测验质量的三维审视及对命题的诉求

本文建立了评估测验质量的稳定性、自洽性和可推广性三个指标,并运用它们对测验质量进行初步分析,在此基础上讨论了作为测验质量指标的稳定性、自洽性和可推广性对命题的诉求及具体的实施策略与方法。

客观性测验质量分析方法

客观性测验是指完全采用客观性试题的测验。所谓客观性试题,是指正确答案及表达形式简短且唯一、评分客观的一类试题,它主要包括选择题、是非题和填空题。这类试题的优点在于容量大覆盖面广、测验的可靠性和有效性较高,评卷速度快,更主要的是评分客观,因而被称之为客观性试题。 计算客观性试题的难度、区分度、信度和效度,其方法有很多种。

测验质量评估指标之一——信度及其估计式综述

测验理论的中心问题之一就是如何编制出高质量的测验来,测验的信度是评价测验质量的重要指标之一。国内有关信度的文章或巳出版的有关测验的书籍中对信度的叙述大多是叙述性的。本文试图基于这些叙述性的定义给出严格的数学或统计学上的定义,并对信度系数的一系列估计公式给予证明,尤其还从变异源的角度给出信度的方差分析计算法。

基于Rasch模型对九年级数学能力测验进行质量分析

使用Rasch模型分析软件WINSTEPS对九年级数学能力测验进行质量分析,通过怀特图(Wright Map)了解该测验的整体情况,包括题目难度,学生能力水平;通过单维性检验、项目拟合度、气泡图等反映题目质量的高低。研究结果表明:① 该测验基本符合其测量目标。能较好地区分出学生能力水平和题目难度。② 题目较简单,学生能力水平范围大于题目难度分布,应增加部分高难度题目。③ 存在个别题目与模型预期的结果不一致,需进一步分析其内容与答题状况。研究所分析的九年级数学能力测验总体上能够准确地进行参数估计,是一套质量较高的测验,该测验基本符合其测量目标。

水文测船悬杆测验设备技术改造

针对黄河下游悬杆测验设备落后的局面,对绞车进行了部分改造,并研制了一套适合于测船安装的HCX-1型直读式流速水深计数器,取得了较好的效果。

测验预测的价值

测验作为评价和预测的主要工具之一,广泛运用于各级各类学校,但测验作为预测手段,其价值究竟如何?这个问题并没有引起人们深入思考,特别是许多教育工作者对此问题缺乏正确认识,从而影响了测验预测作用的发挥,进而妨碍人才选拔培养的科学化进程。本文试图从预测的实质,测验对个体预测的可能性,测验预测的准确性,测验预测同其他预测的比较等几方面来论述测验预测的价值问题。

从心理测验的本质看心理测验潜在的问题

本文从心理测验的本质特征的间接性、相对性、定量化、代表性入手,引中出心里测验潜在的四个基本问题:心理特质的测量方法问题;心理测量的行为组样问题;测量量表的单位问题;心理测验的误差问题。在对这些问题的探讨分析的基础上,笔者认为:只有编制和使用心理测验的人员都谨慎对待,正确使用心理测验这一心理评估工具,才能使发挥出它应有的益处。

基于BP神经网络的认知诊断评估分类准确率影响因素分析

BP神经网络是目前应用最广泛的人工神经网络模型之一,在分类和识别上表现出良好的特性,因此被研究者用于认知诊断评估以对被试进行诊断分类。通过模拟研究,考查属性个数、属性层级关系、测验长度、题目质量、测试样本量5个因素对BP神经网络在认知诊断中分类准确性的影响。结果表明:1)基于BP神经网络的认知诊断分类准确率不依赖于测试样本量;2)题目质量和测验长度对BP神经网络的诊断准确率有显著的积极影响;3)属性个数对BP神经网络的分类准确率有消极影响;4)题目质量一定程度上会影响BP诊断方法在不同属性层级结构上的分类准确率。

一种新的信度估计

应用相关系数的信息并结合重排不等式 ,引入了一个新的信度系数 ζ ,并证明了 ζ≥α且在某些情况下 ,ζ可以弥补α系数、β系数及γ系数的不足 ,有时 ζ比λ2

认知诊断模型题目功能差异检验方法的健壮性比较

在认知诊断模型中进行题目功能差异(DIF)的检测,目的在于保证测验的质量与效果。在以往研究的基础上,本研究重点探索在CDMs框架下,MH、LR、CSIBTEST、WObs、WSw、WXPD 6种DIF检测方法在Q矩阵是否正确设定以及有关DIF影响因素等条件下的表现。结果表明:在Q矩阵正确设定时,WObs、WSw和WXPD统计量表现要好于MH、LR和CSIBTEST方法;在Q矩阵错误设定时,6种方法都会出现Ⅰ类错误率膨胀和统计检验力较低的现象。相对而言,MH、LR和CSIBTEST方法的表现比较稳定,WObs、WSw和WXPD统计量的表现变化较大,WObs、WSw和WXPD统计量的Ⅰ类错误率和统计检验力的结果依然好于MH、LR、CSIBTEST方法。

Explanatory System of Support Vector Regression and Its Application in QSPR of Surfactants

In order to solve the problem of poor interpretability of support vector re- gression （SVR） applied in quantitative structure-property relationship （QSPR）, a com- plete set of explanatory system for SVR was established based on F-test, The nov- el explanatory system includes significance tests of model and single-descriptor im- portance, single-descriptor effect and sensitivity analysis, and significance tests of interaction between two descriptors, etc. The results of example indicated that the explanatory results of the new system were consistent well with those of stepwise linear regression model and quadratic polynomial stepwise regression model. The explanatory SVR model will play an important role in regression analysis such as QSPR.

Development and Challenge of HIV/AIDS Testing Laboratory Network and Quality Assurance System in China

This paper describes the development and challenge of HIV/AIDS testing laboratory network and quality assurance system in China. At present,the HIV/AIDS testing laboratories includes three classes,the National AIDS Reference Laboratory,HIV/AIDS confirmatory laboratories and HIV/AIDS screening laboratories. All of them are accredited by the health authorities,and each class of laboratories take charge of their function strictly according to the "National Management of HIV/AIDS Detection (2006)". A complete quality assurance and quality control system for HIV/AIDS testing has been developed,which includes technical training,strict laboratory monitoring and approval,examination or proficiency testing on HIV/AIDS detection,and quality evaluation and supervision of HIV/AIDS diagnostic kits. Besides conduct the routine anti-HIV antibody test,more and more laboratories began to conduct other tests,such as CD4+ T lymphocyte cell counting,HIV viral load,HIV DNA PCR,genotyping,drug resistance,and HIV-1 recent infection test. The primary challenges faced by the HIV/AIDS testing laboratory network are in the areas of laboratory management and quality control. For example,the provincial PT program is inefficient,the internal quality control is conducted perfunctorily,personnel training can not met the needs of the workplace,which need to be improved.

Application of QUAL2K for Water Quality Modeling of River Ghataprabha （India）

River Ghataprabha, during its course through Belgaum district in Karnataka state （India）, receives untreated domestic waste from Gokak town and other neighboring villages situated on the bank of the river. The present study involves the application of water quality model QUAL2K to predict the water quality of this polluted segment of the river. The model was calibrated and validated for biochemical oxygen demand （BOD）, dissolved oxygen （DO） and total nitrogen （TN） in pre-monsoon season. Data for calibration and validation were obtained after the field and laboratory measurements. The performance of the model was evaluated using statistics based on standard errors （SE） and mean multiplicative errors （MME）. The model represented the field data quite well with some exceptions. In spite of some differences between the measured and simulated data sets at some points, the calibration and validation results are acceptable especially for the developing countries where the financial resources are often limited for frequent monitoring campaigns and higher accuracy data analysis.

Digital core approach to the effects of clay on the electrical properties of saturated rocks using lattice gas automation

Clay has a significant influence on the relationship between resistivity index I and water saturation Sw （i.e, I-Sw relationship） of reservoir rocks because it complicates the current paths of these rocks. It is difficult to reveal the physical mechanisms of these clay effects on the conductivities of various rocks by physical laboratory measurements because the pore structure, micro distribution and content of clay inside a rock can not be observed and controlled during the experiments. We present a digital rock approach to study these clay effects on the electrical transport properties of reservoir rocks at pore scale using lattice gas automation （LGA） method. The digital rock samples are constructed with the information of grain size distribution from SEM images of reservoir rocks. The LGA is then applied on these digital rocks fully saturated with fluids to simulate the electrical transport properties for revealing the effects of volume and distribution patterns of clay on the non-Archie behaviors of the I-Sw relationship. The very good agreement between the simulated results and the laboratory measurements clearly demonstrates the validity of the LGA in numerical research of rock physics. Based on these studies, a new model has been developed for quantitatively describing the relationship between the saturation exponent and the volume of clay （Vsh）. This development may improve the evaluation for the fluid saturations in reservoir rocks.

Validation for the Determination of Extractable Metals in Ashes from Biomass Incinerators by ICP-OES

Biomass ashes contain valuable elements for plant growth, but also often high amounts of harmful heavy metals which limit their reuse in forests and on grassland. For monitoring metal concentrations, a fast and reliable method allowing the quantitative determination even at trace levels is mandatory. Therefore an analytical method consisting of an acidic microwave assisted digestion prior to ICP-OES measurement was optimized. The elements of interest were AI, As, B, Ba, Cd, Co, Cr, Cu, Fe, Mg, Mn, Na, Ni, Pb, Sb, St, Ti, V, and Zn. A validation including the following parameters was performed for each analyte： limit of detection, limit of quantification, recovery by spiking experiments, accuracy by analyzing a certified reference material, reproducibility （wihtin-24 hours, 4 and 7 days）, linearity, and uncertainty of measurement. Two standards series were used for calibration - one with 1 M HNO3 and one with additionally 2 g/L Mg（NOD2 to investigate the elimination or decrease of possible matrix effects. Both calibration methods showed very good recoveries. The method optimized allows the determination of the relevant elements covered by the recommendation of the Austrian ministry for agriculture and represents thus an appropriate tool for monitoring the metal contents in biomass ashes.

Equivalent materials simulation experimental study on bed separations developing and mining subsidence in constant humidity and constant temperature conditions

A new experiment was made on the developing of bed separations and mining subsidence from Tangshan T2192 working face by equivalent materials simulation.The overburden deformation and the developing of bed separations with working face advanc- ing was simulated by a new model.The results show that the maximum value of bed separations moved forward gradually along with the working face advancing;the maxi- mum value of bed separations is 0.31～0.50 times of mining thickness.The key strata have a great influence upon surface subsidence during the overburden movement process.The mechanics parameters of new experiment are fitted with results in fields perfectly.

The research of the evaluation system for the sealability of hydraulic supports and jacks＇ seals

In order to enhance the sealing quality and assemble efficiency of hydraulic supports, the evaluation system for the sealability of the hydraulic support and jack＇s seals was established through the testing and experimenting technology in respects, such as seals＇ dimensions, reasonable amounts of compression, sealability, life, resistance to pressure, etc. Through life detecting test of the seal, found the longest life seal ring under the same conditions, and through the reciprocating test of the hydraulic support, found the most appropriate amount of interference between the groove and the seal ring, thus, to decrease the leakage and extend the life span of the hydraulic support.

Developments in the understanding of gas–solid contact efficiency in the circulating fluidized bed riser reactor:A review

In the last several decades, circulating fluidized bed reactors have been studied in many aspects including hydrodynamics, heat and mass transfer and gas–solid two phase contacting. However, despite the abundance of review papers on hydrodynamics, there is no summary paper on gas–solid contact efficiency to date, especially on high density circulating fluidized beds(CFBs). This paper gives an introduction to, and a review of the measurement of contact efficiency in circulating fluidized bed riser. Firstly, the popular testing method of contact efficiency including the method of heating transfer experiment and hot model reaction are discussed, then previous published papers are reviewed based on the discussed methods. Some key results of the experimental work are described and discussed. Gas–solid contact efficiency is affected by the operating conditions as well as the particle size distribution. The result of the contact efficiency shows that the CFB riser is far away from an ideal plug flow reactor due to the characteristics of hydrodynamics in the riser. Lacunae in the available literature have been delineated and recommendations have been made for further work.

Mechanical Characteristics of Chemically Degraded Surface Layers of Wood

The aim of this research was to find out whether the effect of chemical corrosion changes mechanical characteristics of surface layers of wooden construction elements. Degradation of the surface layers of wood was caused by chemical reactions of the basic substances of wood mass with compounds contained in antifire coatings. Fire retardants containing corrosive substances were often and repeatedly used in the Czech Republic on many wooden building constructions. This process of chemical corrosion is in practise called as ＂surface defibering of wood＂. This contribution presents standard and special experimental methods used for measuring the selected mechanical characteristics （compression strength, tension strength, bending strength, hardness and impact resistance） in the damaged surface layer of wooden construction elements. The material for experimental measuring was a construction element removed from a historical roof （ca 150 years old）. Mechanical characteristics of the surface layer of the defibered element were compared with the values measured in the deeper subsurface layer of non-damaged wood. The results of the experiments proved loss of cohesive strength and decrease of mechanical characteristics of wood only in a thin surface layer.