564 research outputs found

    In-vehicle stereo vision system for identification of traffic conflicts between bus and pedestrian

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    Abstract The traffic conflict technique (TCT) was developed as "surrogate measure of road safety" to identify near-crash events by using measures of the spatial and temporal proximity of road users. Traditionally applications of TCT focus on a specific site by the way of manually or automated supervision. Nowadays the development of in-vehicle (IV) technologies provides new opportunities for monitoring driver behavior and interaction with other road users directly into the traffic stream. In the paper a stereo vision and GPS system for traffic conflict investigation is presented for detecting conflicts between vehicle and pedestrian. The system is able to acquire geo-referenced sequences of stereo frames that are used to provide real time information related to conflict occurrence and severity. As case study, an urban bus was equipped with a prototype of the system and a trial in the city of Catania (Italy) was carried out analyzing conflicts with pedestrian crossing in front of the bus. Experimental results pointed out the potentialities of the system for collection of data that can be used to get suitable traffic conflict measures. Specifically, a risk index of the conflict between pedestrians and vehicles is proposed to classify collision probability and severity using data collected by the system. This information may be used to develop in-vehicle warning systems and urban network risk assessment

    A Collaborative System to Manage Information Sources Improving Transport Infrastructure Data Knowledge

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    The present paper describes the WIKI RoadSMap project implemented within a start-up research program. The main objective of the project is to create a system that applies innovative technologies to information gathered to enable the acquisition of greater local knowledge and analysis of issues related to road infrastructure and directly and indirectly connected elements. By applying semantic analysis technology for the extraction, collection, integration and publication of data, WIKI RoadSMap allows users to acquire greater knowledge in order to optimize choices related to road infrastructure. The system allows more detailed and targeted dissemination of data related to the design, management and maintenance of an infrastructure. The source and type of data needed are different and heterogeneous, including information 'posted' by people with private and/or commercial purposes, or available at road agencies and/or public administrations or related to specific surveys carried out. The system platform should be available on the Web and on smartphones, both providing different levels of access and subscriptions. The spread and use of WIKI RoadSMap could have a positive impact on the market with regard to the supply of materials and specialized technical skills and companies operating in the areas of interest

    Structural health monitoring of asphalt pavements using smart sensor networks: A comprehensive review

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    Abstract Early, effective and continuous monitoring allows to reduce costs and to extend life of road infrastructure. For this reason, over the years, more and more efforts have been made to implement more advanced and effective monitoring systems at ever more contained costs, going from impractical manual and destructive methods through automated in vehicle equipment to the most recent wireless sensor network (WSN) embedded into the pavement. The purpose of this paper is to provide a comprehensive, up-to-date critical literature review of wireless sensor networks for pavement health monitoring, considering, also, the experience gained for wired sensor as fundamental point of reference. This work presents both the methodology used to collect and analyse the current bibliography and provides a description and comments fundamental characteristics of wireless sensor networks for pavement monitoring for damage detection purposes, among which energy supply, the detection method, the hardware and network architecture and the performance validation procedures. A brief analysis of other possible complementary applications of smart sensor networks, such as traffic and surface condition monitoring, is provided. Finally, a comment is provided on the gaps and possible directions that future research could follow to allow the extensive use of wireless sensor networks for pavement health condition monitoring

    Oxidative N-Heterocyclic Carbene Catalysis

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    N-Heterocyclic carbene (NHC) catalysis is a by now consolidated organocatalytic platform for a number of synthetic (asymmetric) transformations via diverse reaction modes/intermediates. In addition to the typical umpolung processes involving acyl anion/homoenolate equivalent species, implementation of protocols under oxidative conditions greatly expands the possibilities of this methodology. Oxidative NHC-catalysis allows for oxidative and oxygenative transformations through specific manipulations of Breslow-type species depending upon the oxidant used (external oxidant or O2/air), the derived NHC-bound intermediates paving the way to non-umpolung processes through activation of carbon atoms and heteroatoms. This review is intended to update the state of the art in oxidative NHC-catalyzed reactions that appeared in the literature from 2014 to present, with a strong focus to crucial intermediates and their mechanistic implications

    4D Printing of Plasmon-Encoded Tunable Polydimethylsiloxane Lenses for On-Field Microscopy of Microbes

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    Here the 4D printing of a magnifying polydimethylsiloxane (PDMS) lens encoded with a tunable plasmonic rejection filter is reported. The lens is formed by moldless printing of PDMS pre-polymer on a nanostructured porous silicon (PSi) templating layer. A nanometer-thick plasmonic filter is integrated on the lens surface by in situ synthesis of Ag and Au nanoparticles (NPs) with programmed density. The filter can be designed to reject light at the plasmonic resonance wavelength of the NPs with an optical density tunable from 0 to 3 and retreive light at longer wavelengths with a pass-to-stop band ratio tunable from 0 to 60 dB. Swelling of PDMS in hexane and ether is used to change the NP density on the lens surface and modulate, in turn, the transmittance properties of the NP-decorated lens over 3 orders of magnitude. The plasmon-encoded lens is coupled to a commercial smartphone demonstrating: shaping of the emission spectrum of a white light-emitting diode to tune the color from yellow to purple; real-time bright-field and fluorescence microscopy of living microbes in water, namely, the auto-fluorescent green alga Chlorogonium sp. and the ciliated protozoan Euplotes daidaleos

    DG-CST (Disease Gene Conserved Sequence Tags), a database of human–mouse conserved elements associated to disease genes

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    The identification and study of evolutionarily conserved genomic sequences that surround disease-related genes is a valuable tool to gain insight into the functional role of these genes and to better elucidate the pathogenetic mechanisms of disease. We created the DG-CST (Disease Gene Conserved Sequence Tags) database for the identification and detailed annotation of human–mouse conserved genomic sequences that are localized within or in the vicinity of human disease-related genes. CSTs are defined as sequences that show at least 70% identity between human and mouse over a length of at least 100 bp. The database contains CST data relative to over 1088 genes responsible for monogenetic human genetic diseases or involved in the susceptibility to multifactorial/polygenic diseases. DG-CST is accessible via the internet at http://dgcst.ceinge.unina.it/ and may be searched using both simple and complex queries. A graphic browser allows direct visualization of the CSTs and related annotations within the context of the relative gene and its transcripts
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