Mathematical Modeling in the Primary School: Children's Construction of a Consumer Guide

This paper examines 6th grade children's local conceptual development and mathematization processes as they worked a comprehensive mathematical modeling problem (creating a consumer guide for deciding the best snack chip) over several class periods. The children and their teachers were participating in a 3-year longitudinal teaching experiment in which sequences of mathematical modeling problems were implemented from the 5th grade (10 years of age) though to the 7th grade. In contrast to traditional problem solving, mathematical modeling requires children to generate and develop their own mathematical ideas and processes, and to form systems of relationships that are generalizable and reusable. Reported here is a detailed analysis of the iterative cycles of development of one group of children as they worked the problem, followed by a summary of the mathematization processes displayed by all groups. Children's critical reflections on their models are also reported. The results show how children can independently develop constructs and processes through meaningful problem solving. Children's development included creating systems for operationally defining constructs; selecting, categorizing, and ranking factors; quantifying quantitative and qualitative data; and transforming quantities.     

风险认知与决策领域的研究现状分析

风险决策是指决策者在面临两个或两个以上不确定的决策后果,尤其是在面对伴有负面结果的可能性时,所产生的复杂心理过程.对个体风险知觉的探究主要包括风险认知与风险偏好两个方面.风险决策常常涉及多个不确定性的负面结果.因此,个体所知觉到的风险情景也不会是单一的,对动态决策模型的研究成为决策科学发展的一个重要方向.     

对完善我国个人所得税的思考

我国目前的个人所得税占财政收入与税收总收入的比重过低，直接影响了财政收入职能的实现。个人所得税必须从税制模式的选择和征管制度的实施上加以完善。     

人类学方法在外语教学中的应用

人类学研究的出发点是调查，它要求外语教学要进行系统的、长期的、实地的考察，对两种不同化情景进行细致的比较分析，然后概括出实实在在的理论，以指导我们的外语教学。     

水口电厂电能计量管理系统中的数据采集

数据采集系统中,系统的稳定性及快速性是两个重要的因素.以水口电厂电能计量管理系统中的数据采集为例,来分析如何用工控机配上Com口扩展卡,采集多块MK3电能表上的数据以提高系统的稳定性及提高数据采集的速度.     

Rate Control for MPEG-4 Bit Stream

Totransmitthemultimediadataovertheinternet ,pre encodedvideobitstreamsarepreferablebecauseofthelimitofthenetworkbandwidth .Inmostcases ,theencodershouldknowthechannelcharacteristicsinad vanceandencodethemasparameters .Consequently ,theflexibilityisreduced .Theratecontrolisemployedtocontroltheoutputbitrateaccordingtonetworkcondi tions.Forwirelessnetworks ,theirbandwidthsaremuchmorelimitedthanwirenetworks.Soratecontrolbecomesespeciallyimportantfortransmittingmultimediaoverthewirelessdomains[1- …     

用Javabean构建数据过滤的Script代码生成器

针对asp或jsp的客户端数据过滤程序代码由手工编写,编程效率低的缺点,提出了用脚本代码生成器实现自动生成数据过滤代码的方法。生成器的主要组件是Javabean,它可以连接到不同的数据库并操作数据表,在提取数据表的字段结构信息后,由用户选择需要过滤的字段,生成器能根据数据表的结构参数匹配bean中的相关过滤函数,最后生成具有数据过滤能力的客户端脚本代码文档。将生成器用于Web程序的开发,不仅能减少开发人员在编写、测试和修改代码工作量,而且能及时跟踪数据库(表)设计的改变,脚本代码生成高效、自动、准确。     

Statistical Power of the Multiple Domain Latent Growth Model for Detecting Group Differences

The latent growth model (LGM) in structural equation modeling (SEM) may be extended to allow for the modeling of associations among multiple latent growth trajectories, resulting in a multiple domain latent growth model (MDLGM). While the MDLGM is conceived as a more powerful multivariate analysis technique, the examination of its methodological performance is very limited. Hence, the present study compared the power of the MDLGM with that of a set of univariate LGMs for detecting group differences in growth rates over time using a Monte Carlo study with a two-group and two-domain design. The results indicated that there were different scenarios where the power rates for the MDLGM were greater than that of the set of LGMs (and vice versa) due to a joint function of the two domains’ intercorrelation size and the group difference effect size.     

小说社会学研究的理论范式及其转换空间

在20世纪文学批评领域内，小说社会学研究的理论模式与批评范式在历史与审美的交融中，逐步由“外在批评”转向与“内在研究”的结合。其中，戈德曼的“发生学结构主义”文学社会学理论、深入研究文本结构要素与特定社会精神结构三者间的复杂关系，生成了独特的批评视角。由此，运用“社会学的想像力”，将“发生学结构主义”文学研究方法在中国小说文本研究中加以转换，便可探讨社会学方法与其他方法结合的可能性，拓展小说社会学领域广阔的再生空间。     

塑料异型材挤出成型模具建模和仿真技术

阐述了塑料异型材挤出成型模具在设计与制造中的建模和仿真的基本方法,指出产品开发过程及塑料挤出成型模具的仿真和虚拟样机及虚拟制造技术是加快开发塑料挤出成型新产品步伐的必由之路.