Search results for " rando"

showing 10 items of 498 documents

Modeling Macroalgal Forest Distribution at Mediterranean Scale: Present Status, Drivers of Changes and Insights for Conservation and Management

2020

Macroalgal forests are one of the most productive and valuable marine ecosystems, but yet strongly exposed to fragmentation and loss. Detailed large-scale information on their distribution is largely lacking, hindering conservation initiatives. In this study, a systematic effort to combine spatial data on Cystoseira C. Agardh canopies (Fucales, Phaeophyta) was carried out to develop a Habitat Suitability Model (HSM) at Mediterranean scale, providing critical tools to improve site prioritization for their management, restoration and protection. A georeferenced database on the occurrence of 20 Cystoseira species was produced collecting all the available information from published and grey lit…

Settore BIO/07 - EcologiaCystoseira canopies; Habitat suitability model; Mediterranean Sea; Random Forest; Species distribution0106 biological scienceslcsh:QH1-199.5Settore BIO/07Distribution (economics)Ocean Engineeringlcsh:General. Including nature conservation geographical distributionAquatic ScienceCystoseira canopieOceanography010603 evolutionary biology01 natural sciencesMediterranean scaleBrown algae -- Mediterranean seeAlgues brunes -- Distribució geogràficaMediterranean seaMarine resources -- Management -- Mediterranean SeaMediterranean Seamedia_common.cataloged_instance14. Life underwaterEuropean unionlcsh:ScienceAlgues brunes -- Mediterrània MarSpecies distributionWater Science and Technologymedia_commonGlobal and Planetary ChangeRandom ForestMarine ecology -- Mediterranean Seabusiness.industrySettore BIO/02 - Botanica Sistematica010604 marine biology & hydrobiologyEnvironmental resource managementMarine habitats -- Mediterranean Sea15. Life on landHabitat suitability model (HSM)Geography13. Climate actionSettore BIO/03 - Botanica Ambientale E Applicatalcsh:QCystoseira canopies habitat suitability model Mediterranean Sea Random Forest species distributionCystoseira canopiesbusinessHabitat suitability modelMarine algae -- Mediterranean SeaBrown algae -- Geographical distributionFrontiers in Marine Science
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Rateless Codes Performance Analysis in Correlated Channel Model for GEO Free Space Optics Downlinks

2012

Settore ING-INF/03 - TelecomunicazioniFree Space Optics (FSO) technologies for satellite communications offer several advantages: wide bandwidth high rate capability immunity to electromagnetic interference and small equipment size. Thus they are suitable for inter-satellite links deep space communications and also for high data rate ground-to-satellite/satellite-to-ground communications. Nevertheless FSO links suffer impairments that cause power signal degradation at the receiver. Scattering and absorption cause power signal attenuations predictable by suitable deterministic models. Optical turbulence causes random irradiance fluctuations which can generate signal fading events and can thereby only be predicted by statistical models. Attenuation and fading events can corrupt FSO links and so it would be recommended to add mitigation error codes on the communication link. FSO channel can be described as an erasure channel: fading events can cause erasure errors. We have identified in rateless codes (RCs) a suitable solution to be employed in FSO links. RCs do not need feedback and they add a redundant coding on the source data that allows the receiver to recover the whole payload despite erasure errors. We implemented two different of rateless codes: Luby Transform (LT) and Raptor. We analyzed their performances on a simulated turbulent GEO FSO downlink (1 Gbps - OOK modulation) at a 106 μm wavelength and for different values of zenith angles. Assuming a plane-wave propagation and employing Hufnagel-Valley we modeled the downlink using: 1) a temporal correlated channel model based on Gamma-Gamma probability distribution and 2) an irradiance covariance function that we converted on a time function using Taylor frozen eddies hypothesis. Our new channel model is able to simulate irradiance fluctuations at different turbulence conditions as it will be shown in the full paper. We will also report performance results of LT and Raptor codes at overhead range varying between 0 and 50% and for different values of source packets.Settore ING-INF/01 - Elettronica
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Secure random number generation in wireless sensor networks

2011

The increasing adoption of wireless sensor networks as a flexible and inexpensive tool for the most diverseapplications, ranging from environmental monitoring to home automation, has raised more and more atten-tion to the issues related to the design of specifically customized security mechanisms. The scarcity ofcomputational, storage, and bandwidth resources cannot definitely be disregarded in such context, and thismakes the implementation of security algorithms particularly challenging. This paper proposes a securityframework for the generation of true random numbers, which are paramount as the core building blockfor many security algorithms; the intrinsic nature of wireless sensor nodes …

Settore ING-INF/05 - Sistemi Di Elaborazione Delle InformazioniLeader electionleader election random numbers generation wireless sensor networksRandom number generationbusiness.industryComputer scienceDistributed computingKey distribution in wireless sensor networksTrue random numbers generatorRobustness (computer science)Mobile wireless sensor networknetwork securityWirelessbusinesswireless sensor networksWireless sensor networkRandomnessComputer Science::Cryptography and SecurityComputer network
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A TRNG Exploiting Multi-Source Physical Data

2010

In recent years, the considerable progress of miniaturization and the consequent increase of the efficiency of digital circuits has allowed a great diffusion of the wireless sensor network technology. This has led to the growth of applications and protocols for applying these networks to several scenarios, such as the military one, where it is essential to deploy security protocols in order to prevent opponents from accessing the information exchanged among sensor nodes. This paper analyzes security issues of data processed by the WSN and describes a system able to generate sequences of random numbers, which can be used by security algorithms and protocols. The proposed True Random Number G…

Settore ING-INF/05 - Sistemi Di Elaborazione Delle InformazioniRandom number generationbusiness.industryNetwork securityComputer scienceDistributed computingNode (networking)Cryptographic protocolTrusted third partyKey distribution in wireless sensor networksWireless Sensor Networks Random Number Generator Network SecurityNISTbusinessWireless sensor networkComputer network
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rec. a E. Onufrio, "Scritti letterari e saggi di varia umanità"

2010

Si tratta della ripubblicazione, accompagnata da un’accurata introduzione, di alcuni scritti del narratore e giornalista scapigliato Enrico Onufrio, vero esempio d’intellettuale moderno, maestro di stile e attento conoscitore delle nuove esigenze del pubblico, che in una brillante prosa giornalistica dà prova delle sue doti di ‘critico militante’.

Settore L-FIL-LET/10 - Letteratura Italianascapigliatura onufriu rando
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Iterated Conditionals, Trivalent Logics, and Conditional Random Quantities

2022

We consider some notions of iterated conditionals by checking the validity of some desirable basic logical and probabilistic properties, which are valid for simple conditionals. We consider de Finetti’s notion of conditional as a three-valued object and as a conditional random quantity in the betting framework. We recall the notions of conjunction and disjunction among conditionals in selected trivalent logics. Then, we analyze the two notions of iterated conditional introduced by Calabrese and de Finetti, respectively. We show that the compound probability theorem and other basic properties are not preserved by these objects, by also computing some probability propagation rules. Then, for …

Settore MAT/06 - Probabilita' E Statistica MatematicaCoherence Conditional events Conditional random quantities Conditional previsions Conjoined and disjoined conditionals Iterated conditionals Compound probability theorem Lower and upper bounds Import-export principle
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Connexive Logic, Probabilistic Default Reasoning, and Compound Conditionals

2023

We present two approaches to investigate the validity of connexive principles and related formulas and properties within coherence-based probability logic. Connexive logic emerged from the intuition that conditionals of the form if not-A, then A, should not hold, since the conditional’s antecedent not-A contradicts its consequent A. Our approaches cover this intuition by observing that the only coherent probability assessment on the conditional event A | not-A is p(A | not-A) = 0. In the first approach we investigate connexive principles within coherence-based probabilistic default reasoning, by interpreting defaults and negated defaults in terms of suitable probabilistic constraints on con…

Settore MAT/06 - Probabilita' E Statistica MatematicaCoherence Compounds of conditionals Conditional events Conditional random quantities Connexive principles Default reasoning Iterated conditionals Probability logic.Settore MAT/01 - Logica Matematica
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Algebraic aspects and coherence conditions for conjunctions among conditional events

2018

We deepen the study of a notion of conjunction among conditional events, introduced in previous papers in theframework of coherence. This notion of conjunction, differently from other approaches, is given in the setting ofconditional random quantities. We show that some well known properties which are satisfied by conjunctionsof unconditional events are also satisfied by conjunctions of conditional events. In particular we examine anadditive property and a decomposition formula, by also obtaining a generalized inclusion-exclusion formula. Then,by exploiting the notion of conjunction, we introduce the set of constituents generated bynconditional events.Moreover, under logical independence, w…

Settore MAT/06 - Probabilita' E Statistica MatematicaCoherenceconditionalevents conditional random quantities conjunction disjunction decomposition formula conditional constituents inclusion-exclusion formula distributive property.
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Logical Operations among Conditional Events: theoretical aspects and applications

2019

We generalize the notions of conjunction and disjunction of two conditional events to the case of $n$ conditional events. These notions are defined, in the setting of coherence, by means of suitable conditional random quantities with values in the interval $[0,1]$. We also define the notion of negation, by verifying De Morgan's Laws. Then, we give some results on coherence of prevision assessments for some families of compounded conditionals and we show that some well known properties which are satisfied by conjunctions and disjunctions of unconditional events are also satisfied by conjunctions and disjunction of conditional events. We also examine in detail the coherence of the prevision a…

Settore MAT/06 - Probabilita' E Statistica MatematicaConditional events conditional random quantities conjunction disjunction negation coherent prevision assessments coherent extensions quasi conjunction probabilistic reasoning p-entailment inference rules iterated conditionals System P.
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Generalized coherence and connection property of imprecise conditional previsions.

2008

In this paper we consider imprecise conditional prevision assessments on random quantities with finite set of possible values. We use a notion of generalized coherence which is based on the coherence principle of de Finetti. We consider the checking of g-coherence, by extending some previous results obtained for imprecise conditional probability assessments. Then, we study a connection property of interval-valued gcoherent prevision assessments, by extending a result given in a previous paper for precise assessments.

Settore MAT/06 - Probabilita' E Statistica MatematicaConditional random quantities; imprecise prevision assessments; generalized coherence; checking of g-coherence; connection property.Conditional random quantitiesimprecise prevision assessmentsconnection propertyConditional random quantities imprecise prevision assessments generalized coherence checking of g-coherence connection property.checking of g-coherencegeneralized coherence
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