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Weihua Zhuang - One of the best experts on this subject based on the ideXlab platform.
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Microscopic Vehicle Mobility Model
Mobility Modeling for Vehicular Communication Networks, 2020Co-Authors: Khadige Abboud, Weihua ZhuangAbstract:Unlike traditional mobile ad hoc networks, the high node mobility in VANETs can cause frequent network topology changes and fragmentations. As discussed in Sect. 1.3, any change in network topology is directly or indirectly related to the change in Distance Headways among vehicles. This chapter presents a novel microscopic mobility model to facilitate VANET analysis. Firstly, A discrete-time finite-state Markov chain with state dependent transition probabilities is proposed to model the Distance Headway. The model captures the time variations of a Distance Headway and its dependency on Distance Headway value. Secondly, highway vehicular traffic is simulated using microscopic vehicle traffic simulator, VISSIM. Vehicle trajectory data collected from highways in the U.S. and that simulated by VISSIM are used to demonstrate the validity of the proposed mobility model for three vehicle density ranges. Finally, the proposed mobility model is extended to a group mobility model that describes the time variations of a system of Distance Headways between two non-consecutive vehicles. Using lumpability theory, a Markov chain with reduced state-space is proposed to represent the mobility of a group of vehicles.
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Stochastic Analysis of a Single-Hop Communication Link in Vehicular Ad Hoc Networks
IEEE Transactions on Intelligent Transportation Systems, 2014Co-Authors: Khadige Abboud, Weihua ZhuangAbstract:A vehicular ad hoc network (VANET) is a promising addition to our future intelligent transportation systems, which supports various safety and infotainment applications. The high node mobility and frequent topology changes in VANETs impose new challenges in maintaining a long-lasting connection between network nodes. As a result, the lifetime of communication links is a crucial issue in VANET development and operation. This paper presents a probabilistic analysis of the communication link in VANETs for three vehicle density ranges. First, we present the stationary distribution of the communication link length using mesoscopic mobility models. Second, we propose a stochastic microscopic mobility model that captures time variations of intervehicle Distances (Distance Headways). A discrete-time finite-state Markov chain with state-dependent transition probabilities is proposed to model the Distance Headway. Third, the proposed stochastic microscopic model and first passage time analysis are used to derive the probability distribution of the communication link lifetime. Numerical results are presented to evaluate the proposed model, which demonstrate a close agreement between analytical and simulation results.
I.a. Hansen - One of the best experts on this subject based on the ideXlab platform.
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Conflict Resolution and Train Speed Coordination Solving Real-Time Timetable Perturbations
IEEE Transactions on Intelligent Transportation Systems, 2007Co-Authors: Andrea D'ariano, Marco Pranzo, I.a. HansenAbstract:In this paper researchers present a method of rail traffic control and train scheduling to provide conflict resolution given a real-time timetable perturbation. Upon the determination of a conflict resolution for vehicle speed and coordination, the relevant data points such as the goal location, time, and speed could be relayed to conductors who could then adjust the speed accordingly. The model presented here also provides a determination of safe Distance Headway in addition to speed coordination issues with consecutive trains on the same track. Researchers applied their method computationally to existing rail networks between Leiden and Amsterdam in the Netherlands. They then considered 48 different test cases of potential perturbations in that network to test the efficacy of their system, particularly in the event of a highly disordered dispatching system. The researchers demonstrate the effectiveness of their variable-speed model as against a fixed-speed scheduling system.
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conflict resolution and train speed coordination for solving real time timetable perturbations
IEEE Transactions on Intelligent Transportation Systems, 2007Co-Authors: Andrea Dariano, Marco Pranzo, I.a. HansenAbstract:During rail operations, unforeseen events may cause timetable perturbations, which ask for the capability of traffic management systems to reschedule trains and to restore the timetable feasibility. Based on an accurate monitoring of train positions and speeds, potential conflicting routes can be predicted in advance and resolved in real time. The adjusted targets (location-time-speed) would be then communicated to the relevant trains by which drivers should be able to anticipate the changed traffic circumstances and adjust the train's speed accordingly. We adopt a detailed alternative graph model for the train dispatching problem. Conflicts between different trains are effectively detected and solved. Adopting the blocking time model, we ascertain whether a safe Distance Headway between trains is respected, and we also consider speed coordination issues among consecutive trains. An iterative rescheduling procedure provides an acceptable speed profile for each train over the intended time horizon. After a finite number of iterations, the final solution is a conflict-free schedule that respects the signaling and safety constraints. A computational study based on a hourly cyclical timetable of the Schiphol railway network has been carried out. Our automated dispatching system provides better solutions in terms of delay minimization when compared to dispatching rules that can be adopted by a human traffic controller
Wei Guo Song - One of the best experts on this subject based on the ideXlab platform.
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Quantifying the impact of luggage on pedestrian walking and running movements
Safety Science, 2020Co-Authors: Jun Zhang, Wei Guo SongAbstract:Abstract Knowledge on the movement of luggage-laden pedestrians is important to improve the safety level in transport hubs especially in emergencies. In this study, a controlled directional flow experiment under a 50–50% composition of pedestrians, with and without luggage was carried out in a straight corridor. Six different arrangements of the luggage in the crowd were considered under both walking and running conditions. It was found that the boundary Distances between a pedestrian and the left-side and right-side wall show obvious differences due to pedestrians' preferences of carrying the luggage with their right hand. The luggage-laden pedestrians influence the interpersonal Distance of their right neighbors more than the left ones. Besides, the existence of luggage would increase the Distance Headway between two neighbor luggage-laden pedestrians and also between two neighbor non-luggage pedestrians. Individual speeds were also analyzed by considering different types of pedestrians in the proximity of the individual. It was observed that luggage does not necessarily reduce pedestrian speed.
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Single-file Movement of Ants Stressed by a High Temperature
Collective Dynamics, 2020Co-Authors: Qiao Wang, Wei Guo Song, Shujie Wang, Siuming LoAbstract:Single-file movement is a universal pattern in both nature and human society. In this paper, we investigate single-file movement of ants (Camponotus japonicus) driven by a high temperature in a narrow channel. Here, ants were placed in a chamber. The chamber was connected to a narrow channel which was 10 cm long and 0.6 cm wide so that the ants can escape through it one by one. Both chamber and narrow channel were in high temperature environment. In the channel, the random pause was observed due to the characteristic of ants. Moreover, ants were inclined to following the preceding one and trying to overtake it, which is different from the movement in natural investigation. On the other hand, the speed increased with Distance Headway when the Distance Headway is less than 0.26 cm, that is less than the body size of an ant. Furthermore, touching phenomenon was observed. When the following ants touched the preceding one, they could reduce speed, stop or move backward. On the contrary, the preceding ants increased their speed. Thus, the touching effect in multiple ants experiment can enhance the evacuation efficiency.
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Experimental Study on Single-File Movement with Different Stop Distances
The Proceedings of 11th Asia-Oceania Symposium on Fire Science and Technology, 2019Co-Authors: Qiao Wang, Wei Guo Song, Jun Zhang, Liping Lian, Siuming LoAbstract:The single-file movement formed at exit, passageway, and stairway is a common and fundamental phenomenon in building evacuation when fire happened. In order to investigate single-file movement, the controlled experiments contained three parts: acceleration, steady state, and deceleration are effective research methods. In this paper, we conducted single-file movement experiments with two different commands in decelerating phase: (1) normal stop, (2) close stop, i.e., stop at the place as close as possible to the predecessor, in which participants move at different free moving speed. Through rescaling the speed, there is no influence for different free moving speed on speed–Distance Headway relationship. The linear fitting curve is executed to obtain a quantitative description of the speed–Distance Headway relation, and the slope in the close stop experiment is larger than that in the normal stop. It is found that there is a little difference in the decelerating phase for different participants and the average close stop Distance is 0.34 m, which is a little bigger than average chest width 0.3 m. For the normal stop, the comfortable stop Distance is dependent on individual proxemics. In the relation of speed–time, it was divided into two stages, which is fitted using linear regression. The value of negative acceleration in stage I is greater than stage II. Similar to the fitting result of speed–Distance Headway, participants in close stop experiments have bigger negative acceleration in stage I. However, in stage II, due to the uncertainty of close stop Distance for different participants, the value of negative acceleration in close stop is smaller. Actually, in normal conditions, participants stopped with their comfortable stop Distance when the predecessor stopped. However, in emergency or hurried conditions, the stop Distance would be smaller. Therefore, it is useful to investigate the movement behavior in an emergency (such as fire and earthquake) and hurried conditions when the predecessor stopped suddenly.
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Experimental study on the single-file movement of mice
Physica A-statistical Mechanics and Its Applications, 2019Co-Authors: Hanyi Xiao, Qiao Wang, Jun Zhang, Wei Guo SongAbstract:Abstract Exploring mice movement characteristics is a basic issue of using mice to study crowd behavior in evacuation due to cost and ethical consideration of pedestrian evacuation experiments. In this paper, single-file experiment was performed in a 2m-long passageway with trained mice. Mice movement characteristics were studied by fundamental diagrams in macroscopic view and the velocity–Distance Headway relation in microscopic analysis. The results show the decaying velocity with density at low densities, and show the non-strict relation of velocity and density at high densities. From microscopic perspective, random pause was observed, and mice can move forward together when overlap occurs. Further, the numerical simulation validates the scattered effect of the random pauses on the velocity–Distance Headway diagram, and indicates that mice velocity increase with Distance Headway sharply and then keeps stable. This study provides insights into mice movement as well as the similarities and differences between mice and humans in movement, and it may contribute to crowd evacuation studies.
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Experiment and Modeling of Microscopic Movement Characteristic of Pedestrians
Procedia Engineering, 2013Co-Authors: Wei Guo Song, Wei Lv, Zhi Ming FangAbstract:Abstract Evacuation models considering microscopic movement characteristics are efficient and helpful for designing safe evacuation facilities, while crucial parameters adopted in the models are important and valuable for calibrating or improving the evacuation models. In this paper, the method and technology for executing and analyzing two crucial controlled experiments, single-file experiment and bottleneck experiment, are reviewed in detail. Based on the observation and some typical characteristics of the single-file experiment, a one dimensional continuous Distance model (CDM) was proposed in our previous work and in this study it is improved by introducing the desired walking direction so as to describe the two-dimensional bottleneck movement. Experiment results such as velocity, lateral sway, step frequency vs. Distance Headway, velocity vs. Distance Headway, flow, and lane formation are analyzed. In particular, the mode of lane formation is discussed and the critical widths for lane formation are obtained. Comparison between simulation and experiment shows the CDM and its improved version can describe the pedestrian movement very well.
Khadige Abboud - One of the best experts on this subject based on the ideXlab platform.
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Microscopic Vehicle Mobility Model
Mobility Modeling for Vehicular Communication Networks, 2020Co-Authors: Khadige Abboud, Weihua ZhuangAbstract:Unlike traditional mobile ad hoc networks, the high node mobility in VANETs can cause frequent network topology changes and fragmentations. As discussed in Sect. 1.3, any change in network topology is directly or indirectly related to the change in Distance Headways among vehicles. This chapter presents a novel microscopic mobility model to facilitate VANET analysis. Firstly, A discrete-time finite-state Markov chain with state dependent transition probabilities is proposed to model the Distance Headway. The model captures the time variations of a Distance Headway and its dependency on Distance Headway value. Secondly, highway vehicular traffic is simulated using microscopic vehicle traffic simulator, VISSIM. Vehicle trajectory data collected from highways in the U.S. and that simulated by VISSIM are used to demonstrate the validity of the proposed mobility model for three vehicle density ranges. Finally, the proposed mobility model is extended to a group mobility model that describes the time variations of a system of Distance Headways between two non-consecutive vehicles. Using lumpability theory, a Markov chain with reduced state-space is proposed to represent the mobility of a group of vehicles.
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Stochastic Analysis of a Single-Hop Communication Link in Vehicular Ad Hoc Networks
IEEE Transactions on Intelligent Transportation Systems, 2014Co-Authors: Khadige Abboud, Weihua ZhuangAbstract:A vehicular ad hoc network (VANET) is a promising addition to our future intelligent transportation systems, which supports various safety and infotainment applications. The high node mobility and frequent topology changes in VANETs impose new challenges in maintaining a long-lasting connection between network nodes. As a result, the lifetime of communication links is a crucial issue in VANET development and operation. This paper presents a probabilistic analysis of the communication link in VANETs for three vehicle density ranges. First, we present the stationary distribution of the communication link length using mesoscopic mobility models. Second, we propose a stochastic microscopic mobility model that captures time variations of intervehicle Distances (Distance Headways). A discrete-time finite-state Markov chain with state-dependent transition probabilities is proposed to model the Distance Headway. Third, the proposed stochastic microscopic model and first passage time analysis are used to derive the probability distribution of the communication link lifetime. Numerical results are presented to evaluate the proposed model, which demonstrate a close agreement between analytical and simulation results.
Serge P. Hoogendoorn - One of the best experts on this subject based on the ideXlab platform.
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Adaptations in driver behaviour characteristics during control transitions from full-range Adaptive Cruise Control to manual driving: an on-road study
Transportmetrica, 2020Co-Authors: S.f. Varotto, Haneen Farah, Klaus Bogenberger, B. Van Arem, Serge P. HoogendoornAbstract:Adaptive Cruise Control (ACC) can reduce traffic congestion and accidents. In dense traffic flow conditions and when changing lanes, drivers prefer to deactivate the ACC. These control transitions between automation and manual driving could impact driver behaviour characteristics. However, few studies have analysed the magnitude and duration of these adaptations. This research aims at quantifying the adaptations in speed, acceleration, Distance Headway and relative speed when drivers resume manual control. We collected driver behaviour data in an on-road experiment with full-range ACC during peak hours in Munich. We analysed these data using linear mixed-effects models to identify statistically significant changes in driver behaviour characteristics after drivers resumed manual control (transition period). The results reveal that the speed decreased significantly after the system was deactivated and it increased significantly after the system was overruled by pressing the gas pedal. These adaptations might have a substantial impact on traffic efficiency and safety.
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Operational Walking Dynamics of Crowds Modeled with Linear Regression
Transportation Research Record, 2017Co-Authors: Dorine C Duives, Winnie Daamen, Serge P. HoogendoornAbstract:In this study the influence of interaction characteristics on operational walking dynamics within a crowd—specifically the influence of the Distance Headway, time Headway, angle of sight, angle of interaction, walking speed, and number of pedestrians located nearby on a pedestrian’s change in speed and direction—is investigated. To the authors’ best knowledge, this is the first time that the combined effect of the characteristics of interactions between pedestrians on the operational walking dynamics of pedestrians has been quantified. The walking speed and the number of pedestrians in close proximity were found to influence the adaptation of speed and direction. The other characteristics of the interaction affect either the change in speed (i.e., Distance Headway and interaction angle) or the change in direction (i.e., time Headway and angle of sight). The results of this study strongly indicate that the density experienced by pedestrians is not the only characteristic of the crowd that affects pedestria...
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The influence of the interaction characteristics on the movement dynamics of pedestrians
2016Co-Authors: Dorine C Duives, Winnie Daamen, Serge P. HoogendoornAbstract:One of the fundamental properties of pedestrian simulation models is their capability to predict the future movement dynamics of pedestrians depending on the current state of the pedestrian traffic flow, more specically the walking behaviour of neighbouring pedestrians. This paper investigates the influence of the interaction characteristics on the strength of the reaction of pedestrians walking within a crowd, where the reaction consists of the absolute change in walking direction and speed. This paper studies the influence of the Distance Headway, time Headway, angle of sight, angle of interaction, absolute speed and the number of pedestrians located nearby has been studied. Based on these ndings two main conclusions can be drawn, being 1) the operational adaptations of the walking behaviour of pedestrians is influenced by more characteristics of the situation than just the Distance Headway with respect to the pedestrian walking directly in front of a pedestrian, 2) pedestrians are more likely to change their direction rather than their walking speed when other pedestrians are located within close proximity.
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influence of group size and group composition on the adhered Distance Headway
Transportation research procedia, 2014Co-Authors: Dorine C Duives, Winnie Daamen, Serge P. HoogendoornAbstract:Research into the influence of groups on pedestrian flow dynamics has been limited. Previous research found that group size influences the walking velocity of pedestrians within the group and as such the capacity the pedestrian infrastructure. This paper's aim is to provide quantitative insights into the influence of group size and composition of demographic characteristics on the Distance Headway pedestrians adhere to with respect to respectively other groups and other individuals within their own group, during bi-directional crowd movements. It is concluded that the composition of age and genders within a group, as well as the total size of the group influences also the Distance Headway pedestrians adhere during large crowd movements. As such, the presence of groups changes the dynamics of the crowd movements. This can result in a decrease of the capacity of the infrastructure.
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Heterogeneity in car-following behavior: Theory and empirics
Transportation Research Part C: Emerging Technologies, 2011Co-Authors: Saskia Ossen, Serge P. HoogendoornAbstract:The aim of this paper is to gain insights into the level of heterogeneity in car-following behavior in real traffic. We use a large sample of trajectory observations collected by means of a helicopter to identify differences between the car-following behaviors of: (1) passenger car drivers, (2) passenger car drivers and truck drivers and (3) passenger car drivers following a passenger car and passenger car drivers following a truck. We thereto calibrate eight car-following models making different assumptions about the way in which drivers follow their leader(s) on the same lane. We show that considerable behavioral differences exist between passenger car drivers. Different passenger car drivers do not only consider different stimuli (like speed difference(s) with the leading car(s) and Distance Headway(s) to leading car(s)) but also the extents to which these stimuli influence their behavior differ. Truck drivers turn furthermore out to adopt in general a more robust car-following behavior than passenger car drivers. Their speeds show, for example, less variation over time. We also find indications that the desired Headways of passenger car drivers are lower when following a truck than when following a passenger car. ?? 2010.