701 research outputs found

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

    Get PDF
    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

    Get PDF
    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

    Get PDF
    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

    Get PDF
    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

    Obstructive sleep apnea and heart disease: the biomarkers point of view.

    Get PDF
    Obstructive sleep apnea syndrome (OSAS) is a highly prevalent disorder. Important risk factors for this disease are represented by obesity, male gender, smoking, some endocrinological disturbances, alcohol intake, use of benzodiazepines, and craniofacial alterations. It is well known that OSAS is a frequent comorbidity as well as a relevant risk factor for cardiovascular diseases (CVD), especially in patients with hypertension, coronary artery disease (CAD), arrhythmias, and heart failure. Furthermore, therapy with continuous positive airway pressure devices (CPAP) has been shown to significantly reduce the incidence of serious cardiovascular consequences. Interactions between OSAS and the cardiovascular system (CVS) can eventually result mainly in coronary atherosclerosis. These two conditions are connected by a complex biomarkers network. An extensive overview of these pathways could be helpful to better understand the causes of cardiovascular impairment in patients with OSAS

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

    Get PDF
    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

    The effect of pharmacological treatment on ADMA in patients with heart failure.

    Get PDF
    Asymmetric dimethylarginine (ADMA) plays a crucial role in the arginine-nitric oxide (NO) pathway. NO plays an important role in controlling vascular tone and regulates the contractile properties of cardiac myocytes. The purpose of this study was to investigate the effect of pharmacological treatment on asymmetrical dimethylarginine (ADMA) plasma levels in patients with acute congestive heart failure (HF). Patients with symptomatic acute congestive HF (NYHA Class III-IV) and impaired left ventricular (LV) function (ejection fraction less than 40 percent) were included in the study. ADMA and SDMA concentrations were assessed before and after pharmacological treatment in 18 critically ill patients on the intensive care unit by high performance liquid chromatography. All patients received a complete pharmacological treatment (diuretics, digoxin, ACE-inhibitors or angiotensin receptor blockers, and nitroglicerin) for the treatment of acute congestive HF. ADMA plasma levels of critically ill patients were significantly higher after pharmacological treatment respect baseline values (pre-treatment). In critically ill patients with acute congestive HF acute renal impairment function and the modulation of NOS determine plasma ADMA/SDMA levels after therapy

    Humin Formation on SBA-15-pr-SO3H Catalysts during the Alcoholysis of Furfuryl Alcohol to Ethyl Levulinate: Effect of Pore Size on Catalyst Stability, Transport, and Adsorption

    Get PDF
    Herein, the alcoholysis of furfuryl alcohol in a series of SBA-15-pr-SO3H catalysts with different pore sizes is reported. Elemental analysis and NMR relaxation/diffusion methods show that changes in pore size have a significant effect on catalyst activity and durability. In particular, the decrease in catalyst activity after catalyst reuse is mainly due to carbonaceous deposition, whereas leaching of sulfonic acid groups is not significant. This effect is more pronounced in the largest-pore-size catalyst C3, which rapidly deactivates after one reaction cycle, whereas catalysts with a relatively medium and small average pore size (named, respectively, C2 and C1) deactivate after two reaction cycles and to a lesser extent. CHNS elemental analysis showed that C1 and C3 experience a similar amount of carbonaceous deposition, suggesting that the increased reusability of the small-pore-size catalyst can be attributed to the presence of SO3H groups mostly present on the external surface, as corroborated by results on pore clogging obtained by NMR relaxation measurements. The increased reusability of the C2 catalyst is attributed to a lower amount of humin being formed and, at the same time, reduced pore clogging, which helps to maintain accessible the internal pore space
    • …
    corecore