Assessing rugby place kick performance from initial ball flight kinematics: development,validation and application of a new measure

The appropriate determination of performance outcome is critical when appraising a performer’s technique. Previous studies of rugby place kicking technique have typically assessed performance based on ball velocity, but this is not the sole requirement. Therefore, a mathematical model of rugby place kick ball flight was developed to yield a single measure more representative of true performance. The model, which requires only initial ball flight kinematics, was calibrated and validated using empirical place kick data, and found to predict ball position with a mean error of 4.0% after 22 m of ball flight. The model was then applied to the performances of 33 place kickers. The predicted maximum distance, a single performance measure which accounted for initial ball velocity magnitude and direction, and spin, was determined using the model and was compared against ball velocity magnitude. A moderate association in the rank-order of the kicks between these two measures (ρ = 0.52) revealed that the relative success of the kicks would be assessed differently with each measure. The developed model provides a representative measure of place kick performance that is understandable for coaches, and can be used to predict changes in performance outcome under different ball launch or environmental conditions.     

Index of microcirculatory resistance: state-of-the-art and potential applications in computational simulation of coronary artery disease

The dysfunction of coronary microcirculation is an important cause of coronary artery disease (CAD). The index of microcirculatory resistance (IMR) is a quantitative evaluation of coronary microcirculatory function, which provides a significant reference for the prediction, diagnosis, treatment, and prognosis of CAD. IMR also plays a key role in investigating the interaction between epicardial and microcirculatory dysfunctions, and is closely associated with coronary hemodynamic parameters such as flow rate, distal coronary pressure, and aortic pressure, which have been widely applied in computational studies of CAD. However, there is currently a lack of consensus across studies on the normal and pathological ranges of IMR. The relationships between IMR and coronary hemodynamic parameters have not been accurately quantified, which limits the application of IMR in computational CAD studies. In this paper, we discuss the research gaps between IMR and its potential applications in the computational simulation of CAD. Computational simulation based on the combination of IMR and other hemodynamic parameters is a promising technology to improve the diagnosis and guide clinical trials of CAD.     

双向航道船舶交通流元胞自动机模型及仿真

为提高整个航道系统的通过能力,避免航道资源闲置浪费,在NaSch模型的基础上制定船舶追越和对遇规则,建立可变道的双向航道船舶交通流元胞自动机模型。通过模拟允许变道和禁止变道两种情况下的船舶交通流,得出船舶流量、平均航速与船舶到达率的关系。研究发现,允许变道可以在不影响交通秩序的前提下有效增加整个航道系统的船舶流量和平均航速:当航道船舶交通流较为密集时,允许变道可以明显增加船舶流量;当航道船舶交通流较为稀疏时,允许变道可以明显增加平均航速。     

细胞色素c与富勒烯衍生物的吸附相互作用

细胞色素c是一种广泛存在在细胞线粒体中的富电子蛋白。它在与纳米材料相互作用的过程中引发自由基的生成,扩大纳米材料的生物毒性。为了在分子尺度上理解其与纳米材料的相互作用,通过分子动力学模拟研究细胞色素c与富勒烯衍生物体系（富勒醇、三丙二酸富勒烯）。分析吸附后体系的能量、均方回转半径、接触原子数以及细胞色素c中的Fe原子到富勒烯衍生物质量中心的距离,进而揭示细胞色素c与富勒烯衍生物相互作用机理。     

宽带激光熔覆送粉喷嘴的结构设计与粉末流场研究

设计一种新型的送粉喷嘴结构,适用于宽带激光熔覆和增材制造。该结构使用多通道出口有效降低粉末流在扫描方向的发散角,通过添加内部整流圆柱调整粉末流在垂直扫描方向上的浓度分布。采用离散相模型,研究该喷嘴结构输出的粉末流场。优化分流圆柱的尺寸,使该送粉喷嘴能够输出浓度分布均匀的宽带粉末流,并沉积出厚度均匀的宽带涂层。     

船舶变频海水系统仿真软件设计与实现

传统的船舶海水系统的培训和操作训练软件是在工频模式的设计工况下工作的,这已不能适应新的减排规则和相关公约要求.本文以载重量为30 000 t的多用途船的海水系统为仿真对象,根据海水系统原理、能量守恒定律和传热学基本理论,建立变频海水系统的数学模型.运用计算机仿真技术模拟该系统的操作和监控功能,在Visual Studio 2010开发环境下采用C#语言实现该系统的相关界面设计和功能仿真.对该系统进行全面的操作和功能测试.结果表明,该系统软件能逼真地反映海水系统在变频模式下的工作状况和实际动态过程.这对提高船员的操作水平及保证操作过程中的可靠性和安全性起到重要作用.     

Examining the Error of Mis-Specifying Nonlinear Confounding Effect With Application on Accelerometer-Measured Physical Activity

Purpose: Some confounders are nonlinearly associated with dependent variables, but they are often adjusted using a linear term. The purpose of this study was to examine the error of mis-specifying the nonlinear confounding effect. Methods: We carried out a simulation study to investigate the effect of adjusting for a nonlinear confounder in the estimation of a causal relationship between the exposure and outcome in 3 ways: using a linear term, binning into 5 equal-size categories, or using a restricted cubic spline of the confounder. Continuous, binary, and survival outcomes were simulated. We examined the confounder across varying measurement error. In addition, we performed a real data analysis examining the 3 strategies to handle the nonlinear effects of accelerometer-measured physical activity in the National Health and Nutrition Examination Survey 2003–2006 data. Results: The mis-specification of a nonlinear confounder had little impact on causal effect estimation for continuous outcomes. For binary and survival outcomes, this mis-specification introduced bias, which could be eliminated using spline adjustment only when there is small measurement error of the confounder. Real data analysis showed that the associations between high blood pressure, high cholesterol, and diabetes and mortality adjusted for physical activity with restricted cubic spline were about 3% to 11% larger than their counterparts adjusted with a linear term. Conclusion: For continuous outcomes, confounders with nonlinear effects can be adjusting with a linear term. Spline adjustment should be used for binary and survival outcomes on confounders with small measurement error.     

旋转整流器式无刷电机加载泄载动态响应特性研究

详细分析、介绍了新研制的15KVA旋转整流器式无刷直流同步拓扑结构、工作原理,并给出了其参数设计要点、实现方法及样机实验数据和Saber仿真波形。结果表明,该系统具有可靠性高、体积小、重量轻及电气性能好,可长期连续运行而不需要保养等特点,对无人驾驶机设计制造有较好的应用前景。     

星卫型虚拟企业敏捷生产计划方法研究

生产计划方法对于提高企业群体的敏捷性具有重要意义 ,本文将延迟生产的应用研究延伸到虚拟企业环境 ,提出了基于延迟生产理论的星卫型虚拟企业模块化生产计划方法。仿真试验表明 ,延迟模块化生产计划的实施 ,具有并行制造的效果 ,与传统星卫型企业群体的生产计划方法相比 ,具有更高的敏捷性     

时间语义加工中内隐空间图式的激活机制

本研究采用实验方法考察时间语义理解中内隐空间图式的激活,借此探讨感知运动经验在抽象语义加工中的作用.实验发现,时间语义加工会激活左右空间编码,引起注意力向时空隐喻映射一致的方向转移(左/早,右/晚).过去时间引起注意力向左转移,促进左侧目标的识别,未来时间引起注意力向右转移,促进左侧目标的识别.实验表明,时间语义加工会...