体育用品制造业固定资产投资规模的灰色动态模型探索

以耐克公司为例,详细介绍了运用灰色五步建模理论,判断体育用品制造业固定资产投资规模的动态量化分析方法,为现代体育用品制造业经营管理的科学决策提供了一种便捷、实效的数学工具。     

学生学校适应性影响因素的多层线性分析

问卷调查安徽省53所学校校长、4 010名初三学生,运用两水平多层线性模型,探查影响学生学校适应性的因素。研究发现:(1)学生学校适应性校际差别不大。(2)在学生个体层面,兄弟姐妹数量越少、家长学习期望越大、家长学习参与越多、个体知觉的同学关系与师生关系越积极,学生学校适应性就越好。(3)在学校层面,未发现有影响学生学校适应性的因素。     

从细节谈数学建模竞赛

结合对数学建模的实践,总结借鉴专家学者的经验,着眼于细节,分析参赛者容易出现的一些问题,并以2011年本科B题为例,从组队和培训、指导教师的任务、竞赛流程、建模中的注意事项、对学习和科研的意义几个方面,介绍提高团队交流合作、模型建立及计算、提高教师和学生的科研能力等经验和建议。     

Preservice Elementary Teachers' Evaluations of Elementary Students' Scientific Models: An aspect of pedagogical content knowledge for scientific modeling

Part of the work of teaching elementary science involves evaluating elementary students' work. Depending on the nature of the student work, this task can be straightforward. However, evaluating elementary students' representations of their science learning in the form of scientific models can pose significant challenges for elementary teachers. To address some of these challenges, we incorporated a modeling-based elementary science unit in our elementary science teaching methods course to support preservice teachers in gaining knowledge about and experience in evaluating students' scientific models. In this study, we investigate the approaches and criteria preservice elementary teachers use to evaluate elementary student-generated scientific models. Our findings suggest that with instruction, preservice elementary teachers can adopt criterion-based approaches to evaluating students' scientific models. Additionally, preservice teachers make gains in their self-efficacy for evaluating elementary students' scientific models. Taken together, these findings indicate that preservice teachers can begin to develop aspects of pedagogical content knowledge for scientific modeling.     

Exploring Third-Grade Student Model-Based Explanations about Plant Relationships within an Ecosystem

Elementary students should have opportunities to develop scientific models to reason and build understanding about how and why plants depend on relationships within an ecosystem for growth and survival. However, scientific modeling practices are rarely included within elementary science learning environments and disciplinary content is often treated as discrete pieces separate from scientific practice. Elementary students have few, if any, opportunities to reason about how individual organisms, such as plants, hold critical relationships with their surrounding environment. The purpose of this design-based research study is to build a learning performance to identify and explore the third-grade students’ baseline understanding of and their reasoning about plant–ecosystem relationships when engaged in the practices of modeling. The developed learning performance integrated scientific content and core scientific activity to identify and measure how students build knowledge about the role of plants in ecosystems through the practices of modeling. Our findings indicate that the third-grade students’ ideas about plant growth include abiotic and biotic relationships. Further, they used their models to reason about how and why these relationships were necessary to maintain plant stasis. However, while the majority of the third-grade students were able to identify and reason about plant–abiotic relationships, a much smaller group reasoned about plant–abiotic–animal relationships. Implications from the study suggest that modeling serves as a tool to support elementary students in reasoning about system relationships, but they require greater curricular and instructional support in conceptualizing how and why ecosystem relationships are necessary for plant growth and development.     

Modeling pollutant transport in overland flow over non-planar and non-homogenous infiltrating surfaces

Pollutant transport in overland flow over surfaces with spatially varying microtopography,roughness,and infiltration was investigated using the diffusion wave equation and transport rate-based equation.The finite volume method in space and an implicit backward difference scheme in time were employed in the numerical solution of the 2D governing equations.The developed model was first tested against an analytical solution and an experimental study involving overland flow and the associated pollutant transport,subsequently a series of numerical tests were carried out.Non-point source pollution was investigated under spatially varying microtopography,roughness,and infiltration.The simulation results showed that microtopography and roughness were the dominant factors causing significant spatial variations in solute concentration.When the spatially varying microtopography was replaced by a smooth surface,the result was an overestimation of the solute rate at the outlet of the upland.On the other hand,when the spatially varying roughness was replaced by the average roughness and spatially varying infiltration rate by the average infiltration rate,the pollutant discharge at the outlet of the upland was not significantly affected.The numerical results further showed that one cannot ignore the spatial variations of slope and roughness when investigating the local pollutant concentration distribution.     

一项基于知识建模的课程分析个案研究

基于知识建模的课程分析技术是一种精细分析技术,它可以用于课程的内在一致性分析研究。文章采用知识建模以及剪枝技术,对某大学教育技术学专业的5门专业核心课程进行了个案研究。研究表明,这些课程在课程本体与课程目标之间存在着严重的不一致,课程体系内部也存在着学科中心、拼接严重、内容大量重复的问题。但是要彻底解决这些问题,必须以教育技术学学科自身知识的丰富储备为前提。这再次表明,教育技术学学科建设的核心工作是知识的创生,不是做项目。     

数学建模竞赛模式对教改的启示

数学理论知识是很多课程的基础,在实际工作领域中也有广泛的应用,而理工科大学生在抽象数学学习中常存在学习容易倦怠的情况。数学建模竞赛有助于提高学生的学习积极性和效率,提升教师的教学和科研水平,应在教学中进行更大范围的推广。文章在具体分析数学建模竞赛对师生教与学的促进作用的基础上,探讨了推广数学建模竞赛的方式。     

攻击模型BBFPAN分层的新方法

针对以模糊Petri网为理论基础的网络攻击模型BBFPAN自学习能力差的缺点,提出了一种新的适用于对攻击模型BBFPAN进行层次式划分的分层算法,为将神经网络理论引入攻击模型的研究奠定了基础。