基于Web of ScienceTM核心合集及CNKI数据库中收录的以该理论取向的二语发展研究为主题的国内外文献数据(1997—2017年),借用CiteSpace5.1绘制科学知识图谱,进行聚类分析、突变词分析、关键词分析,对比国内外该理论指导下二语动态发展...基于Web of ScienceTM核心合集及CNKI数据库中收录的以该理论取向的二语发展研究为主题的国内外文献数据(1997—2017年),借用CiteSpace5.1绘制科学知识图谱,进行聚类分析、突变词分析、关键词分析,对比国内外该理论指导下二语动态发展研究在核心领域与热点演进的共性与差异。研究发现近20年来国内外相关研究核心领域主要涉及理论内涵与方法论、学习者语言系统与学习者个体差异;研究热点演进路径均由理论建构到实证探究,国内多讨论混沌,国外则多关注涌现;国内相关研究发展较国外明显滞后,实证成果不足;教师身份、课堂环境及自主学习可拓展为国内研究的新热点。展开更多
The new chaos control method presented in this paper is useful for taking advantage of chaos.Based on sliding mode control theory, this paper provides a switching manifold controlling strategy of chaoticsystem, and...The new chaos control method presented in this paper is useful for taking advantage of chaos.Based on sliding mode control theory, this paper provides a switching manifold controlling strategy of chaoticsystem, and also gives a kind of adaptive parameters estimated method to estimate the unknown systems' pa-rameters by which chaotic dynamical system can be synchronized. Taking the Lorenz system as example, and with the help of this controlling strategy, we can synchronize chaotic systems with unknown parameters and different initial conditions.展开更多
If the measuring signals were input to the chaotic dynamic system as initial parameters, the system outputs might be in steady state, periodic state or chaos state. If the chaotic dynamic system outputs controlled in ...If the measuring signals were input to the chaotic dynamic system as initial parameters, the system outputs might be in steady state, periodic state or chaos state. If the chaotic dynamic system outputs controlled in the periodic states, the periodic numbers would be changed most with the signals. Our novel method is to add chaotic dynamic vibration to the measurement or sensor system.The sensor sensitivity and precision of a measurement system would be improved with this method. Chaotic dynamics measurement algorithms are given and their sensitivity to parameters are analyzed in this paper. The effects of noises on the system are discussed.展开更多
文摘基于Web of ScienceTM核心合集及CNKI数据库中收录的以该理论取向的二语发展研究为主题的国内外文献数据(1997—2017年),借用CiteSpace5.1绘制科学知识图谱,进行聚类分析、突变词分析、关键词分析,对比国内外该理论指导下二语动态发展研究在核心领域与热点演进的共性与差异。研究发现近20年来国内外相关研究核心领域主要涉及理论内涵与方法论、学习者语言系统与学习者个体差异;研究热点演进路径均由理论建构到实证探究,国内多讨论混沌,国外则多关注涌现;国内相关研究发展较国外明显滞后,实证成果不足;教师身份、课堂环境及自主学习可拓展为国内研究的新热点。
文摘The new chaos control method presented in this paper is useful for taking advantage of chaos.Based on sliding mode control theory, this paper provides a switching manifold controlling strategy of chaoticsystem, and also gives a kind of adaptive parameters estimated method to estimate the unknown systems' pa-rameters by which chaotic dynamical system can be synchronized. Taking the Lorenz system as example, and with the help of this controlling strategy, we can synchronize chaotic systems with unknown parameters and different initial conditions.
文摘If the measuring signals were input to the chaotic dynamic system as initial parameters, the system outputs might be in steady state, periodic state or chaos state. If the chaotic dynamic system outputs controlled in the periodic states, the periodic numbers would be changed most with the signals. Our novel method is to add chaotic dynamic vibration to the measurement or sensor system.The sensor sensitivity and precision of a measurement system would be improved with this method. Chaotic dynamics measurement algorithms are given and their sensitivity to parameters are analyzed in this paper. The effects of noises on the system are discussed.
