High-School Students' Attitudes Regarding Procedural Abstraction

During the last decade a new computer science curriculum has been taught in Israeli high schools. This curriculum introduces CS concepts and problem-solving methods independently of specific computers and programming languages, along with the practical implementation of those concepts and methods encountered in actual programming languages. The advanced study unit of the curriculum, Software Design, introduces the students to various aspects of software systems design through the use of abstract data types (ADTs). One main goal of the unit is to develop abstract thinking skills and problem-solving abilities. More specifically, the unit presents principles such as procedural abstraction, data abstraction, information hiding, modularity, efficiency, and reuse of code.We present the results of a preliminary study whose aim was to assess students' attitudes regarding procedural abstraction. The research population consisted of high-school students who attended the Software Design course (beginners), and a control group of undergraduate CS students (advanced). The results of the study clearly indicated a significant difference between the attitudes of the two groups. We found that the advanced students preferred algorithms that were formulated to some extent with high-level abstraction; however, they encountered a cognitive barrier when dealing with algorithms that they had evaluated as too abstract for them. However, beginners felt more comfortable with algorithms with low-level abstraction. Nevertheless they showed open-mindedness toward some degree of procedural abstraction. The results of the study were used to design scaffolding problem-solving tools for algorithm development, utilizing procedural abstraction techniques that can be adapted to various student populations (Haberman, B. (2002) SIGCSE Bulletin, 34(4), 60–64).     

教师教学生活研究引论

关注教师教学生活是改善教师生存状况的迫切需要,也是基础教育课程改革的必然要求,还是教师专业发展的内在逻辑。教师教学生活研究有着特定的内容和范畴,在研究过程中应遵循理论研究与实证研究相统一原则、主位研究与客位研究相结合原则、本土化原则、多样化原则。     

从语用角度看语篇的隐性连贯

语篇连贯分为显性连贯和隐性连贯,显性连贯具有语篇形式上的体现,而隐性连贯的解释依赖于语用含义。Austin的“言语行为(speechact)”、Grice的“合作原则(cooperativeprinciple)”和语境(context)的相关理论等均从不同的视角揭示了语篇隐性连贯的实质。     

行政回避制度若干理论问题研究

行政回避制度是行政程序法上的基本制度。行政回避发生在行政程序中，与公务员回避、司法回避有一定的区别。行政回避制度根源于英国的自然正义原则及美国的程序公正原则。在行政程序法中，目标模式、基本原则、基本制度是密切联系的，由此，行政回避制度的逻辑起点在于人们对程序正义的期待。     

对Cluster模型的几点质疑

本文证明Cluster模型违背了细致平衡原理,指出了海中核子pick-up图象的不合理性。该模型的发射几率中不考虑复杂粒子正确构成的影响更是一个显著的倒退。     

圆周上的范德瓦尔登数

The big upper bound of typical van der Waerden number was investigated through calculating the van der Waerden number on a circle. And the van der Waerden number Wh (3,3) = 9, Wh (3,3,3)≥25 on a circle was calculated by computer.     

大学本质和科学办学

大学本质是一种功能独特的文化机构,科学办学是对大学办学的基本要求,两者互相联系。大学理念是人们对大学的本质及其办学规律的哲学思考,是大学科学办学的理论基础,其核心问题包括大学的责任观、大学的本质观、大学的办学观和大学的价值观。     

端头支护的研究与应用

介绍了原吊环穿管临时支护的缺点及手摇申缩式端头临时支护的特点，工作原理及应用中的优点。     

A hybrid generative/discriminative approach to text classification with additional information

This paper presents a classifier for text data samples consisting of main text and additional components, such as Web pages and technical papers. We focus on multiclass and single-labeled text classification problems and design the classifier based on a hybrid composed of probabilistic generative and discriminative approaches. Our formulation considers individual component generative models and constructs the classifier by combining these trained models based on the maximum entropy principle. We use naive Bayes models as the component generative models for the main text and additional components such as titles, links, and authors, so that we can apply our formulation to document and Web page classification problems. Our experimental results for four test collections confirmed that our hybrid approach effectively combined main text and additional components and thus improved classification performance.     

弹性函数的几何机理

弹性函数是研究当自变量有微弱变化时,函数的相对变化率。文章构造一条初始弹性直线,从几何的角度分析,弹性函数就是函数的切线斜率与初始弹性直线斜率之比;也是函数在弹性支点的微分与初始弹性直线在弹性支点的增量之比。在修订参考文献的基础上,着重对几何机理进行分析。