基于形态学的西班牙语和中文中“时”的对比研究

本文采用语言对比分析的研究方法,就西班牙语和中文的“时”进行了微观层面的分析和比较。具体而言,文章总结了两种语言中关于“时”的称谓、概念、所属范畴、分类和表达方式的异同之处。通过比较发现,在西班牙语中,“时”被称为“时态(tiempo)”,而在中文中被称为“时制”。两种语言中“时”在语法范畴中的概念相似;但是,西语的时态属于严格的语法范畴,而关于中文时制的研究通常也涉及词汇或语义范畴。此外,在“时”的分类上,当以时间参照为分类基准时,两种语言有相似之处,但西班牙语通常以形态变化作为分类标准。最后,在“时”的表达方式上,两种语言都会借助词汇手段来传达语义信息,但西班牙语通过动词形态的屈折变化来标记时态,而中文通常使用助词作为时制标记。

H_∞ reference tracking control design for a class of nonlinear systems with time-varying delays

This paper investigates the H∞ trajectory tracking control for a class of nonlinear systems with time- varying delays by virtue of Lyapunov-Krasovskii stability theory and the linear matrix inequality （LMI） technique. A unified model consisting of a linear delayed dynamic system and a bounded static nonlinear operator is introduced, which covers most of the nonlinear systems with bounded nonlinear terms, such as the one-link robotic manipulator, chaotic systems, complex networks, the continuous stirred tank reactor （CSTR）, and the standard genetic regulatory network （SCRN）. First, the definition of the tracking control is given. Second, the H∞ performance analysis of the closed-loop system including this unified model, reference model, and state feedback controller is presented. Then criteria on the tracking controller design are derived in terms of LMIs such that the output of the closed-loop system tracks the given reference signal in the H∞ sense. The reference model adopted here is modified to be more flexible. A scaling factor is introduced to deal with the disturbance such that the control precision is improved. Finally, a CSTR system is provided to demonstrate the effectiveness of the established control laws.