An an alytical model based on linear decreasi ng leveli ng scheme was proposed to inv estigate the longitu din ally profiled plate leveling process.Considering the variable cross-sectional thickness of longitudinally ...An an alytical model based on linear decreasi ng leveli ng scheme was proposed to inv estigate the longitu din ally profiled plate leveling process.Considering the variable cross-sectional thickness of longitudinally profiled plate and the dynamic reductions in leveling rolls,the reduction models of upper and lower rolls,the leveling force model and the leveling moment model were established,respectively,based on linear decreasing leveling scheme.Moreover,the finite element model of longitudinally profiled plate leveling process was established based on ABAQUS.Then,the total displacements of upper and lower rolls,the leveling force and the stress distribution of longifudinally profiled plate in the leveling process were calculated.To verify the validity of the proposed models,calculated leveling forces were compared with the measured values,and very good agreements are found.Calculated results show that linear decreasing leveling scheme is suitable for leveling longitudinally profiled plate.展开更多
Longitudinal data often arise when subjects are followed over a period of time, and in many situations, there may exist informative observation times and a dependent terminal event such as death that stops the follow-...Longitudinal data often arise when subjects are followed over a period of time, and in many situations, there may exist informative observation times and a dependent terminal event such as death that stops the follow-up. In this article, we propose joint modeling and analysis of longitudinal data with possibly informative observation times and a dependent terminal event in which a common subject-specific latent variable is used to characterize the correlations. A borrow-strength estimation procedure is developed for parameter estimation, and both large-sample and finite^sample properties of the proposed estimators are established. In addition, some goodness-of-fit methods for assessing the adequacy of the model are provided. An application to a bladder cancer study is illustrated.展开更多
基金Key R&D Program of China(No.20I7YFB0306404)Natural Science Foundation of Hebei Province(No.E2016203179)Postdoctoral Science Foundation of China(No.2016M590211).
文摘An an alytical model based on linear decreasi ng leveli ng scheme was proposed to inv estigate the longitu din ally profiled plate leveling process.Considering the variable cross-sectional thickness of longitudinally profiled plate and the dynamic reductions in leveling rolls,the reduction models of upper and lower rolls,the leveling force model and the leveling moment model were established,respectively,based on linear decreasing leveling scheme.Moreover,the finite element model of longitudinally profiled plate leveling process was established based on ABAQUS.Then,the total displacements of upper and lower rolls,the leveling force and the stress distribution of longifudinally profiled plate in the leveling process were calculated.To verify the validity of the proposed models,calculated leveling forces were compared with the measured values,and very good agreements are found.Calculated results show that linear decreasing leveling scheme is suitable for leveling longitudinally profiled plate.
基金Supported by the National Natural Science Foundation of China Grants(No.11231010 and 11171330)Key Laboratory of RCSDS,CAS(No.2008DP173182)
文摘Longitudinal data often arise when subjects are followed over a period of time, and in many situations, there may exist informative observation times and a dependent terminal event such as death that stops the follow-up. In this article, we propose joint modeling and analysis of longitudinal data with possibly informative observation times and a dependent terminal event in which a common subject-specific latent variable is used to characterize the correlations. A borrow-strength estimation procedure is developed for parameter estimation, and both large-sample and finite^sample properties of the proposed estimators are established. In addition, some goodness-of-fit methods for assessing the adequacy of the model are provided. An application to a bladder cancer study is illustrated.
