在基于Mesh-under的IPv6低功耗无线个域网(IPv6over low-power wireless personal area networks,6LoWPAN)中,针对传输路径上中间节点重传缓存溢出导致重传数据分片丢失,造成网络性能下降等问题,提出一种基于Mesh-under的备用缓存机制...在基于Mesh-under的IPv6低功耗无线个域网(IPv6over low-power wireless personal area networks,6LoWPAN)中,针对传输路径上中间节点重传缓存溢出导致重传数据分片丢失,造成网络性能下降等问题,提出一种基于Mesh-under的备用缓存机制。本文所提机制根据传输路径上各节点重传缓存使用情况及数据分片剩余跳数等信息,设置动态重传缓存门限,并为超过该门限的节点从其邻居节点中挑选合适的备用缓存节点,从而完成数据分片的缓存与重传过程,达到均衡使用各节点重传缓存的目的。结果表明,所提机制能够有效避免重传缓存溢出,减小网络能耗,同时进一步提高目的端重组成功率。展开更多
基于仿真互操作标准组织(S im u lation In teroperab ility S tandards O rgan ization,S ISO)C4ISR/M&S互操作技术参考模型和高层体系结构(H igh L eve lA rch itecture,HLA),C4ISR/M&S互操作HLA仿真设施为架构仿真系统运行...基于仿真互操作标准组织(S im u lation In teroperab ility S tandards O rgan ization,S ISO)C4ISR/M&S互操作技术参考模型和高层体系结构(H igh L eve lA rch itecture,HLA),C4ISR/M&S互操作HLA仿真设施为架构仿真系统运行体系提出了面向方面框架(A spect O rien ted F ram ew ork,AOF)和应用服务平台的技术。AOF能控制C4ISR/M&S互操作所引起的仿真系统结构复杂化,应用服务平台则能丰富仿真系统的运行环境,仿真设施可作为仿真系统通用运行体系的基础组件,支持复杂互操作系统开发。展开更多
A numerical investigation is carried out to study the effect of splitter＇s inclination angle behind an inclined square cylinder on the forced convection heat transfer in a plan channel using the lattice Boltzmann met...A numerical investigation is carried out to study the effect of splitter＇s inclination angle behind an inclined square cylinder on the forced convection heat transfer in a plan channel using the lattice Boltzmann method （LBM）. The simulations are conducted for the pertinent parameters in the following ranges： the Reynolds number Re=50-300, the gap ratio G/d = 2, and the splitter＇s inclination angle 8 = 0°-90°. The results show that with the increase in the angle of the splitter, the drag coefficient initially decreases and then increases. Moreover, the time-averaged Nusselt number at a certain angle increases noticeably.展开更多
The physical aging behavior of atactic polystyrene (aPS) films achieved under different drawing conditions has been studied by optical birefringence and modulate differential scanning: calorimeter (m.d.s.c.). The resu...The physical aging behavior of atactic polystyrene (aPS) films achieved under different drawing conditions has been studied by optical birefringence and modulate differential scanning: calorimeter (m.d.s.c.). The results show that on annealing at specific temperature below glass transition temperatue (T-g), the enthalpy relaxation (Delta H) and T-g decrease with increasing of birefringence (Delta n). On the other baud, the effect of molecular draw ratio (MDR) is confusing: Delta H and T-g decrease with increasing of MDR in the early stage of aging, but the MDR's effect become unobvious with the development of aging. It may be concluded that the ordered domain generated by the drawing below or above glass transition temperature will affect the development of physical aging behavior. The viewpoint of cohesional entanglement is used to account for the above observations.展开更多
数据关联是智能车同时定位与建图(simultaneous localization and mapping,SLAM)中的一个难点问题.为了快速准确获得数据关联结果,结合连续兼容最近邻(sequential compatibility nearest neighbor,SCNN)算法简单易实现和联合兼容分支定...数据关联是智能车同时定位与建图(simultaneous localization and mapping,SLAM)中的一个难点问题.为了快速准确获得数据关联结果,结合连续兼容最近邻(sequential compatibility nearest neighbor,SCNN)算法简单易实现和联合兼容分支定界(joint compatibility brarch and bound,JCBB)算法最优理念强的优点,提出了一种快速联合数据关联(fast joint data association,FJDA)算法.该算法首先在局部地图中采用SCNN数据关联算法处理所有的观测-特征对,得到关联结果;其次判断关联结果的准确性,若关联出错,则采用具有噪声的基于密度的聚类方法(densitybased spatial clustering of applications with noise,DBSCAN)对当前时刻的观测量进行分组,然后在每一小组中采用JCBB算法进行数据关联,最终将每一小组的关联解融合得到最终的关联结果.通过仿真实验对提出的算法、SCNN算法以及JCBB算法的性能进行了比较,结果表明提出的关联算法实时性强,准确度高.展开更多
文摘在基于Mesh-under的IPv6低功耗无线个域网(IPv6over low-power wireless personal area networks,6LoWPAN)中,针对传输路径上中间节点重传缓存溢出导致重传数据分片丢失,造成网络性能下降等问题,提出一种基于Mesh-under的备用缓存机制。本文所提机制根据传输路径上各节点重传缓存使用情况及数据分片剩余跳数等信息,设置动态重传缓存门限,并为超过该门限的节点从其邻居节点中挑选合适的备用缓存节点,从而完成数据分片的缓存与重传过程,达到均衡使用各节点重传缓存的目的。结果表明,所提机制能够有效避免重传缓存溢出,减小网络能耗,同时进一步提高目的端重组成功率。
文摘基于仿真互操作标准组织(S im u lation In teroperab ility S tandards O rgan ization,S ISO)C4ISR/M&S互操作技术参考模型和高层体系结构(H igh L eve lA rch itecture,HLA),C4ISR/M&S互操作HLA仿真设施为架构仿真系统运行体系提出了面向方面框架(A spect O rien ted F ram ew ork,AOF)和应用服务平台的技术。AOF能控制C4ISR/M&S互操作所引起的仿真系统结构复杂化,应用服务平台则能丰富仿真系统的运行环境,仿真设施可作为仿真系统通用运行体系的基础组件,支持复杂互操作系统开发。
文摘A numerical investigation is carried out to study the effect of splitter＇s inclination angle behind an inclined square cylinder on the forced convection heat transfer in a plan channel using the lattice Boltzmann method （LBM）. The simulations are conducted for the pertinent parameters in the following ranges： the Reynolds number Re=50-300, the gap ratio G/d = 2, and the splitter＇s inclination angle 8 = 0°-90°. The results show that with the increase in the angle of the splitter, the drag coefficient initially decreases and then increases. Moreover, the time-averaged Nusselt number at a certain angle increases noticeably.
基金This work was Supported by the National Basic Research Project-Macromolecular Condensed State
文摘The physical aging behavior of atactic polystyrene (aPS) films achieved under different drawing conditions has been studied by optical birefringence and modulate differential scanning: calorimeter (m.d.s.c.). The results show that on annealing at specific temperature below glass transition temperatue (T-g), the enthalpy relaxation (Delta H) and T-g decrease with increasing of birefringence (Delta n). On the other baud, the effect of molecular draw ratio (MDR) is confusing: Delta H and T-g decrease with increasing of MDR in the early stage of aging, but the MDR's effect become unobvious with the development of aging. It may be concluded that the ordered domain generated by the drawing below or above glass transition temperature will affect the development of physical aging behavior. The viewpoint of cohesional entanglement is used to account for the above observations.
文摘数据关联是智能车同时定位与建图(simultaneous localization and mapping,SLAM)中的一个难点问题.为了快速准确获得数据关联结果,结合连续兼容最近邻(sequential compatibility nearest neighbor,SCNN)算法简单易实现和联合兼容分支定界(joint compatibility brarch and bound,JCBB)算法最优理念强的优点,提出了一种快速联合数据关联(fast joint data association,FJDA)算法.该算法首先在局部地图中采用SCNN数据关联算法处理所有的观测-特征对,得到关联结果;其次判断关联结果的准确性,若关联出错,则采用具有噪声的基于密度的聚类方法(densitybased spatial clustering of applications with noise,DBSCAN)对当前时刻的观测量进行分组,然后在每一小组中采用JCBB算法进行数据关联,最终将每一小组的关联解融合得到最终的关联结果.通过仿真实验对提出的算法、SCNN算法以及JCBB算法的性能进行了比较,结果表明提出的关联算法实时性强,准确度高.
