排序方式： 共有33条查询结果，搜索用时 312 毫秒
1.
Inferences and conclusions drawn from model fitting analyses are commonly based on a single “best fitting” model. If model selection and inference are carried out using the same data model selection, uncertainty is ignored. We illustrate the Type I error inflation that can result from using the same data for model selection and inference, and we then propose a simple bootstrap-based approach to quantify model selection uncertainty in terms of model selection rates. A selection rate can be interpreted as an estimate of the replication probability of a fitted model. The benefits of bootstrapping model selection uncertainty are demonstrated in growth mixture analyses of data from the National Longitudinal Study of Youth, and a 2-group measurement invariance analysis of the Holzinger–Swineford data. 相似文献
2.
Compared to parametric models, nonparametric and semiparametric approaches to modeling nonlinearity between latent variables have the advantage of recovering global relationships of unknown functional form. Bauer (2005) proposed an indirect application of finite mixtures of structural equation models where latent components are estimated in the service of more flexibly recovering characteristics of the latent aggregate regression function. This article develops and evaluates delta method and parametric bootstrap approaches for obtaining approximate confidence intervals for Bauer's semiparametric approach to modeling latent nonlinear functions. Coverage rates of these approximate point-wise confidence intervals or nonsimultaneous confidence bands are evaluated by Monte Carlo and recommendations for their use are suggested. 相似文献
3.
对熔融指数准确可靠的预报在聚丙烯生产中具有至关重要的作用,它能更有效的指导生产过程,进而提高聚丙烯生产的经济效益。神经网络被用来建立初始的熔融指数预报模型,但是单一的神经网络在结构上具有随机性。通过训练一批预报误差小同时结构差异大的神经网络作为子网络,再将它们组合起来得到bootstrap组合神经网络,基于此建立起了最优熔融指数预报模型。通过对实际聚丙烯生产过程中的历史数据的研究,表明该模型的预报精度高、可靠性强,有望在实际工业中得到广泛应用。 相似文献
4.
构建共享心智模式,提高创新绩效,是企业获得持续竞争优势的关键。以组织学习空间为中介变量,构建共享心智模式对创新绩效作用机制的理论分析框架。在此基础上,使用基于Bootstrap的结构方程模型对已构建的理论分析框架进行实证分析。实证结果表明：共享心智模式对创新绩效的提高具有显著的直接推动作用;组织学习空间在共享心智模式与创新绩效关系间起部分中介作用。实证结论将为进一步通过完善共享心智模式,提高自身紧密度,拓展组织学习知识面,提高组织创新绩效提供理论依据和实践借鉴。 相似文献
5.
丁建立 《洛阳师范学院学报》1996,(2)
系统引导型病毒是在系统引导加载过程中进入系统中，获得对系统的控制权。其传染性强，危害大，难以根除。本文根据系统引导型病毒机理及特征，从防范的角度出发，找到了根治系统引导型病毒的最佳方法。 相似文献
6.
Roy Lowe 《International Journal of Research & Method in Education》2013,36(1):45-52
Abstract This article reports on the findings of an investigation in which 30 secondary schools rated the priority being given to and the likely impact on teaching and learning of a selection of 23 issues currently on the agenda for school improvement. Results are considered for the whole sample, and according to the role of respondents and school context. Schools are giving high priority to the implementation of national policies and school‐generated initiatives directed at improved classroom practice. However, the perceived impact of externally generated change is less than that of change for which school staff feel a sense of ownership. Policies directed at a consideration of resource issues, professional development and salary changes are accorded low priority and are not considered to have a marked impact on teaching and learning. There is a potential for frustration and loss of morale when policies that are thought to be of limited value within schools require time and sometimes extensive consideration. The article's conclusions for policy‐makers are directed at minimising this risk. 相似文献
7.
Victor H. Kelley 《Journal of Experimental Education》2013,81(3):249-250
Marsh and Hau (1996) based the assertion that parsimony is not always desirable when assessing model fit on a particular counterexample drawn from Marsh's previous research. This counterexample is neither general nor valid enough to support such a thesis. More specifically, the counterexample signals an oversight of extant, stochastic models justifying correlated uniquenesses, namely, moving-average and autoregressive moving-average models. Such models provide theoretically plausible motives for a priori specification of error correlations. In fact, when uniquenesses are correlated, stochastic models other than the conventional simplex and quasi-simplex models must be tested before positive identification of the process is possible (Sivo, 1997). In short, exchanging the mechanistic penalties for model complexity for the mechanistic specification of untenable measurement-error covariances offers no solution. Parsimony has not been dismissed based on the argument Marsh and Hau presented concerning longitudinal data. 相似文献
8.
介绍了一种高性能CMOS采样/保持电路,在0.35-μm工艺、3.3-V电源和18-mW功耗下,实现了50-MHz采样频率,输入直到奈奎斯特频率仍能达到10位精度的要求。电路采用全差分结构、底极板采样、栅压自举开关技术、增益自举的折叠共源共栅跨导核心运算放大器和钳制共模电平的电平控制放大器。 相似文献
9.
C. Andersson J. Antelius J. Månsson K. Sund 《Scandinavian Journal of Educational Research》2017,61(2):205-223
This study investigates technical efficiency and productivity for Swedish higher education institutions (HEIs). One identified problem in previous research concerns adjusting efficiency scores for input quality. This problem is avoided using grades from upper-secondary schools. A second problem concerns heterogeneity with respect to subjects and institutions between HEIs. Using the Swedish national resource allocation system, students are weighted according to subject. For research production, a bibliometric index that allows for differences in publication tradition is used. A third problem when using the data envelopment analysis approach is the lack of statistical inference. Bootstrapping is used to approach this problem. The results indicate an average inefficiency of 12% and a productivity increase of around 1.7% per year. 相似文献
10.
基于SMIC 0.18um CMOS工艺设计了一种高速、高精度、高线性度的采样保持电路。采用全差分带增益自举电路的高增益、高带宽运放,以及改进的带衬底电压调整的栅压自举开关,有效增加输入信号带宽并减小采样保持电路的非线性。对设计的电路进行仿真,在输入信号幅值为2VP-P,频率为47.66MHz,采样频率为100MSPS时,采样保持电路建立时间为3.606ns,建立精度达0.004%,有效位数为17.2bit,无杂散动态范围达108.5dB。 相似文献