基于概念格的分布式约简理论框架

为了缩减知识推理空间,提高分布式环境下知识处理的效率,提出分布式概念格属性约简的理论框架.基于粗糙集理论的思想,从子形式背景和全局形式背景的角度,刻画了核心属性、相对必要属性和绝对不必要属性的属性特征,给出属性约简的判定定理.在此基础上,给出概念格的分布式属性约简方法:首先,使用现有的约简方法分别计算各子形式背景的约简,然后,逐一利用各子背景的约简,通过合并计算得到全局形式背景的约简.给出了算法的实现并用实例验证了它的有效性.分布式约简有效避免了使用现有方法而引起的数据安全和网络通信等问题,提高了约简的计算效率.     

一个描述可视化语言上下文属性化的图文法框架

针对目前已有的上下文相关图文法的描述规范过于复杂或不太直观,提出了一个新的上下文相关图文法的形式框架：上下文属性化的图文法CAGG．该文法将产生式的上下文信息刻画成相关结点的上下文属性来解决嵌入问题．而且进一步分析了合流的CAGG产生式集合的基本特征,并基于此设计了合流产生式集合的判定算法,从而为构造高效的语法分析算法奠定了基础．通过与已有上下文相关图文法的对比分析可知,CAGG图文法的形式更为简洁和直观,因而更适于且更易于应用到可视化语言描述领域．     

一种新的协同过滤推荐算法

协同过滤推荐系统在处理交互性强、需要知识背景的电子商务网站推荐领域,显得力不从心。双信息源模式的协同过滤算法(DISCF)推荐系统通过对稀疏数据集的处理,找到活动用户的相似用户(最近邻居集)和具有知识背景专家集合,结合两个推荐组的建议,形成可靠的信息源,分析各自影响活动用户对目标项目的权重,计算活动用户的最终兴趣度,实现系统推荐。     

集合创新题解读

集合是高中数学的基础知识,在近几年的高考题目中,出现了一类依托集合知识背景设计的创新题型．这些题目形式新颖,对考查同学们的创新能力和对新知识接受能力十分有用．下面给以分类解析．     

对市场营销中产品利益属性的认识及其思考

产品利益属性是指产品本身所固有的性质,是产品在不同领域差异性（不同于其他产品的性质）的集合。也就是说,产品利益属性是产品性质的集合,是产品差异性的集合。决定产品利益属性的因素,由不同领域组成。每个因素在各自领域分别对产品进行性质的规定。产品在每个属性领域所体现出来的性质在产品运作的过程中的作用不同、地位不同、权重不同。呈现在消费者眼前的产品就是这些不同属性交互作用的结果。下面我就产品利益属性的调节作用谈谈观点和看法。     

基于集合覆盖的决策表约简方法及其应用

根据决策表属性约简中保持条件属性对决策属性相对核不变的特点,利用集合覆盖方法,定义了决策表的相关矩阵,把决策表的约简问题转化为求集合覆盖问题,通过求决策表的最小集合覆盖来求出其最小属性约简.同时,给出了基于集合覆盖的决策表属性约简算法,时间复杂度为O(|U|2|C|2),通过应用分析证明了本方法的实用性.     

求解集合问题应注意的几点

一注意集合元素的属性用描述法表示集合的一般形式为:{(?)具有公共属性},其中竖线前面的字母x称为集合的代表元素,在研究集合问题中首先必须弄清集合的代表元素的含义,否则解题时会陷入困境或误入歧途.     

知识的个体属性及其教育意蕴

知识具有个体属性，个体对知识的建构和生成过程千差万别，然而，在我们的知识教育中，“知识”常常是外在于个体的，普遍的，客观的，价值无涉的，知识的丰富内涵及其个体属性不显。为此，在知识教育中，应对知识的个体属性重新给以定位，凸显知识的境域性、默会性和价值关涉，正确认识“掌握知识”，关注知识的个体生成，实现知识教育生活化。     

集合的意义

从小学开始,数学课本上就不断出现过“集合”这个词.例如,有理数的集合;直角三角形的集合;直线上的点的集合等.具有某些共同属性的对象的全体就形成了一个集合.具有某些共同属性的点的全体就形成了一个点的集合(简称点集).许多点集常常是和几何中的基本图形联系在一起的.例如,到一个角的两边距离相等的所有点的集合就是这个角的平分线;到线段的两个端点距离相等的所有点的集合就是这条线段的垂直平分     

教学资源视域下学校知识的公共属性与个体属性

<正>学校知识是专门服务于教师教、学生学的文本化、学科化和体系化知识。它一方面具有公共属性,是人类知识宝库中的重要组成部分,是人类社会共同的精神财富;另一方面具有个体属性,必须被教师和学生个人所获得与掌握,并转化为教师和学生的个体知识。一、知识连续体中的个体知识与公共知识在学校教学中,学校知识的公共属性与个体属性是很难分割的,二者共同构成了知识连续体。教师只有厘清二者的关系,才能发挥其最大效用。     

Compulsory language studies for university degrees: the challenge of decontextualization in language learning

The present paper discusses the decontextualization of learning in a case of compulsory Swedish language studies for university degrees. In this case learning Swedish is mostly disconnected, not only from the everyday lives of the students in a way typical of formal learning in general, but also from the study activities and contexts that students engage in for their major subject. Learning has been transferred to a specific context, the University Language Centre Swedish courses, where the main purpose is to learn Swedish for possible future needs. The study explored the correspondence between Finnish speaking students' own learning goals and the formal objectives set for these compulsory studies (i.e. learning Swedish for educational and occupational purposes). The sample consisted of 10 student groups from different subject majors. The results suggest that all students do not necessarily share the prescribed formal objectives. First of all, students expressed goals which contradicted the formal objectives, namely learning only discrete words or grammar rules. In addition, only four of the 10 groups mentioned learning goals related to their present studies (educational domain) and only five groups discussed learning goals from the point of view of their future professions (occupational domain). The paper discusses ways to overcome the problems of decontextualization in compulsory language studies for university degrees.     

用于改善web搜索的结构化数据抽取技术

为了提高web文本搜索质量,提出了基于语义结构化数据的查询扩展方法.通过分析属性的语义特征（文档频率特征和辨识能力特征）将属性分为概念属性、背景属性和无用属性3类,并且提出了衡量属性语义相关度的标准.设计了trie-bitmap和pair pointer table数据结构来实现发掘属性语义特征和检测属性语义相关度的有效算法.通过使用合适的属性和它们的语义关系,可以为查询关键字生成扩展词并将它们嵌入到具有插值参数的向量空间模型中.实验使用IMDB电影数据库和真实文本数据集来比较所提方法和原始向量空间模型的性能.实验结果证明所提出的查询扩展方法可以有效地提高文本搜索性能,同时属性语义特征和属性语义相关度都具有良好的分类能力.     

Professional practice,learning, and continuing education: an integrated perspective‡

The popular wisdom among professionals is that the knowledge they acquire from practice is far more useful than what they acquire from more formal types of education. This observation contradicts the dominant viewpoint in society and the professional education establishment that has given legitimacy to knowledge that is formal, abstract and general while devaluing knowledge that is local, specific and based in practice. This viewpoint has strongly influenced continuing education, which has followed the model set at the preservice level in focusing on the transmission of formal, abstract knowledge. In this paper, I describe and provide evidence for three propositions that build on the importance of knowledge gained from practice. These are: (1) the goal of professional practice is wise action; (2) knowledge acquired from practice is necessary to achieve this goal; and (3) a model of learning from practice should become the centrepiece of systems of continuing education for the professions.

     

S-粗集理论与知识发现

基于S-粗集,给出了在知识发现中由数据变化获取新知识的方法.应用S-粗集的迁移运算,给出了属性增加时知识的粗糙度减少的结论.     

L’Intégration de Nouvelles Connaissances: Entre Arithmétique et Algèbre

This study analyses students integration of new knowledge in the domain of elementary algebra, which is based on arithmetics, but differs from it in a number of ways. Subjects aged between 11 and 16 years were presented with a task which consisted in evaluating equivalence of either numerical or algebraic isomorphic expressions. The results indicate that the context plays an important role in determining the choice of a strategy of comparison. In evaluating algebric expressions, students use formal rules. The observed errors derive from over-generalisation of prototypical rules and their conditions of application. In the case of numerical expressions, the dominant strategies are re-writing procedures: these may or may not be followed by quantitative evaluations of the resulting expressions. Errors are less frequent, but our analyses show that the semantics of the procedures are not always well understood. In sum, students posses a fair amount of knowledge of various kinds, but this knowledge is not well integrated or interrelated. Hence their knowledge base is not very stable and can easily become deformed.     

The stability of children's mathematical behavior: When is a bug really a bug?

This article describes an empirical investigation of the extent to which incorrect arithmetic algorithms persist over time. The use of subtraction procedures by children aged 9–11 was charted over time periods of 1–3 months. The ways in which several bugs might be related to a single misconception were considered and a set of “bug classes” was identified. The results indicated that the prevailing tendency to attribute stable procedural knowledge and systematic behavior to children of this age is misguided. They provide some insight into the development of mathematical knowledge under the influence of conventional instruction.     

基于属性依赖度的图像隐写分析算法

针对文献[6]将粗糙集属性约简应用于信息隐藏盲检测中检测正确率有所下降的问题,提出了基于属性依赖度的图像隐写分析算法,该算法利用粗糙集理论属性依赖度提出决策表离散优化的措施,寻找一种提高整个决策表分类能力的办法,以达到提高检测正确率的目的。首先利用该算法对决策表进行优化,其次通过属性约简得到最小约简,最后采用支持向量机构造分类器,对Cox、Piva两种不同隐写术进行实验结果表明,使用该算法不仅检测正确率有较大提高,而且检测效率也有较大提高。     

一种基于粗糙集和粒子群优化算法的权重确定方法

为了克服基本粗糙集理论确定权重的不足,提出一种新的基于粗糙集和粒子群优化算法的权重确定方法.该方法先利用粗糙集和粒子群优化算法对决策表进行属性约简,对约简后的决策表再用粗糙集方法计算属性权重.运用该算法对教师职业倦怠与压力数据进行分析,得到影响教师职业倦怠的各种压力因子的权重.研究结果表明,基于粗糙集和粒子群优化算法可以对决策表的权重进行有效的分析.     

Science and Society‐‐a Report on Science Education Activities Organized and Co‐ordinated by the Council of Europe

This study explores the tension between subject knowledge and pedagogic content knowledge in primary teacher education. It documents students and in-service teachers learning about forces within the context of floating and sinking. In doing so it describes not only significant features of the learning process itself but also examines subject specific aspects of learning, identifying some of the inherent difficulties for learners within this domain and demonstrating how learners construct links between tacit knowledge and abstract scientific notions. Implications for teacher education and the teaching of science in the classroom are explored.