Abstract. Aiming at the complicated environment of Vehicular Ad Hoc Networks(VANET),in this paper,a region-based adaptive clustering algorithm (ZACA) is proposed.Through classifying the road environment into segment and intersection, respectively calculating the connectivity according to the different road environments, and combine it with the regional location and the traditional synthesis weights of the Weighted Clustering Algorithm,the election of the cluster head under different road models and the maintenance of cluster based on the network area are realized.Simulation result shows this method can adapt to vehicular network environment effectively, and also can improve the stability of the cluster and reduce the clustering overhead.

Abstract. At present, domestic and international research on the video transmission mainly concentrated in video coding, multipath transmission, multicast transmission. The transmission and QoS security technology will be studied to against the characteristics of video transmission and wireless ad hoc network.How to transfer more video streaming under conditions of the limited network resource is a meaningful topic.In this paper,the conception of user level into service classification is introduced and a framework named UVQM is proposed.The UVQM can provide QoS security for video transmission and ensure more streaming transmitted without congestion.