The aim of this work is to verify and demonstrate the possibility of using X-band radars to identify, discriminate, characterize and follow small floating aggregations of marine litter (Small Garbage Islands—SGIs) made up mainly of plastic debris. To this end, a radar measurement campaign was carried out on a series of controlled releases into the sea of SGI modules assembled in the lab using the waste collected along a beach near the port of Livorno, in Tuscany, where the X-band radar of the Institute of Bioeconomy (IBE) of the National Research Council (CNR) is installed. The results of this first measurement campaign, which are illustrated in this preliminary work, are of interest to the entire scientific community that operates in the field of macroplastics analysis and monitoring, opening a new experimental avenue for the use of X-band radars also to monitor plastic waste at sea. Furthermore, the results obtained suggest good prospects for the use of X-band radars also for the study of coastal hydrodynamics on a local scale as well as in areas where it would be difficult to carry out measurements employing other technologies.

Data sharing and access control management is one of the issues still hindering the development of decentralized online social networks (DOSNs), which are now gaining more research attention with the recent developments in P2P computing, such as the secure public ledger–based protocols (Blockchains) for monetary systems. In a previous work, we proposed an initial audit–based model for access control in DOSNs. In this article, we focus on enhancing the audit strategies and the privacy issues emerging from records kept for audit purposes. We propose enhanced audit and collaboration strategies, for which experimental results, on a real online social network graph with simulated sharing behavior, show an improvement in the detection rate of bad behavior of more than 50% compared to the basic model. We also provide an analysis of the related privacy issues and discuss possible privacy-preserving alternatives.

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The aim of this paper is to discuss the case of an extreme negative sea level phenomenon that occurred along Sicily Island's coasts (Italy). Sea level time series associated to six stations that are part of the Italian tide gauge network have been analysed. By deriving the tidal residual and by evaluating meteorological parameters' trends, it was possible to give an explanation to this phenomenon.

This work show the limits of the detection capacity of X-band radars, as the sea state changes, in order to identify, discriminate, characterize and track small floating aggregations of plastic marine litter (Small Garbage Island - SGIs). Two distinct radar measurement campaigns were conducted at sea of SGI modules assembled in the laboratory. The measurement were carried out respectively in conditions of calm sea, to test the system in ideal conditions, and in rough sea conditions. The data analysis confirmed the ability of the X-band radars to detect the aggregations of floating waste on the sea surface.