查询词典 necessary and sufficient conditions

At the same time, for the process additive and multiplicative uncertainties mostly encountered in practice, the sufficient and necessary conditions for holding the control system robust stability are analyzed, and thus, an intuitive determination method is provided based on the spectral radius criterion.

同时，对于实际中最常见的被控过程的加性和乘性不确定性，分析了控制系统保证鲁棒稳定性的充要条件，由此给出了基于谱半径判据的直观判定方法。

At the same time, sufficient and necessary conditions for holding the control system robust stability are analyzed in the presence of the process additive and multiplicative uncertainties often encountered in practice, and correspondingly, the on-line rule for tuning the adjustable parameters of the decoupling controller matrix is provided.

同时，对于实际中常见的被控过程的加性和乘性不确定性，分析了控制系统保证鲁棒稳定性的充要条件，从而给出在线整定解耦控制器矩阵的可调参数的规则。

Li and one of his lemmas toabbreviate the nonnormal Cayley digraph 〓 into the case when 〓 is a dicycle.When 〓 is a dicycle,we give the sufficient and necessary conditions for 〓 to benonnormal and the structure of the corresponding automorphism group Aut.

Li定义的一个图〓，其中N是Aut的一个非平凡极小正规子群，和他的一个引理，把对非正规Cayley有向图Γ的讨论简化到〓是一个有向圈的情况，进而决定了当〓为有向圈时，Γ非正规的充要条件和Aut的结构。

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。

By using of the comparison theorem and some results, some sufficient and necessary conditions are derived for permanence of the periodic system and non-permanence of predators.

运用比较定理和一些主要结果，得到了系统永久持续生存和捕食者灭绝的充分必要条件。

This article uses the implicit function theorem and the properties of analytic functions,with less limitations for the uniqueness,continuity,continuous differentiability of the implicit functions,and gets the sufficient and necessary conditions of the existence of implicit functions by simplifying them.

从常用隐函数存在性定理出发，放宽对隐函数唯一、连续、连续可微等性质的限制，利用解析函数的性质将其展拓，得到广义隐函数存在的充分必要条件和广义隐函数的分布特征。

Convergence, convergence in probability, and convergence in distribution. And some sufficient and/or necessary conditions are also given.

收敛、统计依概率收敛的充要条件或充分条件，此外还讨论了几种收敛性之间的一些关系。

In the second part, we studied blind source separation in ill conditioned cases, obtained the sufficient and necessary conditions on solvability, and presented the neural network model and corresponding adaptive algorithm. We also discussed the blind digital source separation, established the blind separation and extration models and algorithms. These algorithms can be used to deal with high noise and ill-conditioned cases.

在第二部分，我们研究了奇异混合情形下信号盲分离问题，给出了神经网络模型及相应的自适应算法；我们也研究了数字信号盲分离问题，得到了有关可解性的充要条件，提出了分别处理低噪声问题和高噪声问题的算法，这些算法对感知信号个数少于源信号个数等病态问题也适用。

Firstly, the recent developments in controllability and observability for switched system are reviewed. Secondly, by means of properties of invariant subspace, the controllability for switched systems with continuous-time and discrete-time subsystems, and a class of discrete impulsive switched systems is respectively investigated. Some sufficient and necessary conditions of controllability are proved. In the end, some simple criterions for controllability and observability of switched symmetric composite systems are set up.

首先介绍了切换系统能控性与能观性方面的一些重要结论；其次，用不变子空间的性质分别研究了同时含有连续子系统和离散子系统的切换系统和一类离散脉冲切换系统的能控性，建立了相应的充分性与必要性判别准则；最后，研究了切换对称组合系统的能控性与能观性，得到了此系统能控性与能观性的简单判据。

And the sufficient and necessary conditions of the monotone set function which is continuous of the empty set and the full set are given.

李军[6]引入了强序连续性概念，证明了单调测度空间上实值函数的Lebesgue定理成立的充要条件是单调集函数具有强序连续性。

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％。