Image encryption system based on a nonlinear joint transform correlator for the simultaneous authentication of two users

We propose a new encryption system based on a nonlinear joint transform correlator (JTC) using the information of two biometrics (one digital fingerprint for each user) as security keys of the encryption system. In order to perform the decryption and authentication in a proper way, it is necessary to have the two digital fingerprints from the respective users whose simultaneous authentication is pursued. The proposed security system is developed in the Fourier domain. The nonlinearity of the JTC along with the five security keys given by the three random phase masks and the two digital fingerprints of the two users allow an increase of the system security against brute force and plaintext attacks. The feasibility and validity of this proposal is demonstrated using digital fingerprints as biometrics in numerical experiments.Peer ReviewedPostprint (published version

Effects of using an encrypted image corrupted by noise and occlusion in a security system based on joint transform correlator and Gyrator transform

Postprint (published version

Image quality and security through nonlinear joint transform encryption

Postprint (published version

The Ammonia Looping System for Mid-Temperature Thermochemical Energy Storage

Thermochemical reactions have a great potential for energy storage and transport. Their application to solar energy is of utmost interest because the possibility of reaching high energy densities and seasonal storage capacity. In this work, thermochemical energy storage of Concentrated Solar Power (CSP) based on an ammonia looping (AL) system is analysed. The AL process for energy storage is based on the reversible reaction of ammonia to produce hydrogen and nitrogen. Concentrating solar energy is used to carry out the decomposition endothermic reaction at temperatures around 650 ºC, which fits in the range of currently commercial CSP plants with tower technology. The stored energy is released through the reverse exothermic reaction. Our work is focused on energy integration in the system modelled by pinch analysis to optimize the process performance and competitiveness. As result a novel configuration is derived which is able to recover high-temperature heat for electricity production with a thermal-to-electric efficiency up to 27 %. The current study shows a clear interest of the system from an energy integration perspective. Further research should be conducted to access the potential for commercial applications

The Calcium-Looping (CaCO3/CaO) Process for Thermochemical Energy Storage in Concentrating Solar Power Plants

Articulo aceptado por la revista. * No publicado aún [28-06-2019]Energy storage based on thermochemical systems is gaining momentum as potential alternative to molten salts in Concentrating Solar Power (CSP) plants. This work is a detailed review about the promising integration of a CaCO3/CaO based system, the so-called Calcium-Looping (CaL) process, in CSP plants with tower technology. The CaL process relies on low cost, widely available and non-toxic natural materials (such as limestone or dolomite), which are necessary conditions for the commercial expansion of any energy storage technology at large scale. A comprehensive analysis of the advantages and challenges to be faced for the process to reach a commercial scale is carried out. The review includes a deep overview of reaction mechanisms and process integration schemes proposed in the recent literature. Enhancing the multicycle CaO conversion is a major challenge of the CaL process. Many lab-scale analyses carried out show that residual effective CaO conversion is highly dependent on the process conditions and CaO precursors used, reaching values as different as 0.07-0.82. The selection of the optimal operating conditions must be based on materials, process integration, technology and economics aspects. Global plant efficiencies over 45% (without considering solar-side losses) show the interest of the technology. Furthermore, the technological maturity and potential of the process is assessed. The direction towards which future works should be headed is discussed.Ministerio de Economia y Competitividad CTQ2014-52763-C2, CTQ2017- 83602-C2 (-1-R and -2-R)Unión Europea Horizon 2020 Grant agreement No 727348, project SOCRATCES

The mOxy-CaL Process: Integration of Membrane Separation, Partial Oxy-combustion and Calcium Looping for CO2 Capture

CO2 capture and storage (CCS) is considered as a key strategy in the short to medium term to mitigate global warming. The Calcium-Looping process, based on the reversible carbonation/calcination of CaO particles, is a promising technology for post-combustion CO2 capture because of the low cost and non-toxicity of natural CaO precursors and the minor energy penalty on the power plant in comparison with amines capture based technologies (4-9 % compared to 8-12 %). Another interesting process to reduce CO2 emissions in power plants is oxy-combustion, which is based on replacing the air used for combustion by a highly concentrated (~95 % v/v) O2 stream. This work proposes a novel process (mOxy-CaL) for post-combustion CO2 capture based on the integration of membrane separation, partial oxy-combustion and the Calcium-Looping process. An oxygenenriched air stream, which is obtained from air separation by using highly permeable polymeric membranes, is used to carry out partial oxy-combustion. The flue gas exiting partial oxy-combustion shows a CO2 concentration of ~30 % v/v (higher than 15 % v/v typical in coal power plants). After that, the flue gas is passed to the CaL process where the CO2 reacts with CaO solids according to the carbonation reaction. Thermogravimetric analysis show that the multicycle CaO conversion is enhanced as the CO2 concentration in the flue gas stream is increased. Process simulations show that the mOxy-CaL process has a high CO2 capture efficiency (~95%) with lower energy consumption per kg of CO2 avoided than previously proposed post-combustion CO2 capture technologies. Moreover, the overall system size is significantly lower that state-of-the-art CaL systems, which allows for an important reduction in the capital cost of the technology

Moralismo y esteticismo: Acerca de Patologías del juicio. Un ensayo sobre literatura, moral y estética nómada, de Carlos Pereda

Aestheticism and moralism are two vices in which aesthetic or moral values are overrated in situations where other values are at stake and should also be taken into account, but are underrated. Carlos Pereda maintains that they are pathologies of judgment and argues that literature has been the victim of different variants of these vices. To do this, he distinguishes between different forms of aestheticism and moralism, and analyzes how some of them have implications at the semantic and communication levels. Pereda proposes a “reflective model” that counteracts the simplification that these pathologies represent. In this note, I critically examine Pereda’s theory and propose other ways that the analysis of aestheticism and moralism can take.El esteticismo y el moralismo son dos vicios de desmesura en los que se sobredimensionan los valores estéticos o morales en situaciones en las que están en juego otros valores que también deberían tomarse en cuenta, pero se subvaloran. Carlos Pereda sostiene que son patologías del juicio y argumenta que la literatura ha sido víctima de distintas variantes de estos vicios. Para ello, distingue entre diferentes formas de esteticismo y de moralismo, y analiza cómo algunas de ellas tienen implicaciones a nivel semántico y de comunicación. Pereda propone un “modelo reflexivo” que contrarrestre el vértigo simplificador que representan estas patologías. En esta nota, examino críticamente la teoría de Pereda y propongo otros modos que puede tomar el análisis del esteticismo y del moralismo

Nussbaum on the cognitive nature of emotions

Abstract: Martha Nussbaum tells us that emotions are cognitive value judgments. She claims that her theory, the neo-Stoic theory of emotions, can handle traditional objections to cognitive theories of emotions. However, in this paper I hold that she improperly takes advantage of the ambiguity of the term "cognition": she faces the problems that arise when the term "cognition" is used in a very narrow sense (which claims that emotions are beliefs), resorting to a very wide sense under which any mental process is cognitive. I argue that this move does not solve the problems of the traditional cognitive theories of emotions. In order to show this, I distinguish four senses in which the term "cognitive" is used in theories of emotions, I analyze the ways Nussbaum uses them and why this move does not solve the traditional objections

Las variedades de fundacionismo y antifundacionismo ético: un mapa

In his book Vértigos argumentales, Carlos Pereda proposes a classification of foundationalist and anti-foundationalist theories of epistemic justification and suggests that something similar can be done about practical justification. Here I develop a classification of theories of moral justification in the same terms. Finally, I analyze how what Pereda calls a multi-foundationalist theory of moral justification would be like.En Vértigos argumentales, Carlos Pereda propone una clasificación de teorías fundacionistas sobre la justificación epistémica y sugiere que algo similar se puede hacer para la justificación práctica. Aquí desarrollo una clasificación de teorías acerca de la justificación moral en los mismos términos. Finalmente, analizo cómo sería lo que Pereda llama una teoría multifundacionista de la justificación en ética

Value Judgments, Truth and Objectivity

En este ensayo discuto si deberíamos entender la objetividad que predicamos de juicios evaluativos en los mismos términos en que lo hacemos de juicios epistémicos. Argumento a favor de un entendimiento de dominio específico de la objetividad, según el cual deberíamos ver a la verdad como central para la objetividad epistémica, pero no para la objetividad evaluativa. Sin embargo, esta posición tradicionalmente ha conducido a ver los juicios evaluativos como subjetivos. Aquí argumento que la carencia de valores de verdad no necesariamente conduce al subjetivismo; no, si no se conciben los juicios evaluativos como expresiones de sentimientos o deseos sin ninguna restricción racional. Más que en el concepto de verdad, en el caso de la objetividad de juicios evaluativos, el énfasis debe ponerse en el de justificación. Sin embargo, este concepto por sí solo no es garante de objetividad (del mismo modo en que tampoco lo es el de verdad). Trato de ahondar en algunas de las condiciones para predicar objetividad de juicios evaluativos y para ello también distingo entre tipos de objetividad. Abstract In this essay I discuss whether we should understand the objectivity of evaluative judgments in the same terms as we do with epistemic judgments. I argue for a domain-specific understanding of objectivity, according to which we should see truth as central to epistemic objectivity, but not to evaluative objectivity. However, this position has traditionally led to see these judgments as subjective. Here I argue that the lack of truth values does not necessarily lead to subjectivism—not if we do not conceive evaluative judgments as expressions of feelings or desires without any rational constraints. In the case of the objectivity of evaluative judgments, the emphasis should go on justification, rather than on truth. However, justification alone is no guarantee of objectivity (but, in the same way, neither is truth). I try to delve into some of the conditions necessary to claim objectivity of evaluative judgments and also distinguish between types of objectivity