The Difficulty of Sit-Ups Tests: An Empirical Investigation

Abstract

This study estimated the difficulty of various sit-ups tests using an item response theory (IRT) model, the Rasch Poisson Counts model Scores were obtained on 18 sit-ups tests. All tests were thought to vary in difficulty based on clinical observations. Item difficulty was defined by the Poisson model as the difficulty of Step 1, where the difficulty of a step represented the difficulty of completing a sit-up. The difficulty values of the tests ranged from ?4.02 to ?3.57. The easiest test was executed with hands on thighs and feet anchored. Most tests had good fit values. The results demonstrated that a variety of sit-ups tests can provide a range of difficulties and variety in forming a sit-ups test bank.     

网页更新预测算法研究现状

互联网的一个重要性质是网络中的网页信息随时发生着更新。在Web信息迅速增长的今天,网页更新的预测和确定成为了一个备受关注的课题。介绍了作为网页更新预测模型的泊松模型,并根据该模型的各种缺陷分析对网页更新预测算法的现状进行了阐述,同时对未来的研究方向进行了展望。     

基于负二项回归的水上交通事故分析与预测

寻找导致船舶损伤和事故伤亡原因的可能因素和对水上交通事故趋势预测一直是水上交通事故研究的焦点.基于事故因果关系的统计数据,分析港区航道及附近水域水上交通事故的伤亡人数与事故船舶类型、事故种类、事故发生时间、事故发生地理位置等因素之间的关系,通过比较泊松和负二项两种概率分布模型回归的结果,确定负二项分布形式的事故预测模型.研究表明,基于负二项回归的水上交通事故分析与预测方法具有适用性.     

求电磁场问题数值解的随机过程模拟

本文提出一种模拟的随机过程,据其概率模型,可运用Monte Carlo方法求解电磁场Poisson位的数值解。     

我国优秀男子跳远运动员起跳技术的运动学分析

通过运用献资料法、统计法、比较分析法等研究方法，对我国的11名优秀男子跳远运动员和国外6名优秀跳远运动员在起跳阶段有关的运动学参数进行比较分析，结果表明我国优秀运动员助跑速度低，腾起垂直速度小，腾起角度偏小。“跑不快，跳不起”仍是我国跳远运动员的共性。运动员助跑的绝对速度能力低，起跳腿的专项力量素质差，是制约我国跳远运动员跳远成绩进一步提高的关键因素。     

三级跳远运动员的训练负荷量分析及关键性训练因素研究

对三级跳远运动员的训练负荷量分析及关键性训练因素进行剖析 ,不同级的运动员的训练负荷量的结构中 ,一般训练负荷量和发展性负荷量在所占的比重存在不同的比例。关键性训练因素对三级跳远运动员成绩所起的作用有训练负荷因素、身体机能因素、教练因素占有主导作用     

一类随机泊松系统的解

考虑一类随机泊松系统,这类系统来自于对一类Lotka-Volterra系统进行Stratonovich型白噪声扰动。给出该系统的解几乎处处存在(全局不爆发)且唯一的充分条件,并进一步证明在这个条件下,解是几乎处处正的和有界的。数值实验对结论进行了验证。     

复合泊松过程及其应用

利用齐次泊松过程的再生性,研究了保险公司的总索赔次数和总索赔额,得到各类索赔的总索赔次数之和构成一齐次泊松过程;而各类索赔的总索赔额之和构成一复合泊松过程.同时考虑了齐次泊松过程与复合泊松过程在保险业风险管理中的应用.     

A new fractional rational Bézier curve

Based on rational Bézier curves given by Ron Goldman, a new fractional rational Bézier curve was first defined in terms of fractional Bernstein bases. Moreover, some basic properties were dicussed and a theorem connected to Poisson curves was obtained. Some examples in this paper were given by the visual results. Project supported by the National Natural Science Foundation of China (Grant No. 10271074)