Particle filtering （PF） is being applied successfully in nonlinear and/or non-Gaussian system failure prognosis. However, for failure prediction of many complex systems whose dynamic state evolution models involve t...Particle filtering （PF） is being applied successfully in nonlinear and/or non-Gaussian system failure prognosis. However, for failure prediction of many complex systems whose dynamic state evolution models involve time-varying parameters, the tradi- tional PF-based prognosis framework will probably generate serious deviations in results since it implements prediction through iterative calculation using the state models. To address the problem, this paper develops a novel integrated PF-LSSVR frame- work based on PF and least squares support vector regression （LSSVR） for nonlinear system failure prognosis. This approach employs LSSVR for long-term observation series prediction and applies PF-based dual estimation to collaboratively estimate the values of system states and parameters of the corresponding future time instances. Meantime, the propagation of prediction un- certainty is emphatically taken into account. Therefore, PF-LSSVR avoids over-dependency on system state models in prediction phase. With a two-sided failure definition, the probability distribution of system remaining useful life （RUL） is accessed and the corresponding methods of calculating performance evaluation metrics are put forward. The PF-LSSVR framework is applied to a three-vessel water tank system failure prognosis and it has much higher prediction accuracy and confidence level than traditional PF-based framework.展开更多
Chronic heart failure（CHF）remains a leading cause of morbidity and mortality.In the current study,we aimed to evaluate the predictive value of circulating fhrombospondin-2（TSP-2）for cumulative survival in patients...Chronic heart failure（CHF）remains a leading cause of morbidity and mortality.In the current study,we aimed to evaluate the predictive value of circulating fhrombospondin-2（TSP-2）for cumulative survival in patients with ischemic CHF due to coronary artery disease（CAD）.The results showed that during a median follow-up of2.18 years,21 participants died and 106 subjects were hospitalized repeatedly.The median circulating levels of TSP-2 in patients who survived and those who died were 0.63 ng/mL（95%CI=0.55-0.64 ng/mL）and 1.03 ng/mL（95%CI=0.97-1.07 ng/mL）（P〈0.001）.Circulating TSP-2 independently predicted all-cause mortality（OR=1.27;95%CI=1.08-1.59;P=0.002）,CHF-related death（OR=1.16;95%CI=1.02-1.50;P〈0.001）,and also CHF-related rehospitalization（OR=1.12;95%CI=1.07-1.25;P〈0.001）.In conclusion,among CAD patients with symptomatic CHF,increased circulating TSP-2 is correlated with increased 3-year CHF-related death,all-cause mortality,and risk for recurrent hospitalization.展开更多
Objectives To study wheth- er change of BNP levels reflect the change of cardiac function and to investigate the short - term prognostic potential of BNP and QOL in patients with CHF. Methods 96 consecutive patients a...Objectives To study wheth- er change of BNP levels reflect the change of cardiac function and to investigate the short - term prognostic potential of BNP and QOL in patients with CHF. Methods 96 consecutive patients admittedwith CHF between September 2002 and January 2003 were stud- ied , upon entry the study, BNP levels were measured, Patients administered the disease - specificquality of life questionnaire Minnesota living with heart failure questionnaire (LiHFe) within 1 day. BNP levels and administering LiHFe were repeated three months later. Results BNP levels were increased proportional to the severity of cardiac function. Physical domain and total score of LiHFe were significantly correlated to the severity of CHF ( p < 0. 05 ). BNP levels were de- creased in improving group(p =0. 032) . In deteriora- ting group BNP levels increased (P = 0. 043 ) . Kaplan - meier analysis according to BNP level cutoff point 150 ng/1, the life curve of higher BNP level group was significantly lower than the lower group ( p = 0. 001 ) . In univariate logistic regression, NYHA class, BNP, LVEF, LVEDD, heart size, total score of LiHFe, phys- ical domain of LiHFe and the emotional domain of LiH- Fe were all significant prognostic factors of CHF ( p < 0. 05 for all). While in multiple regression, only BNP level( p = 0. 036) and the emotional domain of LiHFe ( p = 0. 025 ) were independent prognostic factors. Conclusions Change of BNP reflects the treatment efficacy of CHF. BNP and QOL are the two major short - time prognostic factors of the chronic heart failure patients.展开更多
基金Aeronautical Science Foundation of China (20100751010, 2010ZD11007)
文摘Particle filtering （PF） is being applied successfully in nonlinear and/or non-Gaussian system failure prognosis. However, for failure prediction of many complex systems whose dynamic state evolution models involve time-varying parameters, the tradi- tional PF-based prognosis framework will probably generate serious deviations in results since it implements prediction through iterative calculation using the state models. To address the problem, this paper develops a novel integrated PF-LSSVR frame- work based on PF and least squares support vector regression （LSSVR） for nonlinear system failure prognosis. This approach employs LSSVR for long-term observation series prediction and applies PF-based dual estimation to collaboratively estimate the values of system states and parameters of the corresponding future time instances. Meantime, the propagation of prediction un- certainty is emphatically taken into account. Therefore, PF-LSSVR avoids over-dependency on system state models in prediction phase. With a two-sided failure definition, the probability distribution of system remaining useful life （RUL） is accessed and the corresponding methods of calculating performance evaluation metrics are put forward. The PF-LSSVR framework is applied to a three-vessel water tank system failure prognosis and it has much higher prediction accuracy and confidence level than traditional PF-based framework.
文摘Chronic heart failure（CHF）remains a leading cause of morbidity and mortality.In the current study,we aimed to evaluate the predictive value of circulating fhrombospondin-2（TSP-2）for cumulative survival in patients with ischemic CHF due to coronary artery disease（CAD）.The results showed that during a median follow-up of2.18 years,21 participants died and 106 subjects were hospitalized repeatedly.The median circulating levels of TSP-2 in patients who survived and those who died were 0.63 ng/mL（95%CI=0.55-0.64 ng/mL）and 1.03 ng/mL（95%CI=0.97-1.07 ng/mL）（P〈0.001）.Circulating TSP-2 independently predicted all-cause mortality（OR=1.27;95%CI=1.08-1.59;P=0.002）,CHF-related death（OR=1.16;95%CI=1.02-1.50;P〈0.001）,and also CHF-related rehospitalization（OR=1.12;95%CI=1.07-1.25;P〈0.001）.In conclusion,among CAD patients with symptomatic CHF,increased circulating TSP-2 is correlated with increased 3-year CHF-related death,all-cause mortality,and risk for recurrent hospitalization.
文摘Objectives To study wheth- er change of BNP levels reflect the change of cardiac function and to investigate the short - term prognostic potential of BNP and QOL in patients with CHF. Methods 96 consecutive patients admittedwith CHF between September 2002 and January 2003 were stud- ied , upon entry the study, BNP levels were measured, Patients administered the disease - specificquality of life questionnaire Minnesota living with heart failure questionnaire (LiHFe) within 1 day. BNP levels and administering LiHFe were repeated three months later. Results BNP levels were increased proportional to the severity of cardiac function. Physical domain and total score of LiHFe were significantly correlated to the severity of CHF ( p < 0. 05 ). BNP levels were de- creased in improving group(p =0. 032) . In deteriora- ting group BNP levels increased (P = 0. 043 ) . Kaplan - meier analysis according to BNP level cutoff point 150 ng/1, the life curve of higher BNP level group was significantly lower than the lower group ( p = 0. 001 ) . In univariate logistic regression, NYHA class, BNP, LVEF, LVEDD, heart size, total score of LiHFe, phys- ical domain of LiHFe and the emotional domain of LiH- Fe were all significant prognostic factors of CHF ( p < 0. 05 for all). While in multiple regression, only BNP level( p = 0. 036) and the emotional domain of LiHFe ( p = 0. 025 ) were independent prognostic factors. Conclusions Change of BNP reflects the treatment efficacy of CHF. BNP and QOL are the two major short - time prognostic factors of the chronic heart failure patients.
