Metaheuristics for . . . P2P Information in VANETs

Journal of Southwest Jiaotong University, 2019

Vehicular Ad Hoc network (VANET) becomes an important technology. Specially, it assists vehicle to vehicle communication. Enhancing and finding a modified protocol of routing for this type of networks is a clear difficulty because these are self-managed, distributed, and large networks. This paper specifies this difficulty by discussing VANET challenges to find the accurate VANET algorithms which work locally but effect the entire network performance generally. All the more particularly, we used various snapshots at previews from urban motorways and intercity highways of various sizes and densities, and studied different variables, for example, the grouping coefficient , the hub degree dissemination, and the normal most brief way length, keeping in mind the end goal to better comprehend the system structure and contrast it with structures regularly found in extensive genuine systems, for example, little world and sans scale systems. This paper utilized this information to enhance th...

Revista Facultad De Ingenieria Universidad De Antioquia, 2013

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The use of real-time information in Intelligent Transportation Systems (ITS) in particular Vehicular Ad hoc Networks (VANETs) has the potential to improve traffic conditions and reduce travel delays by facilitating better utilization of available capacity. These systems exploit currently available and emerging computer, communication, and control technologies to monitor, manage, and control the transportation system. They also provide various levels of traffic information and trip advisory service to system users, service providers, so that travellers or drivers can make timely and informed travel decisions. The success of ITS technology deployments is heavily dependent on the availability of timely and accurate estimates of prevailing and emerging traffic conditions. As such, there is a strong need for a "traffic prediction system". The needed system is to utilize advanced traffic models to analyze data, especially real-time traffic data, from different sources to estimate and predict traffic conditions so that proactive strategies can be implemented to meet various traffic control, management, and operation objectives. Vehicular Ad hoc Networks are an envision of the Intelligent Transportation Systems. Vehicles communicate with each other via Inter-Vehicle Communication (IVC) as well as with roadside base stations via Roadside-to-Vehicle Communication (RVC). The optimal goal is that vehicular networks will contribute to safer and more efficient roads in the future by providing timely information to drivers and concerned authorities. The aim of this research was to develop an embedded system that would utilize the real-time information found in Intelligent Transportation Systems through the use of VANETs. This system was simulated using the C++ language and a combinatorial optimization algorithm was used to find cost effective routes from source to destination that would be able to meet the fuel or time constraints. By using these system drivers and other users would be able to make informed decisions to choose the feasible route based on the fuel or time required around the path/road from its current position to destination. The proposed embedded system is simple and can easily be developed and adapted to run in any environment that uses VANETs. This research provided the foundation of developing a future embedded system that can be used in Vehicular Ad Hoc Networks for real road traffic situations.

Simulation today is one of the most used tools in science and engineering. Traffic engineering is no exception. Simulators to be usable passes through processes of verification, validation and calibration. All simulators are based on assumptions and parameters that need to be calibrated so as to be practical in real world applications. Some parameters change from site to site. Therefore, the calibration process is often needed. Calibration can be seen as an optimization process that seeks to minimize the difference between observed and simulated measures. The question of which optimization technique suits more for this particular problem remains open. In this paper the convergence velocity of main heuristic optimization techniques, namely Genetic Algorithm (GA), Tabu Search (TS), Particle Swarm Optimization (PS) and Simultaneous Perturbation for Stochastic Approximation algorithm (SPSA) were used to calibrate a traffic simulation model called SUMO. The results of the calibration of the mentioned optimization techniques were compared. Classical optimization techniques, namely Neldear-Mead and COBYLA were used as a baseline comparison. Each technique has its own parameters that affect convergence velocity. Therefore, optimization techniques themselves need to be calibrated. However, TS and PS are not widely used to calibrate traffic simulators. They perform well in this particular problem. PS is highly parallel compared to the TS and SPSA. The paper shows that classical optimization techniques are not suitable for this particular problem, PS and TS appear to be better than GA and SPSA. PS seems to be a promising optimization technique.

In this paper we present a new dynamic road traffic routing algorithm, for enhanced clearing out of traffic from congested areas of the traffic network. The main objective of designing this algorithm is to implement a system that optimizes the rate of flow of traffic throughout the road network by minimizing traffic congestion rates. By crosscorrelation analysis the system analyzes the relation between lanes, in particular the rate of flow of traffic between lanes. It is used to compute the Time Difference of Arrival (TDOA), which in this context estimates the amount of time a fleet of traffic takes to travel from one intersection to the next. These time estimates are then used together with traffic counts at each intersection, and traffic weights which depict traffic flow patterns between lanes, to compute link scores and path scores for each road link and path, respectively. These scores are then presented as a network model based on the concerned road part of the road network. After all this, the algorithm uses this network model to compute an optimized sequential opening of the traffic lights in within that particular area. This algorithm is a dynamic model that mimics the operation of a police officer who controls traffic flow at road intersections during bad traffic congestion, the practice which is common here in Botswana and other third world countries.

IEEE Intelligent Transportation Systems Magazine

Vehicular Ad Hoc networks (VANET) becomes an important technology. Specially, it assists vehicle to vehicle communication. Enhancing and finding a modified protocol of routing for this type of networks is a clear difficulty because these are self-managed, distributed, and large networks. This paper specifies this difficulty by discussing VANET challenges to find the accurate VANET algorithms which work locally but effect the entire network performance generally. All the more particularly, we used various snapshots at previews from urban motorways and intercity highways of various sizes and densities, and studied different variables, for example, the grouping coefficient , the hub degree dissemination, and the normal most brief way length, keeping in mind the end goal to comprehend the system structure and contrast it with others regularly got in extensive genuine systems, for example, little world and sans scale systems. This paper utilized this data for develop VANET conventions. As an illustrative case, it exhibited that, by including segments which utilize this data, the overhead of the traditional urban highway can be diminished liberally with no imperative execution degradation. The results of the proposed algorithm convention can essentially lessen the system overhead without corrupting the reachability execution particularly in medium and high system thickness situations. Moreover, it stills an intriguing subject for future examination to assess the effect of components.

2012

The most important component of a vehicular ad hoc network (VANET), besides VANET-enabled vehicles, is roadside units (RSUs). The effectiveness of a VANET largely depends on the density and location of these RSUs. During the initial stages of VANET, it will not be possible to deploy a large number of RSUs either due to the low market penetration of VANET-enabled vehicles or due to the deployment cost of RSUs. There is, therefore, a need to optimally place a limited number of RSUs in a given region in order to achieve maximum performance. In this paper, we present two different optimization methods for placement of a limited number of RSUs in an urban region: an analytical Binary Integer Programming (BIP) method and a novel Balloon Expansion Heuristic (BEH) method. BIP method utilizes branch and bound approach to find an optimal analytical solution whereas BEH method uses balloon expansion analogy to find an optimal or near optimal solution. Our evaluations show that both methods perform optimally or near optimally compared with the exhaustive method. Further, BEH method is more versatile and performs better than BIP method in terms of computational cost and scalability.

Combinatorial Optimization, 2007

2009

This paper deals with nonlinear optimization of a stochastic system via simulation and a heuristic algorithm. These tools are used for optimization of the time parameters of the traffic lights of three junctions at Konečného square in Brno, Czech Republic, in order to reach maximum possible throughput. The objective is to minimize average waiting time in the system that might be described as an open queuing network. This is done in two steps: building a simulation model of Konečného square in Java using SSJ (Stochastic Simulation in Java a Java library for stochastic simulation) and implementing a heuristic algorithm Simulated Annealing that is using the simulation model for optimization. After a brief description of the traffic system, its mathematical and simulation models are introduced. Then the way of getting input data is discussed as well as verification and validation of the simulation model. The results of an optimization based on Simulated Annealing are shown and interpret...