数字图像最佳灰度门限的确定

利用基于模式识别决策理论的最大类间距准则,给出了求解最佳分割灰度门限的方法。以三氧 化二铝衬底芯片为算例,利用UMA测度对最大类间距准则和标准双峰准则在分割质量上的差异进行定 量比较。结果表明:最大类间距准则在分割质量和鲁棒性两方面性能均优于标准双峰准则。     

MCMC Sampler Convergence Rates for Hierarchical Normal Linear Models: A Simulation Approach

This paper presents a straightforward method of approximating theoretical bounds on burn-in time for MCMC samplers for hierarchical normal linear models. An extension and refinement of Cowles and Rosenthal's (1998) simulation approach, it exploits Hodges's (1998) reformulation of hierarchical normal linear models. The method is illustrated with three real datasets, involving a one-way variance components model, a growth-curve model, and a spatial model with a pairwise-differences prior. In all three cases, when the specified priors produce proper, unimodal posterior distributions, the method provides very reasonable upper bounds on burn-in time. In contrast, when the posterior distribution for the variance-components model can be shown to be improper or bimodal, the new method correctly identifies convergence failure while several other commonly-used diagnostics provide false assurance that convergence has occurred.     

白石有格无情辨

王国维先生在《人间词话》中评价白石“有格无情”。然白石之“无情”，实则为“深情”，白石“深情”却看似“无情”，与他个人身世经历有关，同时也是他清空骚雅的词学风貌的主体规定性所在，与其推动词的复雅的创作实践，与其诗教观和美学思想的实践和追求是分不开的。     

远程教育——实现高等教育公平的选择

高等教育由于承担着分配职业阶梯和社会角色的作用,能为个人提供较多的升迁机会和较高的回报率,人们对其公平予以更多的关注。论文针对高等教育公平两个主要方面,即教育机会均等和教育活动公平,结合远程教育的本质和特点分析了远程教育对于促进高等教育公平的作用。最后从课程资源、学习支持服务、考评制度和媒体技术四方面指出,远程教育质量的提高是其实现高等教育公平的保证。     

Web 2.0环境下远程学习者自主学习能力的培养

Web2.0网络所具有的特征,丰富了现代远程教学的学习支持服务系统,而远程学习者的学习方法、学习资源的获取方式也随之发生了变化。本文从Web2.0的特征出发,阐述在新的Web2.0网络环境下,如何将Web2.0网络的优点嵌入到远程学习的过程中,并分别从自主学习理论的六个维度,说明在Web2.0环境下提高远程学习者自主学习能力的策略。     

基于资源环境约束视角的中国农业绿色生产率测算及其影响因素解析

传统农业生产率测算方法忽视资源和环境约束,有可能对农业经济增长的绩效产生误判,从而导致政策误导。为此,将资源环境因素引入传统的农业生产率分析框架,采用非径向、非角度的SBM方向性距离函数方法对中国30个省份1998—2011年的农业绿色生产率水平进行测算,并且运用Tobit回归模型对影响农业绿色生产率的因素进行实证研究,结果表明:中国农业绿色生产率水平总体偏低,资源消耗和环境污染已经对中国的农业发展造成了较大的效率损失;不同区域农业绿色生产率差异较大,东部地区农业绿色生产率较高,中部和西部地区农业绿色生产率普遍较低;农村经济发展水平的提高以及农业基础设施投资力度的加大会有效提升农业绿色生产率水平,而农业结构中养殖业比重的上升、城乡收入差距的扩大、工业化程度的提高以及财政支农政策的实施,对农业绿色生产率水平有显著的负面影响。     

Income inequality and solidarity in Europe

This paper studies the relationship between income inequality, a macro-level characteristic, and solidarity of Europeans. To this aim, solidarity is defined as the ‘willingness to contribute to the welfare of other people’. We rely on a theoretical idea according to which feelings of solidarity are derived from both affective and calculating considerations – we derive competing hypotheses relating the extent of income inequality to these ‘underlying’ motivations for solidarity. Using data from the 1999 European Values Study (EVS), we apply multilevel analysis for 26 European countries. Controlling for household income and a range of macro-level characteristics, we find evidence that in more unequal countries people are less willing to take action to improve the living conditions of their fellow-countrymen. This is true for respondents living in both low- and high-income households. According to our theoretical framework, this finding suggests that, at least when measured in terms of ‘willingness to contribute to the welfare of other people’, feelings of solidarity seem to be influenced more strongly by affective, rather than by calculating considerations.     

抛体运动的迭代法求解

用数学上的逐次逼近理论，通过多次迭代，求得抛体的射程和横向偏移的高次近似解。     

从本质特征视角探索中跑与长跑项群的划分

通过对中跑与长跑本质特征的全面分析,认为：中跑应划分为体能主导类无氧耐力性项目,长跑应划分为体能主导类有氧耐力性项目.这种划分符合该项目的本质特征,也为教练在未来时青少年运动员的选才、训练内容的科学安排指明了方向,据此,可以提升中跑训练的科学化水平,改变我国中跑项目落后的现实.     

A Simple Derivation of Deletion Diagnostic Results for the General Linear Model with Correlated Errors

A general, simple and intuitive derivation is provided for diagnostics associated with the deletion of arbitrary subsets for the linear model with general covariance structure. These are seen to be most simply expressed, even for the well-studied case of independent and identically distributed data, in terms of a residual known variously as the conditional residual, the deletion prediction residual and the cross-validation residual. Particularly simple specializations arise when the subsets are of size 1 and of size 2, but the method is easy to apply for all subsets and to conditional deletions.