Cryptographic key generation using handwritten signature

M. Freire-Santos ; J. Fierrez-Aguilar ; J. Ortega-Garcia; "Cryptographic key generation using handwritten signature", Biometric Technology for Human Identification III, Proc. SPIE 6202 (April 17, 2006); doi:10.1117/12.665875. Copyright 2006 Society of Photo‑Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.Proceedings of the III Biometric Technology for Human Identification (Orlando, Florida, USA)Based on recent works showing the feasibility of key generation using biometrics, we study the application of handwritten signature to cryptography. Our signature-based key generation scheme implements the cryptographic construction named fuzzy vault. The use of distinctive signature features suited for the fuzzy vault is discussed and evaluated. Experimental results are reported, including error rates to unlock the secret data by using both random and skilled forgeries from the MCYT database.This work has been supported by Spanish MCYT TIC2003-08382-C05-01 and by European Commission IST-2002-507634 Biosecure NoE projects

Feature selection based on genetic algorithms for on-line signature verification

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. J. Galbally, J. Fiérrez, M. R. Freire, J. Ortega-garcía, "Feature Selection Based on Genetic Algorithms for On-Line Signature Verification" in Workshop on Automatic Identification Advanced Technologies, 2007, 198 - 203.Two different genetic algorithm (GA) architectures are applied to a feature selection problem in on-line signature verification. The standard GA with binary coding is first used to find a suboptimal subset of features that minimizes the verification error rate of the system. The curse of dimensionality phenomenon is further investigated using a GA with integer coding. Results are given on the MCYT signature database comprising 330 users (16500 signatures). Signatures are represented by means of a set of 100 features which can be divided into four different groups according to the signature information they contain, namely: i) time, ii) speed and acceleration, iii) direction, and iv) geometry. The GA indicates that features from subsets i and iv are the most discriminative when dealing with random forgeries, while parameters from subsets ii and iv are the most appropriate to maximize the recognition rate with skilled forgeries.This work was supported by Spanish MEC under project TEC2006-13141-C03-03 and the European NoE Biosecure

Demonstration of negative refraction of microwaves

An experimental setup to demonstrate negative refraction is described. A simple method for designing and fabricating a metamaterial with negative refractive index at microwave frequencies is discussed. The metamaterial is made of a multilayer planar arrangement of flat unit cells. A prism was fabricated and used to demonstrate negative refraction at the prism-air interface. The prism is designed for demonstrations and works at the frequency of commercial microwave transmitters and receiver

Biometric system verification close to "real world" conditions

The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-642-04391-8_31Proceedings of Joint COST 2101 and 2102 International Conference, BioID_MultiComm 2009, Madrid, Spain.In this paper we present an autonomous biometric device developed in the framework of a national project. This system is able to capture speech, hand-geometry, online signature and face, and can open a door when the user is positively verified. Nevertheless the main purpose is to acquire a database without supervision (normal databases are collected in the presence of a supervisor that tells you what to do in front of the device, which is an unrealistic situation). This system will permit us to explain the main differences between what we call "real conditions" as opposed to "laboratory conditions".This work has been supported by FEDER and MEC, TEC2006-13141-C03/TCM, and COST-2102

Conductive polysaccharides-based proton-exchange membranes for fuel cell applications: the case of bacterial cellulose and fucoidan

Conductive natural-based separators for application in polymer electrolyte fuel cells (PEFCs) were fabricated by combining a bacterial polysaccharide, i.e. bacterial cellulose (BC), and an algae sulphated polysaccharide, i.e. fucoidan (Fuc). The diffusion of fucoidan aqueous solution containing a natural-based cross-linker, viz. tannic acid, into the wet BC nanofibrous three-dimensional network, followed by thermal cross-linking, originated fully bio-based proton exchange membranes (PEMs). The PEMs present thermal-oxidative stability in the range of 180-200 °C and good dynamic mechanical performance (storage modulus ≥ 460 MPa). Additionally, the BC/Fuc membranes exhibit protonic conductivity that increases with increasing relative humidity (RH), which is a typical feature for numerous water-mediated proton conductors. The traditional Arrhenius-type plots demonstrate a linear behaviour with a maximum protonic conductivity of 1.6 mS cm-1 at 94 °C and 98 % RH. The results showed that these fully bio-based conductive membranes have potential as eco-friendly alternatives to other PEMs for application in PEFCs.publishe

Using zeta-potential measurements to quantify peptide partition to lipid membranes

© The Author(s) 2011. This article is published with open access at Springerlink.com.Open Access: This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.Many cellular phenomena occur on the biomembranes. There are plenty of molecules (natural or xenobiotics) that interact directly or partially with the cell membrane. Biomolecules, such as several peptides (e.g., antimicrobial peptides) and proteins, exert their effects at the cell membrane level. This feature makes necessary investigating their interactions with lipids to clarify their mechanisms of action and side effects necessary. The determination of molecular lipid/water partition constants (Kp) is frequently used to quantify the extension of the interaction. The determination of this parameter has been achieved by using different methodologies, such as UV-Vis absorption spectrophotometry, fluorescence spectroscopy and ζ-potential measurements. In this work, we derived and tested a mathematical model to determine the Kp from ζ-potential data. The values obtained with this method were compared with those obtained by fluorescence spectroscopy, which is a regular technique used to quantify the interaction of intrinsically fluorescent peptides with selected biomembrane model systems. Two antimicrobial peptides (BP100 and pepR) were evaluated by this new method. The results obtained by this new methodology show that ζ-potential is a powerful technique to quantify peptide/lipid interactions of a wide variety of charged molecules, overcoming some of the limitations inherent to other techniques, such as the need for fluorescent labeling.This work was partially supported by project PTDC/QUI/ 69937/2006 from Fundação para a Ciência e Tecnologia-Ministério da Ciência, Tecnologia e Ensino Superior (FCT-MCTES, Portugal), and by Fundação Calouste Gulbenkian (Portugal). JMF and MMD also thank FCT-MCTES for grants IMM/BT/37-2010 and SFRH/BD/41750/2007, respectively

Educación y ambigüedades de la au tonomización: hacia una pedagogía crítica de la promoción del individuo autónomo

O presente artigo, confrontando a educação com o desiderato da autonomização, pretende analisar as ambiguidades a que esse confronto dá hoje origem e estabelecer, mediante a explicitação de uma conceção contra-hegemónica de autonomização, as bases e as coordenadas de uma pedagogia crítica da promoção do indivíduo autónomo, que seja simultaneamente humanista, emancipadora e transformadora tanto da realidade do sujeito quanto da realidade do contexto. A estrutura narrativa, em consonância com esse amplo propósito, articula as seguintes dimensões: a educação e a normatividade da autonomização; as ambiguidades da autonomização: sentidos divergentes de fazer educação para a autonomia; e, por fim, o empowerment emancipatório e transformador: vetor da educação enquanto autonomização contra-hegemónica. A conclusão aponta as linhas diretoras da construção de uma pedagogia crítica do indivíduo autónomo, assumida nas vertentes de emancipação individual e transformação social.This paper confronts education with the desideratum of autonomization and it intends to analyze the ambiguities that this confrontation leads and establishes, through the explanation of a counter-hegemonic conception of autonomization. The foundations and the coordinates of a critical pedagogy for the promotion of the autonomous individual that is humanistic, emancipator and transformative, both the reality of the subject and the reality of the context. The narrative structure, in line with that broad purpose, articulates the following dimensions: education and the normativeness of autonomization; the ambiguities of autonomization: divergent ways of making education for autonomy; the transformative and emancipatory empowerment; vector of education as counter-hegemonic autonomization. The conclusion points out the principal lines of the construction of a critical pedagogy of the autonomous individual taken in the areas of individual emancipation and social transformation.Este artículo, enfrentando la educación con el desideratumde la autonomización, pretende analizar las ambigüedades que surgen de dicha confrontación y establecer, mediante la explicitación de una concepción contrahegemónica de la autonomización, las bases y las líneas de una pedagogía crítica y al mismo tiempo humanista, emancipadora y transformadora (tanto de la realidad del sujeto como de la realidad del contexto) de la promoción del individuo autónomoLa estructura narrativa, en línea con dicho propósito, articula las siguientes dimensiones: la educación y la normatividad de la autonomización; las ambigüedades de la autonomización: diferentes sentidos de hacer educación para la autonomía y, por fin, el empoderamiento emancipador y transformador, vector de la educación como autonomización contrahegemónica. La conclusión señala las líneas maestras de la construcción de una pedagogía crítica del individuo autónomo en las vertientes de emancipación individual y transformación social.(undefined

Effectiveness and safety of guselkumab for the treatment of psoriasis in real-world settings at 24 weeks : A retrospective, observational, multicentre study by the Spanish Psoriasis Group

Altres ajuts: Acord transformatiu CRUE-CSICData on the effectiveness and safety of a drug in real-world clinical practice complement the evidence from clinical trials, which are carried out in a different setting. Little has been published on the effectiveness and safety of guselkumab in the treatment of psoriasis in clinical practice. The ojective of this study was to assess the effectiveness and safety of guselkumab at 24 weeks in patients with moderate to severe plaque psoriasis in routine clinical practice. A retrospective, multicentre study of adult patients with moderate to severe plaque psoriasis treated with guselkumab for at least 24 weeks was carried out in Spain. We studied 343 patients, 249 of whom were followed for 24 weeks. By week 24, the mean (SD) psoriasis area severity index (PASI) had decreased from 11.1 (7.3) to 1.7 (2.8) (−9.3; [−10.2;-8.4]), 85.9% of the patients had achieved PASI score of 4 or less and 77.9% a PASI score of 2 or less. In terms of relative PASI response, 59.4% of the patients achieved a PASI-90 response and 49.0% a PASI-100 response. On multivariate analysis, two factors reduced the probability of a PASI of 2 or less at 24 weeks: a BMI ≥30 (OR, 0.44; 95% CI, 0.22-0.88) and a greater previous exposure to biologic therapy (OR, 0.69; 95% CI, [0.56-0.84]). Adverse events were rare (9.9%) and led to withdrawal from treatment in only nine patients (2.6%) by the end of the follow-up period. The results of this study confirm the high efficacy and safety of guselkumab indicated by the clinical trial data. In clinical practice, the absolute PASI score appears to be a better marker of response to treatment than the relative value

Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

A measurement of the cosmic-ray spectrum for energies exceeding $4{\times}10^{18}$ eV is presented, which is based on the analysis of showers with zenith angles greater than $60^{\circ}$ detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above $5.3{\times}10^{18}$ eV, the "ankle", the flux can be described by a power law $E^{-\gamma}$ with index $\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)}$ followed by a smooth suppression region. For the energy ($E_\text{s}$) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find $E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19}$ eV.Comment: Replaced with published version. Added journal reference and DO