共查询到20条相似文献，搜索用时 109 毫秒
1.
赵伟 《中学生数理化(高中版)》2013,(2):6-6
现具体介绍有关离散型随机变量的结论,并通过一些典型例题说明解这类题的常规方法。设X是离散型随机变量,若Y=ax＋6,其中“、b为常数,则y也是随机变量,且P（Y=axi＋b）一P（X=xi）（i可取1,2,…,n）,EY=E（aX＋b）=aEX＋b。 相似文献
2.
陈瑾 《赤峰学院学报(自然科学版)》2009,25(4):1-2
本文讨论了当X1,X2…,Xn（-∞,∞）上分布函数分别为F1,F2,…,Fn的n个随机变量,其中Fk∈S（r）,k=1,2…n,{θk,1≤k≤n}是与{Xk,1≤k≤n}独立的n个相互独立随机变量情形下,重尾随机变量的随机加权和,证明了当→∞时渐近关系式p（^n∑i=1θiXi〉x）-∑i≠jFi（γ）^-Fi（x/θi）成立 相似文献
3.
谭智平 《衡阳师范学院学报》1999,(3)
若X1,…,Xn为独立随机变量,X1…Xriid．~F（x）,Xr＋1,…,Xniid．~G（x）,其中F（x）,C（x）皆为连续分布函数,F已知,G未知。r／n（t0）为序列的变点。借用Cusum和BrownianSheet,我们提出了一种检验变点t0的非参数程序。 相似文献
4.
有关两两NQD随机变量序列的协方差不等式 总被引：2，自引：0，他引：2
孙桂萍 《常熟理工学院学报》2008,22(10):31-32
设{Xn,n≥1}为两两NQD（Negatively Quadrant Dependent）随机变量序列的,对于NA随机变量X和Y有协方差不等式｜cov（f（X）,g（Y））｜≤sup｜f′（x）[sup｜g′（y）｜[-cov（X,Y）],本文通过对两两NQD随机变量性质的研究证明了对于两两NQD随机变量X和Y有同样的协方差不等式成立． 相似文献
5.
张计珍 《雁北师范学院学报》2000,(3)
定理设于样（ζ1,ζ2…,ζ3）是来自正态母体N（Oδ2）,。约的随机向量,是正交矩阵,独立且同服从（O,）分布．证明：因为（1,乙,…,已独立且同服从N（O,。’）分布,所以n维随机向量（乙,h,…,乙）的联合分布密度函数为：而变换的雅可比行列式的绝对值为D入一1,所以,（刁;,v。,…,＊）的联合分布密度函数为其中,－ac＜y,r。,”””入;＜””‘所以,小,9。,…,W独立且同N（O,。‘）分布．例1已知己口独立且卜NI,3）,7－NZ,2－h＿,t,t。、。。＿＾＿＿＿＿t：xe,求（X,川的联合密度函数．解：由已知… 相似文献
6.
一个三角形当其周长为定值时,它的面积最大者为正三角形．这一命题的证法很多,本文绘出一个用矩阵证明的方法．设三角形的周长为L,三边长分别为X,y,Z,其面积为X,y,Z的函数,记为S（X,y,X）,这里X＞0,y＞0,Z＞0且X＋y＋Z＝L．－．面用等周的线性变换设最初三角形三边长为X。,yo,Z。,作下列线性变换由平面几何常识知,有S（x。,Y。,z）＜s（x;,y;,z）＜s（x。,y。,z）＜s（x。,y。,z）且Xi＋yi＋Zi—L（i＝0,1,2,3）故上述线性变换保持三角形周长不变且使三角形面积增加,称其为面增等周线性变换．合并… 相似文献
7.
众所周知,连续型随机变量的严格数学定义是:设X是随机变量,F(x)是其分布函数,若存在非负函数f(x),使对任意实数x,都有 F(x)=integral from n=-∞ to x f(y)dy则称X是连续型随机变量(见[1])。但是,近年来出版的几种概率论方面的教材都有意或无意地将连续型随机变量和“连续 相似文献
8.
张昌斌 《郧阳师范高等专科学校学报》1994,(2)
5、广义拟变分不等式 定理5.1 设E,F都是Hausdorff拓扑线性空间,F局部凸（F~o分离F的点）,XE是非空仿紧闭凸集,YF非空凸,S:X→2_Y上h一半连续且具非空闭（紧）凸值,T:Y→X是可逆的,保凸的和开的,P:Y→2~（F~o）单调具非空值且对任一一维线段∠F,P│∠∩Y由F的拓扑到F~o的弱~o拓扑下半连续,再设 （i）△_o={x∈X:sup sup Re（u,T~（-1）x-y）>0）}是X的相对开集, y∈S（x） u∈P(y) （ii）存在y_o∈Y及E的非空紧子集KX使得 inf Re（w,T~（-1）x-y_o）>0,y_o∈S（x）,x∈X/K w∈P（T~（-1）x） 则存在∈X使得T~（-1）∈S且 sup Re（u,T~（-1）-y（≤0,y∈S（5.1） u∈P（T~（-1）） 证令φΨ:XxY→R, φ（x,y）=sup Re（u,T~（-1）x-y）,Ψ（x,y）=inf Re（w,T~（-1）x 相似文献
9.
本文讨论了独立随机变量之和的绝对中心矩的几个性质,其中包括E｜（X＋Y）-E（X＋Y）｜-E｜（X-Y）-E（X-Y）｜的表达式,这里X和Y是相对独立的随机变量. 相似文献
10.
刘晓华 《成都教育学院学报》2002,16(6):30-30,68
文章研究一维连续型随机变量X的函烽Y＝|X|和Y＝X^2的分布以及二维连续型随机变量（X，Y）的函数Z＝kX＋bY的分布，从而得到Y=|X|,Y=X^2及Z＝kX bY的密度函数的计算公式。 相似文献
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12.
采用平滑线散点图分析某高校招生部门提供的2005～2009年分省、直辖市所录取新生入学报到率历史数据,应用基于时间序列法的新生入学报到率预测模型预测了2010年14个省、直辖市新生入学报到率,与实际报到率相比较结果显示由模型预测出的2010年新生报到率绝大部分处于置信区间．该模型可为高校招生部门在各省、直辖市投放招生指标提供一种定量决策方法． 相似文献
13.
由于CCD本身的散粒噪声以及外界环境的影响，采集到的信号往往有一定程度的失真和变形，存在许多“毛刺”，不利于数据的计算和分析。本文采用3次B样条小波对原始信号进行分解，对分解后的数据进行平滑处理，最后重构得到平滑信号。本文最后给出了对比试验结果以证明方法的有效性。 相似文献
14.
Current curve smoothing technologies provide a smoothed curve by joining together separate curves that have certain degrees of continuity at junctions. These technologies have found many applications in science and engineering. However, none of them can provide a smoothed curve using a single continuous function for arbitrary segmental curves. This paper reports a new approach that can be used to construct a single continuous function that joins an arbitrary number of different segmental curves, with the required degree of continuity at all junctions. The smoothness of transition at different junctions can be controlled by separate parameters to suit different needs. The combined continuous function can approach the original segmental functions asymptotically or match the original segmental functions “exactly” inside each segment by adjusting the smoothness parameter. This new approach may also find application outside the scope of curve smoothing/curving fitting in the future. 相似文献
15.
雷桂媛 《浙江大学学报(A卷英文版)》2002,3(3):339-343
The rejection sampling method is one of the most popular methods used in Monte Carlo methods. It turns out that the standard rejection method is closely related to the problem of quasi-Monte Carlo integration of characteristic functions, whose accuracy may be lost due to the discontinuity of the characteristic functions. We proposed a B-splines smoothed rejection sampling method, which smoothed the characteristic function by B-splines smoothing technique without changing the integral quantity. Numerical experiments showed that the convergence rate of nearly O(N-1) is regained by using the B-splines smoothed rejection method in importance sampling. 相似文献
16.
近红外光谱法快速测定六味地黄丸中水分含量 总被引：1，自引：0，他引：1
采集不同厂家不同批号六味地黄丸样品的近红外光谱图,将其经First Derivative+MSC预处理,采用Savitzky-Golay平滑法(5点3阶数据平滑)处理,以滤去噪声,在7 819~4 038 cm-1谱段范围内,选择前10个主因子数,利用偏最小二乘法建立六味地黄丸的近红外光谱与药典参考方法测得的水分含量之间的相关模型。建立的水分定量校正模型相关系数R2=0.990 4,内部交叉验证均方差(RMSECV)=0.250 2,预测均方差(RMSEP)=0.099 7,平均回收率为100.75%。本实验所建模型性能较好,对六味地黄丸中水分含量有很好的预测能力,可实现大批量样品的快速检测,对中药制剂的质量分析有一定的参考价值。 相似文献
17.
Neil J. Dorans 《Journal of Educational Measurement》2002,39(1):59-84
The process employed to produce the conversions that take scores from the original SAT scales to recentered scales, in which reference group scores are centered near the midpoint of the score-reporting range, is laid out. For the purposes of this article, SAT Verbal and SAT Mathematical scores were placed on recentered scales, which have reporting ranges of 920 to 980, means of 950, and standard deviations of 11. (The 920-to-980 scale is used in this article to highlight the distinction between it and the old 200-to-800 scale. In actuality, recentered scores were reported on a 200-to-800 scale.) Recentering was accomplished via a linear transformation of normally distributed scores that were obtained from a continuized, smoothed frequency distribution of original SAT scores that were originally on augmented two-digit scales (i.e., discrete scores rounded to either 0 or 5 in the third decimal place). These discrete scores were obtained for all students in the 1990 Reference Group using 35 different editions of the SAT spanning October 1988 to June 1990. The performance of this 1990 Reference Group on the original and recentered scales is described. The effects of recentering on scores of individuals and the 1990 Reference Group are also examined. Finally, recentering did not occur solely on the basis of its technical merit. Issues associated with converting recentering from a possibility into a reality are discussed. 相似文献
18.
针对雾霾天气下有雾图像能见度水平低、在低光照条件下无法有效获得图像细节信息等问题,提出一种基于暗通道先验的Retinex去雾算法.首先采用改进的暗通道先验算法对有雾图像进行初步处理,得到初步复原图像;其次,在得到的去雾图像上进行Retinex图像增强,利用引导滤波对照度分量进行平滑处理,求出反射分量;之后利用S型曲线对... 相似文献
19.
Since the jets and detonation gaseous products are separated by sharp interfaces, the traditional smoothed particle hydrodynamics (SPH) method is difficult to avoid the computational instability at interfaces. The multi-phase SPH (MSPH) method was applied to improving the stabil-ity, which smoothes the particle density and makes pressure continuous at interfaces. Numericalexamples of jet forming process were used to test capability of the MSPH method. The results show that the method remains algorithm stability for large density gradient between the jets and gaseous products and has potential application to both the explosion and the jet problems. The effect of initiation ways of the shaped charge was discussed as well. 相似文献
20.
Since the jets and detonation gaseous products are separated by sharp interfaces,the traditional smoothed particle hydrodynamics (SPH) method is difficult to avoid the computational instability at interfaces.The multi-phase SPH (MSPH) method was applied to improving the stability,which smoothes the particle density and makes pressure continuous at interfaces.Numerical examples of jet forming process were used to test capability of the MSPH method.The results show that the method remains algorithm stability for large density gradient between the jets and gaseous products and has potential application to both the explosion and the jet problems.The effect of initiation ways of the shaped charge was discussed as well. 相似文献