When controling the signal of highway-rail level crossings in the port area,the multi-objective signal optimization model is not applicable due to the cross effect of roads and railways and the priority of incoming ve...When controling the signal of highway-rail level crossings in the port area,the multi-objective signal optimization model is not applicable due to the cross effect of roads and railways and the priority of incoming vehicles.Therefore,in order to ensure that the inbound truck fleet enters the port directly without being affected by the train when passing through the highway-rail level crossing in the port area,the queuing of vehicles in front of the port needs to be reduced,and the priority should be given to the inbound trucks.Based on the idea of priority on key lanes,this study relies on speed guidance information to guide the fleet to shift reasonably,postpone or early arrive at the railway gate.At the same time,the optimization goal is to minimize the delays at intersections,the number of stops,and the vehicle exhaust emissions.The measured data of road-rail level crossings in Dayaowan Port area of Dalian were selected,and it was re-developed under the VISSIM environment by serial interface to realize signal optimization control under vehicle speed guidance.The original timing plan,multi-objective timing optimization plan and key lanes priority are given to the optimization scheme for simulation experiments.The results show that the multi-objective optimization scheme and the optimization scheme under the priority of key lanes can generally improve the traffic capacity of road-rail level crossings.Compared with the original plan,the optimization plan under the priority of key lanes reduces the delay by 33.3%,the number of stops is reduced by 25%,and the vehicle exhaust emissions are reduced by 31.3%.It proves the effectiveness of the optimization scheme for highway-rail level crossings in the port area under the priority of key lanes,and it is more suitable for highway-rail level crossings.展开更多
In the structural design of tall buildings, peak factors have been widely used to predict mean extreme responses of tall buildings under wind excitations. Vanmarcke＇s peak factor is directly related to an explicit me...In the structural design of tall buildings, peak factors have been widely used to predict mean extreme responses of tall buildings under wind excitations. Vanmarcke＇s peak factor is directly related to an explicit measure of structural reliability against a Gaussian response process. We review the use of this factor for time-variant reliability design by comparing it to the conven- tional Davenport＇s peak factor. Based on the asymptotic theory of statistical extremes, a new closed-form peak factor, the so-called Gamma peak factor, can be obtained for a non-Gaussian resultant response characterized by a Rayleigh distribution process. Using the Gamma peak factor, a combined peak factor method was developed for predicting the expected maximum resultant responses of a building undergoing lateral-torsional vibration. The effects of the standard deviation ratio of two sway components and the inter-component correlation on the evaluation of peak resultant response were also investigated. Utilizing wind tunnel data derived from synchronous multi-pressure measurements, we carried out a wind-induced time history response analysis of the Common- wealth Advisory Aeronautical Research Council （CAARC） standard tall building to validate the applicability of the Gamma peak factor to the prediction of the peak resultant acceleration. Results from the building example indicated that the use of the Gamma peak factor enables accurate predictions to be made of the mean extreme resultant acceleration responses for dynamic service- ability performance design of modem tall buildings.展开更多
An analytical method is developed to study the two-mode quantum Rabi model.For certain specific parameter conditions,especially for the resonant conditions,we obtain an infinite number of the exact solutions of the ei...An analytical method is developed to study the two-mode quantum Rabi model.For certain specific parameter conditions,especially for the resonant conditions,we obtain an infinite number of the exact solutions of the eigenfunctions and associated energies.It is shown that there exist new types of the exact energies which do not correspond to the level-crossings.Our analytical method may find applications in some related models.展开更多
Amplify-and-forward channels in cooperative networks provide a promising improvement in the network coverage and system throughput. Under line-of-sight (LOS) propagation conditions in such cooperative networks, the ov...Amplify-and-forward channels in cooperative networks provide a promising improvement in the network coverage and system throughput. Under line-of-sight (LOS) propagation conditions in such cooperative networks, the overall fading channel can be modeled by a double Rice process. In this article, we have stud-ied the statistical properties of the capacity of double Rice fading channels. We have derived the analytical expressions for the probability density function (PDF), cumulative distribution function (CDF), level- crossing rate (LCR), and average duration of fades (ADF) of the channel capacity. The obtained results are studied for different values of the amplitudes of the LOS components in the two links of double Rice fading channels. It has been observed that the statistics of the capacity of double Rice fading channels are quite dif-ferent from those of double Rayleigh and classical Rice fading channels. Moreover, the presence of an LOS component in any of the two links increases the mean channel capacity and the LCR of the channel capacity. The validity of the theoretical results is confirmed by simulations. The results presented in this article can be very useful for communication system designers to optimize the performance of cooperative networks in wireless communication systems.展开更多
The concept of"SU(3)analysis"is proposed for the B(E2)anomaly based on various mechanisms reported recently.The B(E2)anomaly is analyzed in the SU(3)symmetry limit.According to the results of the analysis,th...The concept of"SU(3)analysis"is proposed for the B(E2)anomaly based on various mechanisms reported recently.The B(E2)anomaly is analyzed in the SU(3)symmetry limit.According to the results of the analysis,the SU(3)third-order interaction[L×Q×L]^((0))can generate the level-crossing phenomenon for any mechanism,which is vital for the emergence of the B(E2)anomaly.Thus,this anomaly is found to be related with the SU(3)symmetry.The B(E2)anomaly in ^(168)Os is also analyzed.展开更多
基金the Research on Key Technologies and Equipment for Transportation Infrastructure Construction Safety(No.2017YFC0805309)。
文摘When controling the signal of highway-rail level crossings in the port area,the multi-objective signal optimization model is not applicable due to the cross effect of roads and railways and the priority of incoming vehicles.Therefore,in order to ensure that the inbound truck fleet enters the port directly without being affected by the train when passing through the highway-rail level crossing in the port area,the queuing of vehicles in front of the port needs to be reduced,and the priority should be given to the inbound trucks.Based on the idea of priority on key lanes,this study relies on speed guidance information to guide the fleet to shift reasonably,postpone or early arrive at the railway gate.At the same time,the optimization goal is to minimize the delays at intersections,the number of stops,and the vehicle exhaust emissions.The measured data of road-rail level crossings in Dayaowan Port area of Dalian were selected,and it was re-developed under the VISSIM environment by serial interface to realize signal optimization control under vehicle speed guidance.The original timing plan,multi-objective timing optimization plan and key lanes priority are given to the optimization scheme for simulation experiments.The results show that the multi-objective optimization scheme and the optimization scheme under the priority of key lanes can generally improve the traffic capacity of road-rail level crossings.Compared with the original plan,the optimization plan under the priority of key lanes reduces the delay by 33.3%,the number of stops is reduced by 25%,and the vehicle exhaust emissions are reduced by 31.3%.It proves the effectiveness of the optimization scheme for highway-rail level crossings in the port area under the priority of key lanes,and it is more suitable for highway-rail level crossings.
基金Project supported by the National Natural Science Foundation of China (No. 51008275)the China Postdoctoral Science Foundation (No.201104736)
文摘In the structural design of tall buildings, peak factors have been widely used to predict mean extreme responses of tall buildings under wind excitations. Vanmarcke＇s peak factor is directly related to an explicit measure of structural reliability against a Gaussian response process. We review the use of this factor for time-variant reliability design by comparing it to the conven- tional Davenport＇s peak factor. Based on the asymptotic theory of statistical extremes, a new closed-form peak factor, the so-called Gamma peak factor, can be obtained for a non-Gaussian resultant response characterized by a Rayleigh distribution process. Using the Gamma peak factor, a combined peak factor method was developed for predicting the expected maximum resultant responses of a building undergoing lateral-torsional vibration. The effects of the standard deviation ratio of two sway components and the inter-component correlation on the evaluation of peak resultant response were also investigated. Utilizing wind tunnel data derived from synchronous multi-pressure measurements, we carried out a wind-induced time history response analysis of the Common- wealth Advisory Aeronautical Research Council （CAARC） standard tall building to validate the applicability of the Gamma peak factor to the prediction of the peak resultant acceleration. Results from the building example indicated that the use of the Gamma peak factor enables accurate predictions to be made of the mean extreme resultant acceleration responses for dynamic service- ability performance design of modem tall buildings.
基金Supported by the National Natural Science Foundation of China under Grant No.11965011。
文摘An analytical method is developed to study the two-mode quantum Rabi model.For certain specific parameter conditions,especially for the resonant conditions,we obtain an infinite number of the exact solutions of the eigenfunctions and associated energies.It is shown that there exist new types of the exact energies which do not correspond to the level-crossings.Our analytical method may find applications in some related models.
文摘Amplify-and-forward channels in cooperative networks provide a promising improvement in the network coverage and system throughput. Under line-of-sight (LOS) propagation conditions in such cooperative networks, the overall fading channel can be modeled by a double Rice process. In this article, we have stud-ied the statistical properties of the capacity of double Rice fading channels. We have derived the analytical expressions for the probability density function (PDF), cumulative distribution function (CDF), level- crossing rate (LCR), and average duration of fades (ADF) of the channel capacity. The obtained results are studied for different values of the amplitudes of the LOS components in the two links of double Rice fading channels. It has been observed that the statistics of the capacity of double Rice fading channels are quite dif-ferent from those of double Rayleigh and classical Rice fading channels. Moreover, the presence of an LOS component in any of the two links increases the mean channel capacity and the LCR of the channel capacity. The validity of the theoretical results is confirmed by simulations. The results presented in this article can be very useful for communication system designers to optimize the performance of cooperative networks in wireless communication systems.
文摘The concept of"SU(3)analysis"is proposed for the B(E2)anomaly based on various mechanisms reported recently.The B(E2)anomaly is analyzed in the SU(3)symmetry limit.According to the results of the analysis,the SU(3)third-order interaction[L×Q×L]^((0))can generate the level-crossing phenomenon for any mechanism,which is vital for the emergence of the B(E2)anomaly.Thus,this anomaly is found to be related with the SU(3)symmetry.The B(E2)anomaly in ^(168)Os is also analyzed.
