气候因子对油松林蒸发散的影响

测定和分析了2006年4至10月秦岭火地塘林区油松林气候因子和净辐射的变化,采用波文比能量平衡法计算出潜热通量值,同时将潜热通量分为蒸腾通量和蒸发通量。在以上研究的基础上,利用汽化潜热进一步计算出秦岭火地塘林区油松林林地的蒸发量和油松林群落的蒸腾量。并对其与各气候因子的关系进行了主成份分析。     

运用表观热惯量遥感地表蒸散——以河北省易县崇陵流域为例

现有遥感地表蒸散的方法是基于地表热量平衡方程,先求出地表净辐射通量、土壤热通量和显热通量,再用余项法求出潜热通量。地表净辐射通量和显热通量的计算需空气温度、风速和地表粗糙度等非遥感参数,并且涉及到空间插值问题,由此增加了估算的复杂性并降低了估算的精度。引入反映地物固有热特性的物理参数一表现热惯量,结合地表辐射温度,充分利用遥感较易获取的这两个参数来估算地表蒸散,可弥补上述不足。利用河北省易县崇陵流域卫星过境同步观测的地面资料,以2007年5月28日过境的LANDSAT／TM作为数据源,尝试利用表现热惯量来遥感地表蒸散的新途径。首先根据像元表现热惯量和地表辐射温度等遥感参数反演出像元的大气下行辐射,进而估算出地表净辐射通量;其次,利用表现热惯量估算出波文比,再根据波文比时地表净辐射通量进行切割,然后代入地表热量平衡方程中,直接估算出地表潜热通量;最后,计算出崇陵流域日地表蒸散量,并获取其空间分布图。这种方法避开了估算显热通量的中闻环节,可操作性更强。     

集成概念空间与潜在语义索引的文本聚类检索研究

信息环境的异构性、动态性与海量性使传统基于自然文本的信息检索方法与技术面临极大挑战,集成概念空间理论与潜在语义索引技术能为这种困境提供一些解决方案.在分析概念空间内涵与特征的基础上,利用潜在语义索引原理讨论了概念提取方法、同义词近义词处理方法及基准向量的生成方法,分析了网络条件下基于概念空间的文本分类、聚类检索基本机制,最后给出了完善概念空间的自学习机制.     

基于隐含主题模型的异常行为分析

针对目前多数异常行为分析方法没有考虑场景,提出一种基于隐含主题模型的异常行为分析方法. 提取场景的颜色和纹理特征,利用K-means对特征聚类,形成视觉单词,利用pLSA模型将视觉单词分为若干语义主题区域,生成场景描述. 组合轨迹特征与场景语描述,生成组合特征向量,再利用CRF对组合特征向量建模,通过训练估计模型参数,利用模型推断,分析异常行为. 实验表明,本文方法对特定场景的异常行为可以较为准确地分析.     

基于潜在语义分析和改进的HS-SVM的文本分类模型研究

为提高文本分类的准确性与效率,提出一种基于潜在语义分析和改进的超球支持向量机的文本分类模型。该模型利用潜在语义分析进行特征抽取,消除同义词和多义词在文本表示时所造成的偏差,实现文本向量的降维。针对超球重叠区域的文本分类问题,设计一种新的决策方法-基于密集度的决策策略。实验结果表明,该模型在类别数目较小时具有较好的分类效果,改进的算法有效可行。     

Profiles of teacher-child interaction quality in preschool classrooms and teachers’ professional competence features

This paper investigates early childhood education (ECE) teachers’ self-reported and observed teacher-child interaction quality (TIQ) and the associated teachers’ professional competence features using a latent profile analysis (LPA) approach to identify the variations in the quality of classroom experiences in Chinese preschools. A total of 164 female preschool teachers aged 20–58 participated in this study. The analysis and discussions focus on four identified profiles of teachers: low-quality teachers (n = 9) characterised by lowest scores in both observational and self-reported TIQ; self-overestimated teachers (n = 59) with relatively low observed CLASS scores but high self-reported TIQ; self-underestimated teachers (n = 76) scoring relatively high in observed TIQ but low in self-assessed TIQ and low-level self-efficacy; and genuine high-quality teachers (n = 20) rated highest in both observational and self-reported TIQ. Findings on specific educational and psychological characteristics of the four profiles of teachers that we have identified through an LPA provide insights into teacher training in China.     

Using a theoretical model of communal coping to understand changes in language brokers’ coping patterns: Implications for Latina/o early adolescents’ brokering stress and efficacy

Language brokering occurs when immigrant youth linguistically and culturally mediate for family and members of U.S. mainstream culture. Under some circumstances, brokering can be stressful. Based on a theoretical model of communal coping, this study utilized two waves of survey data from 342 Latina/o sixth- to eighth-grade students to identify different types of copers: (a) communal copers, (b) tentative copers, and (c) declined-ownership copers. Communal copers reported greater brokering stress than tentative brokers in the middle of the year, but not by the end of the year. Communal copers reported greater brokering efficacy than tentative copers in the middle and end of the year. Declined-ownership copers consistently had the lowest brokering stress and moderate brokering efficacy.     

表现性:文学语言的审美解读

符号的诗意在于其表现性,语言的表现性是文学诗意所在。表现性语言关注的是语言的形式自身,它的情感性、体验性,消解了再现性语言的客观性、真实性,并调动读者参与对语言符号想象与创造的热情。文学语言的审美价值具体体现在情感形式化,语义建构性,符号意味性等方面。     

Detecting Appropriate Trajectories of Growth in Latent Growth Models: The Performance of Information-Based Criteria

Latent growth modeling (LGM) is a popular and flexible technique that may be used when data are collected across several different measurement occasions. Modeling the appropriate growth trajectory has important implications with respect to the accurate interpretation of parameter estimates of interest in a latent growth model that may impact educational policy decisions. A Monte Carlo simulation study was conducted to examine the accuracy of six information-based criteria (i.e., AIC, CAIC, AICC, BIC, nBIC, and HQIC) when selecting among various growth trajectories modeled using LGM under different sample size, number of time points, and growth trajectory scenarios. The accuracy of the information criteria generally improved as sample size increased. The cubic and linear growth models were distinguished most accurately by the information criteria. All of the nonlinear models were more easily distinguished as the number of time points increased. The comparative performance of the six information criteria was dependent upon the manipulated conditions. Implications of the findings are discussed.     

孟加拉湾潜热通量与陕西秋季9-10月降水的关系

利用1979-2011年秋季9-10月陕西96个台站的逐日降水资料和NCEP/NCAR再分析月平均资料,分析了孟加拉湾潜热通量与陕西秋季降水的关系,指出了影响陕西秋季旱涝的热源关键区域,并就其影响陕西秋季旱涝的成因机制进行初步分析,得出以下结论:陕西秋季降水与孟加拉湾主体海域的潜热通量变化为显著负相关,当该海域潜热通量偏弱时,乌拉尔山高压偏强,西太平洋副热带高压位置偏西偏北,孟加拉湾至青藏高原南侧多低槽活动,形成了有利于陕西秋季降水的环流形势,同时,陕西地区的偏南水汽输送增强,大气辐合上升运动也增强,陕西秋季降水偏多的可能性较大。此外,孟加拉湾上一年冬季、当年夏季的潜热通量大小与秋季的有显著正相关关系,因此,该海域上一年冬季、当年夏季的潜热通量强弱可以作为预测陕西秋季降水多寡的重要参考。