• 한국화재소방학회논문지
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• 제23권4호
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• pp.120-129
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• 2009

건축물 화재에서는 발화물과 주변 가연물이 소실하기 때문에 화재현장 조사만으로 출화원인을 규명하기 어렵다. 따라서 본 연구는 현장조사와 화재실험을 통해 화재의 원인과 확대과정을 추정하는 방법에 관하여 고찰하였다. 본 연구에서는 화재원인 불명으로 판단된 공동주택의 화재사례를 대상으로 현장의 잔존물에서 출화장소와 초기연소물을 추정하고, 출화물로 추정된 가연물을 대상으로 연소실험을 실행하여 출화원인 등을 추정하였다. 화재실험에서는 가연물의 종류 및 배치 등을 출화이전의 상태로 재현하고 출화조건을 가정하여 반복적으로 실행하여 연소 후의 상황과 화재현장의 잔존물을 비교함으로써 출화원인 및 초기 화재확대과정을 규명하였다.

• 농촌계획
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• 제21권4호
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• pp.35-43
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• 2015

The purpose of the research is to analyze damages of TYLCV (Tomato Yellow Leaf Curl Virus) in the context of climate changes and to find the spatial distribution of the damages and characteristics of regions. A TYLCV is generally known for a plant disease related to temperature. Its occurrence rate increases when temperature rises. This disease first occurred in 2008 and rapidly spread nationwide. Due to the spread of a TYLCV, a number of Tomato farms in Korea were damaged severely. To analyze damages of the pest in the context of climate changes, this research estimated production loss under the current situation and RCP scenarios. Additionally, Hot Spot Analysis, LISA, and Cluster analysis were conducted to find spatial distribution and properties of largely damaged regions under RCP scenarios. The results explained that additional production loss was estimated differently by regions with the same temperature rising scenario. Also, largely damaged regions are spatially clustered and factors causing large damages were different across regional cluster groups. It means that certain regions can be damaged more than others by diseases and pests. Furthermore, pest management policy should reflect the properties of each region such as climate conditions, cultivate environment and production technologies. The findings from this research can be utilized for developing rural management plans and pest protection policies.

• 대한원격탐사학회지
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• 제36권1호
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• pp.29-39
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• 2020

Forest fire is a critical disaster that causes massive destruction of forest ecosystem and economic loss. Hence, accurate estimation of the burned area is important for evaluation of the degree of damage and for preparing baseline data for recovery. Since most of the area size damaged by wildfires in Korea is less than 1 ha, it is necessary to use satellite or drone images with a resolution of less than 10m for detecting the damage area. This paper aims to detect wildfire-damaged area from a Kompsat-3 image using the indices such as NDVI (normalized difference vegetation index) and FBI (fire burn index) and to examine the classification characteristics according to the methods such as Otsu thresholding and ISODATA(iterative self-organizing data analysis technique). To mitigate the salt-and-pepper phenomenon of the pixel-based classification, a gaussian filter was applied to the images of NDVI and FBI. Otsu thresholding and ISODATA could distinguish the burned forest from normal forest appropriately, and the salt-and-pepper phenomenon at the boundaries of burned forest was reduced by the gaussian filter. The result from ISODATA with gaussian filter using NDVI was closest to the official record of damage area (56.9 ha) published by the Korea Forest Service. Unlike Otsu thresholding for binary classification,since the ISODATA categorizes the images into multiple classes such as(1)severely burned area, (2) moderately burned area, (3) mixture of burned and unburned areas, and (4) unburned area, the characteristics of the boundaries consisting of burned and normal forests can be better expressed. It is expected that our approach can be utilized for the high-resolution images obtained from other satellites and drones.

• Structural Engineering and Mechanics
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• 제58권5호
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• pp.757-781
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• 2016

The results of diagnostics and analysis of an industrial hall located on the premises of a thermal power plant severely damaged by fire are presented in the paper. The comprehensive failure-related diagnostics, non-destructive and destructive tests of steel and concrete materials, geodetic surveying of selected structural members, numerical modelling, static analysis and reliability assessment were focused on two basic goals: The determination of the current technical condition of the load bearing structure and the assessment of its post fire resistance as well as assessing the degree of damage and subsequent design of reconstruction measures and arrangements which would enable the safe and reliable use of the building. The current mechanical properties of the steel material obtained from the tests and measured geometric characteristics of the structural members with imperfections were employed in finite element models to study the post-fire behaviour of the structure. In order to compare the behaviour of the numerically modelled steel roof truss, subjected to the effects of fire, with the real post-fire response of the damaged structure theoretically obtained resistance, critical temperature and the time at which the structure no longer meets the required reliability criteria under its given loading are compared with real values. A very good agreement between the simulated results and real characteristics of the structure after the fire was observed.

• Tribology and Lubricants
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• 제18권2호
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• pp.167-172
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• 2002

The wear behaviors of ultrahigh molecular weight polyethylene pins against titanium alloy and stainless steel disks moving in two different kinematic motion were investigated by conducting repeat pass rotational sliding and linear reciprocal sliding wear tests. Linear reciprocal motion wore more the polyethylene pin than did repeat pass rotational motion for both disk materials. It means that the repeated directional change of contact stresses generates more wear debris in polyethylene. For the linear reciprocal sliding tests, titanium alloy disks were damaged with some scratches after one million cycles but no surface damage was observed on the polyethylene pins. On the other hand, fur the repeat pass rotational sliding tests, all titanium alloy disks were severely abraded on the entire region of sliding track. This phenomenon can be interpreted by that stress fatigue under repeated sliding contact initiated titanium oxide layer wear particles from disk surface, and these hard particles were embedded into polyethylene pin and then they severely abraded the disk surface. From these results it can be concluded that the kinematic motion in pin-on-disk wear tests play a crucial role on the wear behaviors of UHMWPE pins against titanium alloy and stainless steef discs.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2000년도 제32회 추계학술대회 정기총회
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• pp.67-71
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• 2000

The wear behaviors of ultrahigh molecular weight polyethylene pins against titanium alloy and stainless steel disks moving in two different kinematic motion were investigated by conducting repeat pass rotational sliding and linear reciprocal sliding wear tests. Linear reciprocal motion wore more the polyethylene pin than did repeat pass rotational motion for both disk materials. It means that the repeated directional change of contact stresses generates more wear debris in polyethylene. For the linear reciprocal sliding tests, titanium alloy disks were damaged with some scratches after one million cycles but no surface damage was observed on the polyethylene pins. On the other hand, for the repeat pass rotational sliding tests, all titanium alloy disks were severely abraded on the entire region of sliding track. This phenomenon can be interpreted by that stress fatigue under repeated sliding contact initiated titanium oxide layer wear particles from disk surface, and these hard particles were embedded into polyethylene pin and then they severely abraded the disk surface. From these results it can be concluded that the kinematic motion in pin-on-disk wear tests play a crucial role on the wear behaviors of UHMWPE pins against titanium alloy and stainless steel disks.

• 한국작물학회지
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• 제59권4호
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• pp.427-434
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• 2014

1. 생산지에 따라 벼 종자의 수발아립률 차이가 컸던 호품벼의 출아율과 발아율을 조사한 결과, 수발아율 8%인 시료는 수발아율이 1%인 시료에 비해 발아율과 출아율, 종자활력이 30% 낮았다. 2. 수발아율이 높은 시료는 수발아립의 변색 정도가 심하고 미발아율과 부패율이 높았다. 수발아립은 배가 돌출하고, 변색된 배유와 곰팡이 감염이 관찰되었으며 배유의 1/2이상이 변색된 종자는 발아율이 매우 낮았다. 3. 종자의 발아 진행정도에 따라 현미의 변색이 심해졌는데, 싹이 3 mm이상일 경우 배유의 1/2정도가 변색되었다. 4. 발아 종자는 싹이 3 mm이상일 때부터 재발아율이 크게 떨어졌으며 퇴화촉진처리 후 발아율의 감소가 더 컸다. 특히 퇴화촉진처리한 발아 종자는 싹이 2 mm부터 종자활력이 크게 감소하였다. 결론적으로 수발아 발생이 심할수록 파종기 발아율과 출아율의 감소가 크고, 수발아가 3 mm이상 발생하면 발아율이 크게 저하될 것으로 생각된다. 또한 수발아는 동일 품종과 동일 지역에서도 포장 간 차이가 크게 발생할 수 있으므로 재배관리에 주의해야 한다.

• 한국산림과학회지
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• 제79권1호
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• pp.21-25
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• 1990

경기(京畿) 광주군(廣州郡)의 적송림(赤松林)을 대상으로 솔잎혹파리극심피해시기(極甚被害時期) 및 피해회복시기(被害回復時期)의 삼림군집구조(森林群集構造)의 변화내용을 분석하였다. 극심피해시기인 1980년에 4개의 조사구(調査區)를 선정하고 각 조사구에 5개씩의 소조사구(小調査區)를 설치한후 식생조사를 하였으며 피해회복시기인 1987년에 동일장소에서 재조사를 실시하였다. 1980년의 출현종수(出現種數)는 39종, 1987년에는 41종으로 큰 차이는 없었다. 솔잎혹파리피해가 회복됨에따라, 피해가 심하였을때 소나무군집의 대상수종(代償樹種)으로 나타난 참나무류의 우점치(優占値)가 낮아지고, 서어나무, 팥배나무, 쪽동백나무의 상대우점치가 다른 수종보다 증가하였으며, 7년간의 종구성상태(種構成狀態)가 변화함에 따라 종다양도(種多樣度), 균재도등(均在度等)도 증가하였다. 1980년과 1987년의 조사군집간(調査群集間)의 유사도지수(類似度指數)는 74.5%이었고 교목상(喬木上) 하층(下層) 및 관목층(灌木層)에서 각각 87.5, 52.9%, 51.9%로서 교목하층과 관목층의 종구성상태가 교목상층보다 이질화 하였다.

• 한국응용곤충학회지
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• 제42권3호
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• pp.263-267
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• 2003

감관총채벌레가 2000년에 처음으로 보고된 이후 남부지방에서 계속 분포가 확산되고 있어서 설문조사를 통해 그 분포확산 정도를 조사하였다. 조사결과 감관총채벌레는 1995년에 전남 장성군에서 최초로 발생하였으며, 현재는 울산광역시와 충북, 전북, 전남, 경북, 경남, 제주 등 6개 도의 26개 시군에서 발생하고 있고, 경남의 창원과 밀양 지역이 피해가 가장 심하였다. 1995년부터 2003년 4월까지 누적된 발생면적은 총 151 ha이었으며, 단감 뿐만 아니라 떫은감에도 발생하였다.

• 한국공간구조학회논문집
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• 제19권4호
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• pp.77-84
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• 2019

This study introduces a newly developed PC non-bearing wall system to prevent the damage of RC wall-type apartments that have been heavily damaged by the 2017 Pohang Earthquake. In order to evaluate the performance of the developed PC non-bearing wall system, a static cyclic test is conducted. The prototype of test specimen is from the RC wall-type apartment which has been severely damaged by the 2017 Pohang Earthquake. The specimen with the conventional non-bearing wall system showed the similar damage of RC wall type apartment suffered from the Pohang Earthquake. In case of the specimen with the developed PC non-bearing wall system, cracks and damages were not transmitted between the walls due to the seismic slit and there were almost no cracks in the non-bearing walls. Therefore, the proposed non-bearing wall system, separated from the structural walls, could prevent spreading cracks to bearing walls and make it possible to effectively control damage due to earthquake loads.