未知

A numerically stable recursive set membership state estimation algorithm for linear discrete-time systems with unknown but bounded noises is proposed, where ellipsoidal sets are adopted to describe the state uncertainties and to bound the process and observation noises.

针对带有未知但有界噪声的线性离散时间系统，提出了一种数值稳定的集员状态估计递推算法。算法采用椭球集合来描述状态的不确定性和噪声的界限。

Be a red-blooded youth, I hope that the oneself can absorb the result of various civilization continuously very, investigate the unknown world continuously, and make a contribution for the development of the society.

作为一名热血青年，我十分希望自己能不断吸取各种文明的成果，不断探求未知的世界，并且为社会的发展作出贡献。

The reflectance of the planet is not yet known.

这颗行星的反射系数仍然未知。

In this paper, we take full advantage of MATLAB statistic tool box to achieve the multivariate nonlinear regression model. Estimate of the unknown parameters. examples are used to validate the method is effective.

文章充分利用MATLAB统计工具箱的优势，通过程序的实现，对多元非线性回归模型的未知参数的估计方法以及对估计后的模型预报做出研究，并以实例验证了该方法的有效性。

This shows that the usual estimator of the regression coeffcient is available when σ2 is unknown.

这表明当方差未知时，回归系数最小二乘估计是一个适合的估计。

The free-surface boundary conditions are satisfied on the free-moving surface exactly without any approximation or linearization. The governing equations and the boundary conditions on the time-dependent, physical domain are transformed onto a regular domain for numerical computations.

为於未知的自由液面边界上满足非线性边界条件，本模式利用座标转换，将非稳态且不规则物理区间的流场控制方程式与边界条件，映射至规则的计算区间，以进行数值解析。

A method of adaptive observer design for two-dimensional systems with relative degree two was presented.

现对相对阶为二的二维系统提出了一种观测器的设计方法，允许和未知参数相关的项与所有状态有关；同时对高维情况也作了初步考虑，并举例说明了本方法的有用性。

Whether or not he succeeded in repelling the Yuuzhan Vong threat is unknown.

而他是否成功的抗击了遇战疯的进攻则尚属未知。

The algorithm must exploit the trait of environmental model, replan motion according to the change of environment.

文中的主要研究工作和贡献如下：（1）未知环境的覆盖规划中，采用改进的滑动算法，并结合环航和随机行走等策略，使得多机器人队伍能够一边探索障碍物信息，一边增量的构建构型空间。

The stability problem leads to an ordinary differen-tial equation containing three parameters representing partialderivatives of a phase function.

一个非定常流动的稳定性问题被归结为求解三个未知函数为参数的微分方程的特征值，其三个参数分别是非线性扰动波的相函数的导数及圆盘运动速度的函数。

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％。