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    Biometric presentation attack detection: beyond the visible spectrum

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    The increased need for unattended authentication in multiple scenarios has motivated a wide deployment of biometric systems in the last few years. This has in turn led to the disclosure of security concerns specifically related to biometric systems. Among them, presentation attacks (PAs, i.e., attempts to log into the system with a fake biometric characteristic or presentation attack instrument) pose a severe threat to the security of the system: any person could eventually fabricate or order a gummy finger or face mask to impersonate someone else. In this context, we present a novel fingerprint presentation attack detection (PAD) scheme based on i) a new capture device able to acquire images within the short wave infrared (SWIR) spectrum, and i i) an in-depth analysis of several state-of-theart techniques based on both handcrafted and deep learning features. The approach is evaluated on a database comprising over 4700 samples, stemming from 562 different subjects and 35 different presentation attack instrument (PAI) species. The results show the soundness of the proposed approach with a detection equal error rate (D-EER) as low as 1.35% even in a realistic scenario where five different PAI species are considered only for testing purposes (i.e., unknown attacks

    Analyzing eyebrow region for morphed image detection

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    Facial images in passports are designated as primary identifiers for the verification of travelers according to the International Civil Aviation Organization (ICAO). Hence, it is important to ascertain the sanctity of the facial images stored in the electronic Machine-Readable Travel Document (eMRTD). With the introduction of automated border control (ABC) systems that rely on face recognition for the verification of travelers, it is even more crucial to have a system to ensure that the image stored in the eMRTD is free from any alteration that can hinder or abuse the normal working of a facial recognition system. One such attack against these systems is the face-morphing attack. Even though many techniques exist to detect morphed images, morphing algorithms are also improving to evade these detections. In this work, we analyze the eyebrow region for morphed image detection. The proposed method is based on analyzing the frequency content of the eyebrow region. The method was evaluated on two datasets that each consisted of morphed images created using two algorithms. The findings suggest that the proposed method can serve as a valuable tool in morphed image detection, and can be used in various applications where image authenticity is critical

    Homomorphic Encryption for Speaker Recognition: Protection of Biometric Templates and Vendor Model Parameters

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    Data privacy is crucial when dealing with biometric data. Accounting for the latest European data privacy regulation and payment service directive, biometric template protection is essential for any commercial application. Ensuring unlinkability across biometric service operators, irreversibility of leaked encrypted templates, and renewability of e.g., voice models following the i-vector paradigm, biometric voice-based systems are prepared for the latest EU data privacy legislation. Employing Paillier cryptosystems, Euclidean and cosine comparators are known to ensure data privacy demands, without loss of discrimination nor calibration performance. Bridging gaps from template protection to speaker recognition, two architectures are proposed for the two-covariance comparator, serving as a generative model in this study. The first architecture preserves privacy of biometric data capture subjects. In the second architecture, model parameters of the comparator are encrypted as well, such that biometric service providers can supply the same comparison modules employing different key pairs to multiple biometric service operators. An experimental proof-of-concept and complexity analysis is carried out on the data from the 2013-2014 NIST i-vector machine learning challenge

    ¿Se pueden alcanzar los objetivos de la escuela de Frankfurt mediante la teoría del reconocimiento? Reflexiones a propósito de la controversia en el campo de la filosofía política de Nancy Fraser y Axel Honneth

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    De los estudios en ciencias sociales de mayor impacto se deduce que la política de mercantilización y desestructuración de las instituciones del Estado social practicada en los últimos treinta años, pri mero en Gran Bretaña, los Estados Unidos y Nueva Zelanda y después en el continente europeo, generará formas de empleo que, cada vez más, serían experimentadas por las personas como pro blemáticas o amenazantes (cf ., p. ej ., Bourdieu et al., 1997, Castel, 2000 y 2005, así como Sennet 1998 y 2005). Parecen responsables de este hecho, ante todo, las exigencias de movilidad que aumentan con la flexibilización de las estructuras de empleo, así como también un fuerte incremento de las ocupaciones inestables y mal pagadas (como, por ejemplo, los trabajos tempora les o a tiempo parcial). Según la apreciación de destacados sociólogos, aquellas estructuras de ocupación resultan problemáticas para muchas personas no únicamente en sentido material, sino también en sentido normativo: no sólo acarrean una situación de conflict o en el mantenimiento de la propia vida, sino que también dificultan la formación del autoaprecio y de la autoestima de una parte de la ciudadanía. A la vista de esta circunstancias , no resulta sorprendente que las cuesti ones del mundo del trabajo hayan sido discutidas ampliamente por personas que se dedican tanto a las ciencias sociales y a la ética de la economía, como también a la filosofía política o social. Para la Teoría Crítica en la tradición de la Escuela de Frankfurt , la discusión sobre los modernos mundos del trabajo resulta tradicionalmente un tema central. La peculiaridad de su planteamiento (interdis ciplinar) consiste , según la convicción de dos de sus más prominentes representantes, en : fusionar aquellos planos que provienen de la filosofía moral, de la teoría de la sociedad y del análisis político, en una teoría crítica del capitalismo (Fraser & Honnet h, 2003: 10). Lo que se plantea en esta perspectiva es un análisis y una crítica

    Compaction and cementation control on bleaching in Triassic fluvial red beds, S-Germany

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    This study focusses on bleaching phenomena on the pore scale in an Olenekian (Upper Buntsandstein) sandstone quarry. The study area exposes a 10 m thick red sandstone body with up to cm-sized, greyish-white laminae in sandstones. Analyses focus on bleached and unbleached zones in the same cm-sized samples. Bleached zones show a larger grain size (by 27 μm), less compaction and a higher porosity (by 3 %). They also exhibit stronger cementation by all observed authigenic phases of quartz, illite, K-feldspar and to a minor extent dolomite. Calculated intergranular volumes and cementational porosity loss also correlate positively with bleaching. Meanwhile unbleached zones contain more ductile grains (e.g. micas, detrital clay, rock fragments like phyllites and plutonic rock fragments) and are affected by major porosity loss via compaction. Bleaching is related to primary features like grain size-selective lamination and associated higher permeability in coarse-grained laminae. It is also reliant onto an early framework stabilising cement phase, which keeps pathways open for uplift-related leaching of the detritus and few dolomite cements
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