大跨度拱桁架结构方案优化分析

文章以陕西省榆林市漠海丽江餐饮有限公司餐饮中心生态种植区的钢屋盖结构为研究对象,根据甲方对结构空间、用钢量和对下部结构负荷小的要求,首先用设计程序3D3S8.0对结构进行了初步设计,定出了支座间不拉索和杆、拉索和拉杆3个方案,然后用分析软件ANSYS研究其桁架静力和动力特性,并计算了拉索方案预应力的合理取值,计算结果表明:拉杆方案的用钢量、竖向挠度小且施工难度低,因此,工程中采用了拉杆方案。     

Connecting Internal and External Representations: Spatial Transformations of Scientific Visualizations

Many scientific discoveries have depended on external diagrams or visualizations. Many scientists also report to use an internal mental representation or mental imagery to help them solve problems and reason. How do scientists connect these internal and external representations? We examined working scientists as they worked on external scientific visualizations. We coded the number and type of spatial transformations (mental operations that scientists used on internal or external representations or images) and found that there were a very large number of comparisons, either between different visualizations or between a visualization and the scientists’ internal mental representation. We found that when scientists compared visualization to visualization, the comparisons were based primarily on features. However, when scientists compared a visualization to their mental representation, they were attempting to align the two representations. We suggest that this alignment process is how scientists connect internal and external representations.     

Parallel scheduling strategy of web-based spatial computing tasks in multi-core environment

In order to improve the concurrent access performance of the web-based spatial computing system in cluster,a parallel scheduling strategy based on the multi-core environment is proposed,which includes two levels of parallel processing mechanisms.One is that it can evenly allocate tasks to each server node in the cluster and the other is that it can implement the load balancing inside a server node.Based on the strategy,a new web-based spatial computing model is designed in this paper,in which,a task response ratio calculation method,a request queue buffer mechanism and a thread scheduling strategy are focused on.Experimental results show that the new model can fully use the multi-core computing advantage of each server node in the concurrent access environment and improve the average hits per second,average I/O Hits,CPU utilization and throughput.Using speed-up ratio to analyze the traditional model and the new one,the result shows that the new model has the best performance.The performance of the multi-core server nodes in the cluster is optimized; the resource utilization and the parallel processing capabilities are enhanced.The more CPU cores you have,the higher parallel processing capabilities will be obtained.     

障碍可越路线规划的符号图方法

本文给出２—Ｄ路线规划问题在障碍可越情况下的启发式符号方法．这一方法利用推理规则在由图像信息导出的连通图知识结构上进行启发式符号Ａ搜索以对空间关系进行分析和分类，以符号描述形式给出两声间路线规划方案．     

郑汴一体化地区旅游景区的空间结构分析

旅游景区是旅游区域发展的物质依托,其空间结构影响着旅游区域的空间竞争、资源开发等.本文运用最近邻指数R、β指数、γ指数三种指标和基尼系数分析方法对郑汴一体化地区的旅游景区空间结构进行分析.结果表明:该区域旅游景区在空间上符合核心-边缘分布结构,在总体上呈集聚型分布形态,景区空间连通性较好.最后,提出推动区域旅游共同发展、进一步完善景区间交通网络、实现区域景区联动开发等建议.     

PRC板在工程应用中的干缩形变与改善措施

人造水泥复合板密实性高，抗渗透能力强、干缩值小，但用大幅面的人造水泥复合板预制装配式墙体结构，因干缩引起的墙缝仍不容忽视。本文分别研究了ＰＲＣ板的干缩规律，并给建筑设计和施工提出了改进意见     

基于ARCGIS的塌陷塘水质特征研究及评价——以淮南矿业集团谢桥矿为例

为了解矿区塌陷水体的水质污染特征及规律,结合物理、化学和生物指标,运用营养状态综合指数法及基于ARCGIS的空间差值分析法对淮南矿业集团谢桥矿塌陷塘水质进行了分析与评价。矿区塌陷塘水质pH值呈弱碱性,透明度较低,BOD5、CODMn指标含量较高;用营养状态综合指数法对塌陷塘水质富营养化进行了评价,其污染级别为轻度富营养;运用ARCGIS的空间分析模块,利用总磷、总氮、BOD5、CODMn4个因子的空间插值栅格图建立多因子综合污染模型进行综合评价,得出水体综合水质标准处于地表水Ⅲ类到Ⅳ类之间,水质有待改善。本研究结果为塌陷塘水体水质监管及管理提供科学依据。     

基于多主体建模方法研究空间市场效率的影响

基于多主体建模的方法通过建立记忆叠加模型,研究信息对空间市场效率的影响．模型模拟发现,个体的朋友数量和视野半径对市场聚集度、简单社会熵和市场交易成功率产生显著影响,从而影响市场效率．     

治理黄河泥沙的新途径——小北干流放淤

介绍了黄河泥沙的主要来源及危害,提出了治理黄河泥沙的新举措——小北干流放淤,分析了小北干流放淤的客观性和必要性,指出了小北干流放淤对黄河治理的长远影响。     

基于DEA交叉模型的西部地区生态效率时空变化

建立基于DEA模型的生态效率投入产出指标体系,以2005-2009西部地区11个省份截面数据为样本,采用DEA交叉评价模型和空间对比分析方法,对西部地区生态效率进行时空差异研究.结果表明:从时间上看,西部地区生态效率总体上呈现出增加的趋势,省份之间的差异进一步扩大,其中,陕西一直处于首位,而宁夏一直处于末位.从空间上看,西部地区生态效率存在着明显的区域差异,东南区域整体上要高于西北区域,但是区域间的这种差异呈现出增大的趋势,生态效率分布的重心逐渐向区域中心集中,经济条件好的省份生态效率水平相对较高.最后,依据以上研究发现,提出了相应的建议.