Shrinkage Estimation Strategies in Generalised Ridge Regression Models: Low/High-Dimension Regime

In this study, we suggest pretest and shrinkage methods based on the generalised ridge regression estimation that is suitable for both multicollinear and high-dimensional problems. We review and develop theoretical results for some of the shrinkage estimators. The relative performance of the shrinkage estimators to some penalty methods is compared and assessed by both simulation and real-data analysis. We show that the suggested methods can be accounted as good competitors to regularisation techniques, by means of a mean squared error of estimation and prediction error. A thorough comparison of pretest and shrinkage estimators based on the maximum likelihood method to the penalty methods. In this paper, we extend the comparison outlined in his work using the least squares method for the generalised ridge regression.     

A Geometrical Interpretation of Collinearity: A Natural Way to Justify Ridge Regression and Its Anomalies

Justifying ridge regression from a geometrical perspective is one of the main contributions of this paper. To the best of our knowledge, this question has not been treated previously. This paper shows that ridge regression is a particular case of raising procedures that provide greater flexibility by transforming the matrix X associated with the model. Thus, raising procedures, based on a geometrical idea of the vectorial space associated with the columns of matrix X , lead naturally to ridge regression and justify the presence of the well-known constant k on the main diagonal of matrix X ^′ X . This paper also analyses and compares different alternatives to raising with respect to collinearity mitigation. The results are illustrated with an empirical application.     

特细砂配制高流动性泵送C55预应力混凝土应用

本文通过试验分析特细砂粒径,不同材质的特细砂的基本物理材性,采用现代混凝土配合比设计理念,研究了特细砂混凝土配合比的设计原则。通过分析砂率含量、用水量、高效外加剂对特细砂高性能混凝土在工作性和力学性能上的影响,确定砂率含量的范围;通过对特细河砂和天然特细山砂混凝土性能的对比试验,结果表明细砂完全可以替代天然中粗砂配制高性能高强度、高流动性泵送混凝土。     

玻璃纤维增强塑料夹砂管初始力学性能检测的研究

由玻璃纤维增强塑料夹砂管的环刚度、刚度等级概念分析了环刚度设计与检测的基本方法,探讨挠曲水平、轴向拉伸强力和环向拉伸强力检测方法,比较分析了各种方法的优缺点与适用范围,对理解及掌握玻璃纤维增强塑料夹砂管初始力学性能的概念及相关检测方法具有一定参考意义。     

富水粉细砂地层隧道综合降水设计与施工技术

本文通过对实例进行分析论述,解决了围岩受施工扰动和水长期浸润后开挖时不稳定问题,保证了隧道结构和施工安全,为同等或类似地质条件下的地下工程研究及施工提供借鉴和参考。     

高职铸造专业实训改进研究与实施

为了提高高职学院铸造专业学生实训效果,通过消失模铸造改进传统木模手工造型,既提高了学生实际动手能力,又使学生掌握了该门先进铸造技术,增强了学生就业竞争能力。     

RIDGE ESTIMATORS FOR PROBIT REGRESSION: WITH AN APPLICATION TO LABOUR MARKET DATA

In this paper we propose ridge regression estimators for probit models since the commonly applied maximum likelihood (ML) method is sensitive to multicollinearity. An extensive Monte Carlo study is conducted where the performance of the ML method and the probit ridge regression (PRR) is investigated when the data are collinear. In the simulation study we evaluate a number of methods of estimating the ridge parameter k that have recently been developed for use in linear regression analysis. The results from the simulation study show that there is at least one group of the estimators of k that regularly has a lower mean squared error than the ML method for all different situations that have been evaluated. Finally, we show the benefit of the new method using the classical Dehejia and Wahba dataset which is based on a labour market experiment.     

花土沟油田化学防砂技术研究与应用

分析了花土沟油田油井出砂特征,并根据花土沟油田地层特点制定了合理的防治措施,采用GFY-DMP低聚物进行了化学防砂现场试验,其恢复产能效果明显,防砂有效期长。     

ERP沙盘模拟课程的应用价值分析

ERP沙盘模拟演练把复杂、抽象的经营管理理论以最直观的方式让学员体验、学习,使得学员在短短几天的时间内模拟企业六年的经营管理的全过程。其完整生动的视觉感受能够有效地激发学员的学习兴趣,增强学习能力。无论是企业高层、中层领导、一般员工还是普通学生,都能通过该课程能加深对企业管理和ERP原理的理解与领悟,提高各自的业务技能,获得最佳的学习体验。     

灌砂法检测路基压实度技术探讨

鉴于灌砂法在路基压实度检测中的广发应用,本文从室内和现场两个角度探讨了灌砂法相关技术问题,为公路工程建设提供参考。