1,721,019 research outputs found
Marine GIS development: mapping the Bay of Naples
No full textThe primary goal of our GIS design for marine applications is to facilitate the surveyor in environmental data acquisition and in retrieving, preprocessing and visualizing georeferenced information from oceanographic cruises. The system called OSIRIS (ocean survey integrated research information system) has a modular architecture tailored to support environmental data acquisition. It provides a framework where updating and expanding each module is straightforward. An on-going program of seafloor mapping in Naples Bay (southeastern Tyrrhenian margin) is among the main research projects of the Geomare sud Institute, CNR. Financed by the National Geological Survey of Italy (CARG project), this research aims at producing, during the years 1998-2000, geological maps of selected marine coastal zones at the 1: 50.000 scale. OSIRIS has been used and tested in this frame and in particular during two oceanographic cruises organized by the Geomare Sud and by other institutions during the 1997-1998 time span
A comparison of numerical methods for solving diffusion-reaction equations in air quality models
No full textPacket loss recovery in audio multimedia streaming by using compressive sensing
No full textThe aim of this study is to introduce a new scheme, based on a compressive sampling technique, for the reconstruction of lost data in multimedia streaming. The audio streaming data are encapsulated in different packets, at the sender, by using an interleaving technique. The compressive sampling technique is used to recover audio information in case of lost packets, at the receiver. Experimental results are presented for speech and musical audio signals which illustrate the performances and the capabilities of the proposed methodology
Application of a parallel Air Quality model to the Campania region
No full textDuring most of the year, the concentrations of both primary and secondary air pollutants over the Campania region (southern Italy) do not comply with the Italian air quality standards. To gain insight into the chemical and meteorological processes that lead to high air pollutant concentrations over this area, the parallel package PNAM (Parallel Naples Airshed Model) has been developed, for the numerical simulation of photosmog episodes on urban and regional scale domains. PNAM has been applied to a photosmog episode which occurred on 26 July 1995. On this day, due to the stagnant conditions and the intensive solar radiation, a high ozone concentration was reported for the Naples basin. The performance of PNAM has been assessed by comparing measured air quality data with simulated data for O3, NO, NO2 and CO. PNAM was able to reproduce temporal and spatial characteristics of measured air quality data, although some discrepancies were evident, probably mainly due to the emission inventory, which was based only on total annual emissions. (C) 2000 Elsevier Science Ltd.
During most of the year, the concentrations of both primary and secondary air pollutants over the Campania region (southern Italy) do not comply with the Italian air quality standards. To gain insight into the chemical and meteorological processes that lead to high air pollutant concentrations over this area, the parallel package PNAM (Parallel Naples Airshed Model) has been developed, for the numerical simulation of photosmog episodes on urban and regional scale domains. PNAM has been applied to a photosmog episode which occurred on 26 July 1995. On this day, due to the stagnant conditions and the intensive solar radiation, a high ozone concentration was reported for the Naples basin. The performance of PNAM has been assessed by comparing measured air quality data with simulated data for O3, NO, NO2 and CO. PNAM was able to reproduce temporal and spatial characteristics of measured air quality data, although some discrepancies were evident, probably mainly due to the emission inventory, which was based only on total annual emissions
Seeking for the rational basis of the ‘Median Model’: a way to optimally combine multi-model ensemble results
No full textIn this paper we present an approach for the statistical analysis of multi-model ensemble results. The models considered here are operational long-range transport and dispersion models, also used for the real-time simulation of pollutant dispersion or the accidental release of radioactive nuclides. We first introduce the theoretical basis (with its roots sinking into the Bayes theorem) and then apply this approach to the analysis of model results obtained during the ETEX-1 exercise. We recover some interesting results, supporting the heuristic approach called "median model", originally introduced in Galmarini et al. (2004a, b). This approach also provides a way to systematically reduce (and quantify) model uncertainties, thus supporting the decision-making process and/or regulatory-purpose activities in a very effective manner
A preliminary study on remote optical observation of biomass burning using potassium signature
No full textA mathematical model of collaborative reputation systems
No full textThis paper provides a mathematical framework for modelling collaborative reputation systems (CRSs), which are useful in many fields of electronic commerce. A CRS is an algorithm that, at discrete points in time, receives in input from a set of users some ratings of a set of objects and generates a reputation for both the raters and the evaluated objects. Sufficient conditions for the convergence of a CRS are given, using basic results of the fixed point theory, and in particular for a broad class of iterative filtering methods and their related CRSs, generalizing some previous results. Finally, we analyse a simple kind of CRS which allows to use a priori information on the reliability of a subset of raters. Experimental results provide evidence that such CRSs exhibit high level of robustness against unfair raters
Compressive sampling and adaptive dictionary learning for the packet loss recovery in audio multimedia streaming
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