Adding up or Down: A Discussion     

《The Journal of educational research》2012,105(4):251-261

ABSTRACT

Increased access to algebra was a focal point of the National Mathematics Advisory Panel's 2008 report on improving mathematics learning in the United States. Past research found positive effects for early access to algebra, but the focus on average effects may mask important variation across student subgroups. The author addresses whether these positive effects hold up when the analysis is expanded to examine effect heterogeneity. Using a nationally representative sample of eighth-grade students in 1988, the author examined sensitivity of findings to methods for selection bias adjustment, heterogeneity across the propensity to take algebra in Grade 8, and across schools. The findings support past research regarding positive benefits to Grade 8 algebra and are consistent with policies that increase access to algebra in middle school.  相似文献   

美国对华反补贴调查中的专向性标准评析     

张书林 《韩山师范学院学报》2012,(5):45-49

《SCM协定》中的专向性标准可以说是美国法中的专向性标准的编纂和修改,但又有相当的丰富和发展。虽然美国1994年《乌拉圭回合协定法》对《SCM协定》作出了一定的回应,但就专向性标准而言,二者还是有不一致的地方。审视美国对华反补贴调查中的专向性标准,有值得商榷的地方,也有明显违背《SCM协定》的做法,中国政府可以根据个案的具体情况针对性地进行抗辩。在宏观层面,中国政府在经济立法和政策制定上应该未雨绸缪;在专向性国际规则的形成和发展过程中应发挥积极作用,促进更加公平合理的专向性标准的确立。  相似文献   

英语语篇会话含义及其语用推理模式构建研究     

吴艳 《淮南师范学院学报》2012,14(4):69-73

会话含义及其推理模式在语用学研究中具有较强的操作性。对英语语篇中会话含义及其推理模式构建分析与研究表明：新格莱斯与古典格莱斯会话含义理论下的语用推理模式除具有共同点外,还具有一定的区别,这一发现不仅可以使语用学进一步揭示日常语言运用的一般规律,还可以增强英语语言学习者的语篇能力。  相似文献   

Predicting crest settlement in concrete face rockfill dams using adaptive neuro-fuzzy inference system and gene expression programming intelligent methods     

Danial BEHNIA  Kaveh AHANGARI  Ali NOORZAD  Sayed Rahim MOEINOSSADAT 《浙江大学学报(A卷英文版)》2013,14(8):589-602

This paper deals with the estimation of crest settlement in a concrete face rockfill dam （CFRD）, utilizing intelligent methods. Following completion of dam construction, considerable movements of the crest and the body of the dam can develop during the first impoundment of the reservoir. Although there is vast experience worldwide in CFRD design and construction, few accurate experimental relationships are available to predict the settlement in CFRD. The goal is to advance the development of intelligent methods to estimate the subsidence of dams at the design stage. Due to dam zonifieation and uncertainties in material properties, these methods appear to be the appropriate choice. In this study, the crest settlement behavior of CFRDs is analyzed based on compiled data of 24 CFRDs constructed during recent years around the world, along with the utilization of gene ex- pression programming （GEP） and adaptive neuro-fuzzy inference system （ANFIS） methods. In addition, dam height （H）, shape factor （St）, and time （t, time after first operation） are also assessed, being considered major factors in predicting the settlement behavior. From the relationships proposed, the values ofR2 for both equations of GEP （with and without constant） were 0.9603 and 0.9734, and for the three approaches of ANFIS （grid partitioning （GP）, subtractive clustering method （SCM）, and fuzzy c-means clustering （FCM）） were 0.9693, 0.8657, and 0.8848, respectively. The obtained results indicate that the overall behavior evaluated by this approach is consistent with the measured data of other CFRDs.  相似文献   

Causal Inferences in the Campbellian Validity System     

Thorleif Lund 《Scandinavian Journal of Educational Research》2013,57(3):205-220

The purpose of the present paper is to critically examine causal inferences and internal validity as defined by Campbell and co‐workers. Several arguments are given against their counterfactual effect definition, and this effect definition should be considered inadequate for causal research in general. Moreover, their defined independence between internal and construct validity is not meaningful. An alternative causal inference and its validity are proposed, where the causal effect is defined in factual terms, and where the causal inference includes constructs.  相似文献   

Belief,Doubt and Reason: C. S. Peirce on education     

《Educational Philosophy and Theory》2013,45(2):177-189

In this paper, we explore Peirce's work for insights into a theory of learning and cognition for education. Our focus for this exploration is Peirce's paper The Fixation of Belief (FOB), originally published in 1877 in Popular Science Monthly. We begin by examining Peirce's assertion that the study of logic is essential for understanding thought and reasoning. We explicate Peirce's view of the nature of reasoning itself—the characteristic guiding principles or ‘habits of mind’ that underlie acts of inference, the dimensions of and interaction between doubt and belief, and his four methods of resolving or ‘fixing’ belief (i.e., tenacity, authority, a priori, and experimentation). The four methods are then juxtaposed against current models of teaching and learning such as constructivism, schema theory, situated cognition, and inquiry learning. Finally, we discuss Peirce's modes of inference as they relate educationally to the resolution of doubt and beliefs and offer an example of belief resolution from an experienced teacher in a professional development environment.  相似文献   

细胞信号转导网络模型简化的一种混合推理方法     

贾建芳  刘太元  岳红王宏 《中国科学院大学学报》2008,25(3):355-366

细胞信号转导网络的结构复杂,规模庞大,建立的数学模型维数高,变量多,具有高度非线性。在复杂系统分析设计中,模型简化始终是主要的研究问题之一。提出一种基于混合推理方法的模型简化策略,利用代谢控制分析、敏感性分析、主元分析和通量分析相结合,降低系统模型维数,减少生化反应个数,简化系统结构。以NF-κB信号转导网络作为研究对象,原模型由24个常微分方程和64个参数组成,简化模型则包括17个常微分方程,1个代数方程和52个参数。仿真结果表明,简化模型能够准确地预测系统的动态特性,为模型分析和参数辨识提供方便,验证了模型简化策略的有效性。  相似文献   

围绕数学素质进行基本技能训练—中学生运算推理技能测试结果透视   总被引：2，自引：0，他引：2  

田中  徐龙炳 《数学教育学报》2000,9(1):33-38

对数学素质教育界定的理论进行了比较分析,在此基础上阐明了自己的观点,并以近期在苏南四地区所作的中学生运算、推理技能测试结果为分析材料,从一个侧面阐述了对数学素质教育的一些看法．  相似文献   

认知逻辑——对休谟问题的一种解决方案     

熊立文 《中山大学学报论丛》2000,(2)

休谟认为人的归纳认识过程不是一个逻辑推理的过程,而是一个习惯心理过程。罗素为解决休谟问题而提出归纳原则。金岳霖等人力图证明归纳原则是永真命题,但未对可能命题作出语义解释。该文用欣迪卡的认知逻辑理论及其模型集语义刻画归纳推理,证明罗素的归纳原则在这种逻辑中是有效的。我们还得到另一个有趣的结果。  相似文献   

从人工智能看当代逻辑学的发展   总被引：9，自引：0，他引：9  

陈波 《中山大学学报论丛》2000,(2)

文章认为,计算机科学和人工智能将是21世纪逻辑学发展的主要动力源泉,并且在很大程度上将决定21世纪逻辑学的面貌。至少在21世纪早期,逻辑学将重点关注下列论题:(1)如何在逻辑中处理常识推理的弗协调、非单调和容错性因素;(2)如何使机器人具有人的创造性智能,如从经验证据中建立用于指导以后行动的可错的归纳判断;(3)如何进行知识表示和知识推理,特别是基于已有的知识库以及各认知主体相互之间的知识而进行的推理;(4)如何结合各种语境因素进行自然语言理解和推理,使智能机器人能够用人的自然语言与人进行成功的交际等等。  相似文献