回归模型的相关性检验

基于经验似然的方法构造了检验统计量,对非参数回归模型中的误差进行了相关性假设检验,获得了零假设下检验统计量的渐近分布为χ2分布.模拟计算表明相关性假设检验的经验似然方法具有较好的功效.     

Rolling-induced microstructure change in Zr_(65)Al_(7.5)Ni_(10)Cu_(12.5)Ag_5 bulk metallic glass

The microstructures and free-volume evolutions of as-cast and pre-annealed Zr65Al7.5Ni10Cu12.5Ag5 bulk metallic glasses during rolling deformation have been investigated. No phase transformation is detected in the as-cast/rolled specimen. However,the structural stability of the glass against plastic deformation is worse after pre-annealing,indicated by nanocrystallization in preannealed/rolled specimens with large deformation degrees. Moreover,with increasing deformation degree,the free-volume content in a ...     

Knowledge Enhanced Pre-Training Model for Vision-Language-Navigation Task

Vision-Language-Navigation(VLN) task is a cross-modality task that combines natural language processing and computer vision. This task requires the agent to automatically move to the destination according to the natural language instruction and the observed surrounding visual information. To make the best decision, in every step during the navigation, the agent should pay more attention to understanding the objects, the object attributes, and the object relationships. But most current methods process all received textual and visual information equally. Therefore, this paper integrates more detailed semantic connections between visual and textual information through three pre-training tasks(object prediction, object attributes prediction, and object relationship prediction). The model will learn better fusion representation and alignment between these two types of information to improve the success rate(SR) and generalization. The experiments show that compared with the former baseline models, the SR on the unseen validation set(Val Unseen) increased by 7%, and the SR weighted by path length(SPL) increased by 7%; the SR on the test set(Test) increased 4%, SPL increased by 3%.     

神经网络与图论

本文讨论了神经网络与图论之间的相互关系：神经网络的深入研究与发展离不开图论，神经网络的深入发展必将对图论中许多问题的进一步研究产生重要的影响。文中论述了图论在神经网络研究中的作用、地位及应用现状，同时概述了神经网络在图论中的应用情况。     

我国建立个人信用体系的问题探讨

完善的市场经济离不开信用经济,我国目前的个人信用经济还不太发达,主要是信用保证缺失,没有完善的个人信用体系。要发展我国的个人信用经济就要打破这个桎梏,学习外国先进经验,结合我们自身的实际,阶段性地建立我国的个人信用体系。     

盐藻多糖提取及初步纯化

对提取β-胡萝卜素后的杜氏盐藻渣中多糖的提取、初步纯化和多糖脱色方法进行了实验研究.实验采用水浸提的方法,考察了提取温度、提取时间、液固比和pH值对盐藻多糖提取率的影响,盐藻多糖的最适提取条件为:提取温度:70℃,提取时间:4 h,液固比:30:1,pH值10,在此条件下,盐藻多糖的提取率为8.63%,多糖含量为65.73%.采用分级醇沉和分步醇沉的方法沉淀多糖,得到醇沉最佳条件为无水乙醇一步醇沉.采用中性蛋白酶水解脱除盐藻多糖提取液中蛋白质,脱除率为61.55%,脱蛋白后多糖含量为70.96%,采用过氧化氢对脱蛋白后多糖提取液脱色,脱色率为78.66%.     

钢纤维高强混凝土抗冲击性能的数值仿真

采用显式动力有限元软件LS-DYNA,对钢纤维高强混凝土的霍普金森压杆冲击试验过程进行了数值仿真,混凝土和霍普金森压杆的本构关系分别采用弹塑性流体动力模型和虎克定律描述,钢纤维的增强与增韧作用则通过钢纤维高强混凝土强度与失效应变来体现.结果表明:试件内部应力趋近于均匀之前,经历了初始状态的应力震荡;试件的破坏稍微滞后于应力峰值;相同的冲击速度下,钢纤维高强混凝土试件各个时刻的破坏程度轻于未掺钢纤维的基体混凝土试件,当基体混凝土试件裂成多块时,钢纤维高强混凝土试件还基本保持整体.数值仿真结果与试验结果有较好的相似性,基本能够反映出试件受力与破坏的特征.     

旅游景区营销问题的分析

文章通过亲自调查后分析了山西灵空山旅游风景区的营销策略,指出了一些问题:即旅游景区的市场定位要注意与周边景区市场定位的区别:旅游景区的营销要注意对组织市场的营销;在旅游景区的营销过程中要形成整个企业的VI识别系统:旅游景区的营销要发挥市场机制的作用.     

甲醇自发点火特性研究

从实验和数值模拟两方面探讨了甲醇的热点火特性。实验中应用快速压缩机得到了温度与点火延迟期的关系。计算中采用了基元化学反应动力学模型,给出了压力、温度、产物及主要中间反应体的变化历程。对助燃剂二叔丁基过氧化物的活化作用进行了理论分析。