• Title/Summary/Keyword: 천이계열

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Environmental Studies Of The Jinhae Bay 3. Ecological Succession Of Phytoplankton Populations, 1974~1980

  • Yoo, Kwang Il;Lee, Jin Hwan
    • 한국해양학회지
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    • v.15 no.2
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    • pp.100-107
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    • 1980
  • 1974년 9월부터 1980년 1월까지 6년간 진해만에서 식물성플랑크톤 개체군의 생태적 천이에 관하여 조사하였다. 1974년 9월∼1975년 5월에는 천이계열이 Skeletonema costatum-Eucampia zodiacus Chaetoceros spp.-Nitzschia pungens- Leptocylindrus danicus, 1976년 7월-1978년 5월 Skeletonema costatum-Thalassiosira hyalina- Chaetoceros spp. -Leptocylindrus danicus(Nitzschia pungens), 1978년 7월-1980년 1월 Chaetoceros socialis-Skeletonema costatum-Chaetoceros spp. -Leptocylindrus danicus-Skeletonema costatum(Biddulphia mobiliensis)으로 천이계열이 바뀌어가고 있으며 이들은 계절에 따라 수온의 변화와 밀접한 관계가 있었다. 최근에는 이 해역에서 Skeletonema costatum이 계절에 관계없이 대량출현하여 이 종에 의해 점점 성숙한 천이계열을 형성해 가고 있다.

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Analysis of Random Sequences using Nonlinear Combining Functions (비선형 합성 함수를 이용한 랜덤 계열의 특성 분석)

  • 염흥열
    • Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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    • 1994.11a
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    • pp.132-156
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    • 1994
  • 본 논문에서는 비선형 합성 함수를 이용하여 생성된 난수 계열의 특성을 분석한다. 먼저 트레이스 함수 등을 정의하고, 선형 복잡도 및 생성기 구조 분석시 요구되는 관련 이론을 도출하고, 특정 난수 계열이 주어진 경우 이계열을 생성할 수 있는 최소 길이의 LFSR을 합성할 수 있는 USR 합성 알고리듬을 제시한다. 동일한 계열을 위상 천이한 계열간의 비선형 결합으로 생성된 난수 계열과 다른 계열간의 비선형 결합으로 생성된 난수 계열에 대한 주기 및 선형 복잡도 등의 특성을 분석하고 생성기의 구조를 제시한다.

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Changes of Vegetation Structure according to the Hydro-seral Stages in the East Coastal Lagoons, Korea (동해안 석호에서 수생천이계열에 따른 식생구조의 변화)

  • Kim, Hyoe-Young;Kim, Mi-Hee;Choi, Hee-Kyung;Lyang, Doo-Yong;Shin, Eun-Joo;Lee, Kyu-Song;Yi, Hoon-Bok
    • Journal of Wetlands Research
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    • v.12 no.3
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    • pp.129-144
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    • 2010
  • We have studied the changes of the environmental and vegetational factors according to the hydro-seral stages in the shoreline of the lagoons, Korea. We have divided seral stages into 7 stages from open water stage to the stratified forest stage considering as the characteristics of water body, dominance of submerged and emergent plant, and development of the shrub, subtree and tree layer. According to the successional stage, water depth gradually decreased and water quality changed from seawater to brackish water and from brackish water to fresh water, organic matter in a soil layer gradually increased, and the litter layer grew up. As the development of the vegetation structure, the life-form of the vascular plants changed as follows; open water ${\rightarrow}$ submerged plant and floating-leaved plant ${\rightarrow}$ emergent plant and submerged plant ${\rightarrow}$ emergent plant ${\rightarrow}$ emergent plant, mesophyte and scrub ${\rightarrow}$ mesophyte. In the late seral stage, the 3 different forest types were established by the water retention or drainage and nutrient accumulation of the soil layer. Salix dominant forest developed in the wetted sites, the forest type dominated by Pinus thunbergii, Carex pumila and mesophytes developed in the well drained sites causing by sand substrate, and the forest type dominated by the planted or ruderals such as Pinus densiflora, Robinia psedo-acacia, Festuca ovina, Setaria viridis ect. developed in the sites composed of forest soil introduced by artificial reclamation.

Plant Community Structure of Chuwang Valley in Chuwangsan National Park (주왕산국립공원 주왕계곡의 식물군집구조)

  • 이경재;조재창;강현경
    • Korean Journal of Environment and Ecology
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    • v.8 no.2
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    • pp.107-120
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    • 1995
  • To investigate the forest structure of Chuwang valley of Chuwangsan National Park, thirty plots were set up and surveyed. Importance values, DBH class distribution, species diversity indices, DCA Ordination, CCA ordiantion and TWINSPAN classification were used for vegetational structure analysis. Pinus densiflora Quercus serata, Q. mongolica, Q. variabilis were appeared to be dominant species in thirty plots. According to the analysis of classification by TWINSPAN, the thirty plots divided four groups. Groups were Q. mongolica-P. densiflora-Carpinus laxiflora community(I), P. densiflora-Q. variabilis community(II), Q. serrata-Q. variabilis community(III), broad-leaved mixed community(IV) Species diversity(H') of investigated area was calculated 1.17~l.32. The successional trend was seemed to be from P. densiflora to Q. spp. in the canopy layer.

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Plant Community Structure of Warm Temperate Evergreen Broad-Leaved Forest in Hongdo, Korea (홍도 상록활엽수림 지역의 식물군집구조)

  • Oh, Koo-Kyoon;Cho, Woo
    • Korean Journal of Environment and Ecology
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    • v.8 no.1
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    • pp.27-42
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    • 1994
  • Vegetational structure and successional sere were investigated for evergreen broad-leaved forest in Hongdo. Forty-nine plots were classified into six groups, which are Camellea japonica community, Machilus thunbergii community, Castanopsis cuspidata var. sieboldii-Machilus thunbergii community, Castanopsis cuspidata var. sieboldii community, Castanopsis cuspidata var. sieboidii-Camellea japonica community and evergreen broad-leaved mixed community by the DCA ordiantion and TWINSPAN techniques. Successional sere of the forest vegetation in the surveyed area were proceeding from Pinus densiflora through Castanopsis cuspidata var. sieholdii to Neolitsea sericea, Dendropanax morbifera, Machilus japonica, Quercus acuta and Mahilus thunbergii in the canopy layer group and from Ligustrum japonicum, Ardisia japonica. Eurya japonica. Rhaphiolepsis umbellata through Trachelosperum asiaticum, Kadsura japonica. Litsia Japonica, Camellea japonica to Aucuba japonica, Euscaphis japonica, Ficus erecta in the understory and shrub layer group.

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Analysis of Oscillatory Behaviors in Shock Waves and Development of M-AUSMPW+ (충격파에서의 물성치 진동현상에 대한 분석과 M-AUSMPW+ 수치기법 개발)

  • Kim,Gyu-Hong;Lee,Gyeong-Tae;Kim,Jong-Am;No,O-Hyeon
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.30 no.2
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    • pp.21-29
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    • 2002
  • The M-AUSMPW+ scheme that can capture shock waves exactly with monotonic characteristic is developed by analyzing the cause of oscillation in shock regions. Firstly shock-capturing characteristics of general FVS including the AUSM-type schemes are investigated in detail, according to the different between a cell-interface and a sonic transition position. The cause of oscillation is the improper numerical dissipation that could not represent the real physics. The M-AUSMPW+ could capture shocks exactly without oscillatory behaviors in considering the sonic transition position and an cell-interface position

Early Vegetation Succession in Abandoned Field in Cheju Island (제주도 저지대 묵밭 식물군락의 2차 천이)

  • 유영한;이창석
    • The Korean Journal of Ecology
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    • v.26 no.4
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    • pp.209-214
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    • 2003
  • In order to clarify the successional trend and its characteristics of plant community in abandoned field in Cheju Island, we investigated the seral changes of vegetation height, coverage, growth form, species richness, diversity and dominance index along with the time lapse, and then compared with those of mainland researches. And in order to seek the overall trend of vegetation changes, we used cluster, TWINSPAN and PCA ordination techniques. The succession was characterized by the lower species number, lower vegetation height, longer period of herb dominant and later invasion of tree species. These results may come from that ecological traits of Cheju Island itself, and ecosystem fragmented influences that block a seed (propagule) transport. Sere of the dominant species was shown as follows: Mazus japonicus(0.5∼1 years)→Conyza sumatrensis (2 years)→Artemisia princeps var. orientalis(4 years)→Artemisia princeps var. orientalis, indigofera pseudotinctoria(5 years)→Rosa multiflora, Miscanthus sinensis, etc.(8 years)→Miscanthus sinensis(12 years)→Boehmeria nivea, Pueraria thunbergiana etc.(15 years)→Mallotus japonicus(20 years)→Litsea japonica, Machilus thunbergii (20 years<). Abandoned fields were classified into three groups according to time lapse; earlier stage(0∼1 years), middle stage(2∼8 years) and later stage(8∼20 years).