基于Oracle Spatial的空间查询技术及其优化

从Oracle Spatial的空间查询分析出发,结合实例分析了它的查询模型、空间算子以及常用的空间函数,最后给出了Oracle Spatial中空间查询的优化建议。     

区域旅游系统空间结构模式与优化——以中原城市群为例

在分析国内外区域旅游空间结构研究基础上,以中原城市群为例．探讨了区域旅游系统空间结构的模式和优化问题,并通过旅游线路体系的完善和空间结构的重组与优化促使中原城市群旅游区演变为较理想的发展模式。     

论地方高校馆藏实体资源与虚拟资源的整合

文章从地方高校馆藏实体资源和虚拟资源建设现状、地方高校实体资源与虚拟资源的整合措施两个方面对地方高校图书馆的资源建设作了分析,提出了构建科学化的馆藏资源“和谐共建”发展实施规划、通过合理转化进行实体馆藏信息资源与虚拟馆藏信息资源的整合、采用实体资源与虚拟资源的整合新技术、通过多种形式的服务进行实体馆藏信息资源与虚拟馆藏信息资源的整合、通过信息分析进行实体馆藏信息资源与虚拟馆藏信息资源的整合等建议。     

海外并购与金融结构的关系研究

通过对1991—2006年42个国家海外并购与金融结构的关系进行研究,发现金融结构对海外并购的数量和金额有显著影响,因此,优化我国的金融结构有助于“走出去”战略的顺利实施．     

Research in non-equalization machining method for spatial cam

Many kinds of devices with cam have been widely used in various mechanical equipments. However, non-equalization machining for spatial cam trough remains to be a difficult problem. This paper focuses on the analysis of running conditions and machining processes of spatial cam with oscillating follower. We point out the common errors in the biased distance cutting. By analyzing the motion of oscillating follower of spatial cam, we present a new 3D curve expansion model of spatial cam trough-outline. Based on this model, we have proposed a machining method for trochoidal milling with non-equalization diameter cutter. This new method has led to a creative and effective way for non-equalization diameter machining for spatial cam with oscillating follower.     

基于MIDAS/FEA与ANSYS的预应力对比仿真模拟分析

以一根预应力钢筋混凝土梁为例,利用MIDAS/FEA和ANSYS建立有限元模型,MIDAS/FEA模型中的预应力采用桁架单元法和钢筋单元法模拟,ANSYS模型中的预应力采用实体切分法、约束方程法以及节点耦合法模拟。分析结果表明,MIDAS/FEA和ANSYS在预应力作用下的计算结果相近,在静力学领域都能得到较为精确的结果;从建模的难易程度上说,MIDAS/FEA的钢筋单元法最为方便,而ANSYS通常需要运用APDL语言辅助建模,难度相对较大;ANSYS采用节点耦合法模拟预应力时,混凝土实体的网格需要划分较密才能取得较为精确的结果。     

Aged-based differences in spatial language skills from 6 to 10 years: Relations with spatial and mathematics skills

Spatial language is the language of spatial concepts and spatial relationships. Prior research has demonstrated an association between spatial language and spatial thinking in pre-school children. However, there is limited evidence exploring age-based differences in spatial language in older childhood. This cross-sectional study has three main aims. First, we present a novel spatial language measure and show differences in spatial language performance across age groups from 6 to 10 years (N = 155). Second, having demonstrated that our measure is sensitive to age-based progression, we use regression analyses to determine relations between spatial language and performance on a range of spatial tasks (r²:1.2%–9.0%). Third, we investigate the relations between spatial language and different mathematics skills (r²:0.2%–15.4%) and propose mechanisms that may explain these associations. We discuss how these findings lay a foundation for future spatial language interventions as a novel tool which may lead to educational improvements in mathematics.     

Developmental trajectories of children's spatial skills: Influencing variables and associations with later mathematical thinking

Few studies have examined the long-term relations between children's early spatial skills and their later mathematical abilities. In the current study, we investigated children's developmental trajectories of spatial skills across four waves from age 3–7 years and their association with children's later mathematical understanding. We assessed children's development in a large, heterogeneous sample of children (N = 586) from diverse cultural backgrounds and mostly low-income homes. Spatial and mathematical skills were measured using standardized assessments. Children's starting points and rate of growth in spatial skills were investigated using latent growth curve models. We explored the influence of various covariates on spatial skill development and found that socioeconomic status, language skills, and sex, but not migration background predicted children's spatial development. Furthermore, our findings showed that children's initial spatial skills––but not their rate of growth––predicted later mathematical understanding, indicating that early spatial reasoning may play a crucial role for learning mathematics.     

二元经济形态下技术创新双重主体模式的确立

在分析基础科学研究与工程技术发展关系的基础上 ,重新对技术创新的内涵和外延进行了界定 ;根据世界经济发展的基本规律 ,结合我国处于二元经济形态的实际情况 ,提出了我国推进技术创新战略的双重主体模式     

GIS的数据抽象模型的构建和检索

随着地理信息系统(GIS)应用的逐步深入和业务领域的拓展,传统的GIS数据模型不能较好地表达GIS中复杂的空间数据关系,不易实现数据的共享和查询.为此,文中首先构建了一种网络数据抽象模型,该模型能够使异质的、松散的被关联的GIS数据聚集在一起,且是动态更新以提高将来的查询性能;然后提出一种基于此模型的动态检索算法.