基于水平集方法的连续体结构拓扑优化方法研究

采用水平集方法描述结构的拓扑及其变化,使用紧支径向基函数对计算区域的水平集进行插值以得到参数化的水平集方法。针对给定体积约束下结构最小柔度的拓扑优化问题,推导了目标函数对插值系数的灵敏度及拓扑优化的迭代格式,数值计算表明,使用该方法进行结构拓扑优化得到的结果边界形状光滑连续且计算稳定性较好。     

彩色图像的数字水印系统设计

针对数字产品的版权保护问题,利用二维离散整数小波变换的快速性,结合人类视觉系统特性,开发了一种基于彩色图像新的、简单的、鲁棒性盲水印嵌入系统.系统可以将水印信息嵌入到不同整数小波分解级数下的彩色载体图像中去,具有嵌入速度快、安全性高的特点.首先将彩色载体图像由RGB彩色空间转换到YUV空间,再对y分量进行多级整数小波分解,然后分别将有意义的二值图像和字符串作为水印嵌入到不同级数小波分解后的低频域(LLn).算法选择了合适的水印嵌入位置,实验结果证明:系统使图像的不可见性好,所嵌入的水印对一般的图像处理攻击,如噪声、滤波、旋转、压缩等有较强的鲁棒性,系统实用性较强.     

Investigating the relationship between pre-service physics teachers' professional knowledge,self-concept,and interest

This study investigates the relationships between professional knowledge, self-concept, and interest of pre-service physics teachers. In order to support student learning and interest development alike, teachers need a profound professional knowledge and respective motivational orientations. Developing both professional knowledge and motivational orientations in teachers is therefore a key challenge of teacher education. Prior research has focused on the development of content knowledge (CK) and pedagogical content knowledge (PCK) within teacher education, but the role of motivational orientations such as self-concept and interest have mostly been neglected areas of study. As individuals develop domain-specific motivational orientations, they compare their achievement in an external frame to the achievement of their peers, and they compare their achievements in an internal frame across domains. The effects of these psychological processes on domain-specific motivational orientations are described by the generalized internal/external frame of reference model (GI/E model). We assessed the professional knowledge (CK and PCK) and motivational orientations (self-concept and interest) of N = 200 pre-service physics teachers from 12 teacher education institutes in Germany. To investigate the predictions of the GI/E model, we utilized structural equation modeling. In line with the GI/E model, the analysis revealed that pre-service teachers use social comparisons. Pre-service teachers with a higher CK/PCK also showed a higher CK/PCK self-concept. We also identified instances of internal comparisons as we found that a high level of CK corresponds with a lower PCK self-concept. While we could not identify the same effects from professional knowledge on interest, self-concept mediated the effects from professional knowledge on interest. The results suggest that interdependencies between professional knowledge and motivational orientation should be given more consideration in teacher education research and should also be addressed more explicitly in teacher education.     

Unpacking teachers’ intentions to integrate technology: A meta-analysis

The Technology Acceptance Model (TAM) is a key model describing teachers' intentions to use technology. This meta-analysis clarifies some of the contradictory findings surrounding the relations within the TAM for a sample of 45 studies comprising 300 correlations. We evaluate the overall fit of the TAM and its structural parameters, and quantify the between-sample variation through meta-analytic structural equation modeling. The TAM fitted the data well, and all structural parameters were statistically significant. On average, the TAM variables explained 39.2% of the variance in teachers' intentions to use technology. Several sample, measurement, and publication characteristics, including teachers’ experience and the representation of the TAM variables, moderated the relations within the TAM. Overall, the TAM represents a valid model explaining technology acceptance—however, the degree of explanation and the relative importance of predictors vary across samples. Implications for further research, in particular the generalizability of the TAM, are discussed.     

马克思再生产模型中的最高、最低积累率

马克思的两部类再生产模型中的各部类和全社会最高与最低积累率问题,是尚未获得完满解决的难点问题。本文运用单调函数的性质和求函数最大、最小值方法,通过解析,给出了静态意义下的各部类和全社会最高及最低积累率与两个部类结构参数的函数关系式。并且引用和借鉴《资本论》中的举例,对给出的函数关系式做了算例验证。     

女画家潘玉良的双重色彩

画家潘玉良是20世纪初我国第一代远赴西方国家学习西洋画的杰出女性.她毕生研究融合中西绘画艺术,并在国际画坛上取得辉煌的成绩.她的成长带有传奇的色彩,从最初的雏妓到留学的教授,伴随她一生的是苦难历程,造成她心理上的孤独、忧郁及缺失性的体验.结合她带有忧郁情感的作品,分析其在绘画艺术上所获得的成就,并深入了解其产生忧郁情感...     

浅谈色彩教学

色彩教学的目的在于通过丰富的色彩语言表现物体和再现物体。我国的传统美术教学主要以传授系统的知识和技能为主,缺乏个性的展示。因此,目前的美术教育提倡"个性化教育"成为改革的重要趋势。美术教学可以从色彩出发,结合学生的情感和个性特点进行教学。不但提高了学生们对色彩的认识以及运用水平,又可以丰富学生的情感和个性。     

经营巧妙 创造个性——谈旅游工艺品设计

不同地区特殊的文化积淀、自然环境和地理位置等因素是特色旅游工艺品存在的重要条件。工艺师设计旅游工艺品时应把握一个＂巧＂字,即材巧、形巧、色巧、技巧,从而设计出工艺独特、加工手段精湛的工艺品。     

波普艺术风格在时装色彩图案上的应用探讨

波普艺术风格是西方20世纪五六十年代艺术趋向的产物,对时装设计的风格方向产生引领作用,它帮助人们解开时尚的密码,诠释21世纪的着装符号。波普艺术风格在时装设计上的应用无所不在,主要从色彩图案等构成要素的应用上进行探讨和说明,力争把握其精神实质,将艺术理论转化为实践,同时结合近年时装市场行情,有效地将波普艺术转化为时装设计的创新动力,努力探索时装设计的新形式、新途径。     

“文学的大饼”与重庆的烧饼——也读《经典关系》

重庆实力派作家莫怀戚的长篇小说《经典关系》,体现出具有某种地方色彩的当代长篇小说,在创作上的可能性与可行性,尤其是面对有关＂男女关系＂在重庆城市发展过程中的现实演变,如何运用重庆方言来进行小说叙事,在呈现出个人写作的成功与局限的同时,进行了具有再创性质的个人示范。