Simple Method for Perfect Reconstruction QMF Filter Design

The purpose of this work is the design of FIR QMF (Quadrature Mirror Filters) filters of perfect reconstruction and odd number of coefficients (even order). By design, these filters will have linear phase and integer delay. These filter pairs have many applications in wavelet transforms and other multi-frequency decompositions. Perfect reconstruction filters have been studied from long time ago but we still found publications about them.Comment: 3 pages, 5 figure

Quality-Based Conditional Processing in Multi-Biometrics: Application to Sensor Interoperability

As biometric technology is increasingly deployed, it will be common to replace parts of operational systems with newer designs. The cost and inconvenience of reacquiring enrolled users when a new vendor solution is incorporated makes this approach difficult and many applications will require to deal with information from different sources regularly. These interoperability problems can dramatically affect the performance of biometric systems and thus, they need to be overcome. Here, we describe and evaluate the ATVS-UAM fusion approach submitted to the quality-based evaluation of the 2007 BioSecure Multimodal Evaluation Campaign, whose aim was to compare fusion algorithms when biometric signals were generated using several biometric devices in mismatched conditions. Quality measures from the raw biometric data are available to allow system adjustment to changing quality conditions due to device changes. This system adjustment is referred to as quality-based conditional processing. The proposed fusion approach is based on linear logistic regression, in which fused scores tend to be log-likelihood-ratios. This allows the easy and efficient combination of matching scores from different devices assuming low dependence among modalities. In our system, quality information is used to switch between different system modules depending on the data source (the sensor in our case) and to reject channels with low quality data during the fusion. We compare our fusion approach to a set of rule-based fusion schemes over normalized scores. Results show that the proposed approach outperforms all the rule-based fusion schemes. We also show that with the quality-based channel rejection scheme, an overall improvement of 25% in the equal error rate is obtained.Comment: Published at IEEE Transactions on Systems, Man, and Cybernetics - Part A: Systems and Human

Combine use of Selected Schizosaccharomyces pombe and Lachancea thermotolerans Yeast Strains as an Alternative to the Traditional Malolactic Fermentation in Red Wine Production

Most red wines commercialized in the market use the malolactic fermentationprocess in order to ensure stability from a microbiological point of view. In this secondfermentation, malic acid is converted into L-lactic acid under controlled setups. Howeverthis process is not free from possible collateral effects that on some occasions produceoff-flavors, wine quality loss and human health problems. In warm viticulture regions suchas the south of Spain, the risk of suffering a deviation during the malolactic fermentationprocess increases due to the high must pH. This contributes to produce wines with highvolatile acidity and biogenic amine values. This manuscript develops a new red winemakingmethodology that consists of combining the use of two non-Saccharomyces yeast strains asan alternative to the traditional malolactic fermentation. In this method, malic acid is totallyconsumed by Schizosaccharomyces pombe, thus achieving the microbiological stabilizationobjective, while Lachancea thermotolerans produces lactic acid in order not to reduce andeven increase the acidity of wines produced from low acidity musts. This technique reducesthe risks inherent to the malolactic fermentation process when performed in warm regions.The result is more fruity wines that contain less acetic acid and biogenic amines than thetraditional controls that have undergone the classical malolactic fermentation

Synthesis of superparamagnetic iron(III) oxide nanowires in double-walled carbon nanotubes

The synthesis and characterization of superparamagnetic iron(III) oxide nanowires confined within double-walled carbon nanotubes by capillary filling with a melted precursor (iron iodide) followed by thermal treatment is reported for the first time

Dual-band class J power amplifier at 2.45 and 5.8 GHz for UAVs communications

A hybrid dual-band power amplifier (PA) prototype working at two Industrial, Scientific and Medical (ISM) bands, 2.4-2.5 GHz and 5.725-5.875 GHz, was designed for Unmanned Aerial Vehicles (UAVs) communication applications in Spain. Initially, two single-band PA prototypes centered at each band were designed to evaluate the single-band achievable RF performance. In all the PAs, the Gallium Nitride (GaN) Qorvo HEMT TGF2977-SM was used, as well as microstrip transmission lines technology. To achieve wideband, good linearity and efficiency, the PAs were designed in class J. The measured results for the dual-band PA prototype at the 2dB compression point at the lower and higher bands, respectively, are 14.8 dB and 11.2 dB of Transducer Power Gain ( GT ), 35.7 dBm and 34.8 dBm of RF output power (Pout) and 59.2% and 43.5% of Drain Efficiency ( η ). At 3dB compression the respective lower and higher bands results are 37.9 dBm and 37 dBm of Pout and 73.9% and 55% of η

Implementación de un dispositivo de intervención para la enseñanza y el aprendizaje de las partes del computado

El objetivo de esta investigación es Implementar un dispositivo de intervención (videotutorial) para la enseñanza y aprendizaje de las partes del computador en estudiantes de 50 de la I E D NEM sede "las Malvinas". En las instituciones se está viendo una educación de bajo rendimiento como consecuencia de la falta de métodos y estrategias didácticas, por tal razón las nuevas tecnologías de la información y la comunicación muestran una gran ventaja en la enseñanza, puesto que son de gran ayuda para la educación a la hora de mejorar la calidad de los procesos de enseñanza y aprendizaje . Además de esto los métodos y estrategias de enseñanza hacen que el docente encuentre unas herramientas para implementar ayudas didácticas, de este modo, es el docente, el planificador, el diseñador de materiales o el programador de software educativo quien debe saber como,cuando, donde y por que utilizar recursos, métodos y estrategias de enseñanza. La utilización de las computadoras en la enseñanza es una necesidad debido al desarrollo que estas han tenido en los últimos años, por lo cual hoy hace falta integrar las NTIC como herramientas que ayuden en el proceso de aprendizaje en los alumnos, además estos medios constituyen una fuente de motivación para los estudiantes ya que son portadores de una novedad técnica para la mayoría de los escolares, posibilitando movilizar la atención del alumno durante el desarrollo de la actividad docente,aumentando su nivel de concentración, etc

Fingerprint Image-Quality Estimation and its Application to Multialgorithm Verification

Signal-quality awareness has been found to increase recognition rates and to support decisions in multisensor environments significantly. Nevertheless, automatic quality assessment is still an open issue. Here, we study the orientation tensor of fingerprint images to quantify signal impairments, such as noise, lack of structure, blur, with the help of symmetry descriptors. A strongly reduced reference is especially favorable in biometrics, but less information is not sufficient for the approach. This is also supported by numerous experiments involving a simpler quality estimator, a trained method (NFIQ), as well as the human perception of fingerprint quality on several public databases. Furthermore, quality measurements are extensively reused to adapt fusion parameters in a monomodal multialgorithm fingerprint recognition environment. In this study, several trained and nontrained score-level fusion schemes are investigated. A Bayes-based strategy for incorporating experts past performances and current quality conditions, a novel cascaded scheme for computational efficiency, besides simple fusion rules, is presented. The quantitative results favor quality awareness under all aspects, boosting recognition rates and fusing differently skilled experts efficiently as well as effectively (by training).Comment: Published at IEEE Transactions on Information Forensics and Securit

Cross-Sensor and Cross-Spectral Periocular Biometrics: A Comparative Benchmark including Smartphone Authentication

The massive availability of cameras results in a wide variability of imaging conditions, producing large intra-class variations and a significant performance drop if images from heterogeneous environments are compared for person recognition. However, as biometrics is deployed, it will be common to replace damaged or obsolete hardware, or to exchange information between applications in heterogeneous environments. Variations in spectral bands can also occur. For example, faces are typically acquired in the visible (VIS) spectrum, while iris is captured in near-infrared (NIR). However, cross-spectrum comparison may be needed if a face from a surveillance camera needs to be compared against a legacy iris database. Here, we propose a multialgorithmic approach to cope with periocular images from different sensors. We integrate different comparators with a fusion scheme based on linear logistic regression, in which scores tend to be log-likelihood ratios. This allows easy interpretation of output scores and the use of Bayes thresholds for optimal decision-making, since scores from different comparators are in the same probabilistic range. We evaluate our approach in the context of the Cross-Eyed Competition, whose aim was to compare recognition approaches when NIR and VIS periocular images are matched. Our approach achieves reductions in error rates of up to 30-40% in cross-spectral NIR-VIS comparisons, leading to EER=0.2% and FRR of just 0.47% at FAR=0.01%, representing the best overall approach of the competition. Experiments are also reported with a database of VIS images from different smartphones. We also discuss the impact of template size and computation times, with the most computationally heavy comparator playing an important role in the results. Lastly, the proposed method is shown to outperform other popular fusion approaches, such as the average of scores, SVMs or Random Forest

Study on the Connection Between the Set Transient in RRAMs and the Progressive Breakdown of Thin Oxides

In this paper, the transition rate (TR) from the high-resistance state to the low-resistance state of a HfO2-based resistive random access memory (RRAM) is investigated. The TR is statistically characterized by applying constant voltage stresses in the range from 0.45 to 0.65 V. It is found that TR follows a voltage dependence which closely resembles the one exhibited by metal-insulator-semiconductor / metal-insulator-metal structures when subjected to constant voltage stress, but with remarkably different fitting parameters. This result suggests a common underlying mechanism in both evolutionary behaviors. Furthermore, the investigation provides additional evidence supporting the micro-structural changes in the oxide after the forming step as well as the role played by the atomic species during the SET event.Fil: Aguirre, Fernando Leonel. Universidad Tecnológica Nacional. Facultad Regional Buenos Aires. Unidad de Investigación y Desarrollo de las Ingenierías; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rodriguez Fernandez, Alberto. Universitat Autònoma de Barcelona; EspañaFil: Pazos, Sebastián Matías. Universidad Tecnológica Nacional. Facultad Regional Buenos Aires. Unidad de Investigación y Desarrollo de las Ingenierías; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Suñé, Jordi. Universitat Autònoma de Barcelona; EspañaFil: Miranda, Enrique. Universitat Autònoma de Barcelona; EspañaFil: Palumbo, Felix Roberto Mario. Universidad Tecnológica Nacional. Facultad Regional Buenos Aires. Unidad de Investigación y Desarrollo de las Ingenierías; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin