参数变量

The algorithm is derived by proper transformations based on gamma distribution random variables.The algorithm is computationally simple.

该算法计算简单，通过调整分布参数的值，可产生具有任何形状参数和任何方差的广义高斯分布随机变量。

The following conclusions have been made in this paper.(1) Based on CO_2 flux data of eddy covariance, variation characteristics of gross primary productivity in four flux observation stations were studied, which are an alpine meadow, an alpine shrub meadow, a swamp alpine meadow and a steppe alpine meadow at Dongxiong. The results show that photosynthetic capacity of the alpine meadow is the highest, and the annual total GPP is 652.2g C/m~2. Daily-differencing approach is used to analyze the random error of CO_2 fluxes measurements. The results show that the distribution of random error follows more closely follows a double-exponential, rather than a normal distribution, capturing the high peak and thick tail, and the random error varies with environment variables, which violates the assumptions for the ordinary least squares fitting with normality and homoscedasticity, consequently, we introduce maximum likelihood method for parameter optimization.

本文主要在以下几个方面开展工作并获得了一些认知和结论：(1)通过分析样带区域内高寒草甸、高寒灌丛、沼泽化湿地和草原化高寒草甸四个通量观测站点草地生态系统总初级生产力变化特征，研究结果表明HBBT矮嵩草草甸生态系统植被光合作用能力较强，年GPP总量为652.2 gC/m~2，明显高于其他三种生态系统；通过利用"单塔日变化法"获得四站点通量观测数据随机误差，结果表明通量观测随机误差概率分布呈现尖峰厚尾的特征，与正态分布相比，更服从双边指数分布，进一步分析表明通量观测随机误差随环境变量(风速、温度和光合有效辐射)的变化而变化，这违背了普通最小二乘法进行生态过程模型参数优化正态分布且误差同质的假设，因此本研究中引入最大似然法进行生态过程模型参数优化。

In nonparametric statistical theory, the nonparametric regression model that is with the given sample of observations are independent and identically distributed and the response .

在非参数统计理论中，对于给定的一组关于两变量和的非参数回归模型，其中已知，希望通过对的核估计得到更好的拟合模型。

Rice ; biophysical parameter ; leaf area index ; spectral variable ; biomass ; water content ; leaf shape parameter

水稻；生物物理参数；叶面积指数；光谱变量；生物量；含水率；叶形状参数

The three characteristic parameters as input,we obtain the apple grade based on fuzzy al

要由苹果的大小、形状和成熟度决定；该分拣系统有三个输入参数即大小、形状和成熟度，其三个特征参数的提取应用了数字图像处理技术；一个输出变量即苹果等级分类，分别标为A、B、C三类。

According to Floquet theory and transition curves of Mathieu equation, two different modified strained parameter methods are compared on precision of periodic solutions.

中文摘要：为研究参数横摇对船舶运动和倾覆的影响，通过对船在规则波上随浪航行时，恢复力矩中出现的1个以正余弦规律变化的强参数激励项进行适当的变量置换，将船舶的横摇运动方程转换成标准形式的Mathieu方程。

In order to study the effects of parametrical rolling on the ship movement and tilts, in allusion to ship's navigating in regular following waves, the equation of ship rolling motion is transformed into normal Mathieu equation by proper variable replacement when strong parametrical excitation in restoring moment varied according to sine or cosine wave.

为研究参数横摇对船舶运动和倾覆的影响，通过对船在规则波上随浪航行时，恢复力矩中出现的1个以正余弦规律变化的强参数激励项进行适当的变量置换，将船舶的横摇运动方程转换成标准形式的Mathieu方程。

Considering the randomness of the structural physical parameters and utilizing the random variable's functional moment method and the algebra synthesis method, the mean value and the variance of the mean square value of the structural displacement response under stationary random excitation are computed firstly from the expressions of structural stationary response in frequency domain. And then the expressions of the mean value and the variance of stochastic rigid frames dynamic reliability are educed from the Poisson formula of calculating dynamic reliability.

考虑结构的物理参数具有随机性，从结构随机响应的频域表达式出发，利用求解随机变量数字特征的代数综合法和矩法，导出随机参数刚架结构在平稳随机激励下的位移及速度响应均方值的数字特征，再由动力可靠性的Poisson公式导出结构动力可靠度的计算公式。

By use of the referential variables and perturbational variables the medium parameters of wave equation were rewritten.

利用参考场量和扰动变量对声波方程中的介质参数进行处理，并利用Green函数理论得到扰动参数比的积分方程。

The equation to calculate natural frequency and the expression of dynamic response have been built, and the digit characteristics of natural frequency random variable and dynamic response are derived.

推导出了求解随机参数链式结构动力特性的方程式和随机参数链式结构动力响应的计算表达式，并推导了结构固有频率和动力响应随机变量的数字特征计算表达式。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。