方差比

Because the actual cost is less than standard cost, the variance is favorable.

因为实际成本比标准成本更少，方差是有利的。

Experiments on LVCSR test showed that the method can achieve nearly 20% relative error reductions compared to the traditional diagonal gaussian modeling method and cause less computation cost during decoding.

在汉语普通话连续语音测试和广播语音的连续语音测试中，本文提出的相关性特征建模方法在增加较少的内存占用量和解码计算量的情况下，能够比采用传统的具有对角方差结构的高斯混合模型的建模方法获得20％的相对误识率的降低。

The relationships of bias and mean square error of EFT with SNR and forgetting coefficient are studied.

该文对EFT的瞬时频率表示偏差、均方差值的统计特性与信噪比及遗忘系数的关系进行了分析，给出了相应的仿真结果。

By comparison of the standard variance of predictive error, we can find that fuzzy T-S model is more precise than conventional ARX model.

从预测误差方差的分析对比结果来看，该模型预测比传统的ARX线性模型预测要准确。

The main results are as follows:We review the existing Monte Carlo control variates estimators of the price of Asian options and propose a new one. According to pratical needs, we define efficiency as the inverse of the product of the variance of an estimator and its computational time and make it a standard for comparisons to draw the following conclusions: Firstly, the more control variates correlate with arithmetic average Asian options, the larger is the efficiency of an estimator with these control variates, but among which the geometric average option plays the most important role; Secondly, an estimator with more control variates is better than one with less ones only when the time to maturity is long and the volatility is high.

在综合已有研究工作的基础上，本论文的主要创新成果如下：（1）我们回顾了已有的亚洲期权价格的蒙特卡罗控制变量估计，并提出了一个新的控制变量估计，且从客观实际出发，将估计值的方差和计算时间的乘积的倒数定义为效率并以它为标准比较各估计，得到以下结论：与算术平均亚洲期权相关程度越大的控制变量构成的估计的效率越大，而其中起主要作用的控制变量为几何平均亚洲期权的价格；只有在到期时间较长且标的资产的波动率较大时，元素多的多元控制变量估计比元素少的效率大。

ANOVA,regression method and likelihood ratio test can be applied in single-marker mapping.

单一标记分析法可以采用方差分析、回归分析或似然比检验的方法分析。

Experiments are made to compare the improved method with the traditional maximum classification square error method and the simple genetic algorithm.

通过实验对比，表明改进的遗传算法比传统的最大类别方差法和基本遗传算法有明显的优势，说明了本算法的可行性。

And such methods V/m ratio t-test, negative binomial parameter, index of dispersion, Cassie index, index of clumping, index of mean crowing and index of patchiness are employed to analyse various dominant populations of Heptacodium miconioides community in the Tiantai Mountain in Zhejiang province and distributive patterns of Heptacodium miconioides community in different quadrats, and this paper also examines the intensity of Heptacodium miconioides population in different quadrats by means of stand classes.

摘 要 以浙江省天台山七子花群落为研究对象，采用相邻格子样方法取样数据，应用方差／均值比的t检验法、负二项参数、扩散型指数、Cassie指标、丛生指标、平均拥挤指数和聚块性指数等方法，分析了七子花群落各优势种群以及七子花种群在各样地中的分布格局，并分立木级对七子花种群在不同样地内的集群强度进行了测定。

Evaluation of the approach is implemented using a simulated piecewise smooth signal.

结果显示特别是在信号采样序列的长度有限时，采用本文方法可以获得比中值估计方法更准确、更可靠的白噪声方差估计。

Analytical variance of the estimation declines linearly by increasing the bit signal-to-noise ratio for the proposed channel estimator.

理论分析结果表明，该算法的对数估计方差随比特信噪比的增加而线性减小。

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务，乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐，因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。