548 research outputs found
Estudio e implementación de algoritmos de inferencia Bayesiana en sistemas espacio-temporales
Many problems in engineering require estimation of the state of a system which changes
over the time using a set of noisy measurements made on the system. In this project we
focus on the state-space approach to modelling dynamic systems. First of all we study the
Kalman filter algorithm which achieves the optimal solution in linear and Gaussian models.
The Kalman filter minimises the variance of the estimation error. In nonlinear and/or
Non-Gaussian models, approximations to the distribution of interest must be performed.
We study some suboptimal algorithms such as the Monte Carlo methods and in particular,
we focus on the Particle filter which is a Sequential Monte Carlo method. Over the project,
several experiments in MATLAB are done with the goal of discussing and comparing the
algorithms performances in several situations to demonstrate their theoretical features.Ingeniería de Sistemas Audiovisuale
ArchiTech: tool support for NFR-guided architectural decision-making
© 2012 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Researchers from requirements engineering and software architecture had emphasized the importance of NonFunctional Requirements and their influence in the architectural design process. To improve this process we have designed a tool, ArchiTech, which aims to support architects during the design process by suggesting alternative architectural decisions that can improve some types of non-functional requirements in a particular project, and facilitate the reuse of architectural knowledge shared between projects of the same architectural domain (e.g., web-based applications).Peer ReviewedPostprint (author’s final draft
Ceros y factorización de funciones holomorfas
El Teorema de factorización de Weierstrass generaliza el Teorema Fundamental del Álgebra a funciones enteras con finitos o infinitos ceros. En este trabajo veremos que cualquier función holomorfa se puede factorizar como un producto infinito de funciones holomorfas que involucran a los ceros de la función. Y también el recíproco, definiendo un producto infinito que cumpla una serie de condiciones, se puede definir una función holomorfa que tenga los ceros que queramos con las multiplicidades que queramos.Para ello vamos a estudiar propiedades de los productos infinitos, en concreto su convergencia.Nos apoyaremos en la Fórmula de Jensen y los Productos de Blashcke para estudiar la localización y distribución de ceros de funciones acotadas.Por último, veremos la aplicación de este estudio en las funciones Gamma de Euler y Zeta de Riemann. La función Gamma se puede definir como un producto infinito, aplicando Terorema de factorización de Weierstrass. En cuanto a la función Zeta, es evidente la importancia de la localizacion de sus ceros, ya que la Hipótesis de Riemann es uno de los problemas abiertos más importantes de la actualidad.<br /
Do Credit Supply Shocks Affect Employment in Middle-Income Countries?
This paper studies the extent to which increases in bank credit supply available for small and medium firms can foster formal employment in Mexico. We use a detailed dataset containing loan-level information for all loans extended by commercial banks to private firms in Mexico during the 2010-2016 period, when the economy was relatively stable. To obtain exogenous variation in credit supply, we exploit differences in the regional presence of Mexican banks across local labor markets by combining pre-existing market shares with national-level changes in banks’ credit supply, after accounting for local credit demand shocks. Then, we use employment registry data to compare changes in the number of formal workers registered by small and medium firms in local labor markets differently exposed to these shocks. We find that credit supply shocks have a large impact on formal employment: a positive credit shock of one standard deviation increases yearly employment growth by 0.45 percentage points (13 percent of the mean). Our results differ from the null to small effects identified by previous literature for developed countries, suggesting that credit supply shocks play a more prominent role for employment creation (and destruction) in low and middle-income countries.Centro de Estudios Distributivos, Laborales y Sociale
Automated analysis of feature models: Quo vadis?
Feature models have been used since the 90's to describe software product lines as a way of reusing common parts in a family of software systems. In 2010, a systematic literature review was published summarizing the advances and settling the basis of the area of Automated Analysis of Feature Models (AAFM). From then on, different studies have applied the AAFM in different domains. In this paper, we provide an overview of the evolution of this field since 2010 by performing a systematic mapping study considering 423 primary sources. We found six different variability facets where the AAFM is being applied that define the tendencies: product configuration and derivation; testing and evolution; reverse engineering; multi-model variability-analysis; variability modelling and variability-intensive systems. We also confirmed that there is a lack of industrial evidence in most of the cases. Finally, we present where and when the papers have been published and who are the authors and institutions that are contributing to the field. We observed that the maturity is proven by the increment in the number of journals published along the years as well as the diversity of conferences and workshops where papers are published. We also suggest some synergies with other areas such as cloud or mobile computing among others that can motivate further research in the future.Ministerio de Economía y Competitividad TIN2015-70560-RJunta de Andalucía TIC-186
Editorial
In fact, much of the attraction of network theory initially stemmed from the fact that many networks seem to exhibit some sort of universality, as most of them belong to one of three classes: random, scale-free and small-world networks. Structural properties have been shown to translate into different important properties of a given system, including efficiency, speed of information processing, vulnerability to various forms of stress, and robustness. For example, scale-free and random topologies were shown to be..
Ultrastrong waveguide QED with giant atoms
Quantum optics with giant emitters has shown a new route for the observation and manipulation of non-Markovian properties in waveguide QED. In this paper we extend the theory of giant atoms, hitherto restricted to the perturbative light-matter regime, to deal with the ultrastrong-coupling regime. Using static and dynamical polaron methods, we address the low-energy subspace of a giant atom coupled to an Ohmic waveguide beyond the standard rotating-wave approximation. We analyze the equilibrium properties of the system by computing the atomic frequency renormalization as a function of the coupling characterizing the localization-delocalization quantum phase transition for a giant atom. We show that virtual photons dressing the ground state are nonexponentially localized around the contact points but decay as a power law. The dynamics of an initially excited giant atom is studied, pointing out the effects of ultrastrong coupling on the Lamb shift and the spontaneous emission decay rate. Finally, we comment on the existence of the so-called oscillating bound states beyond the rotating-wave approximatio
Revisiting the Decomposition Process of Tetrahydrate Co(II) Acetate: A Sample’s Journey through Temperature.
Cobalt oxides, CoO and Co3O4, were obtained from Co (II) acetate tetrahydrate. The thermal decomposition pathway of the starting product was followed by combining thermogravimetric analysis and in situ X-ray thermodiffraction. Under a nitrogen atmosphere, cobalt monoxide with Zn-blende and rocksalt polymorphs could be obtained almost as single phases at 330 and 400 °C, respectively. In addition to these oxides, a Co (II) oxyacetate, Co3O(CH3COO)4, was stabilized as an intermediate phase. Under an air atmosphere, Co3O4 (spinel structure type) was obtained as the only final product. The involved phases in this thermal decomposition process were characterized with scanning and transmission electron microscopy (SEM and TEM, respectively).Depto. de Química InorgánicaFac. de Ciencias QuímicasTRUEpu
Constraint on the time variation of the fine-structure constant with the SDSS-III/BOSS DR12 quasar sample
From the Sloan Digital Sky Survey (SDSS) Data Release 12, which covers the
full Baryonic Oscillation Spectroscopic Survey (BOSS) footprint, we investigate
the possible variation of the fine-structure constant over cosmological
time-scales. We analyse the largest quasar sample considered so far in the
literature, which contains 13175 spectra (10363 from SDSS-III/BOSS DR12 + 2812
from SDSS-II DR7) with redshift 1. We apply the emission-line method on
the [O III] doublet (4960, 5008 A) and obtain for the relative variation of the fine-structure
constant. We also investigate the possible sources of systematics:
misidentification of the lines, sky OH lines, H and broad line
contamination, Gaussian and Voigt fitting profiles, optimal wavelength range
for the Gaussian fits, chosen polynomial order for the continuum spectrum,
signal-to-noise ratio and good quality of the fits. The uncertainty of the
measurement is dominated by the sky subtraction. The results presented in this
work, being systematics limited, have sufficient statistics to constrain
robustly the variation of the fine-structure constant in redshift bins ( 0.06) over the last 7.9 Gyr. In addition, we study the [Ne III]
doublet (3870, 3969 A) present in 462 quasar spectra and discuss the systematic
effects on using these emission lines to constrain the fine-structure constant
variation. Better constraints on (10) using
the emission-line method would be possible with high-resolution spectroscopy
and large galaxy/qso surveys.Comment: 16 pages, 16 figures. Version published in MNRAS. Analysis enlarged,
public catalogue now availabl
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