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가뭄사상 및 농업수리시설물이 쌀 생산량에 미치는 영향에 대한 상관 분석
우승범 ( Woo¸ Seung-beom ),남원호 ( Nam¸ Won-ho ),전민기 ( Jeon¸ Min-gi ),윤동현 ( Yoon¸ Dong-hyun ),김태곤 ( Kim¸ Taegon ),성재훈 ( Sung¸ Jae-hoon ),김한중 ( Kim¸ Han-joong ) 한국농공학회 2021 한국농공학회논문집 Vol.63 No.5
Drought is a disaster that causes prolonged and wide scale damage. Recently, the severity and frequency of drought occurrences, and drought damage have been increased significantly due to climate change. As a result, a quantitative study of drought factors is needed to better understand and prevent future droughts. In the case of agricultural drought, several existing studies examine the economic damage caused by droughts and their causes, but these studies are not well suited to estimating crop-oriented agricultural drought damage and the factors that absolutely affect agricultural drought. This study determines which factors most affect agricultural drought. It examines meteorological factors and those related to agricultural water supplied by irrigation facilities. Rice paddy production per unit area is lower than the average from the last two years where agricultural drought occurred. We compare the relative frequency of agricultural drought impacts with irrigation facilities, effective reservoir storage, the number of water supply facilities, and the meteorological drought index such as Standardized Precipitation Index (SPI). To identify factors that affect agricultural drought, we correlate rice paddy production anomalies with irrigation water supply for the past two years. There was a high positive correlation between rice paddy production and irrigation water usage, and there was a low or moderate negative correlation between rice paddy production anomalies compared to the average of the past two years and SPI. As a result, agricultural water supply by irrigation facilities was judged to be more influential than meteorological factors in rice paddy production. This study is expected to help local governments establish policies related to agricultural drought response.
Fast Rate Adaptation for IEEE 802.11n WLAN
Seungbeom Lee,Jung-Hoon Lee,Sin-Chong Park 대한전자공학회 2007 ITC-CSCC :International Technical Conference on Ci Vol.2007 No.7
The 802.11n physical layer provides multiple transmission rates employing different modulation and coding schemes. The throughput performance of WLAN depends on the effectiveness of rate adaptation, based on how fast it can respond to the wireless channel variations. In this paper, we propose a Fast Rate Adaptation (FRA) algorithm for IEEE 802.11n WLAN and results of the proposed algorithm show a maximum 10% throughput improvement compared to the Collision-Aware Rate Adaptation (CARA) algorithm.
A Systematic Design Method of On-Glass Antennas Using Mesh-Grid Structures
Seungbeom Ahn,Hosung Choo IEEE 2010 IEEE Transactions on Vehicular Technology VT Vol.59 No.7
<P>In this paper, we propose a systematic design method for an on-glass antenna, which is suitable for receiving frequency modulation (FM) radio in a commercial recreational vehicle (RV). For the main antenna body, we used a mesh-grid structure that most efficiently uses the given space of the glass for broad-matching bandwidth. To obtain the detail design parameters that exhibit optimum radiating performance, we used a genetic algorithm (GA) in conjunction with a full-wave electromagnetic (EM) simulator. To reduce the searching space in our GA process, we applied a connection-warranted filtering. After the GA optimization, we also applied a shape-simplification process and a transparency-improvement process to broaden the passenger's field of view. The designed antenna shows an average gain of about -9.05 dBi along the bore-sight direction (θ = 90°, Φ = 270°) in the FM radio band (80-120 MHz), which is 10 dB higher than a commercial roof-mounted microantenna. Finally, the operating principle of the proposed antenna was examined by using a lumped-element circuit model, and these results confirmed that the proposed antenna is well suited for FM radio reception in commercial RVs.</P>
Diversity On-Glass Antennas for Maximized Channel Capacity for FM Radio Reception in Vehicles
Seungbeom Ahn,Yong Soo Cho,Hosung Choo IEEE 2011 IEEE transactions on antennas and propagation Vol.59 No.2
<P>This communication proposes a systematic design method to increase the diversity gain for vehicle on-glass antennas using the Pareto genetic algorithm. The initial antenna structure consists of two FM antennas printed on a rear window with horizontal conducting striplines. The position and the number of the vertical lines in the rear window were then determined using the Pareto genetic algorithm to maximize the channel capacity and average bore-sight gain of each antenna. The optimized antennas were built and mounted in a commercial sedan, and the antennas' performances, such as the reflection coefficient, radiation pattern, and channel capacity were measured. The measurements showed a matching bandwidth of around 15% and an average bore-sight gain of more than -12 dBi . The measured correlation coefficient of the two antennas was less than 0.6.</P>
The Evolution of Community Development Governance in Korean
Seungbeom Choi 서울행정학회 2003 서울행정학회 학술대회 발표논문집 Vol.- No.-
The purpose of the article is to analyze how a community has been developed since the Korean War in the area, where US Camp Humphreys is located. A collaborative relationship among local government, US camp, and residents is necessary for the town to prosper at peace with the camp. The relationship has changed basically by the environmental factors such as diplomatic policy, economic recession, political and social change, and military strategies. However, residents, businessmen, local government, central government and US camp have made a lot of efforts to develop their community, in which they have to live together. They have successfully made a cooperative relationship, though there were troubles in other US campsite villages in Korea. This study analyzes the evolutionary process of the community development from the perspective of the governance theory.