基于WLAN(Wireless Local Area Networks)的无线定位是移动互联网领域的重要研究内容之一.其中,指纹定位方法已成为主流,此类方法的特点之一在于需要离线训练数据与在线测试数据具有严格的一致性.但在实际环境中,无线信号数据波动较大,...基于WLAN(Wireless Local Area Networks)的无线定位是移动互联网领域的重要研究内容之一.其中,指纹定位方法已成为主流,此类方法的特点之一在于需要离线训练数据与在线测试数据具有严格的一致性.但在实际环境中,无线信号数据波动较大,存在显著的时效性问题.这导致一定时间后,定位模型的预测精度不断下降.文中提出一种具有时效机制的增量式定位方法(Timeliness Managing Extreme Learning Machine,TMELM),一方面满足实际系统的应用需求,可随时加入新的训练数据进行在线增量式学习,另一方面融入时效机制,以最大化新增训练数据对定位模型的贡献,保持定位模型的精度.实验表明,在实际WLAN定位数据集上,文中方法相比于传统的几种增量式学习方法,具有明显的时效优势,能获得更好的定位精度.展开更多
Aimed at the difficulty in revealing the vibration localization mechanism of mistuned bladed disks by using simple non-linear model,a mechanical model of the bladed disk with random mistuning of hysteretic dry frictio...Aimed at the difficulty in revealing the vibration localization mechanism of mistuned bladed disks by using simple non-linear model,a mechanical model of the bladed disk with random mistuning of hysteretic dry friction damping was established.Then,the incremental harmonic balance method was used to analyze the effects of the parameters of bladed disks,such as the mistuning strength of dry friction force,coupled strength,viscous damping ratio and friction strength,on the forced response of the bladed disks.The results show that the vibrational energy localization phenomenon turns up in the tuned bladed disks if the nonlinear friction damping exists,and the random mistuning of the dry friction force intensifies this kind of vibration localization.展开更多
文摘基于WLAN(Wireless Local Area Networks)的无线定位是移动互联网领域的重要研究内容之一.其中,指纹定位方法已成为主流,此类方法的特点之一在于需要离线训练数据与在线测试数据具有严格的一致性.但在实际环境中,无线信号数据波动较大,存在显著的时效性问题.这导致一定时间后,定位模型的预测精度不断下降.文中提出一种具有时效机制的增量式定位方法(Timeliness Managing Extreme Learning Machine,TMELM),一方面满足实际系统的应用需求,可随时加入新的训练数据进行在线增量式学习,另一方面融入时效机制,以最大化新增训练数据对定位模型的贡献,保持定位模型的精度.实验表明,在实际WLAN定位数据集上,文中方法相比于传统的几种增量式学习方法,具有明显的时效优势,能获得更好的定位精度.
基金Project(2007CB707706) supported by the National Basic Research Program of China
文摘Aimed at the difficulty in revealing the vibration localization mechanism of mistuned bladed disks by using simple non-linear model,a mechanical model of the bladed disk with random mistuning of hysteretic dry friction damping was established.Then,the incremental harmonic balance method was used to analyze the effects of the parameters of bladed disks,such as the mistuning strength of dry friction force,coupled strength,viscous damping ratio and friction strength,on the forced response of the bladed disks.The results show that the vibrational energy localization phenomenon turns up in the tuned bladed disks if the nonlinear friction damping exists,and the random mistuning of the dry friction force intensifies this kind of vibration localization.
