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1.
Gwowen Shieh 《Journal of Experimental Education》2019,87(2):238-259
The analysis of covariance (ANCOVA) is a useful statistical procedure that incorporates covariate features into the adjustment of treatment effects. The consequences of omitted prognostic covariates on the statistical inferences of ANCOVA are well documented in the literature. However, the corresponding influence on sample-size calculations for precise interval estimation has not been fully evaluated. This article aims to explicate the deficiency of approximate methods for ignoring the stochastic nature of covariate variables and to present exact approaches for precise interval estimation of treatment contrasts under the assumption that the covariate variables have a joint multinormal distribution. The desired precision of a confidence interval is assessed with respect to the control of expected half-width and to the assurance probability of interval half-width within a designated value. Numerical appraisals show that the suggested approaches outperform the approximate formulas for the two precision considerations. 相似文献
2.
Gwowen Shieh 《Journal of Experimental Education》2015,83(2):203-217
Analysis of variance is one of the most frequently used statistical analyses in the behavioral, educational, and social sciences, and special attention has been paid to the selection and use of an appropriate effect size measure of association in analysis of variance. This article presents the sample size procedures for precise interval estimation of eta-squared and partial eta-squared in fixed-effects analysis of variance designs. The desired precision of a confidence interval is assessed with respect to (a) the control of expected width and (b) the tolerance probability of interval width within a designated value. In addition, sample size calculations for standardized contrasts of treatment effects and corresponding partial strength of association effect sizes are also considered. 相似文献
3.
Fu-Ming Chen Jason Sheng-Hong Tsai Ying-Ting Liao Shu-Mei Guo Ming-Chung Ho Fu-Zen Shaw Leang-San Shieh 《Journal of The Franklin Institute》2014
An improvement on the transient response of tracking for the sampled-data system based on an improved PD-type iterative learning control (ILC) is proposed in this paper. The developed analog ILC method and the high-gain property tracker design methodology are first combined to significantly reduce learning epochs and overcome the initial condition shift problem and discontinuous reference input in the traditional ILC. Besides, the proposed ILC improves the transient response and decreases the rate of weighting matrices Q to R under the traditional linear quadratic tracker design. First, the off-line observer/Kalman filter identification (OKID) is used to determine the appropriate (low-) order system parameters and state estimator for the physical system with unknown system equation, so that the model-based PD-type ILC can be implemented for practical applications. Then, to improve the transient response and decrease the control effort, the proportional difference type (PD-type) ILC algorithm is combined with the high-gain property linear quadratic tracker (LQT) design to construct the high performance tracker for the model-based sampled-data systems. Furthermore, the discrete-time version high performance tracker design for the unknown stochastic sampled-data system via the iterative learning control method is proposed in this paper based on the Euler method and the digital redesign approach. Finally, some examples are given for illustrating the effectiveness of the proposed method. 相似文献
4.
Jason Sheng-Hong Tsai Meng-Che Wu Leang-San Shieh 《Journal of The Franklin Institute》2005,342(7):852-876
This paper presents a newly developed digital redesign control scheme with a weighted switching strategy and output-reference tracking, for a cascaded analog system with state saturation and external loads. The proposed method improves the generally poor transition response and output deviation caused by state-saturation constraint and external loads. It replaces an existing or theoretically well-designed analog controller with state saturation, by a digital controller with almost identical performance. 相似文献
5.
Jason S.-H. Tsai Chao-Lung Wei Shu-Mei Guo Leang S. Shieh Ce R. Liu 《Journal of The Franklin Institute》2008,345(5):508-535
An evolutionary programming-based adaptive observer is presented in this paper to improve the performance of state estimation of nonlinear time-varying sampled-data systems. Also, this paper presents a novel state-space adaptive tracker together with the proposed observer and estimation schemes for nonlinear time-varying sampled-data systems having actuator failures. For the class of slowly varying nonlinear time-varying systems, the proposed methodology is able to achieve the desired fault detection and performance recovery for the originally well-designed systems, as long as the controller having the high-gain property. For practical implementation, we utilize the advantages of digital redesign methodology to convert a well-designed high-gain analog controller/observer into its corresponding low-gain digital controller/observer. Illustrative examples are given to demonstrate the effectiveness of the proposed method. The developed digitally redesigned adaptive tracker with the proposed observer and estimator is suitable for implementation by using microprocessors. 相似文献
6.
This study compared the perceived importance of and needs for maternal gestational weight information between African American and Caucasian pregnant women. A secondary analysis of data from 113 pregnant women (82 African Americans and 31 Caucasians) attending an inner-city prenatal clinic was conducted for this study. Perceived importance of and needs for information were measured in five areas: (1) nutrition, (2) prenatal vitamins, (3) rest/activity balance, (4) exercise, and (5) appropriate weight gain. African American women demonstrated significantly higher perceived importance of and needs for information on rest/activity balance and appropriate weight gain than Caucasian women. Exercise information was rated lower in importance but was most needed by both African American and Caucasian women. Education programs about maternal gestational weight need to be cognizant of ethnic women's needs. 相似文献
7.
This study investigates the attitudes of a group of low‐status women towards computers through a deliberately designed computer training programme. Four aspects of the women’s attitudes were examined, including computer anxiety, confidence, liking and usefulness. Data sources consist of pre‐ and post‐surveys and interviews with the participants. The results show that the participants’ attitudes towards computers improved greatly after attending the training course, especially in terms of the aspect of anxiety. It was also found that the instructor’s patience, repeated step‐by‐step demonstrations, detailed notes presented with screen‐image snapshots, stand‐by tutors and a friendly learning environment were the main elements that effectively helped the learners increase their positive feelings towards learning to use computers. The study reveals that once women have opportunities to use computers and once they are adequately instructed, the majority will be connected to the digital world in no time. 相似文献
8.
Jackie Shieh 《Cataloging & classification quarterly》2020,58(3-4):418-427
AbstractIn 2015, the PCC Task Group on URIs in MARC was tasked to identify and address linked data identifiers deployment in the current MARC format. By way of a pilot test, a survey, MARC Discussion papers, Proposals, etc., the Task Group initiated and introduced changes to MARC encoding. The Task Group succeeded in laying the ground work for preparing library data transition from MARC data to a linked data, RDF environment. 相似文献
9.
Linbo Xie Leang-San Shieh Jason Sheng-Hong Tsai Shu-Mei Guo Alex Christian Dunn 《Journal of The Franklin Institute》2017,354(14):5797-5812
The discretization of the analog Smith predictor by using the prediction-based state-matching digital redesign method for systems with various input time delays was recently investigated in the literature. This paper presents an alternative Chebyshev quadrature state-matching digital redesign method for discretization of the analog Smith predictor for systems with a long input time delay. In order to implement the digitally redesigned Smith predictor by utilizing the output-feedback of the plant, an ideal state reconstructor for the long input-delayed plant is established. The long dead time of interest is an integer plus a fractional input delay. An illustrative example is given to demonstrate the effective of the proposed approach. 相似文献
10.
Design procedures are proposed for model conversion and digital redesign of a singular system, which is controllable at finite and impulsive modes. In order to attain a standard regular problem, we use some techniques to decompose the singular system into a reduced-order regular subsystem and a nondynamic subsystem. As a result, some well-known design methodologies for a regular system can be applied to the reduced-order regular subsystem. Finally, we transform the results obtained back to those of the original coordinate system. 相似文献