查询词典 optimal

It provides a way to find optimal lower dimensional approximations of the given data, and It enormously reduce the storage of the data which is needed when the physical processes is recurred. The physical process can be described in series expansion function that only is related to the time and space. It is optimal approximation of the given data in a certain least squares optimal sense. The most obvious advantage of the method is that it reduces the computation cost and computation time markedly.

它提供了一种描绘物理过程的有效方法，该物理过程可以写成一个只与时间相关的函数和一个只与空间相关的函数的展开式序列，且它们在均方意义上是最优的，在展开式中只需要少量的项数就可较准确地描述该物理过程，因此降低计算维数、减少计算量和节省计算时间是这个方法最明显的优点。

In the paper, many further discussions about the optimal control problem,the approximate optimal solution to generalized time optimal control problem and stability of the degenerate systems with delay are considered and some important and meaningful results are obtained in it.

而本篇论文则是对具有时滞的退化系统的最优控制问题，广义时间最优控制问题的近似最优解和稳定性问题进行了讨论并且得出了一系列的重要成果。

First low order approximation of generating function and approximate optimal trajectory were obtained. Then using low order approximation of generating function of Hamilton "relative motion" to the approximate optimal trajectory, improvement of the approximate optimal trajectory was iteratively made. In this way, high order approximation accuracy can be obtained by only using low order approximation, which is much cost effective in computing.

首先以较低的计算代价，获得最优控制Hamilton系统生成函数的低阶近似，得到一条近似的最优轨线，然后将最优控制Hamilton系统相对于近似最优轨线求"相对运动"，该"相对运动"仍具有Hamilton性质，利用这一"相对运动"的生成函数低阶近似，可以对近似最优轨线进行迭代修正，从而以计算代价较小的低阶近似逼近计算代价高得多的高阶近似的精度。

In our thesis, contents are organized as following In Chapter 1 we present our topic's internal and overseas research situations, theoretical and practical significance, and introduce the research object and contents, and the main contributions of this dissertation. Chapter 2 reviews the development of the stability results for nonlinear systems and some relevant recent results, which include Lyapunov and LaSalle-Yoshizawa theorems for nonlinear systems, and stochastic edition for stochastic nonlinear systems. Sontag's formula for systems affine in control is presented in the frame of CLF. The concepts of disturbance attenuation and the inverse optimality are also explained in this Chapter. In chapter 3 we present the solvable theorem of inverse optimal gain assignment problem, design the inverse optimal controller and the inverse optimal tracking controller for strict-feedback nonlinear continuous systems with unknown time-varing bounded disturbances and constant unknown parameters using an adaptive backstepping algorithm, which are nonlinear, continuous and are easier to realize. These designs are fully systematic and the algorithm can be directly coded in symbolic software. The results of simulation show the effectiveness of the control algorithms.

论文的结构如下：在第1章中，给出了本文研究课题的研究现状、理论意义和实际应用，并介绍了本文的研究对象、研究内容以及主要贡献；在第2章中，针对确定性非线性系统和随机非线性系统，分别介绍了Lyapunov定理、LaSalle-Yoshizawa定理及其随机版本；对仿射系统，在控制Lyapunov函数框架下，给出了Sontag公式；同时给出了非线性系统扰动抑制和逆最优控制问题的基本概念；在第3章中，针对具有未知时变有界扰动和未知定常参数的一类不确定非线性系统，给出并证明了逆最优增益配置可解定理，使用自适应Backstepping算法和均值定理，系统地设计了自适应逆最优控制器和逆最优跟踪器，这种设计方法可同时获得逆最优控制策略和自适应律，简单明了，仿真结果表明该控制算法的有效性，并给出了性能估计。

In Chapter 4 we discuss the solvable theorem of adaptive inverse optimal control problems, and proceed with controller designs of global asymptotic stability in probability, adaptive inverse optimal stabilization in probability and output-feedback adaptive inverse optimal stabilization in probability for strict-feedback stochastic nonlinear continuous systems with additive standard Wiener noises and constant unknown parameters using It〓's differentiation rule and an adaptive backstepping algorithm. Control laws and adaptive laws can be obtained at one time by this design scheme. Many simulations have been performed to validate the properties of the proposed adaptive control scheme.

在第4章中，针对具有标准Wiener噪声扰动和未知定常参数的不确定随机非线性系统，提出并证明了自适应逆最优控制问题可解定理，构造了适当形式的四次型随机控制Lvapunov函数，基于It〓微分规则和自适应Backstepping算法，系统地设计了全局依概率渐近稳定控制器、自适应逆最优控制器、输出反馈逆最优控制器以及在设计中如何处理二阶Hessian矩阵函数的方法，这种方法可同时获得控制律和自适应律，通过实例仿真，表明该控制算法是有效性的。

When the signal sources have different cycle frequencies, a method to estimate the optimal time lag is presented. It solves the severe problem that the conventional Cyclic MUSIC requires knowing the optimal time lag in computing the cyclic correlation matrix. A method of two-step search for DOA estimation by employing an interleaving technique and a Joint Estimation Strategy is developed to overcome the inadequency of signal sources with the same cycle frequency having no optimal time lag.

当信源的循环频率各不相同时，提出了一种估计最佳延时的方法，解决了传统Cyclic MUSIC算法计算循环相关矩阵需要已知最佳延时的问题；为克服多个具有相同循环频率信源不存在最佳延时的不足，利用交错技术和联合估计策略，提出了两步搜索估计DOA的方法。

The results showed that the optimal temperature for the growth of BY-3 was 30~ 40℃. And the optimal pH was 6~6.5. Besides, the optimal cultivated time was 36~52 h. The favorite carbon source included maltase, sucrose, mannitol, glucose, lactose, and so on.

拮抗菌BY-3菌株的研究 2.1 拮抗菌BY-3菌株生长特性的测定本研究确定了不同的温度、pH、营养条件及盐浓度对菌株BY-3生长的影响，并对其生长曲线作了测定。

Based on the fuzzy mathematics theory, the math model of the fuzzy optimal design for the gear reducer is set up and a computer optimal interface that gear optimal design plan is developed.

基于Pro/E的支撑平台，以Pro/TOOLKIT和MFC类库作为核心技术，提出了基于模糊优化设计理论的计算机辅助齿轮设计方案，结合模糊数学的基本原理，建立了齿轮传动模糊优化设计的数学模型，开发出一套计算机辅助齿轮优化设计的系统软件，分别给出了普通优化设计和模糊优化设计的计算结果，体现了模糊优化设计的优越性。

Through quantitative calculations of N600-16.7/537/537-Ⅰunit of a certain thermal power plant, the optimal initial pressure is obtained by method of exhaustion. It is the foundation of the optimal control in the whole power plant. The limitation of optimal operation curve provided by manufactory is also analyzed in this paper.

以某电厂N600-16.7/537/537-Ⅰ型汽轮机的运行数据进行计算，确定了可行压力区间，通过穷举法寻优得到最优初压，并分析了厂家提供的滑压运行曲线的局限性。

And control problems such as optimal import rate control, optimal harvesting control, optimal birth control are investigated. By means of nonlinear functional analysis, differential equations, integral equations, and modern control theory, a number of research results are obtained, which are theoretically valuable and provide a solid ground for the practical use of our models.

本文系统讨论了几类年龄依赖的单种群和多种群动力系统，综合应用非线性泛函分析、微分方程、积分方程以及分布参数系统控制论等理论与方法，深入地研究了这些系统的解的存在性、唯一性以及非负有界性；研究了这些种群动力系统的最优输入率、收获率和出生率控制问题，获得了一批重要的理论成果。

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％。