分布参数

Therefore scientists have been engaged in research on approximate solutions of the partial differential equations,e.g.,the difference methods,the methods of characteristic curve and MWR method etc.,i.e., by using approx...

因此不少研究分布参数系统的科学工作者对这方程式近似方法进行了大量的研究，如差分法，特性曲线法和MWR法等；或者把分布参数系统近似成集中参数系统，或者把高价方程简化为低阶方程等。

Finishing calculation of mean value, standard deviation, skewness, kurtosis of Beta distribution.(2) Fitting parameters of many kinds of typical distribution and using residual deviation to evaluate fitting precision.(3) Using Beta distribution as an agreed indication distribution applied to many kinds of practical photoelectric measurement distributions.(4) Deriving theory formula of Bayes point estimation about Beta distribution parameters and mean value and standard deviation on the condition of mean square error loss function and supposed the prior distribution is uniform distribution.(5) Generating MCMC sample from post distribution by the method of Gibbs sample algorithm. Calculating bayes point estimation from sample on the condition of mean square error loss function. Calculating confidence interval by an approximate method to complete interval estimation.

本文的主要工作有：(1)解决了Beta分布参数a和b的精确计算以及均值、标准差、偏度、峰度的计算问题；(2)拟合出10余种典型分布的Beta分布的两个参数，并且采用剩余标准差评价该Beta分布的拟合精度；(3)对多种典型的光学与光电测量系统的测量分布进行了Beta分布统示表示；(4)在假设先验分布为均匀分布前提下，得到参数a和b以及均值μ和标准差σ在均方误差损失函数下的贝叶斯点估计理论计算公式；(5)利用直接抽样的Gibbs抽样算法，从后验分布中产生MCMC样本，从样本直接计算均方误差损失函数下的贝叶斯点估计，并使用一种近似方法计算其置信区间，完成区间估计。

Considering the three parameters Weibull distribution which is more congruous to fact than the two parameters Weibull distribution in dealing with the electric intension data, the method of maximum likelihood estimation and the method of the two binomial regression is applied in estimating the three parameters Weibull distribution in this paper.

鉴于三参数Weibull分布在处理电气强度数据时比二参数更符合实际，本文介绍利用二项式回归法和极大似然法对三参数Weibull分布参数进行点估计的方法。

The thesis can be divided into five parts as follows: First, the structural characteristics of finned-pipe evaporator are analyzed. After selecting suitable microelement controller, the heat-transfer and mass-transfer processes are analyzed for every microelement under the conditions of dryness, wetness and frostiness. Based on previous equations, some parameters of frostiness are confirmed and the frost-growing model is set up under frost condition. Some hypotheses are postulated and with the help of the equation of mass-conservation, energy-conservation and momentum-conservation, the evaporation model which fits in the dynamic simulation is built, which set a solid foundation for system simulation. Second, the starting and stopping behaviors under disturbed condition are analyzed and calculated by using the dynamic concentrative parameter model, which gives some advice to better prescribe refrigeration system and set theoretic foundation for carrying out automatic control of refrigeration system. Third, the normal running process is analyzed and calculated by means of rational matching theory, which gives some advice on how to better understand the parameter change under steady state and the affection of inlet-parameter on evaporator. Fourth, the simulation software with dynamic characteristic is designed, which can be applied to calculate thernio-parameter of cryogen, air humidity and frost thickness under different initial and boundary conditions, and to carry out dynamic simulation under conditions of dryness, wetness and frostiness, at the same time, to achieve detection and simulation at any stage from starting to stopping.

本文的主要内容如下：1对翅片管蒸发器结构特点进行分析，选取适当的微元控制体，就干、湿和霜工况下对每个微元分别进行传热传质分析，基于经验关系式确定霜的有关参数，对于霜工况下的霜生长建立模型，经适当假设，运用质量守恒、能量守恒和动量守恒方程建立适合动态仿真的蒸发器数学模型，为系统仿真奠定基础； 2对蒸发在大扰动下的开、停机过程，运用动态集中参数模型进行分析和计算，为更好地描述制冷系统运行的全过程奠定基础，同时也为制冷系统实现自动控制提供一定的理论基础； 3对蒸发器正常运行过程，运用动态分布参数和参数间定量耦合的观点来分析和计算，为更好地了解稳态工况下各点参数的变化情况及各入口参数对蒸发器动态特性的影响即蒸发器性能对各参数变化的敏感性； 4编写翅片管蒸发器动态特性仿真计算程序，可以计算不同边界条件和初始条件下的制冷剂热力参数、空气温湿度和霜厚度分布场，实现对翅片管蒸发器在干、湿和霜工况下的动态仿真。

Choosing reliability simulation data as a sample, the parameter confidence interval as coding space and the reciprocal of errors between empirical distribution function and acquired distribution function as a fitness function, the point estimation model of age distribution is established based on the genetic algorithm, and the reliability function of complex systems is acquired.

以可靠性仿真数据为寿命样本，待估计参数的置信区间为编码空间，以经验分布与所求分布误差倒数为适应度函数，建立了基于遗传算法的寿命分布参数点估计模型，求得了复杂系统可靠度函数。

The general orthogonal polynomial is adopted for model approximation of DPS and the predictive control of DPS is translated into the lumped one. Model algorithmic control is applied to deal with the lumped parameter system and a control law is given. The predictive controller of DPS is obtained by inverse transformation. The method and steps are discussed in detail.

该方法采用广义正交多项式对分布参数系统的模型进行逼近，将离散时间分布参数系统的预测控制问题转化为集中参数系统的预测控制问题，运用模型算法控制方法对集中参数系统进行预测控制，求出控制律，经反演变换得出分布参数系统的预测控制。

And, a new method for estimating two parameters of Weibull distribution from lognormal distribution parameters is obtained.

在理论上，沟通了两分布间的联系，藉此可利用对数正态分布参数估计威布尔分布参数，从而得到了一种新的两参数威布尔分布的估计方法。

Generalized negative binomial distribution was successfully fitted to all the snail data. The parameters of GNBD from the same bottomlands in different seasons changed differently, and parameters of GNBD from different bottomlands in the same season were not similar even if their snail density were close.

不同季节同一滩地间的广义负二项分布参数的变化不一致，同一季节不同滩地广义负二项分布的参数估计结果即使在钉螺密度相近的情况下也不相近，钉螺生存环境的微小差异可以通过广义负二项分布的参数灵敏反映。

The topographical parameters have been analyzed by taking into account the thermal effect during the friction process. As the results, three kinds of typical topographical features have been observed for the worn surfaces of C G iron with various P content. Namely, C G iron with 0.05% P, 1.30% P, and 0.70% P show worn surfaces characterized by groove ridge, peak pits and their combined topography. The C G iron specimen with peak pits type worn surface topography showes the lowest wear rate and highest friction coefficient, while that with groove ridge type worn surface topography shows the highest wear rate and lowest friction coefficient. The groove ridge type worn surface has a relatively large value of surface height deviation and void volume ratio and negative large value of skewness, which is contrary to the peak pits topography.

结果表明：度销磨损表面主要呈现犁沟型、孤岛型及二者的混合型3种形貌特征，其中具有孤岛型磨损表面形貌特征的试样的摩擦系数较高，磨损率较低；而具有犁沟型磨损表面形貌特征的试样的摩擦系数最低，磨损率最高，分析表面形貌参数发现：犁沟型表面形貌具有最大的表面高度偏差和表面空隙率及高负值的表面高度分布参数；而孤岛型表面形貌的表面高度偏差和表面空隙率最小，表面高度分布参数为高正值。

Distribution laws of divided link and sum link relate exceedingly to the distribution parameters in tolerance analysis and tolerance synthesis. And the numerical value of these parameters influences directly the assemblys reliability.

组成环和封闭环的分布规律与公差分析、公差综合所用到的各分布参数密切相关，分布参数的大小直接影响到装配成功率的高低。

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。