Artículos - Ingeniería Electrónica y de Telecomunicaciones

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Robust voice activity detection algorithm using spectrum estimation and dynamic thresholding
(IEEE Computer Society, 2009) Zenteno Bolaños, Efrain; Sotomayor Polar, Manuel Gustavo
An algorithm for voice activity detection (VAD) is presented in this paper, it uses the classical short time fourier transform (STFT) followed by dynamic thresholding over the noise floor which allows accurate determination for voiced/unvoiced frame. This algorithm has also been implemented in a DSP plataform to evaluate its performance in real time, where results have shown that such method presents accurate voiced/unvoiced determination under unknown signal to noise ratio (SNR) conditions. © 2009 IEEE.
Fast analysis of cylindrical microstrip lines printed on substrates composed of multiple layers
(John Wiley and Sons Inc., 2010) Manuel Gustavo Sotomayor Polar; Thomas Heckler, Marcos Vinicio; Dreher, Achim
This letter presents an analysis of microstrip lines that are printed on substrates composed of numerous dielectric layers using a fast technique that comprises the full-wave equivalent circuit and the discrete mode matching method. The validation of the proposed formulation has been done with a commercial package based on the finite-element method and very good agreement has been obtained. As a special application of our technique, we consider the analysis of microstrip lines printed on substrates with dielectric constants that vary according to given graded-index profiles. The profiles are modelled by replacing the substrate by numerous homogeneous dielectric layers. © 2010 Wiley Periodicals, Inc.
Multiple split-ring resonators for tri-band filter with asymmetric response
(Scopus, 2011) Castillo Araníbar, Patricia Raquel; Garcia Lamperez, Alejandro; Segovia Vargas, Daniel; Salazar Palma, Magdalena; Barbin, Silvio
A triple-band filter composed of multiple split ring resonators is presented. This filter is based on a chain of triple split ring resonators that produces three pass-bands. The change in the dimensions of the corresponding meander lines of the tri-band SRRs can make us obtain an asymmetric response. This response is useful for some microwave applications. This paper presents a study of asymmetric multiband filters based on multiple split ring resonators. © 2011 IEEE.
Design of a compact diplexer for multisystem das solutions
(IEEE Computer Society, 2011) Castillo Araníbar, Patricia Raquel; Garcia Lamperez, Alejandro; Segovia Vargas, Daniel; Salazar Palma, Magdalena
This paper presents a microstrip diplexer for multisystem Distributed Antenna System (DAS) solutions, namely for DCS and UMTS systems. A low-pass quasi-elliptic filter with a stub-like structure is used for the 1800 MHz band while a band-pass Chebychev filter with a hairpin line structure is employed for the 2150 MHz band. Both filters are connected to the common port through a T junction. The diplexer layout has been optimized in order to ensure compactness. Good agreement between simulated and measured results has been obtained. The diplexer shows excellent performance in terms of high isolation and low insertion loss. A semi-lumped element model of the diplexer is also presented. © 2011 IEEE.
2-STCg optical multicast traffic grooming node for the fishbone-like Peruvian WDM core network
(IEEE Computer Society, 2011) Nereida, Llerena; Fernández Del Carpio, Gonzalo
In some developing countries, like Peru, optical transport networks are not widely deployed, mainly because of economical factors and geographical difficulties. Its topology has a fishbone-like structure, and it may not need powerful all-optical multicast nodes in order to attend multicast demands. Also, traffic demands may not occupy all the wavelength capacities, which make traffic grooming a necessary capability for saving bandwidth. In the present work we propose an optical node capable of performing multicast routing tasks at traffic grooming level. The node's architecture has been based on two previous works: the 2-Split-Tap-and-Continue (2-STC) node (a multicast capable node with a simple structure, constrained to binary-splitting, but efficient regarding the use of power levels and the number of elements used), and the Stop-and-Go (S/G) Light Tree node (a multicast grooming capable node that uses a labeling technique based on FSK modulation, allowing multicast requests to be routed at the optical level). In this sense, the proposed node improves the use of the optical power, waste of bandwidth and delay, taking advantage of the physical distribution presented in this particular fishbone-like network. Several simulations have been done and results show these assessments. © 2011 IEEE.
Real adaboost with gate controlled fusion
(Scopus, 2012) Mayhua López, Efraín Tito; Gómez Verdejo, Vanessa; Figueiras-Vidal, Anibal
In this brief, we propose to increase the capabilities of standard real AdaBoost (RAB) architectures by replacing their linear combinations with a fusion controlled by a gate with fixed kernels. Experimental results in a series of well-known benchmark problems support the effectiveness of this approach in improving classification performance. Although the need for cross-validation processes obviously leads to higher training requirements and more computational effort, the operation load is never much higher; in many cases it is even lower than that of competitive RAB schemes. © 2012 IEEE.
Design of an array based on an antipodal balanced Vivaldi antenna
(Scopus, 2012) Talavera Ormeno, Chris Kathleen; Molina Alvarez, Martha Maria; Choquehuanca Zevallos, Juan José; Javashvili, Otar
Due to the many breakthroughs in the field of based pulse radars and ultra wide bandwidth (UWB) systems, researches of every component of those systems have been performed in recent years. As well as, in order to match the great bandwidth that pulse-based radar needs to optimally work, UWB antennas were developed for this purpose. In this paper an array based on an antipodal balanced Vivaldi antenna is studied by simulating firstly a unique Vivaldi antenna element and analyzing its return loss, gain, etc. Then a five element antenna array was built in the HFSS simulator. The gain, as it was expected, has been increased to be closed to 16 dBi and maintaining the good S11 performance of one single Vivaldi antenna. © 2012 IEEE.
An autonomous robot based on a Wheelchair
(Scopus, 2012) Gonzales, Raul; Gaona, Federico; Peralta, Raul
This paper presents the design and implementation of an Autonomous Movement Robot based on a Wheelchair. The target coordinates of the destination place are pre-established in the processing unit of the robot and it uses a GPS system and sensors in order to get its final destination and to avoid obstacles in its path respectively. The contribution of this work is the combination of several technologies and techniques that came from different areas such as mechanical, electronic and computer engineering. © 2012 IEEE.
Depth-wise multi-protocol stateless switching of multicast traffic
(Scopus, 2012) Fernández Del Carpio, Gonzalo; Larrabeiti, David
In order to reduce the state due to multicast forwarding in packet switched networks a number of proposals have been studied in the literature. One recently studied approach is MPSS (Multi-Protocol Stateless Switching), in which the path (unicast) or the tree (multicast) is encoded as a Bloom filter carried by a packet header. This sort of source-routed forwarding method makes it possible to eliminate the forwarding state in network nodes. Our proposal looks into improving MPSS and at the same time solving the forwarding anomalies observed in multicast Bloom filter-based approaches. We propose to encode the multicast tree into a stack of variable-length Bloom filters representing the set of output interfaces at a given tree depth, instead of a single filter for the whole tree. We prove that our approach is more efficient than MPSS on multicast, especially in large networks, and that it reduces and binds the scope of forwarding anomalies derived from false positives: packet storms, forwarding loops and flow duplication. Furthermore, packet processing is simpler and the average header overhead is reduced. © 2012 IEEE.
A study on residents willingness to pay for personal carbon trading and relevant factors
(CUPUM, 2013) Zhou, Kui; Jia, San; Kondo, Akio; Konbdo, Akiko; Cartagena Gordillo, Alex
Un estudio sobre la disposición de los residentes a pagar por el comercio de carbono personal y los factores relevantes
Compact triplexer with open ring resonators as microstrip trisection bandpass filters for asymmetric response
(Scopus, 2013) Castillo Araníbar, Patricia Raquel; Rodriguez Postigo, Paolo Alexander; Garcia Lamperez, Alejandro; Segovia Vargas, Daniel
Open loop ring resonators are used as the basic block of a compact planar triplexer, they are used in cascaded trisection (CT) filters, in order to reduce the circuit size. The CT filter has a cross coupling that produces a single attenuation pole at finite frequency used to shape the bandpass response. Ring resonators are properly located with respect to the input and output feed lines, in order to get good isolation response, and also to suppress channel interfering and to meet the design specifications for applications in mobile communication. The triplexer was fabricated and measured to verify the viability of the design with good agreements between the measurements and the simulations. © 2013 IEEE.
NMF-based temporal feature integration for acoustic event classification
(International Speech and Communication Association, 2013) Ludeña Choez, Jimmy Diestin; Gallardo Antolín, Ascensión
In this paper, we propose a new front-end for Acoustic Event Classification tasks (AEC) based on the combination of the temporal feature integration technique called Filter Bank Coefficients (FC) and Non-Negative Matrix Factorization (NMF). FC aims to capture the dynamic structure in the short-term features by means of the summarization of the periodogram of each short-term feature dimension in several frequency bands using a predefined filter bank. As the commonly used filter bank has been devised for other tasks (such as music genre classification), it can be suboptimal for AEC. In order to overcome this drawback, we propose an unsupervised method based on NMF for learning the filters which collect the most relevant temporal information in the short-time features for AEC. The experiments show that the features obtained with this method achieve significant improvements in the classification performance of a Support Vector Machine (SVM) based AEC system in comparison with the baseline FC features. Copyright © 2013 ISCA.
NMF-Based Spectral Analysis for Acoustic Event Classification Tasks
(Scopus, 2013) Ludeña Choez, Jimmy Diestin; Gallardo Antolín, Ascensión
In this paper, we propose a new front-end for Acoustic Event Classification tasks (AEC). First, we study the spectral contents of different acoustic events by applying Non-Negative Matrix Factorization (NMF) on their spectral magnitude and compare them with the structure of speech spectra. Second, from the findings of this study, we propose a new parameterization for AEC, which is an extension of the conventional Mel Frequency Cepstrum Coefficients (MFCC) and is based on the high pass filtering of acoustic event spectra. Also, the influence of different frequency scales on the classification rate of the whole system is studied. The evaluation of the proposed features for AEC shows that relative error reductions about 12% at segment level and about 11% at target event level with respect to the conventional MFCC are achieved. © 2013 Springer-Verlag Berlin Heidelberg.
Design and simulation of triplexer for mobile communications using trisection resonators filters
(Scopus, 2013) Rodriguez Postigo, Paolo Alexander; Castillo Araníbar, Patricia Raquel
This paper presents a microstrip triplexer with multiband performances by using cascaded trisection (CT) filters. Each CT section is composed by three directly coupled resonators with a cross coupling. The cross coupling produces a single attenuation pole at the finite frequency. Furthermore, each trisection filter controls a specific channel frequency independently. To obtain good isolation response, the resonators are properly located with respect to the input and output feeding lines to suppress the channel interfering and meet the design specifications for mobile communications. © 2013 IEEE.
Modeling the frequency dispersion phenomena in GaN and GaAs devices for broadband data communication
(Institute of Electrical and Electronics Engineers Inc., 2014) Rafael Valdivia, Guillermo; Su, Zhiguo; Urquizo, Anthony; Mendoza, Thalia
A novel technique for modeling GaN and GaAs transistors for data communications is proposed. The technique can model one of the most critical phenomena in wideband communications, called frequency dispersion effects. Results of measurements reveal the accuracy of this model under small and large signal conditions. © 2014 IEEE.
Feature extraction based on the high-pass filtering of audio signals for Acoustic Event Classification
(Academic Press, 2015) Ludeña Choez, Jimmy; Gallardo Antolín, Ascensión
In this paper, we propose a new front-end for Acoustic Event Classification tasks (AEC). First, we study the spectral characteristics of different acoustic events in comparison with the structure of speech spectra. Second, from the findings of this study, we propose a new parameterization for AEC, which is an extension of the conventional Mel-Frequency Cepstral Coefficients (MFCC) and is based on the high pass filtering of the acoustic event signal. The proposed front-end have been tested in clean and noisy conditions and compared to the conventional MFCC in an AEC task. Results support the fact that the high pass filtering of the audio signal is, in general terms, beneficial for the system, showing that the removal of frequencies below 100-275 Hz in the feature extraction process in clean conditions and below 400-500 Hz in noisy conditions, improves significantly the performance of the system with respect to the baseline. © 2014 Elsevier Ltd. All rights reserved.
Preface
(CEUR-WS, 2015) Fernández Del Carpio, Gonzalo
Actas del taller CEUR
Nonlinear device model for GaN and GaAs microwave transistors including memory effects
(Institute of Electrical and Electronics Engineers Inc., 2015) Rafael Valdivia, Guillermo; Urquizo, Anthony; Mendoza, Thalia; Barbin, Silvio
In this paper, a new technique for modeling GaN and GaAs transistors is presented. The technique can model one of the most critical phenomena in telecommunications, frequency dispersion effects which is related to memory effects. Results of measurements reveal the accuracy of this technique under small-signal and large-signal conditions. The proposed technique can be embedded into other models to improve its capabilities using only one current source in a new large signal equivalent circuit. © 2015 IEEE.
Implementation of stateless routing mechanisms for multicast traffic on NetFPGA card
(Institute of Electrical and Electronics Engineers Inc., 2015) Martínez Aguilar, Roberto B.; Fernández Del Carpio, Gonzalo
Recent researches have studied how to support the online distribution of multimedia contents efficiently, reducing almost completely the state information within switching nodes. However, many of these studies have been carried out only in a theoretical way and have been verified by simulations, without actual hardware implementations, which will reveal their true performance. One of the main proposals consists on changing the current paradigm in transport networks, by encoding the path information into packet headers using Bloom filters to virtually eliminate the routing tables. In this paper we work on the implementation of a node in a NetFPGA card to evaluate the performance of MPSS and D-MPSS mechanisms (proposed in previous works), which use Bloom filters into the packet headers. To build this, it is required to develop some techniques to work with header Bloom filters of variable size, which need compression and decompression in the fastest possible way, optimizing the resources used during the switching decisions. Performance measurements are provided to verify the forwarding efficiency, considering latencies and the comparison between both methods, in which an advantage for D-MPSS is checked. © 2015 IEEE.
LTE radio and network planning: Basic coverage and interference constraints
(Institute of Electrical and Electronics Engineers Inc., 2016) Velez, Fernando; Robalo, Daniel; Acevedo Flores, Jessica
In the cellular planning process, the UL and DL the values from carrier-to-noise-plus-interference ratio (CNIR) from/at the mobile station are very important parameters. From a detailed analysis of its variation with the coverage and reuse distances for different values of the Chanel Quality Indicator (CQI) and given empirical propagation models, an evaluation of the possible range for the reuse pattern is performed for the DL. By considering the CQI and reference CNIR requirements recommended by 3GPP, DL peak bit rates along with the Transport Block Size (TBS) assumed for single stream and bandwidth of 5 MHz, physical and supported throughputs are analysed. These formulations shows the clear decrease of the supported throughput for the longest coverage distances in the LTE 2.6 GHz band, a behaviour that is not so clear at 800 MHz, and gives useful indications to the optimization of the use of different frequency bands in the optimization of carrier aggregation between two different bands in LTE-A scenarios. © 2015 IEEE.

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