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无线个域网应用环境下速率自适应算法的研究 被引量:1
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作者 叶芝慧 沈连丰 +1 位作者 沈克勤 陈锦泰 《通信学报》 EI CSCD 北大核心 2004年第4期160-167,共8页
首先对无线个域网(WPAN)应用环境下的干扰模型进行了分析,在此基础上提出了在WPAN工作的系统中引入速率自适应控制算法以提高诸系统的抗干扰性能,并减小对系统内其它设备及不同系统间设备的相互干扰.文章对自适应速率控制算法进行了分析... 首先对无线个域网(WPAN)应用环境下的干扰模型进行了分析,在此基础上提出了在WPAN工作的系统中引入速率自适应控制算法以提高诸系统的抗干扰性能,并减小对系统内其它设备及不同系统间设备的相互干扰.文章对自适应速率控制算法进行了分析,然后以蓝牙系统为例,给出了自适应速率控制算法对蓝牙系统性能改善的程度,重点讨论了对系统误比特率的影响.仿真结果显示,在理想反馈信道条件下,随着单信道信噪比的改善,自适应速率控制系统的最佳误比特率比固定速率传输系统有1~3个数量级的改善;即使采用简单的双速率自适应控制系统,也可以得到1~2个数量级的改善.由此得到的结果同样可应用于其它工作于无线个域网的系统. 展开更多
关键词 无线个域网 自适应速率控制 固定速率系统 蓝牙系统 IEEE 802.11b
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Seed and Wasp Production in the Mutualism of Figs and Fig Wasps 被引量:1
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作者 YaoJin-yan ZhaoNan-xian +3 位作者 ChenYi-zhu JiaXiao-cheng DengYuan YuHui 《Forestry Studies in China》 CAS 2005年第1期25-28,共4页
Figs (Moracea: Ficus) and fig wasps (Hymenoptera: Chlocloids: Agaonideae) depend on each other to complete their reproduction. Monoecious fig species and their pollinating wasps are in conflict over the use of fig ov... Figs (Moracea: Ficus) and fig wasps (Hymenoptera: Chlocloids: Agaonideae) depend on each other to complete their reproduction. Monoecious fig species and their pollinating wasps are in conflict over the use of fig ovaries which can either produce one seed or one wasp. From observation on Ficus virens Ait., we showed that female flowers with outer layer of ovaries (near to the wall of syconium) had no significant difference from that with inner and interval layer of ovaries (near to the syconium cavity), in which most seeds and wasps were produced. This meant that fig tree provided the same potential resource for seed and wasps production. Observation indicated that there was usually only one foundress in syconium at female flower phase and no com- petition pollinators. Measurement of the style length of female flowers and the ovipositor of pollinators indicated that most ovaries could be reached by pollinator’s ovipositor. However, at the male flower phase, production of seeds was significantly more than that of wasps including non-pollinating wasps but there was no significant difference between seed and pollinating wasp production when without non-pollinating wasps produced. This result indicated that non-pollinating wasps competed ovaries not with seeds but with pollinating wasps for ovipositing. Bagged experiment showed that the sampling fig species was not self-sterile which was important for figs and wasps to survive bad season. Seed production in self-pollinated figs was not significantly different from total wasps in- cluding non-pollinating ones. This might be related with the weaker competition among wasps since bagged figs were not easy to reach by wasps from outside. 展开更多
关键词 FICUS Ficus wasp mutualism conflicts seed and wasp production Seed and Wasp Production in the Mutualism of Figs and Fig Wasps Yao Jin-yan1 2 Zhao Nan-xian1 Chen Yi-zhu1* Jia Xiao-cheng1 2 Deng Yuan1 2 Yu hui1 2 1South China Botanical Garden Chinese Academy of Sciences Guangzhou 510650 P. R. China 2Graduate School of the Chinese Academy of Sciences Beijing 100039 P. R. China ABSTRACT Figs (Moracea: Ficus) and fig wasps (Hymenoptera: Chlocloids: Agaonideae) depend on each other to complete their reproduction. Monoecious fig species and their pollinating wasps are in conflict over the use of fig ovaries which can either produce one seed or one wasp. From observation on Ficus virens Ait. we showed that female flowers with outer layer of ovaries (near to the wall of syconium) had no significant difference from that with inner and interval layer of ovaries (near to the syconium cavity) in which most seeds and wasps were produced. This meant that fig tree provided the same potential resource for seed and wasps production. Observation indicated that there was usually only one foundress in syconium at female flower phase and no com- petition pollinators. Measurement of the style length of female flowers and the ovipositor of pollinators indicated that most ovaries could be reached by pollinator’s ovipositor. However at the male flower phase production of seeds was significantly more than that of wasps including non-pollinating wasps but there was no significant difference between seed and pollinating wasp production when without non-pollinating wasps produced. This result indicated that non-pollinating wasps competed ovaries not with seeds but with pollinating wasps for ovipositing. Bagged experiment showed that the sampling fig species was not self-sterile which was important for figs and wasps to survive bad season. Seed production in self-pollinated figs was not significantly different from total wasps in- cluding non-pollinating
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