• Title/Summary/Keyword: CMA

Search Result 282, Processing Time 0.025 seconds

[ $^{13}CO$ ] OBSERVATIONS OF CMa OB1/RA REGION

  • KIM BONG GYU;KAWAMURA AKINO;FUKUI YASUO
    • Journal of The Korean Astronomical Society
    • /
    • v.29 no.spc1
    • /
    • pp.193-194
    • /
    • 1996
  • A large scale $^{13}CO$(J=1-0) survey was made for CMa OB1/R1 region in $220^{\circ}{\le}{\iota}{\le}230^{\circ}$ and $-10^{\circ}{\le}b{\le}10^{\circ}$ with a 8' spacing by using the 4 m radio telescope of Nagoya University. 34 isolated clouds were identified in this survey. Among them, two clouds were firstly identified by us. The observed LSR velocity indicate that almost of the all clouds are located in the Local arm, except two extreme velocity. The mass spectrum of the clouds in the Local arm is best fitted by a power-law index of 1.6.

  • PDF

A Study on Performance Comparison of Bussgang-type Adaptive Blind Algorithms (Bussgang계열의 적응 Blind 알고리듬들의 성능비교에 관한 연구)

  • Kim, Hyoung-Seok;Kang, Hyun-Cheol;Byun, Youn-Shik
    • The Journal of the Acoustical Society of Korea
    • /
    • v.14 no.5
    • /
    • pp.20-28
    • /
    • 1995
  • This paper studied adaptive blind equalizer which belong to Bussgang type. It is well known that blind equalizer performs equalization without using a training sequence. Especially, this paper concentrated on real time processing of them. The channel characteristic was obtained from measurements taken in a real urban multipath environment. A T/2 fractionally-spaced equalizer was used at the receiving end. Our computer simulations demonstrated that Stop and Go, Benveniste-Goursat, and optimal Bussgang algorithms have relatively low MSE property. CMA shows faster convergence property than any other of Bussgang type algorithm.

  • PDF

Convergence Rate Improvement of the Blind Equalization Algorithm for QAM System using Selective NCMA (QAM 시스템에 선택적으로 NCMA를 적용한 블라인드 등화 알고리즘의 수렴속도 개선)

  • 강윤석;안상식
    • Proceedings of the IEEK Conference
    • /
    • 1999.11a
    • /
    • pp.43-46
    • /
    • 1999
  • Blind equalizers recover the transmitted data using signal's statistical characteristics only. Because of its computational simplicity and fast convergence rate, CMA is widely used in practice. Blind equalizers, however, converge much slowly than conventional equalizers which use the training signals. In order to improve the convergence rate, many modified blind equalization algorithms have been proposed. Among those, Normalized CMA (NCMA) was applied to increase the convergence rate by using the large step size. Unfortunately it can only be applied for the constant modulus signal constellation scheme. this paper, we propose the Selective NCMA (SNCMA) that improve the convergence rate of blind equalization algorithms by using NCMA for non-constant modulus signalling method such as QAM constellation. We achieved fast start-up convergence rate and reduced steady-state residual error.

  • PDF

A Study on Channel Equalization for Asynchronous DS-CDMA Systems (비동기 DS-CDMA 시스템에서 채널 등화에 관한 연구)

  • 민장기
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.25 no.10B
    • /
    • pp.1760-1768
    • /
    • 2000
  • Blind Equalization Method without training sequences is proposed for channel efficiency in mobile communication system for asynchronous multi-user DS-CDMA. the risk of mis-convergence of weak-power users is increased because of small regions of convergence in case of near-far effect in CMA(Constant Modulus Algorithm) which is the simplest has high performance and widely implemented. In despite the problem a equalization using Newton method has higher performance than a conventional method in squared error and eye-pattern.

  • PDF

Quadrant-partitioned Blind Equalization Algorithm for QAM Demodulation (QAM 복조용 4분면 분할 자력복구 채널등화 알고리즘)

  • Ryu, Seok-Kyu;Hwang, Hu-Mor
    • Proceedings of the KIEE Conference
    • /
    • 1998.11b
    • /
    • pp.627-629
    • /
    • 1998
  • We propose a robust blind equalization algorithm based on quadrant-partitioned constellations for QAM demodulation. The algorithm divides the received M-QAM constellations into simple four quadrant. The channel equalization for symbols in each quadrant can be accomplished fast and reliably using the Constant Modulus Algorithm(CMA) and the Stop-and-Go Algorithm(SGA). Test results confirm that the proposed algorithm with lower complexity outperforms both the CMA and the SGA in reducing the SER as well as the MSE at the equalizer output.

  • PDF

Provably Secure Aggregate Signcryption Scheme

  • Ren, Xun-Yi;Qi, Zheng-Hua;Geng, Yang
    • ETRI Journal
    • /
    • v.34 no.3
    • /
    • pp.421-428
    • /
    • 2012
  • An aggregate signature scheme is a digital signature scheme that allows aggregation of n distinct signatures by n distinct users on n distinct messages. In this paper, we present an aggregate signcryption scheme (ASC) that is useful for reducing the size of certification chains (by aggregating all signatures in the chain) and for reducing message size in secure routing protocols. The new ASC scheme combines identity-based encryption and the aggregation of signatures in a practical way that can simultaneously satisfy the security requirements for confidentiality and authentication. We formally prove the security of the new scheme in a random oracle model with respect to security properties IND-CCA2, AUTH-CMA2, and EUF-CMA.

Adaptive $CO_2$Fixation Nitrate assimilation of Portulace oleracea in Zoysia japonica Community (잔디군락에 출현하는 쇠비름의 $CO_2$고정과 질소동화)

  • 장남기;김희백
    • Asian Journal of Turfgrass Science
    • /
    • v.8 no.1
    • /
    • pp.13-18
    • /
    • 1994
  • $CO_2$와 질소동화작용에 있어서의 잎과 줄기간의 세포간 관계가 잔디군락의 자연 환경 상태하에서 자라는 Portulaca oleracea 에서 조사되었다. 기공이 줄기에서는 관찰되지 않는 반면 잎에서는 $1cm^2$당 3,275개가 나타났다. 어린 쇠비름 잎의 기공의 조헝운 범에누누 높고 낮에는 낮다. 최고 활성을 갖는 마디의 순서는 위에서 아래로 떨어짐에 따라 변화한다.P.oleracea 의 줄기조직은 CMA의 최고 활성을 나타내었으나 잎에서는 CMA의 활성이 나타나지 않았다. 빠른 산의 성화는 새벽에 원줄기에서 보여지나 줄기는 서서히 증가하는 것 밖에 관찰되지 않는다. RuPB carboxy-lase의 활성은 거의 관찰 되지 않는다. 특히 잎새에서의 PEP carboxylase의 활성은 이른 아침에 줄기에서는 낮고 잎에서는 매우 높음을 보여준다. 이런 결과는 새벽에 열려진 기공을 통과할$CO_2$가 PEP carboxylase에 의해 잎에서 동화되고 $C_4$생산물이 줄기로 이동함을 나타낸다. Nitrate 축적과 nitrate reductase, nitrite reductase, glutamine symithetase, gluamate symthase, glutamade dehydrogenase의 농도는 잎보다 줄기에서 더 높았고 밤보다 낮에 더 높다. 이것은 뿌리를 통해 흡수된 nitrate의 상당한 양이 줄기에서 동화되고 줄기 조직을 통해 잎으로 이동되어 거기에서 감소된다.

  • PDF

A Stop-and-Go Dual-Mode Modified Constant Modulus Algorithm for Adaptive Blind Equalization of High-Order QAM Signals (고밀도 광 기록 채널을 위한 터보 코드와 터보 등화기를 연접한 데이터 복호 방법)

  • 임창현;김기윤;김동규;최형진
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.25 no.6B
    • /
    • pp.1074-1081
    • /
    • 2000
  • In this paper, in order to speed up the convergence process and improve the steady mean square error simultaneously, we propose the Stop-and-Go Dual Mode Modified Constant Modulus Algorithm(SAG DM MCMA) for adaptive blind channel equalization of high order QAM. The proposed algorithm is a hybrid scheme of the Modified CMA that treat error signals with real and imaginary components of the equalizer output, the concept of dual mode CMA, and Stop-and-Go algorithm. As a result it can prevent blind equalization from converging to incorrect direction and simultaneously operates reliably for tap weight adaptation. We demonstrate via simulation that the proposed algorithm achieves lower steady state mean square error and residual ISI than the conventional algorithms under high order QAM signals and severe channel environment.

  • PDF

Pathogenicity of Pythium Species Associated with Seed and Seedling Rot in Water-Seeded Rice (벼 담수직파재배에서 벼모썩음병에 관련된 Pythium속 균의 병원성)

  • ;R. W. Schneider
    • Korean Journal Plant Pathology
    • /
    • v.12 no.4
    • /
    • pp.402-406
    • /
    • 1996
  • Pythium 5종, 16균주를 공시하여 담수직파한 벼에 대한 병원성을 CMA 배지와 growth chamber 검정법에 의하여 검정한 결과 P. arrhenomanes 1398 균주가 가장 강한 병원성을 보였으며, 다음은 균주에 따라 차이가 있었으나 P. irregulare와 P. spinosum도 병원성이 강하였으며, P. dissotocum과 P. catenulatum의 균주는 병원성이 약하거나 없엇다. CMA 배지 검정때 P. arrhenomanes 1398 균주의 병원성은 주.dirks 2$0^{\circ}C$ 또는 3$0^{\circ}C$의 항온처리보다 주간 3$0^{\circ}C$, dirks 2$0^{\circ}C$의 변온 처리에서 높았다. Growth chamber 검정법으로 병원성을 검정할 때에는 벼알접종원을 이용하는 것이 효과적이었다.

  • PDF

The role of The Ministry of Commerce and The Capital Market Authority (CMA) in Protecting Shareholders and Holding Directors accountable in Saudi's Corporations

  • Alzhrani, Abdulrahman AA
    • International Journal of Computer Science & Network Security
    • /
    • v.22 no.8
    • /
    • pp.187-196
    • /
    • 2022
  • The law gives the Ministry of Commerce the power of monitoring, oversight, and accountability for corporations in general. However, Article 219 of the Companies Law has made oversight of listed companies within the jurisdiction of the Capital Market Authority, but this exception, in the author's opinion, is not clear because the law obligated the Ministry of Commerce to monitor and account for joint-stock companies, whether they were listed or not included in some cases.