A Study of Sensori-Motor and Conceptual Thinking in Children between the Ages of Nine and Eighteen

In this research, the author addresses whether the application of unidimensional item response models provides valid interpretation of test results when administering items sensitive to multiple latent dimensions. Overall, the present study found that unidimensional models are quite robust to the violation of the unidimensionality assumption due to secondary dimensions from sensitive items. When secondary dimensions are highly correlated with main construct, unidimensional models generally fit and the accuracy of ability estimation is comparable to that of strictly unidimensional tests. In addition, longer tests are more robust to the violation of the essential unidimensionality assumption than shorter ones. The author also shows that unidimensional item response theory models estimate item difficulty parameter better than item discrimination parameter in tests with secondary dimensions.     

An Analysis of Some New Statistical Methods for Selecting Test Items

In this study, the relationship between student affective performance and classroom physical environment, social climate, and management style were investigated in a sample of classes in Hong Kong primary schools. The results of Pearson and canonical correlation analyses indicated that among the measures of classroom environment, perceived quality of physical environment and class master's expert power, personal power, and coercive power were the strongest predictors of affective performance. This finding supports the importance of class master's management style in the classroom environment. Students' attitudes toward school and teachers appeared to be most sensitive to variation in the classroom environment, and self-concept was the least sensitive among the seven student affective measures. Students' self-efficacy of learning and intention to drop out were moderately sensitive to classroom environment. Profiles of effective and ineffective classroom environments were also mapped. In effective classrooms, class masters care for students, pay attention to teaching, do not use force or punishment but do create a good classroom climate with their professional knowledge, personal morality, and personality. Physical environment and psychological environment are both important; a good classroom environment is highly correlated with student affective performance.     

一种用于图像序列斑点去除的运动估计修正方法

在数字视频处理中经常需要考虑斑点去除问题。运动矢量估计是斑点检测和去除的基本步骤。在斑点存在的区域,运动向量的估计可能会出现较大的偏差。大多数算法只通过空间上运动矢量的相关性来进行修正。本文根据空间上和时间上图像灰度和运动矢量相关的特点,并考虑块分级之间运动矢量的相关性,提出了一种运动估计的修正方法。仿真结果显示,本文的方法是有效的。     

一类广义隐马尔科夫模型的建模与参数估计(英文)

隐马尔科夫模型在很多方面已有广泛应用.讨论了一类更为一般的模型,这类模型由WojciechPieczynski首次提出,并且给出了在图像识别中的应用.这里首次给出在离散观测和离散状态下该模型的精确数学描述,其中包括建模、状态估计和参数估计,这些算法都是首次被提出的     

用户界面评估策略探析

计算机应用领域不断扩大,用户成份发生了诸多变化,应用系统呈现出更强的交互性。若没有一个与用户能力和特点相适应并能与计算机快速进行有效通信的用户界面,软、硬件发展带来的计算机处理速度和性能的提高,并不能变成用户工作的高效率,相反可能导致工作效率降低。因此对界面设计提出了更高的要求,自然用户界面评估策略是界面设计中一个不容忽视的问题了。     

黄陵庙水文站流量误差试验研究

依据黄陵庙站流量误差试验资料 ,研究了该站流量测验 、 、 型误差的分布规律 ,计算了流量测验的不确定度 ,并对黄陵庙站现行的测验方案进行了评价。     

Estimation method for mixed-effect coefficient semiparametric regression model

Consider the mixed-effect coefficient semiparametric regression modelZ=X'α+Y'β+g(T)+e, whereX, Y andT are random vectors onR ^p×R ^q×[0, 1], α is a p-dimensional fixed-effect parameter, β is a q-dimensional random-effect parameter (Eβ=b, Cov(β)=Σ),g(.) is an unknown function on [0, 1], e is a random error with mean zero and variance σ², and (X, Y, T) and (β,e), β ande are mutually independent. We estimate α,b andg(.) by the nearest neighbor and the least square method. In this paper, we prove that estimations of α,b have asymptotic normality and obtain the best convergence raten ^−1/3 for the estimation ofg(.). Project supported by the NSFC and the Natural Science Foundation of Zhejiang Province.     

Mixed linear model approaches for analyzing genetic models of complex quantitative traits

New approaches based on general mixed linear models were presented for analyzing complex quantitative traits in animal models, seed models and QTL (quantitative trait locus) mapping models. Variances and covariances can be appropriately estimated by MINQUE (minimum norm quadratic unbiased estimation) approaches. Random genetic effects can be predicted without bias by LUP (linear unbiased prediction) or AUP (adjusted unbiased prediction) methods. Mixed-model based composite interval mapping (MCIM) methods are suitable for efficiently searching QTLs along the whole genome. Bayesian methods and Markov Chain Monte Carlo (MCMC) methods can be applied in analyzing parameters of random effects as well as their variances. Projects supported by NSFC (39670390, 39893350) and the NIH Grant GM32518     

小麦品种(系)的灰色关联度分析与综合评判

应用灰色关联度分析方法 ,对我所近期育成的 1 1个小麦品种 (系 )的 1 0个主要性状进行了分析 ,结果表明 :依各品种的灰色关联度排序而进行的综合评判与品种 (系 )的实际表现是一致的。V8(831 8)、V10 (872 6 )、V1(8946 )和V2 (91 0 1 - 6 )综合性状好 ,表现出产量高 ,品质较好 ,稳产性好等优点     

A test strip for the estimation of urea in serum

We have developed a biostrip for determination of urea in serum. The test strip is based on enzymatic assay where urease has been immobilized on the chromatographic paper along with chromogen, phenol red. The chromogen is easily soluble in water and does not require other components for the color change. Serum urea reacts with urease and water to liberate ammonia and carbon dioxide. The liberated ammonia changes the pH of the reaction medium, which is monitored by the chromogen phenol red. A single step working reagent strip has been developed and the reaction is completed within 50 seconds at room temperature. With this test strip urea concentration is measured in serum as low as 0.15 g/L. The speed and convenience of determining urea in serum by this strip instantly makes it well suited for individuals, physicians and emergency centres.