利用移动数据收集器(mobile data collector,简称MDC)进行传感器网络中感知数据的收集,可以有效地减少传感器将数据发送到静止基站的传输跳数,节约网络的能量,延长网络寿命.此外,MDC通过循环收集传感器数据或承担数据转发的功能,避免节...利用移动数据收集器(mobile data collector,简称MDC)进行传感器网络中感知数据的收集,可以有效地减少传感器将数据发送到静止基站的传输跳数,节约网络的能量,延长网络寿命.此外,MDC通过循环收集传感器数据或承担数据转发的功能,避免节点间由于多跳传输引起的能量空洞(energy hole)以及节点失效造成的传输链路中断等问题.MDC的移动性也为无线传感器网络的研究带来新的挑战.研究基于移动协助数据收集的无线传感器网络结构,分类总结了近年来提出的一些典型的基于MDC的算法和协议,着重讨论了MDC在网络能量、延迟、路由和传输等方面带来的性能变化.最后,进行了各种算法的比较性总结,针对传感器网络中MDC的研究提出了亟待解决的问题,并展望了其未来的发展方向.展开更多
Electrical capacitance volume tomography(ECVT) is a recently-developed technique for real-time,non-invasive 3D monitoring of processes involving materials with strong contrasts in dielectric permittivity.This work is ...Electrical capacitance volume tomography(ECVT) is a recently-developed technique for real-time,non-invasive 3D monitoring of processes involving materials with strong contrasts in dielectric permittivity.This work is first application of the method to visualization of water flow in soil.We describe the principles behind the method,and then demonstrate its use with a simple laboratory infiltration experiment.32 ECVT sensors were installed on the sides of an empty PVC column.Water was poured into the column at a constant rate,and ECVT data were collected every second.The column was then packed with dry sand and again supplied with water at a constant rate with data collected every second.Data were analyzed to give bulk average water contents,which proved consistent with the water supply rates.Data were also analyzed to give 3D images(216 voxels) allowing visualization of the water distribution during the experiments.Result of this work shows that water infiltration into the soil,wall flow,progress of the unstable wetting front and the final water distribution are clearly visible.展开更多
文摘利用移动数据收集器(mobile data collector,简称MDC)进行传感器网络中感知数据的收集,可以有效地减少传感器将数据发送到静止基站的传输跳数,节约网络的能量,延长网络寿命.此外,MDC通过循环收集传感器数据或承担数据转发的功能,避免节点间由于多跳传输引起的能量空洞(energy hole)以及节点失效造成的传输链路中断等问题.MDC的移动性也为无线传感器网络的研究带来新的挑战.研究基于移动协助数据收集的无线传感器网络结构,分类总结了近年来提出的一些典型的基于MDC的算法和协议,着重讨论了MDC在网络能量、延迟、路由和传输等方面带来的性能变化.最后,进行了各种算法的比较性总结,针对传感器网络中MDC的研究提出了亟待解决的问题,并展望了其未来的发展方向.
文摘Electrical capacitance volume tomography(ECVT) is a recently-developed technique for real-time,non-invasive 3D monitoring of processes involving materials with strong contrasts in dielectric permittivity.This work is first application of the method to visualization of water flow in soil.We describe the principles behind the method,and then demonstrate its use with a simple laboratory infiltration experiment.32 ECVT sensors were installed on the sides of an empty PVC column.Water was poured into the column at a constant rate,and ECVT data were collected every second.The column was then packed with dry sand and again supplied with water at a constant rate with data collected every second.Data were analyzed to give bulk average water contents,which proved consistent with the water supply rates.Data were also analyzed to give 3D images(216 voxels) allowing visualization of the water distribution during the experiments.Result of this work shows that water infiltration into the soil,wall flow,progress of the unstable wetting front and the final water distribution are clearly visible.
