A novel text independent speaker identification system is proposed. In the proposed system, the 12-order perceptual linear predictive cepstrum and their delta coefficients in the span of five frames are extracted from...A novel text independent speaker identification system is proposed. In the proposed system, the 12-order perceptual linear predictive cepstrum and their delta coefficients in the span of five frames are extracted from the segmented speech based on the method of pitch synchronous analysis. The Fisher ratios of the original coefficients then be calculated, and the coefficients whose Fisher ratios are bigger are selected to form the 13-dimensional feature vectors of speaker. The Gaussian mixture model is used to model the speakers. The experimental results show that the identification accuracy of the proposed system is obviously better than that of the systems based on other conventional coefficients like the linear predictive cepstral coefficients and the Mel-frequency cepstral coefficients.展开更多
针对高速无人飞行器视距测控通信的抗干扰、抗截获、中低速数据传输以及高动态环境下的快速捕获需求,提出一种实用的突发码移键控扩频(CSK/SS)通信系统方案。详细介绍了系统的帧结构设计、调制算法、解调算法和同步算法,给出优化的实现...针对高速无人飞行器视距测控通信的抗干扰、抗截获、中低速数据传输以及高动态环境下的快速捕获需求,提出一种实用的突发码移键控扩频(CSK/SS)通信系统方案。详细介绍了系统的帧结构设计、调制算法、解调算法和同步算法,给出优化的实现方案。仿真及试验表明,该系统支持低信噪比(-9 dB)、大动态多普勒频移(±31 k Hz)条件下最高200 kbps的信息传输,是一种可靠的高速扩频实现方案。展开更多
A pre-processing procedure is designed for a space-surface bistatic synthetic aperture radar （SS-BSAR） system when a time domain image formation algorithm is employed. Three crucial technical issues relating to the ...A pre-processing procedure is designed for a space-surface bistatic synthetic aperture radar （SS-BSAR） system when a time domain image formation algorithm is employed. Three crucial technical issues relating to the procedure are fully discussed. Firstly, unlike image formation algorithms operating in the frequency domain, a time domain algorithm requires the accurate global navigation satellite system （GNSS） time and position. This paper proposes acquisition of this information using a time-and-spatial transfer with precise ephemeris and interpolation. Secondly, synchronization errors and compensation methods in SS-BSAR are analyzed. Finally, taking the non-ideal factors in the echo and the compatibility of image formation algorithms into account, a matched filter based on the minimum delay is constructed. Experimental result using real data suggest the pre-processing is functioning properly.展开更多
Through analyzing the special starting process and the factors which affect the starting torque of the low-speed synchronous motor, a testing method of the starting torque is proposed, and the defects of the existing ...Through analyzing the special starting process and the factors which affect the starting torque of the low-speed synchronous motor, a testing method of the starting torque is proposed, and the defects of the existing hand-test method is analyzed. Moreover, an automatic testing apparatus of this special kind of motors is introduced.展开更多
提出了一款基于扰动观测器的分数阶比例-积分-微分(Perturbation observer based Fractional-order Proportional-Integral-Derivative,PoFoPID)控制策略,以在永磁同步发电机(Permanent Magnetic Synchronous Generator,PMSG)高于额定...提出了一款基于扰动观测器的分数阶比例-积分-微分(Perturbation observer based Fractional-order Proportional-Integral-Derivative,PoFoPID)控制策略,以在永磁同步发电机(Permanent Magnetic Synchronous Generator,PMSG)高于额定风速的工况下,通过变桨距角控制,将发电机输出功率维持在其额定值附近。首先,将PMSG的系统非线性、参数不确定性和未建模动态等聚合为新的扰动,并采用扰动观测器对其进行在线估计。然后,设计分数阶PID控制对该扰动估计进行实时完全补偿,以提高系统动态特性。此外,PoFoPID控制器参数通过群天牛算法寻优获得,避免了常规PID控制参数依赖人工整定的缺陷。斜坡风速、随机风速和参数不确定算例下的仿真结果表明,与矢量控制、基于扰动观测器的PID控制和反馈线性化控制相比,所提PoFoPID控制具有满意的输出功率稳定效果。最后,基于dSpace进行的硬件在环实验(Hardware-in-loop,HIL)验证了所提方法的硬件可行性。展开更多
文摘A novel text independent speaker identification system is proposed. In the proposed system, the 12-order perceptual linear predictive cepstrum and their delta coefficients in the span of five frames are extracted from the segmented speech based on the method of pitch synchronous analysis. The Fisher ratios of the original coefficients then be calculated, and the coefficients whose Fisher ratios are bigger are selected to form the 13-dimensional feature vectors of speaker. The Gaussian mixture model is used to model the speakers. The experimental results show that the identification accuracy of the proposed system is obviously better than that of the systems based on other conventional coefficients like the linear predictive cepstral coefficients and the Mel-frequency cepstral coefficients.
文摘针对高速无人飞行器视距测控通信的抗干扰、抗截获、中低速数据传输以及高动态环境下的快速捕获需求,提出一种实用的突发码移键控扩频(CSK/SS)通信系统方案。详细介绍了系统的帧结构设计、调制算法、解调算法和同步算法,给出优化的实现方案。仿真及试验表明,该系统支持低信噪比(-9 dB)、大动态多普勒频移(±31 k Hz)条件下最高200 kbps的信息传输,是一种可靠的高速扩频实现方案。
基金supported by the Electro-Magnetic Remote Sensing Defence Technology Centre (EMRS-DTC) of the UK Ministry of Defence(EMRS/DTC/1/27)the China Scholarship Council (2009611064)the Program for New Century Excellent Talents in University (NCET-07-0223)
文摘A pre-processing procedure is designed for a space-surface bistatic synthetic aperture radar （SS-BSAR） system when a time domain image formation algorithm is employed. Three crucial technical issues relating to the procedure are fully discussed. Firstly, unlike image formation algorithms operating in the frequency domain, a time domain algorithm requires the accurate global navigation satellite system （GNSS） time and position. This paper proposes acquisition of this information using a time-and-spatial transfer with precise ephemeris and interpolation. Secondly, synchronization errors and compensation methods in SS-BSAR are analyzed. Finally, taking the non-ideal factors in the echo and the compatibility of image formation algorithms into account, a matched filter based on the minimum delay is constructed. Experimental result using real data suggest the pre-processing is functioning properly.
文摘Through analyzing the special starting process and the factors which affect the starting torque of the low-speed synchronous motor, a testing method of the starting torque is proposed, and the defects of the existing hand-test method is analyzed. Moreover, an automatic testing apparatus of this special kind of motors is introduced.
文摘提出了一款基于扰动观测器的分数阶比例-积分-微分(Perturbation observer based Fractional-order Proportional-Integral-Derivative,PoFoPID)控制策略,以在永磁同步发电机(Permanent Magnetic Synchronous Generator,PMSG)高于额定风速的工况下,通过变桨距角控制,将发电机输出功率维持在其额定值附近。首先,将PMSG的系统非线性、参数不确定性和未建模动态等聚合为新的扰动,并采用扰动观测器对其进行在线估计。然后,设计分数阶PID控制对该扰动估计进行实时完全补偿,以提高系统动态特性。此外,PoFoPID控制器参数通过群天牛算法寻优获得,避免了常规PID控制参数依赖人工整定的缺陷。斜坡风速、随机风速和参数不确定算例下的仿真结果表明,与矢量控制、基于扰动观测器的PID控制和反馈线性化控制相比,所提PoFoPID控制具有满意的输出功率稳定效果。最后,基于dSpace进行的硬件在环实验(Hardware-in-loop,HIL)验证了所提方法的硬件可行性。
