• 제목/요약/키워드: Natural occurrence

검색결과 786건 처리시간 0.026초

지표면의 수분분포가 야생초본류의 발생에 미치는 영향 (The Effects of Soil Surface Moisture Distribution in Perlite on Occurrence of Wild Plants)

  • 박인영;김민수
    • 한국환경복원기술학회지
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    • 제4권1호
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    • pp.16-23
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    • 2001
  • This study was conducted to analyse the relation between physical characteristics of soil surface and wild plants occurrence. Lots of natural occurrence on loamy soil and a little of natural occurrence on perlite. Those were used to observe the wild plants occurrence through the duration. Natural occurrence of wild plants were observed on uniform sand, perlite, loamy soil and 2cms loamy soil layer above the perlite. Uniform sand was compared with different height of drain ditch. The results of analysis were as followed. 1. Wild plants germinated on the uniform perlite layer, they did not grow larger. Because water in large pores of perlite surface drained rapidly and evaporated easily, therefore surface remained low moisture contents. 2. A lot of weed grew on 2cms loamy layer on perlite which stratified above the perlite layer. Because perlite had plenty of soil moisture and soil moisture moved easily from perlite to loamy soil layer. 3. Uniform loamy soil had similar occurrence on the uniform perlite. It was nearly same at surface moisture distribution but lower than layered loamy soil on perlite, and the vertical distributions at soil moisture was totally lower than 2cms loamy soil layer on perlite. 4. Wild plants were grew on uniform sand on different height of drain ditch. In this case, much more wild plants were grew on which had more higher drainage ditch. The number of wild plants occurred when it was affected by soil surface moisture, drain ditch and natural occurrence of wild plants. This could be controlled by layered soil at surface moisture. Therefore weed occurrence can control in planting ground, where soil layer would not be disturbed.

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강원지역의 산사태 위험지 분포 현황에 관한 연구 (The Study on the Status of Landslide Risk Region in Kangwon-Do)

  • 이승호;이민규;장범수;심정훈
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2005년도 춘계 학술발표회 논문집
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    • pp.846-853
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    • 2005
  • The whole death by disaster is totalized to 1,515 person from 1993 to 2004 year in our country. In this section life damages by landslide is totalized 357 people(about 24% of whole life damage). About 36 people are died by landslide(such as cutting area failure every year). Kangwon-do need a lot of interests and prevention because dangerous area that landslide occurrence is more than other area at summer localized downpour or thawing season and there is landslide occurrence possibility area more than other area. Kangwon-do area is higher than other area in natural disaster incidence and damage scale because topography and a lot of rainfalls by summer localized in Kangwon-Do than other area. In this study, dangerous area of landslide occurrence possibility is analyzed and compared Kangwon-Do with other areas in our country. as a result, every year we have experienced landslide occurrence and natural disaster. accordingly, we urgently need to prevent landslide occurrence and natural disaster by analy-zed source about landslide occurrence and condition of disaster in Kangwon-Do and suitable engineering method and construction work.

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Feedback scope for fault detection and localization

  • Hunsang Jung;Park, Youngjin
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2002년도 ICCAS
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    • pp.32.6-32
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    • 2002
  • The damage localization of the structural system using the natural frequency measurement only is proposed. The existing methods use the changes of mode shape, strain mode shape or curvature mode shape before and after the damage occurrence as these shapes carry the geometric information of the structure. Basically, the change of natural frequencies of the structure can be used as the indicator of the damage occurrence but not as the indicator of the damage location as the natural frequency changes does not carry the geometric information of the structure. In this research, the feedback scope method that measures the natural frequency changes of the structure with and without the feedback Ioo...

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Co-occurrence Patterns of Bird Species in the World

  • Kim, Young Min;Hong, Sungwon;Lee, Yu Seong;Oh, Ki Cheol;Kim, Gu Yeon;Joo, Gea-Jae
    • 생태와환경
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    • 제50권4호
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    • pp.478-482
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    • 2017
  • In order to identify key nations and bird species of conservation concern we described multinational collaborations as defined using network analysis linked by birds that are found in all nations in the network. We used network analysis to assess the patterns in bird occurrence for 10,422 bird inventories from 244 countries and territories. Nations that are important in multinational collaborations for bird conservation were assessed using the centrality measures, closeness and betweenness centrality. Countries important for the multinational collaboration of bird conservation were examined based on their centrality measures, which included closeness and betweenness centralities. Comparatively, the co-occurrence network was divided into four groups that reveal different biogeographical structures. A group with higher closeness centrality included countries in southern Africa and had the potential to affect species in many other countries. Birds in countries in Asia, Australia and the South Pacific that are important to the cohesiveness of the global network had a higher score of betweenness centrality. Countries that had higher numbers of bird species and more extensively distributed bird species had higher centrality scores; in these countries, birds may act as excellent indicators of trends in the co-occurrence bird network. For effective bird conservation in the world, much stronger coordination among countries is required. Bird co-occurrence patterns can provide a suitable and powerful framework for understanding the complexity of co-occurrence patterns and consequences for multinational collaborations on bird conservation.

Modeling the Natural Occurrence of Selected Dipterocarp Genera in Sarawak, Borneo

  • Teo, Stephen;Phua, Mui-How
    • Journal of Forest and Environmental Science
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    • 제28권3호
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    • pp.170-178
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    • 2012
  • Dipterocarps or Dipterocarpaceae is a commercially important timber producing and dominant keystone tree family in the rain forests of Borneo. Borneo's landscape is changing at an unprecedented rate in recent years which affects this important biodiversity. This paper attempts to model the natural occurrence (distribution including those areas with natural forests before being converted to other land uses as opposed to current distribution) of dipterocarp species in Sarawak which is important for forest biodiversity conservation and management. Local modeling method of Inverse Distance Weighting was compared with commonly used statistical method (Binary Logistic Regression) to build the best natural distribution models for three genera (12 species) of dipterocarps. Database of species occurrence data and pseudoabsence data were constructed and divided into two halves for model building and validation. For logistic regression modeling, climatic, topographical and edaphic parameters were used. Proxy variables were used to represent the parameters which were highly (p>0.75) correlated to avoid over-fitting. The results show that Inverse Distance Weighting produced the best and consistent prediction with an average accuracy of over 80%. This study demonstrates that local interpolation method can be used for the modeling of natural distribution of dipterocarp species. The Inverse Distance Weighted was proven a better method and the possible reasons are discussed.

Fusarium 곰팡이독소 T-2 독소와 HT-2 독소의 국.내외 연구동향 (Trends in Researches of Fusarium Mycotoxins, T-2 toxin and HT-2 toxin in Domestic and Foreign Countries)

  • 이수진;김미혜;오상석;전향숙
    • 한국식품위생안전성학회지
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    • 제27권1호
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    • pp.1-17
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    • 2012
  • T-2 toxin and HT-2 toxin, belong to type A trichothecences, are the most toxic mycotoxins among the trichothecene family. These mycotoxins are commonly found in cereals such as maize, wheat, barley, oats and rice, and their occurrence in food can be of concern. This review investigated the current trends of patents and researches on T-2 toxin and HT-2 toxin pertaining to natural occurrence, toxicity, metabolism, risk assessment, analytical and screening methods, and reduction/detoxification techniques. As compared with other $Fusarium$ mycotoxins, there are limited data for natural occurrence and risk assessment, and regulatory limit and official analytical methods on T-2 toxin and HT-2 toxin in domestic and foreign countries. In particular, selective deacetylation at the C3 and/or C4 positions of T-2 toxin by carboxyesterase present in foods was reported to cause the disappearance of T-2 and the extremely high HT-2 recoveries. Currently, regulatory limits for T-2 and HT-2 are under discussion in EU. For enforcement purposes it is essential to have available precise and reliable analytical methods applicable at the regulatory levels for the T-2 toxin and HT-2 toxin and relevant commodities. In addition, a further study on natural occurrence, risk assessment and reduction/detoxification techniques will be recommended.

매실나무에 기생하는 뽕나무깍지벌레 (Pseudaulacaspis pentagona)의 기주범위, 생활사 및 천적에 관한 조사 (Host range, Life cycle and Natural enemies of Mulberry scale (Pseudaulacaspis pentagona) on Prunus mume in south Korea)

  • 박종대;김규진
    • 한국응용곤충학회지
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    • 제29권2호
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    • pp.104-112
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    • 1990
  • 남부지방에서 뽕나무깍지벌레의 기주식물, 생활사 및 천적에 관하여 조사, 연구한 결과는 다음과 같다. 뽕나무깍지별레의 기주식물은 總 22科 74種이 조사되었으며 특히 Prunus層의 核果類에 피해가 많았다. 또한 本蟲은 연 3세대를 경과하며 유충 발생시기는 1세대가 5월 중순~6월 하순, 2세대 7월 중순~8월 중순, 3세대 9월 초순~10월 하순이었으며 최성기는 각각 6월 상순, 7월 하순, 9월 중순이었다. 난, 유충 및 雌成蟲의 개체군 밀도에 있어서는 최초 발생일로부터 각각 10일, 25일, 7일경에 가장 높았으며 뽕나무깍지벌레 천적은 Aphytis diaspidis, Archenomus orientalis, Apterencyrtus morophagus 등 기생봉 3種과 홍점박이무당벌레, 애홍점박이무당벌레, 무당벌레1種 등 3種의 포식충이 조사되었다. 뽕나무깍지벌레와 고약병균 감염은 신초신장과 및점한 관계가 있고 가해받지 않은 가지에 비해서 신초신장이 1/2, 1/4정도 밖에 이루어 지지 않았다.

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국내 소나무재선충병 발생 특성 분석: 2016~2018년 예찰데이터를 기반으로 (Analysis of Occurrence Characteristics of Pine Wilt Disease in Korea based on Monitoring Data from 2016 to 2018)

  • 심상택;이성희;이차영;남영우
    • 한국산림과학회지
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    • 제110권2호
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    • pp.280-288
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    • 2021
  • 소나무재선충병의 발생 특성을 이해하는 것은 소나무재선충병의 피해 및 확산을 최소화하기 위한 방제전략 수립을 위해 필수적이다. 따라서 본 연구에서는 기상 요인, 지리적 요인, 그리고 인위적 요인과 같은 환경 조건과 소나무재선충병 발생과의 관계를 분석하였다. 2016년 5월부터 2018년 4월까지 소나무재선충병 발생 자료와 자연적, 인위적 요인들을 포함한 다양한 환경 조건의 공간 자료들을 수집하였고, 소나무재선충병에 의한 고사목 발생 본 수에 대한 환경 변수들의 상대적 기여도를 평가하였다. 총 17개의 자연적 요인과 인위적 요인 중에서 소나무재선충병 발생에 영향을 미치는 요인들을 확인한 결과 자연적 요인은 고도와 5~8월 기온이, 인위적 요인은 도로와 건물과의 거리가 소나무재선충병 감염고사목 발생본수와 밀접하게 연관이 있는 것으로 나타났다.

재난발생과 자연적요인·사회적환경·풍수적요인간의 상관관계분석 (Analysis of Industry-related Relationships between Disasters, Natural Factors, Social Factors, and Feng Shui Factors)

  • 이정일
    • 대한안전경영과학회지
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    • 제25권4호
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    • pp.1-13
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    • 2023
  • This study aims to investigate the correlation between the causes of natural disasters and feng shui factors targeting disaster management experts, feng shui experts, and the general public who are interested in feng shui. To this end, it is intended to reveal that the factors of the disaster at Mt. The purpose of this study is to analyze the impact of three factors on disasters: feng shui factors, natural factors, and social factors. To this end, a survey was conducted targeting feng shui experts, disaster management experts, master's and doctoral students in feng shui geography, residents of the Umyeonsan disaster area, and people interested in feng shui geography. 260 copies of the questionnaire were prepared and 248 copies were used for the final analysis. First, in order to analyze the impact of feng shui factors on awareness of disaster occurrence, after controlling for demographic variables, hierarchical multiple regression analysis was conducted to analyze the impact of feng shui factors on awareness of disaster occurrence. Second, as a result of analyzing the effect of natural factors on awareness of disaster occurrence, looking at each independent variable in the second-stage regression analysis. Third, as a result of analyzing the effect of social factors on awareness of disaster occurrence, looking at each independent variable in the second-stage regression analysis. Finally, as a result of the T-test and Anova analysis conducted for discriminant analysis, if the p-value was less than .005, the F value for each group was obtained as a result of the ANOVA analysis on the feng-shui factors