随机

When the random error is not subject to normal distribution, the least absolute deviation estimation is superior to the least squares estimation. In addition, the robustness of the least absolute deviation estimation is also better than that of the least squares estimation.

在随机误差不服从正态分布的问题中，最小一乘估计的统计性能优于最小二乘枯计；另外，最小一乘估计的稳健性更强。

Then the digital audio signal is set into segments and DWT is performed. Finally the modulated signal is embedded in the coefficients with relatively large absolute value on middle frequency range detail signal adaptively. The original digital audio signal is necessary when detecting the watermark.

在应用扩频技术的算法中，首先将视觉上可辨的二值水印图像降维为一维序列，再将一维水印序列伪随机排序并与m序列作扩频调制，最后对数字音频信号进行分段离散小波变换，把经过调制的水印信息自适应地嵌入到原音频信号小波分解中等尺度绝对值较大的分量上。

First, we discuss several theories of risk measures respectively such as theories ofcoherent measures of risk, spectral measures of risk and distortion measures of risk.Within the framework of these theories, we discuss and compare standard deviation,mean absolute deviation, lower partial moment, Ginis difference, VaR, CVaR and soon. We conclude that CVaR is superior to other measures with respect to theoreticalproperties.

首先，本文分别讨论了一致风险测度理论、谱风险测度理论、失真风险测度理论和随机占优一致风险测度理论等风险度量评价理论，在这些理论框架内讨论和比较了标准差、平均绝对离差、下偏位矩、基尼均差、VaR以及CVaR等风险度量。

Suppose Y is an absolutely continuous random variable symmetric about 0 with probability density function f and cumulative distribution function F.

假设Y是一绝对连续且对称於0的随机变数，其机率密度函数为f，而分布函数为F。

Methods Two hundred and ninety seven middle-aged and aged females were sampled randomly from the cases who were examined in the bone mineral density measurement department of The Second Affiliated Hospital of Nanchang University from January 2004 to January 2006, and their age, stature and body weight were recorded exactly. The BMD of lumbar (L2~4), femoral neck, Ward's and great trochanter was measured by dual energy X-ray absorptiometer, then statistically analyzed.

从2004年1月～2006年1月在南昌大学第二附属医院骨密度测定室检测的就诊者中随机抽取297例中老年妇女，准确记录其年龄、身高、体重；采用法国DMS公司Challenge：双能X线骨密度测定仪检测腰椎(L2~4)、股骨颈、ward's三角以及大转子的BMD，然后进行比较和统计分析。

ABSTRACT This dissertation proposes a number of extended theories of stochastic Petri net and other algorithms to evaluate the performance of various computer networks.

本文提出了一系列随机Petri网的扩展理论和逐次迭代逼近算法，从理论分析角度深入分析了各种计算机网络的多项性能指标。

The influence of the stiffness of the gravity abutment on the stress of the arch dam is also analyzed.

接着分析了抗剪强度参数的选择及渗透压力对可靠指标的影响，并讨论了随机变量的分布类型、截尾情况以及相关关系对可靠指标的影响。

At first, the basic theory and general process of the gravity abutment corresponding with definite solution are simply introduced.

然后在随机有限元的基础上进行拱坝的拱座——重力墩的强度和抗滑稳定可靠度分析，计算相应的可靠指标。

Although stocks' returns are the main concerns for almost all of the academical researches about stock market, returns' random processes are even more important for correct investment decision making, because they provide the basic information about capital ri

在几乎所有的关于市场的学术研究中都会涉及到股票的收益率，而在股票市场，对收益率随机过程的充分认识是作出正确投资决定的基础，因为它提供了有关资产风险的基本信息。

To make an epidemic survey and species of intestinal acariasis in part areas of Anhui Province, case history, stool examination (saturated saline flotation method), and blood examination were taken for 3416 persons.

某些粉螨可侵入并寄生在人体泌尿系统引起尿螨病。为探讨尿螨病的流行病学特征、主要临床表现和发病机理，我们用ELISA方法对随机选取的1994例人群进行血清总IgE筛查，用1∶1000浓度粉螨变应原浸出液于前臂皮肤进行皮肤挑刺法检查。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。