Likelihood ratio calibration in a transparent and testable forensic speaker recognition framework

Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. D. Ramos, J. González-Rodríguez, J. Ortega-garcía, "Likelihood Ratio Calibration in a Transparent and Testable Forensic Speaker Recognition Framework " in The Speaker and Language Recognition Workshop, ODYSSEY, San Juan (Puerto Rico), 2006, 1 - 8A recently reopened debate about the infallibility of some classical forensic disciplines is leading to new requirements in forensic science. Standardization of procedures, proficiency testing, transparency in the scientific evaluation of the evidence and testability of the system and protocols are emphasized in order to guarantee the scientific objectivity of the procedures. Those ideas will be exploited in this paper in order to walk towards an appropriate framework for the use of forensic speaker recognition in courts. Evidence is interpreted using the Bayesian approach for the analysis of the evidence, as a scientific and logical methodology, in a two-stage approach based in the similarity-typicality pair, which facilitates the transparency in the process. The concept of calibration as a way of reporting reliable and accurate opinions is also deeply addressed, presenting experimental results which illustrate its effects. The testability of the system is then accomplished by the use of the NIST SRE 2005 evaluation protocol. Recently proposed application-independent evaluation techniques (Cllr and APE curves) are finally addressed as a proper way for presenting results of proficiency testing in courts, as these evaluation metrics clearly show the influence of calibration errors in the accuracy of the inferential decision processThis work has been supported by the Spanish Ministry for Science and Technology under project TIC2003-09068-C02-01

El origen del azufre en mineralizaciones filonianas en el centro de la Península Ibérica

Sufphur isotope data from severa/ base metals-Ba-(F)-(Ag) and Ag-base metals vein-type deposits in the Central Jberian Zone of the Hesperian Massif suggest a magmatic and/or metasedimentary origin of this ore-forming component. Deposits exclusive/y hosted in metasediments (p.e. Alcudia Va/ley, type IV) display a magmatic signature. Even those /odes and stratabound deposits hosted by Permian-Triassic terrigenous and andesites (Las Torrecillas-Linares y Atienza) are formed by "igneous" sulphur

Bayesian analysis of fingerprint, face and signature evidences with automatic biometric systems

This is the author’s version of a work that was accepted for publication in Forensic Science International. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Forensic Science International, Vol 155, Issue 2 (20 December 2005) DOI: 10.1016/j.forsciint.2004.11.007The Bayesian approach provides a unified and logical framework for the analysis of evidence and to provide results in the form of likelihood ratios (LR) from the forensic laboratory to court. In this contribution we want to clarify how the biometric scientist or laboratory can adapt their conventional biometric systems or technologies to work according to this Bayesian approach. Forensic systems providing their results in the form of LR will be assessed through Tippett plots, which give a clear representation of the LR-based performance both for targets (the suspect is the author/source of the test pattern) and non-targets. However, the computation procedures of the LR values, especially with biometric evidences, are still an open issue. Reliable estimation techniques showing good generalization properties for the estimation of the between- and within-source variabilities of the test pattern are required, as variance restriction techniques in the within-source density estimation to stand for the variability of the source with the course of time. Fingerprint, face and on-line signature recognition systems will be adapted to work according to this Bayesian approach showing both the likelihood ratios range in each application and the adequacy of these biometric techniques to the daily forensic work.This work has been partially supported under MCYT Projects TIC2000-1683, TIC2000-1669, TIC2003-09068, TIC2003-08382 and Spanish Police Force ‘‘Guardia Civil’’ Research Program

HMM-based on-line signature verification: Feature extraction and signature modeling

This is the author’s version of a work that was accepted for publication in Pattern Recognition Letters. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Pattern Recognition Letters 28.16 (2007): 2325 – 2334, DOI: 10.1016/j.patrec.2007.07.012A function-based approach to on-line signature verification is presented. The system uses a set of time sequences and Hidden Markov Models (HMMs). Development and evaluation experiments are reported on a subcorpus of the MCYT bimodal biometric database comprising more than 7,000 signatures from 145 subjects. The system is compared to other state-of-the-art systems based on the results of the First International Signature Verification Competition (SVC 2004). A number of practical findings related to feature extraction and modeling are obtained.This work has been supported by the Spanish projects TIC2003-08382-C05- 01 and TEC2006-13141-C03-03, and by the European NoE Biosecure

La actividad metalogénica durante el Tardihercínico en el centro de España: una visión desde cinco localidades tipo

The most outstanding metallogenic period in central Spain took place during the so-cal/ed lateHercynian episode. This episode was characterized by widespread extensional conditions resulting from the collapse of an overthickened and overheated Hercynian orogen. A combination of magmatic activity and favorable structures induced hydrothermal activity leading to Sn-W, Pb-Zn, Ag-base metals, base metals-Ba-(F) and Sb-(Au) deposition. Five ore deposits/districts: El Trasquilón (Sn), Linares-La CarolinaTorrecillas (Pb-Zn-Ba-[Ag]), Sierra de Guadarrama (Ba-(F)-[base metals]), El Juncalón (Sb-[Au]), and Hiendelaencina (Ag-base metals) allow characterization of the main geologic features of this metallogenic episode.Depto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasTRUEpu

Safety analysis of modern heritage masonry buildings : box-buildings in Recife, Brazil

Box-buildings are structural masonry buildings named as such because of their shape. There are around 5,000 of them in Recife, Brazil. This paper presents a safety analysis of one box-building that suffered collapse on December 2007. The research aims at quantifying the safety of this type of existing buildings and at better understanding their structural behavior to try to identify the reasons for the collapse. A finite element model was prepared and a set of nonlinear numerical analyses were performed. The results of the analyses show good agreement between the observed damage in the real building and the damage achieved numerically at the current condition (LF=1). The model thus seems to represent satisfactorily the real behavior of the building but the safety factor obtained seems too conservative and does not justify the collapse observed in reality. Since results show that the building should not have failed under normal working conditions, a collapse assessment about why the building fell is therefore provided and a sensitivity analysis was performed in order to understand the importance of the material parameters and their influence on the structural response of the building

Amplificador de Potencia Clase-S para Transmisor EER

A Class-S power amplifier for an EER transmitter is shown in this paper. Simulations and measurements on a circuit prototype are presented showing good agreement. The amplifier is based on MOSFET technology both for the power stage and driver. Pulse Width Modulation driving signal required by the amplifier is generated by means of a in-house designed DSP board. Up to 50W output peak power can be delivered to the RF power amplifier (Class-S amplifier load) at 86 % power-added efficiency while harmonic distortion is below 30 dBc and third order intermodulaction products remain well below 34 dBc

Social Instruments and the Preservation of Species

[Resumo] A integración dos instrumentos sociais na xestión ambiental é un capítulo aínda pendiente. Neste artigo descríbense algúns dos problemas e as posibles solucións nun camiño de aprendizaxe mutuo entre educación e xestión[Abstract] The integration of social instruments in environmental management is still a pending issue. This article aims to describe some of the problems and possible solutions in a path of mutual learning between education and management

Nueva técnica de modulación de excitación para sistemas EER

This paper shows a novel drive modulation technique applied to a high power, high efficiency, linear Envelope Elimination and Restoration (EER) amplifier for L-Band. It comprises a mixed-mode suboptimum Class-E / Class-A wideband RF amplifier based on a dual GaN HEMT for RF carrier amplification and a high efficiency, high switching frequency, multi-phase, buck power converter based on Silicon LDMOS transistors to work as a modulator (or envelope amplifier). The linearity and power gain for this EER amplifier is improved by means of a new digital drive modulation technique and digital predistortion (DPD) to achieve linearity performances equivalent or better than Class-AB amplifiers of similar output power level and frequency band but exhibiting much higher efficiency. This EER amplifier provides 120W peak output power at the L-band without any adjustment. In a two tone test, measured third and fifth-order intermodulation products were -45 dBc and -49 dBc, respectively, reaching 67.5 % maximum PAE

Influence of stress control in the sports performance: self-confidence, anxiety and concentration in athletes

En esta investigación se realiza un estudio sobre el control del estrés en deportistas, utilizando como muestra 100 jugadores de fútbol semiprofesionales. Se parte de la consideración de que controlar el estrés para no llegar a estados de ansiedad es imprescindible, ya que alcanzar estos estados provoca efectos negativos en otras variables psicológicas del deportista, disminuyendo su autoconfianza y perjudicando el control atencional. El objetivo de esta investigación es describir los niveles de ansiedad, autoconfianza y atención-concentración en futbolistas semiprofesionales, mediante el análisis de la variable psicológica control del estrés. El instrumento utilizado para el estudio es la escala control del estrés del cuestionario de Características Psicológicas relacionadas con el Rendimiento Deportivo (CPRD). Como conclusiones del estudio, cabe destacar que desarrollar la habilidad psicológica de control del estrés, previene alcanzar estados de ansiedad y como consecuencia, posibilita mantener elevada la autoconfianza y una buena capacidad de atención-concentración durante la competición.In this research, a study on stress management in athletes is carried out with a sample of 100 semi-professional football players. Stress control is essential for avoiding a state of anxiety, as this state may have negative effects on other psychological variables of athletes, decreasing their self-confidence and harming their attentional control. The objective of this research is to describe anxiety, self-confidence, and attention-concentration levels in semi-professional footballers by means of analysing stress control. The instrument used for the study is the stress control scale from the Psychological Characteristics related to Sports Performance (CPRD) questionnaire. As a conclusion, it is noteworthy that developing the psychological ability of controlling stress prevents the appearance of anxiety states, allowing athletes to maintain high self-confidence and good attentionconcentration capacity during competitions