研究了多通道分布式主动噪声控制(Distributed Active Noise Control,ANC)系统的空间平滑问题.传统的分布式ANC算法通过本地控制器之间的通信,可以大大提高系统稳定性.但由于每组控制器和误差麦克风分布位置不同,引入的估计偏差影响系...研究了多通道分布式主动噪声控制(Distributed Active Noise Control,ANC)系统的空间平滑问题.传统的分布式ANC算法通过本地控制器之间的通信,可以大大提高系统稳定性.但由于每组控制器和误差麦克风分布位置不同,引入的估计偏差影响系统整体降噪性能.因此,旨在开发一种新型扩散滤波最小均方算法(Diffusion Filtered-x Least Mean Squares,Diff-FxLMS),该算法平衡了空间平滑度和信息交换强度之间的矛盾,从而减少估计偏差.通过对Diff-FxLMS算法性能进行的理论分析,揭示了扩散控制机制,为ANC算法设计提供了理论依据,并在此基础上发展出一种新型的可变平滑度的Diff-FxLMS(Varible Spatial Regularized Diff-FxLMS,VSR-Diff-FxLMS)算法.仿真结果验证了新算法的性能及理论分析的可靠性.展开更多
Epignathus is an extremely rare congenital oropharyngeal teratoma.Here,we report a case of epignathus without intracranial extension in a fetus.The mass was first found by ultrasonography at 22 gestational weeks.Seria...Epignathus is an extremely rare congenital oropharyngeal teratoma.Here,we report a case of epignathus without intracranial extension in a fetus.The mass was first found by ultrasonography at 22 gestational weeks.Serial ultrasound examinations and magnetic resonance imaging confirmed that the fetus had neither central nervous system involvement nor abnormal nose or tooth.The baby was delivered at 37 weeks and six days of gestation via cesarean section set up for ex-utero intrapartum treatment.The postnatal pathologic examination confirmed the presence of mature tissues predominantly containing ectopic central nervous tissue,osseous tissue,and bronchial mucosal tissue.Most cases of epignathus are associated with malformation and death.Ultrasound and magnetic resonance imaging prenatal assessments are very important to facilitate counseling and understand prognosis.In conclusion,the ex-utero intrapartum treatment procedure is a good approach to improve the survival of infants with epignathus.展开更多
文摘研究了多通道分布式主动噪声控制(Distributed Active Noise Control,ANC)系统的空间平滑问题.传统的分布式ANC算法通过本地控制器之间的通信,可以大大提高系统稳定性.但由于每组控制器和误差麦克风分布位置不同,引入的估计偏差影响系统整体降噪性能.因此,旨在开发一种新型扩散滤波最小均方算法(Diffusion Filtered-x Least Mean Squares,Diff-FxLMS),该算法平衡了空间平滑度和信息交换强度之间的矛盾,从而减少估计偏差.通过对Diff-FxLMS算法性能进行的理论分析,揭示了扩散控制机制,为ANC算法设计提供了理论依据,并在此基础上发展出一种新型的可变平滑度的Diff-FxLMS(Varible Spatial Regularized Diff-FxLMS,VSR-Diff-FxLMS)算法.仿真结果验证了新算法的性能及理论分析的可靠性.
文摘Epignathus is an extremely rare congenital oropharyngeal teratoma.Here,we report a case of epignathus without intracranial extension in a fetus.The mass was first found by ultrasonography at 22 gestational weeks.Serial ultrasound examinations and magnetic resonance imaging confirmed that the fetus had neither central nervous system involvement nor abnormal nose or tooth.The baby was delivered at 37 weeks and six days of gestation via cesarean section set up for ex-utero intrapartum treatment.The postnatal pathologic examination confirmed the presence of mature tissues predominantly containing ectopic central nervous tissue,osseous tissue,and bronchial mucosal tissue.Most cases of epignathus are associated with malformation and death.Ultrasound and magnetic resonance imaging prenatal assessments are very important to facilitate counseling and understand prognosis.In conclusion,the ex-utero intrapartum treatment procedure is a good approach to improve the survival of infants with epignathus.
