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IMT-2000에서 동적 스위칭 임계점을 이용하는 이중 모드 패킷 전송방식
김장욱,반태원,오창헌,조성준 한국정보통신학회 2003 한국정보통신학회논문지 Vol.7 No.5
A very efficient packet transmission scheme is needed in the radio environment where radio resource is insufficient as compared with the environment of the wired communication. In general, dual mode packet transmission scheme is used broadly. Packets are transmitted through the dedicated or common chamois according to a switching criterion. The general criteria are the length and generation frequency of packet, that is, large and frequent packets are transmitted using a dedicated channel and small and infrequent packets are transmitted using a common channel. The performance of dual mode packet transmission scheme is closely related to the switching criteria. However, it is very difficult to find the optimal switching point because that is not fixed but variable according to the environment such as traffic load, length of generated packets, and the number of channels. In this paper, a new scheme for the dual mode packet transmission scheme using a dynamic switching threshold is proposed where the switching threshold is not fixed but variable according to the network environment. The performance of the proposed method is analyzed using a simulation. From the simulation results, it is shown that the performance of the proposed scheme is not very influenced by the network environment unlike the conventional dual mode packet transmission scheme. 유선 통신환경과 비교해서 무선 자원이 부족한 무선 환경에서는 매우 효율적인 패킷 전송 방식이 필요하다. 일반적으로는 이중 모드 패킷 전송 방식이 널리 사용된다. 스위칭 기준에 따라서, 패킷은 전용채널이 할당되거나 또는 공통의 채널을 통해서 전송된다. 일반적인 기준은 패킷의 길이와 생성 주파수이다. 즉 크고 발생 빈도가 높은 패킷은 전용 채널을 통해서 전송되고 작고 발생빈도가 낮은 패킷은 공통 채널을 통해서 전송된다. 이중 모드 패킷 전송 방식의 성능은 스위칭 기준과 밀접한 관련이 있다. 그렇지만 최적의 스위칭 포인트를 찾는 것은 매우 힘드는데 스위칭 포인트가 고정되어 있는 것이 아니라 트래픽 부하와 생성된 패킷의 길이와 채널의 수와 같은 환경에 따라 변동하기 때문이다. 본 논문에서는 동적 스위칭 임계점(dynamic switching threshold)을 이용하는 이중 모드 패킷 전송 방식을 위한 새로운 기법을 제안한다. 이 방식에서는 스위칭 임계값이 네트워크 환경에 따라서 변동한다. 제안한 방식의 성능은 시뮬레이션을 통해 분석하였다. 시뮬레이션 결과는 기존의 이중 모드 패킷 전송 방식과는 달리 제안한 방식의 성능이 네트워크 환경의 영향을 그다지 받지 않음을 보여준다.
인삼 핵심집단 구축을 위한 2003년 수집자원의 주요 질적형질 특성
김장욱,이정우,조익현,홍지은,방경환 한국약용작물학회 2018 한국약용작물학술대회 발표집 Vol.2018 No.10
Background : Recently, there is an urgent demand for development of new varieties with enhanced resistance to various biotic/abiotic stresses. One generation of ginseng is four years, so it takes a long time to breed. To increase the efficiency of the ginseng breeding and save time and effort, it is necessary to build a ginseng core collection. This study examined the major growth characteristics of genetic sources for the establishment of core collection. Methods and Results : As plant materials, 187 ginseng lines collected in 2003 were used in this study. Ginseng Seeds were harvested at the end of July 2014, sown in mid-November, and cultivated in 2015 for one year in the field and then transplanted into the main field in 2016. All phenotypes including agronomic characteristics, seed yield, and physiological response to biotic/abiotic stresses were investigated according to the ginseng GAP and UPOV guidelines. The stem colors of the collected ginseng germplasm were classified as the five classes; light green, green, light purple, purple and dark purple, but most of them were purple or dark purple. The locations of distribution of anthocyanin coloration in stem were classified into the four classes; proximal end, proximal end and petiole part, the entire stem and the stem with purple not revealed, but most of them were petiole part or the entire stem. The shapes of leaflet were classified the four classes; the long elliptic, elliptic, slender type, and spatulate type. Most of surveyed lines were elliptic type. When the leaflet of ginseng was laterally cut, the shape was classified into the three types; concave type, plane type and convex type. Most of surveyed lines were red berry color. Conclusion : The genetic pool of ginseng is known to be narrow. The results of this study showed similar characteristics among the ginseng fields collected. In the future, we will carry out the survey about quantitative characteristics and correlations of ginseng genetic resources for establishment of Korean ginseng core collection.