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1.
At times, the same set of test questions is administered under different measurement conditions that might affect the psychometric properties of the test scores enough to warrant different score conversions for the different conditions. We propose a procedure for assessing the practical equivalence of conversions developed for the same set of test questions but administered under different measurement conditions. This procedure assesses whether the use of separate conversions for each condition has a desirable or undesirable effect. We distinguish effects due to differences in difficulty from effects due to rounding conventions. The proposed procedure provides objective empirical information that assists in deciding to report a common conversion for a set of items or a different conversion for the set of items when the set is administered under different measurement conditions. To illustrate the use of the procedure, we consider the case where a scrambled test form is used along with a base test form. If section order effects are detected between the scrambled and base forms, a decision needs to be made whether to report a single common conversion for both forms or to report separate conversions. 相似文献
2.
本文通过实例详细介绍了在自动测试系统中采用 Visual Basic(VB)开发实时测控软件的方法:米用MDI窗体技术设计软件的用户界面:采用动态链接库(DLL)实现对硬件接口的控制:采肜事件驱动编程实现测试软件功能的扩展.同时对测控软件中的数字滤波、信号波形显示等技术进行了介绍. 相似文献
3.
Several structural equation modeling (SEM) strategies were developed for assessing measurement invariance (MI) across groups relaxing the assumptions of strict MI to partial, approximate, and partial approximate MI. Nonetheless, applied researchers still do not know if and under what conditions these strategies might provide results that allow for valid comparisons across groups in large-scale comparative surveys. We perform a comprehensive Monte Carlo simulation study to assess the conditions under which various SEM methods are appropriate to estimate latent means and path coefficients and their differences across groups. We find that while SEM path coefficients are relatively robust to violations of full MI and can be rather effectively recovered, recovering latent means and their group rankings might be difficult. Our results suggest that, contrary to some previous recommendations, partial invariance may rather effectively recover both path coefficients and latent means even when the majority of items are noninvariant. Although it is more difficult to recover latent means using approximate and partial approximate MI methods, it is possible under specific conditions and using appropriate models. These models also have the advantage of providing accurate standard errors. Alignment is recommended for recovering latent means in cases where there are only a few noninvariant parameters across groups. 相似文献
4.
媒体流传送指标（MDI）反映了IP承载网络的传输损伤对IPTV媒体质量的影响．通过研究RFC4445所述的MDI指标测试方法,创新性的提出了在MDI／DF测试中采用微分法即将测试间隔细分为若干微间隔的方法,并在实现的角度对原算法加以改进．在此基础上给出了基于FPGA的MDI指标测试实现方案及仿真结果．该方法不仅减少了计算因子,而且降低了硬件实现复杂度．该方案已应用于lPTV测试仪中,实际测试效果良好． 相似文献
5.
VAE改性聚氨酯木材胶粘剂的制备及性能研究 总被引：2，自引：0，他引：2
以4，4′-二苯基甲烷二异氰酸酯(MDI)与聚乙烯醇(PVA)胶水的交联反应为基础，制得PU乳液，并用VAE乳液对其进行改性，探讨了PCA、MDI的加入量、VAE乳液与PU乳液混合比例等因素对该胶粘剂性能的影响，制备了一种强度高、适用期长、耐水性能优良的木材用胶粘剂。 相似文献
6.
The alignment method (Asparouhov & Muthén, 2014) is an alternative to multiple-group factor analysis for estimating measurement models and testing for measurement invariance across groups. Simulation studies evaluating the performance of the alignment for estimating measurement models across groups show promising results for continuous indicators. This simulation study builds on previous research by investigating the performance of the alignment method’s measurement models estimates with polytomous indicators under conditions of systematically increasing, partial measurement invariance. We also present an evaluation of the testing procedure, which has not been the focus of previous simulation studies. Results indicate that the alignment adequately recovers parameter estimates under small and moderate amounts of noninvariance, with issues only arising in extreme conditions. In addition, the statistical tests of invariance were fairly conservative, and had less power for items with more extreme skew. We include recommendations for using the alignment method based on these results. 相似文献
7.
To infer longitudinal relationships among latent factors, traditional analyses assume that the measurement model is invariant across measurement occasions. Alternative to placing cross-occasion equality constraints on parameters, approximate measurement invariance (MI) can be analyzed by specifying informative priors on parameter differences between occasions. This study evaluated the estimation of structural coefficients in multiple-indicator autoregressive cross-lagged models under various conditions of approximate MI using Bayesian structural equation modeling. Design factors included factor structures, conditions of non-invariance, sizes of structural coefficients, and sample sizes. Models were analyzed using two sets of small-variance priors on select model parameters. Results showed that autoregressive coefficient estimates were more accurate for the mixed pattern than the decreasing pattern of non-invariance. When a model included cross-loadings, an interaction was found between the cross-lagged estimates and the non-invariance conditions. Implications of findings and future research directions are discussed. 相似文献
8.
GRIZZI Fabio FRANCESCHINI Barbara FIAMENGO Barbara RUSSO Carlo DIOGUARDI Nicola 《Journal of Zhejiang University. Science. B》2007,(4)
Hepatocellular carcinoma(HCC) remains one of the major public health problems throughout the world.Although originally associated with tumorigenic processes,liver angiogenesis has also been observed in the context of different liver in-flammatory,fibrotic,and ischemic conditions.Here we investigate the fractal dimension as a quantitator of non-Euclidean two-dimensional vascular geometry in a series of paired specimens of primary HCC and surrounding non-tumoral tissue,and discuss why this parameter might provide additional information regarding cancer behavior.The application of fractal geometry to the measurement of liver vascularity and the availability of a computer-aided quantitative method can eliminate errors in visual interpretation,and make it possible to obtain closer-to-reality numerals that are compulsory for any measurement process. 相似文献
9.
Grizzi F Franceschini B Fiamengo B Russo C Dioguardi N 《Journal of Zhejiang University. Science. B》2007,8(4):217-220
Hepatocellular carcinoma （HCC） remains one of the major public health problems throughout the world. Although originally associated with tumorigenic processes, liver angiogenesis has also been observed in the context of different liver inflammatory, fibrotic, and ischemic conditions. Here we investigate the fractal dimension as a quantitator of non-Euclidean two-dimensional vascular geometry in a series of paired specimens of primary HCC and surrounding non-tumoral tissue, and discuss why this parameter might provide additional information regarding cancer behavior. The application of fractal geometry to the measurement of liver vascularity and the availability of a computer-aided quantitative method can eliminate errors in visual interpretation, and make it possible to obtain closer-to-reality numerals that are compulsory for any measurement process. 相似文献
10.
Erlina Ronda Jill Adler 《International Journal of Science and Mathematics Education》2017,15(6):1097-1114
In this paper, we propose an analytic tool for describing the mathematics made available to learn in a ‘textbook lesson’. The tool is an adaptation of the Mathematics Discourse in Instruction (MDI) analytic tool that we developed to analyze what is made available to learn in teachers’ lessons. Our motivation to adapt the use of the MDI analytic framework to textbooks is to test the relative robustness of the framework in moving across different pedagogic texts (e.g. video of a lesson, a textbook lesson). Our initial findings suggest it has applicability across pedagogic texts, thus opening possibilities for using a common framework and language in research and in professional development activities involving the written and enacted curricula. 相似文献
11.
Steffen Zitzmann Oliver Lüdtke Alexander Robitzsch Herbert W. Marsh 《Structural equation modeling》2016,23(5):661-679
In many applications of multilevel modeling, group-level (L2) variables for assessing group-level effects are generated by aggregating variables from a lower level (L1). However, the observed group mean might not be a reliable measure of the unobserved true group mean. In this article, we propose a Bayesian approach for estimating a multilevel latent contextual model that corrects for measurement error and sampling error (i.e., sampling only a small number of L1 units from a L2 unit) when estimating group-level effects of aggregated L1 variables. Two simulation studies were conducted to compare the Bayesian approach with the maximum likelihood approach implemented in Mplus. The Bayesian approach showed fewer estimation problems (e.g., inadmissible solutions) and more accurate estimates of the group-level effect than the maximum likelihood approach under problematic conditions (i.e., small number of groups, predictor variable with a small intraclass correlation). An application from educational psychology is used to illustrate the different estimation approaches. 相似文献
12.
从动物化石的含氟量着手 ,分析动物化石在形成体中 ,含氟量在不同环境条件下的变化 ,并以此为依据测定动物化石年龄 相似文献
13.
Leonie V. D. E. Vogelsmeier Jeroen K. Vermunt Eeske van Roekel Kim De Roover 《Structural equation modeling》2019,26(4):557-575
When time-intensive longitudinal data are used to study daily-life dynamics of psychological constructs (e.g., well-being) within persons over time (e.g., by means of experience sampling methodology), the measurement model (MM)—indicating which constructs are measured by which items—can be affected by time- or situation-specific artifacts (e.g., response styles and altered item interpretation). If not captured, these changes might lead to invalid inferences about the constructs. Existing methodology can only test for a priori hypotheses on MM changes, which are often absent or incomplete. Therefore, we present the exploratory method “latent Markov factor analysis” (LMFA), wherein a latent Markov chain captures MM changes by clustering observations per subject into a few states. Specifically, each state gathers validly comparable observations, and state-specific factor analyses reveal what the MMs look like. LMFA performs well in recovering parameters under a wide range of simulated conditions, and its empirical value is illustrated with an example. 相似文献
14.
The Hong Kong Hang Seng index futures is taken as a study object and a method of empirical analysis is adopted in order to verify the validity of the application of the value-at-risk (VaR) method in the risk measurement of the stock index futures market. The results suggest that under normal market conditions it is feasible to apply the VaR method in the measurement of the market risks of stock index futures. The daily VaR value of the stock index futures provides a foreseeable profit and loss of the stock index futures. Financial supervisors can adjust their supervising strategies according to the daily VaR value. The speculators can adjust risk capital reserve rates in the same way. The application of this method in China's stock index futures market requires the solutions to specific problems: the absence of historical data, the difficult confirmation of non-risk interest rates etc. 相似文献
15.
《Parenting, science and practice》2013,13(2):77-104
Objective. The purpose of this investigation was to explore associations between father-child interactions and children's cognitive status in an underrepresented group of low-income, ethnically diverse families. Design. Participants were 65 inner-city fathers and their 24-month-old children (34 boys, 31 girls). Father-child interactions were videotaped for 10 min at home during semistructured free play, and mental scale scores on the Bayley Scales of Infant Development were obtained on children. The quality of father-child interactions was assessed using 14 Likert ratings of fathers (e.g., responsiveness, language quality, and intrusiveness) and 12 of children (e.g., play, participation, emotional regulation, and communication). Results. Factor analyses revealed 2 patterns of engagement in fathers (Responsive-Didactic and Negative-Intrusive) and 3 in children (Playful-Communicative, Social, and Regulated). Thirty-six children scored within normal limits on the MDI and 29 scored in the delayed range. Together, fathers' and children's factor scores explained more than 25% of the variance in children's performance on the MDI. Logistic regressions indicated that fathers with high scores on the Responsive-Didactic factor were nearly 5 times more likely to have children within the normal range on the MDI than were low-scoring fathers. Conclusions. These findings point to the importance of considering fathers' role in early cognitive development, particularly in low-income families in which children begin to exhibit significant declines in their second and third years. Positive father-child interactions appear to obviate cognitive delay. 相似文献
16.
Sarah Depaoli 《Structural equation modeling》2013,20(2):178-203
Parameter recovery was assessed within mixture confirmatory factor analysis across multiple estimator conditions under different simulated levels of mixture class separation. Mixture class separation was defined in the measurement model (through factor loadings) and the structural model (through factor variances). Maximum likelihood (ML) via the EM algorithm was compared to a Markov chain Monte Carlo (MCMC) estimator condition using weak priors and a condition using tight priors. Results indicated that the MCMC weak condition produced the highest bias, particularly with a weak Dirichlet prior for the mixture class proportions. Specifically, the weak Dirichlet prior affected parameter estimates under all mixture class separation conditions, even with moderate and large sample sizes. With little knowledge about parameters, ML/EM should be used over MCMC weak. However, MCMC tight produced the lowest bias under all mixture class separation conditions and should be used if tight and accurate priors can be placed on parameters. 相似文献
17.
A new entry in the testing lexicon is through‐course summative assessment, a system consisting of components administered periodically during the academic year. As defined in the Race to the Top program, these assessments are intended to yield a yearly summative score for accountability purposes. They must provide for both individual and group proficiency estimates and allow for the measurement of growth. They must accommodate students who vary in their patterns of curricular exposure. Because they are meant to provide actionable information to teachers they must be instructionally sensitive, so item‐operating characteristics can be expected to change relative to one another as a function of patterns of curricular exposure. This paper discusses methodology one can draw upon to tackle this ambitious collection of inferences. We consider a modeling framework that consists of an item response theory component and a population component, as in the National Assessment of Educational Progress, and show how performance and growth could be expressed in terms of expected performance on a market basket of tasks. We discuss conditions under which modeling simplifications might be possible and discuss studies that would be needed to fit models, estimate parameters, and evaluate data requirements. 相似文献
18.
Confirmatory factor analytic tests of measurement invariance (MI) require a referent indicator (RI) for model identification. Although the assumption that the RI is perfectly invariant across groups is acknowledged as problematic, the literature provides relatively little guidance for researchers to identify the conditions under which the practice is appropriate. Using simulated data, this study examined the effects of RI selection on both scale- and item-level MI tests. Results indicated that while inappropriate RI selection has little effect on the accuracy of conclusions drawn from scale-level tests of metric invariance, poor RI choice can produce very misleading results for item-level tests. As a result, group comparisons under conditions of partial invariance are highly susceptible to problems associated with poor RI choice. 相似文献
19.
The motivation for this research was to understand under what conditions supply chain cooperation might be feasible and under what circumstances it is not. Whereas previous research focuses on dyads in a supply chain, our research seeks to examine a possible factor that can explain why truly cooperative supply chains involving more than two firms are a rarity among independent firms. This research extends the use of game theory to demonstrate the potential impact of a multiple‐tier supply chain agreement. 相似文献
20.
Effects of pH and Eh on release of nitrogen and phosphorus from sediments of West Lake 总被引：1，自引：0，他引：1
The effects of pH and Eh on release of nitrogen and phosphorus from sediments of West Lake under different conditions were investigated by simulation test. Results showed that the net flux of NH4+-N release from sediments increased with pH, but NO3--N showed negative-going release at all tested pH levels. The net flux of NH4+-N release from sediments was higher under anaerobic or aerobic condition of the overlying water, but only under aerobic condition would net release of NO3--N occur. It was also shown that phosphorus released was mainly in its inorganic form, higher pH and anaerobic conditions of overlying water greatly stimulated release of phosphorus. In situ measurement at several West Lake locations indicated that sediment resuspension induced by boat propeller stimulated nutrients release from sediment into overlying water. 相似文献