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가리왕산 일대 천연활엽수림에서 Cluster분석법에 의한 산림군집 분류에 관한 연구
정상훈 ( Sang Hoon Chung ),임선미 ( Seon Mi Lim ),양희문 ( Hee Moon Yang ),성주한 ( Joo Han Sung ),김지홍 ( Ji Hong Kim ) 한국임학회 2014 산림과학 공동학술대회 논문집 Vol.2014 No.-
본 연구는 가리왕산 일대 동부지방산림청 평창관리소 관내 국유 천연활엽수림의 과학적인 산림경영관리와 합리적인 보전을 달성하는데 기초적인 작업으로서 군집분류를 수행하기 위하여 실시하였다. 무작위로 설치한 112개의 정방형 (20 m × 20 m) 표본구에서 수집한 식생자료를 바탕으로 다양하고 복잡한 천연림을 몇 개의 공통된 식생 그룹으로 묶어주는 시도로서 cluster분석법을 이용하였다. 분류된 각각의 군집별로 수종 구성을 파악하였다. 또한 일반적인 생태 정보를 획득하기 위하여 각각의 군집별로 지형적 위치 분포 양상과 고도별 분포 정도를 조사하였다. 연구 대상 산림은 상층의 우점 수종이 대표성을 띠는 5개의 군집 즉, 신갈나무군집, 신갈나무-들메나무-물푸레나무군집, 박달나무-신갈나무군집, 중생혼효림군집, 거제수나무-난티나무군집으로 분류되었다. 각 군집별로 수종 구성 비율이 상당히 다르게 산출되었는데, 주로 군집 이름에 붙여진 수종을 중심으로 우점 비율이 높게 나타났다. 각 군집별로, 능선, 산복, 계곡 등의 지형적 위치 분포 양상과 고도별 분포 정도는 우점 수종들이 선호하는 입지요구도를 반영하는 경향이 있었다. The study was carried out to classify the forest communities in the natural deciduous forest of Gariwangsan area, part of the national forest. The cluster analysis was used to make diversified complex natural forest be several common groups on the basis of the vegetation data from randomly established 112 square sample plots (20 m × 20 m). The species composition for each classified community was examined. And the distribution pattern of topographic position and average elevation for each community were surveyed to grasp general ecological information. The study forest was classified into 5 forest communities. They were Quercus mongolica community, Q. mongolica - Fraxinus mandshurica - Fraxinus rhynchophylla community, Betula schmidtii - Qercus mongolica community, Mixed mesophytic community, and Betula costata - Ulmus laciniata community. The ratio of species composition was varied by community types, showing different dominant overstory tree species in each community. The distribution pattern of topographic position and elevation by community types tended to reflect the site requirement of dominant tree species.
광대역 컨포멀 배열 안테나를 위한 빔 형성 연구 및 최적 소자 위치 선정
정상훈(Sang-Hoon Jung),이강인(Kang-In Lee),남상욱(Sang-Wook Nam),정용식(Young-Seek Chung),윤영중(Young-Joong Yoon),유홍균(Hong-Kyun Ryu),정현교(Hyun-Kyo Jung) 한국전자파학회 2016 한국전자파학회논문지 Vol.27 No.2
본 논문에서는 LSM(Least Squares Method)와 GA(Genetic Algorithm)를 이용한 광대역 컨포멀 배열 안테나의 최적 빔형성을 제안하였다. LSM을 적용하여 컨포멀 배열 안테나의 빔 패턴을 선형 배열 안테나의 빔 패턴으로 근사시키는 가중치들을 구하였다. 그리고 GA를 이용하여 광대역에서 최적의 빔 패턴을 형성하는 컨포멀 배열 안테나의 최적 위치들을 구하였다. 제안된 방법을 검증하기 위해 Bezier 플랫폼 배열 안테나에 적용시켜 보았다. This paper proposes an optimum beam forming of conformal array antenna by using LSM(Least Squares Method) and GA(Genetic Algorithm). The weights which approximate conformal array antenna beam pattern to linear array antenna beam pattern have been evaluated by applying LSM. Also, the optimum locations of conformal array antenna which form wideband optimum beam pattern have been obtained by using GA. The proposed method is applied to a problem of Bezier platform array antenna for a verification purpose.
Moving Least Squares 기법을 이용한 광대역 컨포멀 빔 형성 연구
정상훈(Sang-Hoon Jung),이강인(Kang-In Lee),정현교(Hyun-Kyo Jung),정용식(Young-Seek Chung) 대한전기학회 2019 전기학회논문지 Vol.68 No.1
In this paper, beam forming using moving least squares method (MLSM) is studied. In the previous research, the least squares method (LSM), one of the data interpolation methods, was used to determine the desired beam pattern and obtain a beam pattern that minimizes the square of the error with the desired beam pattern. However, LSM has a disadvantage in that the beam pattern can not be formed to satisfy the exact steering angle of the desired beam pattern and the peak sidelobe level (PSLL) condition. To overcome this drawback, MLSM is used for beam forming. In order to verify, the proposed method is applied in beam forming of Bezier platform array antenna which is one of conformal array antenna platform
정상훈 ( Sang Hoon Chung ),황광모 ( Kwang Mo Hwang ),성주한 ( Joo Han Sung ),김지홍 ( Ji Hong Kim ) 한국산림과학회 2015 한국산림과학회지 Vol.104 No.3
We classified the forest type and figured out the ecological characteristics for each of the types in order to provide the basic informations for being induced ecologically efficient forest practice plan by vegetation units in the natural forest of Songnisan. We established the 250 sample points and collected the vegetation data of vertical distribution for each sample. A variety of multivariate statistical methods were applied to classify the forest types. The species diversity index were analyzed to estimate the stability and maturity for forest vegetation in each the type. The types were divided from two to ten clusters by cluster analysis. The appropriate number of clusters was estimated five clusters by indicator species analysis. It was verified through the multiple discriminant analysis that the estimated number of clusters had been suitable. Based on the species composition for each the type, this study site was classified into five forest types: 1) Quercus serrata and 2) mixed mesophytic forest in the valley area, 3) Q. mongolica forest in the main ridge, 4) Pinus densiflora forest in the sub-ridge extending from the main, and 5) Q. variabilis-P. densiflora forest between the sub-ridge and valley. The species diversity index of the pine forest that had been a simple species composition was the lowest while that of the mixed mesophytic forest of which the composition had been diverse was the highest. As the forest vegetation was more varied, the index showed a tendency to increase.
축소-확대 유로에 적용한 횡류형 수직 풍력발전시스템의 개발
정상훈(Sang-Hoon Chung),정광섭(Kwang-Seop Chung),김철호(Chul-Ho Kim) 대한설비공학회 2011 설비공학 논문집 Vol.23 No.8
New concept of wind energy conversion system is proposed to increase the energy density at a given working space. The quality of wind for wind power generation is depend on its direction and speed. However, the quality is not good on land because wind direction is changeable all the time and the speed as well. The most popularly operated wind turbine system is an axial-flow free turbine. But its conversion efficiency is less than 30% and even less than 20% considering the operating time. In this research, a cross-flow type wind turbine system is proposed with a convergent-divergent duct system to accelerate the low speed wind at the inlet of the wind turbine. Inlet guide vane is also introduced to the wind turbine system to have continuous power generation under the change of wind direction. In here, the availability of wind energy generation is evaluated with the change of the size of the inlet guide vane and the optimum geometry of the turbine impeller blade was found for the innovative wind power generation system.