733 research outputs found
Neoclassical Growth, Environment and Technological Change: The Environmental Kuznets Curve
The paper investigates socially optimal patterns of economic growth and environmental quality in a neoclassical growth model with endogenous technological progress. In the model, the environmental quality affects positively not only to utility but also to production. However, cleaner technologies can be used in the economy whether a part of the output is used in environmentally oriented R&D. In this framework, if the initial level of capital is low then the shadow price of a cleaner technology is low relative to the cost of developing it given by the marginal utility of consumption and it is not worth investing in R&D. Thus, there will be a first stage of growth based only on the accumulation of capital with a decreasing environmental quality until the moment that pollution is great enough to make profitable the investment in R&D. After this turning point, if the new technologies are efficient enough, the economy can evolve along a balanced growth path with an increasing environmental quality. The result is that the optimal investment pattern supports an environmental Kuznets curve.Neoclassical Growth Model, Endogenous Technological Progress, External Effects, Environmental Kuznets Curve
Energy-Efficient Thermal-Aware Scheduling for RT Tasks Using TCPN
This work leverages TCPNs to design an energy-efficient, thermal-aware real-time scheduler for a multiprocessor system that normally runs in a low state energy at maximum system utilization but its capable of increasing the clock frequency to serve aperiodic tasks, optimizing energy, and honoring temporal and thermal constraints. An off-line stage computes the minimum frequency required to run the periodic tasks at maximum CPU utilization, the proportion of each task''s job to be run on each CPU, the maximum clock frequency that keeps temperature under a limit, and the available cycles (slack) with respect to the system with minimum frequency. Then, a Zero-Laxity online scheduler dispatches the periodic tasks according to the offline calculation. Upon the arrival of aperiodic tasks, it increases clock frequency in such a way that all periodic and aperiodic tasks are properly executed. Thermal and temporal requirements are always guaranteed, and energy consumption is minimized
A flexible framework for real-time thermal-aware schedulers using timed continuous petri nets
This work presents TCPN-ThermalSim, a software tool for testing Real-Time Thermal-Aware Schedulers1. This framework consists of four main modules. The first one helps the user to define the problem: Task set with periods, deadlines and worst case execution times in CPU cycles, along with the CPU characteristics, temperature and energy consumption. The second module is the Kernel simulation, which builds up a global simulation model according to the configuration module. In the third module, the user selects the scheduler algorithm. Finally the last module allows the execution of the simulation and present the results. The framework encompasses two modes: Manual and automatic. In manual mode the simulator uses the task set data provided in the first section. In automatic mode the task set is generated by parameterizing the integrated UUniFast algorithm
A novel tree-based algorithm to discover seismic patterns in earthquake catalogs
A novel methodology is introduced in this research study to detect seismic precursors. Based on an existing approach, the new
methodology searches for patterns in the historical data. Such patterns may contain statistical or soil dynamics information. It improves the
original version in several aspects. First, new seismicity indicators have been used to characterize earthquakes. Second, a machine learning
clustering algorithm has been applied in a very flexible way, thus allowing the discovery of new data groupings. Third, a novel search
strategy is proposed in order to obtain non-overlapped patterns. And, fourth, arbitrary lengths of patterns are searched for, thus
discovering long and short-term behaviors that may influence in the occurrence of medium-large earthquakes. The methodology has been
applied to seven different datasets, from three different regions, namely the Iberian Peninsula, Chile and Japan. Reported results show a
remarkable improvement with respect to the former version, in terms of all evaluated quality measures. In particular, the number of false
positives has decreased and the positive predictive values increased, both of them in a very remarkable manner.Ministerio de Ciencia y Tecnología TIN2011-28956-C00Junta de Andalucía P12-TIC-1728Instituto Ramón y Cajal (RYC) RYC-2012-1198
A Postprocessing methodology for direct normal irradiance forecasting using cloud information and aerosol load forecasts
A method for direct normal irradiance (DNI) forecasting for specific sites is proposed. It is based on the combination of a numerical weather prediction (NWP) model, which provides cloud information, with radiative transfer simulations fed with external aerosol forecasts. The NWP model used is the ECMWF Integrated Forecast System, and the radiative transfer information has been obtained from the Library of Radiative Transfer (libRadtran). Two types of aerosol forecasts have been tested: the global Monitoring Atmospheric Composition and Climate (MACC) model, which predicts five major components of aerosols, and the Dust Regional Atmospheric Model (BSC-DREAM8b) added to a fixed background calculated as the 20th percentile of the monthly mean of AERONET 2.0 observations from a different year. The methodology employed is valid for all meteorological situations, providing a stable and continuous DNI curve. The performance of the combined method has been evaluated against DNI observations and compared with the pure ECMWF forecasts at eight locations in the southern half of mainland Spain and the Canary Islands, which received high loadings of African dust for 2013 and 2014. Results for 1-day forecasts are presented. Although clouds play a major role, aerosols have a significant effect, but at shorter time scales. The combination of ECMWF and MACC forecasts gives the best global results, improving the DNI forecasts in events with high aerosol content. The regional BSC-DREAM8b yields good results for some extremely high dust conditions, although more reliable predictions, valid for any aerosol conditions, are provided by the MACC model
La inversión Matuyama-Brunhes en la secuencia de terrazas del río Jarama entre Velilla de San Antonio y Altos de la Mejorada, al SE de Madrid (España)
Al Este de la ciudad de Madrid, en el valle del río Jarama y entre Mejorada del Campo y Velilla de San Antonio se han estudiado las propiedades paleomagnéticas de una secuencia de terrazas comprendidas entre El Rasillo y Altos de la Mejorada, a lo largo de la autopista M-203 de reciente construcción. La cartografía geomorfológica realizada permitió separar además de la llanura aluvial a +4-5 m, terrazas a +20 m, +30-35 m, +60-65 m, +85-90 m, +105-110 m y +125-130 m. De ellas se muestrearon 5 niveles, a excepción de la de +20 m, en taludes frescos de la autovía que permiten situar a las terrazas con altitudes relativas igual o mayores a +60-65 m en el Chron Matuyama, mientras que las terrazas a +20 m y +30-35 m pertenecerían al Chron Brunhes (< 0.780 Ma). Dataciones por ESR en terrazas del valle del río Arlanzón en Burgos (Moreno et al., 2012), sugieren que en el valle del Jarama la inversión Matuyama-Brunhes podría establecerse entre el final de la sedimentación de la terraza a +60-65 m y el encajamiento de la terraza a +50-55 m subsiguiente, representada aguas arriba de Mejorada del Campo, en Marchamalo (Pérez-González, 1994)
Calibración de sensores de humedad capacitivos usando redes neuronales
X Jornadas de Investigación de la Zona no Saturada del Suelo, Salamanca (España), 2011El estudio de la variabilidad espacial de la
humedad del suelo a escala de parcela o cuenca agrícola
requiere el uso de redes de sensores de humedad de bajo
coste, que suelen mostrar una fiabilidad limitada y requieren
de calibraciones específicas, especialmente en suelos con
elevados contenidos en arcilla. El presente trabajo pretende
plantear una calibración más fiable de sondas de humedad
mediante un análisis mixto campo-laboratorio. Para la
calibración de campo se dispone de datos gravimétricos;
para la calibración en laboratorio se han usado columnas de
suelo inalterado que tras ser saturadas fueron desecadas en
un entorno controlado mientras se monitorizaba la
evolución de su peso y la de su humedad volumétrica,
medida con diferentes sondas capacitivas Decagon. Tras
obtener curvas de secado y la relación entre la humedad
gravimétrica y la volumétrica es posible realizar una
calibración mejorada específica para cada tipo de suelo. Las
redes neuronales son particularmente útiles para el
modelado de procesos físicos y el ajuste de modelos. En
este trabajo se propone el empleo de dichas herramientas
para obtener calibraciones para las sondas analizadas en el
tipo de suelo objeto de estudio. Los resultados muestran que
dichas calibraciones permiten mejorar la precisión de las
mediciones de humedad realizadas.The study of the spatial variability of soil
water content at agricultural plot or catchment scales
requires the use of low-cost soil water content sensor
networks, which usually show a limited reliability and
require specific calibrations, specially for soils with a high
clay content. This work proposes a more reliable calibration
of soil water content probes with a laboratory analysis.
Minimally disturbed soil columns were saturated with water
and dried in a controlled environment while monitorizing
the evolution of their volumetric soil water content (with
different capacitive Decagon Probes) and weights. After
obtaining the drying curves and the relation between the
volumetric and the measured gravimetric soil water contents
it is possible to achieve an improved calibration specific for
different kinds of soil. Neural networks are especially
interesting for the modeling of physical processes and
model adjustment. In this work, these tools were used in
order to obtain improved calibrations for the analyzed
probes in the studied soil type. Results show that this
calibration improves the accuracy and pMinisterio de Ciencia e Innovación AGL2009 C03-03Junta de Andalucía AGR-478
Dynamic changes in the lower Gállego River (Ebro Basin, NE Spain) and their relationship with anthropic activities and the quaternary substrate
The lower Gállego River has been strongly degraded since the 1960s due to human activity (gravel mining, dump accumulation, channeling works), which has produced a deep channel incision. Although these humandriven processes are usually reported in fluvial bibliography, in this case, more complex results are observable. For instance, regarding the depth and incision rates, we observed no relationship between the most anthropically impacted areas and the sections with the deepest incisions; moreover, the deepening process continues 40 years after the human interventions ceased. The reason for this maladjustment is the role played by the exhumation of the underlying Pleistocene substrate, affected by the synsedimentary processes of karstification. The appearance of paleodolines filled with fine sediments on the incision bottom and sides is the main factor conditioning the continuity and magnitude of the process. Besides, these paleodepressions direct the river dynamics and course, thus favoring its widening when they appear and causing the development of a new riverbed (Qt13) while the 1960s floodplain (Qt12) is becoming an old terrace located between 5 and 11 m above the new alluvial bottom. There are no previous records about this kind of consequences in the regional fluvial dynamics.
El curso bajo del río Gállego ha sido fuertemente degradado desde los años 1960 por la actividad antrópica (extracción de áridos, acumulaciones de escombros, obras de encauzamiento) que ha conducido a una fuerte incisión. Aunque este tipo de procesos inducidos por el hombre son habituales en la bibliografía fluvial, en este caso se aprecian efectos más complejos. Son, por ejemplo, la profundidad y velocidad de la incisión, la falta de relación entre puntos de máxima intervención y los de mayor incisión o la continuidad del proceso cuarenta años después de cesar ese tipo de acciones. La respuesta a estos desajustes está en el papel que está jugando la exhumación del sustrato pleistoceno infrayacente, afectado por procesos sinsedimentarios de karstificación. La aparición de paleodolinas rellenas de sedimentos finos en el fondo y laterales de la incisión es actualmente el principal determinante de su importancia y continuidad. Además, estas paleodepresiones dirigen la dinámica y trazado del río y puntualmente favorecen ensanchamientos laterales. Esto propicia la aparición de un nuevo lecho (Qt13) a medida que el lecho de los años 1960 (Qt12) va quedando como una terraza colgada entre 5 y 11 m sobre el nuevo fondo aluvial. No hay antecedentes de este tipo de consecuencias en la dinámica fluvial regional
A new strategy to design SIW-fed arrays
In this work, a new full-wave strategy, with very low
iteration times, is proposed for the optimization and design of
antenna arrays fed by substrate integrated waveguides. The
device is decomposed into fixed and modifiable (to be optimized)
sections, whose generalized scattering matrices are precomputed.
The response of the array is calculated by considering firstly only
the interactions between the fixed sections, which are then
coupled to the modifiable ones in each iteration of an
optimization process. To validate the proposed strategy, a
transversal 16-slot antenna array, placed on the top plate of a
substrate integrated waveguide, has been designed. A speed-up
factor of over 2000 times, compared to general purpose
commercial software, has been obtained in this optimization
process. The final design presents a 1.05 GHz bandwidth under -
10 dB in terms of |S11|, a maximum realized gain of 17.5 dBi at 17
GHz, and a 99.95% maximum efficiency (without dielectric and
conductor losses).
Index Terms—Addition theorems, cylindrical modes, spherical
modes, optimization process, antenna array, substrate integrated
waveguide (SIW)
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