2,038 research outputs found
On the Utility of the Inverse Gamma Distribution in Modeling Composite Fading Channels
We introduce a general approach to characterize composite fading models based on inverse gamma (IG) shadowing. We first determine to what extent the IG distribution is an adequate choice for modeling shadow fading, by means of a comprehensive test with field measurements and other distributions conventionally used for this purpose. Then, we prove that the probability density function and cumulative density function of any IG-based composite fading model are directly expressed in terms of a Laplace-domain statistic of the underlying fast fading model, and in some relevant cases, as a mixture of well-known state-of-the-art distributions. We exemplify our approach by presenting a composite IG/two-wave with diffuse power fading model, for which its statistical characterization is directly attained in a simple form.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Performance analysis of MIMO-OFDM systems using complex Gaussian quadratic forms
En este trabajo se proponen aportaciones originales para el análisis de prestaciones en sistemas multiantena con múltiples portadoras, mediante el desarrollo de nuevas técnicas matemáticas para el cálculo de probabilidades de error. Así, ha sido posible analizar el efecto de no idealidades (estimación de canal imperfecta, offset de continua, desbalanceo I/Q…) en las prestaciones de sistemas de comunicaciones móviles e inalámbricas
Are Floods Becoming a More Expensive Hazard? A Damages Review of the Southeastern Spanish Coast (1996–2016).
Over the last few decades, an increasing economic and social flooding damages trend has been recorded worldwide. Although this situation was initially associated with climate change, recently different institutions and scientific papers have related this trend to two main reasons: (i) a human population increase and (ii) the number of assets located in floodable areas. In this regard, this paper analyses evolutions in flood damages and their causes in a Mediterranean area, the provinces of Alicante and Murcia, between 1996 and 2016. The duration of this period, from a flood risk management policy point of view, is very important because it encompasses one of the most important legislative periods at a national and European level. As a main result, this paper establishes a temporal and spatial pattern related to increases in flood damages and their main influence on coastal areas, respectively, due to certain economic, spatial and temporal factors. As a conclusion, these trends demonstrate the inefficiency of flood risk management policies, especially those connected with spatial planning.Partial funding for open access charge: Universidad de Málag
Assessing habitat diversity and potential areas of similarity across protected areas globally
Biophysical characterization analyses of protected areas (PA) that provide information on their ecological values
and potential areas with similar characteristics are needed to make informed PA network planning and management
decisions. This study combines and further develops methodologies that use remote sensing and
modelling to identify habitat functional types in PAs and map similar areas at the ecoregion level. The study also
develops new terrestrial habitat diversity and irreplaceability indices at habitat and PA scale that allow the
comparison and ranking of PAs in terms of biophysical gradients and singular environmental conditions. Six PAs
were selected to highlight and discuss the results of the proposed methodology. Both individual and composite
indices should be considered when trying to compare PAs to understand the overall complexity and ecological
values of each PA. Results can inform planning and management of individual and protected area networks as
well as identify new areas for conservation. The information provided by the model about similar habitats
outside protected areas can also help assess their representativeness and support studies to strengthen ecological
connectivity. Besides systematic comparisons, detailed assessments of protected areas can also be performed
using medium and high-resolution input variables. This is especially relevant for protected areas in developing
countries where undertaking fieldwork is very difficult and the budget devoted to conservation is limited.European Commission
European Commission Joint Research CentreBiodi- versity and Protected Areas Management (BIOPAMA) programme, an initiative of the African, Caribbean and Pacific (ACP) Group of StatesMarie Curie Actions CT-EX2020D381533-101Spanish Ministry of Universities and Next Generation European Union fund
Model ensembles of ecosystem services fill global certainty and capacity gaps
UK Research & Innovation (UKRI) NE/W005050/1
NE/T00391X/1
ES/R009279/1
ES/T007877/1
ES/V004077/1
ES/R006865/1National Science Foundation (NSF)
NSF - Office of the Director (OD) 08695Next Generation European Union fundsUKCEHSpanish Government
DGE-213989
Understanding the impact of line-of-sight in the ergodic spectral efficiency of cellular networks
In this paper we investigate the impact of lineof-sight (LoS) condition in the ergodic spectral efficiency of cellular networks. To achieve this goal, we have considered the kappa-mu shadowed model, which is a general model that provides an excellent fit to a wide set of propagation conditions. To overcome the mathematical complexity of the analysis, we have split the analysis between large and small-scale effects. Building on the proposed framework, we study a number of scenarios that range from heavily-fluctuating LoS to deterministic-LoS. Finally, we shed light on the interplay between fading severity and spectral efficiency by means of the amount of fading.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
A Formulation of the Log-Logistic Distribution for Fading Channel Modeling
In some scenarios, the log-logistic (LL) distribution is shown to provide the best fit to field
measurements in the context of wireless channel modeling. However, a fading channel model based
on the LL distribution has not been formulated yet. In this work, we introduce the L-distribution
as a reformulation of the LL distribution for channel modeling purposes. We provide closed-form
expressions for its PDF, CDF, and moments. Performance analysis of wireless communication systems
operating under L-fading channels is exemplified, providing exact and asymptotic expressions for
relevant metrics such as the outage probability and the average capacity. Finally, important practical
aspects related to the use of the L-distribution for channel fitting purposes are discussed in two
contexts: (i) millimeter-wave links with misaligned gain, and (ii) air–ground channels in unmanned
aerial vehicle communications.European Social and Regional FundsJunta de Andalucia P18-RT-3175
UMA20-FEDERJA-002Universidad de MalagaUniversidad de Granad
Characterization of TrxC, an Atypical Thioredoxin Exclusively Present in Cyanobacteria
Cyanobacteria form a diverse group of oxygenic photosynthetic prokaryotes considered to be the antecessor of plant chloroplast. They contain four different thioredoxins isoforms, three of them corresponding to m, x and y type present in plant chloroplast, while the fourth one (named TrxC) is exclusively found in cyanobacteria. TrxC has a modified active site (WCGLC) instead of the canonical (WCGPC) present in most thioredoxins. We have purified it and assayed its activity but surprisingly TrxC lacked all the classical activities, such as insulin precipitation or activation of the fructose-1,6-bisphosphatase. Mutants lacking trxC or over-expressing it were generated in the model cyanobacterium Synechocystis sp. PCC 6803 and their phenotypes have been analyzed. The ΔtrxC mutant grew at similar rates to WT in all conditions tested although it showed an increased carotenoid content especially under low carbon conditions. Overexpression strains showed reduced growth under the same conditions and accumulated lower amounts of carotenoids. They also showed lower oxygen evolution rates at high light but higher Fv’/Fm’ and Non-photochemical-quenching (NPQ) in dark adapted cells, suggesting a more oxidized plastoquinone pool. All these data suggest that TrxC might have a role in regulating photosynthetic adaptation to low carbon and/or high light conditions.España, MINECO BIO2016-75634-PJunta de Andalucía P12-BIO-1119 , BIO-28
La Expulsión de los jesuitas de Catalunya
L'expulsió dels jesuïtes dels dominis de Carles III a la primavera de 1767 va tenir a
Catalunya certes particularitats: retards en l'aplicació del decret a Barcelona, Cervera i
Manresa; dificultats en el trasllat dels jesuïtes catalans fins al noviciat deTarragona; pressions
als novicis per a forçar l'abandonament de l'ordre, i el destacat paper de l'intendent
Juan Felipe Castaños en la preparació de l'embarcament a Salou. Es detalla amb
precisió el nombre de jesuïtes catalans enviats a l'exili i es descriu la peripècia del seu
viatge, ja que l'arribada a Ferrara, destinació definitiva a Itàlia, només va esdevenir-se al
setembre de 1768,després d'un traumàtic pas per l'illa deCòrsega.Entre els exiliats catalans
es trobaven destacats erudits, comNuix i Perpinyà, Llampillas,Gallisà, Pla, Gustà i
Joan Francesc Masdeu, entre d'altres. El retorn dels exiliats catalans supervivents solament
va ser possible l'any 1815, després que PiusVII restaurés la Companyia.The expulsion and exile of the jesuits in Catalonia.
The expulsion of the Jesuits in the dominions of Charles III in the spring of 1767, had some peculiarities in Catalonia: delays in the application of the decree in cities like Barcelona, Cervera and Manresa, difficulties in the transfer of the Catalan Jesuits to the novitiate of Tarragona, pressures to force the abandonment of the order to
these youngmen, and the prominent role of Juan Felipe Castaños, the local governor,
in the preparations for the embarking in Salou. It specifies the number of Catalans
Jesuits exiled and it describes the difficulties of their journey, since their arrival
in Ferrara, the city of their final destination in Italy, takes place in September 1768,
after spending a hard time in the island of Corsica. Among the Catalans exiled were great scholars, like Nuix i Perpinyà, Llampillas, Gallisá, Pla, Gustá or Joan Francesc Masdeu. The return of the Catalan exiled who survived was only possible in 1815,
upon the restoration of the Society of Jesus by Pio VII
Detection of Communities within the Multibody System Dynamics Network and Analysis of Their Relations
Multibody system dynamics is already a well developed branch of theoretical, computational and applied mechanics. Thousands of documents can be found in any of the well-known scientific databases. In this work it is demonstrated that multibody system dynamics is built of many thematic communities. Using the Elsevier’s abstract and citation database SCOPUS, a massive amount of data is collected and analyzed with the use of the open source visualization tool Gephi. The information is represented as a large set of nodes with connections to study their graphical distribution and explore geometry and symmetries. A randomized radial symmetry is found in the graphical representation of the collected information. Furthermore, the concept of modularity is used to demonstrate that community structures are present in the field of multibody system dynamics. In particular, twenty-four different thematic communities have been identified. The scientific production of each community is analyzed, which allows to predict its growing rate in the next years. The journals and conference proceedings mainly used by the authors belonging to the community as well as the cooperation between them by country are also analyzed
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