269 research outputs found
Toward Scalable Docker-Based Emulations of Blockchain Networks
Blockchain, like any other technology, needs a strong testing methodology to support its evolution. Setting up meaningful blockchain tests is a notoriously complex task for several reasons: software is complex, large number of nodes are involved, network is non ideal, etc. Developers usually adopts small virtual laboratories or costly real devnets, based on real software. Researchers usually prefer simulations of a large number of nodes, based on simplified models. In this paper, we aim to obtain the advantages of both approaches, i.e., performing large, realistic, unexpensive, and flexible experiments, using real blockchain software within a virtual environment. To do that, we tackle the challenge of running large blockchain networks in a single physical machine, leveraging Linux and Docker. We analyze a number of problems that arise when large blockchain networks are emulated and we provide technical solutions for all of them. Finally, we describe our experience of emulating a fairly large blockchain network, comprising more than 3000 containers, for research purposes
Three years field trials to assess the effect of kaolin made particles and copper on olive-fruit fly (B.oleae Gmelin) infestations in Sicily
In most countries of Mediterranean Basin, Bactrocera oleae (Gmel), the olive fruit fly, is the key pest insect on olives. In Sicily this pest causes losses of fruits and a poor quality olive oil. Many researchers have recently carried out some field studies which were based on the use of kaolin and copper against the olive-fruit fly. In the last years these products have been effective several times in reducing olive fly infestation. Kaolin had, also, some important effect in reducing heat-stress in fruit crops and olive-trees.
The aim of the present study was to assess the effect of kaolin and copper treatment on olive infestations in Sicily and to evaluate chemical and sensory parameters of oils extracted. For this reason, within 2003-2005, the IX Servizio of Assessorato Regionale Agricoltura e Foreste, selected some olive groves where to carry out trials with kaolin and copper and to realize information and divulgation activities
Modelling the effect of environmental variables on the reproductive success of Griffon Vulture (Gyps fulvus) in Sardinia, Italy
Old World vultures are experiencing dramatic population declines and now are among
the species most threatened with extinction. Understanding the environmental variables
that can influence the reproductive indexes of vulture populations can facilitate both
habitat and species management. The aim of this study was to identify which environmental
variables primarily affect the breeding successes of the Griffon Vulture Gyps fulvus
in northern Sardinia by applying a Bayesian hierarchical model. A unique dataset of
reproductive records (197 nests monitored over 39 years for a total of 992 breeding
records) was used. Eight environmental and topographical variables describing the habitat
at the nesting sites were considered as potential predictors of breeding success. These
included mean annual temperature, mean annual precipitation, isothermality, elevation,
the normalized difference vegetation index, wind speed, and the aspect and slope of the
land surface. In addition, we also considered the effect of human disturbance and the
type of nest. According to our best model, the probability of successfully raising a chick
in Griffon Vultures was higher in nests exposed to a high wind speed, not covered by
natural shelters, where the vegetation was mostly represented by shrub and pastures,
with low human disturbance and in years with low rainfall. This model will be useful for
management of the breeding habitat and to identify the area most suitable for Griffon
Vulture reproduction. This information is crucial for programming conservation measures
aimed at enlarging the area of occupancy of the species.Postprin
Effects of vessel traffic on relative abundance and behaviour of cetaceans : the case of the bottlenose dolphins in the Archipelago de La Maddalena, north-western Mediterranean sea
Acknowledgements This study was part of the Tursiops Project of the Dolphin Research Centre of Caprera, La Maddalena. Financial and logistical support was provided by the Centro Turistico Studentesco (CTS) and by the National Park of the Archipelago de La Maddalena. We thank the Natural Reserve of Bocche di Bonifacio for the support provided during data collection. The authors thank the numerous volunteers of the Caprera Dolphin Research Centre and especially Marco Ferraro, Mirko Ugo, Angela Pira and Maurizio Piras whose assistance during field observation and skills as a boat driver were invaluable.Peer reviewedPostprin
Incorporating Biotic Information in Species Distribution Models: A Coregionalized Approach
In this work, we discuss the use of a methodological approach for modelling spatial
relationships among species by means of a Bayesian spatial coregionalized model. Inference and
prediction is performed using the integrated nested Laplace approximation methodology to reduce
the computational burden. We illustrate the performance of the coregionalized model in species
interaction scenarios using both simulated and real data. The simulation demonstrates the better
predictive performance of the coregionalized model with respect to the univariate models. The case
study focus on the spatial distribution of a prey species, the European anchovy (Engraulis encrasicolus),
and one of its predator species, the European hake (Merluccius merluccius), in the Mediterranean sea.
The results indicate that European hake and anchovy are positively associated, resulting in improved
model predictions using the coregionalized model.Postprin
Historical summer distribution of the endangered North Atlantic right whale (Eubalaena glacialis): a hypothesis based on environmental preferences of a congeneric species
Aim: To obtain a plausible hypothesis for the historical distribution of North Atlantic right whales (NARWs) (Eubalaena glacialis) in their summer feeding grounds. Previously widespread in the North Atlantic, after centuries of hunt- ing, these whales survive as a small population off eastern North America. Because their exploitation began before formal records started, information about their historical distribution is fragmentary
On-Chain Global Maintenance Services
Facility management deals with all activities that are not core business for a company and are consequently outsourced to specilized companies. Maintenance is a fundamental activity in facility management and it is often handled by Global Maintenance Services (GMS) where some maintenance activities are delegated by the company to service providers and are remunerated according to measurable results expressed as Key Performance Indicators. In this context, it would be desirable to have information systems trustable by all involved actors. In this paper, we discuss the design of a blockchain solution capable to support a GMS on-chain. We first introduce the GMS concept and how it is related to the Principal-Agent relationship, then we show a reference architecture to implement GMS on-chain. We discuss a use case of on-chain GMS in a hospital showing how smart contracts and oracles can be used in this context. We present the advantages of this approach and we discuss the open problems for realizing a proof-of-concep
Identifying the best fishing-suitable areas under the new European discard ban
The spatial management of fisheries has been repeatedly proposed as a discard mitigation measure. A number of studies have assessed the
fishing suitability of an area based on units of by-catch or discard per unit effort. However, correct identification of fishing-suitable areas
should assess biomass loss with respect to the benefits. This study therefore, proposes the analysis of by-catch ratios, which do represent benefit vs. loss and are standardized to a wide range of effort characteristics. Furthermore, our study proposes the use of two ratios: the proportion
of total unwanted biomass out of the total catch as an indicator of the overall ecological impact, and the proportion of unwanted but regulated species biomass as a proxy for the economic impact on fishers resulting from the new European discard ban that prohibits the discard
of regulated species. These discard ratios are modelled by means of a Bayesian hierarchical model, specifically, a spatio-temporal beta regression model, which has several advantages over the traditional arcsine transformation. Results confirm the standardizing capacity of by-catch
ratios across vessels and identify at least two economically fishing-suitable areas where discards ratios are minimized by reducing unwanted
catch
Decadal changes in biomass and distribution of key fisheries species on Newfoundland’s Grand Banks
Canadian fisheries management has embraced the precautionary approach and the incorporation
of ecosystem information into decision-making processes. Accurate estimation of
fish stock biomass is crucial for ensuring sustainable exploitation of marine resources. Spatio-
temporal models can provide improved indices of biomass as they capture spatial and
temporal correlations in data and can account for environmental factors influencing biomass
distributions. In this study, we developed a spatio-temporal generalized additive model (st-
GAM) to investigate the relationships between bottom temperature, depth, and the biomass
of three key fished species on The Grand Banks: snow crab (Chionoecetes opilio), yellowtail
flounder (Limanda ferruginea), and Atlantic cod (Gadus morhua). Our findings revealed
changes in the centre of gravity of Atlantic cod that could be related to a northern shift of the
species within the Grand Banks or to a faster recovery of the 2J3KL stock. Atlantic cod also
displayed hyperaggregation behaviour with the species showing a continuous distribution
over the Grand Banks when biomass is high. These findings suggest a joint stock assessment
between the 2J3KL and 3NO stocks would be advisable. However, barriers may need
to be addressed to achieve collaboration between the two distinct regulatory bodies (i.e.,
DFO and NAFO) in charge of managing the stocks. Snow crab and yellowtail flounder centres
of gravity have remained relatively constant over time. We also estimated novel indices
of biomass, informed by environmental factors. Our study represents a step towards ecosystem-
based fisheries management for the highly dynamic Grand Banks
Sea state monitoring by ship motion measurements onboard a research ship in the antarctic waters
A parametric wave spectrum resembling procedure is applied to detect the sea state parameters, namely the wave peak period and significant wave height, based on the measurement and analysis of the heave and pitch motions of a vessel in a seaway, recorded by a smartphone located onboard the ship. The measurement system makes it possible to determine the heave and pitch acceleration spectra of the reference ship in the encounter frequency domain and, subsequently, the absolute sea spectra once the ship motion transfer functions are provided. The measurements have been carried out onboard the research ship “Laura Bassi”, during the oceanographic campaign in the Antarctic Ocean carried out in January and February 2020. The resembled sea spectra are compared with the weather forecast data, provided by the global-WAM (GWAM) model, in order to validate the sea spectrum resembling procedure
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