87,061 research outputs found
Dirichlet integrals and Steiner asymmetry
No full textAbstractThe asymmetry of a Sobolev function u, measured as an integral distance from its Steiner symmetral us, is estimated in terms of the gap between the Dirichlet integrals of u and us
Receiver Design for Filter-Bank Multicarrier Systems Over Time-Frequency Selective Channels
No full textThis paper deals with receiver design issues for filter-bank multicarrier burst transmission over time- and frequency selective fading channels, with emphasis on synchronization and channel estimation aspects. Specifically, the proposed symbol timing recovery algorithm relies on the transmission of a short known preamble, whilst carrier synchronization is implicitly carried out by a properly modified Bayesian channel estimation algorithm relying on pilot symbols uniformly spaced throughout the subcarriers. The above schemes are assessed and their impact on the receiver performance in terms of frame error rate is evaluated in typical mobile wireless channel conditions. In particular, the sensitivity of the receiver to a frequency offset affecting the input signal is investigated
Critical analysis of radiochemical methodologies for the assessment of sediment pollution and dynamics in the Lagoon of Venice
No full textAquatic sediments are the ultimate sink of wastes dispersed in freshwater and soil. They are therefore a useful tool for investigating
polluted ecosystems. Lagoon environments are very difficult to study due to their unstable morphology. Under these circumstances, even an
excellent environmental investigation of a restricted lagoon area would still be inadequate to appreciate the characteristics of the entire
system. The Venice lagoon is a very complex ecosystem whose morphology is complicated further by extensive anthropic intervention. A
good environmental representation of the area was obtained with a preliminary radiochemical survey of airborne radionuclides, a unique tool
in evaluating the homogeneity of the entire sedimentary system. It must be stressed, however, that the significance of the data depends
substantially on the use of qualified procedures. Based on this, a detailed study was carried out on selected homogeneous areas,
reconstructing the inventories and fluxes of pollutants in the sediments. In this work the radiochemical approach to the environmental study
of the Venice lagoon is examine
A Systemic and Cooperative Approach towards an Integrated Infomobility System at Regional Scale
No full textWith the term infomobility we refer to the broad range of Intelligent Transport Systems (ITS) information services. Despite the increasing efforts on development of infomobility services, it is recognized that they still show significant limitations in providing end users with reliable and seamless information. In this paper we argue that a systemic approach is needed to foster the growth of novel solutions for the delivery of integrated realtime and always-on infomobility services, to be seamlessly provided across different transport operators, modes and geographical areas. The proposed approach conceived and implemented within the ongoing SIMob research project in Tuscany Region (Italy) relies on the definition of an Open Working Environment, i.e. a socio-technical environment whose objective is to facilitate the co-operation of stakeholders to foster the growth of an integrated infomobility system at regional scale. Its main constituents are: a Cooperative Network of stakeholders, including regional and national subjects from Public Administrations, Enterprises and Research Bodies; an Architectural Framework, providing the reference technological baseline enabling the rapid configuration and deployment of different technological capabilities
GEMOM Middleware Self-healing and Fault-tolerance: a Highway Tolling Case Study
No full textApplication of message-oriented communication in business critical systems has to cope with requirements for end-to-end intelligence, security, scalability, self-adaptation and fault-tolerance. To this extent, the Genetic Message-Oriented Middleware (GEMOM) European Research Project focused on the design and development of a fast-forwarding message oriented middleware, endowed with robustness, resilience, self-adaptability, and scalability capabilities. This paper reports on the design, development and testing results of a case study for the GEMOM middleware on highway toll data management and collection. The case study has a twofold objective: first, it offers a reference scenario that poses requirements challenging a specific set of self-healing and fault-tolerance GEMOM features and thus providing an application scenario suitable for features validation; second, it aims at representing a real-world application scenario and consequently at providing valuable insights on GEMOM exploitability in a specific market sector
Allozyme diversity of European freshwater crayfish of the genus Austropotamobius.
No full textData are reported on genetic variation at 30 enzyme loci in Austropotamobius crayfish from France, England, Italy, Spain, and the Balkans. Three population groups were detected, corresponding to A. torrentium, A. pallipes and A. italicus (sensu KARAMAN, 1962). Reproductive isolation between these three taxa was demonstrated in the field. Populations from England, France, and north-western Italy belong to A. pallipes sensu stricto, those from the rest of Italy, Spain, western Slovenia and north-western Croatia belong to A. italicus, whereas A. torrentium was found in the Balkans up to the Italian border. An average D-Nei of 0.30 was found between A. pallipes and A. italicus, while the average genetic distance between these two species and A. torrentium was D-Nei = 0.77. Populations of A. italicus from Spain and north-central Apennines were found to be genetically closely related (D-Nei = 0.05), not supporting a subspecific rank for these populations (A. j. lusitanicus). Marked interpopulation genetic diversity was observed both within A. italicus (average F-ST = 0.80, D-Nei up to 0.18), and within A. torrentium (average F-ST = 0.73, D-Nei UP to 0.14), comparable to that previously reported for A. pallipes. Such genetic heterogeneity appears mainly related to range fragmentations and subsequent recolonizations from multiple refugia during the last glacial events. Overall low values of genetic variability were found in the samples tested (e.g. H-e from 0 to 0.05), with the highest values in larger sized populations from less disturbed areas (e.g. in A. italicus from Spain and Slovenia). The genetic erosion observed in Austropotamobius populations stresses the need to restore their genetic variability, e.g. by controlled restocking, for successful programs of recovery and management of these endangered crayfish
I Lepidotteri Ropaloceri della Riserva Statale di Popolamento Animale "Lago di Burano" (Capalbio, Grosseto).
No full textduring 2007-2009 we surveyed rhopalocerans in the Riserva Statale di Popolamento animale “Lago di Burano” (southern Tuscany). We
found fifty species, some of which are widespread and common (Pieris brassicae, Colias crocea, Polyommatus icarus, Lasiommata megera,
Pieris rapae, Gonepteryx cleopatra, Maniola jurtina, Coenonympha pamphilus, Papilio machaon, Limenitis reducta and Kanetisa circe),
but others, such as Thymelicus acteon, Gegenes nostrodamus, Zerynthia cassandra, Lycaena thersamon, Charaxes jasius, Libythea celtis,
Hipparchia fagi and Hipparchia statilinus, are threatened. The main threats to rhopalocerans in the reserve are vegetation and water control
in agriculture. To reduce the impact of agriculture it is suggested: i) to maintain a strip of uncultivated land at least 20 m wide around the
lake and a belt of vegetation 2-4 m wide along channels and ditches; ii) to conserve hedges and shrubs; iii) to cut herbaceous plants in december
or January
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