316 research outputs found
Farley-Ripple, Elizabeth N., A New Day for Education Research and Practice, Phi Delta Kappan, 102(April, 2021), 8-13.
No full textDescribes the way educational research gets used and how researchers and practitioners are working more closely together
A Self-Learning Solution for Torque Ripple Reduction for Non-Sinusoidal Permanent Magnet Motor Drives Based on Artificial Neural Networks
No full textThis paper presents an original method, based on artificial neural networks, to reduce the torque ripple in a permanent-magnet non-sinusoidal synchronous motor. Solutions for calculating optimal currents are deduced from geometrical considerations and without a calculation step which is generally based on the Lagrange optimization. These optimal currents are obtained from two hyperplanes. The study takes into account the presence of harmonics in the back-EMF and the cogging torque. New control schemes are thus proposed to derive the optimal stator currents giving exactly the desired electromagnetic torque (or speed) and minimizing the ohmic losses. Either the torque or the speed control scheme, both integrate two neural blocks, one dedicated for optimal currents calculation and the other to ensure the generation of these currents via a voltage source inverter. Simulation and experimental results from a laboratory prototype are shown to confirm the validity of the proposed neural approach.CPER Région Alsace 2007-201
The Use of Research in Schools: Principals’ Capacity and Contributions
No full textPolicy expectations for the role of research evidence in educational decision-making have grown exponentially in the U.S. and globally, yet there has been limited attention to school capacity to engage in evidence-informed improvement. In this paper, I address this gap by first conceptualizing principal leadership for evidence use and, second, use this conceptual lens to examine large-scale survey data about school evidence use practices and capacity. Drawing on data from a national survey of more than 4000 educators in 134 schools in the US, I explore school practices and capacity to use research and surface opportunities and needs for principal leadership in evidence-informed improvement. Findings suggest that there is an opportunity to improve the role of research in school improvement decision-making, and that principals may contribute to school capacity in specific ways that relate to developing human capital, influencing culture, leveraging resources, and shaping decision-making. Data reveal moderate evidence of research use in agenda setting and of organizational routines that support research use, but lack of uptake of those routines for research use as well as limited investment in resources (e.g., time). Further, decision-making was distributed across a wide range of improvement initiatives, with evidence of a lack of clarity about goals. Although principals report confidence and experience with using research, overall school staff also reported limited experience with prior research, including coursework or participation in research, and low confidence in critically consuming research. Implications point to the need to strengthen principals’ own evidence use capacity as well as focus on dimensions school capacity as part of evidence use initiatives. Recommendations suggest strategies for developing principals’ knowledge and skills around leadership for evidence-informed improvement
Mapping the community : use of research evidence in policy and practice
No full textAbstract: The use of research evidence (URE) in policy and practice is relevant to many academic disciplines, as well as policy and practice domains. Although there has been increased attention to how such evidence is used, those engaged in scholarship and practice in this area face challenges in advancing the field. This paper attempts to “map the field” with the objective of provoking conversation about where we are and what we need to move forward. Utilizing survey data from scholars, practitioners, and funders connected to the study of the use of research evidence, we explore the extent to which URE work span traditional boundaries of research, practice, and policy, of different practice/policy fields, and of different disciplines. Descriptive and network analyses point to the boundary spanning and multidisciplinarity of this community, but also suggest exclusivity, as well as fragmentation among disciplines and literatures on which this work builds. We conclude with opportunities for to improve the connectedness, inclusiveness, relationship to policy and practice, and sustainability of URE scholarship
Flow Ripple Reduction in Reciprocating Pumps by Multi-Phase Rectification
No full textReciprocating piezoelectric micropumps enable miniaturization in microfluidics for lab-on-a-chip applications such as organs-on-chips (OoC). However, achieving a steady flow when using these micropumps is a significant challenge because of flow ripples in the displaced liquid, especially at low frequencies or low flow rates (<50 µL/min). Although dampers are widely used for reducing ripples in a flow, their efficiency depends on the driving frequency of the pump. Here, we investigated multi-phase rectification as an approach to minimize ripples at low flow rates by connecting piezoelectric micropumps in parallel. The efficiency in ripple reduction was evaluated with an increasing number (n) of pumps connected in parallel, each actuated by an alternating voltage waveform with a phase difference of 2π/n (called multi-phase rectification) at a chosen frequency. We introduce a fluidic ripple factor ((Formula presented.)), which is the ratio of the root mean square ((Formula presented.)) value of the fluctuations present in the rectified output to the average fluctuation-free value of the discharge flow, as a metric to express the quality of the flow. The fluidic ripple factor was reduced by more than 90% by using three-phase rectification when compared to one-phase rectification in the 2–60 μL/min flow rate range. Analytical equations to estimate the fluidic ripple factor for a chosen number of pumps connected in parallel are presented, and we experimentally confirmed up to four pumps. The analysis shown can be used to design a frequency-independent multi-phase fluid rectifier to the desired ripple level in a flow for reciprocating pumps.Micro and Nano EngineeringPrecision and Microsystems Engineerin
A Fractional-N Digitally Intensive PLL Achieving 428-fs Jitter and <-54-dBc Spurs Under 50-mV <sub>pp</sub>Supply Ripple
No full textIn this article, we present a 4.5-5.1-GHz fractional-N digitally intensive phase-locked loop (DPLL) capable of maintaining its performance in face of a large supply ripple, thus enabling a direct connection to a switched-mode dc-dc converter. Supply pushing of its inductor-capacitor (LC) oscillator is suppressed by properly replicating the supply ripple onto the gate of its tail current transistor, while the optimum replication gain is determined by a new on- chip calibration loop tolerant of supply variations. A proposed configuration of cascading a supply-insensitive slope generator with an output of a current digital-to-analog converter (DAC) linearly converts the phase error timing into a corresponding voltage, which is then quantized by a successive approximation register (SAR) analog-to-digital converter (ADC) to generate a digital phase error. We also introduce a low-power ripple pattern estimation and cancellation algorithm to remove the phase error component due to the supply-induced delay variations of loop components. Implemented in 40-nm CMOS, the DPLL prototype achieves the performance of 428-fs rms jitter, <-55-dBc fractional spur, and <-54-dBc maximum spur while consuming 3.25 mW and being subjugated to a sinusoidal or sawtooth supply ripple of 50 mVpp at 50-MHz reference divided by 3, 6, or 12.ElectronicsQCD/Sebastiano La
Intellectual Space in Naguib Mahfouz???s Thartharah fawq al-N??l
No full textFaculty Mentor: Dr. F. Elizabeth Dahab\ud
Department of Comparative Literature and ClassicsPost-independence Egypt experienced a mass economic nationalization headed by President Nasser; the resulting emergence of an authoritarian socialist government became a source of alienation for the intelligentsia. Distinguished scholar Roger Allen states that Nobel laureate Naguib\ud
Mahfouz???s 1966 novel Thartharah fawq al-N??l ???depict[s] the role and\ud
fate of the Egyptian cultural intelligentsia during the 1960s??? (107). Employing literary, theoretical, and historical scopes, this paper investigates the way Mahfouz accomplishes this, specifically in his construction of internal and external environments. From the physical stature of the novel being shorter in length than those from his earlier period, to the confined setting of the houseboat where the majority of the story takes place, the reader experiences a constricted feeling perhaps similar to that of the intelligentsia under Nasser???s socialist regime. On an internal level, the numerous mental evocations by Mahfouz???s main character involve a vast historical spectrum. Moreover, the constantly shifting currents of his stream of consciousness serve to relocate and dislocate the reader. This multi-layered analysis of the author???s spatial construction of both internal and external environments promotes a deeper understanding of both Mahfouz???s artistry and the reality for the Egyptian intellectual in the 1960s
Strategic approaches to science and technology in development
No full textWatson, Crawford, and Farley examine the ways in which science and technology (S&T) support poverty alleviation and economic development and how these themes have been given emphasis or short shrift in various areas of the World Bank's work. Central to their thesis is the now well-established argument that development will increasingly depend on a country's ability to understand, interpret, select, adapt, use, transmit, diffuse, produce, and commercialize scientific and technological knowledge in ways appropriate to its culture, aspirations, and level of development. The authors go beyond this tenet, analyzing the importance of S&T for development within specific sectors. They present policy options for enhancing the effectiveness of S&T systems in developing countries, review previous experience of the World Bank and other donors in supporting S&T, and suggest changes that the World Bank and its partners can adopt to increase the impact of the work currently undertaken in S&T. The authors'main messages are: 1) S&T has always been important for development, but the unprecedented pace of advancement of scientific knowledge is rapidly creating new opportunities for and threats to development. 2) Most developing countries are largely unprepared to deal with the changes that S&T advancement will bring. 3) The World Bank's numerous actions in various domains of S&T could be more effective in producing the needed capacity improvements in client countries. 4) The World Bank could have a greater impact if it paid increased attention to S&T in education, health, rural development, private sector development, and the environment. The strategy emphasizes four S&T policy areas: education and human resources development, the private sector, the public sector, and information communications technologies.Public Health Promotion,Environmental Economics&Policies,ICT Policy and Strategies,Decentralization,Health Economics&Finance,Environmental Economics&Policies,ICT Policy and Strategies,Health Economics&Finance,Poverty Assessment,Agricultural Research
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