A combined time and frequency domain method for model reduction of discrete systems     

Chyi Hwang  Yen-Ping Shih  Ruey-Yinn Hwang 《Journal of The Franklin Institute》1981,311(6):391-402

A new combined time and frequency domain method for the model reduction of discrete systems in z-transfer function is presented. First, the z-transfer functions are transformed into the w-domain by the bilinear transformation, z = (1+w)/(1?w). Then, four model reduction methods—Routh approximation, Hurwitz polynomial approxima- tion, stability equation, and retaining dominant poles—are used respectively to reduce the order of the denominator polynomials in the w-domain. Least squares estimate is then used to find the optimal coefficients in the numerator polynomials of the reduced models so that the unit step response errors are reduced to a minimum. The advantages of the proposed method are that both frequency domain and time domain characteristics of the original systems can be preserved in the reduced models, and the reduced models are always stable provided the original models are stable.  相似文献   

Core Commitments and New Horizons     

Iris Tabak  Josh Radinsky 《学习科学杂志》2015,24(2):201-203

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Making agency matter: rethinking infant and toddler agency in educational discourse     

Iris Duhn 《Discourse: Studies in the Cultural Politics of Education》2015,36(6):920-931

This article engages critically with the concept of agency in infant and toddler educational discourse. It is argued that agency, when conceptualised with emphasis on individuality and the autonomous self, poses a conceptual ‘dead end’ for those who are not-yet-in-language, such as babies and toddlers. In considering agency as an aspect of becoming that is inherent in all matter, the article seeks to explore new pathways for conceptualising agency in infant and toddler education. Methodologically, the article aims to generate complex questions and, following Nigel Thrift's call, ‘wild ideas’, rather than solutions by addressing the relationship between discourse and matter to open up new spaces for thinking and doing ‘agency’ in education, for babies and toddlers and beyond.  相似文献   

Systematic Comparison of Decision Accuracy of Complex Compensatory Decision Rules Combining Multiple Tests in a Higher Education Context          下载免费PDF全文

Iris E. Yocarini  Samantha Bouwmeester  Guus Smeets  Lidia R. Arends 《Educational Measurement》2018,37(3):24-39

This real‐data‐guided simulation study systematically evaluated the decision accuracy of complex decision rules combining multiple tests within different realistic curricula. Specifically, complex decision rules combining conjunctive aspects and compensatory aspects were evaluated. A conjunctive aspect requires a minimum level of performance, whereas a compensatory aspect requires an average level of performance. Simulations were performed to obtain students' true and observed score distributions and to manipulate several factors relevant to a higher education curriculum in practice. The results showed that the decision accuracy depends on the conjunctive (required minimum grade) and compensatory (required grade point average) aspects and their combination. Overall, within a complex compensatory decision rule the false negative rate is lower and the false positive rate higher compared to a conjunctive decision rule. For a conjunctive decision rule the reverse is true. Which rule is more accurate also depends on the average test reliability, average test correlation, and the number of reexaminations. This comparison highlights the importance of evaluating decision accuracy in high‐stake decisions, considering both the specific rule as well as the selected measures.  相似文献   

PROSPECTIVE MEMORY TRAINING IN OLDER ADULTS     

Iris W. Schmidt  Ina J. Berg  Betto G. Deelman 《Educational gerontology》2013,39(6):455-478

This study evaluates the results of a training program for prospective remembering. The goal of the training was to improve prospective memory by associating cues from the retrieval situation with the to be remembered information. The training group consisted of 20 participants, aged between 45 and 81 years. The effects of strategy training were compared with those of an educational training group (N = 23 , age range 45-84) directed at reducing worries about forgetfulness, and a retest control group (N = 22 , age range 46-74). The educational training and retest control groups did not differ in demographic characteristics and test performance and were combined into one control group. Subjective evaluations revealed that subjects were very satisfied with the effects of training. This also was true for subjects in the educational training condition. The objective effects of training were evaluated with a telephone task which had to be performed in the daily life situation, and a prospective categorization task performed in the laboratory. Despite the low reliabilities of the prospective tasks, a significant but small effect of training compared to the combined control group was found on the sum score of prospective tests. The training effect was not related to age or pretraining performance level. At the three months follow-up, however, performance of the control group had increased to the level of the trained group. As expected, training effects did not generalize to other memory measures (assessed with tests for remembering names) or control measures (assessed with visuo-motor reaction time tests).  相似文献   

How Future Goals Enhance Motivation and Learning in Multicultural Classrooms     

Karen Phalet  Iris Andriessen  Willy Lens 《Educational Psychology Review》2004,16(1):59-89

This review examines the impact of future goals on motivation and learning in multicultural classrooms. Across cultures, schooling is a future-oriented investment. Studies of minority students' school achievement have advanced future goals as a crucial protective factor in the face of frequent school failure. At the same time, cultural discontinuities and limited opportunities in minority students' school careers may weaken the motivational force of the future. Our review of the seemingly contradictory evidence on the role of the future in minority students' school achievement calls for a more fine-grained motivational theory of the future. Specifically, converging findings support conceptual distinctions (a) between positive and negative perceptions of the instrumentality of school tasks for future goals, and (b) between internal and external regulation of classroom behaviour by future goals. Thus, positive instrumentality and internal regulation enhance intrinsic motivation and adaptive learning in multicultural classrooms. We conclude that the motivational force of future goals can be generalized to minority students and that it depends crucially on perceived instrumentality and internal regulation.  相似文献   

Approaches to learning of first-year and fifth-year student teachers: are there any differences?     

Iris Marušić  Ivana Jugović  Darko Lončarić 《欧洲师范教育杂志》2017,40(1):62-75

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The management and training needs of reception teachers working with the Foundation Stage Curriculum     

Elaine Hodson  Iris Keating 《International Journal of Early Years Education》2007,15(1):67-81

In England, since 2000, teachers of children aged three to five (the Foundation Stage) have been bound by the Curriculum Guidance for the Foundation Stage produced by central government. Initially, we were interested to learn of the responses of early years teachers to that document. We found that teachers welcomed the Curriculum Guidance, not least because it recognized that there exists a valuable and separate stage in children’s education. However, in relation to ensuring that quality learning experiences were provided, teachers identified two issues of concern to them—professional training of early childhood teachers, and the leadership and management of the Foundation Stage. Concerns also remained that not all stakeholders were yet aware of the needs of young children and of the staff training resources necessary to meet these needs. Upon our return to the respondents three years later, we found that, despite the incorporation of the Curriculum Guidance, some practitioners continued to feel that both colleagues and managers sometimes had limited understanding of the unique nature of the early childhood curriculum. Concerns about resources and an appropriate learning environment also continued to be evident.  相似文献   

The role of maternal mediation of writing to kindergartners in promoting literacy in school: A longitudinal perspective     

Aram  Dorit  Levin  Iris 《Reading and writing》2004,17(4):387-409

The current study follows up on Aram andLevin's (2001, Cognitive Development, 16, 831–852)analysis of the role of maternalwriting mediation among low SES Israelikindergartners. That study's main findingindicated that the quality of maternal writingmediation correlated concurrently withkindergartners' literacy skills aftercontrolling for socio-cultural measures. Thepresent study followed up the participants tothe second grade in school, and evaluated theirlevel of Spelling, Reading Comprehension, andLinguistic Knowledge two and a half years later. Theresults indicate that the children's literacymeasures in school were predicted by maternalwriting mediation in kindergarten beyond SESand the early literacy measures assessed in thekindergarten (Word Writing and LinguisticKnowledge). These results highlight thesignificance of early maternal writingmediation as a major factor in literacydevelopment.  相似文献   

Preparing inservice elementary science teachers: The role of the instructor’s site observations     

Dr. Iris M. Riggs 《Journal of Science Teacher Education》1995,6(1):20-26

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