Real time remaining useful life(RUL) prediction based on condition monitoring is an essential part in condition based maintenance(CBM). In the current methods about the real time RUL prediction of the nonlinear degrad...Real time remaining useful life(RUL) prediction based on condition monitoring is an essential part in condition based maintenance(CBM). In the current methods about the real time RUL prediction of the nonlinear degradation process, the measurement error is not considered and forecasting uncertainty is large. Therefore, an approximate analytical RUL distribution in a closed-form of a nonlinear Wiener based degradation process with measurement errors was proposed. The maximum likelihood estimation approach was used to estimate the unknown fixed parameters in the proposed model. When the newly observed data are available, the random parameter is updated by the Bayesian method to make the estimation adapt to the item's individual characteristic and reduce the uncertainty of the estimation. The simulation results show that considering measurement errors in the degradation process can significantly improve the accuracy of real time RUL prediction.展开更多
In view of the major defect of the traditionalteacher correction,this paper introduces a new ap-proach to error correction—group error correction,inwhich learners’ role in learning language is greatly in-creased.Gro...In view of the major defect of the traditionalteacher correction,this paper introduces a new ap-proach to error correction—group error correction,inwhich learners’ role in learning language is greatly in-creased.Group error correction can be used to correcterrors in students’ oral work,group work and writtenwork,both in class and after class.Half a year’spractice of group error correction shows that it helpsincrease learner involvement in the teaching and learn-ing process,stimulate learner motivation in learningthe foreign language,raise the learners’ awareness oferrors,facilitate learners’ learning of the foreign lan-guage,relieve the teacher’s burden,and helps theteacher make better teaching plans.Error correction is an enormously complex pro-cess(Ellis,1994,p585).As for which is the most ef-fective method to correct errors,researchers havenot reached an agreement.Therefore more effortsneed to be made in this field.展开更多
基金Projects(51475462,61374138,61370031)supported by the National Natural Science Foundation of China
文摘Real time remaining useful life(RUL) prediction based on condition monitoring is an essential part in condition based maintenance(CBM). In the current methods about the real time RUL prediction of the nonlinear degradation process, the measurement error is not considered and forecasting uncertainty is large. Therefore, an approximate analytical RUL distribution in a closed-form of a nonlinear Wiener based degradation process with measurement errors was proposed. The maximum likelihood estimation approach was used to estimate the unknown fixed parameters in the proposed model. When the newly observed data are available, the random parameter is updated by the Bayesian method to make the estimation adapt to the item's individual characteristic and reduce the uncertainty of the estimation. The simulation results show that considering measurement errors in the degradation process can significantly improve the accuracy of real time RUL prediction.
文摘In view of the major defect of the traditionalteacher correction,this paper introduces a new ap-proach to error correction—group error correction,inwhich learners’ role in learning language is greatly in-creased.Group error correction can be used to correcterrors in students’ oral work,group work and writtenwork,both in class and after class.Half a year’spractice of group error correction shows that it helpsincrease learner involvement in the teaching and learn-ing process,stimulate learner motivation in learningthe foreign language,raise the learners’ awareness oferrors,facilitate learners’ learning of the foreign lan-guage,relieve the teacher’s burden,and helps theteacher make better teaching plans.Error correction is an enormously complex pro-cess(Ellis,1994,p585).As for which is the most ef-fective method to correct errors,researchers havenot reached an agreement.Therefore more effortsneed to be made in this field.
