Dynamic network topology is one of the important characteristics of vehicle Ad Hoc networks (VANET). Based on Intelligent Driver Model with Lane Changes (IDM-LC), the VanetMobiSim was used to study the dynamic centrality of topology for VANET in detail. The temporal network model of VANET was built. The evaluation method of dynamic centrality based on the attenuation factor and information store-and-forward index was established, which not only can describe the relation between the current network topology and the historical one, but also can depict the store-and-forward mechanism of information transmission in VANET. Finally, the dynamic centrality of VANET was analyzed through the simulation experiment. The results show that although the dynamic centrality of VANET topology varies with time and parameters, the ranking of important nodes remains relatively stable. This conclusion not only can help us identify the relay nodes of information transmission better to achieve the successful delivery of information, but also provides guidance for invulnerability of VANET topology.

Concerning the problem of invulnerability in Vehicular Ad Hoc NETwork (VANET), the invulnerability characteristics for VANET under random attacks and intentional attacks were analyzed. Firstly, the largest connected component, average size of components, critical point removal ratio as well as network efficiency were proposed to be used for the invulnerability evaluation metrics for VANET. Then, based on intelligent driver model with lane changes, the VANET was established through VanetMobisim software. Finally, the influence of the number of nodes, transmission ranges and patterns of attack on VANET invulnerability were given. The experimental results show that the VANET has a strong invulnerability faced with random attacks while its invulnerability to intentional attacks is fairly low as a result of the uneven degree distribution of vehicles; the intentional attacks based on node betweenness destroy the networks more quickly and strongly. The derived rules can provide the optimization of VANET topology control, protocol development and network management with new guidance.

Aiming at the problem of connectivity in Vehicular Ad Hoc Network (VANET), the evolution characteristics of connectivity characteristics for VANET were analyzed. Firstly, the number of connected components, connectivity probability and connectivity length were proposed to be used for the evaluation connectivity metrics for VANET. Then, based on Intelligent Driver Model with Lane Changes (IDM-LC), the VANET was set up through VanetMobiSim software. Finally, the relation of node communication radius and the average number of connected components, average connectivity probability and average connectivity length were given. At the same time, the statistical distribution of the number of connected components was also analyzed. The results show that number of connected components follows a normal distribution by using Q-Q plot and T-test. Moreover, the results also show that the statistical distribution of the number of connected components is independent of the node communication radius.