查询词典 necessary condition

Moreover, by augmenting state vectors, the sufficient and necessary condition of mean square stability is obtained.

此外，通过增广状态向量利用系统的Markov切换特性得到了系统均方稳定的充分必要条件。

The paper addresses the existence problem of generalized inverses for elements of a Banach algebra under perturbations and derives a sufficient and necessary condition for the existence of generalized inverse.

文中讨论了Banach代数元扰动后广义逆的存在性问题。用线性算子广义逆的稳定性问题的方法，得到Banach代数元扰动后广义逆存在的充分必要条件以及稳定的一个充分条件

Based on the above results, plane strain deformation is considered to be a necessary condition of shear banding.

基于对以上研究结果的讨论，本文认为，剪切带是在平面应变变形条件下当应变硬化率降到很低时发生的。

And then some ellipses that AUGR estimator is better than the OLS estimator and AUGL estimator is better than the OLS estimator are given, respectively.Second, the definition of the almost unbiased unified biased estimator is proposed. This definition includes the familiar almost unbiased estimators in literatures, and it is the unified expression of the familiar almost unbiased estimators. Followed the biased and variance are compared of AUUB estimator and the unified biased estimator, respectively. AUUB estimator has smaller bias than UB estimator and the variance of AUUB estimator is between the variance of UB estimator and 4 times of the variance of UB estimator. Finally the properties of AUUB estimator are discussed. The conclusion is gained that there are parameters made AUUB estimator is better than OLS estimator in terms of their mean square error. The sufficient and necessary condition that AUUB estimator is admissible is given. The ellipse is given that AUUB estimator is

然后给出了几乎无偏统一有偏估计的定义，该定义包括了文献中常见的几乎无偏估计，实现了常见几乎无偏估计的统一表达式；接下来我们比较了几乎无偏统一有偏估计与统一有偏估计的偏度与方差，得出了几乎无偏统一有偏估计比统一有偏估计有较小的偏度，几乎无偏统一有偏估计的方差介于统一有偏估计的方差与统一有偏估计的方差的四倍之间的结论；最后我们对统一有偏估计的主要性质作了讨论，证明了存在参数K，S使得几乎无偏统一有偏估计在均方误差意义下优于最小二乘估计的结论，给出了几乎无偏统一有偏估计为可容许估计的充要条件，还给出了在均方误差阵意义下几乎无偏统一有偏估计优于最小二乘估计的椭球。

Applyingthe sufficient and necessary condition of biquadratic Bézier patch being non-negative,a method is presented to see whether two points are the closest points between twobiquadratic NURBS surfaces when the two points are respectively on the two surfaces. Based on the method, the surface split algorithm is improved while the surfaces arebiquadratic NURBS surfaces.

本文利用双二次 Bézier 曲面为非负的充要条件，提出了分别位于两张双二次 NURBS 曲面上的点是否为这两张曲面间距离最近的点的判别方法，并由此在双二次 NURBS 曲面的场合对计算最短距离的曲面分割法作了改进。

Based on the invariance of maximum likelihood estimation, the sufficient and necessary condition under which the maximum likelihood estimation has invariance for the parameters are given, then it uses this conclusion to calculate the maximum likelihood estimation of σ^2 and ρ for bivariate normal distribution.

根据参数极大似然估计不变性原则，给出在一定条件下极大似然估计具有不变性的充分必要条件，并利用该结论计算了二元正态分布Z=的未知参数σ^2和ρ的极大似然估计值。

Secondly, for the boundary correspondence of affine stretch on hyperbolic regions, we prove that the above conclusion is also true. Finally, we pose a sufficient and necessary condition for the same conclusion.

最后利用退化的四边形序列，给出了拟对称同胚的极值拟共形延拓的最大伸缩商、四边形模之比的上确界及拟对称同胚的边界伸缩商三者相等的一个充要条件。

From [1], Every transition function is a positive strongly continuous semigroup of contractions on l\, but it isnt a strongly continuous semigroup on l_∞- In fact, the sufficient and necessary condition for a transition function to be a strongly continuous semigroup on l_∞ is that the q—matrix Q is an uniformly bounded q—matrix on l_∞- This is the trivial case.

由Anderson[1]知道转移函数P是l_1空间上正的强连续压缩半群，但P一般来说不是l_∞空间上的强连续半群，而P是l_∞上强连续半群的充要条件是q—矩阵Q是l_∞。

We first show some properties of such operators and give an explit description about the image of a linear bounded operator on a linear normed space. Then based on these results, we show the mean ergordic theorem on a C*-bial-gebra and get a sufficient and necessary condition for a linear functional to be Haar measure. Finally we discuss the sufficent conditions for the existence of Haar measure on C*-bialgebras.

本文首先通过考察这样算子的性质和刻画赋范线性空间中连续线性算子的像集的性质，证明了C*－双代数中的一个平均遮历定理，得到了C*－双代数中的线性泛函是 Haar 测度的充分必要条件；利用遍历定理和这个充分必要条件探讨了C*－双代数中 Haar 浏度存在的一些充分条件。

From the theory aspect, human capital is the main body and headspring of technology innovation as well as the necessary condition for technology diffusion; thus the quantity, configuration, disposition of human capital which one country or area owned will affect its innovation abilities.

从实证分析看，我们选用了我国的R＆D投入产出数据进行了分析，得出了人力资本是影响(来源：ABC论66文网www.abclunwen.com)技术创新的重要因素，增加人力资本投入可以提高技术创新能力。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。