基于局部信息相似性的学科引证知识扩散动态链路预测研究

在知识经济时代,学科知识的传播与扩散促进了学科的协同、交叉、融合、发展与创新。文章利用复杂网络算法对学科引证知识扩散时序演化网络进行动态链路预测分析,以期探索学科知识流动结构变化及演进态势,为学科知识管理及决策制定提供可资借鉴的理论和实践参考。文章以学科引证知识扩散时序演化网络结构信息为基础,采用10项基于局部信息的相似性指标分别对无权和加权知识扩散网络进行动态链路预测分析,并将各指标的预测性能进行了对比。最后,利用无权RA指标和加权AA指标对学科引证知识扩散态势进行了预测。研究表明:不同指标的预测精度在不同的时间段内会动态变化;在学科引证知识扩散网络中,存在一定程度的弱连接效应;不同链路预测指标在无权和加权学科引证知识扩散网络中的适用性存在一定差异。     

混沌时间序列单变量和多变量重构的预测比较

提出了多变量混沌时间序列相空间延迟重构中延迟时间间隔和嵌入维数的选取方法，给出了多变量混沌时间序列的局部平均预测法，局部线性预测法和BP神经网络预测法等3种非线性预测方法．通过Lorenz系统的仿真计算表明，无论用3种非线性预测方法中的哪一种，多变量混沌时间序列要比单变量混沌时间序列的预测误差小得多，即使前的数据长度只有后的一半，前的预测误差也要小很多．另外从预测误差最小的角度验证了多变量混沌时间序列相空间延迟重构中延迟时间间隔和嵌入维数选取方法的有效性．     

甲醛法测定铵盐中总氮含量的有关问题讨论

对用甲醛法测定铵盐中总氮含量的测定原理、含量计算、以及实验注意条件等进行讨论，确保实验成功，提高样品测定结果的准确度．     

基于卡尔曼滤波的PS-InSAR地表形变预测方法

PS-InSAR是用于监测大范围地表形变的微波遥感技术,可提供精确地表形变信息,但该技术无法对形变趋势进行预测。现有形变预测方法只能预测少数监测点的形变,不适用于大面积预测。针对这些问题,提出一种基于卡尔曼滤波的PS-InSAR地表形变预测方法。结合PS-InSAR方法的技术流程,从理论上推导设计卡尔曼滤波器,通过真实的多时相SAR数据对该方法进行验证。实验结果表明,该算法可充分利用PS-InSAR形变监测信息,有效预测大面积观测区域的形变趋势。     

单源三站外辐射源雷达目标探测性能

论述全向外辐射源雷达空中目标探测系统的主要问题及系统体制损失。针对单源单站（SISO）和单源三站（SITO）两种工作方式,在接收天线阵元数相同的情况下分析探测距离和定位精度。在单源三站条件下推导直角坐标系中的目标速度矢量表达式,并分析速度测量精度。研究结果表明,在一定条件下,单源三站组网方式的空间覆盖范围与单源单站相当,且具有平面定位精度较高,可获得目标速度矢量和技术实现难度小的特点。     

Quiet eye training aids the long-term learning of throwing and catching in children: Preliminary evidence for a predictive control strategy

Abstract

Quiet eye training (QET) may be a more effective method for teaching children to catch than traditional training (TT) methods, but it is unclear if the benefits accrued persist in the long term. Thirty children were randomly allocated into a QET or TT group and, while wearing a mobile eye tracker, underwent baseline testing, training and two retention tests over a period of eight weeks, using a validated throw and catch task. During training, movement-related information was provided to both groups, while the QET group received additional instruction to increase the duration of their targeting fixation (QE1) on the wall prior to the throw, and pursuit tracking (QE2) period on the ball prior to catching. In both immediate (R1) and delayed (R2, six weeks later) retention tests, the QET group had a significantly longer QE1 duration and an earlier and longer QE2 duration, compared to the TT group, who revealed no improvements. A performance advantage was also found for the QET compared to the TT group at both R1 and R2, revealing the relatively robust nature of the visuomotor alterations. Regression analyses suggested that only the duration of QE1 predicted variance in catch success post-training, pointing to the importance of a pre-programming visuomotor strategy for successful throw and catch performance.     

河北省人口老龄化趋势预测及对策研究

运用Elman神经网络模型对2010—2050年河北省人口数进行预测,经过分析得出,河北省的人口老龄化具有以下几个特征:老年人口规模庞大,增长迅速;老龄化程度超前于河北省的经济发展水平,社会负担沉重;老年人口的高龄化趋势明显;老年人口的性别差异较大;老年人口的分布具有明显的差异性等。根据这些特征为河北省应对人口老龄化提供了一些对策建议。     

跳远运动员助跑速度感知能力训练对踏板准确性影响的实验研究

通过问卷调查和实验法对跳远运动员助跑踏板准确性和影响跳远运动员助跑速度感知能力的主要因素进行理论与逻辑分析,根据跳远专项特点优选出9种训练方法,实验组采用优选训练手段,对照组采用常用普通训练手段。在严格控制训练过程及训练条件下,进行为期16周的速度感知能力的训练,保证两组只在训练内容方面不同外,其余方面保持一致。实验后对实验组和对照组再次进行踏板准确性和跳远成绩的测定,结果表明:实验后实验组与对照组的跳远成绩与踏板准确性具有明显的差异性。     

为大型体育竞赛提供有效的信息服务——以湖南省体育信息服务为例

在第10届全运会信息服务研究的基础土,总结经验,对全运会信息服务从组织管理、服务方式、内容、重点及保障等方面进行论述,提出以信息提供、专题研究为主要手段,重点项目、主要对手为主要研究内容,以远期、近期、赛前为时间尺度的三个阶段的团体名次预测等进行信息研究。     

Low-achieving (learning disabled) pupils in year 2 of the primary school in Hungary

We selected 60 low-achieving children from a sample of 263 pupils in Year 2 of the primary school in order to analyse the problems of learning disabilities. We explored two questions: whether teachers evaluate the pupils' school performances correctly; and what kind of relationship exists between the low-achieving pupils' cognitive abilities and their school performance. Methods used were questionnaires, pedagogical tests and traditional psychological tests. We obtained the following results: the teachers generally evaluate the pupils' school performance fairly well, but they are inclined to assume a close correlation between the achievements in different subjects, and the teachers' knowledge of the low-achieving children is more reliable regarding the group of pupils as a whole rather than each pupil individually; and the low-achieving pupils' cognitive learning abilities prove to be significantly weaker than their general intellectual abilities.