The Effects of a Large Scale Mastery Environment on Students’ Self-Concept

The Tennessee self-concept scale was used to measure the self-concept of eighty-eight college freshmen at the end of their first semester in college. Forty-four of these students had been randomly assigned to a large scale mastery learning environment, and the other forty-four were randomly assigned to conventional classes. “T-test” ratios indicate that the mastery learning students have higher self-concepts than do their conventional counterparts.     

Simulation And Optimization of Electric Vehicle＇s Dynamic Performance

利用基于MATLAB/Simulink的电动汽车仿真软件建立整车的动力性能仿真模型,根据建立的模型对电动汽车的动力性能进行了分析.使用ADVISOR软件中的Autosize部分对主要的参数进行了优化,缩短了开发周期,降低了设计成本.     

Performance of a Large Mat Foundationon Soft Rock

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Dynamic Behavior of a New Hydraulic Steel Gate

A new style of hydraulic steel gate based on the principle of bionics is proposed in this paper. It has a fish-like shape and consists of right arches, invert arches, connection components and a face plate. It would be first applied in the project of Caoe River Sluice, used as both tidal barrage and flood gate. Compared with conventional hydraulic steel gate of beam grids, this new style of hydraulic steel gate can save up to 30%-50% of steel consumption. The dynamic behavior of the new gate under the impact load of tidal bore is investigated. The impact load of tidal bore is considered by a load spectrum obtained by field observation over a long period of time. Then a numerical analysis of the gate under the load spectrum is carried out by finite element method. The fluid-structure interaction is considered in the analysis. And a comparison between the response of the gate under the impact load and the response of the gate under the corresponding static load is conducted and indicates that the gate has a dynamic magnification factor of 1.2.     

Teachers’ Experience of Working with Socio-scientific Issues: A Large Scale and in Depth Study

The research is an investigation of teachers’ experience of working with socio-scientific issues (SSI). A large group of teachers (55) chose one of six cases with the characteristics of SSI and were free to organize the work as they found appropriate. The research focuses on how teachers chose content, organized their work and experienced the students’ interest and learning. The teachers answered a questionnaire after working with the cases and seven of them were interviewed to provide in-depth understanding of issues raised in the questionnaire. The teachers found the SSI to be current topics with interesting content and relevant tasks and they felt confident about the work. They were quite content with the students’ learning of scientific facts, how to apply scientific knowledge and to search for information. However, they found that the students did not easily formulate questions, critically examine arguments or use media to obtain information about the task. The interviewed teachers did not find this work new, but they organized it as ‘a special event’. They understood SSI work as ‘free’ work and group work was frequent, but only a few of the teachers developed explicit strategies for teaching SSI. They had different ideas about learning but they all talked about knowledge as a set of facts to be taken in by the students. They all included elements of SSI but mostly to introduce the regular science content. However the teachers started to reflect upon the potential of using SSI to cover more goals in the curriculum.     

Is Teacher Value Added a Matter of Scale? The Practical Consequences of Treating an Ordinal Scale as Interval for Estimation of Teacher Effects

Research shows that assuming a test scale is equal-interval can be problematic, especially when the assessment is being used to achieve a policy aim like evaluating growth over time. However, little research considers whether teacher value added is sensitive to the underlying test scale, and in particular whether treating an ordinal scale as interval might lead to erroneous conclusions about teacher quality. This article addresses the issue by estimating teacher value added, then applying extremely mild nonlinear transformations to the original scale and re-estimating the value added. Although by definition at most one of these scales can be equal-interval, all are treated as if interval-scaled when estimating value added. Results show that value added is sensitive to the scale used. While rank orderings of teachers do not change radically by transformation, even mild departures from the original scale can change a teacher’s odds of being considered high- or low-performing by a factor of 5.     

Simulation of Blast and Fragment Loading Using a Coupled Multi-Solver Approach

Simulating blast and fragment loading simultaneously in a single computation requires the combined use of multiple states of the art solvers. A pipe bomb is an example of simple improvised explosive device （IED） that consists of a piece of pipe filled with explosive material and capped at both ends. To simulate the explosion of a pipe bomb and the damage it causes, a coupled multisolver approach based upon finite element and finite volume methods is applied. The numerical calculation presented demonstrates the ability of ANSYS AUTODYN to correctly simulate the threats of IEDs and provides insight into how the most significant physical phenomena affect the results.     

Zooming in Time—Exploring Students’ Interpretations of a Dynamic Tree of Life

Journal of Science Education and Technology - Central to evolution is the concept of a common ancestry from which all life has emerged over immense time scales, but learning and teaching temporal...     

Dynamic responses of a multilayer piezoelectric hollow cylinder under electric potential excitation

INTRODUCTION Recently, more and more investigations have been conducted on multilayer piezoelectric media. Kharouf and Heyliger (1994) and Heyliger and Ra- mirez (2000) dealt with the free vibration problems of laminated piezoelectric cylinders and discs, respec- tively. Chen (2000) considered the free vibration of (multilayer) nonhomogeneous piezoceramic hollow spheres by employing a separation formulation for displacements. Chen (2001) developed a state-space method for free vibration …     

一种改进协同过滤推荐算法

在传统的协同过滤推荐算法基础上,对传统协同过滤算法中冷门物品不能进行处理问题进行剖析,提出一种改进的协同过滤推荐算法。通过实验仿真,验证了该算法的有效性。     

一种变步长LMS自适应滤波算法及分析

讨论了变步长自适应滤波算法,给出了一种新的变步长LMS自适应算法,建立了步长因子μ与迭代次数n及输入信号之间的一种新的非线性函数关系。该算法与传统LMS算法相比,在计算量增加不太大的情况下,具有更快的收敛速度和较小的稳态误差,而且无须去关心步长因子的大小。通过Matlab模拟仿真的结果与理论分析相一致,证实了该算法的优越性。     

Modified Adaptive Weighted Averaging Filtering Algorithm for Noisy Image Sequences

In order to avoid the influence of noise variance on the filtering performances, a modified adaptive weighted averaging (MAWA) filtering algorithm is proposed for noisy image sequences. Based upon adaptive weighted averaging pixel values in consecutive frames, this algorithm achieves the filtering goal by assigning smaller weights to the pixels with inappropriate estimated motion trajectory for noise. It only utilizes the intensity of pixels to suppress noise and accordingly is independent of noise variance. To evaluate the performance of the proposed filtering algorithm, its mean square error and percentage of preserved edge points were compared with those of traditional adaptive weighted averaging and non-adaptive mean filtering algorithms under different noise variances. Relevant results show that the MAWA filtering algorithm can preserve image structures and edges under motion after attenuating noise, and thus may be used in image sequence filtering.     

GPU实现的椒盐噪声自适应中值滤波算法

提出了一种基于先检测、后滤波的椒盐噪声滤除GPU实现算法。该算法首先依据椒盐噪声的特征,将图像像素分为噪声和信号,然后对噪声像素作标准中值滤波,如果中值为信号,则用中值代替噪声像素灰度值;如果中值为噪声,则取中值邻域,如果中值邻域为信号,则用它代替噪声像素灰度值;否则扩大邻域窗口,重复算法。但随着图像规模的增大,在CPU上执行的时间显著增加。分析并利用图形处理器（GPU）的并行处理特征,并在GPU上实现了本文算法。实验结果表明所提出的算法较经典的自适应中值滤波算法有较好的去噪效果和边缘保护能力,并且随着图像规模的增大,算法执行时间较CPU可以提高最多3个数量级。     

一种基于FIR的自适应滤波器LMS算法设计与实现

本文根据自适应滤波器的原理,对LMS算法进行了讨论。并且在NATLAB环境中实现了一种基于FIR横向结构的自适应滤波器LMS算法,对算法在收敛速度方面进行了分析,并且分析了收敛参数μ取值原则及对算法收敛性能的影响,计算机仿真结果与理论分析相一致。     

An Adaptive Quantization Algorithm for MPEG 2 Video Coding

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自适应改进双直方图均衡算法

文章提出了一种改进双直方图均衡算法,根据图像的熵和输入输出图像的亮度均值差,自适应的选择合适的阈值将图像分割成两个子图,进行均衡处理和灰度均匀化处理,使得输出图像的亮度均值和原图像接近的同时视觉效果达到最好.实验结果证明了该处理方法能取得较好的增强效果.     

用遗传神经网络混合算法求解可变加工时间Job-shop调度问题

有效地混合了遗传算法和基于约束满足的自适应神经网络算法,对于一类加工时间可变的调度问题进行了研究.遗传算法被用来进行迭代寻优.当前代经交叉和变异后生成的染色体对应非可行解,由自适应神经网络运算后得到可行解,对应的染色体作为新一代染色体.本算例的目标函数是基于任务的提前/拖期惩罚、附加惩罚以及加工时间的偏离量惩罚,目标是确定最优加工时间和最优加工顺序极小化目标函数,并与一般的遗传算法相比较,实验结果说明了遗传/自适应神经网络算法混合算法的有效性.     

广义离散随机系统的Kalman滤波的自适应算法

用现代时间序列分析方法,提出一类广义离散随机系统的自适应稳定态KaIman滤波算法,并给出了一个仿真例子．     

数据流频繁项挖掘算法——EC算法

近几年,随着通信、网络等技术的飞速发展,在各个领域经常都会产生大量的信息数据。因此,如何使用有限存储空间进行快速准确地挖掘数据流近似的频繁项成为具有挑战的问题。本文介绍了一种新的挖掘算法——EC算法,使其空间复杂性为O（ε^-1）,每个数据的平均处理时间为O（1）。