共查询到20条相似文献，搜索用时 156 毫秒
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1Introduction AGalton Watsonbranchingprocessinrandom environments[13]isageneralizationofstandardGalton Watsonbranchingprocesses.Itwasfirstformulatedby SmithandWilknson[1]inthespecificcasewheretheen vironmentalprocessisi.i.d.randomvariables.The structureof… 相似文献
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As a parallel programming model, Map-Reduce is used for distributed computing of massive data. Map-Reduce model encapsulates
the details of parallel implementation, fault-tolerant processing, local computing and load balancing, etc., provides a simple but powerful interface. In case of having no clear idea about distributed and parallel programming, this
interface can be utilized to save development time. This paper introduces the method of using Hadoop, the open-source Map-Reduce
software platform, to combine PCs to carry out scalable parallel computing. Our experiment using 12 PCs to compute N-body problem based on Map-Reduce model shows that we can get a 9.8x speedup ratio. This work indicates that the Map-Reduce can be applied in scalable parallel computing. 相似文献
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Olga Kunina‐Habenicht André A. Rupp Oliver Wilhelm 《Journal of Educational Measurement》2012,49(1):59-81
Using a complex simulation study we investigated parameter recovery, classification accuracy, and performance of two item‐fit statistics for correct and misspecified diagnostic classification models within a log‐linear modeling framework. The basic manipulated test design factors included the number of respondents (1,000 vs. 10,000), attributes (3 vs. 5), and items (25 vs. 50) as well as different attribute correlations (.50 vs. .80) and marginal attribute difficulties (equal vs. different). We investigated misspecifications of interaction effect parameters under correct Q‐matrix specification and two types of Q‐matrix misspecification. While the misspecification of interaction effects had little impact on classification accuracy, invalid Q‐matrix specifications led to notably decreased classification accuracy. Two proposed item‐fit indexes were more strongly sensitive to overspecification of Q‐matrix entries for items than to underspecification. Information‐based fit indexes AIC and BIC were sensitive to both over‐ and underspecification. 相似文献
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The purpose of this study is to examine faculty’s views about the move from face-to-face (F2F) instruction to online due to the COVID-19 pandemic. The researcher used Q methodology [Q], a mixed method, to determine and describe faculty views about this situation. The participants sorted 36 statements to reveal and describe their subjective viewpoints. In Q, similar sorts are grouped together mathematically into factors, each representing a unique viewpoint. The Q-sorting process is reflective and self-referent. The operation of sorting items allows participants to provide their internal viewpoint. This is different from responding to a Likert-type survey. Additionally, the analyses allow for differentiation of views rather than an aggregate of views. Each unique viewpoint is described by a representative sort, distinguishing statements, and participants’ post-sort responses. Three views emerged: Techies who like to teach (the view most positive in relation to teaching online); Overwhelmed as human beings (populated by caregivers); and It’s about what cannot be done online (those who are focused on the limitations of technology and abilities for online instruction). Generally, faculty felt frustrated with their ability to best support their students within the online format. Administrators should consider the results of this study to better understand the instructional and mental-health needs of faculty especially in an emergency situation, such as COVID-19. The findings indicate that creating the best learning situations for students is not one-size-fits-all and that there are discipline and pedagogical issues to consider when moving F2F courses online that are not fixed simply with technology.
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Across the disciplines of psychology, the research to practice gap is gaining recognition. This study used an integrated knowledge translation (iKT) framework to evaluate the acceptability, feasibility, and sustainability of delivering an anxiety intervention for children with autism spectrum disorders (i.e., FYF), in schools. Five participants (three educators and two parents) offered their perspectives on program strengths, barriers to implementation, and adaptations for the school setting. Qualitative data were collected through focus group discussions and analyzed using thematic analysis techniques. The participants provided valuable information about program structure and considerations for implementation in schools. Results indicated that participants found the proposed modified FYF to be acceptable and feasible and recommended pilot testing the intervention. Specific recommendations for adaptations are discussed. This study offers a model for researchers to collaborate with key stakeholders in adapting interventions for use in schools, thereby, bridging the gap between research and practice. 相似文献
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This paper describes a general model for skills instruction and its implementation through the program “Scientific Communication” for acquiring learning skills. The model is characterized by modularity, explicit instruction, spiral integration into contents, practice in various contexts, and implementation in performance tasks. It requires flexible planning and implementation by the teachers. The study investigated how science teachers implemented this model for a two-year period. Results show that they coped with this task by customizing the program; they underwent a positive change in perceptions about skills instruction, instructional models, using instructional materials, influence and involvement in school and beyond. 相似文献
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Kenneth Leithwood 《教育政策杂志》2013,28(3):377-398
Government‐initiated school restructuring began in the Canadian province of British Columbia in 1989. It was accompanied by significant commitments of new funding for schools and high levels of awareness on the part of central officials about the requirements for effective policy implementation. The content of this restructing mirrored efforts in many other jurisdictions but was exceptionally comprehensive. Results of a four‐year study which examined the processes and consequences of restructuring in local schools are summarized in this paper. The paper identifies six key lessons about productive restructuring processes and outlines a promising image of schools capable of such restructuring. Also proposed is an ‘educative’ approach by governments toward educational reform policy and its implementation. 相似文献
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Background and objectives: Although randomized controlled trials (RCTs) have been performed to alleviate loneliness among older people, little is known about how they have been implemented, or whether they are effective in real life. Our RCT-based model, “Circle of Friends” (CoF) proved to be effective in improving the wellbeing, health and cognition of lonely older people. Over 10 years we have systematically trained 752 professional facilitators of lonely older people’s CoF groups. This study aims to explain how this training has succeeded in practice and to describe the outcomes of CoF implementation. Research Design and Methods: Survey data were gathered in 2006–2016 from trained facilitators (n = 319) and CoF participants (n = 1041). Results: The CoF has been disseminated in 80 municipalities in Finland. The trained CoF facilitators have maintained the original key elements and structure of the model fairly well in its implementation and dissemination processes. The main objectives of CoF – the alleviation of loneliness, making new friends, and members continuing meetings on their own – have remained the facilitators’ priority. The CoF socially activates older participants, as 67% organized group meetings after the facilitated process. However, the CoF has become diluted in some aspects during its dissemination, as a small proportion of trained facilitators have implemented the model in their own way. Discussion and Implications: The CoF may be an encouraging example of how an original RCT model with a rigorous training program can be implemented and disseminated in real-life settings over 10 years. 相似文献
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In this paper, a unified matrix recovery model was proposed for diverse corrupted matrices. Resulting from the separable structure of the proposed model, the convex optimization problem can be solved efficiently by adopting an inexact augmented Lagrange multiplier (IALM) method. Additionally, a random projection accelerated technique (IALM+RP) was adopted to improve the success rate. From the preliminary numerical comparisons, it was indicated that for the standard robust principal component analysis (PCA) problem, IALM+RP was at least two to six times faster than IALM with an insignificant reduction in accuracy; and for the outlier pursuit (OP) problem, IALM+RP was at least 6.9 times faster, even up to 8.3 times faster when the size of matrix was 2 000×2 000. 相似文献
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H.H. Tillema 《欧洲师范教育杂志》1997,20(3):283-296
This paper presents an approach to belief change in teacher education programmes. Although belief change may constitute a more relevant goal for initial teacher education than knowledge transmission and competence attainment per se, relatively few models or methods have been put forward that can help student teachers to become aware of, knowledgeable about, and actively involved in changing and (re) constructing their own teaching beliefs. The model of study teams is presented as a relevant approach to teaching in teacher education, together with some preliminary evaluations regarding its implementation. It shows that utilising study teams can have a strong impact on teacher education programmes as well as on student teachers’ thinking. 相似文献
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In the United Kingdom, curricular music education has seen two main waves of development and is in the process of shaping a third. Ideas from the second wave have maintained theoretical dominance to the present day, despite the concerns expressed by some about their practical implementation. This paper suggests that problems with the implementation of second-wave ideas have been caused by hermeneutic complexities inherent to the word ‘music’ as well as by an ongoing ideological debate about the proper purpose of music education. It is proposed here that by approaching musical learning in the emergent third wave through the sub-discipline of ‘music theatre’ – and by conceiving that term in its broadest sense – this interpretive difficulty can be avoided whilst many practical advantages may be reaped. The notion of music theatre as a key component of music education's third wave is explored alongside its theoretical prerequisites, and a number of questions are identified for further consideration. 相似文献
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提出了一种带有冗余项的多行选址驱动算法及电路实现方案,其适用于液晶显示驱动芯片。算法通过在行调制矩阵中增加冗余行,在显示数据矩阵中增加冗余数据,从而减少了列驱动电平数。此外,还提出了本算法的实现电路。实验结果表明,在液晶显示驱动芯片中,该算法能降低30%的驱动功耗。 相似文献
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MRI and PET images fusion based on human retina model 总被引：1，自引：0，他引：1
DANESHVAR Sabalan GHASSEMIAN Hassan 《浙江大学学报(A卷英文版)》2007,8(10):1624-1632
The diagnostic potential of brain positron emission tomography (PET) imaging is limited by low spatial resolution. For solving this problem we propose a technique for the fusion of PET and MRI images. This fusion is a trade-off between the spectral information extracted from PET images and the spatial information extracted from high spatial resolution MRI. The proposed method can control this trade-off. To achieve this goal, it is necessary to build a multiscale fusion model, based on the retinal cell photoreceptors model. This paper introduces general prospects of this model, and its application in multispectral medical image fusion. Results showed that the proposed method preserves more spectral features with less spatial distortion. Comparing with hue-intensity-saturation (HIS), discrete wavelet transform (DWT), wavelet-based sharpening and wavelet-à trous transform methods, the best spectral and spatial quality is only achieved simultaneously with the proposed feature-based data fusion method. This method does not require resampling images, which is an advantage over the other methods, and can perform in any aspect ratio between the pixels of MRI and PET images. 相似文献
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提出P-除环上矩阵的广义逆的概念,证明了除环Q上秩为r的任何m×n矩阵A,必存在唯一的一个广逆B等结论. 相似文献
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Qiu Zhao Kongsheng Chen Meizhong Chen Bruno Briseghella Zhiyong Guo Guotao Yang 《天津大学学报(英文版)》2018,(5)
The blind-hole method is the most widely used approach to experimentally determine the distribution of residual stress. This paper aims to improve test accuracy of welding residual stress and conducts an experimental study on the strain release factors involved when using the blind-hole method for Q235 and Q345, two steels commonly used in building structures. The ranges of strain release factors A and B in the elastic stage, the effects of strain release factors on residual stress calculated values, and the plastic corrected strain release factors are analyzed considering of the effect of plastic deformation around the blind hole on measurement accuracy. Finally, a simplified calculation formula to determine strain release factors is proposed for use with the blind-hole method. Results show that in the elastic stage, strain release factor A for Q235 and Q345 ranges from-0.399 to-0.525 and strain release factor B from-0.791 to-0.960. Changing the strain release factors A and B shows that calculated residual tensile stress varies in relation to a decrease in both factor values. However, there is a increase in calculated residual compressive stress with a decrease in the strain release factor A value, but there is an decrease with a decrease in strain release factor B value. Calculated residual stress applied to elastic strain release factors is compared with that applied to amended plastic strain release factors for Q235 steel. The maximum deviation between calculated residual stress and test stress is reduced from 21.1 to 1.0%,and for Q345 steel from 26.5 to 1.2%. It is thus evident that the plastic correction formula proposed in this paper can be used in calculations when conducting a residual stress test. 相似文献
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整体听写教学法是在听力教学法衍生的一种结合了听、说、读、写能力训练的综合教学法。本文研究在合作学习环境下如何运用整体听写教学法提高二语学习者的听说能力,详细描述了整体听写的具体过程和理论背景,陈述整体听写法的优势及有待补充和完善的不足之处。 相似文献
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Quasi-Newton methods are the most widely used methods to find local maxima and minima of functions in various engineering practices. However, they involve a large amount of matrix and vector operations, which are computationally intensive and require a long processing time. Recently, with the increasing density and arithmetic cores, field programmable gate array (FPGA) has become an attractive alternative to the acceleration of scientific computation. This paper aims to accelerate Davidon-Fletcher-Powell quasi-Newton (DFP-QN) method by proposing a customized and pipelined hardware implementation on FPGAs. Experimental results demonstrate that compared with a software implementation, a speed-up of up to 17 times can be achieved by the proposed hardware implementation. 相似文献
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以土木工程专业卓越工程师的培养标准和能力实施矩阵为出发点,结合土木工程专业结构工程课程群的课程设计环节,将各门课程设计有机组合,构建成若干个CDIO模式的二级项目,实现以工程项目为导向的工程教学模式,使学生得到构思、设计、实现、评价的一系列工程训练。分析了土木工程专业结构工程类课程间的相互关联性,设计了两个CDIO二级项目,并提出了项目的实施过程和需要解决的问题。 相似文献
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We argue in this article that student teachers’ anxiety about computers can be properly understood only through an examination of cultural and historical antecedents concerning fears of technology. This perspective provides us with a context to examine the development, implementation and evaluation of a computer education course for student teachers over a 2‐year period. The results of the evaluation indicate that the methods adopted have been successful in promoting computer literacy and reducing computer anxiety. The empirically‐based approach to course development and evaluation adopted in this study provides a model for other tertiary educators. 相似文献