高阶间隔估计算法在网络流量监测中的应用研究

当前的网络流量监测方法比如报文抽样和时间间隔抽样,存在资源消耗大和精度低2个方面的问题,本文提出了一种高带宽及高传输速率情况下的流量监测方法,即以均匀分组采样方法为理论的高阶间隔估计算法﹒首先根据网络流量的动态变化,实时调整采样次数;再利用低阶采样数据及优化算法进行高阶估计;最后采用相对熵进行采样性能分析与估计﹒仿真结果表明,随着高阶间隔的逐渐增大,流量监测的精度相比报文采样和时间间隔采样得到逐步提高,而资源消耗却显著减少﹒

无线电信号的高阶谱估计分析

随着无线电行业的迅速发展,无线电信号的频谱分析应用得到广泛应用。在现代信号处理中,现代谱估计法利用参数化模型来进行谱估计,大大地提高了功率谱估计的分辨率。本文使用高阶谱估计提高信号分辨率,在MATLAB上验证,并通过双谱和三维双谱对信号的仿真,可以发现信号较强的频率分布区域——信号抗噪声能力越强,双谱图中等高线分布越集中。

基于高阶谱法作物重金属污染元素判别与污染程度诊断

基于不同铜离子(Cu^(2+))和铅离子(Pb^(2+))胁迫梯度下玉米叶片光谱微分数据,结合高阶谱估计与灰度-梯度共生矩阵(Gray gradient co-occurrence matrix,GGCM)的特征提取方法,提出了Cu^(2+)和Pb^(2+)污染定性分析、污染元素种类识别和污染程度诊断的方法。首先,测量了不同胁迫梯度下玉米叶片光谱数据以及叶片中富集的Cu^(2+)、Pb^(2+)含量;然后,利用高阶谱估计的ARMA模型参数法对各类玉米叶片微分光谱数据序列进行双谱估计,得到bisp_rts和bisp_qs矩阵及其相应的双谱三维图,从而可以直观可视地定性分析玉米是否已受Cu^(2+)和Pb^(2+)污染,辨别出Cu^(2+)或Pb^(2+)污染的元素类别;最后,构造bisp_rts和bisp_qs矩阵相应的GGCM,通过提取各GGCM的纹理参量特征值,诊断玉米叶片受Cu^(2+)和Pb^(2+)的污染程度。实验结果表明:高阶谱估计可以定性分析玉米老叶(O)、中叶(M)、新叶(N)是否已受Cu^(2+)和Pb^(2+)污染,也可辨别出O、M叶片所受Cu^(2+)或Pb^(2+)污染的元素类别;bisp_rts矩阵的灰度分布不均匀性(T1)、能量(T2)特征值均能反映O、M叶片中Pb^(2+)含量的变化,能较好地诊断O、M叶片中Pb^(2+)的污染程度,而bisp_qs矩阵的小梯度优势(T3)特征值能反映O、M叶片中Cu^(2+)含量的变化,能较好地诊断O、M叶片中Cu^(2+)的污染程度。

基于高阶累计量的车辆上下行声频检测方法

提出了一种基于麦克风阵列信号处理的车辆上下行估计的新方法,将车辆的上下行估计归结为阵列信号处理中的波达方向变化的估计。针对车辆噪声信号的复杂性和二阶统计量的局限性,采用高阶累计量实现了DOA估计,并说明了基于高阶累计量实现的估计结果明显优于二阶统计量。最后通过试验论证了该方法在实现行车方向估计时的有效性。

Fast global motion estimation and moving object extraction algorithm in image sequences

A novel and effective approach to global motion estimation and moving object extraction is proposed. First, the translational motion model is used because of the fact that complex motion can be decomposed as a sum of translational components. Then in this application, the edge gray horizontal and vertical projections are used as the block matching feature for the motion vectors estimation. The proposed algorithm reduces the motion estimation computations by calculating the onedimensional vectors rather than the two-dimensional ones. Once the global motion is robustly estimated, relatively stationary background can be almost completely eliminated through the inter-frame difference method. To achieve an accurate object extraction result, the higher-order statistics （HOS） algorithm is used to discriminate backgrounds and moving objects. Experimental results validate that the proposed method is an effective way for global motion estimation and object extraction.

脑干听觉诱发电位的频域特征分析

本文利用功率谱估计及高阶谱估计的技术对听觉诱发电位的特征进行了研究 ,确定了诱发电位信号有效带宽和各频段的功率分布 ,提出采用谱估计方法进行BAEP特征识别的有效性。

癫痫脑电的双谱特性研究

双谱分析对于分析处理非高斯、非线性随机信号具有明显优点。脑电信号被认为具有非高斯、非线性的特性。本文对不同发作阶段癫痫患者的脑电信号进行双谱估计 ,进而研究不同生理条件下脑电的双谱特性。结果表明 ,不同发作阶段时癫痫脑电信号的高斯偏离程度明显不同 ,其中双相干系数能够区分不同发作阶段脑电的信号特征 。

Frequency Domain TOA Estimation Algorithm Based on Cross-HOC

High-Order Cumulants （HOC） and cross-correlation was combined to suppress the Gaussian color noises and the tin-related noises in real applications. The cross-HOC TOA estimation model was developed based on the diagonal slice of the forth-cross-cumu-lant. The eigen analysis was carried out, and the eigea noise space and the eigen signal space was achieved. Then the Frequency Domain TOA estimation algorithm based on Cross-HOC was developed. Different simulation experiments were carried out to draw out the conclusions.

线性规划内点法中拉格朗日乘子的估计

一、引言 我们考虑以下的线性规划问题:

A Note on Schwarz-Pick Estimate

A Schwarz-Pick estimate of higher order derivative for holomorphic functions with positive real part on Bn is presented. This improves the earlier work on Schwarz-Pick estimate of higher order derivatives for holomorphic functions with positive real part on the unit disk in C.

Higher-Order Schwarz-Pick Estimates for Holomorphic Self-mappings on Classical Domains

In this paper, Schwarz-Pick estimates for high order FrSchet derivatives of holo- morphic self-mappings on classical domains are presented. Moreover, the obtained result can deduce the early work on Sc：hwarz-Pick estimates of higher-order partial derivatives for bounded holomorphic functions on classical domains.

Hyperpolarizabilities of alkaline-earth metal ions Be^+, Mg^+, and Ca^+

The knowledge of the hyperpolarizabilities of atoms and ions is helpful for the analysis of the high order effects of the frequency shifts in precision spectroscopy experiments. Liu et al. [Phys. Rev. Lett. 114, 223001 （2015）] proposed to establish all-optical trapped ion clocks using laser at the magic wavelength for clock transition. To evaluate the high-order frequency shifts in this new scheme of optical clocks, hyperpolarizabilities are needed, but absent. Using the finite field method based on the B-spline basis set and model potentials, we calculated the electric-field-dependent energy shifts of the ground and low-lying excited states in Be＋, Mg＋, and Ca＋ in the field strength range of 0.0-6×10-5 a.u.. The scalar and tensor polarizabilities （α0, α2） and hyperpolarizabilities （Y0,Y2, 74） were deduced. The results of the hyperpolarizabilities for Be＋ showed good agreement with the values in literature, implying that the present method can be applied for the effective estimation of the atomic hyperpolarizabilities, which are rarely reported but needed in experiments. The feasibility of optical trapping of Ca＋ is discussed, and the contributions of hyperpolarizabilities to the transition frequency shift for Ca＋ in the optical dipole trap are estimated using quasi-electrostatic approximation.

Strichartz estimates for parabolic equations with higher order differential operators

The present paper first obtains Strichartz estimates for parabolic equations with nonnegative elliptic operators of order 2m by using both the abstract Strichartz estimates of Keel-Tao and the Hardy-LittlewoodSobolev inequality. Some conclusions can be viewed as the improvements of the previously known ones. Furthermore, an endpoint homogeneous Strichartz estimates on BMOx(Rn) and a parabolic homogeneous Strichartz estimate are proved. Meanwhile, the Strichartz estimates to the Sobolev spaces and Besov spaces are generalized. Secondly, the local well-posedness and small global well-posedness of the Cauchy problem for the semilinear parabolic equations with elliptic operators of order 2m, which has a potential V(t, x) satisfying appropriate integrable conditions, are established. Finally, the local and global existence and uniqueness of regular solutions in spatial variables for the higher order elliptic Navier-Stokes system with initial data in Lr(Rn) is proved.

High-Order Energy Decay for Structural Damped Systems in the Electromagnetical Field

This paper is concerned with the decay estimate of high-order energy for a class of special time-dependent structural damped systems represented by Fourier multipliers. This model is widely used in the fields of semiconductivity, superconductivity, electromagnetic waves, electrolyte and electrode materials, etc.