• The Korean Journal of Ecology
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• 제12권3호
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• pp.171-182
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• 1989

The structure, clonal grwoth, shoot modules dynamics and rhizome respiratory rate of the Phragmites longivalvis circular patch were studied in a 15-year-old reclaimed land on Mado of the western Korea for two growing seasons. Clonal growth by P. longivalvis resulted in subpopulations of shoot modules which may be separated into pioneer, mature and senile growth phase. The radial growth of circular patch was 208 cm per a year. The shoot phytomass, shoot height and spike frequency were the lowest in the senile phase, and were the highest in the mature phase. The maximum shoot phytomass of pioneer, mature and senile phase in August was 347, 536 and 195g/$\m^2$ for the first year, and 609, 748 and 248g/$\m^2$ for the second year, respectively. The birth rates of shoot modules were the highest during the early spring. Of all modules, the percemtage of spring cohort of pioneer, mature and senile growth phase were 52, 82 and 70% for the first year, and 83, 88 and 85% for the second year, respectively. The flowering shoots were only derived from spring cohorts. The death rates of shoot modules of the pioneer and mature phase were the highest in October. The module is an annual semelparous plant though the genet is a perennial iteroparous plant. Their survivorship curve was negatively (Deevey type I). The density of shoot modules of the pioneer, mature and senile growth phase increased as much as 4.0, 1.6 and 2.3 times for one year, respectively. The respiratory rate was the highest in the lowest in the senile growth phase.

• 한국위성정보통신학회논문지
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• 제5권2호
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• pp.50-56
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• 2010

이제까지 수행된 우주 탐사 임무에서 임무 궤도의 설계는 행성 혹은 위성과 인공위성의 2체 문제 (two-body problem)에 기초한 Hohmann transfer를 기반으로 하는 Patched Conic Approximation 방식이 주로 사용되어져 왔다. Hohmann transfer는 원 궤도에서 다른 원 궤도로 천이할 수 있는 타원 천이 궤도의 설계 방식으로서, Patched Conic Approximation은 태양계를 여러 개의 2체 문제로 분해하고 각기 분해된 2체 시스템 사이의 Hohmann 천이 궤도를 설계하여 조합함으로써 행성 간의 임무 궤도를 설계하는 방식이다. 이 방식은 하나의 행성만을 고려했을 때, 즉 행성과 인공위성의 2체 문제일 때, 가장 효율적인 천이 방식으로 알려져 있고 현재까지의 우주 탐사 임무 설계에 주로 이용되고 있다. 하지만, 우주 탐사 임무가 점차 다양화되고 소형 위성을 이용한 임무 수행의 필요성이 증가함에 따라 기존의 Patched Conic Approximation은 요구되는 연료의 양이 크다는 점과 원뿔꼴(conic) 특성을 가지는 궤도만을 표현할 수 있다는 점에서 한계점을 보이기 시작하고 있다. 이에 반해 3체 동역학의 기하학적 특성은 기존의 태양계의 패러다임을 획기적으로 변화시킨다. 개념적으로는 요구되는 에너지가 매우 적은 에너지로 태양계를 모두 연결하는 궤도를 구성할 수 있기 때문이다. 본 논문에서는2체문제 기반의 임무 궤도 설계 기술의 한계성에서 벗어나 유연하고 효율적인 탐사 임무를 설계한다.

• 한국조경학회지
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• 제32권6호
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• pp.14-22
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• 2005

The purpose of this paper is to assess conservation value of forests and cultivated areas from the landscape ecological point of view. The main focus of landscape ecology estimates the reciprocal relationships between spatial patterns and ecological processes. This paper sets the criteria for conservation value and classify the conservation value based on the criteria. Forests and cultivated areas in Seo-Gu, Incheon Metropolitan City was selected as the case study area. In this research, factors such as patch size and connectivity have been selected in order to consider the landscape ecological aspect, gradient for the environmental physics aspect and to consider the environment-ecological aspect, grade of environmental-oriented land suitability analysis Map developed by the ROK Ministry of Environment has been utilized. GIS methodologies have been adopted to calculate the relationships among the above variables. Through literature review, the following evaluation criteria have been adopted: (1) based on island biogeography and metapopulation dynamics theory, patch size criteria are set 2ha and 10ha; (2) connectivity was set the degree of connection with surrounding grids; and (3) gradient of 20 degrees. Conclusively, this paper suggests that local conditions, landscape ecology and physical environment aspects should be considered to develop an estimation framework of the conservation value.

• The Korean Journal of Ecology
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• 제21권5_3호
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• pp.649-663
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• 1998

The clarify the ecological properties, and to predict change of understory vegetation of mt. Nam Park, population dynamics and interspecific competition of D. smilacinum and D. viridescens, which grow in understory of deciduous broad-leaved forest and pseudo-annuals, were studied from May 20 to May 30 1998. The depth of litter layer, soil moisture content, soil organic matter and soil texture were surveyed in 18 populations (15 D. smilacinum populations and 3 D. viridescens populations). Mean litter layer of d. smilacimum population was thinner than that of D. viridescens populations). Mean litter layer of D. smilacnum population was thinner than that of D. viridescens population. The contents of soil moisture and organic matter of D. smilacinum population were lower than that of D. viridescens population. The D. smilacinum growed in broad range of soil texture but D. viridescens in loamy soil. Because D. smilacinum could tolerate more broad range of soil moisture and soil texture than D. viridescens, the former covered the herb layer in earlier stage and the latter introduced in later stage when rhizome could grow easily. The numbers of individual in two marginal parts were smaller than that in center in same D. smilacinum patch. And the total numbers of individuals grown in (10 ${\times}$ 10)cm were from 0 to 12. The rhizome (subterranean runner) weight, rhizome length, root weight, shoot weight, lea weight and leaf number per subquadrat (cell) increased along the number of individual, that is, increased from marginal part to center. But rhizome weight and rhizome length per individual were vice versa. Therefore, the individuals in marginal part reproduced longer and stronger asexual propagules than that in center. The distribution pattern of D. smilacinum was contageous and that of D. viridescens was random or regular. Therefore, population growth of former was independent on density and that of latter was dependent on density. The distributions of size-class showed normal curves in two population, but the curves based on data of total dry weight showed positive skewness and those of leaf number showed negative skewness The correlation coefficient (CC) values between the properties of each organ were high in two population and significant at 0.1% level. The CC values of D. viridescens were higher of the two. Therefore, the former allocated the energy to each organ stable. The rhizome depth of d. viridescens was 2 times deeper than that of D. smilacinum. And rhizome length and weight of D. viridescens were longer (2 times) or heavier (4 times) than those of D. smilacinum. The patch size of D. viridescens increased 60 cm per year and that of D. smilacinum 30 cm. On this results, the intrinsic increase velocity of d. viridescens patch was 2 times faster than that of d. smilacinum, therefore, on the competition, the former had an advantage over D. smilacinum. The reason why d. viridescens defeated D. smilacinum resulted from that the leaf area of former was 4 times broader than that of latter. in Mt. Nam Park, it was thought that two disporum Population would change with the 3 thpes of environmental change as followings. First, no human impact and increase of soil moisture content resulted in increase of D. viridescens population. Second, mild human impact and similar condition of soil moisture content resulted in slow increase or no changes of D. smilacinum and d. viridescens population. Third, severe human impact and dry condition resulted in decrease or vanishment of two disporum populations.

• Composites Research
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• 제36권2호
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• pp.108-116
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• 2023

본 논문에서는 복합재료로 제작된 구조물의 유지보수 자동화를 위한 소형 매니퓰레이터 플랫폼 개발을 위해 기구학적 설계와 다물체 동역학 해석을 수행하였다. 매니퓰레이터의 기구학적 설계를 수행하기 위해 기존복합재 보수 공정을 고려하였다. 보수용 패치 적층 공정을 고려하여 매니퓰레이터와 엔드 이펙터의 기본 제원을 선정한 뒤 3-D 설계를 수행하였다. 이후 보수공정을 고려한 역기구학 해석을 통해 시뮬레이션 및 제어에 필요한 변수를 MATLAB에서 생성하였다. 플랫폼의 구조안정성 평가를 위해 Altair Inspire와 Optistruct를 통한 다물체 동역학 해석을 수행하였다. Inspire에서 진행된 시뮬레이션을 기반으로 Optistruct에서 다물체 동역학 해석을 수행한 뒤 시간에 따른 최대 변위와 Von-Mises 응력 결과를 통해 구조안정성을 검증하였다. 설계검증을 위해 플랫폼의 실제 제작 및 제어를 수행하여 시뮬레이션과 비교한 결과, 실제 보수과정 경로와 시뮬레이션이 잘 일치하는 것을 확인하였다.

• 한국응용곤충학회지
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• 제49권4호
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• pp.289-297
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• 2010

세계적으로 인간 활동 따른 서식지의 소실과 단절은 생물다양성을 떨어뜨리는 주요원인이며 서식지의 소형화와 세분화는 개체군의 크기를 감소시키고 있다. 본 연구는 꼬리명주나비를 표지-방사-재포획법(MRR 방법)을 이용하여 메타개체군 동태를 파악하였다. 그 결과 2,749 개체(암컷-2295, 수컷-454)가 포획되었으며 이중 343개체(12.8%)가 재포획되었다. 포획된 암수 비율에서는 수컷이 주를 이루는 것으로 나타났다. Jolly-Seber의 방법으로 일일메타개체군의 크기, 생존율, 추가율, 사망률을 추정하였다. 저자들은 보전생물학자들에게 단절된 경관에서 국지적 메타개체군의 관리와 보전을 강조하고자 하며, 특히 한국산 꼬리명주나비의 경우 지속적인 서식지 보전이 필요하다.

• 환경생물
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• 제23권2호
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• pp.141-145
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• 2005

본 연구는 전나무림 생태계 이해를 위하여 전나무 임분구조에 관한 기초자료를 수집하는 조사의 일부이다. Leibundgut(1981)의 임분구조 분류에 따르면 A,B임분은 쇠퇴기로 추정되며 C는 갱신기, D는 안정기와 쇠퇴기 복합형, E는 불안정한 시기인 택벌상으로 추정된다.

• 천문학회보
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• 제44권2호
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• pp.70.3-70.3
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• 2019

We present a method to estimate 3-component plasma velocity (Vx, Vy and Vz) at solar photosphere near solar disk center, using the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO) called Space-weather HMI Active Region Patch (SHARP). In Heliocentric-Cartesian Coordinates, the component of Vz is obtained from Dopplergram while the components of Vx and Vy are derived from the relation of $B_z{\overrightarrow{u}}=B_z{\overrightarrow{{\nu}_t}}-{\nu}_z{\overrightarrow{B_t}}$ (Demoulin & Berger 2003) using a series of vector magnetograms by an optical flow technique NAVE (Nonlinear Affine Velocity Estimator). This velocity measurement method is applied to AR 12158 producing an X1.6 flare along with a coronal mass ejection. We find noticeable upflow motions at both ends of flux ropes which become a major eruption part, and strong transverse motions nearby them before the eruption. We will discuss the change of plasma motions and magnetic fields before and after the eruption.

• 한국조경학회지
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• 제36권1호
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• pp.62-69
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• 2008

This study was conducted in order to recommend forest-based wildlife protection areas in Chung-nam Province using several basic habitat conditions. The conditions used in this study were the forest patch size with the potential to keep wildlife animals safe, the distance from water sources, and the availability of food for wildlife. The fractal dimension index was also used to find the edge line dynamics, which can influence on habitat conditions for edge species. The natural conservation management indices including a forest map (indicating the level of forest age), a slope map, and an elevation map were used to find the forest patches with enough space for wildlife to live on. Water resources and their buffer areas were considered as factors to protect the space as an ecological corridor. Deciduous trees and trees mixed with deciduous trees and conifers were chosen to provide wildlife animals their food. In total, 525 forest patches were chosen and recommended for the wildlife protection area. Five of these forest patches were recommended as wildlife protection areas managed by the provincial government. The other 520 forest patches were recommended to protect local wildlife animals and be managed by each county or city. These forest patches were located around the Geum-buk and Geum-nam mountains, and the forest patches are important resources as habitats to keep wildlife in the area. An ecological network consists of these separate forest patches with the ecological integration. A fractal dimension index was used to divide forest patches into several categories in order to find how patches are shaped. The forest patches with longer edges or more irregular shapes have a much higher possibility of being inhabited by various types of edge species. Through comparison of the wildlife protection areas recommended in this study to the current wildlife protection areas, we recognized that the current wildlife protection areas need boundary adjustments in order for wildlife animals to survive by themselves with water sources and food.

• 한국환경복원기술학회지
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• 제4권2호
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• pp.52-61
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• 2001

At least, there are intense pressures on the natural habitats from various disturbance, including urbanization, extension of industrial area, and road construction. These human land use result in fragmentation of landscape and natural habitat. The ecological consequences of habitat fragmentation include the direct effects of habitat loss and the indirect effects of reduced inter-patch dispersal. The decline of biological diversity has been rapidly declined by the habitat loss and fragmentation. Conservation strategists should consider not only the habitat amount of that must be preserved, but also the spatial configuration of habitat across the landscape. But, the paucity of available data for most species forces landscape ecologists to develop the concept, model, and theory. The developed theories are often misused in academic papers and practical applications. The development history, presumption of concept, model, theory is ignored. This tendency have leaded to failure of landscape restoration and the use of theory in conservation practice have come under increasing attacks. This paper will highlight the ecological theory that have proven the most influential in landscape ecology, restoration and conservation : the theory of island biogeography, the theory of nested subset analysis, minimum viable population(MVP), the theory of metapopulation dynamics. And, it find the problem and usefulness of four theory in application to real world. Consequently, the understanding of theoretical implication about landscape ecological theory is required. We must carefully apply the theory after examining the problem and availability of various theory because of no existence of only one general theory.