同异反可靠性系统中故障的分析

从系统工程可靠性出发,引入联系数的和、点积与积的概念以及相应的定理与性质,并利用联系数的点积对同异反可靠性系统中故障问题进行分析,从而探讨了系统工程中串联与并联的可靠度中故障问题的计算方法,解决了系统工程中有关串联与并联的可靠性的问题.     

"信息检索与利用"网络课程辅助系统--智能测试系统的设计

对智能测试系统的开发进行了详细介绍，提出并实现了该系统的两个重要部分——题库系统和网上考试系统，题库系统中的标准化试题系统、试卷系统对提高教学质量起到推动性作用。网上考试系统具有智能性特点。     

运用测试反拨原理优化大学英语教学评估体系

语言测试对课堂教与学总是存在着不同程度的积极或消极影响,此即测试的反拨作用。构建教学评估体系,应充分借鉴测试相关理论,利用测试反拨效应的相关原理,并结合大学英语教学改革实践。     

英语口语测试体系的发展及对英语口语教学的启示

根据英语口语测试理论及口语测试体系的发展变化,介绍了目前国内外主要的口语测试手段,比较了各自的优缺点,并对目前的英语口语教学提出了建议,即培养学生英语口语交际能力,以适应社会对外语人才的要求。     

Effect of computer interfaces on chemistry problem solving among various ethnic groups: A comparison of Pen-Point and Powerbook computers

This study investigated the effect of Pen-Point and Powerbook computers on solving a multiple step chemistry (molaritý) problem among White, Afro-American and Hispanic students (N=60) at the high school level. The screens on both computers were partitioned into a work field and a reasoning field. Both computers were programmed to record the time spent in each field, the number of entries made, and a copy of the entries made. Statistical analysis of data showed that more of the White and Afro-American Pen-Point computer users solved the problem correctly than did students using the Powerbook computer. All three ethnic groups made fewer entries, and took less time using the Pen-Point computer than the Powerbook. Attitude survey results of all ethnic groups showed that more Pen-Point computer users felt comfortable working with computers. Over all, the results suggest that the Pen-Point computer has a more positive effect on the problem solving performance and attitude of students towards computers than the Powerbook computer.     

Fluid balance and hydration assessment during the weight-stable preparation phase in elite youth boxers

This study investigated (i) the prevalence of hypohydration and (ii) association between urinary indices of hydration status and confounding factors (e.g., urine protein content, water intake) in elite youth boxers during their weight-stable phase before competition. Sixteen national champion boxers (all male, 17 ± 1 y) were measured on 3 occasions (baseline, day 3, day 10), 30-day prior to competition. Body mass, total body water, urine specific gravity (USG), osmolality (UOSM) and total protein content (TPC) were evaluated to determine hydration status and fluid balance. Overall macronutrient and water intake were assessed using dietary records. Both UOSM and USG increased from day 3 to day 10 by 16% and 0.4% (P < 0.001), despite athletes being in their weight-stability period, and regardless of ad libitum fluid intake. Hypohydration was universally prevalent among all athletes on both test days with USG: 1.027 ± 0.003 g · mL^?1 and UOSM: 1035 ± 108 mOsmol · kg^?1. An inverse association between mean UOSM values and mean water intake was observed (R = ?0.52, P = 0.04), while TPC was not associated with any urinary dehydration markers (USG, P = 0.51; UOSM, P = 0.61). The present outcomes find that the most prevalent urinary dehydration markers used to classify hydration status in competition exhibit large variability, even during weight-stable periods.     

矿井自动排水系统综述

叙述矿井自动排水系统的组成和工作方式,介绍了矿井自动排水系统的分类和某些系统硬件的安装及作用,讲述大多数矿井自动排水系统具备的特点,最后分析系统中PCL的可靠性及其解决办法。     

浅谈免棱镜全站仪在工程测量中的应用

介绍了免棱镜全站仪的工作原理及优缺点,对Leica TS06全站仪在无反射棱镜条件下的测距性能进行了测试,得出了测距边长、测量目标的属性对免棱镜测距的影响关系,介绍了免棱镜全站仪在工程项目测量中的应用实例。     

农村信息化公众满意度指数模型研究

文章首先定义了农村信息化公众满意度指数的内涵,然后在定性研究和数理检验的基础上开发了农村信息化公众满意度测量表,并建立了农村信息化公众满意度指数模型.最后,依据上海郊区农村信息化调查数据,运用结构方程模型估计技术对测评模型进行了检验和参数求解.研究表明,文章建立的农村信息化公众满意度指数模型拟合度较高;另外,通过样本数据,得到了各潜在因子之间的路径系数以及可测变量的载荷系数,并对各潜在变量之间的相关关系进行了系统分析,文章在最后就研究发现的农村信息化过程不足提出了建议.     

The Reliability of Distance Run Tests for Children in Grades K—4

Abstract

The purpose of this study was to determine test–retest reliability for the 1-mile, 3/4-mile, and 1/2-mile distance run/walk tests for children in Grades K—4. Fifty-one intact physical education classes were randomly assigned to one of the three distance run conditions. A total of 1,229 (621 boys, 608 girls) complied the test–retests in the fall (October), with 1,050 of these students (543 boys, 507 girls) repeating the tests in the spring (May). Results indicated that the 1-mile run/walk distance, as recommended for young children in most national test batteries, has acceptable intraclass reliability (.83 < R < .90) for both boys and girls in Grades 3 and 4, has minimal (fall) to acceptable (spring) reliability for Grade 2 students (.70 < R < .83), but is not reliable for children in Grades K and 1 (.34 < R < .56). The 1/2 mile was the only distance meeting minimal reliability standards for boys and girls in Grades K and 1 (.73 < R < .82). Results also indicated that reliability estimates remained fairly stable across gender and age groups from the fall to spring testing periods, with the exception of the noticeably improved values for Grade 2 students on the 1-mile run/walk test. Criterion-referenced reliability (P, percent agreement) was also estimated relative to Physical Best and Fitnessgram run/walk standards. Reliability coefficients for all age group standards were acceptable to high (.70 < P < .95), except for Fitnessgram standards for 5-year-old girls on the 1-mile test for both fall and spring and for 6-year-old boys and girls on the 1-mile test administered in the spring.