Del software libre al conocimiento libre: argumentos de carácter técnico para aspirar a una sociedad digital universal, igualitaria y libre

Cuando el movimiento del Software Libre comienza a ser conocido fuera del ámbito de los técnicos y especialistas, surge un nuevo movimiento sobre premisas similares para superar barreras en la actual sociedad de la información y ofrecer el Conocimiento Libre para todos. Las administraciones públicas de todo el mundo son, precisamente, las que más pueden hacer por el despliegue de estos dos movimientos y las que pueden disfrutar de ventajas como incrementar la eficiencia del servicio que prestan al ciudadano, optimizar sus recursos y, sobre todo, disponer de la posibilidad del acceso universal a la sociedad de la información y del conocimiento verdaderamente libres. Reflexionamos también sobre las motivaciones de los autores del software y conocimiento libres, agentes fundamentales para que estos dos movimientos logren sus objetivos

Sobre aproximación y extensión suave en espacios de Banach y aplicaciones a variedades Banach-Finsler

Tesis inédita de la Universidad Complutense de Madrid, Facultad de Ciencias Matemáticas, Departamento de Análisis Matemático, leída el 21-06-2012El marco de esta memoria es la teoría de diferenciabilidad en espacios de Banach y en variedades de tipo Banach-Finsler. En ella nos ocupamos de varias cuestiones diferentes que, como iremos viendo, están muy relacionadas entre sí. El primer problema que abordamos trata de caracterizar los espacios de Banach separables donde existen funciones meseta diferenciables que localmente dependen de un número finito de coordenadas. Recordemos que una función meseta definida en un espacio de Banach X es una función real-valuada f : X ! R tal que su soporte es no vacío y acotado, es decir, existe un elemento x 2 X tal que f(x) 6= 0 y la clausura del conjunto fx 2 X : f(x) 6= 0g es acotada. La existencia de una función meseta con buenas condiciones nos proporciona una gran cantidad de propiedades geométricas y de herramientas que no disponemos en otros espacios de Banach. Un buen ejemplo es un espacio de Banach el cual admite una función meseta diferenciable, ya que ésta implica que el espacio sea Asplund y admita particiones de la unidad diferenciables. La propiedad en la que nosotros estamos interesados es la siguiente: una función f : X ! R, definida en un espacio de Banach, localmente depende de un número finito de coordenadas (LFC, para acortar) siempre que localmente se pueda factorizar a través de espacios de dimensión finita, es decir, para todo x 2 X, existan un entorno U de x, una cantidad finita de funcionales ff1; : : : ; fng X y una función continua g : Rn ! R tales que f(y) = g(f1(y); : : : ; fn(y)) para todo y 2 U...Depto. de Análisis Matemático y Matemática AplicadaFac. de Ciencias MatemáticasTRUEunpu

The relation between electricity and natural gas spot prices in Spain: cointegration and volatility spill-over analysis

Master in Economics: Empirical Applications and Policies. Academic Year 2020-2021The relation between electricity and natural gas prices got increased attention recently, after their joint rise in many European countries. The present Master Thesis explains the theoretical relation between both markets in Spain given the significant amount of natural gas devoted to electricity generation. Our main contribution is the analysis of the natural gas Iberian hub, not explored in the literature yet, whose liquidity is also an element of the analysis. In order to quantify the relation between these two markets, we carry out a cointegration analysis, by means of a Johansen and Juselius Cointegration test and a VECM approach. The results show that there are strong common long-term dynamics between both price series, and that, in the short-term, gas prices have a larger impact on electricity prices than electricity prices on natural gas prices. Additionally, we study the volatility spill-over between the markets using three different extensions of the Multivariate GARCH. The results show that there is a strong volatility spill-over between the markets, but the models turn out to be non-stable, so further research in this sense is needed

Origin of passivation in hole-selective transition metal oxides for crystalline silicon heterojunction solar cells

Transition metal oxides (TMOs) have recently demonstrated to be a good alternative to boron/phosphorous doped layers in crystalline silicon heterojunction solar cells. In this work, the interface between n-type c-Si (n-Si) and three thermally evaporated TMOs (MoO3, WO3, and V2O5) was investigated by transmission electron microscopy, secondary ion-mass, and x-ray photoelectron spectroscopy. For the oxides studied, surface passivation of n-Si was attributed to an ultra-thin (1.9–2.8 nm) SiOx~1.5 interlayer formed by chemical reaction, leaving oxygen-deficient species (MoO, WO2, and VO2) as by-products. Carrier selectivity was also inferred from the inversion layer induced on the n-Si surface, a result of Fermi level alignment between two materials with dissimilar electrochemical potentials (work function difference ¿¿ = 1 eV). Therefore, the hole-selective and passivating functionality of these TMOs, in addition to their ambient temperature processing, could prove an effective means to lower the cost and simplify solar cell processing.Postprint (author's final draft

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Influence of loudspeaker directivity on the measurement uncertainty

One of the most significant aspects of a building’s acoustic behavior is the airborne sound insulation of the room façades, since this determines the protection of its inhabitants against environmental noise. For this reason, authorities in most countries have established in their acoustic regulations for buildings the minimum value of sound insulation that must be respected for façades. In order to verify compliance with legal requirements it is usual to perform acoustic measurements in the finished buildings and then compare the measurement results with the established limits. Since there is always a certain measurement uncertainty, this uncertainty must be calculated and taken into account in order to ensure compliance with specifications. The most commonly used method for measuring sound insulation on façades is the so-called Global Loudspeaker Method, specified in ISO 140-5:1998. This method uses a loudspeaker placed outside the building as a sound source. The loudspeaker directivity has a significant influence on the measurement results, and these results may change noticeably by choosing different loudspeakers, even though they all fulfill the directivity requirements of ISO 140-5. This work analyzes the influence of the loudspeaker directivity on the results of façade sound insulation measurement, and determines its contribution to measurement uncertainty. The theoretical analysis is experimentally validated by means of an intermediate precision test according to ISO 5725-3:1994, which compares the values of sound insulation obtained for a façade using various loudspeakers with different directivitie

Estimation of specific cutting energy in an S235 alloy for multi-directional ultrasonic vibration-assisted machining using the Finite Element Method

The objective of this work is to analyze the influence of the vibration-assisted turning process on the machinability of S235 carbon steel. During the experiments using this vibrational machining process, the vibrational amplitude and frequency of the cutting tool were adjusted to drive the tool tip in an elliptical or linear motion in the feed direction. Furthermore, a finite element analysis was deployed to investigate the mechanical response for different vibration-assisted cutting conditions. The results show how the specific cutting energy and the material’s machinability behave when using different operational cutting parameters, such as vibration frequency and tool tip motion in the x-axis, y-axis, and elliptical (x-y plane) motion. Then, the specific cutting energy and material’s machinability are compared with a conventional turning process, which helps to validate the finite element method (FEM) for the vibration-assisted process. As a result of the operating parameters used, the vibration-assisted machining process leads to a machinability improvement of up to 18% in S235 carbon steel. In particular, higher vibration frequencies were shown to increase the material’s machinability due to the specific cutting energy decrease. Therefore, the finite element method can be used to predict the vibration-assisted cutting and the specific cutting energy, based on predefined cutting parameters.Peer ReviewedPostprint (published version

Immediate Effects of Bilateral Sacroiliac Joint Manipulation on Plantar Pressure Distribution in Asymptomatic Participants

[EN] Objective: To investigate the immediate effects of manipulation of bilateral sacroiliac joints (SIJs) on the plantar pressure distribution in asymptomatic participants in the standing position. Design: Randomized, controlled, double-blind clinical trial. Participants: Sixty-two asymptomatic men and women (mean age, 20.66 – 2.56 years) randomly assigned to 2 groups. Interventions: The experimental group underwent mobilization without tension of the hips in the supine position and high-velocity, low-amplitude manipulation in the SIJs bilaterally. The control group underwent only mobilization, without tension of the hips in supine position. Outcome Measures: Pre- and postintervention outcomes measured by an assessor blinded to the treatment allocation of the participants included a baropodometric analysis performed by using a force platform. Baseline between-group differences were examined with a Kolmogorov-Smirnov test. A chi-square test was used for categorical data. Analysis of covariance (ANCOVA) was used to assess differences between groups, with the preintervention value as covariant (95% confidence level). Results: At baseline, no variables significantly differed between groups. Baropodometric analysis showed statistically significant differences in the location of the maximum pressure point in the experimental group ( p = 0.028). Pre- and postintervention analysis with ANCOVA showed statistically significant differences between both groups in the left hindfoot load percentage (interaction p = 0.0259; ANCOVA p = 0.0277), right foot load percentage (ANCOVA p = 0.0380), and surface of the right forefoot (interaction p = 0.0038). There was also a significant effect in the variables that analyze the entire foot (left foot: surface [interaction p = 0.0452], percentage of load [ANCOVA p = 0.0295]) and between both groups (right foot: weight [interaction p = 0.0070; ANCOVA p = 0.0296]). Conclusions: Sacroiliac joint manipulation applied bilaterally in asymptomatic persons resulted in immediate changes in load distribution on plantar support in the standing position. Study limitations and suggestions for future studies are discussed