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지하철 터널 형태에 따른 2.4GHz 대역 무선영상 신호의 페이딩 특성
송기홍,Song, Ki-Hong 한국정보통신학회 2008 한국정보통신학회논문지 Vol.12 No.2
본 논문에서는 지하철용 2.4GHz대 무선영상 전송 신호의 신호 성능을 파악하기 위하여 신호 변화 현상이 크게 발생하는 지하철역 플랫폼을 중심으로 신호 레벨을 측정하여 지하철 역 내부 구조에 따른 페이딩 특성을 분석한다. 측정 결과에 대한 분석 결과, 직선역 구간에서 다수의 강한 다중경로파가 생성되어 곡선역 구간에 비해 신호 레벨의 변화가 심하게 나타났다. 경로손실 지수는 직선역 구간인 신흥역에서 2.5, 곡선역 구간인 판암역과 대동역에서는 각각 1.6와 1.9으로 나타났다. 50% 지점의 페이드 깊이와 넓이는 직선역 구간인 신흥역에서 가장 심하였으며, 레벨 교차율은 짧은 페이드가 빈번하게 발생하는 판암역에서 가장 심하게 나타났다. 따라서 신호 성능에 영향을 주는 페이딩 현상은 곡선역에 비해 직선역에서 더욱 심하게 발생하는 것을 알 수 있다. This paper deals with the measurements of wireless image signal in subway tunnels at 2.45GHz. Measurements have been conducted in 3 subway stations with different types; a straight tunnel and two curved tunnels. As a analysis result for the measured data, we found that the signal level inside straight tunnel by the strong multipath waves fluctuate deeply compared to the curved tunnel. The path loss exponent for the Shin-hung station with the straight tunnel is 2.5, those for the Pan-am and Dae-dong station with curved tunnels are 1.6 and 1.9, respectively. The fade depth and width at 50% point became relatively serious at Shin-hung station, the level crossing rate inside the Pan-am station is larger than the other stations. Therefore, it can be concluded that the fading phenomena affect to the signal performance generate seriously at straight tunnel compared to the curved tunnel.
경기도 지역의 유우 유방염에 관한 조사 3. 한수이남지방의 젖소 유방염 발생실태
송기홍,조중현,홍순종,Song, Gi Hong,Cho, Joong Hyon,Hong, Jong Soon 대한수의학회 1975 大韓獸醫學會誌 Vol.15 No.1
A total of 2,065 quarter milk samples of 534 dair cows from 35 herds were examined for mastis and the results obtained were as follows: 1. 654 quarters (31.6%) of 301 dairy cows (56.3%) from 34 herds (97.1%) were infected with mastitis. It was found that 8 cows (1.5%) showed clinical mastitis and other cows were subclinical. 2. Low infection rate of mastis was shown in first delivery cattle and higher infection rate in more deliverable of cattle. 3. The main causative organisms of the matitis were Staphylococcus aureus (19.4%), Streptococcus agalactiae (11.3%) and Streptococcus dysgalatiae (5%). 4. The majority of causative organisms were very resistant to colistin and highly sensitive to tetracycline. Especially Streptococcus strains were highly sensitive to leukomycin, and Staphylococcus aureus were highly sensitive to tetracycline and the other bacteria were highly sensitive to tetracycline and kanamycin.
RICH INTERNET MATHEMATICAL SOLUTION SYSTEM
송기홍,송태성 한국수학교육학회 2007 純粹 및 應用數學 Vol.14 No.2
Arguably the most important internet technology of today is RIA (rich internet application), whose prime advantage is in improving the user experience ont the web. However, the scope and variety of the RIA technology demand an eclectic guideline to build the mathematical services such as mathematical text, graphs, and animations. This paper sorts out and simplifies the complicated roadmap of the RIA technologies by presenting three design patterns for exposing the functionality of the CAS (computer algebra system) with the web browser as the user interface platform.