Joint asymptotic distributions of maximas for multi-variate normal process

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Effect of normalizing cooling process on microstructure and precipitates in low-temperature silicon steel

Microstructure, precipitate and magnetic characteristic of fmal products with different normalizing cooling processes for Fe-3.2%Si low-temperature hot-rolled grain-oriented silicon steel were analyzed and compared with the hot-rolled plate by optical microscopy （OM）, transmission electron microscopy （TEM）, and energy dispersive spectrometry （EDS）. The results show that, the surface microstructure is uniform, the proportion of recrystallization in matrix increases, and the banding textures are narrowed; the precipitates, whose quantity in normalized plate is more than that in hot-rolled plate greatly, are mainly A1N, MnS, composite precipitates （Cu,Mn）S and so on. Normalizing technology with a temperature of 1120 ℃, holding for 3 min, and a two-stage cooling is a most advantaged method to obtain oriented silicon steel with sharper Goss texture and higher magnetic properties, owing to the uniform surface microstructures and the obvious inhomogeneity of microstructures along the thickness. The normalizing technology with the two-stage cooling is the optimum process, which can generate more fine precipitates dispersed over the matrix, and be beneficial for finished products to get higher magnetic properties.

Evaluation of Two Absolute Radiometric Normalization Algorithms for Pre-processing of Landsat Imagery

In order to evaluate radiometric normalization techniques, two image normalization algorithms for absolute radiometric correction of Landsat imagery were quantitatively compared in this paper, which are the Illumination Correction Model proposed by Markham and Irish and the Illumination and Atmospheric Correction Model developed by the Remote Sensing and GIS Laboratory of the Utah State University. Relative noise, correlation coefficient and slope value were used as the criteria for the evaluation and comparison, which were derived from pseudo-invarlant features identified from multitemporal Landsat image pairs of Xiamen （厦门） and Fuzhou （福州） areas, both located in the eastern Fujian （福建） Province of China. Compared with the unnormalized image, the radiometric differences between the normalized multitemporal images were significantly reduced when the seasons of multitemporal images were different. However, there was no significant difference between the normalized and unnorrealized images with a similar seasonal condition. Furthermore, the correction results of two algorithms are similar when the images are relatively clear with a uniform atmospheric condition. Therefore, the radiometric normalization procedures should be carried out if the multitemporal images have a significant seasonal difference.

Symmetry Violation of Time Reversal in Third Order Vertex Angle Renormalization Process of Electromagnetic Interaction

According to the current understanding, electromagnetic interaction is invariable under time reversal. However, the proof of time reversal symmetry in quantum theory of field has not considered the effects of high order perturbation normalizations. It is proved in the paper that when the renormalization effect of third order vertex angles process is taken into account, the symmetry of time reversal will be violated in electromagnetic interaction process. Because the magnitude order of symmetry violation is about 10–5, but the precision of current experiments on time reversal in particle physics is about 10–3, this kind of symmetry violation can not be found. The result reveals the micro-origin of asymmetry of time reversal and can be used to solve the famous irreversibility paradox in the evolution processes of macro- material systems.

基于Poisson-Normal过程性能退化模型的可靠性分析

对于高可靠长寿命产品,基于性能退化数据分析产品可靠性是一种行之有效的技术途径。由于有时无法用确定的物理/化学过程定量描述性能退化过程,借助随机过程方法建立退化模型是有效的技术途径。提出了基于Poisson-Normal过程的性能退化模型,给出了参数估计算法和可靠性估计的计算公式,结合实例说明了方法的有效性。

小子样条件下基于Normal-Poisson过程的性能可靠性评定

对于高可靠、长寿命产品,基于性能退化数据分析可靠性是一种行之有效的技术途径。结合航空航天产品性能退化的机理与现场试验小子样的特点,建立了基于Normal-Poisson过程的性能退化模型。论文在对产品性能退化建模的基础上,结合Bayes方法给出了退化模型参数的估计算法和可靠性推断的公式,最后结合实例说明了方法的有效性。

Research of the Adaptive Beamformer Based on the Frequency Energy Normalization

An algorithm of broadband minimum variance distortionless response(MVDR) based on the frequency energy normalization is proposed.First,every narrowband frequency component of the broadband signal is normalized by the total narrowband energy of all array elements,and the narrowband power is calculated by MVDR.Finally,final spatial energy spectrum can be obtained by averaging or summing all results of every narrowband frequency bin.Any prior-information about the noise or the signal is unnecessary for the proposed method in this paper.The processing gain of the proposed method compared to the conventional broadband MVDR can be obtained as long as the amplitude fluctuation of the array noise frequency spectrum is severer than that of the target signal.The validity of the method is validated by the optimal signal detection theory.Simulation and real data are used to validate the performance of the method.Analysis results show that about 4 dB processing gain compared to the general broadband MVDR can be reached by the proposed method.

1991~2020年中国地面气候值数据集研制

基于国家气象信息中心归档的中国地面观测数据,研制了1991~2020年中国地面气候值数据集。数据集研制期间,对1991年以来的地面台站观测数据集元数据进行了系统的质量检查和核实订正。在基于站址迁移信息对所有要素进行了分段处理基础上,基于非均一性检验结果完成了气温序列的分段处理。依据人工、自动观测调整信息完成了能见度观测数据的分段处理,提供了一套与当前能见度观测方式一致、代表性更好的气候背景场。采用傅里叶级数理论对气温、降水累年日值序列进行了谐波处理,在体现气象变量季节性转换的同时,避免了日与日之间的异常突变特征,具有更好的气候代表性。最终建立的1991~2020年中国地面气候值数据集提供了中国2438个站点的气温、降水、气压、风向风速、相对湿度、水汽压、云、天气现象、能见度、蒸发、积雪、地温、冻土、日照共14个要素的气候背景信息,为天气气候业务提供了数据支撑。

From Nonparametric Density Estimation to Parametric Estimation of Multidimensional Diffusion Processes

The paper deals with the estimation of parameters of multidimensional diffusion processes that are discretely observed. We construct estimator of the parameters based on the minimum Hellinger distance method. This method is based on the minimization of the Hellinger distance between the density of the invariant distribution of the diffusion process and a nonparametric estimator of this density. We give conditions which ensure the existence of an invariant measure that admits density with respect to the Lebesgue measure and the strong mixing property with exponential rate for the Markov process. Under this condition, we define an estimator of the density based on kernel function and study his properties (almost sure convergence and asymptotic normality). After, using the estimator of the density, we construct the minimum Hellinger distance estimator of the parameters of the diffusion process and establish the almost sure convergence and the asymptotic normality of this estimator. To illustrate the properties of the estimator of the parameters, we apply the method to two examples of multidimensional diffusion processes.

On the Use of Second and Third Moments for the Comparison of Linear Gaussian and Simple Bilinear White Noise Processes

The linear Gaussian white noise process (LGWNP) is an independent and identically distributed (iid) sequence with zero mean and finite variance with distribution . Some processes, such as the simple bilinear white noise process (SBWNP), have the same covariance structure like the LGWNP. How can these two processes be distinguished and/or compared? If is a realization of the SBWNP. This paper studies in detail the covariance structure of . It is shown from this study that;1) the covariance structure of is non-normal with distribution equivalent to the linear ARMA(2, 1) model;2) the covariance structure of is iid;3) the variance of can be used for comparison of SBWNP and LGWNP.

基于改进SVM的电力工程造价预测

针对支持向量机求解速度较慢且用于预测电力工程造价的性能不理想等问题,提出了一种基于改进SVM的电力工程造价预测模型。该模型全面考虑了电力工程成本的组成要素并进行参数归一化处理,利用最小二乘估计改进SVM模型,同时采用遗传算法求解LSSVM的参数最优值,并通过优化后的GA-LSSVM模型实现对电力工程成本的预测。基于MATLAB仿真平台的仿真实验结果表明,模型预测的工程成本与实际值较为接近,归一化均方误差与平均绝对百分比误差分别为18.34万元和3.58%,且预测时间仅为256 ms,证明了其整体性能优于其他对比模型。

A weak invariance principle for self-normalized products of sums of mixing sequences

Let variables in the {X, Xn, n ≥ 1} be a sequence of strictly stationary φ-mixing positive random domain of attraction of the normal law. Under some suitable conditions the principle for self-normalized products of partial sums is obtained.

On the Functional Empirical Process and Its Application to the Mutual Influence of the Theil-Like Inequality Measure and the Growth

We set in this paper a coherent theory based on functional empirical processes that allows to consider both the poverty and the inequality indices in one Gaussian field in which the study of the influence of the one over the other is done. We use the General Poverty Index (GPI), that is a class of poverty indices gathering the most common ones and a functional class of inequality measures including the Entropy Measure, the Mean Logarithmic Deviation, the different inequality measures of Atkinson, Champernowne, Kolm and Theil called Theil-Like Inequality Measures (TLIM). Our results are given in a unified approach with respect to the two classes instead of their particular elements. We provide the asymptotic laws of the variations of each class over two given periods and the ratio of the variation and derive confidence intervals for them. Although the variances may seem somehow complicated, we provide R codes for their computations and apply the results for the pseudo-panel data for Senegalwith a simple analysis.

Event Normalization Through Dynamic Log Format Detection

The analytical and monitoring capabilities of central event re-positories, such as log servers and intrusion detection sys-tems, are limited by the amount of structured information ex-tracted from the events they receive. Diverse networks and ap-plications log their events in many different formats, and this makes it difficult to identify the type of logs being received by the central repository. The way events are logged by IT systems is problematic for developers of host-based intrusion-detection systems （specifically, host-based systems）, develop-ers of security-information systems, and developers of event-management systems. These problems preclude the develop-ment of more accurate, intrusive security solutions that obtain results from data included in the logs being processed. We propose a new method for dynamically normalizing events into a unified super-event that is loosely based on the Common Event Expression standard developed by Mitre Corporation. We explain how our solution can normalize seemingly unrelat-ed events into a single, unified format.

Some Applications of Higher Moments of the Linear Gaussian White Noise Process

The Linear Gaussian white noise process is an independent and identically distributed (iid) sequence with zero mean and finite variance with distribution N (0, σ2 ) . Hence, if X1, x2, …, Xn is a realization of such an iid sequence, this paper studies in detail the covariance structure of X1d, X2d, …, Xnd, d=1, 2, …. By this study, it is shown that: 1) all powers of a Linear Gaussian White Noise Process are iid but, not normally distributed and 2) the higher moments (variance and kurtosis) of Xtd, d=2, 3, … can be used to distinguish between the Linear Gaussian white noise process and other processes with similar covariance structure.

京大戟醋制前后对正常大鼠毒性的研究

目的比较京大戟醋制前后对正常大鼠肝、胃、肠、肾毒性的差异。方法采用雄性SD大鼠56只,随机分为7组:空白组、京大戟低、中、高剂量组和醋京大戟低、中、高剂量组。给药组大鼠分别灌胃0.253 g/kg、0.506 g/kg、1.012 g/kg京大戟、醋京大戟粉末,空白组灌胃等量的0.5%羧甲基纤维素钠,连续7天。考察给药后各组大鼠各脏器的组织病理形态学变化,测定血清中的肝肾功能指标及血清和组织中的氧化损伤指标。结果与空白组比较,各给药组大鼠肝、胃、肠病理切片可见不同程度的组织损伤,京大戟各剂量组的大鼠血清中谷丙转氨酶(alanine aminotransferase,ALT)与谷草转氨酶(aspartate transaminase,AST)活性显著升高(P<0.01,P<0.05),肌酐(creatinine,CRE)与尿素氮(blood urea nitrogen,BUN)活性略有升高;血清和肝、胃、肠组织中的超氧化歧化酶(superoxide dismutase,SOD)和谷胱甘肽(glutathione,GSH)含量明显降低,丙二醛(malondialdehyde,MDA)含量显著升高(P<0.01,P<0.05)。与京大戟组比较,醋京大戟组的大鼠肝、胃、肠组织损伤较轻,血清中AST、ALT活性显著降低;血清和肝、胃、肠组织中的MDA含量明显降低,SOD和GSH含量明显升高(P>0.05),但两组间无显著性差异。结论京大戟对正常大鼠肝、胃、肠毒性明显,对肾无明显损伤,醋制后毒性均下降,其毒性作用与氧化损伤相关。

实施理论——常态化过程理论的解读

目的 常态化过程理论(Normalization Process Theory,NPT)是实施研究中常用的理论之一,但较难理解。本文将详细介绍NPT,为研究者理解NPT提供指引。方法 通过检索与NPT理论相关的文献并结合团队实际使用NPT的体验,描述NPT的起源、开发与演变、核心要素解读、运用并讨论其特点。结果 NPT以新技术在日常工作中的嵌入(即常态化)为实施结局,指出这个结局是实施者、实施对象和实施环境相互作用的过程。经过20余年的演变,NPT最终包含4个维度和16个构念。结论 NPT逐步完善,为实施科学提供了重要的理论基础;但NPT比较抽象,且存在逻辑和概念的不足,研究者需要在透彻了解其含义的基础上灵活使用。

基于DWA算法的配网作业机器人避障路径规划

配网作业机器人运行环境中存在不同大小的障碍物,作业过程中会出现路径冗余问题,导致配网作业机器人避障能力差,为此提出基于DWA算法的配网作业机器人避障路径规划方法。根据机器人质量、车轮半径和轮间距信息构建机器人运动学模型,描述机器人在不同时刻的位姿;确定机器人作业空间,结合起点与目标点位置构建局部地图,约束机器人运动范围;设计DWA算法的速度向量空间,多采样机器人速度,获取限速区域,在该区间内生成多条待选择的路径;利用方向评价、障碍物距离评价和速度评价3个子函数组成DWA评价函数,分别对子函数做归一化处理,选取评价值最高的路径作为最优避障规划路径。实验结果表明,该方法在简单和复杂的作业环境下均能准确避障,且路径最短。

基于GMM-Ada-LASSO模型的高维过程统计质量监控方法

针对高维数据往往不服从正态分布导致统计监控模型识别精度低、监控效率差的问题,文章提出一种基于高斯混合模型的变量选择控制图方法。首先,利用高斯混合模型将高维过程分解成若干个服从正态分布的子分布;然后,运用Adaptive LASSO算法识别潜在异常变量;最后,构建多元EWMA控制图实现高维过程统计质量监控。通过仿真实验,在六种不同情形下对所提方法的监控性能进行测试。结果表明,与传统MEW⁃MA和VS-MEWMA控制图相比,所提监控方法对非正态数据具有较强的稳健性,对高维过程具有良好的监控性能。

通过LabVIEW虚拟仪器技术研究随机误差的正态分布

本文以虚拟仪器技术LabVIEW为软件平台,结合NI-USB6009数据采集卡,对直流电压和信号发生器的正弦波信号分别进行测量和数据采集,对直流电压及正弦信号频率和幅值的测量结果进行统计研究,得到电压、正弦信号频率和幅值的统计结果为正态分布.对周期信号增加单个周期的采样数,可以减小频率测量的标准差,提高频率测量的准确度.该实验可以对学生开设为通过实际测量研究随机误差的正态分布规律的实验.