This paper investigates the cross-correlation characteristics of large-scale parameters(LSPs) and small-scale fading(SSF) for high-speed railway(HSR) multilink propagation scenarios, based on realistic measurements co...This paper investigates the cross-correlation characteristics of large-scale parameters(LSPs) and small-scale fading(SSF) for high-speed railway(HSR) multilink propagation scenarios, based on realistic measurements conducted on Beijing to Tianjin HSR line in China. A long-term evolution-based channel sounding system is utilized in the measurements to obtain the channel data. By applying a proposed time-delay based dynamic partition method, multi-link channel impulse responses are extracted from the raw channel data. Then, the statistical results of LSPs, including shadow fading, K-factor, and root-mean-square delay spread are derived and the cross-correlation coefficients of these LPSs are calculated. Moreover, the SSF spatial correlation and cross-correlation of SSF are analyzed. These results can be used to exploit multi-link channel model and to optimize the next-generation HSR communication system.展开更多
Coordinated scheduling of multimode plays a pivotal role in the rapid gathering and dissipating of passengers in transport hubs. Based on the survey data, the whole-day reaching time distribution at transfer points of...Coordinated scheduling of multimode plays a pivotal role in the rapid gathering and dissipating of passengers in transport hubs. Based on the survey data, the whole-day reaching time distribution at transfer points of passengers from the dominant mode to the connecting mode was achieved. A GI/M K/1 bulk service queuing system was constituted by putting the passengers' reaching time distribution as the input and the connecting mode as the service institution. Through queuing theory, the relationship between average queuing length under steady-state and headway of the connecting mode was achieved. By putting the minimum total cost of system as optimization objective, the headway as decision variable, a coordinated scheduling model of multimode in intermodal transit hubs was established. At last, a dynamic scheduling strategy was generated to cope with the unexpected changes of the dominant mode. The instance analysis indicates that this model can significantly reduce passengers' queuing time by approximately 17% with no apparently increase in departure frequency, which provides a useful solution for the coordinated scheduling of different transport modes in hubs.展开更多
In view of the universality of the parallel connection of solar cells and their mismatch problem, in the present paper, we select two shunt solar cells (connected in parallel) as our research object, and use the equiv...In view of the universality of the parallel connection of solar cells and their mismatch problem, in the present paper, we select two shunt solar cells (connected in parallel) as our research object, and use the equivalent one-diode circuit of the solar cell and the analysis of the two-body model. At first, the equations of current and voltage are deduced from the related electrical laws and the circuit diagram of the two solar cells connected in parallel. Then, according to the experimentally measured data of typical single-crystalline silicon solar cells (125 mm×125 mm), we select the appropriate simulation parameters. Following this, by using the photo-generated current, the shunt resistance, and the serial resistance of one of the shunt solar cells and the load resistance as independent variables, in turn, the changing characteristics of each branch current in the two shunt solar cells are numerically discussed and analyzed for these four cases for the first time. At the same time, we provide a simple physical explanation for the modeling results. Our analyses show that these parameters have different impacts on the internal currents of solar cells connected in parallel. These results provide a reference to solve the problem of connecting solar cells and to develop higher efficiency solar cells and systems. Meanwhile, the results will contribute to a better comprehension of the reasons for efficiency loss of solar cells and systems, and deepen the understanding of the electrical of solar cells behavior for high performance photovoltaic applications.展开更多
基金supported by the Beijing Municipal Natural Science Foundation under Grant 4174102the National Natural Science Foundation of China under Grant 61701017+1 种基金the Open Research Fund through the National Mobile Communications Research Laboratory, Southeast University, under Grant 2018D11the Fundamental Research Funds for the Central Universities under Grant 2018JBM003
文摘This paper investigates the cross-correlation characteristics of large-scale parameters(LSPs) and small-scale fading(SSF) for high-speed railway(HSR) multilink propagation scenarios, based on realistic measurements conducted on Beijing to Tianjin HSR line in China. A long-term evolution-based channel sounding system is utilized in the measurements to obtain the channel data. By applying a proposed time-delay based dynamic partition method, multi-link channel impulse responses are extracted from the raw channel data. Then, the statistical results of LSPs, including shadow fading, K-factor, and root-mean-square delay spread are derived and the cross-correlation coefficients of these LPSs are calculated. Moreover, the SSF spatial correlation and cross-correlation of SSF are analyzed. These results can be used to exploit multi-link channel model and to optimize the next-generation HSR communication system.
基金Projects(51278221,51378076)supported by the National Natural Science Foundation of China
文摘Coordinated scheduling of multimode plays a pivotal role in the rapid gathering and dissipating of passengers in transport hubs. Based on the survey data, the whole-day reaching time distribution at transfer points of passengers from the dominant mode to the connecting mode was achieved. A GI/M K/1 bulk service queuing system was constituted by putting the passengers' reaching time distribution as the input and the connecting mode as the service institution. Through queuing theory, the relationship between average queuing length under steady-state and headway of the connecting mode was achieved. By putting the minimum total cost of system as optimization objective, the headway as decision variable, a coordinated scheduling model of multimode in intermodal transit hubs was established. At last, a dynamic scheduling strategy was generated to cope with the unexpected changes of the dominant mode. The instance analysis indicates that this model can significantly reduce passengers' queuing time by approximately 17% with no apparently increase in departure frequency, which provides a useful solution for the coordinated scheduling of different transport modes in hubs.
基金supported by the National Natural Science Foundation of China (Grant No. 51561031)the Natural Science Foundation of Guangxi Province (Grant No. 2015GXNSFBA139240)+1 种基金Open Foundation of Guangxi Colleges and Universities Key Laboratory of Complex System Optimization and Large Data Processing (Grant No. 2015CSOBD0102)the Highlevel Personnel Scientific Research Funds of Yulin Normal University (Grant No. G20150001)
文摘In view of the universality of the parallel connection of solar cells and their mismatch problem, in the present paper, we select two shunt solar cells (connected in parallel) as our research object, and use the equivalent one-diode circuit of the solar cell and the analysis of the two-body model. At first, the equations of current and voltage are deduced from the related electrical laws and the circuit diagram of the two solar cells connected in parallel. Then, according to the experimentally measured data of typical single-crystalline silicon solar cells (125 mm×125 mm), we select the appropriate simulation parameters. Following this, by using the photo-generated current, the shunt resistance, and the serial resistance of one of the shunt solar cells and the load resistance as independent variables, in turn, the changing characteristics of each branch current in the two shunt solar cells are numerically discussed and analyzed for these four cases for the first time. At the same time, we provide a simple physical explanation for the modeling results. Our analyses show that these parameters have different impacts on the internal currents of solar cells connected in parallel. These results provide a reference to solve the problem of connecting solar cells and to develop higher efficiency solar cells and systems. Meanwhile, the results will contribute to a better comprehension of the reasons for efficiency loss of solar cells and systems, and deepen the understanding of the electrical of solar cells behavior for high performance photovoltaic applications.
