• The Korean Journal of Ecology
• /
• 제27권6호
• /
• pp.363-367
• /
• 2004

Photosynthetically active radiation (PAR) beneath the forest canopy, understory species richness and diversity, and biomass were measured in a Larix leptolepis plantation seven years after thinning in Yangpyeong. Four different thinning intensities (control, $10\%,\;20\%\;and\;40\%$ stocking reduction) were applied in 1997. The current PAR values were lower than those measured four years after thinning, and PAR at the heavy thinning plots was significantly higher than that of other thinning intensities. A total of 23 species including 9 tall-trees and 14 shrubs were found for the high layer while a total of 82 species including 10 tall-trees, 29 shrubs, and 43 herbs for the low layer. Species richness and diversity generally increased with thinning intensities, and the trends were more evident for the low layer. Aboveground biomass significantly differed among thinning intensities for both shrubs and herbs. Also there was a negative correlation between biomass and the current number of stems per hectare. The current study suggested that the effects of thinning on light conditions at the forest floor, species richness and diversity and production of understory vegetation continued seven years after the treatment.

• 한국정보전자통신기술학회논문지
• /
• 제11권6호
• /
• pp.703-710
• /
• 2018

매년 전기화재사고에 대한 사고유형 분석, 점검 등 전기적 화재사고를 줄이기 위해 다양한 노력이 있었으나, 효율적인 의사결정지원 체계 및 기존 누적 데이터 활용방안의 미비로 효과적인 대처방안이 부재한 현황이다. 본 연구는 전기안전점검데이터, 전기화재사고정보, 건축물정보, 기상청정보 등 데이터 기반의 전기화재를 예측하는 알고리즘을 개발하고 이를 활용하여 전기화재사고를 줄이는데 목적이 있다. 본 연구에서는 한국전기안전공사, 기상청, 국토교통부, 소방본부 등 기관별로 수집된 데이터를 전처리, 융합, 분석, 모델링, 검증 과정을 거쳐 전기화재에 영향을 끼치는 요인과 예측모델을 도출하였다. 주요요인으로 절연저항 값, 습도, 풍속, 건축물 노후년수, 용적율, 건폐율, 건축물용도로 나타났고, Random forest 알고리즘을 활용한 예측모델은 74.7%의 정확도를 얻었다.

• 한국환경복원기술학회지
• /
• 제24권6호
• /
• pp.35-48
• /
• 2021

In Suwon, the overall hygiene of the city is threatened by the emergence of the rook(Corvus fugilegus) in the city. Rooks began to appear in November of 2016 and has continued to appear from November to March every year. In order to eradicate or to prepare an alternative habitat for rooks, this study aimed to identify the preferred habitat and specific environmental variables. Therefore, in this work, we aim to understand the predicted distribution of rooks in Suwon City with citizen science and through MaxENT, the most widely utilized habitat modeling using citizen science to analyze the preferred habitat of harmful tides appearing in urban areas. In this study, seven environmental variables were chosen: biotope group complex, building floor, vegetation, euclidean distance from farmland, euclidean distance from streetlamp, and euclidean distance from pole and DEM. Among the estimated models, after the time period of sunrise (08:00~18:00) the contribution percentage were as following: euclidean distance from arable land(39.2%), DEM(25.5%), euclidean distance from streetlamp(22.3%), euclidean distance from pole(7.1%), biotope group complex(4.9%), building floor(1%), vegetation(0%). In the time period after sunset(18:00~08:00) the contribution percentage were as following: biotope group complex(437.4%), euclidean distance from pole(26.8%), DEM(13.4%), euclidean distance from streetlamp(11.8%), euclidean distance from farmland(7.9%), building floor(1.4%), vegetation(1.3%).

• 환경생물
• /
• 제38권4호
• /
• pp.733-743
• /
• 2020

본 연구는 폐탄광에서 산림으로 복구된 지역의 임목, 낙엽층, 토양, 그리고 산림의 총 탄소 저장량을 추정하고, 수종별 탄소 저장량 차이를 비교하기 위해 수행되었다. 이를 위하여 강원도, 경상북도, 전라남도의 폐탄광 산림복구지에서 자작나무, 잣나무, 소나무류(소나무, 리기다소나무, 곰솔)가 서로 다른 시기에 식재된 산림과 주변의 일반 산림을 조사하였다. 일반 산림에 비하여 폐탄광 산림복구지 내 낙엽층 및 토양(ton C ha^-1; 자작나무: 3.31±0.59 및 28.62±2.86, 잣나무: 3.60±0.93 및 22.26±5.72, 소나무류: 4.65±0.92 및 19.95±3.90), 그리고 산림의 총 탄소 저장량(ton C ha^-1; 자작나무: 54.81±7.22, 잣나무: 47.29±8.97, 소나무류: 45.50±6.31)은 낮게 나타났으며, 임목 탄소 저장량(ton C ha^-1; 자작나무: 22.57±6.18, 잣나무: 21.17±8.76, 소나무류: 20.80±6.40)은 자작나무가 식재된 곳에서만 낮은 결과가 나타났다. 수종별로 토양 탄소 저장량을 제외한 임목, 낙엽층, 산림의 총 탄소 저장량에서 차이가 나타나지 않았으며, 임목 및 산림의 총 탄소 저장량은 복구 후 경과시간에 따라 증가하는 경향을 보였다. 한편, 폐탄광 산림복구지의 자작나무와 소나무류에서 토양 pH 및 CEC가 낮게 나타났으며, 수종별 불안정탄소, 유효인산, 미생물 바이오매스 탄소가 일반 산림토양보다 2배 이상 낮은 결과를 보였다. 폐탄광 산림복구지에 석회 및 유기질 비료의 시비와 경운을 통해 토양 성질을 개선하고, 가지치기 및 간벌 등과 같은 산림관리로 임목 생육을 증진시키면 폐탄광 산림복구지 내 탄소 저장량을 증가시킬 수 있을 것으로 기대된다.

• 한국가구학회지
• /
• 제21권1호
• /
• pp.83-96
• /
• 2010

This study explores terminology for legs and feet in the traditional Korean and Western furniture. Pieces of traditional Korean and Western furniture have been largely made of the eco-friendly material, natural wood, and thus important in the latest trends of wellness, such as LOHAS (Lifestyles of Health and Sustainability) and a green period. Legs in traditional Korean furniture appeared in dinging tables, and the feet in wardrobes. The limited use of legs and feet seems to be influenced by floor-oriented lifestyles of Korean ancestors. In contrast, most pieces of Western furniture, which is from the chair and bed culture, have various styles of foot and leg. While th two groups are from different backgrounds, both of them have developed various legs and feet applying natural subjects such as animals and plants to each of their furniture including wardrobes, cabinets, dining tables, chairs, consoles, etc. It is also found that the traditional Korean furniture can be influenced by a traditional Chinese chair foot called Neabunmajae, which describes inner horse foot. Neabunmajae was known in Korean furniture legs and feet, but the terminology has not been known. The study suggests that terms which appear in traditional furniture but are unknown should be studied more.

• 한국태양에너지학회 논문집
• /
• 제40권4호
• /
• pp.35-44
• /
• 2020

Currently, various policies regarding ecofriendly vehicles are being proposed to reduce carbon emissions. In this study, the required areas for charging electric vehicle (EV) batteries using electricity produced by photovoltaic (PV) power plants were estimated. First, approximately 2.4 million battery EVs, which represented 10% of the total number of vehicles, consume approximately 404 GWh. Second, the power required for charging batteries is approximately 0.3 GW, and the site area of the PV power plant is 4.62 ㎢, which accounts for 0.005% of the national territory. Third, from the available sites of buildings based on the region, Jeju alone consumes approximately 0.2%, while the rest of the region requires approximately 0.1%. Fourth, Seoul, which has the smallest available area of mountains and farmlands, utilizes 0.34% of the site for PV power plants, while the other parts of the region use less than 0.1%. The results of this study confirmed that the area of the PV power plant site for producing battery-charging power generated through the supply of EVs is very small. Therefore, it is desirable to analyze and implement more specific plans, such as efficient land use, forest damage minimization, and safe maintenance, to expand renewable energy, including PV power.

• Steel and Composite Structures
• /
• 제51권5호
• /
• pp.563-573
• /
• 2024

This research experimentally evaluated the local stress distribution along the cross-section of composite beams under both positive and negative moments. The experiment utilized a large-scale, two-story, two-by-three bay steel gravity frame with a concrete on metal deck floor system. The composite shear connections, which are nominally assumed to be pinned under gravity loading, can develop non-negligible moment-resisting capacity when subjected to lateral loads. This paper discusses the local stress distribution, orshear lag effects, observed near the beam-to-column connections when subjected to combined gravity and lateral loading. Strain gauges were used for measurements along the beam depth at varying distances from the connection. The experimental data showed amplified shear lag effects near the unconnected region of the beam web and bottom flange under the applied loading conditions. These results indicate that strain does not vary linearly across the beam cross-section adjacent to the connection components. This insight has implications for the use of experimental strain gauge data in estimating beam demands near the connections. These findings can be beneficial in informing instrumentation plans for future experimental studies on composite beams.

• Journal of the Korean Wood Science and Technology
• /
• 제36권6호
• /
• pp.77-87
• /
• 2008

국내산 주요 침엽수 소경목의 활용 방안으로 리기다소나무를 이용한 목재 모형 사방댐을 제작하여 강도 성능을 평가하였다. 목재 모형 사방댐은 직경 90 mm의 CUAZ-2 (Copper Azole) 처리한 리기다소나무 방부 원주목을 사용하여 3 Type으로 접합부를 달리하여 제작하였다. 각 Type별 사방댐은 횡목 5층 종목 4층 총 9층의 높이 790 mm로 제작 하였으며 수평 재하 시험과 충격 시험을 통한 강도 성능 평가와 화상처리를 통한 구조물의 변형을 검토 하였다. 직경 90 mm의 원주목을 사용한 목재 모형 사방댐의 수평 재하 시험 결과 직결나사를 사용한 경우 쇄석의 유무는 강도에 큰 영향을 미치지 않았지만 변형은 23% 감소하였다. 전선볼트를 사용한 일체형 사방댐의 경우 쇄석을 채운 경우 1.5배 강도가 증가하고 변형은 감소하였다. 직결나사에 고리가 달린 전선볼트로 보강한 경우 4.8배 강도가 증가하였다. 직경 90 mm 목재 모형 사방댐의 충격 시험 결과 쇄석을 채우지 않은 직결나사 사방댐은 1회 충격에 구조물 전체가 파괴되었으며 전선볼트를 사용한 사방댐은 1회 충격시 779 kgf의 충격이 직접적으로 가해지는 횡목에서 파괴되었다. 2회 충격시 기초부가 파괴되며 545 kgf로 반력이 감소하였고 3회 충격시 기초부 전체가 파괴되며 263 kgf로 반력이 감소하였다.

• 한국농림기상학회:학술대회논문집
• /
• 한국농림기상학회 2013년도 추계 학술발표논문집
• /
• pp.23-24
• /
• 2013

Micrometeorological fluxes measured over a tall forest in a complex terrain are difficult to interpret. $CO_2$ storage often makes significant contributions to net ecosystem exchange of $CO_2$ (NEE) in early morning and during nighttime due to calm and stable conditions. We measured the above-canopy $CO_2$ flux along with its concentration profiles at eight levels within and above the canopy to evaluate $CO_2$ storage term. Our question is whether or not the $CO_2$ storage term can be estimated accurately from a single level measurement of $CO_2$ concentration in a complex terrain. Our objectives are (1) to document vertical profiles of $CO_2$ concentration and (2) to compare the diurnal and seasonal variations of $CO_2$ storages estimated from single and multi-level $CO_2$ concentration data. Seasonally averaged Diurnal variations of $CO_2$ concentration ranged from 398 to 455 ppm near the forest floor at 0.1 m whereas they ranged from 364 to 395 ppm at 40 m in the atmosphere. The diurnal variation of vertical profiles of $CO_2$ concentration shows very interesting features with season. At all eight levels, diurnal variation of $CO_2$ concentration showed little change in winter. In spring, the diurnal variations of $CO_2$ concentration at 8 levels showed three distinct groups of layers with height: the first layer: 0.1m (near surface), second layer: 1.0 m and 4.0m (below canopy) and the third layer: 7.4m to 40.7 m (near canopy and above). In summer, these three groups of layers were further separated with larger variations whereas such distinction became smaller in fall. The diurnal variation of $CO_2$ concentration in the first three layers near surface always showed higher concentration with larger variability. Typically, $CO_2$ concentration showed peaks in early morning and in the evening. After the evening peak, $CO_2$ concentration gradually increased except for those near the surface (i.e., 0.1, 1.0 and 4.0 m) where the concentrations actually decreased. We suspect that this could be attributed to the drainage flow of $CO_2$ along the hill slope from the headwater to downstream, which is not taken into account for net ecosystem $CO_2$ exchange. In comparison to the results of other studies, the distinct and different vertical structures of $CO_2$ concentrations observed at our site may be due to complex terrain and weak turbulent mixing under calm conditions at the site. The annual mean of diurnal variation of $CO_2$ storage flux from single level ranged from -0.6 to $0.9{\mu}mol\;m^{-2}s^{-1}$ and from multi-level from -1.2 to $1.0{\mu}\;{\mu}mol\;m^{-2}s^{-1}$. When compared against the results from the multi-level concentrations, the storage flux estimated from a single-level concentration was generally adequate except for specific hours near sunrise and sunset. Further details and their implication will be discussed in the presentation.

• 한국환경생태학회지
• /
• 제11권3호
• /
• pp.334-351
• /
• 1997

난대 상록활엽수림 복원 모형 연구의 사례지인 완도의 식생구조를 조사하였다. 완도의 사록활엽수림은 붉가시나무가 우점종이었으며, 수령 30여년 미만의 맹아림이 대부분이었다. 중복부와 산록부에는 조림식생과 낙엽활엽수림이, 능선부와 고지대에는 졸참나무, 개서어나무, 소사나무 등의 낙엽활엽수림이 발달하고 있었으며, 임상층에서 상록활엽수종이 활착하고 있었다. 47개 조사구에서 60% 이상의 상재도를 나타낸 상록활엽수종은 광나무, 마삭줄, 붉가시나무, 사스레피나무이었다. 본 조사지역 내에 출현한 관속식물상은 101과 321속 426종 56변종, 5품종 및 1교잡종 등 촌 488종류로 파악되었으며 이 중에서 상록성 수목은 23속 30종 2변종 등 32종류이었다. 12개 조사지역에서 100%의 상재도를 나타낸 종은 맥문동과 칡이었으며, 50% 이상인 종은 덜꿩나무, 마삭줄 등 40종류이었다. 한편 상재도가 8% 이하인 식물종은 가래나무, 말채나무, 병아리꽃나무 등 209종류이었다. 식물종 다양성은 장기간 인간간섭으로 조사지역간 특이한 사항은 보이지 않았으나, 곰솔림이 155종으로 가장 높은 값을 보인 반면에 생달나무-마삭줄군락은 23종으로 가장 낮은 값을 나타내었다.