3,823 research outputs found
Ley #153 de telecomunicaciones
José R. Cruz Campillo (biografía): Abogado dominicano, egresado de la Universidad Nacional Pedro Henríquez Ureña (UNPHU). Realizó un posgrado en derecho e instituciones legales estadounidenses en la Universidad de Wisconsin. Es socio fundador de Jiménez-Cruz-Peña Abogados. Previamente había ocupado diversas posiciones en la Compañía Dominicana de Teléfonos. En su práctica profesional se ha especializado en derecho corporativo, inversión extranjera, propiedad intelectual y telecomunicaciones.He aquí la presentación del que por entonces era el anteproyecto de la nueva Ley General de Telecomunicaciones en República Dominicana, pieza legislativa en cuya elaboración se contó con la cooperación del Programa de las Naciones Unidas para el Desarrollo (PNUD) y la Unión Internacional de Telecomunicaciones (UIT). A juicio del autor, este nuevo marco regulativo fue el resultado de la aplicación doméstica de las reglas generales de comercio para el sector establecidas en los acuerdos mundiales del GATT/94, reglas que permitían una respuesta institucional efectiva al crecimiento y diversificación de un sector central del siglo XXI
A 10-way power divider based on a transducer and a radial junction operating in the circular TM01 mode
This work presents a 10-way Ku-band power divider using a mode transducer and a radial junction connected by an overmoded circular waveguide operating in the TM 01 mode. The circular symmetry of this mode has been exploited to obtain a power divider with the rectangular output ports radially distributed along the broad wall of the waveguides in H-plane configuration. This topology provides the same amplitude and phase for all the output ports. At the same time, a compact profile has been obtained, introducing a simple manufacturing for the two components of the divider. The first component is a mode transducer converting the TE 10 mode in the rectangular waveguide to the TM 01 mode in the circular waveguide. It is based on a novel topology providing a very high purity in the mode conversion with an attenuation for the other propagating mode, the TE 11c , higher than 60 dB. The second component is a 10-way radial junction that must work under the excitation of the TM 01 , whose special features, since this mode is not the fundamental one of the circular waveguide, will be highlighted. The final design has been validated with an experimental prototype, proposing a manufacturing based on four simple parts. This has been the key to obtain an experimental prototype with specifications in the state-of-the-art. The measured efficiency is better than 96.5% in a 16.7% relative frequency bandwidth from 11 GHz to 13 GHz, with return losses better than 25 dB in the common port. The measured difference between the signals at the output ports of the prototype is ±0.3 dB for the amplitudes and ±0.45° for the phases. A comparison of the obtained results with another divider based on the TE 01 mode shows the potential of the presented design for becoming an alternative to the more extended TE 01 -based power dividersThis work was supported by the Spanish Government through the Agencia Estatal de Investigacion, Fondo Europeo de Desarrollo Regional
(AEI/FEDER, UE), under Grant TEC2016-76070-C3-1/2-R (ADDMATE
Development of a high-performance W-band duplexer for plasma diagnosis using a single band with dual circular polarization
Discrepancia entre la información que aparece en el artículo que indica que el copyright es de Elsevier, y la información que aparece en la página de la revista y en el Copyright Clearance Center que indican © 2019 The Authors. Published by Elsevier B.V., así como que el artículo está publicado en Open Access under a Creative Commons licenceThis work presents the design and experimental validation of a high performance, compact, waveguide duplexer operating from 91.5 to 96.5 GHz for its integration in diverse W-band microwave equipment as in plasma diagnosis applications. It uses a single frequency band, with two signals discriminated by different orthogonal circular polarization, which is generated by means of a septum orthomode transducer (OMT) polarizer. Moreover, this component is optimized loaded with the horn antenna for improving the overall system performance. It is explained how these two components are integrated into a very compact duplexer, designed using efficient numerical algorithms. The manufacturing process by mean of high precision milling, and including electrical discharge machining (EDM) has led to excellent performances. The measured return loss level and isolation are higher than 30 dB, and the insertion loss level is below 0.3 dB. Finally, the key parameter in this device, which reflects the symmetry in the manufacturing process, i.e., the axial ratio, is lower than 0.6 dB for both polarizations, an excellent result showing the potential of the presented designThis work was supported by the Spanish government under grants (ADDMATE) TEC2016-76070-C3-1/2-R (Agencia Estatal de Investigación, Spain, Fondo Europeo de Desarrollo Regional: AEI/FEDER/UE) and the program of Comunidad de Madrid, Spain S2013/ICE-3000 (SPADERADARCM
High-performance 16-way Ku-band radial power combiner based on the TE01-circular waveguide mode
This work presents a 16-way Ku-band radial power combiner for high power and high frequency
applications, using the very low loss TE01 circular waveguide mode. The accomplished design shows
an excellent performance: the experimental prototype has a return loss better than 30 dB, with a balance
for the amplitudes of ( 0.15 dB) and ( 2.5 ) for the phases, in a 16.7% fractional bandwidth (2 GHz
centered at 12 GHz). For obtaining these outstanding specifications, required, for instance, in highfrequency
amplification or on plasma systems, a rigorous step-by-step procedure is presented. First, a
high-purity mode transducer has been designed, from the TE10 mode in the rectangular waveguide to
the TE01 mode in the circularwaveguide, with very high attenuation (>50 dB) for the other propagating
and evanescent modes in the circularwaveguide. This transducer has been manufactured and measured
in a back-to-back configuration, validating the design process. Second, an E-plane 16-way radial
power divider has been designed, where the power is coupled from the 16 non-reduced-height radial
standardwaveguides into the TE01 circularwaveguide mode, improving the insertion loss response and
removing the usual tapered transformers of previous designs limiting the power handling. Finally, both
the transducer and the divider have been assembled to make the final radial combiner. The prototype
has been carefully manufactured, showing very good agreement between the measurements and the
full-wave simulationsThe authors would like to thank INMEPRE S.A., the diligence
in the manufacturing process. This work was supported
by the Spanish government under Grant (ADDMATE) No.
TEC2016-76070-C3-1/2-R (AEI/FEDER/UE) and the program
of Comunidad de Madrid S2013/ICE-3000 (SPADERADARCM
Static circularly symmetric perfect fluid solutions with an exterior BTZ metric
In this work we study static perfect fluid stars in 2+1 dimensions with an
exterior BTZ spacetime. We found the general expression for the metric
coefficients as a function of the density and pressure of the fluid. We found
the conditions to have regularity at the origin throughout the analysis of a
set of linearly independent invariants. We also obtain an exact solution of the
Einstein equations, with the corresponding equation of state , which
is regular at the origin.Comment: 10 pages, 1 figure, revtex 4. This paper is in honor of Alberto
Garcia's sixtieth birthday. Accepted by Gen. Rel. Gra
Assessing the embedded length of epoxy-bonded carbon laminates by pull-out bending tests
To evaluate the embedded length of epoxy-bonded fibre carbon laminates into concrete, pull-out bending tests were carried out. The laminates were embedded into concrete in order to prevent the phe-nomenon of peeling and to add extra protection against fire, therefore mobilising the potential of reinforce-ment of this composite material, with high tensile strength and stiffness. The bond-slip relationship obtained at the concrete-laminate interface can be used to define the corresponding constitutive law. This work de-scribes the tests that were performed, and discusses the results obtained in the preliminary experimental pro-gram carried out
Automatic neural generalized font identification
The final publication is available at Springer via http://dx.doi.org/10.1007/978-1-4471-1599-1_116Proceedings of the 8th International Conference on Artificial Neural Networks, Skövde, Sweden, 2–4 September 1998Neural methods are gaining a steady acceptance as powerful tools in a variety of pattern detection problems, OCR certainly being one of them. The concrete implementation of these neural OCR systems is of course a well guarded corporate secret, but in broad terms it can be said that in most of the cases, multilayer perceptrons (MLPs) are used. There are several reasons for the MLPs’ success. To begin with, they are based in well understood mathematical and statistical principles and there are efficient tools and methodologies for their training and evaluation. Furthermore they have good generalization properties.With partial support of grant TIC 95-965 of Spain's CICy
Fibrous model for the simulation of the cyclic behaviour of 3D reinforced concrete frames
Relatório 07-DEC/E-04Non-linear finite element analysis has attracted a lot of attention in last few decades, as
real life problems dealing with analysis of concrete beams and columns are generally
non-linear in nature. This project deals with non-linear analysis of beam and columns,
using Timoshenko beam theory. The Timoshenko beam theory is applied to every
element, but before applying the theory the element is divided into fibers. The fibers as a
whole will govern the behavior of element. The section of each element is divided in
“finite elements”. Each finite element is a fiber along the length of element. Each fiber
element is independent in terms of the material constitutive laws, which govern the
behavior, while at the same time they are associated to each other by the relation of
displacements. The material laws of each fiber deals with the stress-strain relation
The numerical results are compared with the experimental results, which show a
reasonable correlation, and in turn demonstrate the capability of the proposed model to
depict the cyclic behavior of concrete elements
Numerical model for CFRP confined concrete elements subject to monotonic and cyclic loadings
Uniaxial cyclic and monotonic compression tests were carried out on partially and fully wrapped concrete
cylinders with Carbon Fibre Reinforced Polymer (CFRP) wet lay-up sheets. The influence of the concrete
compressive strength, CFRP stiffness, geometric confinement arrangement and loading type on the
compressive behaviour of reinforced concrete column elements of circular cross section up to their failure
was assessed. A uniaxial stress-strain constitutive model is proposed, and the results obtained from the
experimental tests were used to calibrate some of the parameters of this model, and to appraise the model
performance. This model allows the simulation of reinforced concrete members by using Timoshenko
one-dimensional elements, in the context of the finite element method (fibre model). Good agreement was
obtained between numerical simulations and experimental results for both monotonic and cyclic loading
tests.The first author acknowledges the support provided by the grant within the ambit of the research program PABERPRO supported by Program POCI 2010 - IDEIA, Project No. 13-05-04-FDR-00007, contract reference ADI/2007/V4.1/0049. The present work was also supported by Program PIDDAC, Project No. PTDC/ECM/74337/2006 by FCT. The authors acknowledge the materials generously supplied by S&P and Degussa Portugal
Design-curves of strain softening and strain hardening fibre reinforced concrete elements subjected to axial load and bending moments
Several structural components made by fibre reinforced concrete (FRC) are submitted to axial load and bending moments. In some cases fibres cannot replace completely the conventional reinforcement, even if strain hardening FRC is used; therefore the optimization of the reinforcement solution for these elements depends on the post-cracking behaviour of the FRC, as well as the percentage of conventional reinforcement to replace. To fully exploit the FRC capabilities, the development of a suitable, comprehensive and design-oriented model of its tensile response is of the utmost importance. To provide a practical tool for the pre-design of FRC-structural-elements subjected to axial load and bending moments, design curves were generated using a computational program capable of simulating the main features of the tensile and compressive behaviour of strain softening and strain hardening FRC’s, and steel bars. The post-cracking tensile behaviour of the FRC is characterized by two parameters that define its residual strength ratio (α) and its corresponding tensile strain ratio (β). To generate these curves, a parametric study is carried out based on the tensile parameters α and β and considering distinct mechanical reinforcement ratios, from 0 to 1 with a step of 0.2. For every reinforcement ratio, four distinct cases in terms of β are considered; additionally, for every case of β, α is divided from strain hardening to strain softening in five distinct residual strength classes. By sequentially varying α and β, the bending capacity of a section is evaluated to provide a design perspective of the effect of ductility and strength. The model used in this study is described, the design curves are presented and analyzed and some practical design examples are provided
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