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TLTS:大规模无线传感器网络下基于簇的两级TDMA调度协议 被引量:16
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作者 龚海刚 刘明 王晓敏 《计算机研究与发展》 EI CSCD 北大核心 2007年第1期71-77,共7页
媒质接入控制子层是节点能量消耗的主要所在,因此无线传感器网络设计的关键问题之一是媒质的接入控制.基于TDMA的MAC协议具有固有的节能特性,但是其可扩展性较差.基于簇的TDMA协议则可有效提高系统的可扩展性,但同时带来了簇间传输干扰... 媒质接入控制子层是节点能量消耗的主要所在,因此无线传感器网络设计的关键问题之一是媒质的接入控制.基于TDMA的MAC协议具有固有的节能特性,但是其可扩展性较差.基于簇的TDMA协议则可有效提高系统的可扩展性,但同时带来了簇间传输干扰问题.针对此问题提出了一种基于簇的两级TDMA调度协议——TLTS协议.通过两级TDMA调度,避免了簇间传输干扰,提高了能量有效利用率.实验结果显示,当节点密度较高时,TLTS协议更适合用于大规模部署的无线传感器网络中. 展开更多
关键词 无线传感器网络 媒质接入控制 时分复用 能量有效率 簇覆盖
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A novel ring vibrating gyroscope based on side piezo-electrodes 被引量:4
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作者 周鑫 吴宇列 +2 位作者 吴学忠 张勇猛 郑煜 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第3期555-561,共7页
Solid-state wave gyroscope is one kind of high-performance vibrating gyroscopes. The present work develops a new type of solid-state wave gyroscope—a ring vibrating gyroscope driven by piezo-electrodes located on the... Solid-state wave gyroscope is one kind of high-performance vibrating gyroscopes. The present work develops a new type of solid-state wave gyroscope—a ring vibrating gyroscope driven by piezo-electrodes located on the sidewall of the structure. It has advantages of large vibrating amplitude, high energy conversion efficiency and compact structure. The working principle of the piezoelectric ring vibrating gyroscope is based on the inertia effect of the standing wave in the axisymmetric resonator caused by Coriolis force. The finite element method(FEM) analysis has been implemented to characterize the ring type resonator. The prototypal gyroscope was manufactured and has been trimmed by mechanical way. The harmonic response of the ring vibrating gyroscope has been tested. The resonating frequency of the ring type resonator is 3715.6 Hz and the frequency split of the two working modes before trimming was about 5 Hz and was reduced to sub-0.01 Hz after trimming procedure. The Q-factor of the ring type resonator was 2504. Then, the turntable experiment was implemented. The measured scale factor k is 9.24 m V/[(°)·s] and the full scale range of the gyroscope is larger than ±300(°)/s. 展开更多
关键词 solid-state wave gyroscope piezoelectric gyroscope side drive ring vibrating gyroscope
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Collision performance of bitubular tubes with diaphragms 被引量:1
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作者 董海鹏 高广军 +1 位作者 谢素超 李健 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第9期3657-3665,共9页
A numerical study of bitubular tubes with diaphragms compared with single and bitubular tubes subjected to dynamic axial impact force was presented. At first, the energy absorption response of the composite structure ... A numerical study of bitubular tubes with diaphragms compared with single and bitubular tubes subjected to dynamic axial impact force was presented. At first, the energy absorption response of the composite structure under axial loading was analyzed by finite element simulation. The results show that the efficiency of energy absorption can be improved by introducing diaphragms to the double-walled columns. Then, the effect of the amount and location of diaphragms, the shape and the size of the inner tubes, and the thickness of the composite structures were also studied numerically. The collision performance of the composite structure is affected by the deformation of diaphragms, as well as the interaction of outer and inner tube. The non-uniform distribution of diaphragms can improve the energy absorption efficiency of structures for a constant number of diaphragms. The specific energy absorption of the hexagonal inner tube is the highest, followed by the circular, octagonal and square ones. 展开更多
关键词 bitubular tube DIAPHRAGM energy absorption CRASHWORTHINESS
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