Reasonable distribution of braking force is a factor for a smooth,safe,and comfortable braking of trains.A dynamic optimal allocation strategy of electric-air braking force is proposed in this paper to solve the probl...Reasonable distribution of braking force is a factor for a smooth,safe,and comfortable braking of trains.A dynamic optimal allocation strategy of electric-air braking force is proposed in this paper to solve the problem of the lack of consideration of adhesion difference of train wheelsets in the existing high-speed train electric-air braking force optimal allocation strategies.In this method,the braking strategy gives priority to the use of electric braking force.The force model of a single train in the braking process is analyzed to calculate the change of adhesion between the wheel and rail of each wheelset after axle load transfer,and then the adhesion of the train is estimated in real time.Next,with the goal of maximizing the total adhesion utilization ratio of trailer/motor vehicles,a linear programming distribution function is constructed.The proportional coefficient of adhesion utilization ratio of each train and the application upper limit of braking force in the function is updated according to the change time point of wheelset adhesion.Finally,the braking force is dynamically allocated.The simulation results of Matlab/Simulink show that the proposed algorithm not only uses the different adhesion limits of each trailer to reduce the total amount of braking force undertaken by the motor vehicle,but also considers the adhesion difference of each wheelset.The strategy can effectively reduce the risk and time of motor vehicles during the braking process and improve the stability of the train braking.展开更多
Fueled by the explosive growth of ultra-low-latency and real-time applications with specific computing and network performance requirements,the computing force network(CFN)has become a hot research subject.The primary...Fueled by the explosive growth of ultra-low-latency and real-time applications with specific computing and network performance requirements,the computing force network(CFN)has become a hot research subject.The primary CFN challenge is to leverage network resources and computing resources.Although recent advances in deep reinforcement learning(DRL)have brought significant improvement in network optimization,these methods still suffer from topology changes and fail to generalize for those topologies not seen in training.This paper proposes a graph neural network(GNN)based DRL framework to accommodate network trafic and computing resources jointly and efficiently.By taking advantage of the generalization capability in GNN,the proposed method can operate over variable topologies and obtain higher performance than the other DRL methods.展开更多
A multi-antenna multiple relay (MAMR) network is considered and a variation of two-hop zero-forcing amplify-forward relaying method is proposed. Deploying ZF method together with application of diagonal power allocati...A multi-antenna multiple relay (MAMR) network is considered and a variation of two-hop zero-forcing amplify-forward relaying method is proposed. Deploying ZF method together with application of diagonal power allocation matrices at the relays, it is shown that the overall MAMR network is simplified to M independent single antenna multiple relay (SAMR) networks, where M is the number of source and destination antennas. This enables to incorporate network beamforming proposed for SAMR networks. Accordingly, using the BER as the performance metric, we present simulation results to show the proposed approach outperforms the common ZF method addressed in the literature.展开更多
To minimize the overall transmit power while maintaining a constant data rate and target BER, a downlink adaptive resource allocation algorithm with jointing the exclusive manner and the shared manner is proposed for ...To minimize the overall transmit power while maintaining a constant data rate and target BER, a downlink adaptive resource allocation algorithm with jointing the exclusive manner and the shared manner is proposed for multiuser MIMO-OFDM system in correlated channels. The algorithm allocates all the subcarriers to different users according to their spatial correlations. The users with high spatial correlation are allocated in the same group and the exclusive manner is applied. The shared manner with an improved null broadening method, which improves the performance of co-channel interference （CCI） suppression and decreases the number of transmit antennas required, is applied between the different group users. As the user＇s direction of departure （DOD） changes very slowly, a looking up table method is used to reduce the computational complexity. The simulation results show that despite the angle spread of DOD, when compared with the exclusive manner, the proposed algorithm improves the spectral efficiency, and when compared with the TDMA-ZF （zero forcing） shared manner, the proposed algorithm decreases the total transmit power by at least 1 dB.展开更多
This paper aims to investigate the effects of labor allocation distortions and various levels of distortion-free labor allocation on social output in China's primary,secondary and tertiary industries.Theoretical m...This paper aims to investigate the effects of labor allocation distortions and various levels of distortion-free labor allocation on social output in China's primary,secondary and tertiary industries.Theoretical model creation and empirical study have led us to the following findings:the quantity of workforce in China's primary industry exceeds the quantity of workforce under the scenario of distortion-free labor allocation and the same is generally true for China's tertiary industry.However,the quantity of labor allocation in secondary industry is significantly below the level of distortion-free allocation but the share of allocation distortion overall tends to decline.Labor allocation distortions for various sectors are mainly caused by intra-sectoral allocation distortions and sectoral wage differences,of which the effect of internal distortion factor is the most obvious.In terms of total output,the eliminations of total distortion,wage difference distortion and internal allocation distortion will all cause total social output to exceed original output,and labor reallocation accompanying capital change will not only bring about a further increase of output but may offset the defects of limited potentials of labor resources reallocation.Growth rates with the eliminations of wage difference distortion,internal allocation distortion and superimposed factor can basically explain for the growth rates with the elimination of all distortions.Given this background,it is necessary to take effective measures at an early date to reduce China s labor allocation distortions and improve overall economic efficiency.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.62173137,52172403,62303178).
文摘Reasonable distribution of braking force is a factor for a smooth,safe,and comfortable braking of trains.A dynamic optimal allocation strategy of electric-air braking force is proposed in this paper to solve the problem of the lack of consideration of adhesion difference of train wheelsets in the existing high-speed train electric-air braking force optimal allocation strategies.In this method,the braking strategy gives priority to the use of electric braking force.The force model of a single train in the braking process is analyzed to calculate the change of adhesion between the wheel and rail of each wheelset after axle load transfer,and then the adhesion of the train is estimated in real time.Next,with the goal of maximizing the total adhesion utilization ratio of trailer/motor vehicles,a linear programming distribution function is constructed.The proportional coefficient of adhesion utilization ratio of each train and the application upper limit of braking force in the function is updated according to the change time point of wheelset adhesion.Finally,the braking force is dynamically allocated.The simulation results of Matlab/Simulink show that the proposed algorithm not only uses the different adhesion limits of each trailer to reduce the total amount of braking force undertaken by the motor vehicle,but also considers the adhesion difference of each wheelset.The strategy can effectively reduce the risk and time of motor vehicles during the braking process and improve the stability of the train braking.
基金supported by the Beijing University of Posts and Telecommunications-China Mobile Research Institute Joint Innovation Center。
文摘Fueled by the explosive growth of ultra-low-latency and real-time applications with specific computing and network performance requirements,the computing force network(CFN)has become a hot research subject.The primary CFN challenge is to leverage network resources and computing resources.Although recent advances in deep reinforcement learning(DRL)have brought significant improvement in network optimization,these methods still suffer from topology changes and fail to generalize for those topologies not seen in training.This paper proposes a graph neural network(GNN)based DRL framework to accommodate network trafic and computing resources jointly and efficiently.By taking advantage of the generalization capability in GNN,the proposed method can operate over variable topologies and obtain higher performance than the other DRL methods.
文摘A multi-antenna multiple relay (MAMR) network is considered and a variation of two-hop zero-forcing amplify-forward relaying method is proposed. Deploying ZF method together with application of diagonal power allocation matrices at the relays, it is shown that the overall MAMR network is simplified to M independent single antenna multiple relay (SAMR) networks, where M is the number of source and destination antennas. This enables to incorporate network beamforming proposed for SAMR networks. Accordingly, using the BER as the performance metric, we present simulation results to show the proposed approach outperforms the common ZF method addressed in the literature.
基金the National Natural Science Foundation of China (60572039 60432040)
文摘To minimize the overall transmit power while maintaining a constant data rate and target BER, a downlink adaptive resource allocation algorithm with jointing the exclusive manner and the shared manner is proposed for multiuser MIMO-OFDM system in correlated channels. The algorithm allocates all the subcarriers to different users according to their spatial correlations. The users with high spatial correlation are allocated in the same group and the exclusive manner is applied. The shared manner with an improved null broadening method, which improves the performance of co-channel interference （CCI） suppression and decreases the number of transmit antennas required, is applied between the different group users. As the user＇s direction of departure （DOD） changes very slowly, a looking up table method is used to reduce the computational complexity. The simulation results show that despite the angle spread of DOD, when compared with the exclusive manner, the proposed algorithm improves the spectral efficiency, and when compared with the TDMA-ZF （zero forcing） shared manner, the proposed algorithm decreases the total transmit power by at least 1 dB.
基金funded by National Social Sciences Foundation Program:Empirical Analysis and Countermeasures of Income Distribution Imbalances for Corporate Average Employees Based on Quality and Efficiency(Approval No.13BJY037)
文摘This paper aims to investigate the effects of labor allocation distortions and various levels of distortion-free labor allocation on social output in China's primary,secondary and tertiary industries.Theoretical model creation and empirical study have led us to the following findings:the quantity of workforce in China's primary industry exceeds the quantity of workforce under the scenario of distortion-free labor allocation and the same is generally true for China's tertiary industry.However,the quantity of labor allocation in secondary industry is significantly below the level of distortion-free allocation but the share of allocation distortion overall tends to decline.Labor allocation distortions for various sectors are mainly caused by intra-sectoral allocation distortions and sectoral wage differences,of which the effect of internal distortion factor is the most obvious.In terms of total output,the eliminations of total distortion,wage difference distortion and internal allocation distortion will all cause total social output to exceed original output,and labor reallocation accompanying capital change will not only bring about a further increase of output but may offset the defects of limited potentials of labor resources reallocation.Growth rates with the eliminations of wage difference distortion,internal allocation distortion and superimposed factor can basically explain for the growth rates with the elimination of all distortions.Given this background,it is necessary to take effective measures at an early date to reduce China s labor allocation distortions and improve overall economic efficiency.
