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1.
次级通道模型误差下滤波X型最小均方差算法收敛性分析   总被引:1,自引:0,他引:1  
给出了滤波X型LMS(FXLMS)算法收敛的一个充分条件,指出如果次级通道传递函数与其估计值在所有频带上满足正实条件,则FXLMS算法对任意参考信号收敛。若上述正实条件仅在某些频带上满足,则FXLMS算法的收敛将依赖于参考信号功率谱密度的分布。收敛步长取决于某特定相关矩阵特征值的分布。将上述结论应用于时延型LMS(DLMS)算法,得出在时延估计存在误差时,DLMS算法收敛于若干离散的频带,而频带宽度完全取决于“对延估计误差频率”(时延估计误差倒数的1/4)。  相似文献   

2.
时延估计技术及其在多途环境中的应用   总被引:12,自引:2,他引:10  
将Vaccaro等人提出的带惩罚函数的最小二乘算法和Li等人提出的WRELAX时延估计算法结合起来,给出了一种时延估计问题的混合算法,其中WMLAX算法用于计算重叠信号时延和幅度的初始值,带惩罚函数的频域最小二乘算法用于确定重叠信号时延和幅度的真实值。本文还介绍了利用相关系数进行时延估计运算以及确定有效多途信号数目的方法,并成功地运用到实验数据处理。模拟数据显示混合算法具有很强的处理重叠多途信号,以及抗噪声干扰的能力。对实验获得的时带积(TB)为 800,带宽从 500 Hz到 700 Hz的线性调频(LFM)信号,利用相关系数获得的重构接收信号与接收信号符合得非常好。  相似文献   

3.
自由声场至耳膜的传递函数(FETF)被认为是影响辨别声源方向的主要因素之一。FETF已被用于真实听觉空间的计算机仿真。对于FETF的估计和测量方法,本文提出了具体的改进意见。对于单脉冲激励的测量方法,我们建议采用LMS估计方法,计算机模拟结果表明LMS方法优于经典的FFT方法。文章中还对各种用于测量FETF冲激响应的激励方法作了分析和比较。  相似文献   

4.
THE EXCESS HEAT EXPERIMENTS ON COLD FUSION IN TITANIUM LATTICETHEEXCESSHEATEXPERIMENTSONCOLDFUSIONINTITANIUMLATTICE¥ZhangQing...  相似文献   

5.
EFFECTOFRADIALELECTRICALFIELDONNEOCLASSICALTRANSPORTINTOKAMAKSEFFECTOFRADIALELECTRICALFIELDONNEOCLASSICALTRANSPORTINTOKAMAKS¥...  相似文献   

6.
不同注量X射线系统电磁脉冲响应的数值计算   总被引:3,自引:0,他引:3  
周辉  李宝忠 《计算物理》1999,16(2):157-157
对X射线在铝制圆柱形模型上产生的系统电磁脉冲现象进行数值计算,采用了二维粒子模拟技术,得到了8个量级范围的X线入射线入射注量下的SGEMP计算结果,总结了SGEMP的场值,分布与X光注量的变化规律。  相似文献   

7.
TOTALCROSSSECTIONMEASUREMENTSFORELECTRONSCATTERINGONMETHANEBETWEEN1AND50eVLiTaihuaYeRuiyingYangYongCenterforRadiationPhysics...  相似文献   

8.
MEASUREMENTSOFFeANDCuK-ShelIONIZATIONCROSSSECTIONSBYSLOWELECTRONIMPACTLiTaihuaAnZhuLuoZhengmingCenterforRadiationPhysics,Ins...  相似文献   

9.
基于最小均方差估计的非线性IEM模型   总被引:1,自引:0,他引:1  
本文根据统计学中的最小均方差估计理论推导出非线性的IEM(NLIEM)模型公式,并综合实验数据确定了模型系数.这个模型考虑了标量场大尺度运动非均匀性,Re数以及Sc数对混合速率的影响.最后分别利用NLIEM和IEM模型对H2/空气湍流射流扩散火焰进行了计算,与实验结果的比较表明新模型有较大的优越性.  相似文献   

10.
使用HREELS,XPS及TDS在室温下考察了氧吸附Fe(110)上的CO吸附态,观察到了振动频率为2120cm^-1的CO弱吸附态,3种检测手段的结果相互支持。  相似文献   

11.
一种菲涅尔全息图的快速算法   总被引:1,自引:1,他引:0  
李勇  许富洋  金洪震  王辉 《光子学报》2010,39(3):529-532
通过分析菲涅尔全息图计算模型,发现大量的平方运算和三角函数运算是计算速度的瓶颈,提出了一种菲涅尔全息图的快速计算方法.根据菲涅尔全息图的数学模型,利用三角函数的和差化积公式,将全息图的数学模型变换为由仅与水平或垂直方向有关的独立分量,通过四则运算来表示.在菲涅尔全息图的计算中,用少量的三角函数、平方运算和大量的四则运算代替原来大量的三角函数和平方运算,减少了全息图的运算量.实验表明,采用该算法后全息图的计算速度提高了9倍以上.  相似文献   

12.
The design variable tolerance effects on the natural frequency variance of constrained multi-body systems in dynamic equilibrium are investigated in this study. Monte-Carlo simulation is often employed for such investigations, but it is known to have serious drawbacks. Excessive amount of computation time needs to be consumed since a large number of evaluations are usually required for the method. Furthermore, the solution accuracy cannot be always guaranteed in spite of the excessive amount of computation time. In order to overcome such drawbacks, a method employing eigenvalue sensitivity information is proposed to obtain the variance of natural frequency in this study. In order to verify the accuracy and the efficiency of the method, some numerical examples of multi-body systems in dynamic equilibrium are solved and the results are compared to those obtained by an analytical method and Monte-Carlo simulation.  相似文献   

13.
发展了一种三维有限元数值模型和计算方法来对矩形流管声场进行整体的计算.与以往的二维方法相比,此种数值方法不仅全面反映了矩形流管内声波的传播情况,而且提高了网格精度,从而大大扩展了对铺设有声衬的流管的计算领域.结果表明,该数值模型是有效和准确的,与其它方法和文献的计算结果吻合得非常好.同时,在大大增加计算量的同时,也对程序代码进行了优化工作,提高了计算效率.  相似文献   

14.
For the multi-frequency acoustic analysis, a series expansion method has been introduced to reduce the computation time of the frequency-independent parts, but the Runge phenomenon will arise when this method is employed in high frequency band. Therefore, this method is improved by analyzing the application condition and proposing the selection principle of the series truncation number. The argument interval can be adjusted with the wavenumber factor. Therefore, the problem of unstable numeration and poor precision can be solved, and the application scope of this method is expanded. The numerical example of acoustic radiation shows that the improved method is correct for acoustic analysis in wider frequency band with less series truncation number and computation amount.  相似文献   

15.
The method of large particles, which is applied in one-dimensional numerical simulation of processes in electron devices, such as traveling-wave tubes, is suggested. With the number of large particles fixed, the amount of computation remains virtually the same, while the accuracy attained under strong nonlinearity rises significantly.  相似文献   

16.
本文介绍傅氏声强测量中,用几何平均声压代替算术平均声压,可以减少计算工作量.并从理论上证明了两者之间的差异可以忽略,因此可以保证声压测量的精度.  相似文献   

17.
王振坤  顾祥龙  曹锐 《强激光与粒子束》2019,31(11):113002-1-113002-8
利用物理光学法计算了高功率微波在建筑物内的耦合场分布。根据建筑物墙壁和窗户的透射率可以得到墙壁内侧的透射场,将它代入到矢量衍射公式中直接计算出在整个建筑物内的透射场;根据建筑物地面的反射率得到地板表面的反射场,将它代入到矢量衍射公式中可计算出整个建筑物内的反射场;对透射场与反射场进行矢量相加,得到叠加场。将本文方法得到的场分布情况和时域有限差分法得到的场分布进行比较,二者结果一致。物理光学法的优点在于其物理图像清晰,计算量小,计算速度快,适合应用在大型建筑物内部耦合场分布计算上。  相似文献   

18.
We present a classical protocol to efficiently simulate any pure-state quantum computation that involves only a restricted amount of entanglement. More generally, we show how to classically simulate pure-state quantum computations on n qubits by using computational resources that grow linearly in n and exponentially in the amount of entanglement in the quantum computer. Our results imply that a necessary condition for an exponential computational speedup (with respect to classical computations) is that the amount of entanglement increases with the size n of the computation, and provide an explicit lower bound on the required growth.  相似文献   

19.
Finline plays an important role in millimeter-wave integrated-circuit design. In this paper, a knowledge-based artifcial neural network is used to model the finline. Using prior knowledge input method and Bayesian regularization technique make the neural network models for finline reduce the amount of training data needed and prevent overfitting in neural network training. The neural network is electromagnetically developed with a set of training data that are produced by the fnite element method, which is robust both from the angle of time of computation and accuracy.  相似文献   

20.
Selective image encryption has been considered as an effective method to improve the encryption speed and computation resource by reducing considerable amount of data. In the present paper, the weaknesses of recent method of selective image encryption are presented analytically and the method of security improvement is proposed. The security for selective image encryption is improved in a way that number of selectively significant bits for encryption vary from pixel to pixel. This leads to be uncertain data for encryption and decryption. The examples are to demonstrate and verify for security weaknesses of the recent method and the effectiveness of the proposed method.  相似文献   

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