为了降低水声信道强多径效应、大多普勒频移等特性对水声通信系统的影响,提出一种基于极化码的正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)的水声通信系统。选择极化(Polar)码作为信道编码方案,通过量化信道输出直...为了降低水声信道强多径效应、大多普勒频移等特性对水声通信系统的影响,提出一种基于极化码的正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)的水声通信系统。选择极化(Polar)码作为信道编码方案,通过量化信道输出直接统计信道转移概率,替代通过信道估计得到的信道冲激响应,再计算转移概率,以降低通信系统的复杂度。在特性随时不变、时变、快时变的3种类型水声信道模型下,分别基于蒙特卡罗算法构造Polar码。仿真结果表明,Polar码在3种信道上的编码增益优于同码长同码率的低密度奇偶校验(Low Density Parity Check,LDPC)码和Turbo码,且信道条件越复杂,取得的编码增益越大,所提系统能够明显降低信道多径效应、多普勒频移对水声通信系统的扰乱,提高系统的可靠性。展开更多
In Brassica napus L.(rapeseed),complete genic male sterility(GMS)plays an important role in the utilization of heterosis.Although microRNAs(miRNAs)play essential regulatory roles during bud development,knowledge of ho...In Brassica napus L.(rapeseed),complete genic male sterility(GMS)plays an important role in the utilization of heterosis.Although microRNAs(miRNAs)play essential regulatory roles during bud development,knowledge of how GMS is regulated by miRNAs in rapeseed is rather limited.In this study,we obtained a novel recessive GMS system,CN12AB.The sterile line CN12A has defects in tapetal diferentiation and degradation.llumina sequencing was employed to examine the expression of miRNAs in the buds of CN12A and the fertile line CN12B.We identifed 85 known miRNAs and 120 novel miRNAs that were expressed during rapeseed anther development.When comparing the expression levels of miRNAs between CN12A and CN12B,19 and 18 known miRNAs were found to be difrentially expressed in 0.5--1.0 mm buds and in 2.5--3.0 mm buds,respectively.Among these,the expression levels of 14 miRNAs were higher and the levels of 23 miRNAs were lower in CN12A compared with CN12B.The predicted target genes of these iferentially expressed miRNAS encode protein kinases,F-box domain-containing proteins,MADS-box family proteins,SBP-box gene family members,HD ZIP proteins,floral homeotic protein APETAL A 2(AP2)。and nuclear factor Y,subunit A.These targets have previously been reported to be involved in pollen development and male sterility,suggesting that miRNAs might act as regulators of GMS in rapeseed anthers.Furthermore,RT-qPCR data suggest that one of the dffrentially expressed miRNAs,bna-miR159,plays a role in tapetal differentiation by regulating the expression of transcription factor BnMYB101 and participates in tapetal degradation and infuences callose degradation by manipulating the expression of BnA6.These findings contibute to our understanding of the roles of miRNAs during anther development and the occurrence of GMS in rapeseed.展开更多
文摘为了降低水声信道强多径效应、大多普勒频移等特性对水声通信系统的影响,提出一种基于极化码的正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)的水声通信系统。选择极化(Polar)码作为信道编码方案,通过量化信道输出直接统计信道转移概率,替代通过信道估计得到的信道冲激响应,再计算转移概率,以降低通信系统的复杂度。在特性随时不变、时变、快时变的3种类型水声信道模型下,分别基于蒙特卡罗算法构造Polar码。仿真结果表明,Polar码在3种信道上的编码增益优于同码长同码率的低密度奇偶校验(Low Density Parity Check,LDPC)码和Turbo码,且信道条件越复杂,取得的编码增益越大,所提系统能够明显降低信道多径效应、多普勒频移对水声通信系统的扰乱,提高系统的可靠性。
基金This project was supported by the National Key Research Program of China(2018YFD0100500)the Major Projects for New Varieties of Genetically Modified Organisms,China(2018ZX0801109B)the Agricultural Science and Technology Innovation Project of Gansu Academy of Agricultural Sciences,China(2018GAAS04).
文摘In Brassica napus L.(rapeseed),complete genic male sterility(GMS)plays an important role in the utilization of heterosis.Although microRNAs(miRNAs)play essential regulatory roles during bud development,knowledge of how GMS is regulated by miRNAs in rapeseed is rather limited.In this study,we obtained a novel recessive GMS system,CN12AB.The sterile line CN12A has defects in tapetal diferentiation and degradation.llumina sequencing was employed to examine the expression of miRNAs in the buds of CN12A and the fertile line CN12B.We identifed 85 known miRNAs and 120 novel miRNAs that were expressed during rapeseed anther development.When comparing the expression levels of miRNAs between CN12A and CN12B,19 and 18 known miRNAs were found to be difrentially expressed in 0.5--1.0 mm buds and in 2.5--3.0 mm buds,respectively.Among these,the expression levels of 14 miRNAs were higher and the levels of 23 miRNAs were lower in CN12A compared with CN12B.The predicted target genes of these iferentially expressed miRNAS encode protein kinases,F-box domain-containing proteins,MADS-box family proteins,SBP-box gene family members,HD ZIP proteins,floral homeotic protein APETAL A 2(AP2)。and nuclear factor Y,subunit A.These targets have previously been reported to be involved in pollen development and male sterility,suggesting that miRNAs might act as regulators of GMS in rapeseed anthers.Furthermore,RT-qPCR data suggest that one of the dffrentially expressed miRNAs,bna-miR159,plays a role in tapetal differentiation by regulating the expression of transcription factor BnMYB101 and participates in tapetal degradation and infuences callose degradation by manipulating the expression of BnA6.These findings contibute to our understanding of the roles of miRNAs during anther development and the occurrence of GMS in rapeseed.
