for large machines or high-output machines, they only manage to write reports on how much workers are exposed to noise for 8 hours a day. is focused on. When large machines are delivered, little information on noise received from the manufacturer is kept, and noise information indicated on design drawings is also difficult to find. History management of noise information of large machines is necessary. There is also a problem with the professionalism of managers who manage noise information. Like odors and fine dust, it is judged that noise needs to be managed by a professional manager at the workplace and managed through a database of noise information.