This paper presents an adaptive strategy for controlling chaotic systems. By employing the phase space reconstruction technique in nonlinear dynamical systems theory, the proposed strategy transforms the nonlinear system into canonical form, and employs a nonlinear observer to estimate the uncertainties and disturbances of the nonlinear system, and then establishes a state-error-like feedback law. The developed control scheme allows chaos control in spite of modeling errors and parametric variations. The effectiveness of the proposed approach has been demonstrated through its applications to two well-known chaotic systems: Duffing oscillator and Rössler chaos. 相似文献
This paper is about the progress of newly qualified teachers of English in London classrooms. Using a case‐study approach, it explores the ways teachers' knowledge of their subject is developed in specific situations and in relation to particular learners. In contrast to media representations of successful teaching that focus on questions of personality and inspiration, the picture of progress offered here is one of negotiation and accommodation, leading to fundamental change and to new understanding of the content and purposes of English. 相似文献
In Japan, there has been an increased concern about family and community participation in the childs education. Traditionally, the role of parents and community in Japan has been one of support and less one of active involvement in school learning. Since the government commenced education reforms in the last quarter of the 20th century, a more active role for parents and the community in education has been encouraged. These reforms have been inspired by the need to tackle various problems that had arisen, such as the perceived harmful elements of societys preoccupation with academic achievement and the problematic behavior of young people. In this paper, the following issues are examined: (1) education policy and reform measures with regard to parent and community involvement in the childs education; (2) the state of parent and community involvement at the eve of the 20th century. 相似文献
This article presents a framework and methodology for designing learning goals targeted at what students need to know and be able to do in order to attain high levels of literacy and achievement in three disciplinary areas—literature, science, and history. For each discipline, a team of researchers, teachers, and specialists in that discipline engaged in conceptual meta-analysis of theory and research on the reading, reasoning, and inquiry practices exhibited by disciplinary experts as contrasted with novices. Each team identified discipline-specific clusters of types of knowledge. Across teams, the clusters for each discipline were grouped into 5 higher order categories of core constructs: (a) epistemology; (b) inquiry practices/strategies of reasoning; (c) overarching concepts, themes, and frameworks; (d) forms of information representation/types of texts; and (e) discourse and language structures. The substance of the clusters gave rise to discipline-specific goals and tasks involved in reading across multiple texts, as well as reading, reasoning, and argumentation practices tailored to discipline-specific criteria for evidence-based knowledge claims. The framework of constructs and processes provides a valuable tool for researchers and classroom teachers' (re)conceptualizations of literacy and argumentation learning goals in their specific disciplines. 相似文献
This study explores the long-term impact on participation in the Linda Ray Intervention Program (LRIP) for children (n = 54) who were developmentally delayed and prenatally exposed to cocaine. By identifying a group of programme graduates from a high crime/high poverty neighbourhood in Miami-Dade County using ArcGIS 10.2 software, a quasi-experimental design was used to compare children living in this area who participated in the centre-based modality (5 h a day; 5 days a week) to children living in this area who participated in the home-based modality (3 h per week) on their Florida Comprehensive Assessment Test (FCAT) reading and math scale scores in public school. The children who participated in the centre-based modality reported stronger outcomes in both math and reading FCAT scale scores at the p < .05 level and also out-performed their school-age peers on both math and reading FCAT scores at the p < .05 level. 相似文献
The French orthographic code is complex, and its acquisition is laborious (Catach, 2008; Fayol & Jaffré, 2008). Three hypotheses attempt to explain orthographic knowledge acquisition (OKA). For some, exposure to the code leads to OKA through a self-learning process (Share, 2004). For others, OKA benefits from graphophonological processes (Coltheart, Rastle, Perry, Langdon, & Ziegler, 2001). Finally, some authors suggest that OKA is possible thanks to visual specific processes (Ans, Carbonnel, & Valdois, 1998). The main goal of this study was to test these hypotheses in a classroom context with comparable samples. In total, 143 2nd-grade children participated in this quasi-experimental study with a pretest, immediate posttest, and delayed posttest design. We assigned participants to one of four conditions. For three conditions, we created three teaching procedures based on each of the hypotheses: frequency of contacts with target words; explicit teaching of graphophonological properties of words; explicit teaching of visual properties of words. The fourth served as a control group. ANOVA analyses indicated that all three experimental conditions favored OKA, showing that the different teaching procedures led to spelling development. However, the visual condition was the most favorable. Three main conclusions can be drawn from this study: (a) models of OKA should account for the different paths that can lead to spelling acquisition; (b) visual properties of words and their acquisition need additional research, and (c) applied research in real classroom contexts is not only relevant for informing teaching practices but also for better understanding how learning takes place.