Analysis of dynamic features of pedestrian flows is one of the most exciting topics in pedestrian dynamics. This paper focuses on the effect of homogeneity and heterogeneity in three parameters of the social force mod...Analysis of dynamic features of pedestrian flows is one of the most exciting topics in pedestrian dynamics. This paper focuses on the effect of homogeneity and heterogeneity in three parameters of the social force model, namely desired velocity, reaction time, and body size, on the moving dynamics of bidirectional pedestrian flows in the corridors. The speed and its deviation in free flows are investigated. Simulation results show that the homogeneous higher desired speed which is less than a critical threshold, shorter reaction time or smaller body size results in higher speed of flows. The free dynamics is more sensitive to the heterogeneity in desired speed than that in reaction time or in body size. In particular, an inner lane formation is observed in normal lanes. Furthermore, the breakdown probability and the start time of breakdown are focused on. This study reveals that the sizes of homogeneous desired speed, reaction time or body size play more important roles in affecting the breakdown than the heterogeneities in these three parameters do.展开更多
This paper focuses on a two-dimensional bidirectional pedestrian flow model which involves the next-nearest-neighbor effect. The stability condition and the Korteweg-de Vries （KdV） equation are derived to describe t...This paper focuses on a two-dimensional bidirectional pedestrian flow model which involves the next-nearest-neighbor effect. The stability condition and the Korteweg-de Vries （KdV） equation are derived to describe the density wave of pedestrian congestion by linear stability and nonlinear analysis. Through theoretical analysis, the soliton solution is obtained.展开更多
Flow-based measurement is a popular method for various network monitoring usages.However, many flow exporting softwares have still low performance to collect all flows.In this paper, we propose a IPFIX-based flow expo...Flow-based measurement is a popular method for various network monitoring usages.However, many flow exporting softwares have still low performance to collect all flows.In this paper, we propose a IPFIX-based flow export engine with an enhanced and extensible data structure, called XFix, on the basis of a GPL tool,-nProbe.In the engine, we use an extensible two-dimensional hash table for flow aggregation, which is able to improve the performance of the metering process as well as support bidirectional flow.Experimental results have shown its efficiency in multi-thread processing activity.展开更多
The bottleneck effect on bidirectional crowd dynamics is of great theoretical and practical significance, especially for the designing of corridors in public places, such as subway stations or airports. Based on the f...The bottleneck effect on bidirectional crowd dynamics is of great theoretical and practical significance, especially for the designing of corridors in public places, such as subway stations or airports. Based on the famous social force model, this paper investigates the bottleneck effects on the free flow dynamics and breakdown phenomenon under different scenarios, in which different corridor shapes and inflow ratios are considered simultaneously. Numerical simulation finds an interesting self-organization phenomenon in the bidirectional flow, a typical characteristic of such a phenomenon is called lane formation, and the existence of which is independent of the corridor＇s shape and inflow rate. However, the pattern of the lane formed by pedestrian flow is related to the corridor＇s shape, and the free flow efficiency has close relationship with the inflow rate. Specifically, breakdown phenomenon occurs when inflows from both sides of the corridor are large enough, which mostly originates from the bottleneck and then gradually spreads to the other regions. Simulation results further indicate that the leaving efficiency becomes low as breakdown occurs, and the degree of congestion is proportional to the magnitude of inflow. The findings presented in this paper match well with some of our daily observations, hence it is possible to use them to provide us with theoretical suggestions in design of infrastructures.展开更多
基金Project supported jointly by the National Natural Science Foundation of China(Grant No.61233001)the Fundamental Research Funds for Central Universities of China(Grant No.2013JBZ007)
文摘Analysis of dynamic features of pedestrian flows is one of the most exciting topics in pedestrian dynamics. This paper focuses on the effect of homogeneity and heterogeneity in three parameters of the social force model, namely desired velocity, reaction time, and body size, on the moving dynamics of bidirectional pedestrian flows in the corridors. The speed and its deviation in free flows are investigated. Simulation results show that the homogeneous higher desired speed which is less than a critical threshold, shorter reaction time or smaller body size results in higher speed of flows. The free dynamics is more sensitive to the heterogeneity in desired speed than that in reaction time or in body size. In particular, an inner lane formation is observed in normal lanes. Furthermore, the breakdown probability and the start time of breakdown are focused on. This study reveals that the sizes of homogeneous desired speed, reaction time or body size play more important roles in affecting the breakdown than the heterogeneities in these three parameters do.
基金Project supported by the National Natural Science Foundation of China(Grant No.11072117)the Scientific Research Fund of Zhejiang Province,China(Grant No.LY13A010005)+4 种基金the Disciplinary Project of Ningbo City,China(Grant No.SZXL1067)the Scientific Research Fund of Education Department of Zhejiang Province,China(Grant No.Z201119278)the Natural Science Foundation of Ningbo City,China(Grant Nos.2012A610152 and 2012A610038)the K.C.Wong Magna Fund in Ningbo University,Chinathe Research Grant Council,Government of the Hong Kong Administrative Region,China(Grant No.CityU119011)
文摘This paper focuses on a two-dimensional bidirectional pedestrian flow model which involves the next-nearest-neighbor effect. The stability condition and the Korteweg-de Vries （KdV） equation are derived to describe the density wave of pedestrian congestion by linear stability and nonlinear analysis. Through theoretical analysis, the soliton solution is obtained.
文摘Flow-based measurement is a popular method for various network monitoring usages.However, many flow exporting softwares have still low performance to collect all flows.In this paper, we propose a IPFIX-based flow export engine with an enhanced and extensible data structure, called XFix, on the basis of a GPL tool,-nProbe.In the engine, we use an extensible two-dimensional hash table for flow aggregation, which is able to improve the performance of the metering process as well as support bidirectional flow.Experimental results have shown its efficiency in multi-thread processing activity.
基金Project supported jointly by the National Natural Science Foundation of China(Grant Nos.61322307 and 2016YJS023)
文摘The bottleneck effect on bidirectional crowd dynamics is of great theoretical and practical significance, especially for the designing of corridors in public places, such as subway stations or airports. Based on the famous social force model, this paper investigates the bottleneck effects on the free flow dynamics and breakdown phenomenon under different scenarios, in which different corridor shapes and inflow ratios are considered simultaneously. Numerical simulation finds an interesting self-organization phenomenon in the bidirectional flow, a typical characteristic of such a phenomenon is called lane formation, and the existence of which is independent of the corridor＇s shape and inflow rate. However, the pattern of the lane formed by pedestrian flow is related to the corridor＇s shape, and the free flow efficiency has close relationship with the inflow rate. Specifically, breakdown phenomenon occurs when inflows from both sides of the corridor are large enough, which mostly originates from the bottleneck and then gradually spreads to the other regions. Simulation results further indicate that the leaving efficiency becomes low as breakdown occurs, and the degree of congestion is proportional to the magnitude of inflow. The findings presented in this paper match well with some of our daily observations, hence it is possible to use them to provide us with theoretical suggestions in design of infrastructures.
