• 한국환경생태학회지
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• 제11권3호
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• pp.270-276
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• 1997

본 연구는 녹지 공간 확충과 입면녹화용으로 유용한 덩굴식물의 분포 특성을 알아보기 위하여 기존 식생자료를 토대로 덩굴식물의 수평 및 수직분포와 국내(남한) 자생 덩굴식물 종수 등에 관해 조사하였으며, 수직분포 조사지는 강원도의 설악산과 어답산, 겨익도의 광교산, 전라남북도와 경상남도에 걸쳐있는 지리산을 대상으로 식생자료를 검색하였다. 연구결과를 요약해보면 다음과 같다. 남한지역에 분포하는 덩굴식물 종류는 총 41과 95속 267종 이었고, 덩굴식물의 수평분포 특성은 위도가 낮아질수록 출현종수가 증가하였으며 고산지대와 북한지역의 북부지방을 제외한 우리나라의 거의 전지역이 덩굴식물 생육에 적당하다고 사료되었다. 또 덩굴식물의 수직분포 특성은 표고가 높아질수록 현저히 감소하였고 해발 1,500m이상에서는 거의 나타나지 않았는데 이러한 지역의 온량지수는 45이하에 해당되며, 동일한 고도라 하더라도 지지체가 되는 식물 군락의 종류에 따라 출현하는 덩굴식물의 종류는 상이하였다. 사면별로 덩굴식물의 출현종수에 차이가 있었으며, 남사면이 북사면에 비해 종다야성은 낮은 경향을 보였다.

• 한국공간구조학회논문집
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• 제2권1호
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• pp.85-92
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• 2002

Two way grid single-layer domes are of great advantage in fabrication and construction because of the simple fact that they have only four members at each junction. But, from a point of view of mechanics, the rectangular latticed pattern gives rise to a nonuniform rigidity-distribution in the circumferential direction. If the equivalent rigidity is considered in the axial direction of members, the in-plane equivalent shearing rigidity depends only on the in-plane bending rigidity of members and its value is very small in comparison to that of the in-plane equivalent stretching rigidity. It has a tendency to decrease buckling -strength of dome considerably by external force. But it is possible to increase buckling strength by the use of roofing covering materials connected to framework. In a case like this, shearing rigidity of roofing material increases buckling strength of the overall structure and can be designed economically from the viewpoint of practice. Therefore, the purpose of this paper, in Lamella dome and rectangular latticed dome that are a set of 2-way grid dome, is to clarify the effects of roofing covering materials for increasing of buckling strength of overall dome. Analysis method is based on FEM dealing with the geometrically nonlinear deflection problems. The conclusion were given as follows: 1. In case of Lamella domes which have nearly equal rigidity in the direction of circumference, the rigidity of roofing covering materials does not have a great influence on buckling-strength, but in rectangular latticed domes that has a clear periodicity of rigidity, the value of its buckling strength has a tendency to increase considerably with increasing rigidity of roofing covering materials 2. In case of rectangular latticed domes, as rise-span-ratio increases, models which is subjected to pressure -type-uniform loading than vertical-type-uniform loading are higher in the aspects of the increasing rate of buckling- strength according to the rate of shear reinforcement rigidity, but in case of Lamella dome, the condition of loading and rise-span-ratio do not have a great influence on the increasing rate of buckling strength according to the rate of shear reinforcement rigidity.

• 한국태양에너지학회 논문집
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• 제36권4호
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• pp.11-20
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• 2016

For accurate wind resource assessment and wind turbine performance test, it is essential to secure wind data covering a rotor plane of wind turbine including a hub height. In general, we can depict wind speed profile by extrapolating or interpolating the wind speed data measured from a meteorological tower where multiple anemometers are mounted at different heights using a power-law of wind speed profile. The most important parameter of a power-law equation is a vertical wind profile exponent which represents local characteristics of terrain and land cover. In this study, we calculated diurnal vertical wind profile exponents of 8 locations in Jeju Island who possesses excellent wind resource according to the GUM (Guide to the Expression of Uncertainty in Measurement) to evaluate its uncertainty. Expanded uncertainty is calculated by combined standard uncertainty, which is the result of composing type A standard uncertainty with type B standard uncertainty. Although pooled standard deviation should be considered to derive type A uncertainty, we used the standard deviation of vertical wind profile exponent of each day avoiding the difficult of uncertainty evaluation of diurnal wind profile variation. It is anticipated that the evaluated uncertainties of diurnal vertical wind profile exponents at 8 locations in Jeju Island are to be registered as a national standard reference data and widely used in the relevant areas.

• Journal of electromagnetic engineering and science
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• 제15권1호
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• pp.6-13
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• 2015

In this paper, a novel monopole antenna for WLAN/WiMAX application is presented. The proposed antenna consists of two arc-shaped strips, a vertical strip, and a slot in the ground plane. In this study, a prototype of the proposed triple-band antenna was designed, fabricated, and tested. The quantitative and experimental results demonstrate that the proposed antenna satisfy the -10 dB impedance bandwidth requirement of 440 MHz for 2.4/2.5 GHz bands (from 2.26 to 2.70 GHz), 970 MHz for 3.5 GHz bands (from 3.27 to 4.24 GHz), and 870 MHz for the GHz bands (from 5.08 to 5.95 GHz), while simultaneously covering the WLAN and WiMAX bands. In addition, the presented triple-band antenna has an omnidirectional radiation pattern at all three frequency bands with an antenna gain of 4.45 dBi for the lowest band, 2.04 dBi for the middle band, and 3.98 dBi for the highest band.