Relevant bibliographies by topics / NonGaussianità

Contents

  1. Journal articles
  2. Dissertations / Theses
  3. Book chapters
  4. Conference papers

Academic literature on the topic 'NonGaussianità'

Author: Grafiati
Published: 4 June 2021
Last updated: 16 February 2022

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'NonGaussianità.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Journal articles on the topic "NonGaussianità"

1

Lehners, Jean-Luc. "Ekpyrotic Nongaussianity: A Review." Advances in Astronomy 2010 (2010): 1–19. http://dx.doi.org/10.1155/2010/903907.

Full text
Abstract:
Ekpyrotic models and their cyclic extensions solve the standard cosmological flatness, horizon, and homogeneity puzzles by postulating a slowly contracting phase of the universe prior to the big bang. This ekpyrotic phase also manages to produce a nearly scale-invariant spectrum of scalar density fluctuations but, crucially, with significant nongaussian corrections. In fact, some versions of ekpyrosis are on the borderline of being ruled out by observations, while, interestingly, the best-motivated models predict levels of nongaussianity that will be measurable by near-future experiments. Here, we review these predictions in detail, and comment on their implications.
APA, Harvard, Vancouver, ISO, and other styles
2

Bramante, Joseph. "Generically large nongaussianity in small multifield inflation." Journal of Cosmology and Astroparticle Physics 2015, no. 07 (July 7, 2015): 006. http://dx.doi.org/10.1088/1475-7516/2015/07/006.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Barnaby, Neil, Ryo Namba, and Marco Peloso. "Phenomenology of a pseudo-scalar inflaton: naturally large nongaussianity." Journal of Cosmology and Astroparticle Physics 2011, no. 04 (April 7, 2011): 009. http://dx.doi.org/10.1088/1475-7516/2011/04/009.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Huang, Yufen, Ching-Ren Cheng, and Tai-Ho Wang. "Pair-perturbation influence functions of nongaussianity by projection pursuit." Computational Statistics & Data Analysis 52, no. 8 (April 2008): 3971–87. http://dx.doi.org/10.1016/j.csda.2008.01.009.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Yang, Z., A. T. Walden, and E. J. McCoy. "Correntropy: Implications of nonGaussianity for the moment expansion and deconvolution." Signal Processing 91, no. 4 (April 2011): 864–76. http://dx.doi.org/10.1016/j.sigpro.2010.09.004.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Yin, Hujun, and Israr Hussain. "Independent component analysis and nongaussianity for blind image deconvolution and deblurring." Integrated Computer-Aided Engineering 15, no. 3 (May 12, 2008): 219–28. http://dx.doi.org/10.3233/ica-2008-15302.

Full text
APA, Harvard, Vancouver, ISO, and other styles
7

ALLEGRA, MICHELE, PAOLO GIORDA, and MATTEO G. A. PARIS. "DECOHERENCE OF GAUSSIAN AND NONGAUSSIAN PHOTON-NUMBER ENTANGLED STATES IN A NOISY CHANNEL." International Journal of Quantum Information 09, supp01 (January 2011): 27–38. http://dx.doi.org/10.1142/s0219749911007009.

Full text
Abstract:
We consider photon-number entangled states (PNES) and study the degradation of their entanglement in a noisy channel, using different separability criteria and a recently proposed measure of nonGaussianity as key tools. Upon comparing Gaussian and nonGaussian states within the class, we collect some evidence that Gaussian states are maximally robust against noise, i.e. the complete loss of entanglement occurs in maximal time. However, the gap with respect to nonGaussian states is negligible for sufficiently high energy of the states.
APA, Harvard, Vancouver, ISO, and other styles
8

Hyvärinen, Aapo. "Complexity Pursuit: Separating Interesting Components from Time Series." Neural Computation 13, no. 4 (April 1, 2001): 883–98. http://dx.doi.org/10.1162/089976601300014394.

Full text
Abstract:
A generalization of projection pursuit for time series, that is, signals with time structure, is introduced. The goal is to find projections of time series that have interesting structure, defined using criteria related to Kolmogoroff complexity or coding length. Interesting signals are those that can be coded with a short code length. We derive a simple approximation of coding length that takes into account both the nongaussianity and the autocorrelations of the time series. Also, we derive a simple algorithm for its approximative optimization. The resulting method is closely related to blind separation of nongaussian, time-dependent source signals.
APA, Harvard, Vancouver, ISO, and other styles
9

Abramo, L. Raul, and Thiago S. Pereira. "Testing Gaussianity, Homogeneity, and Isotropy with the Cosmic Microwave Background." Advances in Astronomy 2010 (2010): 1–25. http://dx.doi.org/10.1155/2010/378203.

Full text
Abstract:
We review the basic hypotheses which motivate the statistical framework used to analyze the cosmic microwave background, and how that framework can be enlarged as we relax those hypotheses. In particular, we try to separate as much as possible the questions of gaussianity, homogeneity, and isotropy from each other. We focus both on isotropic estimators of nongaussianity as well as statistically anisotropic estimators of gaussianity, giving particular emphasis on their signatures and the enhanced “cosmic variances” that become increasingly important as our putative Universe becomes less symmetric. After reviewing the formalism behind some simple model-independent tests, we discuss how these tests can be applied to CMB data when searching for large-scale “anomalies”.
APA, Harvard, Vancouver, ISO, and other styles
10

Hurri, Jarmo, and Aapo Hyvärinen. "Simple-Cell-Like Receptive Fields Maximize Temporal Coherence in Natural Video." Neural Computation 15, no. 3 (March 1, 2003): 663–91. http://dx.doi.org/10.1162/089976603321192121.

Full text
Abstract:
Recently, statistical models of natural images have shown the emergence of several properties of the visual cortex. Most models have considered the nongaussian properties of static image patches, leading to sparse coding or independent component analysis. Here we consider the basic time dependencies of image sequences instead of their nongaussianity. We show that simple-cell-type receptive fields emerge when temporal response strength correlation is maximized for natural image sequences. Thus, temporal response strength correlation, which is a nonlinear measure of temporal coherence, provides an alternative to sparseness in modeling simple-cell receptive field properties. Our results also suggest an interpretation of simple cells in terms of invariant coding principles, which have previously been used to explain complex-cell receptive fields.
APA, Harvard, Vancouver, ISO, and other styles
More sources

Dissertations / Theses on the topic "NonGaussianità"

1

Albarelli, Francesco. "Nonlinearity as a resource for nonclassicality." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/8300/.

Full text
Abstract:
Lo scopo di questo lavoro è cercare un'evidenza quantitativa a supporto dell'idea idea che la nonlinearità sia una risorsa per generare nonclassicità. Ci si concentrerà su sistemi unidimensionali bosonici, cercando soprattutto di connettere la nonlinearità di un oscillatore anarmonico, definito dalla forma del suo potenziale, alla nonclassicità del relativo ground state. Tra le numerose misure di nonclassicità esistenti, verranno impiegate il volume della parte negativa della funzione di Wigner e l'entanglement potential, ovvero la misura dell'entanglement prodotto dallo stato dopo il passaggio attraverso un beam splitter bilanciato avente come altro stato in ingresso il vuoto. La nonlinearità di un potenziale verrà invece caratterizzata studiando alcune proprietà del suo ground state, in particolare se ne misurerà la non-Gaussianità e la distanza di Bures rispetto al ground state di un oscillatore armonico di riferimento. Come principale misura di non-Gaussianità verrà utilizzata l'entropia relativa fra lo stato e il corrispettivo stato di riferimento Gaussiano, avente la medesima matrice di covarianza. Il primo caso che considereremo sarà quello di un potenziale armonico con due termini polinomiali aggiuntivi e il ground state ottenuto con la teoria perturbativa. Si analizzeranno poi alcuni potenziali il cui ground state è ottenibile analiticamente: l'oscillatore armonico modificato, il potenziale di Morse e il potenziale di Posch-Teller. Si andrà infine a studiare l'effetto della nonlinearità in un contesto dinamico, considerando l'evoluzione unitaria di uno stato in ingresso in un mezzo che presenta una nonlinearità di tipo Kerr. Nell'insieme, i risultati ottenuti con tutti i potenziali analizzati forniscono una forte evidenza quantitativa a supporto dell'idea iniziale. Anche i risultati del caso dinamico, dove la nonlinearità costituisce una risorsa utile per generare nonclassicità solo se lo stato iniziale è classico, confermano la pittura complessiva. Si sono inoltre studiate in dettaglio le differenze nel comportamento delle due misure di nonclassicità.
APA, Harvard, Vancouver, ISO, and other styles
2

Galliano, Dominic. "Searching for isocurvature non-Gaussianity in the CMB trispectrum." Thesis, University of Portsmouth, 2014. https://researchportal.port.ac.uk/portal/en/theses/searching-for-isocurvature-nongaussianity-in-the-cmb-trispectrum(22a58c55-fd97-46eb-bd65-2d7421460f9e).html.

Full text
Abstract:
Inflation was introduced to the Big Bang model of the universe as a method to solve the problems associated with this model. It also gave an explanation for the small scale inhomogeneities observed in the universe today. Since the concept was introduced, more complex models inflation have been postulated as time has gone on. However the amount of information available to measure the feasability of all these models has not grown at the same rate. Very high precision measurements are now making it possible to start getting significant measurements of parameters measuring how non-Gaussian the distributions of perturbations from the inflation models are. These measurements have mostly been done using third order statistics,i.e. the bispectrum. The work presented in this looks at how good a measurement Planck will be able to make of non-Gaussian parameters using fourth-order statistics, i.e. the trispectrum. In particular this work looks at models which have a second mode in addition to the standard adiabatic mode of the curvature perturbation, the isocurvature mode. These modes can be generated by models where there is more than one field present during inflation. Both these modes could be non-Gaussian, which gives rise to 17 parameters that can measure non-Gaussianity using the trispectrum. The aim of this work is to determine how good a measurement Planck could make of these parameters, especially considering they are not independent of each other. This work is presented in the context of determing bounds for model parameters for different inflation models.
APA, Harvard, Vancouver, ISO, and other styles
3

Tellarini, Matteo. "Primordial non-Gaussianity in the large-scale structure of the Universe." Thesis, University of Portsmouth, 2016. https://researchportal.port.ac.uk/portal/en/theses/primordial-nongaussianity-in-the-largescale-structure-of-the-universe(dd11bbd3-33e9-471f-8713-1efd4b6a6dbb).html.

Full text
Abstract:
Primordial fluctuations are expected to be produced in the very early Universe, sourcing the anisotropies in the cosmic microwave background and seeding the formation of structures. In this thesis we study the effect of density perturbations produced during inflation on the large-scale galaxy bispectrum. We start by reviewing the basic concepts of modern cosmology and introducing the tools used in this research: Newtonian perturbation theory, statistics of random fields, the mass function of collapsed halos and the halo bias model. We then briefly describe how models of inflation source local-type non-Gaussian distributed primordial density perturbations. We apply these tools to justify the bivariate model for the halo density in the presence of primordial non-Gaussianity and derive some known results, like the scale-dependent halo bias. The aim is to show that the statistics of large-scale structure can be used to probe local-type non-Gaussianity of the primordial density field, complementary to existing constraints from the cosmic microwave background. Parametrising the amount of primordial non-Gaussianity with the leading-order non-linear parameter fNL and the next-order one, gNL, we will investigate how galaxy and matter bispectra can distinguish between them, despite their effects being nearly degenerate in the power spectra. We determine a connection between the sign of the halo bispectrum on large scales and the parameter gNL and construct a combination of halo and matter bispectra that is sensitive to fNL. After that, we will focus on local-type non-Gaussianity with fNL only. It is known that the non-linear evolution of the matter density introduces a non-local tidal term in the halo bias model. Furthermore, we will show that the bivariate model in the Lagrangian frame leads to a novel non-local convective term in the Eulerian frame which can lead to non-negligible corrections in the halo bispectra, in particular on large scales or at high redshift. Finally, we address the problem of modelling redshift space distortions in the galaxy bispectrum, finding novel contributions with the characteristic large scale amplification induced by local-type non-Gaussianity. Therefore, redshift space distortions can potentially lead to a biased measurement of fNL, if not properly accounted for. Moreover, we propose an analytic template for the monopole which can be used to t against data on large scales, extending models used in recent measurements. We conclude the thesis with some discussion of future developments. Observational constraints will also be discussed, based on idealised forecasts onfNL { the accuracy of the determination of fNL. Our findings suggest that the constraining power of the galaxy bispectrum in current surveys would provide fNL measurements competitive with constraints from the cosmic microwave background and future surveys could improve this further.
APA, Harvard, Vancouver, ISO, and other styles
4

Kalus, Benedict Konrad Wilhelm. "The distribution of galaxies as a test of primordial non-Gaussianity." Thesis, University of Portsmouth, 2018. https://researchportal.port.ac.uk/portal/en/theses/the-distribution-of-galaxies-as-a-test-of-primordial-nongaussianity(e07ef8fd-9509-4992-91fc-9c69465effec).html.

Full text
Abstract:
Cosmic inflation is a paradigm that successfully seeds large scale structure in a big bang cosmology whilst causing the Universe to be statistically isotropic. Inflation occurred at energy scales that are too high to be accessible with accelerator experiments, thus we have to rely entirely on cosmological observations to rule out classes of inflationary models and get insight into the physics of the early Universe. One way to distinguish these models is by measuring how close their predicted primordial fluctuations are to being Gaussian distributed, described at first order by the parameter fNL. Local primordial non-Gaussianity alters the biasing law between dark- matter halos and the underlying massdensity field at the largest scales [1,2]. Currently, the tightest constraints on the local fNL = 0.8±5.0 come from the cosmic microwave background experiment Planck [3]. Next generation ground-based experiments will be limited by cosmic variance, and we need a different approach to independently confirm these results, and to further narrow down our constraints on the inflationary epoch. Galaxy clustering studies so far could not compete with the precision of the fNL results from the microwave background, but upcoming galaxy surveys will come close to independently confirm the Planck results. Combining future galaxy clustering and Cosmic Microwave Background data will improve fNL constraints such that they will provide physically interesting results. This will only be possible if some challenges can be addressed properly, of which two are addressed in this thesis. The first problem is that fNL measurements take place at the very largest scales, which are close to maximum scale fitting into the survey volume. This means that we have to rely on a low number of modes and we therefore cannot assume the likelihood of our power spectrum measurement to be Gaussian. The Inverse Cubic Normal distribution is a very good approximation to what we expect for the true likelihood of the Power Spectrum assuming an almost Gaussian galaxy density field. On top of that, it has the advantage of absorbing the model dependence of the Power Spectrum covariance matrix into the functional form of the posterior distribution function. Thus, one does not have to run simulations to estimate the covariance matrix for each model to be tested [4]. The other problem addressed in this thesis is that galaxy surveys are plagued by systematic contaminants, especially the effect of foreground stars, at the scales interesting for fNL measurements. I discuss two contaminant mitigation techniques, mode deprojection and mode subtraction. Mode deprojection needs a covariance based estimator for the Power Spectrum, such as the Quadratic Maximum Likelihood estimator. This however, is computationally infeasible for a 3-dimensional clustering analysis. Applying mode subtraction na ̈ıvely using the simpler Feldman-Kaiser-Peacock Power Spectrum estimator leads to a biased measurement. I introduce an additional factor that unbiases this estimate and show that mode deprojection and subtraction are then in fact identical. This allows a fast error mitigation and Power Spectrum estimation trading against a small amount of information loss [5]. This technique is tested using the twelfth data release of the Baryon Acoustic Oscillation Survey. Previously, even after accounting for the stellar contamination, the power spectrum of an fNL analysis using data of the ninth data release of the Baryon Oscillation Spectroscopic Survey [6] did not agree well with the model for any value fNL. Interestingly, even using the new methods, and performing a more careful analysis, the resulting Power Spectrum agrees with the Power Spectrum obtained by applying the methods of [6]. This means that there is still some unexplained discrepancy between our measurement and our model. I therefore discuss other sources of systematic data contamination.
APA, Harvard, Vancouver, ISO, and other styles
5

Cheng, Chin-Zen, and 鄭清仁. "Influence Analysis of Nongaussianity by Applying Projection Pursuit." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/53766687957568781608.

Full text
Abstract:
碩士
國立中正大學
統計科學所
94
Gaussian distribution is the least structured from the information-theoretic point of view. In this thesis, the projection pursuit is performed by finding the most nongaussian projection to explore the clustering structure of the data. We use kurtosis as a measure of nongaussianity to find the projection direction. Kurtosis is well known to be sensitive to abnormal observations, henceforth the projection direction will be essentially affected by unusual points. The perturbation theory provides a useful tool in sensitivity analysis. In this thesis, we develop influence functions for the projection direction to investigate the influence of unusual observations. It is well-known that single-perturbation diagnostics can suffer from the masking effect. Hence we also develop the pair-perturbation influence functions to detect the masked influential points and outliers. A simulated data and a specific data example are provided to illustrate the applications of these approaches.
APA, Harvard, Vancouver, ISO, and other styles

Book chapters on the topic "NonGaussianità"

1

Wang, Gang, Xin Xu, and Dewen Hu. "Local Stability Analysis of Maximum Nongaussianity Estimation in Independent Component Analysis." In Advances in Neural Networks - ISNN 2006, 1133–39. Berlin, Heidelberg: Springer Berlin Heidelberg, 2006. http://dx.doi.org/10.1007/11759966_167.

Full text
APA, Harvard, Vancouver, ISO, and other styles

Conference papers on the topic "NonGaussianità"

1

Liu, Keying, and Rui Li. "Source Extraction Using Novel NonGaussianity Measure." In 2010 International Conference on Intelligent Computing and Cognitive Informatics (ICICCI). IEEE, 2010. http://dx.doi.org/10.1109/icicci.2010.78.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Zhao Liquan and Jia Yanfei. "Harmonic and interharmonic estimation using improved complex maximization of nongaussianity algorithm." In 2010 2nd International Conference on Computer Engineering and Technology. IEEE, 2010. http://dx.doi.org/10.1109/iccet.2010.5486310.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Novey, M., and T. Adali. "Adaptable Nonlinearity for Complex Maximization of Nongaussianity and a Fixed-Point Algorithm." In 2006 IEEE Signal Processing Society Workshop. IEEE, 2006. http://dx.doi.org/10.1109/mlsp.2006.275526.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Gorecka, Joanna. "Noncerebral waves detection from frontal brain electrical activity using the quantitative measure of nongaussianity." In 2014 19th International Conference on Methods & Models in Automation & Robotics (MMAR). IEEE, 2014. http://dx.doi.org/10.1109/mmar.2014.6957446.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Chen, Mo, Temujin Gautama, Dragan Obradovic, Jonathon Chambers, and Danilo Mandic. "Exploiting Signal Nongaussianity and Nonlinearity for Performance Assessment of Adaptive Filtering Algorithms: Qualitative Performance of Kalman Filter." In 2006 IEEE Nonlinear Statistical Signal Processing Workshop. IEEE, 2006. http://dx.doi.org/10.1109/nsspw.2006.4378837.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Ghavami, Siavash, and Bahman Abolhassani. "Detection of DS-SS Signals over Fading Channels without Prior Knowledge of Spreading Sequence by Measuring Signal Nongaussianity." In 2006 IEEE 17th International Symposium on Personal, Indoor and Mobile Radio Communications. IEEE, 2006. http://dx.doi.org/10.1109/pimrc.2006.254353.

Full text
APA, Harvard, Vancouver, ISO, and other styles
You might also be interested in the extended bibliographies on the topic 'NonGaussianità' for particular source types:
Journal articles
We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!

To the bibliography