考虑到在复杂战场下,传感器部署对敌我双方的态势感知有较大影响,针对使用多信号接收强度传感器对三维目标感知时的传感器最优部署问题,采用费舍尔信息矩阵(Fisher Information Matrix,FIM)的行列式作为最优性能指标,给出了多传感器执...考虑到在复杂战场下,传感器部署对敌我双方的态势感知有较大影响,针对使用多信号接收强度传感器对三维目标感知时的传感器最优部署问题,采用费舍尔信息矩阵(Fisher Information Matrix,FIM)的行列式作为最优性能指标,给出了多传感器执行单目标感知任务时的最优部署几何构型.进一步导出了多传感器在三维情形下的FIM行列式的显式表达.基于该显式表达,得到多目标感知的传感器最优分配以及传感器最优部署几何构型.该方法实现了对敌方目标的精确感知,弥补了因感知误差导致的对战场形势的误判.数值仿真验证了结果的有效性.展开更多
In cloud computing,the number of replicas and deployment strategy have extensive impacts on user's requirement and storage efficiency.Therefore,in this paper,a new definition of file access popularity according to...In cloud computing,the number of replicas and deployment strategy have extensive impacts on user's requirement and storage efficiency.Therefore,in this paper,a new definition of file access popularity according to users' preferences,and its prediction algorithm are provided to predict file access trend with historical data.Files are sorted by priority depending on their popularity.A mathematical model between file access popularity and the number of replicas is built so that the reliability is increased efficiently.Most importantly,we present an optimal strategy of dynamic replicas deployment based on the file access popularity strategy with the overall concern of nodes' performance and load condition.By this strategy,files with high priority will be deployed on nodes with better performance therefore higher quality of service is guaranteed.The strategy is realized in the Hadoop platform.Performance is compared with that of default strategy in Hadoop and CDRM strategy.The result shows that the proposed strategy can not only maintain the system load balance,but also supply better service performance,which is consistent with the theoretical analysis.展开更多
文摘考虑到在复杂战场下,传感器部署对敌我双方的态势感知有较大影响,针对使用多信号接收强度传感器对三维目标感知时的传感器最优部署问题,采用费舍尔信息矩阵(Fisher Information Matrix,FIM)的行列式作为最优性能指标,给出了多传感器执行单目标感知任务时的最优部署几何构型.进一步导出了多传感器在三维情形下的FIM行列式的显式表达.基于该显式表达,得到多目标感知的传感器最优分配以及传感器最优部署几何构型.该方法实现了对敌方目标的精确感知,弥补了因感知误差导致的对战场形势的误判.数值仿真验证了结果的有效性.
基金Supported by the National Natural Science Foundation of China(No.61170209,61272508,61202432,61370132,61370092)
文摘In cloud computing,the number of replicas and deployment strategy have extensive impacts on user's requirement and storage efficiency.Therefore,in this paper,a new definition of file access popularity according to users' preferences,and its prediction algorithm are provided to predict file access trend with historical data.Files are sorted by priority depending on their popularity.A mathematical model between file access popularity and the number of replicas is built so that the reliability is increased efficiently.Most importantly,we present an optimal strategy of dynamic replicas deployment based on the file access popularity strategy with the overall concern of nodes' performance and load condition.By this strategy,files with high priority will be deployed on nodes with better performance therefore higher quality of service is guaranteed.The strategy is realized in the Hadoop platform.Performance is compared with that of default strategy in Hadoop and CDRM strategy.The result shows that the proposed strategy can not only maintain the system load balance,but also supply better service performance,which is consistent with the theoretical analysis.
