937 research outputs found
Experimental study of MIMO-OFDM transmissions at 94 GHz in indoor environments
Millimeter wave (mm-wave) frequencies have been proposed to achieve high capacity in 5G communications. Although meaningful research on the channel characteristics has been performed in the 28, 38and 60 GHz bands ─in both indoor and short-range scenarios─,only a small number of trials (experiments) have been carried out in other mm-wave bands. The objective of this work is to study the viability and evaluate the performance of the 94 GHz frequency band for MIMO-OFDM transmission in an indoor environment. Starting from a measurement campaign, the performance of MIMO algorithms is studied in terms of throughput for four different antenna configurations.This work was supported in part by the Ministerio de Economía y Competitividad MINECO, Spain under Grant TEC2016-78028-C3-2-P, and in part by the European FEDER funds
Performance of likelihood ratios considering bounds on the probability of observing misleading evidence
This is a pre-copyedited, author-produced version of an article accepted for publication in Law, Probability & Risk following peer review. The version of record Jose Juan Lucena-Molina, Daniel Ramos-Castro, Joaquin Gonzalez-Rodriguez; Performance of likelihood ratios considering bounds on the probability of observing misleading evidence. Law, Probability and Risk 2015; 14 (3): 175-192 is available online at: http://dx.doi.org/10.1093/lpr/mgu022In this article, we introduce a new tool, namely 'Limit Tippett Plots', to assess the performance of likelihood ratios in evidence evaluation including theoretical bounds on the probability of observing misleading evidence. To do that, we first review previous work about such bounds. Then we derive 'Limit Tippett Plots' that complements Tippett plots with information about the limits on the probability of observing misleading evidence, which are taken as a reference. Thus, a much richer way to measure performance of likelihood ratios is given. Finally, we present an experimental example in forensic automatic speaker recognition following the protocols of the Acoustics Laboratory of Guardia Civil, where it can be seen that 'Limit Tippett Plots' help to detect problems in the calculation of likelihood ratios
Traffic noise mitigation using single and double barrier caps of different shapes for an extended frequency range
The primary function of noise barriers is to shield inhabitants of affected areas from excessive noise generated by road traffic. To enhance the performance of noise barriers while simultaneously adhering to height restrictions, the attachment of structures (caps) of different shapes to the tops of conventional screens can be considered. These caps can significantly impact the diffracted sound energy, thereby increasing the desired global acoustic losses. This work presents a comprehensive study of the acoustic performance of noise barriers with single and double attached caps of different shapes through a calculation of their insertion losses (IL). This study comprehensively addresses and compares different types, sizes, combinations, and numbers of noise barrier caps for different scenarios (including sloping and absorbent grounds) and sources (“car” and “ambulance”) for an extended frequency band up to 10 kHz. To the best of the authors’ knowledge, this is a range that has not previously been analyzed. A variety of different cap shapes were considered including cylinders, rectangles, trapezoids, and Y/T-shaped forms. To calculate the IL, an innovative and fast uniform theory of diffraction (UTD)-based method developed by the authors was applied in all simulations. The results showed that the Y-shaped single and double barrier caps were, in general, the most effective at increasing IL without raising the height of the barrier, thereby successfully managing the aesthetic impact. The results also showed how the consideration of sloping and absorbent floors could also contribute to improved noise abatement.This work was funded by the Ministerio de Ciencia e Innovación, Spain (TEC2016-78028-C3-2-P and PID2019-107885GB-C33), and by the European Fonds Européen de Développement Économique et Régional (FEDER) funds
Una función de atenuación expresada en términos de coeficientes UTD para la difracción múltiple de ondas esféricas en comunicaciones microcelulares
This work presents an explicit formulation for multiple
edge diffraction for mobile radiowave propagation in
terms of UTD-diffraction coefficients when a spherical
incident wave is considered. The solution sharply reduces
the computing time over existing formulation, specially
when the number of edges is very large. The applicability
of the result is interesting for both area coverage and
interference predictions in microcellular systems.Los autores agradecen a la Dirección General de Ciencia,
Tecnología y Sociedad de la Información (Consejería de
Ciencia, Tecnología, Industria y Comercio de la Comunidad
Autónoma de la Región de Murcia) la financiación de este
trabajo (2I02SIU0019)
Medidas del canal MIMO en la transición de entrada a un pequeño tunel
This contribution investigates the MIMO
channel by means of measurements at the entrance of a
small tunnel at 2.4 GHz. The wireless channel is
measured within 100MHz for a 4x4 MIMO system. It
focuses on variations of the transmitter offset and on
different antenna spacings, in order to understand the
impact of different configurations on capacity. It will be
shown that capacity is sensitive to the transmitter offset.
Indeed, these measurements showed than it is possible to
maintain a low distance between antenna elements if the
transmitting offset is increased.Los autores agradecen al Ministerio de Educación y
Ciencia (TEC2004-04866-C04-04/TCM) y a la Fundación
Séneca (PPC/01444/03) por financiar este trabajo
Una solución híbrida UTD-PO para el análisis de la difracción múltiple de una serie de cilindros asumiendo incidencia de onda esférica
A new hybrid uniform theory of diffraction-physical
optics (UTD-PO) formulation for the analysis of the multiple
diffraction caused by an array of cylinders, assuming sphericalwave
incidence, is hereby presented. The solution, validated
with numerical data from technical literature, is mathematically
less complex and computationally more efficient −for a large
number of cylinders− than other existing methods, due to the
fact that high-order diffraction terms (slope diffraction) are not
considered, without such lack of terms barely entailing any loss
in accuracy. Results can be applied in radiowave propagation
analysis when multiple diffraction over rounded obstacles has to
be considered.Los autores agradecen al Ministerio de Educación y
Ciencia (TEC2007-66698-C04-04/TCM) y a la Fundación
Séneca de Murcia (03133/PI/05) la financiación de este
trabajo
Bosentan and oral anticoagulants in HIV patients: what we can learn of cases reported so far
Pulmonary arterial hypertension is an infrequent but nevertheless serious life-threatening severe complication of HIV infection. It can be treated with bosentan and oral anticoagulants. Bosentan could induce the acenocoumarol metabolism and it increases the INR values. Until now, no study of interaction between bosentan and oral anticoagulants in HIV patients has reported. So we present a case of this interaction between these drugs and we reviewed MEDLINE to identify all the papers published so far. In our case, several weeks after increasing dose of bosentan acenocoumarol dose had to be progressively increased to 70 mg/week (+33%) without obtaining an adequate INR level (2.0–3.0). Forty-nine days later, we achieved a therapeutic INR with 90 mg/week of warfarin. The use of bosentan and oral anticoagulants together in these patients require a closer monitoring during first weeks of treatment, after increasing the bosentan dose and even during longer periods of time
Aplicación de los sistemas de información geográfica a la planificación de sistemas de radiocomunicación
Los Sistemas de Información Geográfica (SIG) se han utilizado tradicionalmente en problemas territoriales que requieren el manejo de gran volumen de información donde la componente espacial juega un papel importante. De la misma manera, la planificación de los sistemas de radiocomunicación es un problema espacial que es posible gestionar eficientemente mediante aplicaciones basadas en SIG como pone de manifiesto este artículoEl desarrollo de la herramienta RAGIS ha recibido ayuda en convocatoria pública por parte de la Consejería de Ciencia, Tecnología, Industria y Comercio de la Comunidad Autónoma de la Región de Murcia (Ref. 2I02SIU0019) y ha colaborado en el proyecto empresa EMURTEL SA.Escuela Técnica Superior de Ingeniería de Telecomunicació
Influencia del modelado de edificios en la predicción de pérdidas por difracción múltiple en entornos urbanos
A study of the influence of building modeling
when predicting the signal attenuation due to overrooftop
multiple diffraction in urban environments is
presented. A straightforward formulation expressed in
terms of Uniform Theory of Diffraction (UTD)
coefficients is used for the above-mentioned analysis
assuming a spherical-wave incidence over the array of
buildings and considering the latter modeled as series of
different representations such as knife edges, double
knife edges, wedges and rectangular sections. The results
clearly indicate the importance of an appropriate
building modeling in obtaining realistic path-loss
predictions in urban environments when multiple
diffraction has to be considered
Precios y salarios en Jaén en 1627. Pragmatica de Felipe IV
Los abundantes excedentes producidos durante casi todo el siglo XVI y comienzos del siglo XVII por las buenas cosechas cerealistas, oleícolas, vitivinícolas y otros productos de huerta que con gran regularidad ofrecieron las tierras jiennenses, así como las selectas lanas, pieles y carnes proporcionadas por la numerosa y pujante ganadería apacentada en los barbechos, baldíos, dehesas y montes del Alto Guadalquivir, posibilitaron y fomentaron un
activo comercio comarcal, regional y exterior tanto en la oferta de una rica y
variada gama de productos como en la demanda no sólo de los propios, sino de los que en gran variedad y cantidad llegaban de tierras exteriores, lejanas o cercanas, al Reino de Jaén.
Este vivo intercambio comercial desarrollado en las numerosas tiendas y talleres de las ciudades, en mercados semanales y en ferias anuales promocionó una febril actividad laboral agroganadera y artesanal y unas posibilidades, jamás constatadas hasta este momento, de oferta y demanda de productos agrarios y artesanales.Departamento de Historia Moderna y de América, Universidad de Granada
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