Analysis of irregular behaviour on an optical computing logic cell

A new methodology to study irregular behaviours in logic cells is reported. It is based on two types of diagrams, namely phase and working diagrams. Sets of four bits are grouped and represented by their hexadecimal equivalent. Some hexadecimal numbers correspond to certain logic functions. The influence of the internal and external tolerances, namely those appearing in the employed devices and in the working signals, may be analysed with this method. Its importance in the case of logic structures with chaotic behaviours is studied

On the void explanation of the Cold Spot

The integrated Sachs-Wolfe (ISW) contribution induced on the cosmic microwave background by the presence of a supervoid as the one detected by Szapudi et al. (2015) is reviewed in this letter in order to check whether it could explain the Cold Spot (CS) anomaly. Two different models, previously used for the same purpose, are considered to describe the matter density profile of the void: a top hat function and a compensated profile produced by a Gaussian potential. The analysis shows that, even enabling ellipticity changes or different values for the dark-energy equation of state parameter $\omega$, the ISW contribution due to the presence of the void does not reproduce the properties of the CS. Finally, the probability of alignment between the void and the CS is also questioned as an argument in favor of a physical connection between these two phenomena

Exploring two-spin internal linear combinations for the recovery of the CMB polarization

We present a methodology to recover cosmic microwave background (CMB) polarization in which the quantity $P = Q+ iU$ is linearly combined at different frequencies using complex coefficients. This is the most general linear combination of the $Q$ and $U$ Stokes parameters which preserves the physical coherence of the residual contribution on the CMB estimation. The approach is applied to the internal linear combination (ILC) and the internal template fitting (ITF) methodologies. The variance of $P$ of the resulting map is minimized to compute the coefficients of the linear combination. One of the key aspects of this procedure is that it serves to account for a global frequency-dependent shift of the polarization phase. Although in the standard case, in which no global E-B transference depending on frequency is expected in the foreground components, minimizing $\left\langle |P|^2\right\rangle$ is similar to minimizing $\left\langle Q^2\right\rangle$ and $\left\langle U^2\right\rangle$ separately (as previous methodologies proceed), multiplying $Q$ and $U$ by different coefficients induces arbitrary changes in the polarization angle and it does not preserve the coherence between the spinorial components. The approach is tested on simulations, obtaining a similar residual level with respect to the one obtained with other implementations of the ILC, and perceiving the polarization rotation of a toy model with the frequency dependence of the Faraday rotation.Comment: 14 pages, 8 figures, 2 tables. Accepted for publication in MNRA

THE SANSEVERO CHAPEL, A THREE-DIMENSIONAL POINT OF VIEW

Abstract. In this article, the importance of the three-dimensional survey in architectural spaces will be studied, taking special relevance in the study of the perception of perspective, since three-dimensional space would not be understood from a two-dimensional representation of space. The project aims to develop a comparison between the representation systems based on the automatic acquisition of various data by different 3D survey techniques. In particular, the document reports the results of an analysis based on the Sansevero Chapel in Naples.</p

Radial derivatives as a test of pre-Big-Bang events on the Planck data

Although the search for azimutal patterns in cosmological surveys is useful to characterise some effects depending exclusively on an angular distance within the standard model, they are considered as a key distinguishing feature of some exotic scenarios, such as bubble collisions or conformal cyclic cosmology (CCC). In particular, the CCC is a non-stardard framework which predicts circular patterns on the CMB intensity fluctuations. Motivated by some previous works which explore the presence of radial gradients, we apply a methodology based on the radial derivatives to the latest release of \textit{Planck} data. The new approach allows exhaustive studies to be performed at all sky directions at a HEALPix resolution of $N_{\mathrm{side}} = 1024$. Specifically, two different analyses are performed focusing on weight functions in both small (up to a $5$-degree radius) and large scales. We present a comparison between our results and those shown by An et al. (2017), and An et al. (2018). In addition, a possible polarization counterpart of these circular patterns is also analysed for the most promising case. Taking into account the limitations to characterize the significance of the results, including the possibility of suffering a look-elsewhere effect, no strong evidence of the kind of circular patterns expected from CCC is found in the \textit{Planck} data for either the small or the large scales.Comment: 8 figures, 4 table

Bayesian inference methodology for Primordial Power Spectrum reconstructions from Large Scale Structure

We use Bayesian inference and nested sampling to develop a non-parametric method to reconstruct the primordial power spectrum $P_{\mathcal{R}}(k)$ from Large Scale Structure (LSS) data. The performance of the method is studied by applying it to simulations of the clustering of two different object catalogues, low-$z$ (ELGs) and high-$z$ (QSOs), and considering two different photometric errors. These object clusterings are derived from different templates of the primordial power spectrum motivated by models of inflation: the Standard Model power law characterized by the two parameters $A_s$ and $n_s$; a local feature template; and a global oscillatory template. Our reconstruction method involves sampling $N$ knots in the log $\{k,P_{\mathcal{R}}(k)\}$ plane. We use two statistical tests to examine the reconstructions for signs of primordial features: a global test comparing the evidences and a novel local test quantifying the power of the hypothesis test between the power law model and the marginalized probability over $N$ model. The method shows good performance in all scenarios considered. In particular, the tests show no feature detection for the SM. The method is able to detect power spectrum deviations at a level of $\approx 2\%$ for all considered features, combining either the low-$z$ or the high-$z$ redshift bins. Other scenarios with different redshift bins, photometric errors, feature amplitudes and detection levels are also discussed. In addition, we include a first application to real data from the Sloan Digital Sky Survey Luminous Red Galaxy Data Release 4 (SDSS LRG 04), finding no preference for deviations from the primordial power law. The method is flexible, model independent, and suitable for its application to existing and future LSS catalogues.Comment: 39 pages, 21 figures, submitted to JCA

Anotación morfosintáctica de la Web en portugués. Variedades nacionales, tipologías textuales y sistemas ortográficos

The great amount of text produced every day in the Web turned it as one of the main sources for obtaining linguistic corpora, that are further analyzed with Natural Language Processing techniques. On a global scale, languages such as Portuguese - official in 9 countries - appear on the Web in several varieties, with lexical, morphological and syntactic (among others) differences. Besides, a unified spelling system for Portuguese has been recently approved, and its implementation process has already started in some countries. However, it will last several years, so different varieties and spelling systems coexist. Since PoS-taggers for Portuguese are specifically built for a particular variety, this work analyzes different training corpora and lexica combinations aimed at building a model with high-precision annotation in several varieties and spelling systems of this language. Moreover, this paper presents different dictionaries of the new orthography (Spelling Agreement) as well as a new freely available testing corpus, containing different varieties and textual typologies.La gran cantidad de texto producido diariamente en la Web ha provocado que ésta sea utilizada como una de las principales fuentes para la obtención de corpus lingüísticos, posteriormente analizados utilizando técnicas de Procesamiento del Lenguaje Natural. En una escala global, idiomas como el portugués – oficial en 9 estados - aparecen en la Web en diferentes variedades, con diferencias léxicas, morfológicas y sintácticas, entre otras. A esto se suma la reciente aprobación de una ortografía unificada para las diferentes variedades del portugués, cuyo proceso de implementación ya ha comenzado en varios países, pero que se prolongará todavía durante varios años, conviviendo por lo tanto también diferentes ortografías. Una vez que los etiquetadores morfosintácticos existentes para el portugués están adaptados específicamente para una variedad nacional concreta, el presente trabajo analiza diferentes combinaciones de corpus de aprendizaje y de léxicos con el fin de obtener un modelo que mantenga una alta precisión de anotación en diferentes variedades y ortografías de esta lengua. Además, se presentan diferentes diccionarios adaptados a la nueva ortografía (Acordo Ortográfico de 1990) y un nuevo corpus de evaluación con diferentes variedades y tipologías textuales, disponibilizado libremente.This work has been supported by the HPCPLN project - Ref: EM13/041 (Galician Government) and by the Celtic - Ref: 2012-CE138 and Plastic - Ref: 2013-CE298 projects (Feder-Interconnecta)