Design of an analog/digital truly random number generator

An analog-digital system is presented for the generation of truly random (aperiodic) digital sequences. This model is based on a very simple piecewise-linear discrete map which is suitable for implementation using monolithic analog sampled-data techniques. Simulation results are given illustrating the optimum choice of the model parameters. Circuit implementations are reported for the discrete map using both switched-capacitor (SC) and switched-current (SI) techniques. The layout of a SI prototype in a 3-μm n-well double-polysilicon double-metal technology is included

Crack-Depth Prediction in Steel Based on Cooling Rate

One criterion for the evaluation of surface cracks in steel welds is to analyze the depth of the crack, because it is an effective indicator of its potential risk. This paper proposes a new methodology to obtain an accurate crack-depth prediction model based on the combination of infrared thermography and the 3D reconstruction procedure. In order to do this, a study of the cooling rate of the steel is implemented through active infrared thermography, allowing the study of the differential thermal behavior of the steel in the fissured zone with respect to the nonfissured zone. These cooling rate data are correlated with the real geometry of the crack, which is obtained with the 3D reconstruction of the welds through a macrophotogrammetric procedure. In this way, it is possible to analyze the correlation between cooling rate and depth through the different zones of the crack. The results of the study allow the establishment of an accurate predictive depth model which enables the study of the depth of the crack using only the cooling rate data. In this way, the remote measure of the depth of the surface steel crack based on thermography is possible

Learning methodology based on weld virtual models in the mechanical engineering classroom

13 pp.Welding inspection activities within engineering degree programs are usable in practice. The competences acquired through these are usually contextualized in laboratory environments, using for its physical samples of welds, which used to be are scarce and expensive. In this study, a new methodology based on threedimensional macro‐photogrammetric models of welds is designed and actively implemented in the classroom, with students of mechanical engineering to evaluate different aspects about the suitability and learning performance of this novel methodology. To obtain the research conclusions, the activities have been chosen to evaluate four important aspects of it: usability, learning, motivation, and scalability. Results demonstrate that the adequate acceptation of the novel methodology studied, making possible new approaches for the acquisition of the competences related the welding inspection in the engineering education contextS

Do envy and compassion pave the way to unhappiness? Social preferences and life satisfaction in a Spanish city

Mounting evidence shows that people’s self-reported life satisfaction (LS) is negatively related to income inequality. Under the interpretation that the relationship between macro-level variables and LS reflects individuals’ social preferences, this finding indicates that most people display inequality-averse preferences. We explore the relationship between self-reports on inequality aversion and LS in a citywide representative survey/experiment conducted in Spain. If self-reported well-being can be used to infer people’s social preferences, LS should correlate negatively with both “envy” and “compassion” scores (i.e., how much one suffers from disadvantageous and advantageous inequality, respectively). We find that LS relates negatively to envy but positively to compassion, which would imply that suffering from observing poorer others, paradoxically, increases well-being. Using an incentivized Dictator Game as a measure of generous behavior, we reject the hypothesis that the positive link between compassion and LS is actually driven by generosity. We discuss how these findings could indicate that the way LS is used to assess social preferences in the population should be revised

Sedimentological study of Galicia coast: JI. Relation-ship between the distribution of grain size and the biogenic carbonate content in Pontevedra and Arousa beaches.

[Resumen] Dentro del estudio de los diferentes medios de depósitos sedimentarios de las Rías Gallegas, se presenta una distribución del contenido en carbonatos biogénicos así como las variaciones granulométricas del sector intermareal de las playas de Pontevedra y Arosa. Los puntos de muestreo fueron seleccionados en función del grado de exposición y condiciones de alta energía (zonas abiertas), y de baja energía (zonas interiores). Se levantaron perfiles topográficos en un total de 15 playas; en cada perfil se tomaron, como promedio, 3 muestras comprendidas entre los niveles de pleamar y bajamar, considerando puntos equivalentes para cada una de las playas. Los resultados obtenidos muestran en general una homogeneidad en cuanto a tamaño de grano, del orden de 2 a 0.25 mm, es decir, fracción media-gruesa. Es constante la presencia de los valores más finos hacia la parte alta de cada perfil. El contenido en carbonatos oscila entre un 20 y un 40 O/o para aquellas estaciones de muestreo situadas en zonas abiertas, mientras que en aquellas otras situadas hacia el interior su contenido no sobrepasa, en general, el 5 o/o. Estos valores pueden ser interpretados como resultado de la ubicación geográfica y su dinámica, actuando como indicador que puede ser extensible al resto del litoral gallego.[Abstract] A distribution of the biogenic carbonatic content and grain size for the intertidal zone of the beaches of the Ria de Pontevedra and Ria de Arosa is presented in this papero Sampling stations were chosen to reflect the different exposures and energy: high energy (open zones) and low energy (inner zones). Morphology of 15 beaches was determined by topographic profiling, with an average of 3 samples between high-water mark and low-water mark in each profile. This way, equivalent points in the different beaches can be compared. The results show a general grain-size homogneity with a predominance of the medium-coarse fraction, about 2-0.25 mm. A finer grain size is usually found in the upper part of each profile. The carbonatic content range is 20-40 O/o in open zones, whereas the content is less than 5 O/o in beaches towards the inner zones. This values are significant with respect to the geographical position of the beaches in each ria and the different dynamics. They are, then, an index that could be applied to the study of the whole Galician coast

Interaction Effects on the Magneto-optical Response of Magnetoplasmonic Dimers

The effect that dipole-dipole interactions have on the magneto-optical (MO) properties of magnetoplasmonic dimers is theoretically studied. The specific plasmonic versus magnetoplasmonic nature of the dimer's metallic components and their specific location within the dimer plays a crucial role on the determination of these properties. We find that it is possible to generate an induced MO activity in a purely plasmonic component, even larger than that of the MO one, therefore dominating the overall MO spectral dependence of the system. Adequate stacking of these components may allow obtaining, for specific spectral regions, larger MO activities in systems with reduced amount of MO metal and therefore with lower optical losses. Theoretical results are contrasted and confirmed with experiments for selected structures

Pulse-based, Periodic MPC for Irrigation in Smart and Sustainable Agriculture

The growing population, together with global warming and the difficulty of accessing water, makes the increase of efficient and sustainable agriculture a priority. Undoubtedly, the recent development of low-cost IoT-based sensors and actuators presents great opportunities in this direction, since these devices can be easily deployed to implement advanced monitoring and irrigation control techniques at a farm scale. This paper proposes a pulse-based, periodic, economic predictive controller. Its goal is to find the irrigation pulse trains that optimize water and energy consumption while ensuring adequate levels of soil moisture for the crops. For this purpose, the developed MPC makes use of soil moisture data at different depths, sent by a set of field sensors, and formulates a constrained optimization problem that takes into account water costs, electricity prices, and an accurate dynamical nonlinear agro-hydrological model. Its performance is tested by simulating real case studies, which show that water and energy consumption can be significantly reduced

Espacio y poder político : la construcción territorial del Reino de Murcia en la Edad Moderna

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