Integrated luminescent chemical microsensors based on GaN LEDs for security applications using smartphones

Development of PCB-integrateable microsensors for monitoring chemical species is a goal in areas such as lab-on-a-chip analytical devices, diagnostics medicine and electronics for hand-held instruments where the device size is a major issue. Cellular phones have pervaded the world inhabitants and their usefulness has dramatically increased with the introduction of smartphones due to a combination of amazing processing power in a confined space, geolocalization and manifold telecommunication features. Therefore, a number of physical and chemical sensors that add value to the terminal for health monitoring, personal safety (at home, at work) and, eventually, national security have started to be developed, capitalizing also on the huge number of circulating cell phones. The chemical sensor-enabled ���super��� smartphone provides a unique (bio)sensing platform for monitoring airborne or waterborne hazardous chemicals or microorganisms for both single user and crowdsourcing security applications. Some of the latest ones are illustrated by a few examples. Moreover, we have recently achieved for the first time (covalent) functionalization of p- and n-GaN semiconductor surfaces with tuneable luminescent indicator dyes of the Ru-polypyridyl family, as a key step in the development of innovative microsensors for smartphone applications. Chemical ���sensoring��� of GaN-based blue LED chips with those indicators has also been achieved by plasma treatment of their surface, and the micrometer-sized devices have been tested to monitor O2 in the gas phase to show their full functionality. Novel strategies to enhance the sensor sensitivity such as changing the length and nature of the siloxane buffer layer are discussed in this paper.

Security of plug-and-play QKD arrangements with finite resources

The security of a passive plug-and-play QKD arrangement in the case of finite (resources) key lengths is analysed. It is assumed that the eavesdropper has full access to the channel so an unknown and untrusted source is assumed. To take into account the security of the BB84 protocol under collective attacks within the framework of quantum adversaries, a full treatment provides the well-known equations for the secure key rate. A numerical simulation keeping a minimum number of initial parameters constant as the total error sought and the number of pulses is carried out. The remaining parameters are optimized to produce the maximum secure key rate. Two main strategies are addressed: with and without two-decoy-states including the optimization of signal to decoy relationship.

New methodology for the integration of biometric features in speaker recognition systems applied to security environments

La cuesti��n principal abordada en esta tesis doctoral es la mejora de los sistemas biom��tricos de reconocimiento de personas a partir de la voz, proponiendo el uso de una nueva parametrizaci��n, que hemos denominado parametrizaci��n biom��trica extendida dependiente de g��nero (GDEBP en sus siglas en ingl��s). No se propone una ruptura completa respecto a los par��metros cl��sicos sino una nueva forma de utilizarlos y complementarlos. En concreto, proponemos el uso de par��metros diferentes dependiendo del g��nero del locutor, ya que como es bien sabido, la voz masculina y femenina presentan caracter��sticas diferentes que deber��n modelarse, por tanto, de diferente manera. Adem��s complementamos los par��metros cl��sicos utilizados (MFFC extra��dos de la se��al de voz), con un nuevo conjunto de par��metros extra��dos a partir de la deconstrucci��n de la se��al de voz en sus componentes de fuente gl��tica (m��s relacionada con el proceso y ��rganos de fonaci��n y por tanto con caracter��sticas f��sicas del locutor) y de tracto vocal (m��s relacionada con la articulaci��n ac��stica y por tanto con el mensaje emitido). Para verificar la validez de esta propuesta se plantean diversos escenarios, utilizando diferentes bases de datos, para validar que la GDEBP permite generar una descripci��n m��s precisa de los locutores que los par��metros MFCC cl��sicos independientes del g��nero. En concreto se plantean diferentes escenarios de identificaci��n sobre texto restringido y texto independiente utilizando las bases de datos de HESPERIA y ALBAYZIN. El trabajo tambi��n se completa con la participaci��n en dos competiciones internacionales de reconocimiento de locutor, NIST SRE (2010 y 2012) y MOBIO 2013. En el primer caso debido a la naturaleza de las bases de datos utilizadas se obtuvieron resultados cercanos al estado del arte, mientras que en el segundo de los casos el sistema presentado obtuvo la mejor tasa de reconocimiento para locutores femeninos. A pesar de que el objetivo principal de esta tesis no es el estudio de sistemas de clasificaci��n, s�� ha sido necesario analizar el rendimiento de diferentes sistemas de clasificaci��n, para ver el rendimiento de la parametrizaci��n propuesta. En concreto, se ha abordado el uso de sistemas de reconocimiento basados en el paradigma GMM-UBM, supervectores e i-vectors. Los resultados que se presentan confirman que la utilizaci��n de caracter��sticas que permitan describir los locutores de manera m��s precisa es en cierto modo m��s importante que la elecci��n del sistema de clasificaci��n utilizado por el sistema. En este sentido la parametrizaci��n propuesta supone un paso adelante en la mejora de los sistemas de reconocimiento biom��trico de personas por la voz, ya que incluso con sistemas de clasificaci��n relativamente simples se consiguen tasas de reconocimiento realmente competitivas. ABSTRACT The main question addressed in this thesis is the improvement of automatic speaker recognition systems, by the introduction of a new front-end module that we have called Gender Dependent Extended Biometric Parameterisation (GDEBP). This front-end do not constitute a complete break with respect to classical parameterisation techniques used in speaker recognition but a new way to obtain these parameters while introducing some complementary ones. Specifically, we propose a gender-dependent parameterisation, since as it is well known male and female voices have different characteristic, and therefore the use of different parameters to model these distinguishing characteristics should provide a better characterisation of speakers. Additionally, we propose the introduction of a new set of biometric parameters extracted from the components which result from the deconstruction of the voice into its glottal source estimate (close related to the phonation process and the involved organs, and therefore the physical characteristics of the speaker) and vocal tract estimate (close related to acoustic articulation and therefore to the spoken message). These biometric parameters constitute a complement to the classical MFCC extracted from the power spectral density of speech as a whole. In order to check the validity of this proposal we establish different practical scenarios, using different databases, so we can conclude that a GDEBP generates a more accurate description of speakers than classical approaches based on gender-independent MFCC. Specifically, we propose scenarios based on text-constrain and text-independent test using HESPERIA and ALBAYZIN databases. This work is also completed with the participation in two international speaker recognition evaluations: NIST SRE (2010 and 2012) and MOBIO 2013, with diverse results. In the first case, due to the nature of the NIST databases, we obtain results closed to state-of-the-art although confirming our hypothesis, whereas in the MOBIO SRE we obtain the best simple system performance for female speakers. Although the study of classification systems is beyond the scope of this thesis, we found it necessary to analise the performance of different classification systems, in order to verify the effect of them on the propose parameterisation. In particular, we have addressed the use of speaker recognition systems based on the GMM-UBM paradigm, supervectors and i-vectors. The presented results confirm that the selection of a set of parameters that allows for a more accurate description of the speakers is as important as the selection of the classification method used by the biometric system. In this sense, the proposed parameterisation constitutes a step forward in improving speaker recognition systems, since even when using relatively simple classification systems, really competitive recognition rates are achieved.

Analysis of the impact of globalization and economic growth on food security in developing countries

A pesar de los importantes avances en la reducci��n del hambre, la seguridad alimentaria contin��a siendo un reto de dimensi��n internacional. La seguridad alimentaria es un concepto amplio y multidimensional, cuyo an��lisis abarca distintas escalas y horizontes temporales. Dada su complejidad, la identificaci��n de las causas de la inseguridad alimentaria y la priorizaci��n de las medias para abordarlas, son dos cuestiones que suscitan un intenso debate en la actualidad. El objetivo de esta tesis es evaluar el impacto de la globalizaci��n y el crecimiento econ��mico en la seguridad alimentaria en los pa��ses en desarrollo, desde una perspectiva macro y un horizonte temporal a largo plazo. La influencia de la globalizaci��n se aborda de una manera secuencial. En primer lugar, se analiza la relaci��n entre la inversi��n p��blico-privada en infraestructuras y las exportaciones agrarias. A continuaci��n, se estudia el impacto de las exportaciones agrarias en los indicadores de seguridad alimentaria. El estudio del impacto del crecimiento econ��mico aborda los cambios paralelos en la distribuci��n de la renta, y c��mo la inequidad influye en el comportamiento de la seguridad alimentaria nacional. Adem��s, se analiza en qu�� medida el crecimiento econ��mico contribuye a acelerar el proceso de mejora de la seguridad alimentaria. Con el fin de conseguir los objetivos mencionados, se llevan a cabo varios an��lisis econom��tricos basados en datos de panel, en el que se combinan datos de corte transversal de 52 pa��ses y datos temporales comprendidos en el periodo 1991-2012. Se analizan tanto variables en niveles como variables en tasas de cambio anual. Se aplican los modelos de estimaci��n de efectos variables y efectos fijos, ambos en niveles y en primeras diferencias. La tesis incluye cuatro tipos de modelos econom��tricos, cada uno de ellos con sus correspondientes pruebas de robustez y especificaciones. Los resultados matizan la importancia de la globalizaci��n y el crecimiento econ��mico como mecanismos de mejora de la seguridad alimentaria en los pa��ses en desarrollo. Se obtienen dos conclusiones relativas a la globalizaci��n. En primer lugar, los resultados sugieren que la promoci��n de las inversiones privadas en infraestructuras contribuye a aumentar las exportaciones agrarias. En segundo lugar, se observa que las exportaciones agrarias pueden tener un impacto negativo en los indicadores de seguridad alimentaria. La combinaci��n de estas dos conclusiones sugiere que la apertura comercial y financiera no contribuye por s�� misma a la mejora de la seguridad alimentaria en los pa��ses en desarrollo. La apertura internacional de los pa��ses en desarrollo ha de ir acompa��ada de pol��ticas e inversiones que desarrollen sectores productivos de alto valor a��adido, que fortalezcan la econom��a nacional y reduzcan su dependencia exterior. En relaci��n al crecimiento econ��mico, a pesar del incuestionable hecho de que el crecimiento econ��mico es una condici��n necesaria para reducir los niveles de subnutrici��n, no es una condici��n suficiente. Se han identificado tres estrategias adicionales que han de acompa��ar al crecimiento econ��mico con el fin de intensificar su impacto positivo sobre la subnutrici��n. Primero, es necesario que el crecimiento econ��mico sea acompa��ado de una distribuci��n m��s equitativa de los ingresos. Segundo, el crecimiento econ��mico ha de reflejarse en un aumento de inversiones en salud, agua y saneamiento y educaci��n. Se observa que, incluso en ausencia de crecimiento econ��mico, mejoras en el acceso a agua potable contribuyen a reducir los niveles de poblaci��n subnutrida. Tercero, el crecimiento econ��mico sostenible en el largo plazo parece tener un mayor impacto positivo sobre la seguridad alimentaria que el crecimiento econ��mico m��s vol��til o inestable en el corto plazo. La estabilidad macroecon��mica se identifica como una condici��n necesaria para alcanzar una mayor mejora en la seguridad alimentaria, incluso habi��ndose mejorado la equidad en la distribuci��n de los ingresos. Por ��ltimo, la tesis encuentra que los pa��ses en desarrollo analizados han experimentado diferentes trayectorias no lineales en su proceso de mejora de sus niveles de subnutrici��n. Los resultados sugieren que un mayor nivel inicial de subnutrici��n y el crecimiento econ��mico son responsables de una respuesta m��s r��pida al reto de la mejora de la seguridad alimentaria. ABSTRACT Despite the significant reductions of hunger, food security still remains a global challenge. Food security is a wide concept that embraces multiple dimensions, and has spatial-temporal scales. Because of its complexity, the identification of the drivers underpinning food insecurity and the prioritization of measures to address them are a subject of intensive debate. This thesis attempts to assess the impact of globalization and economic growth on food security in developing countries with a macro level scale (country) and using a long-term approach. The influence of globalization is addressed in a sequential way. First, the impact of public-private investment in infrastructure on agricultural exports in developing countries is analyzed. Secondly, an assessment is conducted to determine the impact of agricultural exports on food security indicators. The impact of economic growth focuses on the parallel changes in income inequality and how the income distribution influences countries' food security performance. Furthermore, the thesis analyzes to what extent economic growth helps accelerating food security improvements. To address the above mentioned goals, various econometric models are formulated. Models use panel data procedures combining cross-sectional data of 52 countries and time series data from 1991 to 2012. Yearly data are expressed both in levels and in changes. The estimation models applied are random effects estimation and fixed effects estimations, both in levels and in first differences. The thesis includes four families of econometric models, each with its own set of robustness checks and specifications. The results qualify the relevance of globalization and economic growth as enabling mechanisms for improving food security in developing countries. Concerning globalization, two main conclusions can be drawn. First, results showed that enhancing foreign private investment in infrastructures contributes to increase agricultural exports. Second, agricultural exports appear to have a negative impact on national food security indicators. These two conclusions suggest that trade and financial openness per se do not contribute directly to improve food security in development countries. Both measures should be accompanied by investments and policies to support the development of national high value productive sectors, to strengthen the domestic economy and reduce its external dependency. Referring to economic growth, despite the unquestionable fact that income growth is a pre-requisite for reducing undernourishment, results suggest that it is a necessary but not a sufficient condition. Three additional strategies should accompany economic growth to intensifying its impact on food security. Firstly, it is necessary that income growth should be accompanied by a better distribution of income. Secondly, income growth needs to be followed by investments and policies in health, sanitation and education to improve food security. Even if economic growth falters, sustained improvements in the access to drinking water may still give rise to reductions in the percentage of undernourished people. And thirdly, long-term economic growth appears to have a greater impact on reducing hunger than growth regimes that combine periods of growth peaks followed by troughs. Macroeconomic stability is a necessary condition for accelerating food security. Finally, the thesis finds that the developing countries analyzed have experienced different non-linear paths toward improving food security. Results also show that a higher initial level of undernourishment and economic growth result in a faster response for improving food security.

Cognitive strategies for security in wireless sensor networks

Las redes de sensores inal��mbricas son uno de los sectores con m��s crecimiento dentro de las redes inal��mbricas. La r��pida adopci��n de estas redes como soluci��n para muchas nuevas aplicaciones ha llevado a un creciente tr��fico en el espectro radioel��ctrico. Debido a que las redes inal��mbricas de sensores operan en las bandas libres Industrial, Scientific and Medical (ISM) se ha producido una saturaci��n del espectro que en pocos a��os no permitir�� un buen funcionamiento. Con el objetivo de solucionar este tipo de problemas ha aparecido el paradigma de Radio Cognitiva (CR). La introducci��n de las capacidades cognitivas en las redes inal��mbricas de sensores permite utilizar estas redes para aplicaciones con unos requisitos m��s estrictos respecto a fiabilidad, cobertura o calidad de servicio. Estas redes que a��nan todas estas caracter��sticas son llamadas redes de sensores inal��mbricas cognitivas (CWSNs). La mejora en prestaciones de las CWSNs permite su utilizaci��n en aplicaciones cr��ticas donde antes no pod��an ser utilizadas como monitorizaci��n de estructuras, de servicios m��dicos, en entornos militares o de vigilancia. Sin embargo, estas aplicaciones tambi��n requieren de otras caracter��sticas que la radio cognitiva no nos ofrece directamente como, por ejemplo, la seguridad. La seguridad en CWSNs es un aspecto poco desarrollado al ser una caracter��stica no esencial para su funcionamiento, como pueden serlo el sensado del espectro o la colaboraci��n. Sin embargo, su estudio y mejora es esencial de cara al crecimiento de las CWSNs. Por tanto, esta tesis tiene como objetivo implementar contramedidas usando las nuevas capacidades cognitivas, especialmente en la capa f��sica, teniendo en cuenta las limitaciones con las que cuentan las WSNs. En el ciclo de trabajo de esta tesis se han desarrollado dos estrategias de seguridad contra ataques de especial importancia en redes cognitivas: el ataque de simulaci��n de usuario primario (PUE) y el ataque contra la privacidad eavesdropping. Para mitigar el ataque PUE se ha desarrollado una contramedida basada en la detecci��n de anomal��as. Se han implementado dos algoritmos diferentes para detectar este ataque: el algoritmo de Cumulative Sum y el algoritmo de Data Clustering. Una vez comprobado su validez se han comparado entre s�� y se han investigado los efectos que pueden afectar al funcionamiento de los mismos. Para combatir el ataque de eavesdropping se ha desarrollado una contramedida basada en la inyecci��n de ruido artificial de manera que el atacante no distinga las se��ales con informaci��n del ruido sin verse afectada la comunicaci��n que nos interesa. Tambi��n se ha estudiado el impacto que tiene esta contramedida en los recursos de la red. Como resultado paralelo se ha desarrollado un marco de pruebas para CWSNs que consta de un simulador y de una red de nodos cognitivos reales. Estas herramientas han sido esenciales para la implementaci��n y extracci��n de resultados de la tesis. ABSTRACT Wireless Sensor Networks (WSNs) are one of the fastest growing sectors in wireless networks. The fast introduction of these networks as a solution in many new applications has increased the traffic in the radio spectrum. Due to the operation of WSNs in the free industrial, scientific, and medical (ISM) bands, saturation has ocurred in these frequencies that will make the same operation methods impossible in the future. Cognitive radio (CR) has appeared as a solution for this problem. The networks that join all the mentioned features together are called cognitive wireless sensor networks (CWSNs). The adoption of cognitive features in WSNs allows the use of these networks in applications with higher reliability, coverage, or quality of service requirements. The improvement of the performance of CWSNs allows their use in critical applications where they could not be used before such as structural monitoring, medical care, military scenarios, or security monitoring systems. Nevertheless, these applications also need other features that cognitive radio does not add directly, such as security. The security in CWSNs has not yet been explored fully because it is not necessary field for the main performance of these networks. Instead, other fields like spectrum sensing or collaboration have been explored deeply. However, the study of security in CWSNs is essential for their growth. Therefore, the main objective of this thesis is to study the impact of some cognitive radio attacks in CWSNs and to implement countermeasures using new cognitive capabilities, especially in the physical layer and considering the limitations of WSNs. Inside the work cycle of this thesis, security strategies against two important kinds of attacks in cognitive networks have been developed. These attacks are the primary user emulator (PUE) attack and the eavesdropping attack. A countermeasure against the PUE attack based on anomaly detection has been developed. Two different algorithms have been implemented: the cumulative sum algorithm and the data clustering algorithm. After the verification of these solutions, they have been compared and the side effects that can disturb their performance have been analyzed. The developed approach against the eavesdropping attack is based on the generation of artificial noise to conceal information messages. The impact of this countermeasure on network resources has also been studied. As a parallel result, a new framework for CWSNs has been developed. This includes a simulator and a real network with cognitive nodes. This framework has been crucial for the implementation and extraction of the results presented in this thesis.

Evaluating sustainability and food security of peasant farming systems in Mesoamerican highlands

En las ��ltimas d��cadas, la agricultura sostenible ha sido objeto de gran inter��s y debate acad��mico, no s��lo en t��rminos conceptuales, sino tambi��n en t��rminos metodol��gicos. La persistencia de la inseguridad alimentaria y el deterioro de los recursos naturales en muchas regiones del mundo, ha provocado el surgimiento de numerosas iniciativas centradas en revitalizar la agricultura campesina as�� como renovadas discusiones sobre el rol que juega la agricultura como motor de desarrollo y principal actividad para alivio de la pobreza. Por ello, cuando hablamos de evaluar sistemas campesinos de monta��a, debemos considerar tanto la dimensi��n alimentaria como las especificidades propias de los sistemas monta��osos como base fundamental de la sostenibilidad. Al evaluar la contribuci��n que han hecho alternativas tecnol��gicas y de manejo en la mejora de la sostenibilidad y la seguridad alimentaria de los sistemas campesinos de monta��a en Mesoam��rica, surgen tres preguntas de investigaci��n: ��� ��Se est�� evaluando la sostenibilidad de los sistemas campesinos teniendo en cuenta la variabilidad clim��tica, la participaci��n de los agricultores y las din��micas temporales? ��� ��Podemos rescatar tendencias comunes en estos sistemas y extrapolar los resultados a otras zonas? ��� ��Son inequ��vocamente positivas las alternativas propuestas que se han llevado a cabo? En este trabajo se presentan tres evaluaciones de sostenibilidad que tratan de poner de manifiesto cu��les son los retos y oportunidades que enfrentan actualmente los sistemas campesinos de monta��a. En primer lugar, se eval��an tres sistemas de manejo agr��cola bajo dos a��os meteorol��gicamente contrastantes. Se determin�� que durante el a��o que experiment�� lluvias abundantes y temperaturas moderadas, los sistemas de bajos insumos, basados en el uso de abonos org��nicos y rotaci��n de cultivos, obtuvieron los mejores resultados en indicadores ecol��gicos y similares resultados en los econ��micos y sociales que el sistema de altos insumos qu��micos. En el segundo a��o, con heladas tempranas y sequ��a invernal, la productividad se redujo para todos los sistemas pero los sistemas m��s diversificados (en variedades de ma��z y/o siembra de otros cultivos) pudieron resistir mejor los contratiempos clim��ticos. En segundo lugar, se eval��a el grado de conocimiento (percepci��n) campesino para determinar los factores claves que determinan la sostenibilidad de sus sistemas y su seguridad alimentaria. Se determin�� que los principales puntos cr��ticos identificados por los campesinos (tama��o de parcela y pendiente del terreno) afectan de forma significativa a cuestiones de ��ndole econ��mica, pero no son capaces de explicar los desequilibrios alimenticios existentes. Realizando un an��lisis comparativo entre comunidades que presentaban buenos y malos resultados en cuanto a aporte energ��tico y proteico, se determin�� que la seguridad alimentaria estaba relacionada con la sostenibilidad de los sistemas y que concretamente estaba ligada a los atributos de equidad y autonom��a. Otro resultado destacable fue que las comunidades m��s marginales y con mayor dificultad de acceso mostraron mayores niveles de inseguridad alimentaria, pero la variabilidad intergrupal fue muy alta. Eso demuestra que la seguridad alimentaria y nutricional forma parte de un complejo sistema de estrategias de autoabastecimiento ligada a la idiosincrasia misma de cada uno de los hogares. En tercer lugar, se evalu�� el desempe��o de las escuelas de campo de agricultores (ECAs) en la mejora de la sostenibilidad y la seguridad alimentaria de un sistema campesino de monta��a. Para ver el efecto del impacto de estas metodolog��as a largo plazo, se estudiaron tres comunidades donde se hab��an implementado ECAs hace 8, 5 y 3 a��os. Encontramos que el impacto fue progresivo ya que fue la comunidad m��s antigua la que mejores valores obtuvo. El impacto de las ECAs fue r��pido y persistente en los indicadores relacionados con la participaci��n, el acceso a servicios b��sicos y la conservaci��n de los recursos naturales. El estudio demostr�� un claro potencial de las ECAs en la mejora general de la sostenibilidad y la seguridad alimentaria de estos sistemas, sin embargo se observ�� una relaci��n directa entre el aumento de producci��n agr��cola y el uso de insumos externos, lo que puede suponer un punto cr��tico para los ideales sostenibles. ABSTRACT During the last decades, sustainable agriculture has been the subject of considerable academic interest and debate, not only in conceptual terms, but also in methodological ones. The persistence of high levels of environmental degradation and food insecurity in many regions has led to new initiatives focused on revitalizing peasant agriculture and renewed discussions of the role of sustainable agriculture as an engine for development, environmental conservation and poverty alleviation. Therefore, to assess mountain farming systems, we must consider food dimension and taking into account the specificities of the mountain systems as the foundation of sustainability. When evaluating contribution of technological and management alternative proposals in achieving sustainability and food security for peasant farming systems in Mesoamerican highlands, three research questions arise: ��� Is sustainability of peasant-farming systems being evaluated taking into account climate variability, participation of farmers and temporal dynamics? ��� Can we rescue common trends in these systems and extrapolate the results to other areas? ��� What alternative proposals that have been conducted are unequivocally positives? In this document, we present three evaluations of sustainability that try to highlight the challenges and opportunities that currently face mountain farming systems in Mesoamerica. First, we evaluate the sustainability of three agricultural management systems in two contrasting weather years. We determined that during the first year that exposed heavy rains and moderate temperatures, low-input systems, which are based on the use of organic fertilizers and crop rotation, provided better results in terms of ecological indicators and equal results in terms of economic and social indicators than those achieved using a high chemical input system. In the second year, which featured early frosts and a winter drought, productivity declined in all systems; however, the most diversified systems (in terms of the maize varieties grown and the sowing of other crops) more successfully resisted these climatic adversities. Second, we evaluate the farmers��� perception to determine the key drivers for achieving their sustainability and food and nutritional security. We determined that the key factors identified by farmers (landholding size and slope of cropland) exerted significant impacts on economic disparities but did not explain the malnutrition levels. We compared two contrasting hamlets according to their energy and protein supply, one namely Lim��n Timot�� (LT), which did not present food problems and Lim��n Pe��a Blanca (LP), which did exhibit food insecurity. The results showed that FNS is linked to sustainability, and it is primarily related to the sustainability attributes of self-reliance and equity. Although the more marginated and inaccessible community exhibited more food insecurity, food and nutritional security depend upon a complex array of self-sufficiency strategies that remain linked to individual household idiosyncrasies. Third, we evaluated the impact of farmer field schools for improving the sustainability and food security of peasant mountain systems. In order to appreciate the long-term impact, we studied three communities where FFSs were implemented eight, five and three years ago, respectively. We found that FFSs have a gradual impact, as the community that first implemented FFSs scores highest. The impact of FFSs was broad and long-lasting for indicators related to participation, access to basic services and conservation of natural resources. This study demonstrates the potential of FFSs, but more attention will have to be paid to critical indicators in order to scale up their potential in the future. We observed a direct relationship between the increase in agricultural production and the use of external inputs, which is a critical point for sustainable ideals.

Biometric authentication of users through iris by using key binding and similarity preserving hash functions = Autenticaci��n biom��trica de usuarios a trav��s del iris mediante la ocultaci��n de claves y funciones resumen que preservan la similitud

El extraordinario auge de las nuevas tecnolog��as de la informaci��n, el desarrollo de la Internet de las Cosas, el comercio electr��nico, las redes sociales, la telefon��a m��vil y la computaci��n y almacenamiento en la nube, han proporcionado grandes beneficios en todos los ��mbitos de la sociedad. Junto a ��stos, se presentan nuevos retos para la protecci��n y privacidad de la informaci��n y su contenido, como la suplantaci��n de personalidad y la p��rdida de la confidencialidad e integridad de los documentos o las comunicaciones electr��nicas. Este hecho puede verse agravado por la falta de una frontera clara que delimite el mundo personal del mundo laboral en cuanto al acceso de la informaci��n. En todos estos campos de la actividad personal y laboral, la Criptograf��a ha jugado un papel fundamental aportando las herramientas necesarias para garantizar la confidencialidad, integridad y disponibilidad tanto de la privacidad de los datos personales como de la informaci��n. Por otro lado, la Biometr��a ha propuesto y ofrecido diferentes t��cnicas con el fin de garantizar la autentificaci��n de individuos a trav��s del uso de determinadas caracter��sticas personales como las huellas d��ctilares, el iris, la geometr��a de la mano, la voz, la forma de caminar, etc. Cada una de estas dos ciencias, Criptograf��a y Biometr��a, aportan soluciones a campos espec��ficos de la protecci��n de datos y autentificaci��n de usuarios, que se ver��an enormemente potenciados si determinadas caracter��sticas de ambas ciencias se unieran con vistas a objetivos comunes. Por ello es imperativo intensificar la investigaci��n en estos ��mbitos combinando los algoritmos y primitivas matem��ticas de la Criptograf��a con la Biometr��a para dar respuesta a la demanda creciente de nuevas soluciones m��s t��cnicas, seguras y f��ciles de usar que potencien de modo simult��neo la protecci��n de datos y la identificac����n de usuarios. En esta combinaci��n el concepto de biometr��a cancelable ha supuesto una piedra angular en el proceso de autentificaci��n e identificaci��n de usuarios al proporcionar propiedades de revocaci��n y cancelaci��n a los ragos biom��tricos. La contribuci��n de esta tesis se basa en el principal aspecto de la Biometr��a, es decir, la autentificaci��n segura y eficiente de usuarios a trav��s de sus rasgos biom��tricos, utilizando tres aproximaciones distintas: 1. Dise��o de un esquema criptobiom��trico borroso que implemente los principios de la biometr��a cancelable para identificar usuarios lidiando con los problemas acaecidos de la variabilidad intra e inter-usuarios. 2. Dise��o de una nueva funci��n hash que preserva la similitud (SPHF por sus siglas en ingl��s). Actualmente estas funciones se usan en el campo del an��lisis forense digital con el objetivo de buscar similitudes en el contenido de archivos distintos pero similares de modo que se pueda precisar hasta qu�� punto estos archivos pudieran ser considerados iguales. La funci��n definida en este trabajo de investigaci��n, adem��s de mejorar los resultados de las principales funciones desarrolladas hasta el momento, intenta extender su uso a la comparaci��n entre patrones de iris. 3. Desarrollando un nuevo mecanismo de comparaci��n de patrones de iris que considera tales patrones como si fueran se��ales para compararlos posteriormente utilizando la transformada de Walsh-Hadarmard. Los resultados obtenidos son excelentes teniendo en cuenta los requerimientos de seguridad y privacidad mencionados anteriormente. Cada uno de los tres esquemas dise��ados han sido implementados para poder realizar experimentos y probar su eficacia operativa en escenarios que simulan situaciones reales: El esquema criptobiom��trico borroso y la funci��n SPHF han sido implementados en lenguaje Java mientras que el proceso basado en la transformada de Walsh-Hadamard en Matlab. En los experimentos se ha utilizado una base de datos de im��genes de iris (CASIA) para simular una poblaci��n de usuarios del sistema. En el caso particular de la funci��n de SPHF, adem��s se han realizado experimentos para comprobar su utilidad en el campo de an��lisis forense comparando archivos e im��genes con contenido similar y distinto. En este sentido, para cada uno de los esquemas se han calculado los ratios de falso negativo y falso positivo. ABSTRACT The extraordinary increase of new information technologies, the development of Internet of Things, the electronic commerce, the social networks, mobile or smart telephony and cloud computing and storage, have provided great benefits in all areas of society. Besides this fact, there are new challenges for the protection and privacy of information and its content, such as the loss of confidentiality and integrity of electronic documents and communications. This is exarcebated by the lack of a clear boundary between the personal world and the business world as their differences are becoming narrower. In both worlds, i.e the personal and the business one, Cryptography has played a key role by providing the necessary tools to ensure the confidentiality, integrity and availability both of the privacy of the personal data and information. On the other hand, Biometrics has offered and proposed different techniques with the aim to assure the authentication of individuals through their biometric traits, such as fingerprints, iris, hand geometry, voice, gait, etc. Each of these sciences, Cryptography and Biometrics, provides tools to specific problems of the data protection and user authentication, which would be widely strengthen if determined characteristics of both sciences would be combined in order to achieve common objectives. Therefore, it is imperative to intensify the research in this area by combining the basics mathematical algorithms and primitives of Cryptography with Biometrics to meet the growing demand for more secure and usability techniques which would improve the data protection and the user authentication. In this combination, the use of cancelable biometrics makes a cornerstone in the user authentication and identification process since it provides revocable or cancelation properties to the biometric traits. The contributions in this thesis involve the main aspect of Biometrics, i.e. the secure and efficient authentication of users through their biometric templates, considered from three different approaches. The first one is designing a fuzzy crypto-biometric scheme using the cancelable biometric principles to take advantage of the fuzziness of the biometric templates at the same time that it deals with the intra- and inter-user variability among users without compromising the biometric templates extracted from the legitimate users. The second one is designing a new Similarity Preserving Hash Function (SPHF), currently widely used in the Digital Forensics field to find similarities among different files to calculate their similarity level. The function designed in this research work, besides the fact of improving the results of the two main functions of this field currently in place, it tries to expand its use to the iris template comparison. Finally, the last approach of this thesis is developing a new mechanism of handling the iris templates, considering them as signals, to use the Walsh-Hadamard transform (complemented with three other algorithms) to compare them. The results obtained are excellent taking into account the security and privacy requirements mentioned previously. Every one of the three schemes designed have been implemented to test their operational efficacy in situations that simulate real scenarios: The fuzzy crypto-biometric scheme and the SPHF have been implemented in Java language, while the process based on the Walsh-Hadamard transform in Matlab. The experiments have been performed using a database of iris templates (CASIA-IrisV2) to simulate a user population. The case of the new SPHF designed is special since previous to be applied i to the Biometrics field, it has been also tested to determine its applicability in the Digital Forensic field comparing similar and dissimilar files and images. The ratios of efficiency and effectiveness regarding user authentication, i.e. False Non Match and False Match Rate, for the schemes designed have been calculated with different parameters and cases to analyse their behaviour.

Corn Liberalization in Mexico: The Effects of Neoliberal Policies on Campesino Food Security

Mexico has a long history of structuralized violence against its most vulnerable socioeconomic strata, the peasantry, also referred to as Campesinos. From the Spanish invasion, to the contemporary neoliberal development project, corn production has been intimately associated with disparate power relations both within Mexican society, and without, particularly in relations with the United States. This study sheds light on the incongruities of modernism implicit within neoliberal policy instruments such as Structural Adjustment Programs (SAP) and free trade agreements. It will demonstrate that while such policies benefit some, they principally exacerbate existing power disparities via disarticulated trade economics, subordinating rather than liberating Mexico's most vulnerable citizenry.

Agriculture and sustainable development: The role of small scale agriculture in obtaining food security

The international community has expressed a renewed interest in small scale agriculture and the role it plays in long-term food security in the face of climate change and population growth. This interest has led to a new development paradigm in which small scale producers are being brought into the global market. Undoubtedly, small scale agriculture should be pursued as a sustainable form of development which can contribute to poverty alleviation, environmental stewardship, and the preservation of genetic diversity. These unique contributions are inherently threatened by a system captured in the idea of the neoliberal food regime. The ability of small scale agriculture to uphold the goals of food security are dependent on recognition and preservation of these contributions.

A Cloud-based Framework for Security Analysis of Browser Extensions

In today's internet world, web browsers are an integral part of our day-to-day activities. Therefore, web browser security is a serious concern for all of us. Browsers can be breached in different ways. Because of the over privileged access, extensions are responsible for many security issues. Browser vendors try to keep safe extensions in their official extension galleries. However, their security control measures are not always effective and adequate. The distribution of unsafe extensions through different social engineering techniques is also a very common practice. Therefore, before installation, users should thoroughly analyze the security of browser extensions. Extensions are not only available for desktop browsers, but many mobile browsers, for example, Firefox for Android and UC browser for Android, are also furnished with extension features. Mobile devices have various resource constraints in terms of computational capabilities, power, network bandwidth, etc. Hence, conventional extension security analysis techniques cannot be efficiently used by end users to examine mobile browser extension security issues. To overcome the inadequacies of the existing approaches, we propose CLOUBEX, a CLOUd-based security analysis framework for both desktop and mobile Browser EXtensions. This framework uses a client-server architecture model. In this framework, compute-intensive security analysis tasks are generally executed in a high-speed computing server hosted in a cloud environment. CLOUBEX is also enriched with a number of essential features, such as client-side analysis, requirements-driven analysis, high performance, and dynamic decision making. At present, the Firefox extension ecosystem is most susceptible to different security attacks. Hence, the framework is implemented for the security analysis of the Firefox desktop and Firefox for Android mobile browser extensions. A static taint analysis is used to identify malicious information flows in the Firefox extensions. In CLOUBEX, there are three analysis modes. A dynamic decision making algorithm assists us to select the best option based on some important parameters, such as the processing speed of a client device and network connection speed. Using the best analysis mode, performance and power consumption are improved significantly. In the future, this framework can be leveraged for the security analysis of other desktop and mobile browser extensions, too.

Towards a new multilateral energy architecture? Security Policy Brief No. 39, October 2012

From climate change over peak oil to the geopolitical scramble for the Arctic, there are ample signs that a global energy crisis is unfolding. The sheer scale and urgency of this looming crisis calls for international coordination. Yet, even a cursory look at the existing international energy institutions leads to a sobering conclusion: the global energy governance architecture is weak, fragmented and incomplete. This policy brief discusses both the flaws in the multilateral energy architecture and some emerging ideas to strengthen it, such as the proposal for a Sustainable Energy Trade Agreement and the new American disclosure rules for the extractive sector.

Raiders of the Lost Art: Strategy-Making in Europe. Security Policy Brief No. 40, November 2012

Have Europeans lost the art of making grand strategy? In a reflection process initiated by Sweden, Poland, Italy and Spain, they are invited to rediscover it and draft a ���European Global Strategy���. This policy brief argues that what the EU needs most is a short set of priorities for collective action, to be reassessed for each term of the High Representative.

Safeguarding the EDTIB: the Case for Supervising non-EU FDI in the Defence Sector. Security Policy Brief No. 41, December 2012

It is time for the EU member states to start collectively supervising non-EU FDI in Europe���s defence industries and infrastructures. This should be a prudent element of the nascent EDTIB and a way to maintain European security by encouraging greater coordination between the national supervisory frameworks.

Brazilian perspectives on the changing global order and security challenges. CEPS Working Document No. 376, February 2013

This study analyses the current picture and prospects for EU���Brazil relations in the political and security arenas. As actors experiencing relevant changes, albeit in different directions in their respective international status quo, the EU and Brazil have found some common ground for convergence at the macro level on some structural issues, such as the normative framework of a changing global order, the striving for a multipolar world and the relevance and desirability of multilateralism. At the same time, it is argued that they differ significantly as to the strategies pursued in the attainment of those shared interests, resulting in competing, or eventually divergent, policy preferences when addressing specific issues and developments at the international level, limiting the prospects for a deep mutual commitment and engagement in political and security dynamics at the global level.

Europe���s most wanted? Recalibrating Trust in the European Arrest Warrant System. CEPS Paper Liberty and Security in Europe 55/21 March 2013

This paper assesses the uses and misuses in the application of the European Arrest Warrant (EAW) system in the European Union. It examines the main quantitative results of this extradition system achieved between 2005 and 2011 on the basis of the existing statistical knowledge on its implementation at EU official levels. The EAW has been anchored in a high level of ���mutual trust��� between the participating states��� criminal justice regimes and authorities. This reciprocal confidence, however, has been subject to an increasing number of challenges resulting from its practical application, presenting a dual conundrum: 1. Principle of proportionality: Who are the competent judicial authorities cooperating with each other and ensuring that there are sufficient impartial controls over the necessity and proportionality of the decisions on the issuing and execution of EAWs? 2. Principle of division of powers: How can criminal justice authorities be expected to handle different criminal judicial traditions in what is supposed to constitute a ���serious��� or ���minor��� crime in their respective legal settings and ���who��� is ultimately to determine (divorced from political considerations) when is it duly justified to make the EAW system operational? It is argued that the next generation of the EU���s criminal justice cooperation and the EAW need to recognise and acknowledge that the mutual trust premise upon which the European system has been built so far is no longer viable without devising new EU policy stakeholders��� structures and evaluation mechanisms. These should allow for the recalibration of mutual trust and mistrust in EU justice systems in light of the experiences of the criminal justice actors and practitioners having a stake in putting the EAW into daily effect. Such a ���bottom-up approach��� should be backed up with the best impartial and objective evaluation, an improved system of statistical collection and an independent qualitative assessment of its implementation. This should be placed as the central axis of a renewed EAW framework which should seek to better ensure the accountability, impartial (EU-led) scrutiny and transparency of member states��� application of the EAW in light of the general principles and fundamental rights constituting the foundations of the European system of criminal justice cooperation.