Search results for " Probability distribution"

showing 10 items of 100 documents

Using plot soil loss distribution for soil conservation design

2011

Abstract Soil conservation design is generally based on the estimation of average annual soil loss but it should be developed taking into account storms of a given return period. However, use of frequency analysis in soil erosion studies is relatively limited. In this paper, an investigation on statistical distribution of soil loss measurements was firstly carried out using a relatively high number of simultaneously operating plots of different lengths, λ (11, 22, 33 and 44 m) at the experimental station of Sparacia (southern Italy). Using a simple normalization technique, the analysis showed that the probability distribution of the normalized soil loss is independent of both the scale leng…

Return periodHydrologyNormalization (statistics)Frequency analysisSoil erosion USLE probability distributions soil conservation practices designSoil scienceStormlaw.inventionSoil losslawEnvironmental scienceProbability distributionSettore AGR/08 - Idraulica Agraria E Sistemazioni Idraulico-ForestaliSoil conservationEarth-Surface Processes
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Output Feedback Control of Discrete Impulsive Switched Systems with State Delays and Missing Measurements

2013

Published version of an article in the journal: Mathematical Problems in Engineering. Also available from the publisher at: http://dx.doi.org/10.1155/2013/283426 Open Access This paper is concerned with the problem of dynamic output feedback (DOF) control for a class of uncertain discrete impulsive switched systems with state delays and missing measurements. The missing measurements are modeled as a binary switch sequence specified by a conditional probability distribution. The problem addressed is to design an output feedback controller such that for all admissible uncertainties, the closed-loop system is exponentially stable in mean square sense. By using the average dwell time approach a…

SequenceArticle Subjectlcsh:MathematicsGeneral MathematicsGeneral EngineeringBinary numberConditional probability distributionlcsh:QA1-939Expression (mathematics)Dwell timeExponential stabilitylcsh:TA1-2040Control theoryState (computer science)lcsh:Engineering (General). Civil engineering (General)MathematicsMathematical Problems in Engineering
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Analytical representation of bimodality in bivariate distribution of chain length and chemical composition of copolymers

2022

Abstract Tuning the bimodality of microstructural features in polymers has provided novel properties and applications. A classic example is to overcome the trade-off between processability and mechanical properties in polyolefins. A recent example is to decrease the interfacial tension in blending incompatible polymers. Therefore, the development of a bimodality index (BI), especially for the chain length distribution (CLD) and the chemical composition distribution (CCD), is crucial for the quantitative design of materials. This study introduces quantitative expressions for the bimodality of univariate CLD on the linear scale, and CCD. Moreover, we develop a bimodality criterion for bivaria…

Series (mathematics)General Chemical EngineeringUnivariateGeneral ChemistryBivariate analysisIndustrial and Manufacturing EngineeringBimodalityDistribution (mathematics)Joint probability distributionLinear scaleEnvironmental ChemistryStatistical physicsRepresentation (mathematics)MathematicsChemical Engineering Journal
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Evolved factor method for service life prediction of building components

2013

Key issues in the production process associated with construction are the implementation of quality and sustainability principles. Indeed, it is increasingly important in the maintenance of quality levels provided by materials, components and building structures, especially after the recent Regulation (EU) No. 305/2011. This document introduced the seventh requirement for the sustainable use of natural resources, guaranteeing the durability of construction products, thus being planned. The international standard for the assessment of durability of building materials and components is the ISO 15686 - Buildings and constructed assets - Service life planning, providing the definition of the Re…

Settore ICAR/11 - Produzione EdiliziaFactor method durability service life log-normal function probability distribution function
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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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TSVD as a Statistical Estimator in the Latent Semantic Analysis Paradigm

2015

The aim of this paper is to present a new point of view that makes it possible to give a statistical interpretation of the traditional latent semantic analysis (LSA) paradigm based on the truncated singular value decomposition (TSVD) technique. We show how the TSVD can be interpreted as a statistical estimator derived from the LSA co-occurrence relationship matrix by mapping probability distributions on Riemanian manifolds. Besides, the quality of the estimator model can be expressed by introducing a figure of merit arising from the Solomonoff approach. This figure of merit takes into account both the adherence to the sample data and the simplicity of the model. In our model, the simplicity…

Settore ING-INF/05 - Sistemi Di Elaborazione Delle InformazioniHellinger DistanceLatent semantic analysisComputer sciencebusiness.industryProbabilistic logicEstimatorStatistical modelPattern recognitionComputer Science ApplicationsHuman-Computer Interactiondata-driven modelingData models Semantics Probability distribution Matrix decomposition Computational modeling Probabilistic logicLSASingular value decompositionComputer Science (miscellaneous)Probability distributionTruncation (statistics)Artificial intelligenceHellinger distancebusinessAlgorithmInformation SystemsIEEE Transactions on Emerging Topics in Computing
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Composite laminates buckling optimization through Levy based Ant Colony Optimization

2010

In this paper, the authors propose the use of the Levy probability distribution as leading mechanism for solutions differentiation in an efficient and bio-inspired optimization algorithm, ant colony optimization in continuous domains, ACOR. In the classical ACOR, new solutions are constructed starting from one solution, selected from an archive, where Gaussian distribution is used for parameter diversification. In the proposed approach, the Levy probability distributions are properly introduced in the solution construction step, in order to couple the ACOR algorithm with the exploration properties of the Levy distribution. The proposed approach has been tested on mathematical test functions…

Settore ING-INF/05 - Sistemi Di Elaborazione Delle InformazioniMathematical optimizationComputer scienceGaussianAnt colony optimization algorithmsLévy distributionMaximizationFunction (mathematics)Composite laminatessymbols.namesakeDistribution (mathematics)symbolsProbability distributionSettore ICAR/08 - Scienza Delle CostruzioniLevy probability distribution Ant colony optimization composite laminates buckling load maximization
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Poisson Regression with Change-Point Prior in the Modelling of Disease Risk around a Point Source

2003

Bayesian estimation of the risk of a disease around a known point source of exposure is considered. The minimal requirements for data are that cases and populations at risk are known for a fixed set of concentric annuli around the point source, and each annulus has a uniquely defined distance from the source. The conventional Poisson likelihood is assumed for the counts of disease cases in each annular zone with zone-specific relative risk and parameters and, conditional on the risks, the counts are considered to be independent. The prior for the relative risk parameters is assumed to be piecewise constant at the distance having a known number of components. This prior is the well-known cha…

Statistics and ProbabilityBayes estimatorPoint sourcePosterior probabilityGeneral MedicineConditional probability distributionPoisson distributionsymbols.namesakePrior probabilityStatisticssymbolsPoisson regressionStatistics Probability and UncertaintyGibbs samplingMathematicsBiometrical Journal
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Response models for mixed binary and quantitative variables

1992

SUMMARY A number of special representations are considered for the joint distribution of qualitative, mostly binary, and quantitative variables. In addition to the conditional Gaussian models and to conditional Gaussian regression chain models some emphasis is placed on models derived from an underlying multivariate normal distribution and on models in which discrete probabilities are specified linearly in terms of unknown parameters. The possibilities for choosing between the models empirically are examined, as well as the testing of independence and conditional independence and the estimation of parameters. Often the testing of independence is exactly or nearly the same for a number of di…

Statistics and ProbabilityChain rule (probability)Applied MathematicsGeneral MathematicsMultivariate normal distributionConditional probability distributionAgricultural and Biological Sciences (miscellaneous)Discriminative modelConditional independenceJoint probability distributionStatisticsStatistics Probability and UncertaintyGeneral Agricultural and Biological SciencesConditional varianceIndependence (probability theory)MathematicsBiometrika
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A Unified Approach to Likelihood Inference on Stochastic Orderings in a Nonparametric Context

1998

Abstract For data in a two-way contingency table with ordered margins, we consider various hypotheses of stochastic orders among the conditional distributions considered by rows and show that each is equivalent to requiring that an invertible transformation of the vectors of conditional row probabilities satisfies an appropriate set of linear inequalities. This leads to the construction of a general algorithm for maximum likelihood estimation under multinomial sampling and provides a simple framework for deriving the asymptotic distribution of log-likelihood ratio tests. The usual stochastic ordering and the so called uniform and likelihood ratio orderings are considered as special cases. I…

Statistics and ProbabilityCombinatoricsIndependent and identically distributed random variablesLinear inequalityTransformation (function)Likelihood-ratio testAsymptotic distributionApplied mathematicsConditional probability distributionStatistics Probability and UncertaintyStochastic orderingStatistical hypothesis testingMathematicsJournal of the American Statistical Association
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