Evaluating the more suitable ISM frequency band for iot-based smart grids: a quantitative study of 915 MHz vs. 2400 MHz

IoT has begun to be employed pervasively in industrial environments and critical infrastructures thanks to its positive impact on performance and efficiency. Among these environments, the Smart Grid (SG) excels as the perfect host for this technology, mainly due to its potential to become the motor of the rest of electrically-dependent infrastructures. To make this SG-oriented IoT cost-effective, most deployments employ unlicensed ISM bands, specifically the 2400 MHz one, due to its extended communication bandwidth in comparison with lower bands. This band has been extensively used for years by Wireless Sensor Networks (WSN) and Mobile Ad-hoc Networks (MANET), from which the IoT technologically inherits. However, this work questions and evaluates the suitability of such a "default" communication band in SG environments, compared with the 915 MHz ISM band. A comprehensive quantitative comparison of these bands has been accomplished in terms of: power consumption, average network delay, and packet reception rate. To allow such a study, a dual-band propagation model specifically designed for the SG has been derived, tested, and incorporated into the well-known TOSSIM simulator. Simulation results reveal that only in the absence of other 2400 MHz interfering devices (such as WiFi or Bluetooth) or in small networks, is the 2400 MHz band the best option. In any other case, SG-oriented IoT quantitatively perform better if operating in the 915 MHz band.This research was supported by the MINECO/FEDER project grants TEC2013-47016-C2-2-R (COINS) and TEC2016-76465-C2-1-R (AIM). The authors would like to thank Juan Salvador Perez Madrid nd Domingo Meca (part of the Iberdrola staff) for the support provided during the realization of this work. Ruben M. Sandoval also thanks the Spanish MICINN for an FPU (REF FPU14/03424) pre-doctoral fellowship

Debates—Stochastic subsurface hydrology from theory to practice: why stochastic modeling has not yet permeated into practitioners?

This is the peer reviewed version of the following article: [Sanchez-Vila, X., and D. Fernàndez-Garcia (2016), Debates—Stochastic subsurface hydrology from theory to practice: Why stochastic modeling has not yet permeated into practitioners?, Water Resour. Res., 52, 9246–9258, doi:10.1002/2016WR019302], which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1002/2016WR019302/abstract. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-ArchivingWe address modern topics of stochastic hydrogeology from their potential relevance to real modeling efforts at the field scale. While the topics of stochastic hydrogeology and numerical modeling have become routine in hydrogeological studies, nondeterministic models have not yet permeated into practitioners. We point out a number of limitations of stochastic modeling when applied to real applications and comment on the reasons why stochastic models fail to become an attractive alternative for practitioners. We specifically separate issues corresponding to flow, conservative transport, and reactive transport. The different topics addressed are emphasis on process modeling, need for upscaling parameters and governing equations, relevance of properly accounting for detailed geological architecture in hydrogeological modeling, and specific challenges of reactive transport. We end up by concluding that the main responsible for nondeterministic models having not yet permeated in industry can be fully attributed to researchers in stochastic hydrogeology.Peer ReviewedPostprint (author's final draft

DIRECT DETECT - sistema revolucionario para la cuantificación de moléculas

Comunicaciones a congreso

Stochastic estimation of hydraulic transmissivity fields using flow connectivity indicator data

This is the peer reviewed version of the following article: [Freixas, G., D. Fernàndez-Garcia, and X. Sanchez-Vila (2017), Stochastic estimation of hydraulic transmissivity fields using flow connectivity indicator data, Water Resour. Res., 53, 602–618, doi:10.1002/2015WR018507], which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1002/2015WR018507/abstract. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.Most methods for hydraulic test interpretation rely on a number of simplified assumptions regarding the homogeneity and isotropy of the underlying porous media. This way, the actual heterogeneity of any natural parameter, such as transmissivity ( math formula), is transferred to the corresponding estimates in a way heavily dependent on the interpretation method used. An example is a long-term pumping test interpreted by means of the Cooper-Jacob method, which implicitly assumes a homogeneous isotropic confined aquifer. The estimates obtained from this method are not local values, but still have a clear physical meaning; the estimated math formula represents a regional-scale effective value, while the log-ratio of the normalized estimated storage coefficient, indicated by math formula, is an indicator of flow connectivity, representative of the scale given by the distance between the pumping and the observation wells. In this work we propose a methodology to use math formula, together with sampled local measurements of transmissivity at selected points, to map the expected value of local math formula values using a technique based on cokriging. Since the interpolation involves two variables measured at different support scales, a critical point is the estimation of the covariance and crosscovariance matrices. The method is applied to a synthetic field displaying statistical anisotropy, showing that the inclusion of connectivity indicators in the estimation method provide maps that effectively display preferential flow pathways, with direct consequences in solute transport.Peer ReviewedPostprint (published version

An extension to the CORBA Audio/Video Streaming Service: A QoS adaptive middleware

The CORBA audio/video (A/V) Streaming Service has been designed to implement and integrate open distributed multimedia applications. In this paper, a set of impairments resulting of the original A/V service are identified. To overcome such limitations, we propose an extension to the specification of the A/V Streaming Service. It defines a flexible architecture creating a framework that simplifies the implementation of applications handling audio/video flows. To evaluate our service extension we develop middleware objects of an application to control and manage uncompressed video data flows with strict time restrictions. Empirical results obtained by executing this application are also presented and discussed.This work has been supported by project grant TEC2007-67966-01/TCM (CON-PARTE-1) and it is also developed in the framework of “Programa de Ayudas a Grupos de Excelencia de la Región de Murcia, de la Fundación Séneca, Agencia de Ciencia y Tecnología de la RM”

Lo que se verá a mi vera de Vera. Probable etimología vera del apelativo y topónimos homónimos

Se muestra en este trabajo cómo una vez más la homonimia y la paronimia han podido ocultar y soterrar la vera (= verdadera) génesis del sustantivo común vera, así como la de algunos topónimos que parecen contener esa misma voz. Ha sido a partir del más conocido de ellos, el almeriense Vera, de origen prerromano, sobre el que se han construido buena parte de las argumentaciones etimológicas de los demás topónimos, y también del apelativo en cuestión. Sin embargo, las explicaciones de esos nombres de lugar, entre los que también estarían los Beira gallego-portugueses, y de los sustantivos correspondientes, pueden ser diferentes de las que ha hecho suponer el nombre de la población almeriense. Palabras clave: toponimia; etimología; homonimia; vera; beira.This paper shows how once again homonymy and paronymy might have hidden the true origin of the common noun vera, as well as that of some place names that appear to contain the same word. From the best known of them, Vera in Almeria, of pre-Roman origin, have been based many of the etymological arguments on the other toponyms, and on the noun vera itself. However, the explanations of those place names, among which the Galician and Portuguese Beira would also appear, and of the corresponding nouns, may be different from those which are thought to have originated from the name of the Andalusian village. Keywords: toponymy; etymology; homonymy; vera; beira

Reproductive biology of "Helianthemum apennium" (L.) Mill. and "H. caput-felis" Boiss. (Cistaceae) from Mallorca (Balearic Island, Spain)

El estudio de la biología reproductiva de poblaciones naturales de Helianthemum apenninum y H. caput-felis en Mallorca ha demostrado que son básicamente entomófilos, aunque también producen numerosos frutos por auto-polinización. Las flores de H. caput-felis duran cuatro dias, mientras que las de H.apenninum duran uno, como suele ocurrir en otras especies del género. En la población de H. apenninum, la predación por ungulados afecta al 50% de los individuos. Los test de germinación mostraron una temperatura óptima de germinación de 16 ºC para H. apenninum y de 23ºC para H. caput-felis. H. caput-felis muestra una importante variabilidad interanual en su comportamiento germinativo. En las poblaciones naturales de H. caput-felis, se ha observado atelecoria, y en relación con ésta, las semillas germinan dentro de la cápsula

Tourism and hospitality sector electricity use: evidences from 12 EU countries

At the Paris Conference of the Parties (COP21) in 2015, 195 countries agreed to strengthen the global response to the threat of climate change. Along this line, the EU is committed to a 40% reduction in their domestic greenhouse gas emissions by 2030. This new target represents a significant progression beyond its existing 20% emission reduction commitment by 2020. Thus, greater efforts will be needed affecting all productive sectors in order to reduce CO2 emissions and energy consumption. In order to reach this ambitious target, new measures affecting all economic sectors would be needed. This paper focuses on the tourism sector. This aim of this study is to investigate the relationships between tourist overnight stays and the hospitality sector electricity consumption. These relationships are studied for 12 EU countries during the period 2005-2012, accordingly with the available data. With this aim, econometric panel data techniques are used in order to estimate an electricity consumption function for the hospitality sector which depends on tourism, income, price and climate variables. The Environmental Kuznets Curve hypothesis is also tested. An Energy-tourism Kuznets Curve would show that increasing earnings from tourism will bring about reduced electricity consumption from a threshold point, which could be related to the fact that more earnings could imply undertaking more energy efficiency measures