During normal de-ballasting operations for floating docks,each ballast pump independently manages a specific group of ballast tanks.However,when a pump malfunctions,a connection valve between the two groups of ballast...During normal de-ballasting operations for floating docks,each ballast pump independently manages a specific group of ballast tanks.However,when a pump malfunctions,a connection valve between the two groups of ballast water systems is opened.This allows the adjacent pump to serve as a helper pump,simultaneously controlling two groups of ballast water systems.This study explores a full-scale floating dock’s dynamic behaviours during the de-ballasting operations under this situation through a numerical model.In the developed numerical model,the dock is described as a six-degree-of-freedom rigid body which is subjected to hydrostatic,hydrodynamic,and mooring loads.A hydraulic model of the piping network of the malfunctioning pump and the helper pump is proposed.A modified P-controller regulates opening angles of all tank valves for minimal pitch and roll.Two configurations of the floating dock,i.e.,a single floating dock and a floating dock with an onboard vessel,are considered.The numerical results show that the optimal helper pumps can be identified regarding the pumps’total de-ballasting capacity and the dock’s stability.The most severe scenarios can be determined in term of the dock’s maximum draught differences caused by its roll and pitch.The observed maximum draught differences remain small relative to the dock’s width,indicating the effectiveness of employing helper pumps and the proposed automatic ballast control strategy for one-pump malfunction scenarios.展开更多
In recent years,intelligent data-driven prognostic methods have been successfully developed,and good machinery health assessment performance has been achieved through explorations of data from multiple sensors.However...In recent years,intelligent data-driven prognostic methods have been successfully developed,and good machinery health assessment performance has been achieved through explorations of data from multiple sensors.However,existing datafusion prognostic approaches generally rely on the data availability of all sensors,and are vulnerable to potential sensor malfunctions,which are likely to occur in real industries especially for machines in harsh operating environments.In this paper,a deep learning-based remaining useful life(RUL)prediction method is proposed to address the sensor malfunction problem.A global feature extraction scheme is adopted to fully exploit information of different sensors.Adversarial learning is further introduced to extract generalized sensor-invariant features.Through explorations of both global and shared features,promising and robust RUL prediction performance can be achieved by the proposed method in the testing scenarios with sensor malfunctions.The experimental results suggest the proposed approach is well suited for real industrial applications.展开更多
Vanishing white matter （VWM） disease - a disease of the cytosolic translation machinery： VWM is a recessive genet- ic neurodegenerative disease caused by mutations in any of the five genes encoding the subunits of ...Vanishing white matter （VWM） disease - a disease of the cytosolic translation machinery： VWM is a recessive genet- ic neurodegenerative disease caused by mutations in any of the five genes encoding the subunits of translation initiation factor 2B （eIF2B） （Leegwater et al., 2001; OMIM 306896）.展开更多
Enhancing the security of Wireless Sensor Networks(WSNs)improves the usability of their applications.Therefore,finding solutions to various attacks,such as the blackhole attack,is crucial for the success of WSN applic...Enhancing the security of Wireless Sensor Networks(WSNs)improves the usability of their applications.Therefore,finding solutions to various attacks,such as the blackhole attack,is crucial for the success of WSN applications.This paper proposes an enhanced version of the AODV(Ad Hoc On-Demand Distance Vector)protocol capable of detecting blackholes and malfunctioning benign nodes in WSNs,thereby avoiding them when delivering packets.The proposed version employs a network-based reputation system to select the best and most secure path to a destination.To achieve this goal,the proposed version utilizes the Watchdogs/Pathrater mechanisms in AODV to gather and broadcast reputations to all network nodes to build the network-based reputation system.To minimize the network overhead of the proposed approach,the paper uses reputation aggregator nodes only for forwarding reputation tables.Moreover,to reduce the overhead of updating reputation tables,the paper proposes three mechanisms,which are the prompt broadcast,the regular broadcast,and the light broadcast approaches.The proposed enhanced version has been designed to perform effectively in dynamic environments such as mobile WSNs where nodes,including blackholes,move continuously,which is considered a challenge for other protocols.Using the proposed enhanced protocol,a node evaluates the security of different routes to a destination and can select the most secure routing path.The paper provides an algorithm that explains the proposed protocol in detail and demonstrates a case study that shows the operations of calculating and updating reputation values when nodes move across different zones.Furthermore,the paper discusses the proposed approach’s overhead analysis to prove the proposed enhancement’s correctness and applicability.展开更多
After long-term operation,the performance of components in the GTCC system deteriorates and requires timely maintenance.Due to the inability to directly measure the degree of component malfunction,it is necessary to u...After long-term operation,the performance of components in the GTCC system deteriorates and requires timely maintenance.Due to the inability to directly measure the degree of component malfunction,it is necessary to use advanced exergy analysis diagnosis methods to characterize the components’health condition(degree of malfunction)through operation data of the GTCC system.The dissipative temperature is used to describe the degree of malfunction of different components in the GTCC system,and an advanced exergy analysis diagnostic method is used to establish a database of overall operating condition component malfunctions in theGTCC system.Ebsilon software is used to simulate the critical parameters of the malfunctions of the GTCC system components and to obtain the changes in the dissipative temperature of different components.Meanwhile,the fuel consumption and economic changes of the GTCC system on a characteristic power supply day under health and malfunction conditions are analyzed.Finally,the effects of maintenance costs,electricity,and gas prices on maintenance expenses and profits are analyzed.The results show that the GTCC system maintenance profit is 6.07$/MWh,while the GTCC system maintenance expense is 5.83$/MWh.Compared with the planned maintenancemode,the malfunction maintenance mode saves 0.24$/MWh.Simultaneously,the maintenance coefficient of GTCC should be adjusted under different malfunctions to obtain a more accurate maintenance period.展开更多
Failure of an automated blood pressure cuff to deflate when a patient is under general anesthesia can lead to catastrophic consequences if unnoticed for more than three hours [1]. We present this as a hearsay case in ...Failure of an automated blood pressure cuff to deflate when a patient is under general anesthesia can lead to catastrophic consequences if unnoticed for more than three hours [1]. We present this as a hearsay case in which an automated blood pressure cuff of the Spacelabs Ultraview Clinical Workstation monitor (model No. 90385) applied pressure for about five hours resulting in limb thrombosis. In order to analyze this catastrophe, simulation scenarios were tested to elucidate the possible errors and malfunctions that may have led to this injury. We present the analysis of the advantages and validity of the hearsay case report. We also include our proposed criteria that should be required when a hearsay case is considered for publication.展开更多
At present, malfunction of implantable cardioverter-defibrillator （ICD） lead has already gradually become a serious clinic problems for doctors,to well identify and manage the frequent inappropriate therapy induced ...At present, malfunction of implantable cardioverter-defibrillator （ICD） lead has already gradually become a serious clinic problems for doctors,to well identify and manage the frequent inappropriate therapy induced by sensing abnormality due to pacing/sensing （P/S） lead malfunctions of ICD are another kind of challenge for cardiologists. Methods Lead malfunctions of ICD were identified during follow-up period, in which insulation layer rupture and lead fracture were the most frequent. Except for conventional examinations, events histories and pacing parameters were reviewed from electrogram of ICD to determine the causes of lead malfunctions and guide the management. Results Frequent inappropriate therapy induced by sensing abnormality due to P/S lead malfunctions （normal high-voltage part of ICD lead） was identified in five patients and successfully managed by simply implanting an additional P/S lead but keeping the original defibrillation lead （high-voltage part of the ICD lead）. Follow-up results showed that this method was safe and effective enough for these patients. Conclusions Inappropriate therapy induced by P/S lead malfunction could be well managed by only replacing P/S lead but keeping the normal original defibrillation lead, which could also greatly decrease the risk and medical cost than extracting original lead of ICD or adding a new defibrillation lead.展开更多
In order to investigate the dynamic behavior, to study a variety of operational problems, to apply different control techniques and to suggest functional improvements of a high power electromechanical system, a pilot ...In order to investigate the dynamic behavior, to study a variety of operational problems, to apply different control techniques and to suggest functional improvements of a high power electromechanical system, a pilot study on a low power laboratory simulating system is proposed in this paper. Particularly, to investigate operational problems of a twin AC drive with asynchronous machines used for cement kilns, an under-scale laboratory simulating system has been developed and experimental results are being presented in this research work.展开更多
对轮式移动机器人(Wheeled Mobile Robot,WMR)发生执行器故障和输入饱和时容错控制问题进行研究,设计了一种自适应容错控制器(Adaptive FaultTolerant Controller,AFTC),可在故障信息未知的情况下解决上述问题。首先,设计了线性扩张观测...对轮式移动机器人(Wheeled Mobile Robot,WMR)发生执行器故障和输入饱和时容错控制问题进行研究,设计了一种自适应容错控制器(Adaptive FaultTolerant Controller,AFTC),可在故障信息未知的情况下解决上述问题。首先,设计了线性扩张观测器(Linear Extended State Observer,LESO)对偏置故障和干扰进行在线估计;然后,基于积分滑模设计了一种自适应控制律来补偿部分失效控制,并结合指数和变速趋近律来削弱滑模抖振;最后,设计了一种饱和辅助系统,利用其辅助变量对自适应控制律在线调整,使控制量在限幅范围内。利用李雅普诺夫稳定性理论,证明了在执行器故障和输入饱和的情况下,WMR的前进速度和方位角可以渐近地跟踪参考轨迹,并通过对比数值仿真验证了所设计的容错控制策略的有效性。展开更多
基金The article is a result of joined research performed during the project:“A Floating Dock Digital Twin towards Efficient,Safer and Autonomous Docking Operations”-NOR/POLNOR/DigiFloDock/0009/2019-00 which is cofinanced by the programme“Applied research”under the Norwegian Financial Mechanisms 2014-2021 POLNOR 2019-Digital and Industry.
文摘During normal de-ballasting operations for floating docks,each ballast pump independently manages a specific group of ballast tanks.However,when a pump malfunctions,a connection valve between the two groups of ballast water systems is opened.This allows the adjacent pump to serve as a helper pump,simultaneously controlling two groups of ballast water systems.This study explores a full-scale floating dock’s dynamic behaviours during the de-ballasting operations under this situation through a numerical model.In the developed numerical model,the dock is described as a six-degree-of-freedom rigid body which is subjected to hydrostatic,hydrodynamic,and mooring loads.A hydraulic model of the piping network of the malfunctioning pump and the helper pump is proposed.A modified P-controller regulates opening angles of all tank valves for minimal pitch and roll.Two configurations of the floating dock,i.e.,a single floating dock and a floating dock with an onboard vessel,are considered.The numerical results show that the optimal helper pumps can be identified regarding the pumps’total de-ballasting capacity and the dock’s stability.The most severe scenarios can be determined in term of the dock’s maximum draught differences caused by its roll and pitch.The observed maximum draught differences remain small relative to the dock’s width,indicating the effectiveness of employing helper pumps and the proposed automatic ballast control strategy for one-pump malfunction scenarios.
基金supported by the National Science Fund for Distinguished Young Scholars of China(52025056)Fundamental Research Funds for the Central Universities(xzy012022062)。
文摘In recent years,intelligent data-driven prognostic methods have been successfully developed,and good machinery health assessment performance has been achieved through explorations of data from multiple sensors.However,existing datafusion prognostic approaches generally rely on the data availability of all sensors,and are vulnerable to potential sensor malfunctions,which are likely to occur in real industries especially for machines in harsh operating environments.In this paper,a deep learning-based remaining useful life(RUL)prediction method is proposed to address the sensor malfunction problem.A global feature extraction scheme is adopted to fully exploit information of different sensors.Adversarial learning is further introduced to extract generalized sensor-invariant features.Through explorations of both global and shared features,promising and robust RUL prediction performance can be achieved by the proposed method in the testing scenarios with sensor malfunctions.The experimental results suggest the proposed approach is well suited for real industrial applications.
基金funded by The Legacy Heritage Bio-Medical Program of the Israel Science Foundation(grant No.1629/13)
文摘Vanishing white matter （VWM） disease - a disease of the cytosolic translation machinery： VWM is a recessive genet- ic neurodegenerative disease caused by mutations in any of the five genes encoding the subunits of translation initiation factor 2B （eIF2B） （Leegwater et al., 2001; OMIM 306896）.
文摘Enhancing the security of Wireless Sensor Networks(WSNs)improves the usability of their applications.Therefore,finding solutions to various attacks,such as the blackhole attack,is crucial for the success of WSN applications.This paper proposes an enhanced version of the AODV(Ad Hoc On-Demand Distance Vector)protocol capable of detecting blackholes and malfunctioning benign nodes in WSNs,thereby avoiding them when delivering packets.The proposed version employs a network-based reputation system to select the best and most secure path to a destination.To achieve this goal,the proposed version utilizes the Watchdogs/Pathrater mechanisms in AODV to gather and broadcast reputations to all network nodes to build the network-based reputation system.To minimize the network overhead of the proposed approach,the paper uses reputation aggregator nodes only for forwarding reputation tables.Moreover,to reduce the overhead of updating reputation tables,the paper proposes three mechanisms,which are the prompt broadcast,the regular broadcast,and the light broadcast approaches.The proposed enhanced version has been designed to perform effectively in dynamic environments such as mobile WSNs where nodes,including blackholes,move continuously,which is considered a challenge for other protocols.Using the proposed enhanced protocol,a node evaluates the security of different routes to a destination and can select the most secure routing path.The paper provides an algorithm that explains the proposed protocol in detail and demonstrates a case study that shows the operations of calculating and updating reputation values when nodes move across different zones.Furthermore,the paper discusses the proposed approach’s overhead analysis to prove the proposed enhancement’s correctness and applicability.
基金supported by the China Postdoctoral Science Foundation(Grant number:370140).
文摘After long-term operation,the performance of components in the GTCC system deteriorates and requires timely maintenance.Due to the inability to directly measure the degree of component malfunction,it is necessary to use advanced exergy analysis diagnosis methods to characterize the components’health condition(degree of malfunction)through operation data of the GTCC system.The dissipative temperature is used to describe the degree of malfunction of different components in the GTCC system,and an advanced exergy analysis diagnostic method is used to establish a database of overall operating condition component malfunctions in theGTCC system.Ebsilon software is used to simulate the critical parameters of the malfunctions of the GTCC system components and to obtain the changes in the dissipative temperature of different components.Meanwhile,the fuel consumption and economic changes of the GTCC system on a characteristic power supply day under health and malfunction conditions are analyzed.Finally,the effects of maintenance costs,electricity,and gas prices on maintenance expenses and profits are analyzed.The results show that the GTCC system maintenance profit is 6.07$/MWh,while the GTCC system maintenance expense is 5.83$/MWh.Compared with the planned maintenancemode,the malfunction maintenance mode saves 0.24$/MWh.Simultaneously,the maintenance coefficient of GTCC should be adjusted under different malfunctions to obtain a more accurate maintenance period.
文摘Failure of an automated blood pressure cuff to deflate when a patient is under general anesthesia can lead to catastrophic consequences if unnoticed for more than three hours [1]. We present this as a hearsay case in which an automated blood pressure cuff of the Spacelabs Ultraview Clinical Workstation monitor (model No. 90385) applied pressure for about five hours resulting in limb thrombosis. In order to analyze this catastrophe, simulation scenarios were tested to elucidate the possible errors and malfunctions that may have led to this injury. We present the analysis of the advantages and validity of the hearsay case report. We also include our proposed criteria that should be required when a hearsay case is considered for publication.
文摘At present, malfunction of implantable cardioverter-defibrillator （ICD） lead has already gradually become a serious clinic problems for doctors,to well identify and manage the frequent inappropriate therapy induced by sensing abnormality due to pacing/sensing （P/S） lead malfunctions of ICD are another kind of challenge for cardiologists. Methods Lead malfunctions of ICD were identified during follow-up period, in which insulation layer rupture and lead fracture were the most frequent. Except for conventional examinations, events histories and pacing parameters were reviewed from electrogram of ICD to determine the causes of lead malfunctions and guide the management. Results Frequent inappropriate therapy induced by sensing abnormality due to P/S lead malfunctions （normal high-voltage part of ICD lead） was identified in five patients and successfully managed by simply implanting an additional P/S lead but keeping the original defibrillation lead （high-voltage part of the ICD lead）. Follow-up results showed that this method was safe and effective enough for these patients. Conclusions Inappropriate therapy induced by P/S lead malfunction could be well managed by only replacing P/S lead but keeping the normal original defibrillation lead, which could also greatly decrease the risk and medical cost than extracting original lead of ICD or adding a new defibrillation lead.
文摘In order to investigate the dynamic behavior, to study a variety of operational problems, to apply different control techniques and to suggest functional improvements of a high power electromechanical system, a pilot study on a low power laboratory simulating system is proposed in this paper. Particularly, to investigate operational problems of a twin AC drive with asynchronous machines used for cement kilns, an under-scale laboratory simulating system has been developed and experimental results are being presented in this research work.
文摘对轮式移动机器人(Wheeled Mobile Robot,WMR)发生执行器故障和输入饱和时容错控制问题进行研究,设计了一种自适应容错控制器(Adaptive FaultTolerant Controller,AFTC),可在故障信息未知的情况下解决上述问题。首先,设计了线性扩张观测器(Linear Extended State Observer,LESO)对偏置故障和干扰进行在线估计;然后,基于积分滑模设计了一种自适应控制律来补偿部分失效控制,并结合指数和变速趋近律来削弱滑模抖振;最后,设计了一种饱和辅助系统,利用其辅助变量对自适应控制律在线调整,使控制量在限幅范围内。利用李雅普诺夫稳定性理论,证明了在执行器故障和输入饱和的情况下,WMR的前进速度和方位角可以渐近地跟踪参考轨迹,并通过对比数值仿真验证了所设计的容错控制策略的有效性。
