Classification of Physical Activity Cut-Points and the Estimation of Energy Expenditure During Walking Using the GT3X+ Accelerometer in Overweight and Obese Adults

This study establishes tri-axial activity count (AC) cut-points for the GT3X+ accelerometer to classify physical activity intensity in overweight and obese adults. Further, we examined the accuracy of established and novel energy expenditure (EE) prediction equations based on AC and other metrics. Part 1: Twenty overweight or obese adults completed a 30 minute incremental treadmill walking protocol. Heart rate (HR), EE, and AC were measured using the GT3X+ accelerometer. Part 2: Ten overweight and obese adults conducted a self-paced external walk during which EE, AC, and HR were measured. Established equations (Freedson et al., 1998; Sasaki et al., 2011) overestimated EE by 40% and 31%, respectively (p < .01). Novel gender-specific prediction equations provided good estimates of EE during treadmill and outdoor walking (standard error of the estimate = .91 and .65, respectively). We propose new cut-points and prediction equations to estimate EE using the GT3X+ tri-axial accelerometer in overweight and obese adults.     

Applying the EFQM model to golf course management

The European Foundation for Quality Management (EFQM) Excellence Model provides guidance and support for business organisations to improve their quality management. This goal is attained by examining the relations among the several criteria that are defined and included in the model – the Enablers and the Results – albeit without going deeply into their empirical correlations. Our research focuses on the sport industry and, more particularly, on golf-related services and facilities. We analyse their management and performance. The goal is to conduct an empirical study of golf courses making up the supply in a Spanish inland region. On the basis of data and assessments contributed by the participating sample – and by resorting to multivariate statistical analysis – we pinpoint the influence of all Enablers identified by the EFQM Model, as well as their impact on the Results criteria. Correlations designed and empirically quantified make it possible for us to confirm the theoretical interrelations that the EFQM Model proposes between the defined criteria. The structural model thus obtained allows us to design a map that plots the relationships across the several criteria defined by the EFQM Model, one which portrays present-day approaches to management put into practice by the golf courses under scrutiny.     

On the vibrations of lumped parameter systems governed by differential-algebraic equations

In this paper, we consider the vibratory motions of lumped parameter systems wherein the components of the system cannot be described by constitutive expressions for the force in terms of appropriate kinematical quantities. Such physical systems reduce to a system of differential-algebraic equations, which invariably need to be solved numerically. To illustrate the issues with clarity, we consider a simple system in which the dashpot is assumed to contain a “Bingham” fluid for which one cannot describe the force in the dashpot as a function of the velocity. On the other hand, one can express the velocity as a function of the force.     

实四元数体上的矩阵方程组的解

研究实四元数体Q上的矩阵方程组,给出矩阵方程组有解的一个充分必要条件及其通解表达式,使计算矩阵的约束逆更为简便。     

A methodology for character recognition and revision of the linear equations solving procedure

Linear equations are valuable for real-world modeling phenomena involving at least one variable. However, verifying if the procedure followed by a human for solving a linear equation was done correctly is still a complicated matter. In this paper, we propose a methodology for the automatic character recognition and revision of the solving procedure of linear equations with one unknown. First, a camera is used to acquire an image of the handwritten solving procedure. Then, the image is pre-processed, and each character and equation lines are segmented. Subsequently, a convolutional neural network (CNN) is used to conduct the character recognition stage. Finally, a comparison rule is applied to revise the solving procedure. The character recognition was verified on a 2800 image data set (2100 for training and 700 for testing), including the ten digits and four symbols: ×, +, -, /. The revision procedure was tested on a data set with 140 handwritten equations (125 for training and 15 for testing). The results revealed that we recognized handwritten characters with an accuracy of 99%, which is similar to the state-of-the-art. Moreover, our proposal revised the solving procedure with an efficiency of 86.66%.     

Kerr度规的解析推导

通过直接求解Emst方程,给出了Kerr度规的解析推导。     

机构学中初始方程组的自动生成

提出与齐次理论［１］相匹配的初始方程组的一般表达式,并给出计算机进行变元分组、自动生成初始方程组和确定初始解的算法。这为构造实数同伦法（笔者另文论述）、求解机构学多解问题奠定了基础。     

论列选主元法在Gauss-Seidel迭代法和SOR迭代中的应用

将迭代法与列选主元的思想相结合,基于Gauss-Seidel迭代法和SOR迭代法,给出了两种改进的解线性方程组的迭代算法.所给的方法扩大了Gauss-Seidel迭代法、SOR迭代法的使用范围,进而使其具有很好的现实应用价值.编写了MATLAB程序对改进的两种Gauss-Seidel迭代法、SOR迭代法进行了验证,同时,通过算例对经典的Gauss-Seidel迭代法、SOR迭代法与改进后的Gauss-Seidel迭代法、SOR迭代法的收敛性以及收敛速度进行了比较.算例结果表明:改进的两种迭代算法相对于原来的Gauss-Seidel迭代法和SOR迭代法,具有使用范围较广,收敛速度更快的优点。     

我国农业环境库兹涅茨曲线的实证研究——基于联立方程模型的估计

使用一个包括污染方程和产出方程的联立方程模型,并且利用我国1995~2005年的省际面板数据,采用二阶段最小二乘法(2SLS)对我国农业环境库兹涅茨曲线(EKC)进行了检验。污染方程的估计结果表明,在人均化肥投入和人均农业产出之间不存在倒U型的EKC关系,而在人均农药施用和人均农业产出之间存在倒U型的EKC关系。产出方程的估计结果表明,人均化肥和农药使用量对人均农业产出均有显著的正向效应,化肥和农药投入与农业产出之间确实存在相互作用。政策含义在于要达到农业产出增长与环境相互协调的目的,必须同时从农业污染和农业要素投入两个方面着手。     

在线性代数中引入线性方程的有效性

本文从线性方程的有效性出发,利用学生中学解方程的知识,从线性方程的角度补充定义了矩阵的秩并说明可逆矩阵对应的线性方程组是每个方程都有效且不矛盾的线性方程组。