二维 Lotka-Volterra 扩散系统一致持久的无害时滞

研究了二维Ｌｏｔｋａ－Ｖｏｌｔｅｒｒａ扩散系统中时滞对持久性的影响,证明时滞对该系统的一致持久性无害．所用技巧是时滞反应扩散系统的单调方法．     

一类风险证券有效组合的变动分析

研究了不相关风险证券在不允许卖空条件下,新增加证券对于原有有铲组合的影响及调整问题,分析了有效边界的变动和投资比例的变化,并给出了最小风险有效证券组合和最大收益有效证券组合的漂移距离与风险、收益及投资比例的增加或减少程度的关系。     

不确定性分布型时滞系统的鲁棒镇定

研究了一类更为广泛的具分布型滞后的不确定性系统的鲁棒镇定问题.首先给出了零输入情况下的状态渐近稳定的代数Riccati不等式型判据.并给出了标称系统镇定反馈控制器的设计方法.之后,讨论了具有分布型滞后的不确定性的控制系统.给出了其鲁棒镇定控制器的设计方法.     

差分Turbo-OFDM在短波数据通信中的应用研究

该文提出了将Turbo码与OFDM调制、差分检测技术相结合,分析了这种差分Turbo-OFDM体制在短波数据通信中的应用可能。该体制具有较高的频率利用率,可有效地抑制短波信道中多径时延、频率选择性衰落、人为干扰与噪声带来的不利影响。仿真结果显示该体制提高了短波信道上数据通信的误码性能。     

一类一阶中立型常系数微分方程振动的充分条件

本文研究了既有滞后量又有超前量的一阶中立型常系数微分方程的振动性,得到了其振动的几个充分条件。推广和改进了文[1]的部分结果。     

以滞量为参数的 Vanderpol型方程的 Hopf分支

本文以滞量为参数讨论了时滞 Ｖａｎ ｄｅｒ ｐｏｌ型方程的 Ｈｏｐｆ分支情况。     

立达清梳联短绒问题的研究

测试分析了立达清梳联生条短绒率偏高的主要原因及影响因素,通过工艺试验,优选了Ｃ４型梳棉机给棉刺辊部分的工艺参数．     

力觉临场感系统中的时延环节

利用力觉临场感遥控系统中传输环节的混合参数矩阵,证明了时延对整个系统的影响,描述了２种改善或消除时延影响的方法。针对实际系统进行了分析,得出了增大主操作器阻尼会增加稳定性,而增大从操作器阻尼会增加不稳定性的结论。     

Design of an anti-jamming GPS receiver based on orthogonal projection method

Code delay and Doppler shifted frequency could not be captured by using the conventional GPS receiver in strong interference environments because the received GPS signals which traveled a long distance are very weak. An anti-jamming GPS receiver is proposed. The interferences in the received signals are cancelled by using subspace projecting technique, and the resulting interference-free signals are processed by a weight vector which maximizes the signal-to-noise ratio. Simulation is conducted, and the resu...     

Adaptive broadband beamformer for nonuniform linear array based on second order cone programming

Adaptive broadband beamforming is a key issue in array applications. The adaptive broadband beamformer with tapped delay line (TDL) structure for nonuniform linear array (NLA) is designed according to the rule of minimizing the beamformer's output power while keeping the distortionless response (DR) in the direction of desired signal and keeping the constant beamwidth (CB) with the prescribed sidelobe level over the whole operating band. This kind of beamforming problem can be solved with the interior-point method after being converted to the form of standard second order cone programming (SOCP). The computer simulations are presented which illustrate the effectiveness of our bearaformer.