Extracción y análisis de características para identificación, agrupamiento y modificación de la fuente de imágenes generadas por dispositivos móviles

Tesis inédita de la Universidad Complutense de Madrid, Facultad de Informática, Departamento de Ingeniería del Software e Inteligencia Artificial, leída el 02/10/2017.Nowadays, digital images play an important role in our society. The presence of mobile devices with integrated cameras is growing at an unrelenting pace, resulting in the majority of digital images coming from this kind of device. Technological development not only facilitates the generation of these images, but also the malicious manipulation of them. Therefore, it is of interest to have tools that allow the device that has generated a certain digital image to be identified. The digital image source can be identified through the features that the generating device permeates it with during the creation process. In recent years most research on techniques for identifying the source has focused solely on traditional cameras. The forensic analysis techniques of digital images generated by mobile devices are therefore of particular importance since they have specific characteristics which allow for better results, and forensic techniques for digital images generated by another kind of device are often not valid. This thesis provides various contributions in two of the main research lines of forensic analysis, the field of identification techniques and the counter-forensics or attacks on these techniques. In the field of digital image source acquisition identification techniques, both closed and open scenarios are addressed. In closed scenarios, the images whose acquisition source are to be determined belong to a group of devices known a priori. Meanwhile, an open scenario is one in which the images under analysis belong to a set of devices that is not known a priori by the fo rensic analyst. In this case, the objective is not t he concrete image acquisition source identification, but their classification into groups whose images all belong to the same mobile device. The image clustering t echniques are of particular interest in real situations since in many cases the forensic analyst does not know a priori which devices have generated certain images. Firstly, techniques for identifying the device type (computer, scanner or digital camera of the mobile device) or class (make and model) of the image acquisition source in mobile devices are proposed, which are two relevant branches of forensic analysis of mobile device images. An approach based on different types of image features and Support Vector Machine as a classifier is presented. Secondly, a technique for the ident ification in open scenarios that consists of grouping digital images of mobile devices according to the acquisition source is developed, that is to say, a class-grouping of all input images is performed. The proposal is based on the combination of hierarchical grouping and flat grouping using the Sensor Pattern Noise. Lastly, in the area of att acks on forensic t echniques, topics related to the robustness of the image source identificat ion forensic techniques are addressed. For this, two new algorithms based on the sensor noise and the wavelet transform are designed, one for the destruction of t he image identity and another for its fo rgery. Results obtained by the two algorithms were compared with other tools designed for the same purpose. It is worth mentioning that the solution presented in this work requires less amount and complexity of input data than the tools to which it was compared. Finally, these identification t echniques have been included in a tool for the forensic analysis of digital images of mobile devices called Theia. Among the different branches of forensic analysis, Theia focuses mainly on the trustworthy identification of make and model of the mobile camera that generated a given image. All proposed algorithms have been implemented and integrated in Theia thus strengthening its functionality.Actualmente las imágenes digitales desempeñan un papel importante en nuestra sociedad. La presencia de dispositivos móviles con cámaras fotográficas integradas crece a un ritmo imparable, provocando que la mayoría de las imágenes digitales procedan de este tipo de dispositivos. El desarrollo tecnológico no sólo facilita la generación de estas imágenes, sino también la manipulación malintencionada de éstas. Es de interés, por tanto, contar con herramientas que permitan identificar al dispositivo que ha generado una cierta imagen digital. La fuente de una imagen digital se puede identificar a través de los rasgos que el dispositivo que la genera impregna en ella durante su proceso de creación. La mayoría de las investigaciones realizadas en los últimos años sobre técnicas de identificación de la fuente se han enfocado únicamente en las cámaras tradicionales. Las técnicas de análisis forense de imágenes generadas por dispositivos móviles cobran, pues, especial importancia, ya que éstos presentan características específicas que permiten obtener mejores resultados, no siendo válidas muchas veces además las técnicas forenses para imágenes digitales generadas por otros tipos de dispositivos. La presente Tesis aporta diversas contribuciones en dos de las principales líneas del análisis forense: el campo de las t écnicas de identificación de la fuente de adquisición de imágenes digitales y las contramedidas o at aques a est as técnicas. En el primer campo se abordan tanto los escenarios cerrados como los abiertos. En el escenario denominado cerrado las imágenes cuya fuente de adquisición hay que determinar pertenecen a un grupo de dispositivos conocidos a priori. Por su parte, un escenario abierto es aquel en el que las imágenes pertenecen a un conjunto de dispositivos que no es conocido a priori por el analista forense. En este caso el obj etivo no es la identificación concreta de la fuente de adquisición de las imágenes, sino su clasificación en grupos cuyas imágenes pertenecen todas al mismo dispositivo móvil. Las técnicas de agrupamiento de imágenes son de gran interés en situaciones reales, ya que en muchos casos el analist a forense desconoce a priori cuáles son los dispositivos que generaron las imágenes. En primer lugar se presenta una técnica para la identificación en escenarios cerrados del tipo de dispositivo (computador, escáner o cámara digital de dispositivo móvil) o la marca y modelo de la fuente en dispositivos móviles, que son dos problemáticas relevantes del análisis forense de imágenes digitales. La propuesta muestra un enfoque basado en distintos tipos de características de la imagen y en una clasificación mediante máquinas de soporte vectorial. En segundo lugar se diseña una técnica para la identificación en escenarios abiertos que consiste en el agrupamiento de imágenes digitales de dispositivos móviles según la fuente de adquisición, es decir, se realiza un agrupamiento en clases de todas las imágenes de ent rada. La propuesta combina agrupamiento jerárquico y agrupamiento plano con el uso del patrón de ruido del sensor. Por último, en el área de los ataques a las técnicas fo renses se tratan temas relacionados con la robustez de las técnicas forenses de identificación de la fuente de adquisición de imágenes. Se especifican dos algoritmos basados en el ruido del sensor y en la transformada wavelet ; el primero destruye la identidad de una imagen y el segundo falsifica la misma. Los resultados obtenidos por estos dos algoritmos se comparan con otras herramientas diseñadas para el mismo fin, observándose que la solución aquí presentada requiere de menor cantidad y complejidad de datos de entrada. Finalmente, estas técnicas de identificación han sido incluidas en una herramienta para el análisis forense de imágenes digitales de dispositivos móviles llamada Theia. Entre las diferentes ramas del análisis forense, Theia se centra principalmente en la identificación confiable de la marca y el modelo de la cámara móvil que generó una imagen dada. Todos los algoritmos desarrollados han sido implementados e integrados en Theia, reforzando así su funcionalidad.Depto. de Ingeniería de Software e Inteligencia Artificial (ISIA)Fac. de InformáticaTRUEunpu

PLC Networks with In-Band Full-Duplex Relays

Electromagnetic compatibility regulations impose strict transmit power spectral density limitations on power line communication (PLC) that limits the coverage it can provide.As a consequence, PLC networks, especially those used in smart grid neighborhood area networks, employ one or more repeaters/relays for coverage enhancement. In this paper, we analyze the use of in-band full-duplex (IBFD) operation in relaying for power line networks. We present analyses and numerical results to demonstrate the superior operating performance of IBFD-based relay-aided networks over the legacy half-duplex ones, and contrast the extent of performance enhancement we achieve over using direct links. To estimate such performance,we focus on orthogonal frequency division multiplexing (OFDM) systems, which are standard in PLC. We investigate both decode-and-forward and amplify-and-forward schemes of relaying fordual-hop power line links, and quantify the performance in terms of the attainable data rate under diverse realistic power linechannel and noise conditions. The fundamental analyses provided in this work guide the design of future IBFD relay-aided PLC networks across application scenarios.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Understanding the impact of line-of-sight in the ergodic spectral efficiency of cellular networks

In this paper we investigate the impact of lineof-sight (LoS) condition in the ergodic spectral efficiency of cellular networks. To achieve this goal, we have considered the kappa-mu shadowed model, which is a general model that provides an excellent fit to a wide set of propagation conditions. To overcome the mathematical complexity of the analysis, we have split the analysis between large and small-scale effects. Building on the proposed framework, we study a number of scenarios that range from heavily-fluctuating LoS to deterministic-LoS. Finally, we shed light on the interplay between fading severity and spectral efficiency by means of the amount of fading.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Evaluating Digital Cognitive Biomarkers as a Noninvasive Diagnostic Tool for Alzheimer\u27s Disease: Correlations with Classic CSF Biomarkers

Alzheimer\u27s Disease (AD) is a neurodegenerative disorder affecting over 35 million people. Early diagnosis and intervention are crucial for improving outcomes. Digital Cognitive Biomarkers (DCBs) offer a promising approach for early detection and disease management, quantifying cognitive processes of encoding and retrieval through a hierarchical Bayesian cognitive processing model using wordlist memory tests. We hypothesize that DCBs will correlate with classic AD cerebrospinal fluid (CSF) biomarkers (Aβ42, T-tau, p-tau) in patients with varying cognitive decline levels compared to healthy elderly controls. Using Alzheimer\u27s Disease Neuroimaging Initiative (ADNI) data and paired Pearson correlation coefficient analysis, our results support the hypothesis, indicating that DCBs correlate with CSF biomarkers and demonstrating their potential as a noninvasive diagnostic tool for AD. Furthermore, DCBs exhibited improved diagnostic accuracy compared to classic AD CSF biomarkers, as indicated by the area under the Receiver Operating Characteristic curve analysis. DCBs hold promise for monitoring disease progression, response to therapeutics, and identifying patients at earlier disease stages. Future research should validate these findings in diverse populations and conduct longitudinal studies to assess DCBs\u27 potential in tracking disease progression and treatment response. Integrating DCBs with other diagnostic approaches, such as neuroimaging, could enhance overall AD diagnosis accuracy and provide a comprehensive understanding of an individual\u27s cognitive health. In conclusion, DCBs may offer a valuable, noninvasive tool for early diagnosis and management of Alzheimer\u27s Disease, supporting the initial hypothesis

Toxoplasmosis congénita en España, presente y futuro

Publicación en formato PDF y EPUB.La toxoplasmosis es una enfermedad de alta prevalencia y distribución mundial que puede cursar de forma asintomática, aunque también puede ocasionar clínica grave en personas inmunocomprometidas e incluso ser mortal. Este libro compila información desde la perspectiva “Una salud” contando con la visión de diferentes profesionales implicados en el área: clínicos, epidemiólogos y microbiólogos, lo que proporciona una perspectiva altamente enriquecedora y de gran utilidad para todos aquellos profesionales interesados en esta temática.Introducción. Capítulo I: Toxoplasmosis congénita enfermedad de declaración obligatoria (EDO), situación actual en España. Capítulo II: Toxoplasma gondii, animales y medio ambiente: principales vías de transmisión. Capítulo III: Toxoplasmosis en la mujer, consulta pregestacional y prevención primaria. Capítulo IV: Tratamiento de la toxoplasmosis en la embarazada y de la infección fetal. Capítulo V: Aspectos generales de la infección congénita por Toxoplasma gondii en el niño. Capítulo VI: Toxoplasmosis ocular, consecuencias a largo plazo de la toxoplasmosis congénita. Capítulo VII: Proyecto REIV-TOXO: estudio de toxoplasmosis congénita en España. Capítulo VIII: El diagnóstico microbiológico convencional de la toxoplasmosis en la embarazada y niño. Capítulo IX: Diagnóstico de referencia de la toxoplasmosis y nuevas técnicas diagnósticas. Capítulo X: Inmunidad y vacunas frente a Toxoplasma gondii. Capítulo XI: El cribado de la toxoplasmosis congénita: Panorama internacional. Capítulo XII: ¿Cribado sí o cribado no?N

CPT1a gene expression reverses the inflammatory and anti-phagocytic effect of 7-ketocholesterol in RAW264.7 macrophages

Background: macrophage are specialized cells that contributes to the removal of detrimental contents via phagocytosis. Lipid accumulation in macrophages, whether from phagocytosis of dying cells or from circulating oxidized low-density lipoproteins, alters macrophage biology and functionality. It is known that carnitine palmitoyl transferase 1-a (CPT1a) gene encodes an enzyme involved in fatty acid oxidation and, therefore, lipid content. However, the potential of CPT1a to activate macrophage phagocytic function have not been elucidated. Methods: using a murine macrophage cell line, RAW264.7, we determine if intracellular accumulation of 7-ketocholesterol (7-KC) modulates macrophage phagocytic function through CPT1a gene expression. In addition, the effects of CPT1a genetic modification on macrophage phenotype and phagocytosis has been studied. Results: our results revealed that CPT1a gene expression decreased by the accumulation of 7-KC at the higher dose of 7-KC. This was concomitant with an impair ability to phagocytize bioparticles and an inflammatory phenotype. GW3965 treatment, which have shown to facilitate the efflux of cholesterol, eliminated the intracellular lipid droplets of 7-KC-laden macrophages, increased the gene expression of CPT1a, diminished the gene expression of the inflammatory marker iNOS and restored macrophage phagocytosis. Furthermore, CPT1a Knockdown per se was detrimental for macrophage phagocytosis whereas transcriptional activation of CPT1a heightened the uptake of bioparticles. Conclusions: altogether, our findings indicate that downregulation of CPT1a by lipid content modulates macrophage phagocytosis and inflammatory phenotype

Macrophage-derived Lipocalin-2 contributes to ischemic resistance mechanisms by protecting from renal injury

Renal ischemia-reperfusion injury triggers an inflammatory response associated to infiltrating macrophages which determines the further outcome of disease. Brown Norway rats are known to show endogenous resistance to ischemia-induced renal damage. By contrast, Sprague Dawley rats exhibit a higher susceptibility to ischemic injury. In order to ascertain cytoprotective mechanisms, we focused on the implication of lipocalin-2 protein in main resistance mechanisms in renal ischemia/reperfusion injury by using adoptive macrophage administration, genetically modified ex vivo either to overexpress or to knockdown lipocalin-2. In vitro experiments with bone marrow-derived macrophages both from Brown Norway rats and from Sprague Dawley rats under hypoxic conditions showed endogenous differences regarding cytokine and lipocalin-2 expression profile in the two strains. Most interestingly, we observed that macrophages of the resistant strain express significantly more lipocalin-2. In vivo studies showed that tubular epithelial cell apoptosis and renal injury significantly increased and reparative markers decreased in Brown Norway rats after injection of lipocalin-2-knockdown macrophages, while the administration of lipocalin-2-overexpressing cells significantly decreased Sprague Dawley susceptibility. These data point to a crucial role of macrophage-derived lipocalin-2 in endogenous cytoprotective mechanisms. We conclude that expression of lipocalin-2 in tissue-infiltrating macrophages is pivotal for kidney-intrinsic cytoprotective pathways during ischemia reperfusion injury