Search results for "Statistical"

showing 10 items of 4960 documents

CFD Predictions of Sufficient Suspension Conditions in Solid-Liquid Agitated Tanks

2012

Abstract Most research efforts on mechanically agitated solid-liquid contactors have been devoted to the assessment of the minimum impeller speed for complete off-bottom suspension, N js . Actually, many industrial vessels are operated at impeller speeds slightly lower than N js (Oldshue, 1983; Rieger et al., 1988). This suggests that the sufficient suspension condition, which is quantitatively specified in this paper by introducing a suitably defined quantity N ss , may represent a valid alternative to that of complete suspension. In the present work time-dependent RANS simulations were carried out with the aim of predicting the achievement of sufficient suspension conditions. The Eulerian…

Settore ING-IND/26 - Teoria Dello Sviluppo Dei Processi Chimicistirred tank Computational Fluid Dynamics (CFD) solid-liquid suspension complete suspension Unsuspended Solid Criterion (USC) sufficient suspensionMaterials sciencebusiness.industrySettore ING-IND/25 - Impianti ChimiciApplied MathematicsComputational MechanicsGeneral Physics and AstronomyStatistical and Nonlinear PhysicsComputational fluid dynamicsChemical engineeringMechanics of MaterialsModeling and SimulationSettore ING-IND/06 - FluidodinamicabusinessSuspension (vehicle)Engineering (miscellaneous)Solid liquidInternational Journal of Nonlinear Sciences and Numerical Simulation
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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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METABOLIC NETWORKS ROBUSTNESS: THEORY, SIMULATIONS AND RESULTS

2011

Metabolic networks are composed of several functional modules, reproducing metabolic pathways and describing the entire cellular metabolism of an organism. In the last decade, an enormous interest has grown for the study of tolerance to errors and attacks in metabolic networks. Studies on their robustness have suggested that metabolic networks are tolerant to errors, but very vulnerable to targeted attacks against highly connected nodes. However, many findings on metabolic networks suggest that the above classification is too simple and imprecise, since hub node attacks can be by-passed if alternative metabolic paths can be exploited. On the contrary, non-hub nodes attacks can affect cell …

Settore ING-INF/05 - Sistemi Di Elaborazione Delle InformazioniCellular metabolismTheoretical computer scienceComputer Networks and Communicationsnetwork robustness and fault tolerance propertietopological analysiRobustness (evolution)Metabolic networkComputational biologyfunctional analysisComputingMethodologies_PATTERNRECOGNITIONstatistical analysiStatistical analysisOrganismMathematics
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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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A Conceptual Probabilistic Model for the Induction of Image Semantics

2010

In this paper we propose a model based on a conceptual space automatically induced from data. The model is inspired to a well-founded robotics cognitive architecture which is organized in three computational areas: sub-conceptual, linguistic and conceptual. Images are objects in the sub-conceptual area, that become "knoxels" into the conceptual area. The application of the framework grants the automatic emerging of image semantics into the linguistic area. The core of the model is a conceptual space induced automatically from a set of annotated images that exploits and mixes different information concerning the set of images. Multiple low level features are extracted to represent images and…

Settore ING-INF/05 - Sistemi Di Elaborazione Delle InformazioniImage ClassificationComputer sciencebusiness.industryFeature extractionimage semantics conceptual spaceConceptual model (computer science)Statistical modelcomputer.software_genreConceptual schemaVisualizationSet (abstract data type)Data setAutomatic image annotationLatent Semantic AnalysisArtificial intelligencebusinesscomputerNatural language processing
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Introducing Pseudo-Singularity Points for Efficient Fingerprints Classification and Recognition

2010

Fingerprint classification and matching are two key issues in automatic fingerprint recognition. Generally, fingerprint recognition is based on a set of relevant local characteristics, such as ridge ending and bifurcation (minutiae). Fingerprint classification is based on fingerprint global features, such as core and delta singularity points. Unfortunately, singularity points are not always present in a fingerprint image: the acquisition process is not ideal, so that the fingerprint is broken, or the fingerprint belongs to the arch class. In the above cases, pseudo-singularity-points will be detected and extracted to make possible fingerprint classification and matching. As result, fingerpr…

Settore ING-INF/05 - Sistemi Di Elaborazione Delle InformazioniMinutiaeContextual image classificationbusiness.industryComputer scienceData_MISCELLANEOUSFeature extractionFingerprint Verification CompetitionPattern recognitionFingerprint recognitionFingerprint singularity regions classification matching algorithm core and delta points fingerprint recognition systems.Statistical classificationFingerprintData_GENERALComputer visionArtificial intelligencebusinessBlossom algorithm2010 International Conference on Complex, Intelligent and Software Intensive Systems
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Real-Time Object Detection in Embedded Video Surveillance Systems

2008

In this paper we report a new method to detect both moving objects and new stationary objects in video sequences. On the basis of temporal consideration we classify pixels into three classes: background, midground and foreground to distinguish between long-term, medium-term and short-term changes. The algorithm has been implemented on a hardware platform with limited resources and it could be used in a wider system like a wireless sensor networks. Particular care has been put in realizing the algorithm so that the limited available resources are used in an efficient way. Experiments have been conducted on publicly available datasets and performance measures are reported.

Settore ING-INF/05 - Sistemi Di Elaborazione Delle InformazioniPixelBasis (linear algebra)business.industryComputer scienceReal-time computingVideo sequencevideo surveillance embedded systemsObject detectionTerm (time)Statistical classificationComputer visionArtificial intelligencebusinessWireless sensor networkLimited resources2008 Ninth International Workshop on Image Analysis for Multimedia Interactive Services
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Retinal image synthesis through the least action principle

2020

Eye fundus image analysis is a fundamental approach in medical diagnosis and follow-up ophthalmic diagnostics. Manual annotation by experts needs hard work, thus only a small set of annotated vessel structures is available. Examples such as DRIVE and STARE include small sets for training images of fundus image benchmarks. Moreover, there is no vessel structure annotation for a number of fundus image datasets. Synthetic images have been generated by using appropriate parameters for the modeling of vascular networks or by methods developing deep learning techniques and supported by performance hardware. Our methodology aims to produce high-resolution synthetic fundus images alternative to the…

Settore ING-INF/05 - Sistemi Di Elaborazione Delle InformazioniSettore INF/01 - Informaticapredictive evaluation diseasesComputer sciencebusiness.industryDeep learningComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISIONFundus (eye)Real imageSmall setPrinciple of least actionImage (mathematics)fundus image analysisAnnotationComputer visionArtificial intelligenceMedical diagnosisbusinessstatistical featuressynthetic retinal imagedata augmentation2020 5th International Conference on Intelligent Informatics and Biomedical Sciences (ICIIBMS)
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Lactate level and handgrip test in migraine and fibromyalgia after self-myofascial release treatment

2019

The Aim of the study was to determine the effect of self-myofascial release (SMFR) treatment on handgrip test score in patients with fibromyalgia and migraine, investigating also if the lactate levels influenced the result. Twenty-five subjects affected by migraine (age 49.7±12.5; height 164.9±6.62 cm; weight 68.6±16.9 kg) and ten subjects affected by fibromyalgia (age 43.7±21.2; height 158±5.65 cm; weight 70±28.9 kg) were enrolled in the study. The assessments included a handgrip test, in order to evaluate isometric strength of both hands and forearm muscles and the lactate levels evaluation. The treatment was performed in the three most painful trigger points indicated from subjects as to…

Settore M-EDF/02 - Metodi E Didattiche Delle Attivita' Sportivebusiness.industryMyofascial Release TreatmentDisabling disorderRelaxing muscle techniqueIsometric exerciseIsometric contractionmedicine.diseaseTest (assessment)medicine.anatomical_structureMigraineForearmRelaxing muscle technique.Settore BIO/10 - BiochimicaFibromyalgiaAnesthesiaStatistical significanceEducación Física y DeportivaMedicineSettore MED/26 - NeurologiaIn patientbusinessJournal of Human Sport and Exercise - 2019 - Summer Conferences of Sports Science
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A Psychometric Evaluation of the Group Environment Questionnaire in a Sample of Professional Basketball and Soccer Players

2013

Psychometric properties of the Group environment Questionnaire were investigated in a large sample of soccer (n = 222) and professional basketball players (n = 375). Confirmatory factor analysis was performed both on the total sample and on the two sub samples through a multi-group approach; associations between cohesion and the duration of belonging to the team were also explored. Results confirmed the four-factor structure proposed by Carron's original model even though some items with low loadings were eliminated. No signifcant associations were found between team cohesion and the duration of belonging to the team. © Perceptual & Motor Skills 2013.

Settore M-PSI/01 - Psicologia GeneraleAdultMaleBasketballTime FactorsAdolescentPsychometricseducationExperimental and Cognitive PsychologySample (statistics)BasketballYoung AdultSurveys and QuestionnairesSoccerHumansSensory SystemsConfirmatory factor analysisGroup cohesion psychometrics sport psychologyLarge sampleGroup ProcessesCohesion (linguistics)AthletesCohesion Group Environment Questionnaire Basket SoccerPsychologyFactor Analysis StatisticalSocial psychologyClinical psychology
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