Monte Carlo model of the uncertainty of SEA loss factors

Finite Element Methods are widely used to model vibro-acoustic systems, but as the modal density becomes higher this type of model becomes inaccurate and impractical. This is why in the high modal density region the use of Statistical Energy Analysis (SEA) models has become increasingly popular. SEA has some obvious advantages such as its simple formal expression, being based on linear equation systems or the reduced number of variables involved. But SEA has drawbacks as well, such as the absence of local information or the necessity of frequency averaging. A key quantity in SEA models is the loss factor. This takes into account the energy dissipated within a given subsystem or when power flows from one subsystem to another. Even though analytical expressions exist for a number of subsystems of differing nature, the measurement of the loss factor is still advisable and a necessity for a large number of cases. The most commonly used method of measuring loss factors is the Power Injection Method. This method is based on the injection of power into every single subsystem in sequence while the energy in each subsystem is measured. In spite of its simplicity, there remain a number of problems where the accuracy of the results is influenced by various practical issues. In this paper, a Monte Carlo model is used to describe the uncertainty of a two subsystemproblem consisting of two planar elements connected along one side. The influence of the input variables is studied and the conditioning of the coefficient matrix that model the system is also taken into accoun

Flutter margin with non-linearities: real-time prediction of flutter onset speed

The present article shows a procedure to predict the flutter speed based on real-time tuning of a quasi non-linear aeroelastic model. A two-dimensional non-linear (freeplay) aeroeslastic model is implemented inMatLab/Simulink with incompressible aerodynamic conditions. A comparison with real compressible conditions is provided. Once the numerical validation is accomplished, a parametric aeroelastic model is built in order to describe the proposed procedure and contribute to reduce the number of flight hours needed to expand the flutter envelope

Inducing narrative tension in the viewer through suspense, surprise, and curiosity

Producción CientíficaResearch into narrative tension is of interest in terms of the progress of knowledge of the processes and mechanisms by which stories are received and enjoyed. We have created four versions of an audiovisual story with three different structures of fiction (suspense, surprise, curiosity) and one of non-fiction. We have investigated the effects of the narrative tension of these stories with four groups of subjects (N=94). The results show that the organization of the stories, depending on their structures of suspense, surprise, or curiosity, induces narrative tension, while the non-fictional story, induces cognitive and affective effects of another kind. Narrative tension appears during narrative progression. It is manifested by cognitive-affective responses that include anticipations, diagnoses, retrospections, and emotions. In narrative tension, curiosity plays a triggering and organizing role in suspense and surprise. The emotions and cognitions that result from narrative tension during plot construction underpin the experience of enjoyment. The Multidimensional Narrative Tension Theory of Enjoyment that emerges from this research allows establishing connections between narrative theory concerned with narrative progression and plot, the psychology of interest, and the psychology of media enjoyment

Air gap influence on the vibro-acoustic response of Solar Arrays during launch

One of the primary elements on the space missions is the electrical power subsystem, for which the critical component is the solar array. The behaviour of these elements during the ascent phase of the launch is critical for avoiding damages on the solar panels, which are the primary source of energy for the satellite in its final configuration. The vibro-acoustic response to the sound pressure depends on the solar array size, mass, stiffness and gap thickness. The stowed configuration of the solar array consists of a multiple system composed of structural elements and the air layers between panels. The effect of the air between panels on the behaviour of the system affects the frequency response of the system not only modifying the natural frequencies of the wings but also as interaction path between the wings of the array. The usual methods to analyze the vibro-acoustic response of structures are the FE and BE methods for the low frequency range and the SEA formulation for the high frequency range. The main issue in the latter method is, on one hand, selecting the appropriate subsystems, and, on the other, identifying the parameters of the energetic system: the internal and coupling loss factors. From the experimental point of view, the subsystems parameters can be identified by exciting each subsystem and measuring the energy of all the subsystems composing the Solar Array. Although theoretically possible, in practice it is difficult to apply loads on the air gaps. To analyse this situation, two different approaches can be studied depending on whether the air gaps between the panels are included explicitly in the problem or not. For a particular case of a solar array of three wings in stowed configuration both modelling philosophies are compared. This stowed configuration of a three wing solar arrays in stowed configuration has been tested in an acoustic chamber. The measured data on the solar wings allows, in general, determining the loss factors of the configuration. The paper presents a test description and measurements on the structure, in terms of the acceleration power spectral density. Finally, the performance of each modelling technique has been evaluated by comparison between simulations with experimental results on a spacecraft solar array and the influence on the apparent properties of the system in terms of the SEA loss factors has been analyse

Capacidad tecnológica e internacionalización de la empresa: una aproximación desde la teoría de recursos y capacidades

La capacidad de una empresa para entrar y vender productos en los mercados internacionales requiere de un importante nivel de competitividad, la cual reside fundamentalmente en los recursos intangibles de la empresa. Así, partiendo de la teoría de recursos y capacidades se analiza la influencia de la capacidad tecnológica de la empresa sobre la decisión de exportar y sobre la intensidad exportadora. Los resultados muestran que las innovaciones de productos, las patentes y las innovaciones de proceso influyen positiva y significativamente tanto en la decisión de exportar como en la intensidad exportadora. La intensidad de gastos en I+D no resulta significativa en la decisión de exportar aunque sí en la intensidad exportadora. JEL: F20, D21, L60A firm’s capacity to enter and sell products in international markets requires an important degree of competitiveness, which fundamentally resides in its intangible resources. Thus, in the current work and drawing from the resource-based view, we analyse the influence of a firm’s technological capacity on both its decision to export and its export intensity from a sample of Spanish manufacturing firms using nonlinear regression models. Our findings show that product innovations, patents and process innovations positively and significantly affect both the decision to export and the export intensity. R&D spending intensity is not significant in the decision to export, although it is significant in export intensity. JEL: F20, D21, L6

Non-axisymmetric oscillations of liquid bridges

The main characteristics of the non-axisymmetric oscillations of a liquid bridge have been considered: free frequencies, deformation modes and the influence of an outer liquid. Oscillations of this kind do not show stability changes. The Plateau technique has been used to obtain the resonant frequencies of the bridge when lateral perturbations are imposed. The results obtained are in good agreement with the theoretical ones when the influence of the outer liquid is considered. Moreover, lateral oscillations observed in experiments performed with liquid bridges in space can be explained with this model

Incidencia de la estacionalidad de la demanda turística en las provincias andaluzas

La estacionalidad de la demanda turística es una materia de estudio muy relevante para los responsables de marketing de las organizaciones y destinos turísticos. En el presente trabajo tratamos de analizar la estacionalidad de la demanda turística de Andalucía y, especialmente, de las provincias andaluzas. Procuramos comprobar los niveles de estacionalidad de la demanda turística en función de distintas variables, de forma independiente, como son el número de visitantes, los días de estancia media y el gasto medio por turista. Entre los resultados obtenidos se observa que la estacionalidad de la demanda turística en Andalucía, en su conjunto, ha aumentado en cada una de las tres variables estudiadas y su evolución se guía por el modelo de turismo de sol y playa. Pero también hay varias provincias que presentan unos resultados diferentes, atendiendo a unas características particulares en cada caso.The seasonal concentration in tourism demand is very important to the marketers of enterprises and destinations. The main purpose of this paper is to analyse seasonality in tourism demand in Andalusia and paying particular attention to andalusian provinces. We examine the seasonality in tourism demand with regard to the number of tourists, the average days of stay and the average expenditure of tourist. The results suggest that seasonality in tourism demand in Andalusia increase in the three variables and its trend is based on the model of tourism of sun and beach. But there are several provinces with different results, in accordance with their specific characteristics

Diseño de un sistema borroso para la detección de intrusos

[ES] En los últimos años, debido al incremento en el uso de los ordenadores y la emergencia del comercio electrónico, la detección de intrusos se ha convertido en una prioridad importante, pues no resulta técnicamente factible construir un sistema invulnerable. La hipótesis de la investigación es que la Lógica Borrosa es capaz de producir "mejores" reglas que incrementen la flexibilidad y robusted de los sistemas de auditoría informática. De hecho, los Sistemas Basados en Reglas Borrosas (SBRBs) han demostrado ser una herramienta muy efectiva para el diseño de Sistemas Inteligentes de Análisis de Datos para problemas de control, clasificación, modelado etc., en aquellos contextos donde la información y/o los datos están afectados de imprecisión no probabilística. De esta forma, el principal propósito del presente del trabajo consistirá en elaborar un modelo de Sistema Experto Borroso aplicado a la Detección de Intrusos, para ello nuestra propuesta consiste en profundizar en los dos aspectos siguientes: el diseño de un SBRB y estudiar la adaptación de estos modelos en "minería de datos" relativos a la detección de intrusos

Diegetic and non-diegetic surprises, and their effect on liking, long-term recall and comprehension in narrative television commercials

The aim of this experiment is to classify surprises in audiovisual narratives, and to measure the efficacy of surprise in audiovisual stories in terms of liking, long-term recall and comprehension in television commercials. The theoretical analysis leads to distinguish 3 types of audiovisual narrative surprises: non-diegetic, diegetic implausible and diegetic plausible. In order to test these types of surprises with complete and homogeneous stories in terms of duration, and to show many of these types of surprises to each participant, 16 narrative television commercials (M=40,68 seconds) were used as stimuli in this study. The experimental design was a 4 groups (3 groups of surprise, and 1 non-surprise group, 4 stories each) fully randomised experiment (N=120, Age: 18-24). The results showed that surprise had a significant enhancing effect on liking, on the day of the viewing (c² (3,N=480)=5.83, p=0.12), and one month after (c² (3,N=480)=10.38, p=.016); an ANOVA test showed a significant relation between surprise and the degree of comprehension (F(1,480)=12.14),

Appreciation of online teaching-learning in times of COVID-19 by Spanish families

[EN] The study analyses the satisfaction of Spanish families with children in compulsory education (from 6 to 16 years old) after the change from face-to-face to digital teaching due to the COVID-19. Using a simple random sampling of 2,150 individuals from all over Spain: differences in satisfaction are observed among families who take their children to a public, subsidized, or private center; it also analyzesthe impression on the methodology of the teaching system in the new context.[ES] El estudio analiza la satisfacción de las familias españolas con hijos en educación obligatoria (de 6 a 16 años) tras el paso de docencia presencial a docencia digital a causa del COVID-19. Mediante un muestreo aleatorio simple de 2.150 individuos de toda España: se observan diferencias de satisfacción entre las familias que llevan a sus hijos a un centro público, concertado o privado; también analiza la impresión sobre la metodología del sistema de enseñanza en el nuevo contextoCabrera, M.; Díez-Somavilla, R.; López-Navarrete, AJ. (2021). Apreciación de la enseñanza-aprendizaje online en tiempos de COVID-19 por parte de las familias españolas. Espacios. 42(1):246-258. https://doi.org/10.48082/espacios-a21v42n01p20S24625842