The Robustness of the Analysis of Variance and the Tukey WSD Test under Various Patterns of Heterogeneous Variances

The WSD and F tests show the same response when the homogeneous variance assumption is violated. Both are robust when the ns are equal, but may be either seriously conservatively biased or seriously permissively biased when heterogeneous variances are combined with unequal ns. The use of equal ns is recommended for either test. There is no virtue in insisting that the F test be significant prior to conducting the WSD when the alternative to the null is μ_i ≠ μ_j. However, the conservative bias created by this procedure is small when K = 4; as is the permissive bias created by conducting both tests. For uniformly distributed μ’s, the two tests have very similar powers. This condition would not be expected for different arrangements of the μ’s.     

Performance of Bootstrapping Approaches to Model Test Statistics and Parameter Standard Error Estimation in Structural Equation Modeling

Though the common default maximum likelihood estimator used in structural equation modeling is predicated on the assumption of multivariate normality, applied researchers often find themselves with data clearly violating this assumption and without sufficient sample size to utilize distribution-free estimation methods. Fortunately, promising alternatives are being integrated into popular software packages. Bootstrap resampling, which is offered in AMOS (Arbuckle, 1997), is one potential solution for estimating model test statistic p values and parameter standard errors under nonnormal data conditions. This study is an evaluation of the bootstrap method under varied conditions of nonnormality, sample size, model specification, and number of bootstrap samples drawn from the resampling space. Accuracy of the test statistic p values is evaluated in terms of model rejection rates, whereas accuracy of bootstrap standard error estimates takes the form of bias and variability of the standard error estimates themselves.     

Multiple choice and true/false tests: reliability measures and some implications of negative marking

The standard error of measurement usefully provides confidence limits for scores in a given test, but is it possible to quantify the reliability of a test with just a single number that allows comparison of tests of different format? Reliability coefficients do not do this, being dependent on the spread of examinee attainment. Better in this regard is a measure produced by dividing the standard error of measurement by the test's ‘reliability length’, the latter defined as the maximum possible score minus the most probable score obtainable by blind guessing alone. This, however, can be unsatisfactory with negative marking (formula scoring), as shown by data on 13 negatively marked true/false tests. In these the examinees displayed considerable misinformation, which correlated negatively with correct knowledge. Negative marking can improve test reliability by penalizing such misinformation as well as by discouraging guessing. Reliability measures can be based on idealized theoretical models instead of on test data. These do not reflect the qualities of the test items, but can be focused on specific test objectives (e.g. in relation to cut‐off scores) and can be expressed as easily communicated statements even before tests are written.     

Multiplicity Control in Structural Equation Modeling: Incorporating Parameter Dependencies

When structural equation modeling (SEM) analyses are conducted, significance tests for all important model relationships (parameters including factor loadings, covariances, etc.) are typically conducted at a specified nominal Type I error rate (α). Despite the fact that many significance tests are often conducted in SEM, rarely is multiplicity control applied. Cribbie (2000, 2007) demonstrated that without some form of adjustment, the familywise Type I error rate can become severely inflated. Cribbie also confirmed that the popular Bonferroni method was overly conservative due to the correlations among the parameters in the model. The purpose of this study was to compare the Type I error rates and per-parameter power of traditional multiplicity strategies with those of adjusted Bonferroni procedures that incorporate not only the number of tests in a family, but also the degree of correlation between parameters. The adjusted Bonferroni procedures were found to produce per-parameter power rates higher than the original Bonferroni procedure without inflating the familywise error rate.     

An SAS Macro for Implementing the Modified Bollen-Stine Bootstrap for Missing Data: Implementing the Bootstrap Using Existing Structural Equation Modeling Software

The Bollen-Stine bootstrap can be used to correct for standard error and fit statistic bias that occurs in structural equation modeling (SEM) applications due to nonnormal data. The purpose of this article is to demonstrate the use of a custom SAS macro program that can be used to implement the Bollen-Stine bootstrap with existing SEM software. Although this article focuses on missing data, the macro can be used with complete data sets as well. A series of heuristic analyses are presented, along with detailed programming instructions for each of the commercial SEM software packages.     

一类变分不等式问题的三角形有限元方法

主要讨论了一类变分不等式的三角形有限元方法.在区域剖分不要求满足通常的正则性假设下,通过利用新的方法和技巧,得到了与传统有限元相同的最优误差估计结果,从而扩展了有限元的工程应用范围.     

On the fracture resistance of adhesively jointing structures

INTRODUCTION Adhesive bonding technology has been widely applied in modern structures in industries such as automotive, aerospace and in microelectronic device. The core idea of this technology is to bond two similar or dissimilar structure members with a thin continuous interface layer which can provide far better stress transfer across the interface than those traditional point-wise joining technologies such as spot welding, riveting and bolting. Furthermore, the damage tolerance proper…     

基于电压三角形法测量无源一端口等效参数的实验方案分析

同样的实验原理,采用不同的实验参数,可以得到不同的实验准确度。以电压三角形法测量无源一端口等效参数实验为例,通过展开对实验误差的分析,从中得出实验方案的选取策略,得出减小实验误差的有效措施。     

OPTIMAL NUMBER OF OPTIONS: AN INVESTIGATION OF THE ASSUMPTION OF PROPORTIONALITY

One assumption common to all models for determining the optimal number of options per item (e. g., Lord, 1977) is that total testing time is proportional to the number of items and the number of options per item. Therefore, under this assumption given a fixed testing time, the test can be shortened or lengthened by deleting or adding a proportional number of options. The present study examines the validity of this assumption in three tests which were administered with 2, 3, 4, and 5 options per item. The number of items attempted in the first 10 and 15 minutes of the testing session and the time needed to complete the tests were recorded. Thus, the rate of performance for both fixed time and fixed test length was analyzed. A strong and consistently negative relationship between rate of performance and the number of options was detected in all tests. Thus, the empirical results did not support the assumption of proportionality. Furthermore, the data indicated that the method by which options are deleted can play a role in this context. A more realistic assumption of generalized proportionality, proposed by Grier (1976), was supported by the results from a Mathematical Reasoning test, but was only partially supported for a Vocabulary and a Reading Comprehension test.     

The Functioning of Single-Case Randomization Tests With and Without Random Assignment

The authors used Monte Carlo methods to examine the Type I error rates for randomization tests applied to single-case data arising from ABAB designs involving random, systematic, or response-guided assignment of interventions. Six randomization tests were examined (permuting blocks of 1, 2, 3, or 5 observations, and randomly selecting intervention triplets so that each phase has at least 3 or 5 observations). When the design included randomization, the Type I error rate was controlled. When the design was systematic or guided by the absolute value of the slope, the tests permuting blocks tended to be liberal with positive autocorrelation, whereas those based on the random selection of intervention triplets tended to be conservative across levels of autocorrelation.     

一种识别IP电话语音包的新方法

本文是为了解决在互联网上用于实时多媒体通信的RTP包的识别问题。方法是通过SVM识别RTP报头的特征来进行分类。实验表明，这种方法取得了比较好的分类效果。     

The calculation of new and improved WISC-III subtest reliability,uniqueness, and general factor characteristic information through the use of data smoothing procedures

Assessment practitioners are often encouraged to adopt an “intelligent” approach to the interpretation of intelligence tests. A fundamental assumption of the “intelligent testing” philosophy is that psychometric test information (e.g., subtest g loadings) should be considered during the interpretive process. The relevant psychometric information is provided in the form of sample-based estimates. Unfortunately, the accuracy of these estimates, and the subsequent qualitative classification of intelligence subtests (e.g., good, fair, poor), are influenced to an unknown degree by sampling error. The current study demonstrated how data smoothing procedures, procedures commonly used in the development of continuous test norms, can be used to provide better estimates of the reliability, uniqueness, and general factor characteristics for the WISC-III subtests. © 1997 John Wiley & Sons, Inc.     

The Comprehensive Assessment of Rational Thinking

The Nobel Prize in Economics was awarded in 2002 for work on judgment and decision-making tasks that are the operational measures of rational thought in cognitive science. Because assessments of intelligence (and similar tests of cognitive ability) are taken to be the quintessence of good thinking, it might be thought that such measures would serve as proxies for the assessment of rational thought. It is important to understand why such an assumption would be misplaced. It is often not recognized that rationality and intelligence (as traditionally defined) are two different things conceptually and empirically. Distinguishing between rationality and intelligence helps explain how people can be, at the same time, intelligent and irrational. Thus, individual differences in the cognitive skills that underlie rational thinking must be studied in their own right because intelligence tests do not explicitly assess rational thinking. In this article, I describe how my research group has worked to develop the first prototype of a comprehensive test of rational thought (the Comprehensive Assessment of Rational Thinking).     

试论当代美国品格教育理论的局限

品格教育是当代美国学校道德教育的主流形式,它的兴起建立在对形式道德教育批判的基础之上。但是由于对"品格"解释的含混、哲学假设论证的不足、人性假设的保守以及灌输与教导方法的粗糙陈旧,导致品格教育在理论上存在诸多局限。     

基于模糊神经网络的热电联产故障诊断研究

为了在缺少设计参数的条件下,设计一个非线性模型的热电联产故障诊断系统,提出了一种基于模糊神经网络的设计方法。通过分析热电联产控制系统各工作模块的工作过程,建立废热回收蒸汽锅炉、蒸汽集箱、汽吸收式冷凝器等模块工作模型。并采用粒子群优化算法对提出的模糊神经网络进行优化,假设模型和测量误差正常分布且相互独立,对模型置信区间进行了计算。实验测试表明,本文设计的故障检测具有较高的可信度。     

移动电子商务分销模式在泉州旅游产业的应用

移动电子商务分销模式能促进区域旅游产业的升级转型与发展。通过对国内旅游服务提供商应用移动电子商务情况的分析,以及对泉州与厦门旅游产业电子商务应用情况的差距发现,认为泉州旅游产业移动电子商务应用主要存在旅游网站建设水平较低、移动电子商务分销应用程度低、旅游服务提供商与旅游门户网站合作程度低等问题,提出泉州旅游产业移动电子商务可从通信运营商、网络信息平台、会员、旅游产品"套餐"与自助定制、C2B逆向拍卖等角度探索分销模式。     

Do Pictures Make a Difference? A Test of the Hypothesis that Performance in Tests of Phonological Awareness is Eased by the Presence of Pictures

Many educational psychologists now conduct assessments of children's phonological skills. In the context of an outline of some of the issues relating to memory and phonological awareness, this paper explores an assumption underlying a method of assessing phonological awareness. It was assumed by Maclean, Bryant and Bradley (1987) that the presence of pictures in tests of phonological awareness made the tasks easier. This paper describes how that assumption was directly tested. Children aged 5, 6 and 7 years were given two measures of phonological awareness under two conditions: one with pictures, and one without the presence of pictures. Two measures of their memory were also taken. The results suggest that performance in the tests of phonological awareness may be assisted by the presence of pictures. However, although phonological awareness scores were associated with scores from the measures of memory, the evidence of an effect due to pictures was not significantly associated with either short-term or working memory. Suggestions are offered in conclusion that may assist interested educational psychologists develop more practical assessments of phonological awareness.     

Symmetric peace education as advanced by Anatol Pikas — A critique and an analysis

The ideas of symmetric peace and symmetric peace education, developed by Anatol Pikas in the preceding article, are here criticised for their lack of definition; it is also alleged that inadequate explanation is given of how the concepts may be applied — for example, in the case of a strong power oppressing a weak one. In particular, this critique concentrates on Pikas' assumption of who the antagonists are, and on his belief in the value of prepared teaching materials. Brock-Utne argues that the common enemy is the arms race itself and that the inculcation of critical and discriminating attitudes is likely to be more effective than producing teaching packages. Constructive alternative ideas, incorporating some of Pikas' thinking, are offered. These emphasize (1) the importance of joint cultural/education exchange programmes for promoting international understanding at grass-roots level; (2) the need to put one's own house in order before criticising the neighbour's — a reference to Sweden's policies, with which Pikas claims to identify, and to the implications of Norway's membership of NATO for those in that country concerned with building peace; and (3) the desirability of setting up fora where, under the right conditions, a type of symmetric peace education can be pursued.     

GRE over IPSec工作流程探究与应用分析

GRE over IPSec是将GRE封装后的报文又封装到IPSec报文中的一种VPN应用技术,该技术克服了GRE VPN明文传输无加密功能而IPSEC VPN具有加密功能但只能封装在单播报文的缺陷,发挥了GRE和IPSec各自的独特功能,实现了对私网数据单播和组播加密传输,是企业构建In-tranet/Extranet VPN网络实用技术。     

Improving Person-Fit Assessment by Correcting the Ability Estimate and Its Reference Distribution

The standardized log-likelihood of a response vector (l_z) is a popular IRT-based person-fit test statistic for identifying model-misfitting response patterns. Traditional use of l_z is overly conservative in detecting aberrance due to its incorrect assumption regarding its theoretical null distribution. This study proposes a method for improving the accuracy of person-fit analysis using l_z which takes into account test unreliability when estimating the ability and constructs the distribution for each l_z through resampling methods. The Type I error and power (or detection rate) of the proposed method were examined at different test lengths, ability levels, and nominal α levels along with other methods, and power to detect three types of aberrance—cheating, lack of motivation, and speeding—was considered. Results indicate that the proposed method is a viable and promising approach. It has Type I error rates close to the nominal value for most ability levels and reasonably good power.