Link travel time estimation in urban areas by detectors and probe vehicles fusion

International audienceThis paper presents an approach to estimate link travel time in urban areas. This approach consists of a data fusion from underground loop detectors and probe vehicles equipped with global positioning system (GPS). This method is expected to be more accurate, reliable and robust than using either of these data sources alone. In this approach, an algorithm is developed. This algorithm is based on the unscented Kalman filter using vehicle counts and flows from loop detectors located at the end of every link, and travel time from probe vehicles. From these counts the average travel time is calculated using the "cumulative plot" method. Furthermore, in order to incorporate the GPS data, a map-matching method is used to associate a travel time to the appropriate link

Comment recueillir des informations de position provenant de véhicules traceurs

Cet exposé a pour objectif de présenter les principales technologies embarquées dans les véhicules traceurs et qui permettent de récolter des informations utiles à l’estimation des temps de parcours et à la modélisation du trafic. Les différentes méthodes d’acquisition comme le positionnement par satellites (GNSS), la téléphonie mobile (GSM) et d’autres capteurs comme le Bluetooth, seront présentées avec leurs caractéristiques pour le recueil de données spécifiques au trafic motorisé. L’exposé mettra l’accent sur les principaux avantages et inconvénients des méthodes et la qualité des données que les systèmes de recueil peuvent fournir pour les applications de gestion du trafic

SaPPART - Satellite Positioning Performance Assessment for Road Transport

Presentation of the COST Action TU 1302 SaPPART on Satellite Positioning Performance for Road Transport. SaPPART brings together experts in GNSS, ITS and mobility to address the open issues and guarantee the success of the standardisation for underpinning certification initiatives

SaPPART Guidelines, Performance assessment of positioning terminal

This deliverable, entitled guidelines, is the third outcome of SaPPART COST Action, a European network of scientists and stakeholders that aims to promote smart use of GNSS technology in the field of intelligent road transport and mobility. It discusses the performance assessment of the GNSS-based Positioning terminals (GBPT), which is generally under the responsibility of the system integrators in the road market of GNSS. The aim of this document is to provide guidelines for generic test procedures for the evaluation of GBPT performance, either by field tests, simulations or their combination, compliant with the concepts and the definitions already established in the SaPPART White Paper (TMI 1) and Handbook (TMI 2). The document is intended to provide the reader with a helpful tool for planning the GBPT testing procedures by both discussing the testing in general and by providing some detailed practical information

COST TU1302- SaPPART Handbook: Assessment of positioning performance in ITS applications

This handbook is the second deliverable of SaPPART COST Action, dedicated to performance issues, when positioning performance is essential to the fulfilment of the requirements of the whole ITS system. It starts by illustrating the non-straightforward nature of the role of positioning information in some emblematic applications and introduces a simulation method sensitivity analysis, as a tool to make the right choice of positioning terminal for a given application. Then, the Handbook discusses the error sources at the terminal level and introduces a model of the horizontal position error in an urban environment. In the final part, this error model and the sensitivity analysis are applied to two examples of ITS systems, namely Road User Charging and eCall, in order to illustrate how sensitive these systems are to the positioning performance

Comparative study of non-linear filtering techniques applied to real time 2D vehicle positioning

Comparative study of non-linear filtering techniques applied to real time 2D vehicle positioning. The general framework of the research investigations undertaken here concerns the positioning of vehicles for intelligent advanced driver assistance systems (ADAS). The functions foreseen in such applications, like navigation, driving assistance and cooperation with infrastructure will be much more advanced than what they are at present. For these applications, positioning requirement in term of accuracy is less that 1 meter, including in urban environment where one knows the limitations of satellites receivers. To do so, vehicles are equipped with additional sensors to be fused with GPS positions. The approach reported in this article deals with the problem of initialising the positioning filter, with nothing else than an odometer and a turn-rate gyroscope (in addition to the GPS receiver). An extended Kalman filter, four parallel Kalman filters, an unscented filter and a particle filter have been implemented, in real time, and their robustness is compared by the authors, particularly when the initial heading is unknown.Étude comparative des techniques de filtrage non-linéaire appliquées à la localisation 2D d'un véhicule en temps réel. Le contexte général des travaux rapportés dans cet article concerne la localisation de véhicules dans les systèmes d'aide à la conduite (ADAS), où les fonctionnalités de navigation, d'aide à la conduite et de coopération avec l'infrastructure seront bien plus avancées qu'aujourd'hui. Pour ces applications, la localisation vise une précision métrique, y compris en milieu urbain, où l'on connaît toute la difficulté de se positionner par satellites. Pour ce faire, les véhicules sont dotés de capteurs dont les mesures doivent être fusionnées avec le GPS. L'approche présentée ici apporte une solution originale au problème de l'initialisation du positionnement, sans autre capteur qu'un odomètre et un gyromètre de cap (en plus du récepteur GPS). Un filtre de Kalman étendu, quatre filtres de Kalman parallèles, un filtre sans parfum, et un filtre particulaire sont implémentés, en temps réel, et les auteurs les comparent sous l'angle de leur robustesse, notamment lorsque le cap initial est inconnu

ASaiM: A Galaxy-based framework to analyze microbiota data

Background: New generations of sequencing platforms coupled to numerous bioinformatics tools have led to rapid technological progress in metagenomics and metatranscriptomics to investigate complex microorganism communities. Nevertheless, a combination of different bioinformatic tools remains necessary to draw conclusions out of microbiota studies. Modular and user-friendly tools would greatly improve such studies. Findings: We therefore developed ASaiM, an Open-Source Galaxy-based framework dedicated to microbiota data analyses. ASaiM provides an extensive collection of tools to assemble, extract, explore, and visualize microbiota information from raw metataxonomic, metagenomic, or metatranscriptomic sequences. To guide the analyses, several customizable workflows are included and are supported by tutorials and Galaxy interactive tours, which guide users through the analyses step by step. ASaiM is implemented as a Galaxy Docker flavour. It is scalable to thousands of datasets but also can be used on a normal PC. The associated source code is available under Apache 2 license at https://github.com/ASaiM/framework and documentation can be found online (http://asaim.readthedocs.io). Conclusions: Based on the Galaxy framework, ASaiM offers a sophisticated environment with a variety of tools, workflows, documentation, and training to scientists working on complex microorganism communities. It makes analysis and exploration analyses of microbiota data easy, quick, transparent, reproducible, and shareable

Comparative genomics highlights the unique biology of Methanomassiliicoccales, a Thermoplasmatales-related seventh order of methanogenic archaea that encodes pyrrolysine

BACKGROUND: A seventh order of methanogens, the Methanomassiliicoccales, has been identified in diverse anaerobic environments including the gastrointestinal tracts (GIT) of humans and other animals and may contribute significantly to methane emission and global warming. Methanomassiliicoccales are phylogenetically distant from all other orders of methanogens and belong to a large evolutionary branch composed by lineages of non-methanogenic archaea such as Thermoplasmatales, the Deep Hydrothermal Vent Euryarchaeota-2 (DHVE-2, Aciduliprofundum boonei) and the Marine Group-II (MG-II). To better understand this new order and its relationship to other archaea, we manually curated and extensively compared the genome sequences of three Methanomassiliicoccales representatives derived from human GIT microbiota, “Candidatus Methanomethylophilus alvus", “Candidatus Methanomassiliicoccus intestinalis” and Methanomassiliicoccus luminyensis. RESULTS: Comparative analyses revealed atypical features, such as the scattering of the ribosomal RNA genes in the genome and the absence of eukaryotic-like histone gene otherwise present in most of Euryarchaeota genomes. Previously identified in Thermoplasmatales genomes, these features are presently extended to several completely sequenced genomes of this large evolutionary branch, including MG-II and DHVE2. The three Methanomassiliicoccales genomes share a unique composition of genes involved in energy conservation suggesting an original combination of two main energy conservation processes previously described in other methanogens. They also display substantial differences with each other, such as their codon usage, the nature and origin of their CRISPRs systems and the genes possibly involved in particular environmental adaptations. The genome of M. luminyensis encodes several features to thrive in soil and sediment conditions suggesting its larger environmental distribution than GIT. Conversely, “Ca. M. alvus” and “Ca. M. intestinalis” do not present these features and could be more restricted and specialized on GIT. Prediction of the amber codon usage, either as a termination signal of translation or coding for pyrrolysine revealed contrasted patterns among the three genomes and suggests a different handling of the Pyl-encoding capacity. CONCLUSIONS: This study represents the first insights into the genomic organization and metabolic traits of the seventh order of methanogens. It suggests contrasted evolutionary history among the three analyzed Methanomassiliicoccales representatives and provides information on conserved characteristics among the overall methanogens and among Thermoplasmat

SaPPART Guidelines: Assessment of positioning performance in ITS applications

This deliverable, entitled guidelines, is the third outcome of SaPPART COST Action, a European network of scientists and stakeholders that aims to promote smart use of GNSS technology in the field of intelligent road transport and mobility. It discusses the performance assessment of the GNSS-based Positioning terminals (GBPT), which is generally under the responsibility of the system integrators in the road market of GNSS. The aim of this document is to provide guidelines for generic test procedures for the evaluation of GBPT performance, either by field tests, simulations or their combination, compliant with the concepts and the definitions already established in the SaPPART White Paper (TMI 1) and Handbook (TMI 2). The document is intended to provide the reader with a helpful tool for planning the GBPT testing procedures by both discussing the testing in general and by providing some detailed practical information