Dominique Dhoutaut

Impact of radio propagation models in vehicular ad hoc networks simulations

Vehicular ad hoc networks use new protocols to enable security, services and other inventive applications to be run onboard many types of vehicles. In their design phase, those protocols and applications need to be extensively simulated but most of the work in the simulator field concentrates on the medium access and higher layer protocols. In this paper, through real world experimentations we first characterize the behavior of the channel regarding losses, we deduce a set of properties needed for lightweight models still producing relevant results. Then we implement them in a model we called shadowing-pattern which we finally use in a VANET distinctive scenario where it considerably modifies the results of a data propagation application.

Using an evolutionary algorithm to optimize the broadcasting methods in mobile ad hoc networks

A mobile ad hoc network (MANET) is a collection of mobile nodes communicating through wireless connections without any prior network infrastructure. In such a network the broadcasting methods are widely used for sending safety messages and routing information. To transmit a broadcast message effectively in a wide and high mobility MANET (for instance in vehicular ad hoc network) is a hard task to achieve. An efficient communication algorithm must take into account several aspects like the neighborhood density, the size and shape of the network, the use of the channel. Probabilistic strategies are often used because they do not involve additional latency. Some solutions have been proposed to make their parameters vary dynamically. For instance, the retransmission probability increases when the number of neighbors decreases. But, the authors do not optimize parameters for various environments. This article aims at determining the best communication strategies for each node according to its neighborhood density. It describes a tool combining a network simulator (ns-2) and an evolutionary algorithm (EA). Five types of context are considered. For each of them, we tackle the best behavior for each node to determine the right input parameters. The proposed EA is first compared to three EAs found in the literature: two well-known EAs (NSGA-II and SPEA2) and a more recent one (DECMOSA-SQP). Then, it is applied to the MANET broadcasting problem.

Efficient Simulation of Distributed Sensing and Control Environments

The rise of the Internet of Things raises many challenges among which is the ability to efficiently simulate a real 3D environment with intelligent objects able to sense and act. Furthermore, the apparition of micro-objects able to communicate forces such as a simulator to scale up in the number of simulated nodes. In this paper, we report the progresses made in the design of a new kind of simulator named VisibleSim. VisibleSim mixes a discrete-event core simulator with discrete-time functionnalities in the most efficient way so that simulations can scale up in numbers. Experiments show that VisibleSim can accurately and smoothly simulate 2 millions of nodes at a rate of 650k events/sec on a simple laptop.

Using Nano-wireless Communications in Micro-Robots Applications

The emergence of nano-electromagnetic communications based on graphene nano-antennas has opened new perspectives for communications between small things, referred as to the internet of micro-things or even as the internet of nano-things. However, these antennas make use of the Terahertz band which raises many problems like the absorption of entire range of the available bandwidth by any molecule. Meanwhile, recent advances have been made in the design and fabrication of micro-robots enabling formation of microrobots networks. Nano-antennas are an interesting way of communicating between micro-robots. We envision two types of benefits using integrated nano-antennas in micro-robots. First, nano-wireless communications could enhance existing applications enabling a greater communication distance in an ensemble and broadcasting facilities. Second, nanowireless communications can create new usage and new applications. This article presents a simulation framework for micro-robots using nano-wireless communications and an application being developed within our simulator.

Efficient Simulation Environment of Wireless Radio Communications in MEMS Modular Robots

Modular robots needs networking for coordination and it is particularly true for MEMS micro robots. A promising communication technology is nanowireless networking which could be integrated directly into MEMS micro robots, in our case, the catoms of the Claytronics project. A first step towards this objective is to design a wireless simulator able to deal with modular robots. This simulator called Vouivre is integrated in DPRSim a modular robot simulator developed by Intel Research. This paper describes Vouivre and its integration in DPRSim which is an interesting case of integrating different timelines in one simulator. Experiments validate our design and show the interest of using wireless communication in modular robots.

Programmable matter as a cyber-physical conjugation

Programmable matter i.e. matter that can change its physical properties, more likely its shape according to an internal or an external action is a good example of a cybermatics component. As it links a cyberized shape to real matter, it is a straight example of cyber-physical conjugation. But, this interaction between virtual and real worlds needs two elements. The first one is to find a way to represent the cyberized object using programmable matter and the second is to be able to adapt the matter to the cyberized changes. This article presents the progresses made in these two topics within the Claytronics project.

Coordination and Computation in Distributed Intelligent MEMS

Over the last decades, research on microelectromechanical systems (MEMS) has focused on the engineering process which has led to major advances. Future challenges will consist in adding embedded intelligence to MEMS systems to obtain distributed intelligent MEMS. One intrinsic characteristic of MEMS is their ability to be mass-produced. This, however, poses scalability problems because a significant number of MEMS can be placed in a small volume. Managing this scalability requires paradigm-shifts both in hardware and software parts. Furthermore, the need for actuated synchronization, programming, communication and mobility management raises new challenges in both control and programming. Finally, MEMS are prone to faulty behaviors as they are mechanical systems and they are issued from a batch fabrication process. A new programming paradigm which can meet these challenges is therefore needed. In this article, we present CO2Dim, which stands for Coordination and Computation in Distributed Intelligent MEMS. CO2DIM is a common project between France and Hong-Kong building a new programming environment which includes a language, based on a joint development of programming and control capabilities, a simulator and real hardware.

Large scale MEMS robots cooperative map building based on realistic simulation of nano-wireless communications

Abstract The Claytronics project has produced interesting hardware components like cylindric micro-robots called catoms and software models to enable the concept of programmable matter. One application is the use of several catoms linked together so that they can “walk”. These walkers can explore an area and thanks to electromagnetic wireless nano-networks, they can communicate with each other sharing the map of the place to explore. In this paper, we study the different parameters influencing the transmission quality of the map to a sink which uses both traditional wireless and wireless nano-communication networks.

Designing Smart Adaptive Flooding in MANET Using Evolutionary Algorithm

This paper deals with broadcasting warning / emergency messages in mobile ad hoc networks. Traditional broadcasting schemes tend to focus on usually high and homogeneous neighborhood densities environments. This paper presents a broadcasting protocol that locally and dynamically adapts its strategy to the neighborhood densities. The behavior of the protocol is tuned using various internal parameters. Multiple combinations of those parameters have been pre-computed as optimal solutions for a range of neighborhood densities, and the most relevant one is dynamically chosen depending on the locally perceived environment. The combinations were determined by coupling an evolutionary algorithm and a network simulator, using a statistically realistic radio-propagation model (Shadowing Pattern). This approach is compared with other probabilistic methods while broadcasting an emergency message in vehicular ad hoc networks with variable and heterogeneous vehicle densities. In such a context, it is expected from the network to enable each node to receive the warning message. The results show that our protocol covers the whole network, whereas other methods only have a probability of 0.57 to 0.9 to cover the entire network.

Parameter study and characterization of wireless nanonetworks through simulation

Nanowireless electro-magnetic communication networks in the Terahertz band have raised interest in the networking community these very last years. However, if detailed studies have been published on analytical modelling of these networks, no simulation have been run to study in detail the characteristics of the transmission medium. We have designed Vouivre, a standalone nanowireless simulator, which is interfaced with two micro-robots simulator DPRSim and VisibleSim. This paper describes briefly Vouivre and presents first metrics of the communication channel using a communication paradigm called TS-OOK (Time Spread On-Off Keying).