Mission-critical military operations with dismounted soldiers are frequently characterized by high battlefield dynamics. In such scenarios a mobility model can manage soldiers' movements dynamically especially under enemy attacks. This paper presents a Group Mobility Model simulating realistic soldier and leader battlefield behaviors. Our model analyzes communication between a group of dismounted soldiers deployed in a mobile ad hoc network (MANET) and their leader under several perturbation factors (e.g., noise and enemies attacks) which affect movements and topology connectivity. Results show that the dismounted soldiers' collective movement improves the capacity of communication channels, whereas noise uncertainty may dramatically destroy the network. Moreover, the enemy's presence, another disorder parameter, changes qualitatively and quantitatively the army's wireless communication topology. Enemy numbers decrease almost linearly the throughput at the sink node (commander). A discussion of results follows, using distributions of path lifetimes, path lengths, packet delivery and group sizes in the communication soldiers' network.

Urban transportation with multiple roundabouts is facing significant challenges such as traffic congestion, gridlock and traffic accidents. In order to understand these behaviors, we propose a two-dimensional cellular automata (CA) model, where all streets are two-way, with one lane in each direction. To allow the turning movement, a roundabout is designed for each intersection where four roads meet. The distance between each pair of roundabouts is configured with the parameter K while the turning behavior of drivers is modeled by a parameter γ. To study the impact of these different parameters on the urban traffic, several traffic metrics are considered such as traffic flow, average velocity, accident probability and waiting time at the entrance of roundabout. Our simulation results show that the urban traffic is in free flow state when the vehicle's density is low enough. However, when the density exceeds a critical density ρ c , the urban traffic will be in gridlock state whenever γ is nonzero. In the case where γ = 0, the urban traffic presents a phase transition between free flow and congested state. Furthermore, detailed analysis of the traffic metrics shows that the model parameters (γ, K) have a significant effects on urban traffic dynamics.

Recently, localization accuracy of unknown nodes has become a critical and challenging issue for many Wireless Sensor Networks (WSNs) and Internet of Things (IoT) applications. Without associating the detected event with its precise geographic location will be surely considered meaningless for these applications. Among all localization algorithms, we observe that the DV-Hop localization algorithm is highly recommended to use in many fields of application due to its simplicity, feasibility, low cost, and no extra hardware requirements, but the localization error caused by the DV-Hop algorithm is relatively large. In this current work, based on both the DV-Hop algorithm and the Particle Swarm Optimization algorithm, we proposed four new localization algorithms to overcome the shortcomings of low accuracy that the basic DV-Hop based algorithms produce. The simulation results showed that the proposed localization algorithms can achieve a better localization performance in terms of accuracy in comparison with other existing algorithms such as basic DV-Hop, MDV-Hop and DV-HopPSO under different random network topologies. We also observed that a significant localization accuracy is achieved by the proposed algorithm HWDV-HopPSO.

In the future battlefields, communication between commanders and soldiers will be a decisive factor to complete an assigned mission. In such military tactical scenarios, network topology is constrained by the dynamics of dismounted soldiers in the battlefield. In the battlefield area, soldiers may be divided into a number of squads and fire teams with each one having its own mission, especially in some critical situation (e.g., a military response to an enemy attack or a sweep operation of houses). This situation may cause an unpredictable behavior in terms of wireless network topology state, thus increasing the susceptibility of network topology to decomposition in multiple components. This paper presents a Group Mobility Model simulating realistic battlefield behaviors and movement techniques. We also analyze wireless communication between dismounted soldiers and their squad leader deployed in a mobile ad hoc network (MANET) under different packet sending rate and perturbation factor modeled as a standard deviation parameter which may affect soldiers' mobility. A discussion of results follows, using several performance metrics according to network behavior (such as throughput, relaying rate of unrelated packets and path length).

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There has been an increasing interest in the issue of real-time path planning based on the exchange of information about traffic conditions in vehicular ad hoc networks (VANETs). Because of the development in hardware, software, and communication technologies. However, real-time applications are facing several challenges for providing reliable communications (V2V and V2I) due to many effective factors that includes highspeed mobility and sparse vehicle density on the which increase the rate of topology change. In this paper, we first establish a real-time path planning application which utilizes real-time information about traffic conditions for providing shortest paths with minimum travel time on a weighted graph which is extracted from a real map. This application utilizes vehicular ad hoc networks (VANETs) to enable real-time communications among vehicles, roadside units (RSUs), and a central server. Each vehicle can request a shortest-path by sending a simple request packet to the server and waits for a reply. Finally, our path-planning method is implemented and simulated by using Veins framework (with IEEE 802.11 p/WAVE standard). Veins is capable of running OMNET++ and SUMO in parallel. Simulation results confirm that our proposed path-planning approach improves significantly the travel time.

Vehicle-to-vehicle communication is a very actual and challenging topic which attracts a considerable attention from there search community. Vehicles are able to exchange information within these networks without the need of installing any infrastructure along the road side. To evaluate a Vehicular Ad Hoc Networks (VANETs) in traffic city, we present a simple model of simulation based on a Cellular Automaton technique specified by the rules which control communication exchange and the mobility of vehicles. Moreover, in a Cellular Automaton, space and time are divided into discrete cells and steps which can reduces the complexity of the system and cost of deployment. The model used here is based on the cellular automata(CA) model proposed by Biham-Middleton-Levine(BML). It considers two kinds of drivers which obeys the traffic light rules. Each vehicle generates an amount of data and hope to send it to the base station (BS) located in the middle of the network. In this work, we examine the performance of VANET in terms of average throughput. Simulation results show that the traffic patterns have an important impact over data communication at the base station as well as in the whole capacity of the communication network.

Wireless sensor networks (WSN) are considered to be a promising concept for enabling numerous categories of applications for both civil and military applications. This can include dismounted soldiers teams, group of animals or a group of mobile robots, where agents are moving collectively and sharing the same goal (e.g., destination, source of food or location of enemy). In this paper, we investigate the impact of dynamic agents based on a flock mobility model on the efficiency of wireless communications. We consider N mobile sensor agents capable of sensing and sending data packets periodically towards a base station (leader agent) directly or via intermediate nodes (relay nodes). At each time period, a sensor node can verify if an event is sensed based on a probability approach and then generates a data packet that is to be sent towards the destination, or else a sensor node can act as a relay node to forward data packets from other nodes. We evaluate the performance of the sensor nodes network under varying levels of perturbation of the collective motion of agents. The performance metrics observed are the residual energy, the number of sensors nodes still alive, the average normalized velocity, the packet delivery ratio, the end-to-end delay, and the average number of hops. Simulation results confirm that the dynamic agents have a significant impact on both the sensor network lifetime and the reachability of communications.