瞬态Oseen方程的全离散局部投影稳定化方法

研究了非定常的Oseen方程的局部投影全离散有限元方法,证明了该格式只需在投影空间和近似空间满足局部弱的inf-sup条件的情况下存在唯一解,给出了稳定性证明,使用一个具有正交性的插值得出误差估计.     

一维粘弹性问题的广义差分法

讨论了一维粘弹性问题的广义差分法．对这类问题的有限元方法的研究已有部分工作．本文将应用广义差分法离散一堆粘弹性问题，得到最优的W^1,p和L^p(2≤P≤∞)模误差估计及广义差分解uk与广义的Ritz-Volterra投影Vku之间的超收敛的W^1,P(2≤p≤∞)模估计。     

国家情报评估与决策的关系——基于多源流理论和认知心理学双重视角

[目的 /意义]《国家情报评估》被认为是美国情报界最正规和最高水平的战略分析产品.对国家情报评估与决策的关系深入研究,可有助于我国完善科学决策体系,对国家治理体系现代化建设大有裨益.[方法/过程]基于多源流理论和认知心理学,从建议采纳视角出发构建出国家情报评估与决策的影响机制模型,借助模糊集定性比较分析法(fsQCA)...     

Psychometric Properties of IRT Proficiency Estimates

Psychometric properties of item response theory proficiency estimates are considered in this paper. Proficiency estimators based on summed scores and pattern scores include non-Bayes maximum likelihood and test characteristic curve estimators and Bayesian estimators. The psychometric properties investigated include reliability, conditional standard errors of measurement, and score distributions. Four real-data examples include (a) effects of choice of estimator on score distributions and percent proficient, (b) effects of the prior distribution on score distributions and percent proficient, (c) effects of test length on score distributions and percent proficient, and (d) effects of proficiency estimator on growth-related statistics for a vertical scale. The examples illustrate that the choice of estimator influences score distributions and the assignment of examinee to proficiency levels. In particular, for the examples studied, the choice of Bayes versus non-Bayes estimators had a more serious practical effect than the choice of summed versus pattern scoring.     

Subspace design of low-rank estimators for higher-order statistics

Higher-order statistics (HOS) are well known for their robustness to additive Gaussian noise and ability to preserve phase. HOS estimates, on the other hand, have been criticized for high complexity and the need for long data in order to maintain small variance. Since rank reduction offers a general principle for reduction of estimator variance and complexity, we consider the problem of designing low-rank estimators for HOS. We propose three methods for choosing the transformation matrix that reduces the mean-square error (MSE) associated with the low-rank HOS estimates. We also demonstrate the advantages of using low-rank third-order moment estimates for blind system estimation. Results indicate that the full rank MSE corresponding to some data length N can be attained by a low-rank estimator corresponding to a length significantly smaller than N.     

线性回归模型中一类式子的推导

线性回归中的最小二乘估计具有线性无偏估计类中方差最小的性质,而这个性质的证明较为复杂,许多文献都予以省略,复相关系数的定义更是直接给出,并未从统计意义上加以解释,回归方程显著性检验所给出的统计量往往是从约束最小二乘出发得到,本文利用简单方法来推导这些性质,并且导出检验统计量的分布,解释了复相关系数的统计意义,以及回归模型中不相关的推导.     

Sex differences in self‐estimation of multiple intelligences among Portuguese adolescents

This study investigated the relationship among sex, attitude toward intelligence, and self‐estimation of multiple intelligences for self and parents among Portuguese adolescents in secondary schools. Two hundred and forty‐two adolescents estimated their own and their parents' IQ scores on each of Gardner's 10 multiple intelligences: verbal (linguistic), logical (mathematical), spatial, musical, body‐kinesthetic, interpersonal, intrapersonal, existential, spiritual, and naturalistic. They also answered six simple questions concerning intelligence and intelligence tests. There were various sex differences in self‐estimated IQ: males rated themselves higher on overall, mathematical, spatial, intrapersonal, spiritual, and naturalistic IQ compared with females. Multiple regressions indicated that verbal, logical, and intrapersonal intelligence were significant predictors for self and parents overall IQ estimations. Factor analysis of the 10, the 8, and the 7 self‐estimates scores did not confirm Gardner's classification of multiple intelligences. Males were more likely to believe in sex differences in intelligence than females. Results are discussed in terms of the growing literature in the self‐estimates of intelligence, as well as limitations of that approach.     

带右删失数据的非线性随机效应模型参数估计

本文讨论了带右删失数据的非线性随机效应模型的参数估计,给出Gauss-Newton迭代法和改进后的Gauss-Newton迭代法,根据参数估计和算法给出数值模拟,验证了参数估计和算法的可行性.     

Weighted approximation of functions with singularities by Bernstein operators

As an important type of polynomial approximation, approximation of functions by Bernstein operators is an important topic in approximation theory and computational theory. This paper gives global and pointwise estimates for weighted approximation of functions with singularities by Bernstein operators. The main results are the Jackson＇s estimates of functions f∈ （Wwλ）2 andre Cw, which extends the result of （Della Vecchia et al., 2004）.