Activity recognition and intensity estimation in youth from accelerometer data aided by machine learning

Physical activity monitoring for youth is an area of increasing scientific and public health interest due to the high prevalence of obesity and downward trend in physical activity. However, accurate assessment of such activity remains a challenging problem because of the complex nature in which certain activities are performed. In this study, we formulated the issue as a machine learning problem—using a diverse set of 19 physical activities commonly performed by youth—via two approaches: activity recognition and intensity estimation. With the aid of training data, we implemented a distance metric learning method called DML-KNN that utilizes time-frequency features and is capable of effectively classifying both continuous and intermittent movement in youth subjects. Four different time-frequency feature extraction methods were then systematically evaluated. Our results show that the DML-KNN method performed competitively, especially when using features extracted by the Tamura method for intensity estimation, and by the Square Coefficient method for activity recognition.     

Linux下连续媒体文件系统研究

Linux是Internet时代最辉煌的成果之一,它已经成为Internet上最受欢迎的网络操作系统。人们通过Linux提供面向Internet的各种服务,范围从WWW到网上直播。但基于Linux的高质量视频点播服务（VOD）鲜见有人研究。文章正是在这种背景下提出了Linux下的连续媒体文件系统（LCMFS）,将其作为基于Linux的高质量视频点播服务系统的底层支撑。文章先介绍了与Linux相关的背景知识,接着对Linux的现有文件系统—Ext2文件系统的结构进行剖析,指出其在处理连续媒体文件时的不足之处,然后据此提出了LCMFS的设计思想和原则,并阐述了LCMFS的设计及实现方案,最后对LCMFS的性能进行了分析和测试。     

Optimization of Industrial Structure Considering the Uncertainty of Water Resources

This paper developed a stochastic linear fractional programming model for industry optimization allocation base on the uncertainty of water resources incorporating chance constrained programming and fractional programming. In this paper, the stochastic linear fractional programming is used in the real word. The development SLFP has the following advantages: (1) The model can compare the two aspects of the targets; (2) The model can reflect the system efficiency intuitively; (3) The model can deal with uncertain issues with probability distribution; (4) The model can give different optimal plans under different risk conditions. The model has a significant value for the industry optimization allocation under uncertainty in local and areas to achieve the maximum economic benefits and the full use of the water resources.     

基于消除地方高校成长上限基模的实证研究——以江西M学校为例

本文基于系统动力学反馈基模分析方法,在分析江西地方高校发展的成长上限基模和对策基模的基础上进行实证研究,引入相关数据,构建消除成长上限基模的顶点赋权模型,并提出综合对策思考。     

云南村镇垃圾收转运系统建设探讨

对虚拟的垃圾收运项目区域,从覆盖范围的确定、收集方式的选择、收运设施的设置、收运线路的规划4个方面做了较为全面的分析和研究,期望村镇垃圾收转运系统的设计和实施能够实用、适用,并对云南省同类型的村镇垃圾收转运系统建设具有借鉴意义。     

水口水电厂设备状态监测与诊断分析系统

结合工程实践,全面地描述了水口水电厂机组、主变的状态监测与诊断分析系统,包括总体目标和设计原则,系统总体结构,监测范围和测点布置,软件系统组成,系统的主要功能及应用。     

基于嵌入式系统开发平台的设计与实现

本文首先介绍了EVB2107评估板、评估板的系统开发工具和集成开发环境,然后对扩展板上各模块都从原理入手结合该模块要实现的功能说明其设计思想和实现原理,并就各模块驱动程序的编程思想及流程进行了论述。     

Characterization of (Y,Gd) BxV1-xO4-x:Eu Phosphor Prepared by Coprecipitation Reaction

White body-color (Y, Gd)BxV1- xO4-x :Eu3 phosphors were prepared by coprecipitation reaction. Under VUV excitation at 147 nm, the red emission colorimetric purity of (Y, Gd)BxV1- xO4-x :Eu3 phosphor is much better than that of commercial PDP (plasma display panels) phosphor (Y, Gd)BO3:Eu3 . But its relative emission intensity is only about 90% of the commercial phosphor.     

用NaI(Tl)探测器测量γ辐射场剂量特性的加权积分法研究

辐射场剂量特性的测量可以通过剂量率仪或谱 剂量转换的方法来实现。其中一种谱 剂量转换的方法是通过一个G(E)函数 ,把测得的结果直接换算成剂量而不需解谱。本文采用这种方法 ,对一个75mm× 75mm的NaI(Tl)探测器的能谱特性进行测量与分析 ,算出了该晶体的G(E)函数值及估计的误差 ,并用此方法与高气压电离室作了比对测量