Teaching materials to enhance the visual expression of Web pages for students not in art or design majors

The explosive growth of the Internet has made the knowledge and skills for creating Web pages into general subjects that all students should learn. It is now common to teach the technical side of the production of Web pages and many teaching materials have been developed. However teaching the aesthetic side of Web page design has been neglected, and students not in art or design majors are normally confronted with difficulties when they do expressive design of Web pages.     

Characterising effective eLearning resources

The widespread availability of digital learning resources in a variety of media formats offers the possibility to make a profound difference in education. This potential has not been fully realised for range of interrelated reasons. In this paper we study the key characteristics of learning resources that have proved effective in changing learning and teaching, and relate them to existing frameworks for understanding resources. We outline the relationships between resources, their users, and the way they are used, and explore issues that influence practitioners in choosing a particular resource. Our study is based on a review of resources for e-learning and chemistry in post-compulsory education, undertaken for the UK Joint Information Systems Committees (JISC), as part of a wider study examining ‘The Effectiveness of Resources, Tools and Support Services used by Tutors in Designing and Delivering E-Learning Activities’.     

基于有向面积的角点分类算法

在3维场景重构、运动估计、机器视觉等领域,不仅希望能检测出图像中的角点,而且还希望获得角点附近更多的信息,即能对角点进行进一步分类。为了能对图像中检测出的角点进行分类,提出了一种基于有向面积的角点分类方法,该方法首先采用基于协方差矩阵特征向量的小波变换角点检测原理检测出图像边缘上的角点;然后根据角点两侧的边缘信息定义了6种类型的角点;最后通过计算角点附近边缘上顺序排列的3个有向面积,实现对角点的分类。实验表明,基于有向面积的角点分类,具有较高的准确性。     

水资源缺乏地区地表水环境承载现状研究——以京津冀和西北五省(自治区)为例

本研究以主体功能区划作为控制单元进行划分,以水功能区纳污能力作为环境容量基础数据,结合国家环境保护部污染物排放统计数据,分析京津冀和西北五省(自治区)的不同主体功能区的地表水环境容量超载情况。结果显示,在水资源缺乏的京津冀和西北五省(自治区)地区,其重点开发区的氨氮排放入河量均已超出水环境容量,城镇生活污水排放是水环境氨氮容量超载的主要贡献因子。对于农产品主产区和重点生态功能区,京津冀地区水环境的化学需氧量(COD)和氨氮排放量普遍超载,而西北五省(自治区)还有19%~73%的水环境容量剩余。不同主体功能区的环境和产业政策取决于主体功能区的类型和水环境容量的超载情况。     

高强钢20MnTiB多工位冷镦变形行为EI北大核心CSCD

通过对高强螺栓多工位冷镦变形分区的金属流动、显微组织、力学性能及其变化规律进行分析,并采用Deform-3D数值模拟和实际产品成形相结合的方法,来研究高强材料的多工位冷镦变形行为。结果表明:多工位冷镦变形属于低动态变形;大、小变形区的宏观流线和显微组织有明显的"遗留性",而难变形区由于高强材料的"包辛格效应",铁素体由拉长的晶粒变成等轴晶粒,而珠光体的带状消失,组织"遗留性"最差;通过低动态多工位冷镦变形,20MnTiB高强钢微观组织中铁素体和珠光体均发生了形变强化,且硬度值的增幅相近。     

基于FFT-OMP-DAMAS波束形成方法的汽车前围板隔声薄弱部位识别

为实现汽车前围板隔声薄弱部位的准确识别,文章提出了基于快速傅里叶变换(Fast Fourier Transform,FFT)和正交匹配追踪(Orthogonal Matching Pursuit,OMP)的反卷积(Deconvolution Approach for the Mapping of Acoustic Sourc‐es,DAMAS)波束形成方法(FFT-OMP-DAMAS)。该方法基于声源稀疏分布假设,利用正交匹配追踪思想求解反卷积问题,并进一步结合傅里叶变换和点扩散函数空间转移不变假设降低计算维度。在混响室-消声室内,分别利用延迟求和方法,DAMAS方法和FFT-OMP-DAMAS方法进行了某汽车前围板隔声薄弱部位识别试验,结果表明：FFTOMP-DAMAS方法能够有效抑制旁瓣和伪源,有效缩减主瓣宽度,从而准确识别汽车前围板隔声薄弱部位,且相较于传统的DAMAS方法,文中提出的FFT-OMP-DAMAS方法能获得更清晰的成像结果,计算效率有了明显提高。     

在城市化进程中漫谈城建与环境问题

本文从介绍“自然回归论”和“城市化威胁论”引述到重视解决好城市化进程中出现的环境问题的重要性及其所涉及的方方面面的问题。     

Soil moisture estimation over vegetated terrains using multitemporal remote sensing data

A new method for retrieving soil moisture content over vegetated fields, employing multitemporal radar and optical images, is presented. It is based on the integration of the temporal series of radar data within an inversion scheme and on the correction of the vegetation effects. The retrieval algorithm uses the Bayesian maximum posterior probability and assumes the existence of a relation among the soil conditions at the different times of the series. The correction of the vegetation effects models the variation, with respect to the initial time of the series, of the component of the backscattering coefficient due to the soil characteristics as function of the variations of the measured backscattering coefficient and of the biomass. The method is tested on the data acquired throughout the SMEX02 experiment. The results show that measured and estimated soil moistures are fairly well correlated and that the performances of multitemporal retrieval algorithm are better than those obtained by employing one radar acquisition, especially in terms of capability to detect soil moisture changes. Although the approach to correct the vegetation effects on radar observations needs to be further assessed on different sets of data, this finding demonstrates that the proposed method has a potential to improve the quality of the soil moisture retrievals.     

Inducing attitude change toward online gaming among adolescent players based on dissonance theory: The role of threats and justification of effort

The negative impact of online gaming on adolescents has received much attention. The question of how to reduce their pathological use of online gaming is a critical issue. Based on the concept of external justification in dissonance theory, this experimental study aimed to examine whether severity of threat and justification of effort would impact adolescent players’ attitude change toward online gaming and their subjective estimations of online gaming addiction. The results echoed predictions from classic studies in dissonance theory. When participants engaged in attitude–discrepant behavior, i.e., persuading other adolescents that an apparently interesting online game is not fun at all, their attitudes toward online gaming shifted more dramatically to the negative side in the context of a low level of threat rather than a high level of threat. Additionally, the magnitude of attitude change was more prominent when participants exerted more rather than less effort to engage in attitude–discrepant behavior. Moreover, a similar pattern of participants’ evaluations of the likelihood of online gaming addiction was also observed. The findings show that dissonance theory has the potential to be useful for inducing adolescent players to disengage in online gaming.     

Effects of attitudes and behaviours on learning mathematics with computer tools

This mixed-methods study investigates the effects of student attitudes and behaviours on the outcomes of learning mathematics with computer tools. A computer tool was used to help students develop the mathematical concept of function. In the whole sample (N = 521), student attitudes could account for a 3.4 point difference in test scores between individuals on a 10-point scale. General attitude towards mathematics positively predicted test scores. However, more able students who were well-disposed towards mathematical computer tools achieved lower scores. Self-reported behaviours were unrelated to test scores. Detailed observation of a small number of students (N = 8) revealed that positive attitudes towards mathematics and mathematical computer tools augmented exhibited learning behaviours, and that both a positive attitude to mathematical computer tools and exhibited learning behaviours benefited tool mastery. Although tool mastery and test scores are intimately related, reflective processes appear to mediate this relationship. Promoting learning with mathematical computer tools needs to take several factors into account, including improving student attitudes, raising levels of learning behaviours, and giving sufficient opportunity for constructing new mathematical knowledge within meaningful mathematical discourse.