Routing algorithm of real-time multicast communication based on Hadoop platform

2021 ◽  
Author(s):  
Zhengnan Wu
Author(s):  
Wanli Zhang ◽  
Xiaoying Yang ◽  
Qixiang Song ◽  
Liang Zhao

To ensure the transmission quality of real-time communications on the road, the research of routing protocol is crucial to improve effectiveness of data transmission in Vehicular Ad Hoc Networks (VANETs). The existing work Q-Learning based routing algorithm, QLAODV, is studied and its problems, including slow convergence speed and low accuracy, are found. Hence, we propose a new routing algorithm FLHQRP by considering the characteristics of real-time communication in VANETs in the paper. The virtual grid is introduced to divide the vehicle network into clusters. The node’s centrality and mobility, and bandwidth efficiency are processed by the Fuzzy Logic system to select the most suitable cluster head (CH) with the stable communication links in the cluster. A new heuristic function is also proposed in FLHQRP algorithm. It takes cluster as the environment state of heuristic Q-learning, by considering the delay to guide the forwarding process of the CH. This can speed up the learning convergence, and reduce the impact of node density on the convergence speed and accuracy of Q-learning. The problem of QLAODV is solved in the proposed algorithm since the experimental results show that FLHQRP has many advantages on delivery rate, end-to-end delay, and average hops in different network scenarios.


Author(s):  
Jooyoung Kim

Demand responsive transport (DRT) is operated according to flexible routes, dispatch intervals, and dynamic demand, is attracting a lot of attention. The biggest characteristic of DRT service is that the vehicle routes and schedules are operated optimally based on real-time travel requests of using passengers without fixed operating schedules. Today, the smart-city era has arrived, particularly because of progress in the wireless communications technology and technology related to location information service and real-time passenger demands and requests, and services that change the vehicles’ operating schedules in real-time according to dynamic demand have attracted more attention. In this study, we analyze the effects of the DRT system to solve the first mile/last mile problem based on a proposed DRT routing algorithm considering real-time travel behavior. The algorithm is modified from the dynamic vehicle routing problem (DVRP), in which a DRT-based routing algorithm tends to minimize users’ cost and providers’ operation cost. So far, the DVRP has only been able to serve a single request per vehicle at a time. However, this needs to be extended for the purpose of DRT, wherein several passengers board a vehicle at the same time. The routing algorithm can serve multiple requests at a time and schedule picks ups, drop offs, and rides according to the requests and as calculated by the dispatch algorithm. The basic principle of routing is as follows. The DRT vehicle moves on an attractive path and picks up a passenger if boarding is requested, but it does not simply hang around as a DVRP would. In this step, if another DRT vehicle is present near another passenger, the vehicle that would minimize that passenger’s total travel time picks up the passenger. The optimal routing algorithm developed in this study is applied to the activity-based model; that is, a microscopic traffic demand estimation method is implemented through an activity-based model by using an open-source, activity-based model package called Multi-Agent Transport Simulation (MATSim). MATSim is used for the simulation, because it combines a multi-modal traffic flow simulation with a scoring model for agents, and it provides co-evolutionary algorithms that can alter agents’ daily routines. This process is applied to a type of mode choice and route choice repeatedly over several iterations until some form of user equilibrium has been reached. This study analyzed the feasibility of implementing the DRT service by analyzing the benefits for the users and cost of the operator from the effects of increasing public transportation use and providing personalized mobility service based on DRT implementation by the introduction of DRT will be analyzed according to the scale of DRT supply. Through the simulation, the DRT is expected to provide convenient, fast, and cost-effective mobility services to customers; provide an optimal vehicle scale to providers; and, ultimately, achieve a safe and efficient transportation system.


2019 ◽  
Vol 33 (16) ◽  
pp. 1950169 ◽  
Author(s):  
Luo Kaitian ◽  
Liu Gang

The real throughput of a network is dependent on the adopted routing algorithm. In this study, we further analyze the influence of real-time traffic condition and travel distance on network throughput in a dynamic transportation environment, and define a mathematical model to describe the routing cost for a packet spending to travel along a path with considering real-time traffic condition and travel distance. Based on the model, this paper proposes a routing strategy by imposing the minimum cost. Experimental results show that the proposed routing strategy is efficient in improving network throughput and balancing traffic load.


2018 ◽  
Vol 14 (10) ◽  
pp. 155014771880568 ◽  
Author(s):  
Wu Jiawei ◽  
Qiao Xiuquan ◽  
Nan Guoshun

Recently, there has been a surge of the video services over the Internet. However, service providers still have difficulties in providing high-quality video streaming due to the problem of scheduling efficiency and the wide fluctuations of end-to-end delays in the existing multi-path algorithms. To solve these two problems affecting video transmission quality, networks are expected to have the capability of dynamically managing the network nodes for satisfying quality-of-service requirements, which is a challenging issue for media streaming applications. Against this changing network landscape, this article proposes a dynamic and adaptive multi-path routing algorithm under three constraints (packet loss, time delay, and bandwidth) that are based on software-defined network for centralized routing computations and real-time network state updating in multimedia applications. Compared with related multi-path routing proposals, dynamic and adaptive multi-path routing makes efficient use of the latest global network state information achieved by the OpenFlow controller and calculates the optimal routes dynamically according to the real-time status information of the link. Moreover, our proposed algorithm can significantly reduce the computational overhead of the controller while completing a fine-grained flow balance. Experimental results show that dynamic and adaptive multi-path routing significantly outperforms other existing scheduling approaches in achieving a 35%–70% improvement in quality-of-service.


2012 ◽  
Vol 30 (1) ◽  
pp. 41-46
Author(s):  
Roman Messmer ◽  
Jörg Keller

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