Papers by Keyword: Average Delay

Abstract: As an important index on evaluating intersection traffic efficiency, vehicle average delay played more and more roles on traffic prediction and evaluation modeling, this paper proposed an intersection signal warrant model using average delay which can evaluate traffic efficiency. According to compare the average delay of intersections before and after installing signal, average delay critical match model is established to show the warrant of signal setting. In this model, traffic volumes of major and minor approaches are main variables which are to argue whether the intersections need to be signalized, and several kinds of critical volume curves diagrams are given to show the warrant of different characteristics’ intersections.

Abstract: To make full use of green time of each phase to alleviate congestion in urban isolated intersections, an optimization algorithm of real-timing signal control is proposed. By monitoring traffic flow at the isolated intersection, the average utilization rate of green time of each phase is calculated. The green time of each phase is then adjusted automatically to maintain a balanced green time utilization rate with the presented optimization algorithm. Simulation results indicate that the average delay and the queue length of the presented algorithm are less than the fixed-time signal plan at peak times, and the efficiency of the intersection traffic is improved.

Abstract: The objective of this paper is to investigate genetic algorithms (GA) on traffic signal timing at a congested isolated intersection. The objective function for GA modeling was established on the strategy of minimizing average delay and GA was applied to search for the optimal signal timing. Then microsimulation is used to compare the optimized timings produced by the GA with those obtained for the same intersection using Synchro. Results indicated that applying GA results in lower values of average delay and average number of stops in congested condition than applying Synchro.

Abstract: The left-turning traffic forbiddance measure is an important mode of traffic organization of intersection, but the traffic management departments are puzzled by the implementation condition, implementation method and efficiency evaluation. The traffic impact analysis of left-turning traffic flows and the advantages of left-turning traffic forbiddance measure is analyzed in paper, then the implementation flows is summarized. The implementation condition and method are determined, and the average delay of intersections in the whole region are chosen as the evaluation index of operation efficiency of the left-turning traffic forbiddance measure. So the calculation method of efficiency between pre and post adopted the left-turning traffic forbiddance measure is proposed. The intersections of business district in City Hengyang is chosen as example for verifying the implementation method of left-turning traffic forbiddance, and the efficiency between pre and post adopted the left-turning traffic forbiddance measure is comparatively analyzed and the VISSIM simulation software is applied for verifying the effect of the left-turning traffic forbiddance measure.

Abstract: In order to analyze and evaluate real-time performance of CAN network, the OPNET models of CAN network with Fixed Priority Scheduling (FPS) and Earliest Deadline First (EDF) have been set up in this paper. Based on simulation experiments, the performances of average delay and transmission success ratio in the two models are analyzed and the experiments also indicate that under normal load condition the two scheduling algorithm both can send data frame successfully before the deadline. In a slight overload condition FPS algorithm makes the transmission delay of low priority data frame significantly increased, and even occurs the phenomenon that low priority data frame can not be sent at all times; while the EDF algorithm can make all the nodes to complete the data frames in less than 3ms transmission delay, it meets the delay requirements that are delay should less than 10ms in most control systems, it indicates that EDF algorithm has the better scheduling and availability in soft real-time system.

Abstract: In order to analyze and evaluate real-time performance of CAN bus with priority promotion algorithm (PPA), the OPNET model of CAN bus with PPA has been set up in this paper. Based on simulation experiments, the performances of average delay of PPA and Fixed Priority Scheduling (FPS) and Earliest Deadline First (EDF) algorithm are analyzed and the experiments also indicate that in a slight overload condition FPS algorithm makes the transmission delay of low priority data frame increased significantly, and even occurs the phenomenon that low priority data frame can not be sent at any times; EDF algorithm keeps the average delay of all the node at 2ms or so, the objective of scheduling information is achieved, but the average delay of hard real-time node is increased; compared to EDF algorithm, PPA increases the average delay of non real-time node appropriately through using different promotion weights, and reduces the average delay of hard real-time node. The results show that the PPA has the better scheduling and availability in real-time control system.

Abstract: DATA flooding attack is a serious menace for the security of on-demand routing protocol in Ad Hoc networks. In the paper, on the basis of three typical on-demand routing protocols AODV, DSR and TORA, we present a special security scheme against data flooding attack. Then we simulate the scheme on NS2 platform and compare two performance parameters before and after using the scheme: average delay and packet delivery rate. The results indicate that this project is comparatively effective to resist the DATA flooding attack.