"OpenStreetMap kreira i pruža slobodne geografske podatke, kao sto su karte gradova i naselja svakome tko ih želi. Projekt je nastao iz razloga sto vecina karata za koje mislite da su slobodne za koristenje, ustvari imaju pravna ili tehnicka ogranicenja za njihovu uporabu, sto sprijecava ljude da ih koriste na kreativne, produktivne te neocekivane nacine."

Open Street Map

One of the main ideas in the area of intelligent transport systems is to use all possible information coming from vehicles and infrastructure, in order to make the system “smarter” and avoid potentially dangerous situations—collisions, accidents, bottleneck, etc. However, data are sometimes unreliable due to source and communication network quality, leading vehicles or even the whole system to wrong decisions. We present a generic method for detecting dangerous events on the road. To support unreliable data sources, it uses distributed data fusion. Moreover, to deal with network failures, it relies on a self-stabilizing generic distributed algorithm. Our method mixes measurements obtained from vehicle onboard sensors, as well as wireless sensors placed close to the road and connected to road side units. Each vehicle computes how confident it is about a potential dangerous event using both local and remote data. To evaluate our approach, we implemented it using a specific hardware and software platform. Moreover, we instantiated a simple, yet efficient application to detect icy roads, based on temperature measurements. Thanks to both in-lab and actual on-the-road experiments, we demonstrate the possibility to deduce proper results from unreliable data and, consequently, the correctness and usefulness of our approach.

/pdf/detecting-road-events-using-distributed-data-fusion-44e4aqr7ww.pdf

Detecting Road Events Using Distributed Data Fusion: Experimental Evaluation for the Icy Roads Case

In this paper, we present a protocol to collect data within a vehicular ad hoc network (VANET). In spite of the intrinsic dynamic of such network, our protocol simultaneously offers three relevant properties: (1) It allows any vehicle to collect data beyond its direct neighborhood (i.e., vehicles within direct communication range) using vehicle-to-vehicle communications only (i.e., the infrastructure is not required); (2) It tolerates possible network partitions; (3) It works on demand and stops when the data collection is achieved. To the best of our knowledge, this is the first collect protocol having these three characteristics. All that is chiefly obtained thanks to a specific tool, namely Operator ant, borrowed from the self-stabilization area which confers to our algorithm the nice property to recover by itself from topology changes. In addition to a theoretical proof of correctness, our protocol has been implemented and tested through the Airplug Software Distribution: Road and lab experiments are presented and discussed.

https://hal.archives-ouvertes.fr/hal-01008765/document

COL: A data collection protocol for VANET

Nowadays, inter‐vehicle and intra‐vehicle communication triggers the development of safety and non‐safety applications in Vehicular Adhoc NETworks (VANET). These applications need to be evaluated before the actual implementation. The performance of these applications is generally evaluated through indispensable tools such as simulators, emulators, and testbeds. Although simulators, emulators, and testbeds are available as open‐source or proprietary for VANET applications, finding the correct tool for the experiment is intriguing and challenging from the researcher's perspective. In this paper, our focus is to provide a comprehensive survey on the existing simulators, emulators, and real time testbeds based on technical specifications, capabilities, etc. To the best of our knowledge, there is no such an exhaustive survey that exists in the literature. Further, we developed a real time low‐cost VANET testbed on our institute campus to implement the VANET related projects.

A comprehensive survey on simulators, emulators, and testbeds for VANETs

The Theory of Belief Functions is a formal frame-work for reasoning with uncertainty that is well suited for rep-resenting unreliable information and weak states of knowledge. In a previous work, a distributed algorithm for computing data fusion on-the-fly has been introduced, avoiding gathering the data on a single node before computation. In this paper, we present an experimental study of its properties. This algorithm is self-stabilizing and runs on unreliable message passing networks. It converges in finite time whatever is the initialization of the system and for any unknown topology. First we explain the algorithm implementation on an unreliable message passing environment and we implement a simple use-case. Then, by experimenting with this distributed application on a realistic network emulator, we show its interest for enforcing local confidence using close nodes, saving bandwidth and warning dangers. Moreover, we focus on the interesting connections between the data fusion operator and the self-stabilizing properties and we highlight the importance of the discounting.

/pdf/experiments-with-self-stabilizing-distributed-data-fusion-4l0mmpa9ml.pdf

Experiments with Self-Stabilizing Distributed Data Fusion

Many applications and protocols are planned for the so-called Intelligent Transportation Systems (ITS). Most of them are supposed to work in dynamic networks, such as the vehicular ad hoc networks (VANET). However, designing and studying distributed applications and protocols in such networks is not easy. Analytical studies suffer from the lack of pertinent models. Simulations are often far from reality. Road experiments are generally limited, due to their complexity. In this paper, we present an environment that emulates the vehicular networks. It allows to reproduce road experiments without further developments of the studied prototypes. These protocols can be tested with more complex road traffic. The impact of the communication range and the dynamics of the network can be studied. Some comparisons with road tests and simulations show the advantage of such an emulation framework.

/pdf/vehicular-networks-emulation-20tl62o0zg.pdf

A. Buisset

Papers

Vehicular Networks Emulation