A new approach is advanced based on wavelet transform in tandem with autoregressive technique. Wavelets and wavelet packets decompose dynamic signal into different bands and pro- vide multiresolution or multiscale vie...A new approach is advanced based on wavelet transform in tandem with autoregressive technique. Wavelets and wavelet packets decompose dynamic signal into different bands and pro- vide multiresolution or multiscale view of signal. Autoregressive technique possesses effective function for short data processing. The approach is abopted to analyse nonstationary vibration sig- nals of mining excavator. The results indicate that nonstationary operating condition can be moni- tored and diagnosed. Transient toothmeshing frequency and rotating speed are measured. Weak vibration signal of defective ball bearing is extracted from strong vibration of gearbox and diag- nosed successfully. This approach is effective for nonstationary condition monitoring and early di- agnosis of latent fault.展开更多
In this paper,a sliding mode observer scheme of sensor fault diagnosis is proposed for a class of time delay nonlinear systems with input uncertainty based on neural network.The sensor fault and the system input uncer...In this paper,a sliding mode observer scheme of sensor fault diagnosis is proposed for a class of time delay nonlinear systems with input uncertainty based on neural network.The sensor fault and the system input uncertainty are assumed to be unknown but bounded.The radial basis function (RBF) neural network is used to approximate the sensor fault.Based on the output of the RBF neural network,the sliding mode observer is presented.Using the Lyapunov method,a criterion for stability is given in terms of matrix inequality.Finally,an example is given for illustrating the availability of the fault diagnosis based on the proposed sliding mode observer.展开更多
Purpose:.To analyze clinical features and main causes of multiple sclerosis-related optic neuritis(MS-ON), providing evidence for the differential diagnosis of MS-ON.Methods: Clinical data were collected from 527 pati...Purpose:.To analyze clinical features and main causes of multiple sclerosis-related optic neuritis(MS-ON), providing evidence for the differential diagnosis of MS-ON.Methods: Clinical data were collected from 527 patients, 123 males and 404 females, diagnosed with MS-ON between June2008 and June 2013. Visual acuity, optometry, visual field,slit-lamp microscopy, indirect ophthalmoscopy(20D), optical coherence tomography(OCT) and magnetic resonance imaging(MRI) were performed. Venous blood was sampled for detection of autoimmune antibodies and Aquaporin(AQP-4).Results:.Fifty nine cases were diagnosed with neuromyelitis optica-related optic neuritis.(NMO-ON),.27 Sjogren's syndrome-related optic neuropathy,.22 tumors,.21 anterior ischemic optic neuropathy, 15 radiation-induced optic neuropathy, 14 optic neuropathy-related infection, 17 genetic eye diseases and 10 open angle glaucoma. Among168 MS-ON patients undergoing optic nerve MRI,90 cases(53.57%) had a lesion < 15 mm in size, 15-30 mm in 76(45.24%) and > 30 mm in two(1.19%).Conclusion:.MS-ON is more commonly misdiagnosed with NMO-ON and Sjogren's syndrome, when compared to optic neuropathy, tumors and ischemic optic neuropathy.展开更多
文摘A new approach is advanced based on wavelet transform in tandem with autoregressive technique. Wavelets and wavelet packets decompose dynamic signal into different bands and pro- vide multiresolution or multiscale view of signal. Autoregressive technique possesses effective function for short data processing. The approach is abopted to analyse nonstationary vibration sig- nals of mining excavator. The results indicate that nonstationary operating condition can be moni- tored and diagnosed. Transient toothmeshing frequency and rotating speed are measured. Weak vibration signal of defective ball bearing is extracted from strong vibration of gearbox and diag- nosed successfully. This approach is effective for nonstationary condition monitoring and early di- agnosis of latent fault.
基金Natural Science Foundation of Jiangsu Province (No.SBK20082815)Aeronautical Science Foundation of China (No.20075152014)
文摘In this paper,a sliding mode observer scheme of sensor fault diagnosis is proposed for a class of time delay nonlinear systems with input uncertainty based on neural network.The sensor fault and the system input uncertainty are assumed to be unknown but bounded.The radial basis function (RBF) neural network is used to approximate the sensor fault.Based on the output of the RBF neural network,the sliding mode observer is presented.Using the Lyapunov method,a criterion for stability is given in terms of matrix inequality.Finally,an example is given for illustrating the availability of the fault diagnosis based on the proposed sliding mode observer.
文摘Purpose:.To analyze clinical features and main causes of multiple sclerosis-related optic neuritis(MS-ON), providing evidence for the differential diagnosis of MS-ON.Methods: Clinical data were collected from 527 patients, 123 males and 404 females, diagnosed with MS-ON between June2008 and June 2013. Visual acuity, optometry, visual field,slit-lamp microscopy, indirect ophthalmoscopy(20D), optical coherence tomography(OCT) and magnetic resonance imaging(MRI) were performed. Venous blood was sampled for detection of autoimmune antibodies and Aquaporin(AQP-4).Results:.Fifty nine cases were diagnosed with neuromyelitis optica-related optic neuritis.(NMO-ON),.27 Sjogren's syndrome-related optic neuropathy,.22 tumors,.21 anterior ischemic optic neuropathy, 15 radiation-induced optic neuropathy, 14 optic neuropathy-related infection, 17 genetic eye diseases and 10 open angle glaucoma. Among168 MS-ON patients undergoing optic nerve MRI,90 cases(53.57%) had a lesion < 15 mm in size, 15-30 mm in 76(45.24%) and > 30 mm in two(1.19%).Conclusion:.MS-ON is more commonly misdiagnosed with NMO-ON and Sjogren's syndrome, when compared to optic neuropathy, tumors and ischemic optic neuropathy.
