A new integrity metric for navigation systems is proposed based on the measurement domain. Proba-hilistic optimization design offers tools for fault detection by considering the required navigation performance （RNP）...A new integrity metric for navigation systems is proposed based on the measurement domain. Proba-hilistic optimization design offers tools for fault detection by considering the required navigation performance （RNP） parameter and the uncertainty noise. The choice of the proper performance parameter provided the single-valued mapping with the missed detection probability estimates the probability of failure. The desirable characteristics of the residual sensitivity matrix are exploited to increase the efficiency for identifying erroneous observations. The algorithm can be used to support the performance specification and the efficient calculation of the integrity monitoring process. The simulation for non-precision approach （NPA） validates both the viability and the effectiveness of the proposed algorithm.展开更多
This paper presents a new information fusion filter in integrated navigation. The method can improve the fault-tolerant performance and make well fault detection, isolation and reconfiguration of the integrated naviga...This paper presents a new information fusion filter in integrated navigation. The method can improve the fault-tolerant performance and make well fault detection, isolation and reconfiguration of the integrated navigation system exist. Based on three sensors'(strapdown system, GPS receiver, Doppler radar) information fusion, a fault-tolerant navigation system is designed with this information fusion filter and two-ellipsoid overlap test. Simulation results show that the design is efficient with the soft-failure of gyro, accelerator, GPS receiver and Doppler radar.展开更多
Aim To detect sensor failure in control system using a single sensor signal. Methods A neural predictor was designed based on a radial basis function network(RBFN), and the neural predictor learned the sensor sig...Aim To detect sensor failure in control system using a single sensor signal. Methods A neural predictor was designed based on a radial basis function network(RBFN), and the neural predictor learned the sensor signal on line with a hybrid algorithm composed of n means clustering and Kalman filter and then gave the estimation of the sensor signal at the next step. If the difference between the estimation and the actural values of the sensor signal exceeded a threshold, the sensor could be declared to have a failure. The choice of the failure detection threshold depends on the noise variance and the possible prediction error of neural predictor. Results and Conclusion\ The computer simulation results show the proposed method can detect sensor failure correctly for a gyro in an automotive engine.展开更多
Modern automobile testing systems are complexly computerized measure and control systems, and used in automobile vehicle design centers and assembly plants. Their performance is critical but difficult to be monitored ...Modern automobile testing systems are complexly computerized measure and control systems, and used in automobile vehicle design centers and assembly plants. Their performance is critical but difficult to be monitored efficiently and in real time. This paper introduces an Internet based remote monitoring system for automobile testing systems, and the design and the implementation using Web database and Socket techniques.展开更多
A new passive method for automatic dis-covery and bcation of network failure is proposed. This method employs a passive measurement to collect infonmtion and events from network traffic, and em-ploys a rrodel-based re...A new passive method for automatic dis-covery and bcation of network failure is proposed. This method employs a passive measurement to collect infonmtion and events from network traffic, and em-ploys a rrodel-based reasoning system to detect and locate network faults. Measurement points are de-ployed in a backbone network to capture the traffic and then evaluate the Quality of Service （QoS） metrics of end-to-end IP conversations. A muting rrodel is al-so established for the observed network to simulate the attributes and activities of reuters and links. This muting model also deduces the muting path for each IP conversation, and thus the QoS metrics of IP con-versations are mapped into the metrics of paths. With the inforrmtion of shared links of overlapping paths and network torrography technique, the QoS metrics of links can also be estimated, and the poorly rated links are picked out as failure points. This method is imple-mented in a tool named FaultMan, which is deployed in a campus network. Test results have shown its availa-bility in rriddle-scale networks.展开更多
Failure detection module is one of important components in fault-tolerant distributed systems,especially cloud platform.However,to achieve fast and accurate detection of failure becomes more and more difficult especia...Failure detection module is one of important components in fault-tolerant distributed systems,especially cloud platform.However,to achieve fast and accurate detection of failure becomes more and more difficult especially when network and other resources' status keep changing.This study presented an efficient adaptive failure detection mechanism based on volterra series,which can use a small amount of data for predicting.The mechanism uses a volterra filter for time series prediction and a decision tree for decision making.Major contributions are applying volterra filter in cloud failure prediction,and introducing a user factor for different QoS requirements in different modules and levels of IaaS.Detailed implementation is proposed,and an evaluation is performed in Beijing and Guangzhou experiment environment.展开更多
Failure depth of coal seam floors is one of the important considerations that must be kept in mind when mining is carried out above a confined aquifer. In order to study the factors that affect the failure depth of co...Failure depth of coal seam floors is one of the important considerations that must be kept in mind when mining is carried out above a confined aquifer. In order to study the factors that affect the failure depth of coal seam floors such as mining depth, coal seam pitch, mining thickness, workface length and faults, we propose a combined artificial neural networks (ANN) prediction model for failure depth of coal seam floors on the basis of existing engineering data by using genetic algorithms to train the ANN. A practical engineering application at the Taoyuan Coal Mine indicates that this method can effectively determine the network struc- ture and training parameters, with the predicted results agreeing with practical measurements. Therefore, this method can be applied to relevant engineering projects with satisfactory results.展开更多
This study sought to investigate whether low dose dobutamine MRI can detect residual myocardial viability in patients with chronic myocardial infarction and left ventricular dysfunction. Methods. Eleven patients with ...This study sought to investigate whether low dose dobutamine MRI can detect residual myocardial viability in patients with chronic myocardial infarction and left ventricular dysfunction. Methods. Eleven patients with chronic myocardial infarction and left ventricular dysfunction were employed for identification of viable myocardium by cine MRI during dobutamine infusion. All patients underwent coronary angiography and left ventriculography, 18 FDG PET, MRI at rest and stress.The systolic wall thickening measured at rest and during stress was compared with the results of 18 FDG PET, respectively. Results. A significant difference of either dobutamine induced systolic wall thickening (SWth stress ) or dobutamine induced contractile reserve (ΔSWth= SWth stress - SWth rest ) was present between viable and scar regions (1 0±0 3 versus -0 3 ±0 1, P<0 01; 1 0±0 3 versus -0 2±0 2, P<0 01). Conclusions. Dobutamine induced contractile reserve can be predicted in the regions of akinesia or dyskinesia at rest when systolic wall thickening was 1 0 mm during dobutamine stimulation.展开更多
To reduce excessive computing and communication loads of traditional fault detection methods,a neighbor-data analysis based node fault detection method is proposed.First,historical data is analyzed to confirm the conf...To reduce excessive computing and communication loads of traditional fault detection methods,a neighbor-data analysis based node fault detection method is proposed.First,historical data is analyzed to confirm the confidence level of sensor nodes.Then a node's reading data is compared with neighbor nodes' which are of good confidence level.Decision can be made whether this node is a failure or not.Simulation shows this method has good effect on fault detection accuracy and transient fault tolerance,and never transfers communication and computing overloading to sensor nodes.展开更多
A marine propulsion system is a very complicated system composed of many mechanical components.As a result,the vibration signal of a gearbox in the system is strongly coupled with the vibration signatures of other com...A marine propulsion system is a very complicated system composed of many mechanical components.As a result,the vibration signal of a gearbox in the system is strongly coupled with the vibration signatures of other components including a diesel engine and main shaft.It is therefore imperative to assess the coupling effect on diagnostic reliability in the process of gear fault diagnosis.For this reason,a fault detection and diagnosis method based on bispectrum analysis and artificial neural networks (ANNs) was proposed for the gearbox with consideration given to the impact of the other components in marine propulsion systems.To monitor the gear conditions,the bispectrum analysis was first employed to detect gear faults.The amplitude-frequency plots containing gear characteristic signals were then attained based on the bispectrum technique,which could be regarded as an index actualizing forepart gear faults diagnosis.Both the back propagation neural network (BPNN) and the radial-basis function neural network (RBFNN) were applied to identify the states of the gearbox.The numeric and experimental test results show the bispectral patterns of varying gear fault severities are different so that distinct fault features of the vibrant signal of a marine gearbox can be extracted effectively using the bispectrum,and the ANN classification method has achieved high detection accuracy.Hence,the proposed diagnostic techniques have the capability of diagnosing marine gear faults in the earlier phases,and thus have application importance.展开更多
The IEEE Standard 1149.1 boundary scan (BS) implementation provides the internal access required for testing the digital printed circuit board (PCB). However, the integrity of the boundary scan test infrastructure sh...The IEEE Standard 1149.1 boundary scan (BS) implementation provides the internal access required for testing the digital printed circuit board (PCB). However, the integrity of the boundary scan test infrastructure should be tested first to guarantee the validation of the results of the rest functional test and diagnosis. This paper describes the fault models and test principles of the BS test access port (TAP) lines on PCBs. A test algorithm with high fault coverage and short time is then presented for the PCB on which all ICs are BS ones.展开更多
Fault recognition and coal seam thickness forecast are important problems in mineral resource prediction. Knowledge of multiple disciplines, which include mining engineering, mine geology, seismic prospecting etc, was...Fault recognition and coal seam thickness forecast are important problems in mineral resource prediction. Knowledge of multiple disciplines, which include mining engineering, mine geology, seismic prospecting etc, was used synthetically. Artificial neural network was combined with genetic algorithm to found integrated AI method of genetic algorithm artificial neural network(GA ANN). Fault recognition and coal seam thickness forecast were carried to completion by case studies. And the research results are satisfactory.展开更多
In recent times, the prevalence of pulmonary arterial hypertension creased prevalence of hypertension, diabetes, obesity, arterial stiffness, （PAH） is more commonly seen among elderly populations. The inas well as d...In recent times, the prevalence of pulmonary arterial hypertension creased prevalence of hypertension, diabetes, obesity, arterial stiffness, （PAH） is more commonly seen among elderly populations. The inas well as diastolic dysfunction, may cause endothelial dysfunction and affect pulmonary vasculature. Furthermore, older patients have certain differences in clinical characteristics and outcomes. In this article the special characteristics of aging in PAH patients have been reviewed, while the risk predictors of elderly patients are also discussed.展开更多
基金Supported by the National High Technology Research and Development Program of China (‘863’Program) (2006AA12Z313)~~
文摘A new integrity metric for navigation systems is proposed based on the measurement domain. Proba-hilistic optimization design offers tools for fault detection by considering the required navigation performance （RNP） parameter and the uncertainty noise. The choice of the proper performance parameter provided the single-valued mapping with the missed detection probability estimates the probability of failure. The desirable characteristics of the residual sensitivity matrix are exploited to increase the efficiency for identifying erroneous observations. The algorithm can be used to support the performance specification and the efficient calculation of the integrity monitoring process. The simulation for non-precision approach （NPA） validates both the viability and the effectiveness of the proposed algorithm.
文摘This paper presents a new information fusion filter in integrated navigation. The method can improve the fault-tolerant performance and make well fault detection, isolation and reconfiguration of the integrated navigation system exist. Based on three sensors'(strapdown system, GPS receiver, Doppler radar) information fusion, a fault-tolerant navigation system is designed with this information fusion filter and two-ellipsoid overlap test. Simulation results show that the design is efficient with the soft-failure of gyro, accelerator, GPS receiver and Doppler radar.
文摘Aim To detect sensor failure in control system using a single sensor signal. Methods A neural predictor was designed based on a radial basis function network(RBFN), and the neural predictor learned the sensor signal on line with a hybrid algorithm composed of n means clustering and Kalman filter and then gave the estimation of the sensor signal at the next step. If the difference between the estimation and the actural values of the sensor signal exceeded a threshold, the sensor could be declared to have a failure. The choice of the failure detection threshold depends on the noise variance and the possible prediction error of neural predictor. Results and Conclusion\ The computer simulation results show the proposed method can detect sensor failure correctly for a gyro in an automotive engine.
文摘Modern automobile testing systems are complexly computerized measure and control systems, and used in automobile vehicle design centers and assembly plants. Their performance is critical but difficult to be monitored efficiently and in real time. This paper introduces an Internet based remote monitoring system for automobile testing systems, and the design and the implementation using Web database and Socket techniques.
基金supported by the National Basic Research Program under Grant No. G1999032707the National High Technology Research and Development Program of China under Grant No. 2008AA01A303the Supporting Program of the"Eleventh Five-year Plan"for Sci & Tech Research of China under Grant No. 2008BAH37B03
文摘A new passive method for automatic dis-covery and bcation of network failure is proposed. This method employs a passive measurement to collect infonmtion and events from network traffic, and em-ploys a rrodel-based reasoning system to detect and locate network faults. Measurement points are de-ployed in a backbone network to capture the traffic and then evaluate the Quality of Service （QoS） metrics of end-to-end IP conversations. A muting rrodel is al-so established for the observed network to simulate the attributes and activities of reuters and links. This muting model also deduces the muting path for each IP conversation, and thus the QoS metrics of IP con-versations are mapped into the metrics of paths. With the inforrmtion of shared links of overlapping paths and network torrography technique, the QoS metrics of links can also be estimated, and the poorly rated links are picked out as failure points. This method is imple-mented in a tool named FaultMan, which is deployed in a campus network. Test results have shown its availa-bility in rriddle-scale networks.
基金supported by the National High-tech Research and Development Program(863) of China under Grant No. 2011AA01A102
文摘Failure detection module is one of important components in fault-tolerant distributed systems,especially cloud platform.However,to achieve fast and accurate detection of failure becomes more and more difficult especially when network and other resources' status keep changing.This study presented an efficient adaptive failure detection mechanism based on volterra series,which can use a small amount of data for predicting.The mechanism uses a volterra filter for time series prediction and a decision tree for decision making.Major contributions are applying volterra filter in cloud failure prediction,and introducing a user factor for different QoS requirements in different modules and levels of IaaS.Detailed implementation is proposed,and an evaluation is performed in Beijing and Guangzhou experiment environment.
基金Projects 50874103 supported by the National Natural Science Foundation of China2006CB202210 by the National Basic Research Program of China+1 种基金BK2008135 by the Natural Science Foundation of Jiangsu Provincethe Qing-lan Project of Jiangsu Province
文摘Failure depth of coal seam floors is one of the important considerations that must be kept in mind when mining is carried out above a confined aquifer. In order to study the factors that affect the failure depth of coal seam floors such as mining depth, coal seam pitch, mining thickness, workface length and faults, we propose a combined artificial neural networks (ANN) prediction model for failure depth of coal seam floors on the basis of existing engineering data by using genetic algorithms to train the ANN. A practical engineering application at the Taoyuan Coal Mine indicates that this method can effectively determine the network struc- ture and training parameters, with the predicted results agreeing with practical measurements. Therefore, this method can be applied to relevant engineering projects with satisfactory results.
文摘This study sought to investigate whether low dose dobutamine MRI can detect residual myocardial viability in patients with chronic myocardial infarction and left ventricular dysfunction. Methods. Eleven patients with chronic myocardial infarction and left ventricular dysfunction were employed for identification of viable myocardium by cine MRI during dobutamine infusion. All patients underwent coronary angiography and left ventriculography, 18 FDG PET, MRI at rest and stress.The systolic wall thickening measured at rest and during stress was compared with the results of 18 FDG PET, respectively. Results. A significant difference of either dobutamine induced systolic wall thickening (SWth stress ) or dobutamine induced contractile reserve (ΔSWth= SWth stress - SWth rest ) was present between viable and scar regions (1 0±0 3 versus -0 3 ±0 1, P<0 01; 1 0±0 3 versus -0 2±0 2, P<0 01). Conclusions. Dobutamine induced contractile reserve can be predicted in the regions of akinesia or dyskinesia at rest when systolic wall thickening was 1 0 mm during dobutamine stimulation.
基金supported by the National Basic Research Program of China(2007CB310703)the High Technical Research and Development Program of China(2008AA01Z201)+1 种基金the National Natural Science Foundlation of China(60821001,60802035,60973108)Chinese Universities Science Fund(BUPT2009RC0504)
文摘To reduce excessive computing and communication loads of traditional fault detection methods,a neighbor-data analysis based node fault detection method is proposed.First,historical data is analyzed to confirm the confidence level of sensor nodes.Then a node's reading data is compared with neighbor nodes' which are of good confidence level.Decision can be made whether this node is a failure or not.Simulation shows this method has good effect on fault detection accuracy and transient fault tolerance,and never transfers communication and computing overloading to sensor nodes.
基金Supported by the National Natural Sciences Foundation of China (No. 50975213 and No. 50705070)Doctoral Fund for the New Teachers of Ministry of Education of China (No. 20070497029)the Program of Introducing Talents of Discipline to Universities (No. B08031)
文摘A marine propulsion system is a very complicated system composed of many mechanical components.As a result,the vibration signal of a gearbox in the system is strongly coupled with the vibration signatures of other components including a diesel engine and main shaft.It is therefore imperative to assess the coupling effect on diagnostic reliability in the process of gear fault diagnosis.For this reason,a fault detection and diagnosis method based on bispectrum analysis and artificial neural networks (ANNs) was proposed for the gearbox with consideration given to the impact of the other components in marine propulsion systems.To monitor the gear conditions,the bispectrum analysis was first employed to detect gear faults.The amplitude-frequency plots containing gear characteristic signals were then attained based on the bispectrum technique,which could be regarded as an index actualizing forepart gear faults diagnosis.Both the back propagation neural network (BPNN) and the radial-basis function neural network (RBFNN) were applied to identify the states of the gearbox.The numeric and experimental test results show the bispectral patterns of varying gear fault severities are different so that distinct fault features of the vibrant signal of a marine gearbox can be extracted effectively using the bispectrum,and the ANN classification method has achieved high detection accuracy.Hence,the proposed diagnostic techniques have the capability of diagnosing marine gear faults in the earlier phases,and thus have application importance.
文摘The IEEE Standard 1149.1 boundary scan (BS) implementation provides the internal access required for testing the digital printed circuit board (PCB). However, the integrity of the boundary scan test infrastructure should be tested first to guarantee the validation of the results of the rest functional test and diagnosis. This paper describes the fault models and test principles of the BS test access port (TAP) lines on PCBs. A test algorithm with high fault coverage and short time is then presented for the PCB on which all ICs are BS ones.
基金National Natural Science Foundation of China(5 97740 0 5 )
文摘Fault recognition and coal seam thickness forecast are important problems in mineral resource prediction. Knowledge of multiple disciplines, which include mining engineering, mine geology, seismic prospecting etc, was used synthetically. Artificial neural network was combined with genetic algorithm to found integrated AI method of genetic algorithm artificial neural network(GA ANN). Fault recognition and coal seam thickness forecast were carried to completion by case studies. And the research results are satisfactory.
文摘In recent times, the prevalence of pulmonary arterial hypertension creased prevalence of hypertension, diabetes, obesity, arterial stiffness, （PAH） is more commonly seen among elderly populations. The inas well as diastolic dysfunction, may cause endothelial dysfunction and affect pulmonary vasculature. Furthermore, older patients have certain differences in clinical characteristics and outcomes. In this article the special characteristics of aging in PAH patients have been reviewed, while the risk predictors of elderly patients are also discussed.
