The contact network dropper works in a harsh environment,and suffers from the impact effect of pantographs during running of trains,which may lead to faults such as slack and broken of the dropper wire and broken of t...The contact network dropper works in a harsh environment,and suffers from the impact effect of pantographs during running of trains,which may lead to faults such as slack and broken of the dropper wire and broken of the current-carrying ring.Due to the low intelligence and poor accuracy of the dropper fault detection network,an improved fully convolutional one-stage(FCOS)object detection network was proposed to improve the detection capability of the dropper condition.Firstly,by adjusting the parameterαin the network focus loss function,the problem of positive and negative sample imbalance in the network training process was eliminated.Secondly,the generalized intersection over union(GIoU)calculation was introduced to enhance the network’s ability to recognize the relative spatial positions of the prediction box and the bounding box during the regression calculation.Finally,the improved network was used to detect the status of dropper pictures.The detection speed was 150 sheets per millisecond,and the MAP of different status detection was 0.9512.Through the simulation comparison with other object detection networks,it was proved that the improved FCOS network had advantages in both detection time and accuracy,and could identify the state of dropper accurately.展开更多
In the Large Helical Device(LHD),diborane(B2H6)is used as a standard boron source for boronization,which is assisted by helium glow discharges.In 2019,a new Impurity Powder Dropper(IPD)system was installed and is unde...In the Large Helical Device(LHD),diborane(B2H6)is used as a standard boron source for boronization,which is assisted by helium glow discharges.In 2019,a new Impurity Powder Dropper(IPD)system was installed and is under evaluation as a real-time wall conditioning technique.In the LHD,which is a large-sized heliotron device,an additional helium(He)glow discharge cleaning(GDC)after boronization was operated for a reduction in hydrogen recycling from the coated boron layers.This operational time of 3 h was determined by spectroscopic data during glow discharges.A flat hydrogen profile is obtained on the top surface of the coated boron on the specimen exposed to boronization.The results suggest a reduction in hydrogen at the top surface by He-GDC.Trapped oxygen in coated boron was obtained by boronization,and the coated boron,which has boron-oxide,on the first wall by B-IPD was also shown.Considering the difference in coating areas between B2H6 boronization and B-IPD operation,it would be most effective to use the IPD and B2H6 boronization coating together for optimized wall conditioning.展开更多
Packet dropping in a mobile ad hoc network can manifest itself as the data plane attacks as well as control plane attacks.The former deal with malicious nodes performing packet drop on the data packets following the r...Packet dropping in a mobile ad hoc network can manifest itself as the data plane attacks as well as control plane attacks.The former deal with malicious nodes performing packet drop on the data packets following the route formation and the latter deal with those malicious nodes which either drop or manipulate the control packets to degrade the network performance.The idea of the proposed approach is that during the route establishment,each of the on-path nodes is provided with pre-computed hash values which have to be used to provide a unique acknowledgement value to the upstream neighbor which acts as a proof of the forwarding activity.The analysis phase results in the detection of nodes which exhibited malicious behavior in the current communication session so as to avoid them in the future communication sessions resulting in an improved packet delivery fraction even in the presence of one or more malicious nodes in the network.The communication overhead incurred is minimum since the acknowledgement reports are sent to the destination for a transmission of N packets rather than an individual acknowledgement for each transmitted packet.In contrast to some of the existing techniques,the proposed mechanism is not dependent on the deployment of additional infrastructure like special Intrusion Detection System(IDS)nodes.The only overhead incurred is in the form of control packets exchanged for the reports request and the reports submission.展开更多
基金supported by Natural Science Foundation of Gansu Province(No.20JR10RA216)。
文摘The contact network dropper works in a harsh environment,and suffers from the impact effect of pantographs during running of trains,which may lead to faults such as slack and broken of the dropper wire and broken of the current-carrying ring.Due to the low intelligence and poor accuracy of the dropper fault detection network,an improved fully convolutional one-stage(FCOS)object detection network was proposed to improve the detection capability of the dropper condition.Firstly,by adjusting the parameterαin the network focus loss function,the problem of positive and negative sample imbalance in the network training process was eliminated.Secondly,the generalized intersection over union(GIoU)calculation was introduced to enhance the network’s ability to recognize the relative spatial positions of the prediction box and the bounding box during the regression calculation.Finally,the improved network was used to detect the status of dropper pictures.The detection speed was 150 sheets per millisecond,and the MAP of different status detection was 0.9512.Through the simulation comparison with other object detection networks,it was proved that the improved FCOS network had advantages in both detection time and accuracy,and could identify the state of dropper accurately.
基金supported by NIFS budgets,KOBF031,ULFF004,KUHR032partly supported by JSPS KAKENHI 18K04999+2 种基金JSPS-CAS Bilateral Joint Research Projects,“Control of wall recycling on metallic plasma-facing materials in fusion reactor”2019-2022,(No.GJHZ201984)the Chinese Academy of Sciences President’s International Fellowship Initiative Grant No.2024VMB0003 in FY2023the U.S.Department Of Energy under Contract No.DE-AC02-09CH11466 with Princeton University。
文摘In the Large Helical Device(LHD),diborane(B2H6)is used as a standard boron source for boronization,which is assisted by helium glow discharges.In 2019,a new Impurity Powder Dropper(IPD)system was installed and is under evaluation as a real-time wall conditioning technique.In the LHD,which is a large-sized heliotron device,an additional helium(He)glow discharge cleaning(GDC)after boronization was operated for a reduction in hydrogen recycling from the coated boron layers.This operational time of 3 h was determined by spectroscopic data during glow discharges.A flat hydrogen profile is obtained on the top surface of the coated boron on the specimen exposed to boronization.The results suggest a reduction in hydrogen at the top surface by He-GDC.Trapped oxygen in coated boron was obtained by boronization,and the coated boron,which has boron-oxide,on the first wall by B-IPD was also shown.Considering the difference in coating areas between B2H6 boronization and B-IPD operation,it would be most effective to use the IPD and B2H6 boronization coating together for optimized wall conditioning.
基金The author would like to thank Deanship of Scientific Research at Majmaah University for supporting this work under Project Number 1439-59.
文摘Packet dropping in a mobile ad hoc network can manifest itself as the data plane attacks as well as control plane attacks.The former deal with malicious nodes performing packet drop on the data packets following the route formation and the latter deal with those malicious nodes which either drop or manipulate the control packets to degrade the network performance.The idea of the proposed approach is that during the route establishment,each of the on-path nodes is provided with pre-computed hash values which have to be used to provide a unique acknowledgement value to the upstream neighbor which acts as a proof of the forwarding activity.The analysis phase results in the detection of nodes which exhibited malicious behavior in the current communication session so as to avoid them in the future communication sessions resulting in an improved packet delivery fraction even in the presence of one or more malicious nodes in the network.The communication overhead incurred is minimum since the acknowledgement reports are sent to the destination for a transmission of N packets rather than an individual acknowledgement for each transmitted packet.In contrast to some of the existing techniques,the proposed mechanism is not dependent on the deployment of additional infrastructure like special Intrusion Detection System(IDS)nodes.The only overhead incurred is in the form of control packets exchanged for the reports request and the reports submission.
