Deep kernel mapping support vector machines have achieved good results in numerous tasks by mapping features from a low-dimensional space to a high-dimensional space and then using support vector machines for classifi...Deep kernel mapping support vector machines have achieved good results in numerous tasks by mapping features from a low-dimensional space to a high-dimensional space and then using support vector machines for classification.However,the depth kernel mapping support vector machine does not take into account the connection of different dimensional spaces and increases the model parameters.To further improve the recognition capability of deep kernel mapping support vector machines while reducing the number of model parameters,this paper proposes a framework of Lightweight Deep Convolutional Cross-Connected Kernel Mapping Support Vector Machines(LC-CKMSVM).The framework consists of a feature extraction module and a classification module.The feature extraction module first maps the data from low-dimensional to high-dimensional space by fusing the representations of different dimensional spaces through cross-connections;then,it uses depthwise separable convolution to replace part of the original convolution to reduce the number of parameters in the module;The classification module uses a soft margin support vector machine for classification.The results on 6 different visual datasets show that LC-CKMSVM obtains better classification accuracies on most cases than the other five models.展开更多
As the ITER (international thermonuclear experiment reactor ) project is being carried out further, original parties ( EU, JA, RF ) of ITER had accomplished their ITER TBM ( test blanket module ) design in 2001....As the ITER (international thermonuclear experiment reactor ) project is being carried out further, original parties ( EU, JA, RF ) of ITER had accomplished their ITER TBM ( test blanket module ) design in 2001. China joined the negotiation of 1TER project and planed to develop own TBM modules in 2003. A preliminary design description document ( DDD ) for the CH HCSB ( chinese helium-cooled solid breeder ) TBM module design had been completed at SWIP in 2004. A modified structure design based on the 2004 version had been carried out subsequently. Main modification of structure design is that the sub-module design is adopted instead of the previous integrative module design. The modified design enforces the reliability and the flexibility of TBM module structure. The integral TBM module consists of 9 sub-modules. The thermo-hydraulic analysis for sub-module is very important, because the sub-module as a relative independent module has the most basic function of the test blanket module, such as depositing heat, producing tritium, etc.展开更多
The AC/DC hybrid distribution network is one of the trends in distribution network development, which poses great challenges to the traditional distribution transformer. In this paper, a new topology suitable for AC/D...The AC/DC hybrid distribution network is one of the trends in distribution network development, which poses great challenges to the traditional distribution transformer. In this paper, a new topology suitable for AC/DC hybrid distribution network is put forward according to the demands of power grid, with advantages of accepting DG and DC loads, while clearing DC fault by blocking the clamping double sub-module(CDSM) of input stage. Then, this paper shows the typical structure of AC/DC distribution network that is hand in hand. Based on the new topology, this paper designs the control and modulation strategies of each stage, where the outer loop controller of input stage is emphasized for its twocontrol mode. At last, the rationality of new topology and the validity of control strategies are verified by the steady and dynamic state simulation. At the same time, the simulation results highlight the role of PET in energy regulation.展开更多
The characteristic of EDFA in WDM system is analyzed. The simulation system based on the architecture of the China Information Network (CAINONET) is introduced, and the influence of noise figure, gain unflatness and o...The characteristic of EDFA in WDM system is analyzed. The simulation system based on the architecture of the China Information Network (CAINONET) is introduced, and the influence of noise figure, gain unflatness and output power of EDFA on the BER performance and scale of network is investigated. Moreover, the influence of noise figure is studied with different crosstalk . Meanwhile, it is indicated that it is important to apply the "node isolation principle" in the optical network. The research results can provide the valuable reference for the practical construction of all optical network .展开更多
In the internet protocol(IP) over multi-granular optical switch network (IP/MG-OXC), the network node is a typical multilayer switch comprising several layers, the IP packet switching (PXC) layer, wavelength swi...In the internet protocol(IP) over multi-granular optical switch network (IP/MG-OXC), the network node is a typical multilayer switch comprising several layers, the IP packet switching (PXC) layer, wavelength switching (WXC) layer and fiber switching (FXC) layer. This network is capable of both IP layer grooming and wavelength grooming in a hierarchical manner. Resource provisioning in the multi-granular network paradigm is called hierarchical grooming problem. An integer linear programming (ILP) model is proposed to formulate the problem. An iterative heuristic approach is developed for solving the problem in large networks. Case study shows that IP/MG-OXC network is much more extendible and can significantly save the overall network cost as compared with IP over wavelength division multiplexing network.展开更多
In this paper, Optical Cross-Connection (OXC) induced crosstalk has been carefully analyzed for multiwavelength all-optical networks. Formulae are derived for calculating the crosstalk power of homowavelength crosstal...In this paper, Optical Cross-Connection (OXC) induced crosstalk has been carefully analyzed for multiwavelength all-optical networks. Formulae are derived for calculating the crosstalk power of homowavelength crosstalk and the total crosstalk at the receiver end. The results show that the optical switches induced crosstalk dominates over other crosstalk components of OXC, and the accumulated homowavelength crosstalk increases almost linearly with the increasing of the OXC number. At the receiver end , the heterowavelength crosstalk induced by the receiver optical filter has the same order as that of homowavelength crosstalk of OXC. The results of different optical components model are also discussed.展开更多
Based on the comparison of existing power flow controllers(PFC)in meshed HVDC grids,the full-bridge modular multilevel converter based PFC(MMPFC)is proposed.At first,the general branch current calculation method of me...Based on the comparison of existing power flow controllers(PFC)in meshed HVDC grids,the full-bridge modular multilevel converter based PFC(MMPFC)is proposed.At first,the general branch current calculation method of meshed HVDC grids with the PFC is presented,and then,the issue of over-voltage on the thyristor based PFC is described and analyzed.Through the analysis of different operating modes of the full-bridge sub-module,the mechanism of over-voltage ride through of the MMPFC is indicated.The control strategy of the MMPFC,which is used to control branch current and keep capacitor voltage balancing,is elaborated.Finally,the performance on current regulation,bidirectional operation and over-voltage ride through is simulated and verified in a built model with PSCAD/EMTDC.展开更多
The high-voltage direct current(HVDC)circuit breaker is becoming popular with the rapid development of the flexible HVDC grid for efficient DC fault ride-through purposes.This paper proposes a novel module for recipro...The high-voltage direct current(HVDC)circuit breaker is becoming popular with the rapid development of the flexible HVDC grid for efficient DC fault ride-through purposes.This paper proposes a novel module for reciprocating HVDC circuit breaker topology,whose branch connections are able to switch between series and parallel modes to limit the rising rate and interrupt the DC fault currents.Diode-bridge submodules(DBSMs)are used to compose the main branch for current interruption.Besides fault clearance,the proposed topology has the advantageous function of DC fault current limiting by employing DBSMs with bi-directional conduction capability.The topology can easily switch among branch connection modes through the assembled trans-valves,and their resistance and reactance are very small in the normal state when branches are in parallel and the values become promptly large in the transient state when the branches are series connected.With the modular design,it is easy to change the number of branches or sub-modules and the types of sub-modules to adapt to more specific needs.A 6-terminal modular multi-level converter(MMC)based HVDC grid is established in PSCAD/EMTDC,and various simulation scenarios are carried out to validate the proposed topology.展开更多
In view of the DC fault current isolation deficiency for the conventional half-bridge sub-module(HBSM)based modular multilevel converter(MMC),this paper presents an improved MMC topology.Both quasi reverse blocking su...In view of the DC fault current isolation deficiency for the conventional half-bridge sub-module(HBSM)based modular multilevel converter(MMC),this paper presents an improved MMC topology.Both quasi reverse blocking submodules(QRBSMs)and current limit modules(CLMs)are employed to improve the DC fault handling capability for HVDC applications.This paper analyzes such a new converter configuration and operation principles.Then the DC pole-to-pole short circuit fault is taken into consideration for further study,as well as the fault current blocking mechanism and quantitative relationship between system electrical stress and key parameters.To validate the feasibility of the proposed topology and fault protection theory,extensive simulation results are demonstrated.It is concluded that the QRB-MMC can effectively block the fault current under DC fault condition.In addition,CLMs play an important role in further accelerating fault current attenuation.Moreover,QRB-MMC employs the original control and modulation strategies under normal operation conditions;thus,it further reduces the complexity of industry design.展开更多
To reduce the probability of commutation failure(CF)of a line commutated converter based high-voltage direct current(LCC-HVDC)transmission,a DC chopper topology composed of power consumption sub-modules based on thyri...To reduce the probability of commutation failure(CF)of a line commutated converter based high-voltage direct current(LCC-HVDC)transmission,a DC chopper topology composed of power consumption sub-modules based on thyristor full-bridge module(TFB-PCSM)is proposed.Firstly,the mechanism of the proposed topology to mitigate CF is analyzed,and the working modes of TFB-PCSM in different operation states are introduced.Secondly,the coordinated control strategy between the proposed DC chopper and LCC-HVDC is designed,and the voltage-current stresses of the TFB-PCSMs are investigated.Finally,the ability to mitigate the CF issues and the fault recovery performance of LCC-HVDC system are studied in PSCAD/EMTDC.The results show that the probability of CF of LCC-HVDC is significantly reduced,and the performances of fault recovery are effectively improved by the proposed DC chopper.展开更多
An ATM ring switching testbed is proposed in this paper. Two practical applications for the ATMring exchange are aimed, one is used ai ATM LAM/MAN, another is for rural local ATM exchange. A dis-tributed swithching an...An ATM ring switching testbed is proposed in this paper. Two practical applications for the ATMring exchange are aimed, one is used ai ATM LAM/MAN, another is for rural local ATM exchange. A dis-tributed swithching and control architecture is designed. together with a modular and flexible hardware and soft-ware structure which permits a rapid and easy introduction and testing of new, services. Hierarchical VP and VCswitching is organized, three AALs (AAL1, AAL4 & AAL5) are supported to provide conaretion-oriented andconnectionless services Broadcasting, multicasting and multi-conferencing functions are achieved at no extra cost,and imerworking with the existing network is emphasized. The constucticon of ring access node is described. As anexample a PDH-ATM interface is given.展开更多
基金This work is supported by the National Natural Science Foundation of China(61806013,61876010,61906005,62166002)General project of Science and Technology Plan of Beijing Municipal Education Commission(KM202110005028)+1 种基金Project of Interdisciplinary Research Institute of Beijing University of Technology(2021020101)International Research Cooperation Seed Fund of Beijing University of Technology(2021A01).
文摘Deep kernel mapping support vector machines have achieved good results in numerous tasks by mapping features from a low-dimensional space to a high-dimensional space and then using support vector machines for classification.However,the depth kernel mapping support vector machine does not take into account the connection of different dimensional spaces and increases the model parameters.To further improve the recognition capability of deep kernel mapping support vector machines while reducing the number of model parameters,this paper proposes a framework of Lightweight Deep Convolutional Cross-Connected Kernel Mapping Support Vector Machines(LC-CKMSVM).The framework consists of a feature extraction module and a classification module.The feature extraction module first maps the data from low-dimensional to high-dimensional space by fusing the representations of different dimensional spaces through cross-connections;then,it uses depthwise separable convolution to replace part of the original convolution to reduce the number of parameters in the module;The classification module uses a soft margin support vector machine for classification.The results on 6 different visual datasets show that LC-CKMSVM obtains better classification accuracies on most cases than the other five models.
文摘As the ITER (international thermonuclear experiment reactor ) project is being carried out further, original parties ( EU, JA, RF ) of ITER had accomplished their ITER TBM ( test blanket module ) design in 2001. China joined the negotiation of 1TER project and planed to develop own TBM modules in 2003. A preliminary design description document ( DDD ) for the CH HCSB ( chinese helium-cooled solid breeder ) TBM module design had been completed at SWIP in 2004. A modified structure design based on the 2004 version had been carried out subsequently. Main modification of structure design is that the sub-module design is adopted instead of the previous integrative module design. The modified design enforces the reliability and the flexibility of TBM module structure. The integral TBM module consists of 9 sub-modules. The thermo-hydraulic analysis for sub-module is very important, because the sub-module as a relative independent module has the most basic function of the test blanket module, such as depositing heat, producing tritium, etc.
基金supported by National Key Research and Development Program of China (2016YFB0900500,2017YFB0903100)the State Grid Science and Technology Project (SGRI-DL-F1-51-011)
文摘The AC/DC hybrid distribution network is one of the trends in distribution network development, which poses great challenges to the traditional distribution transformer. In this paper, a new topology suitable for AC/DC hybrid distribution network is put forward according to the demands of power grid, with advantages of accepting DG and DC loads, while clearing DC fault by blocking the clamping double sub-module(CDSM) of input stage. Then, this paper shows the typical structure of AC/DC distribution network that is hand in hand. Based on the new topology, this paper designs the control and modulation strategies of each stage, where the outer loop controller of input stage is emphasized for its twocontrol mode. At last, the rationality of new topology and the validity of control strategies are verified by the steady and dynamic state simulation. At the same time, the simulation results highlight the role of PET in energy regulation.
文摘The characteristic of EDFA in WDM system is analyzed. The simulation system based on the architecture of the China Information Network (CAINONET) is introduced, and the influence of noise figure, gain unflatness and output power of EDFA on the BER performance and scale of network is investigated. Moreover, the influence of noise figure is studied with different crosstalk . Meanwhile, it is indicated that it is important to apply the "node isolation principle" in the optical network. The research results can provide the valuable reference for the practical construction of all optical network .
基金Sponsored by Agency for Singapore Technology and Advance Research(RGM01/16)
文摘In the internet protocol(IP) over multi-granular optical switch network (IP/MG-OXC), the network node is a typical multilayer switch comprising several layers, the IP packet switching (PXC) layer, wavelength switching (WXC) layer and fiber switching (FXC) layer. This network is capable of both IP layer grooming and wavelength grooming in a hierarchical manner. Resource provisioning in the multi-granular network paradigm is called hierarchical grooming problem. An integer linear programming (ILP) model is proposed to formulate the problem. An iterative heuristic approach is developed for solving the problem in large networks. Case study shows that IP/MG-OXC network is much more extendible and can significantly save the overall network cost as compared with IP over wavelength division multiplexing network.
文摘In this paper, Optical Cross-Connection (OXC) induced crosstalk has been carefully analyzed for multiwavelength all-optical networks. Formulae are derived for calculating the crosstalk power of homowavelength crosstalk and the total crosstalk at the receiver end. The results show that the optical switches induced crosstalk dominates over other crosstalk components of OXC, and the accumulated homowavelength crosstalk increases almost linearly with the increasing of the OXC number. At the receiver end , the heterowavelength crosstalk induced by the receiver optical filter has the same order as that of homowavelength crosstalk of OXC. The results of different optical components model are also discussed.
基金supported by the National High Technology Research and Development Program of China("863"Program)(Grant No.2012AA050205)
文摘Based on the comparison of existing power flow controllers(PFC)in meshed HVDC grids,the full-bridge modular multilevel converter based PFC(MMPFC)is proposed.At first,the general branch current calculation method of meshed HVDC grids with the PFC is presented,and then,the issue of over-voltage on the thyristor based PFC is described and analyzed.Through the analysis of different operating modes of the full-bridge sub-module,the mechanism of over-voltage ride through of the MMPFC is indicated.The control strategy of the MMPFC,which is used to control branch current and keep capacitor voltage balancing,is elaborated.Finally,the performance on current regulation,bidirectional operation and over-voltage ride through is simulated and verified in a built model with PSCAD/EMTDC.
基金supported by the National Key R&D Program of China(No.2018YFB0904600)the National Natural Science Foundation of China(No.51777072)
文摘The high-voltage direct current(HVDC)circuit breaker is becoming popular with the rapid development of the flexible HVDC grid for efficient DC fault ride-through purposes.This paper proposes a novel module for reciprocating HVDC circuit breaker topology,whose branch connections are able to switch between series and parallel modes to limit the rising rate and interrupt the DC fault currents.Diode-bridge submodules(DBSMs)are used to compose the main branch for current interruption.Besides fault clearance,the proposed topology has the advantageous function of DC fault current limiting by employing DBSMs with bi-directional conduction capability.The topology can easily switch among branch connection modes through the assembled trans-valves,and their resistance and reactance are very small in the normal state when branches are in parallel and the values become promptly large in the transient state when the branches are series connected.With the modular design,it is easy to change the number of branches or sub-modules and the types of sub-modules to adapt to more specific needs.A 6-terminal modular multi-level converter(MMC)based HVDC grid is established in PSCAD/EMTDC,and various simulation scenarios are carried out to validate the proposed topology.
基金supported in part by the State Key Laboratory of Large Electric Drive System and Equipment Technology(No.SKLLDJ042016005)in part by Open Fund of State Key Laboratory of Operation and Control of Renewable Energy&Storage Systemsin part by the National Key Research and Development Program of China(2016YFE0131700).
文摘In view of the DC fault current isolation deficiency for the conventional half-bridge sub-module(HBSM)based modular multilevel converter(MMC),this paper presents an improved MMC topology.Both quasi reverse blocking submodules(QRBSMs)and current limit modules(CLMs)are employed to improve the DC fault handling capability for HVDC applications.This paper analyzes such a new converter configuration and operation principles.Then the DC pole-to-pole short circuit fault is taken into consideration for further study,as well as the fault current blocking mechanism and quantitative relationship between system electrical stress and key parameters.To validate the feasibility of the proposed topology and fault protection theory,extensive simulation results are demonstrated.It is concluded that the QRB-MMC can effectively block the fault current under DC fault condition.In addition,CLMs play an important role in further accelerating fault current attenuation.Moreover,QRB-MMC employs the original control and modulation strategies under normal operation conditions;thus,it further reduces the complexity of industry design.
基金supported by National Natural Science Foundation of China(No.51877077)。
文摘To reduce the probability of commutation failure(CF)of a line commutated converter based high-voltage direct current(LCC-HVDC)transmission,a DC chopper topology composed of power consumption sub-modules based on thyristor full-bridge module(TFB-PCSM)is proposed.Firstly,the mechanism of the proposed topology to mitigate CF is analyzed,and the working modes of TFB-PCSM in different operation states are introduced.Secondly,the coordinated control strategy between the proposed DC chopper and LCC-HVDC is designed,and the voltage-current stresses of the TFB-PCSMs are investigated.Finally,the ability to mitigate the CF issues and the fault recovery performance of LCC-HVDC system are studied in PSCAD/EMTDC.The results show that the probability of CF of LCC-HVDC is significantly reduced,and the performances of fault recovery are effectively improved by the proposed DC chopper.
文摘An ATM ring switching testbed is proposed in this paper. Two practical applications for the ATMring exchange are aimed, one is used ai ATM LAM/MAN, another is for rural local ATM exchange. A dis-tributed swithching and control architecture is designed. together with a modular and flexible hardware and soft-ware structure which permits a rapid and easy introduction and testing of new, services. Hierarchical VP and VCswitching is organized, three AALs (AAL1, AAL4 & AAL5) are supported to provide conaretion-oriented andconnectionless services Broadcasting, multicasting and multi-conferencing functions are achieved at no extra cost,and imerworking with the existing network is emphasized. The constucticon of ring access node is described. As anexample a PDH-ATM interface is given.