应用数理统计解决实际问题的探讨

数理统计是数学的一个重要分支,它主要研究如何以有效的方法去收集、整理与分析带有随机性影响的数据,从而对考察的问题做出推断和预测,直至为采取某种决策提供依据和建议。本文通过讲解数理统计中的相关概念,联系生产实践的具体实例,解决相应的统计问题,对生产实践有一定的帮助。     

《国家学生体质健康标准》与《学生体质健康标准(试行方案)》的比较研究

通过对6 517名大学生的身高标准体重、肺活量、坐位体前屈、台阶试验、立定跳远等测试项目进行<学生体质健康标准(试行方案)>(简称<老标准>)与<国家学生体质健康标准>(简称<新标准>)的评价比较,探讨了<新标准>在测试项目、权重系数、评价等级、评分标准等方面的合理性与科学性.结果表明,<新标准>中测试内容更加丰富,但选测项目仍然分类不清;权重系数的分配更加合理;评价等级的调整幅度较小,但评分标准大幅提高,学生的体质健康测试数据反映出新老标准间的各等级通过率存在非常显著的差异,采用<新标准>评价的不及格比例明显增大,从原来的0.3%提高到23.9%,而优良比例却由原来的60.2%降低到27.5%.因此,建议对<新标准>中部分项目的评分标准进行进一步的完善和优化.     

Estimation versus falsification approaches in sport and exercise science

There has been a recent resurgence in debate about methods for statistical inference in science. The debate addresses statistical concepts and their impact on the value and meaning of analyses’ outcomes. In contrast, philosophical underpinnings of approaches and the extent to which analytical tools match philosophical goals of the scientific method have received less attention. This short piece considers application of the scientific method to “what-is-the-influence-of x-on-y” type questions characteristic of sport and exercise science. We consider applications and interpretations of estimation versus falsification based statistical approaches and their value in addressing how much x influences y, and in measurement error and method agreement settings. We compare estimation using magnitude based inference (MBI) with falsification using null hypothesis significance testing (NHST), and highlight the limited value both of falsification and NHST to address problems in sport and exercise science. We recommend adopting an estimation approach, expressing the uncertainty of effects of x on y, and their practical/clinical value against pre-determined effect magnitudes using MBI.     

大学生健身意识和健身行为对体质影响的追踪研究

摘要：目的：探讨影响大学生体质状况的健身意识和健身行为因素,构建影响大学生体质水平的健身意识和健身行为模型,为提高大学生体质与健康水平提供理论借鉴和模型参考。方法：运用广义估计模型（GEE）分析大学生体质的影响因素,以健身意识和健身行为因素（共15个指标）为自变量,山西省8所大学385名大学生（2011—2014）3年的纵向追踪体质测试成绩为因变量,控制年龄、性别2变量作用,构建大学生体质水平与健身意识和健身行为模型。结果：大学生体质水平与健身意识和健身行为模型指标为锻炼对健康的作用、消遣娱乐的健身目的、锻炼运动量、自行车和力量健美项目。回归方程如下：?=36.07+1.96X消遣娱乐的健身目的+4.25X锻炼对健康作用+2.71X自行车+3.52X力量健美+ 21.86X运动量1+23.84X运动量2+24.3X运动量3+26.22X运动量4+24.08X运动量6+21.11X运动量9。结论：1)健身意识层面提高大学生体质水平,“加强大学生对运动促进健康的认识”、“宣传运动带来快乐的理念”是两个突破口。2)提高大学生体质水平最有效周训练量为：每周3～4次×每次30～60 min。3)提高大学生体质水平有效的运动形式为有氧训练（如自行车）和/或力量训练。     

Basketball lay-up – foot loading characteristics and the number of trials necessary to obtain stable plantar pressure variables

This study aimed (1) to profile the plantar loading characteristics when performing the basketball lay-up in a realistic setting and (2) to determine the number of trials necessary to establish a stable mean for plantar loading variables during the lay-up. Thirteen university male basketball players [age: 23.0 (1.4) years, height: 1.75 (0.05) m, mass: 68.4 (8.6) kg] performed ten successful basketball lay-ups from a stationary position. Plantar loading variables were recorded using the Novel Pedar-X in-shoe system. Loading variables including peak force, peak pressure, and pressure–time integral were extracted from eight foot regions. Performance stability of plantar loading variables during the take-off and landing steps were assessed using the sequential averaging technique and intra-class correlation coefficient (ICC). High plantar loadings were experienced at the heel during the take-off steps, and both the heel and forefoot regions upon landing. The sequential estimation technique revealed a five–eight trial range to achieve a stable mean across all plantar loading variables, whereas ICC analysis was insensitive to inter-trial differences of repeated lay-up performances. Future studies and performance evaluation protocols on plantar loading during basketball lay-ups should include at least eight trials to ensure that the measurements obtained are sufficiently stable.     

利用秒表法找转子静平衡

泵与风机的振动常常是由于转子不平衡不良引起的,现在火力发电厂中高压、高速的大型泵与风机对转子精确平衡的要求更高,特别是在检修、更换转子上的零件后,找平衡成为检修中十分重要的环节,其中秒表法找转子静平衡由于操作简单、省时、误差小等诸多优点而被广泛的应用。     

基于级联特征网络的人体姿态估计

为了解决关键点检测精度不均和整体关键点检测精度不高等问题,基于级联特征网络,通过构建主体网络多分支、多阶段、多分辨率的方式从输入图像中提取丰富特征,并通过微调网络中的级联和在线关键点挖掘以提高整体关键点检测精度.采用自顶向下的方法在MPII数据集上与目前先进方法进行对比实验,分别使用20000张图像进行训练,5000张...     

功率谱估计的Welch方法中的窗函数研究

在经谱估计领域,由Ｗｅｌｃｈ提出的修正周期图法得有效的应用。本文使用Ｍａｔｌａｂ对于Ｗｅｌｃｈ方法的估计特征进行了分析,着分析了窗函数的影响,指出了它的优势与不足。     

MIXED LINEAR MODEL APPROACHES FOR ANALYZING GENETIC MODELS OF COMPLEX QUANTITATIVE TRAITS

ＩＮＴＲＯＤＵＣＴＩＯＮＭａｎｙｇｅｎｅｔｉｃｍｏｄｅｌｓｂａｓｅｄｏｎｔｈｅａｐｐｒｏａｃｈｏｆＡＮＯＶＡ (ａｎａｌｙｓｉｓｏｆｖａｒｉａｎｃｅ)ｗｅｒｅｄｅｖｅｌ ｏｐｅｄｂｙＦｉｓｈｅｒ(1 92 5) .Ｓｏｍｅｏｆｔｈｅｓｅｍｏｄｅｌｓ,ｅ.ｇ .ＮＣｄｅｓｉｇｎＩａｎｄＩＩ(Ｃｏｍｓｔｏｃｋｅｔａｌ.,1 952 ;Ｈａｌｌａｕｅｒｅｔａｌ.,1 981 ) ,ｄｉａｌｌｅｌｍｏｄｅｌｓ(Ｙａｔｅｓ,1 94 7;Ｇｒｉｆｆｉｎｇ,1 956;ＧａｒｄｎｅｒａｎｄＥ ｂｅｒｈａｒｔ,1 966) ,ａｒｅｓｔｉｌｌｗｉｄｅｌｙｕｓｅｄｂｙｐｌａ…     

预应力结构框架梁设计中预应力筋的估算

随着大跨度建筑结构的发展,预应力结构在建筑结构中得到广泛的应用。现对预应力混凝土结构框架梁预应力筋和非预应力筋的估算方法进行了归纳总结,指出了各自的使用范围和计算过程,有较实用的参考价值。