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An algorithm for constructing a black box model of the sinusoidal input/steady-state response behavior of nonlinear time-invariant systems over a set of frequencies and amplitudes is presented. It is assumed that the steady-state response is periodic of the same fundamental frequency as the excitation, and that the Fourier coefficients are continuous functions of amplitude and square-integrable functions of frequency. The algorithm converges, in a mean-square sense, to an exact representation of the first N harmonics of the steady-state response minus its d.c. component. The model constructed by the algorithm admits a relatively simple physical realization characterized by 2NM+1 linear dynamic elements, and N(2M+1)+1 nonlinear static elements. The underlying mathematical structure of the model is an orthogonal series expansion relative to time whose coefficients are themselves truncated orthogonal expansions relative to frequency. Here M, the number of harmonics used for frequency interpolation, is determined by the algorithm. Of the N(2M+1)+1 memoryless nonlinearities which characterize the model, N of these are specified ahead of time (Tchebysheff polynomials), and 2NM+1 are parameters which mold the representation to the specific system being modeled. Each of these functions of a single variable can be obtained in a pointwise manner directly from steady-state measurements. The algorithm was implemented on a digital computer, and forced versions of the classic equations of van der Pol and Duffing were run as examples. An additional analytic example of a frequency multiplier of prescribed bandwidth was also presented. 相似文献
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Allan B. de Guzman Rona Denise V. Coronel Kannerin O. Chua Mariz G. Constantino Ericsann James C. Cordova 《Educational gerontology》2013,39(4):358-377
Geriatric nursing is a physically and emotionally demanding job in healthcare. It is a neglected field despite the growing population of the elderly, and the experiences of geriatric nurses are one of the unrecognized aspects of this field. This qualitative study purports to explore the successes and struggles of the lived experiences of a select group of Filipino geriatric nurses working in nursing homes. A total of five registered nurses selected from Philippine geriatric homes were the subjects of this qualitative study. Data were gathered from a two-part instrument: namely, a researcher-made robotfoto and a semistructured interview. Through the use of a repertory grid involving both cool and warm analyses, field texts were phenomenologically reduced in order to establish distinct conceptual clusters. Summarily, two roles were found to be the defining elements of Filipino geriatric care nurses' sense of success and fulfillment. These include the instrumental and developmental, which describe the nurses' appreciation of their unique place in the lives of their elderly patients and, at the same time, their experiences of personal and professional growth and expansion as nurses. In regard to their struggles, the contextual conditions in the workplace typify the roadblocks of their efficient and effective delivery of quality healthcare services. 相似文献
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Salleh Hairon Jonathan Wee Pin Goh Catherine Siew Kheng Chua 《School Leadership & Management》2015,35(2):163-182
Professional learning communities (PLCs) have gained considerable attention in education. However, PLCs are dependent on how group members collectively work and learn towards shared goals on improving teaching and learning. This would require leadership to support meaningful and productive interactions within PLC contexts, and hence, the importance of teacher leaders. In this article, we report on an ethnographic case study involving three PLCs investigating how teacher leadership supports PLC conversations using an intervention framework provided by the research team. The findings showed that teacher leadership has potential in supporting PLC conversations along three dimensions of its construct. 相似文献
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AbstractPolitical and historical thoughts pertaining to “modern Malaya” and Malaysia are phenomena of the emerging modern era characterized by the stirrings and the rise of nationalism in Southeast Asia since the early twentieth century. One of the most compelling ideas in envisioning the nation and fighting for independence then was Melayu Raya, articulated by a group of visionary leaders of socio-political movements who professed to fight for the creation of a political entity, a new independent “nation.” Using the history of ideas approach, this article argues that nations are envisioned, and that we need to contextualize the discussion within what has been termed as “Malay world,” the old kingdoms in the region, and the subsequent struggles against colonial powers and the “nationalist” projects for independence. To help understand this background, the article uses the concept of “culture zone” as used by Fernand Braudel in his study of civilizations. This article examines the debate on the “Malay world” and Melayu Raya, and also the post-Second World War envisioning of the nation and the approaches taken by various groups to fight against British colonialism and for independence. Despite almost six decades of independence, some of these ideas keep returning, resonating with some aspects of the present in today's Malaysia. In the course of this article, a brief reference to the history of ideas and the idea of history is made. 相似文献
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YaoHui K. Chua Raymond K.K. Quek 《Sports biomechanics / International Society of Biomechanics in Sports》2017,16(1):13-22
This study aimed (1) to profile the plantar loading characteristics when performing the basketball lay-up in a realistic setting and (2) to determine the number of trials necessary to establish a stable mean for plantar loading variables during the lay-up. Thirteen university male basketball players [age: 23.0 (1.4) years, height: 1.75 (0.05) m, mass: 68.4 (8.6) kg] performed ten successful basketball lay-ups from a stationary position. Plantar loading variables were recorded using the Novel Pedar-X in-shoe system. Loading variables including peak force, peak pressure, and pressure–time integral were extracted from eight foot regions. Performance stability of plantar loading variables during the take-off and landing steps were assessed using the sequential averaging technique and intra-class correlation coefficient (ICC). High plantar loadings were experienced at the heel during the take-off steps, and both the heel and forefoot regions upon landing. The sequential estimation technique revealed a five–eight trial range to achieve a stable mean across all plantar loading variables, whereas ICC analysis was insensitive to inter-trial differences of repeated lay-up performances. Future studies and performance evaluation protocols on plantar loading during basketball lay-ups should include at least eight trials to ensure that the measurements obtained are sufficiently stable. 相似文献
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This article reports findings from a classroom environment study which was designed to investigate the nature of Chinese Language
classroom environments in Singapore secondary schools. We used a perceptual instrument, the Chinese Language Classroom Environment
Inventory, to investigate teachers’ and students’ perceptions towards their Chinese Language classroom learning environments
using six dimensions, namely, Student Cohesiveness, Teacher Support, Involvement, Cooperation, Task Orientation and Equity.
The investigation was carried out using a sample of 1,460 secondary three (Grade 9) students from 50 Chinese Language classes
in 25 Singapore government secondary schools. The nature of the Chinese Language classroom learning environments was interpreted
from analyses of the perception scores obtained, as well as from various comparisons of the perception scores between different
groups. Although both the Chinese Language teachers and students perceived their present classroom learning environments positively,
they would like improvements in all the six dimensions of the classroom learning environments under investigation. Also teachers
perceived a more positive classroom learning environment than their students in the same class. In addition, female students
perceived their actual and preferred classroom environments more positively than their male counterparts. 相似文献