1,721,118 research outputs found
Supporto Web 2.0 per un Laboratorio Virtuale
No full textI recenti progressi nel settore informatico offrono nuove possibilità in termini di interattività. L'obiettivo è sviluppare applicazioni web scalabili grazie a tecnologie quali virtualizzazione, workload mananagement e cloud computing. La virtualizzazione è oggi la chiave per aprire la porta del cloud computing. Il cloud computing espande le capacità di calcolo, senza ingenti investimenti in infrastrutture, di formazione o di licenza del software, soprattutto se si gestisce al meglio lo sviluppo delle applicazioni Web 2.0. L'intento del presente lavoro è quello di illustrare gli aspetti tecnologici che hanno caratterizzato le soluzioni individuate nel corso della nostra ricerca sperimentale per la creazione di un laboratorio virtuale basato sulle tecnologie cloud computing e web 2.0. La soluzione proposta consente, infatti, un mashup di diversi servizi indirizzati all'approccio collaborativo del lavoro e dell'apprendimento in rete di nuova generazion
GIOVE-A Initial Signal Analysis
No full textIn late December 2005 the GIOVE-A test satellite was launched by the European Space Agency (ESA) to secure the frequencies for the Galileo system and to provide a platform for testing the new navigation signals. We performed an initial assessment of these signals using the 30m deep space antenna of the DLR ground station in Weilheim (Germany). The antenna gain raised the signals above the noise level, thus allowing a detailed analysis even without knowledge of the ranging codes. The present paper covers the analysis of the L1/E1 signals, which includes a discussion of the spectrum, the time domain signal and a decoding of the spreading codes for the Open Service
The GIOVE-A Small Navigation Mission
Full text linkThe GIOVE-A mission demonstrates that small satellites are the ideal tool for rapid response missions. The 600kg spacecraft was launched into Medium Earth Orbit in late December 2005, carrying a navigation payload, technology payloads, and a space environment analysis package. Despite significant challenges in the space environment, and tight mission requirements, it was possible to use small satellite engineering techniques to develop and launch this demanding mission in under 30 months
Two traditional Reference Points based on the yield per recruit model, corrected by ecological and economic weights
No full textExperimental data on growth, mortality and reproduction of Ostrea edulis (L., 1758) in a semi-enclosed basin of the Mediterranean Sea
No full textBiometry, growth, survival and mortality rates as well as reproduction of O. edulis have been evaluated in the Taranto Sea, a semi-enclosed basin of the North-Western Ionian Sea (Mediterranean Sea). A crossed experimental design with 3 factors (container, depth and stocking density) was defined to investigate their effect on the sizes, growth performance, survival and mortality rates. Moreover, the reproduction was studied to better understand the life cycle of the species in the basin. The investigated experimental conditions caused significantdifferences inbothsizechangesandgrowthparameters. In particular, the density was the main factor influencing both biometry and growth. The oysters cultivated at low density showed L∞ (155.46±46.38mmDVL), k (0.42±0.25 year−1) andΦ′ (2.00) values significantly higher than those reared at high density L∞ (134.28±36.13 mm DVL), k (0.35±0.22 year−1) and Φ′ (1.80). The winter point (WP) occurred during winter and the strength of the seasonal oscillation (C) ranged between 0.10 and 0.37. No significant differences between the experimental rearing conditions were observed in either survival (S) or mortality (Z) rates. Oysters reared at low and high density showed mean S values equal to 0.88±0.03 and 0.89± 0.03, respectively as well as mean Z values equal to 0.13±0.03 and 0.12±0.04. Maturation of gonads occurred continuously during the year showing a slackening during summer when the highest temperatures were recorded in the water column. In addition, the highest percentages of fluent gonads were observed during winter. Histological analysis confirmed the macroscopic observation of gonads. In particular, gamete differentiation was observed during late autumn and early winter. An inverse correlation between the condition index and themean temperature in the water columnwas observed throughout the study period. The present results indicate an optimal crop age of about 2 years, corresponding to the commercial size of 8–9 cmdorsal–ventral length and weight of 55–60 g
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Initial radiation measurements from Europe's Galileo test-bed satellite, GIOVE-A
No full textIn preparation for deployment of the Galileo satellite navigation system, Europe has launched a test satellite, Giove-A. One of its objectives is to measure the radiation environment encountered in medium Earth orbit (MEO) which is a new regime for European missions. Giove-A therefore includes two radiation environment monitors: Merlin supplied by QinetiQ and CEDEX supplied by the University of Surrey. Merlin measures electrostatic charging and electron fluxes, total ionising dose, energetic proton fluxes and heavy ion linear energy transfer (LET) spectra. CEDEX monitors energetic proton fluxes, heavy ion linear energy transfer (LET) spectra and ionising dose rates. Giove-A, which was built by SSTL (UK), was successfully launched on 28th December 2005 into a 23,600 km circular, 56 degree inclination orbit. Data received since launch has been analysed and demonstrates that the MEO environment is highly dynamic due to the influence of space weather. Numerous electron belt enhancement events have been observed and the charging effects of these events been characterised. Total ionising dose is also seen to be delivered almost wholly during electron events
Accrescimento, longevità ed effetti della senescenza in Aristeus antennatus nel Mar Ionio
No full textAriann@ project: E-Learning Platform for University Guidance
No full textThe advent of Web 2.0 develops the concepts related to sociality and cooperation. The new network is more interactive and dynamic and has been revolutionizing traditional teaching/learning methods moving towards the so called e-learning 2.0. In this framework, our goal is to present a project based e-learning platform meeting Web 2.0 standards. The“Ariann@” project provides for a telematic platform targeted to university guidance services following the model of collaborative learning. A close analysis highlighted the absence of a product fully complying with the project requirements. To bridge this gap, user-user and platform-user collaboration media were integrated, through the development of synchronous communication techniques, into an open source learning environmen
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