Herramienta para la detección de contenido oculto en redes P2P

This end of degree project is based on two key parts, steganography and P2P networks. The term steganography comes from the Greek words steganos, which means hidden, and graphos, which means writing. Therefore, the term, literally, can be interpreted as hidden writing. From a more general point of view the term steganography can be interpreted as the study of the set of techniques and processes that enable to hide information embedding it in other information. Informally, steganography supplies the necessary tools to hide messages inside other messages (which only are supposed to be visible for the message's recipient). Although it may seem as a recent technique, steganography is a discipline used long since. Throughout history there have been many documented ways of exchanging messages hiding its existence, here are just a few: • Approximately toward the year 440 B.C, Aristágoras of Mileto (tyrant of Mileto's city), used one of his slaves to provoke a riot against the Persian. The way to exchange the message was the following: first, Aristagoras shaved the head of one of his slaves and tattooed him the message that wanted to send in the slave's scalp. Done that, he just needed to wait for the slave's hair to grow back. When this happened, he sent the slave to meet the receiver of the message. Shaving the slave´s head he was able to access it. • During Middle Age in Europe a method consisting in superimposing a template (which used to be paper or wood), called Cardan grille and which contained a series of holes on a write was developed. • During World War II some rather curious methods were developed to hide messages. One of them was to use the characters "j", "i", "t" and "f" to send messages in Morse code within a message, written on a microfilm, which was apparently normal. As can be observed the characters "j" and "i" could be used to transmit the "short beeps" message, while the characters "f" and "t" could be used to transmit the "long beep" message. • Another method that was developed during the World War II was possible thanks to the technological advances in photography. Thanks to these advances, the micropoints technology was developed. This technology allows reducing a photograph to a point size so that adding these images in a text is possible. If these images are hidden as punctuation marks (points, commas ...), they are almost undetectable. • Finally, among the most widely used methods throughout history are invisible inks. Text messages can be written with these inks. To have access to these messages is necessary to heat the paper support on which the message is written. The most common inks used can be: lemon juice, milk, urine, ammonia salt... in general, substances containing large amounts of carbon in its composition.Ingeniería Informátic

Impact of the start-up process on the microbial communities in biocathodes for electrosynthesis

[EN]This study elucidates the impact of the start-up strategies on the microbial communities that evolve on the biofilm of a biocathode. Using reductive start-up potentials and a highly diverse inoculum, this start-up failed to produce any biofilm. When a less species richness inoculum from an anaerobic environment was used with the same reductive initial potential, a specialised biofilm was formed and a highly productive biocathode was developed in terms of acetic acid and also current production. However, using oxidative start-up potential led to rapid electroactive biofilm development, although the final composition of the biofilm was highly dependent on the inoculum used. So, using the diverse RM inoculum, a final specialised biofilm grew on the electrode, also giving high acetate and current generation. However, when using the less species richness AD inoculum, it was found that a nonspecialised biofilm was developed and lower acetic acid production was found. Importantly, a higher specialisation of the biofilm leads to an improvement in acetate generation, probably due to lowered influence of undesirable secondary methabolic pathways. Moreover, it has been shown that the coupling of H2 producing bacteria and acetic acid bacteria play an important role in acetate productionSIThis research was possible thanks to the financial support of the ‘Ministerio de Economía y Competitividad’ project ref: CTQ2015-68925-R, cofinanced by FEDER funds. Raúl Mateos thanks the Spanish ‘Ministerio de Educación, Cultura y Deporte’ for the FPU Grant (FPU14/01573). Ana Sotres thanks the regional ‘Junta de Castilla y León’ for the postdoctoral contract associated with project ref: LE060U16

Integrating microbial electrochemical technologies with anaerobic digestion to accelerate propionate degradation

[EN] The aim of this study is to evaluate the integration of microbial electrochemical technologies (MET) with anaerobic digestion (AD) to overcome AD limitations caused by propionate accumulation. The study focuses on understanding to what extent the inoculum impacts on the behaviour of the integrated systems (AD-MET) from the perspective of propionate degradation, methane production and microbial population dynamics. Three different inocula were used: two from environmental sources (anaerobic sludge and river sediment) and another one from a pre-enriched electroactive consortium adapted to propionate degradation. Contrary to expectations, the reactor inoculated with the pre-enriched consortium was not able to maintain its initial good performance in the long run, and the bioelectrochemical activity collapsed after three months of operation. On the other hand, the reactor inoculated with anaerobic sludge, although it required a relatively longer time to produce any observable current, was able to maintain an electrogenic activity operation (0.8 A m−2), whilst showcasing the positive contribution of AD-MET integration into tackling propionate accumulation and enhancing methane yield (338 mL gCOD−1). However, it must also be highlighted that from a purely energetic point of view the AD-MET was not favourable.SIMinisterio de Economía y CompetitividadJunta de Castilla y LeónEnte Regional de la Energía de Castilla y Leo

Study of materials and manufacturing technologies for an antenna distribution network in Ka band

A study for selecting the technology and material manufacturing for the distribution network of a low profile antenna in Ka band in order to provide Internet connection in commercial aircrafts through satellite link. It is presented the general structure of the network focused in new printed technologies for high frequencies such as Substrate Integrated Waveguide or Ridge Gap Waveguide. Simulated results for different dielectric materials in terms of transmission losses are provided

Design proposal for ridge waveguide and comparison with other technologies in Ka to W bands

A design procedure of Ridge Gap Waveguide technology is proposed. The simulated results for Ka-band and above are compared with other technologies like Substrate Integrated Waveguide, microstrip or classical waveguide in terms of transmission losses

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Comparison of Activation Methods for 3D-Printed Electrodes for Microbial Electrochemical Technologies

Supplementary Materials: The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/app12010275/s1, Figure S1. Current density profiles of two successive cycles at the end of a 60 days period that allowed for the development of a stable biofilm; Table S1: Fitted parameters to EC 1 (DMF and acetone electrodes); Table S2: Fitted parameters to EC 2 (control and electrochemical-treated electrodes); Figure S2. Equivalent circuits for abiotic electrode essays’ modellization.1) DMF and acetone 2) Control and electrochemical treatment.[EN] Three-dimensional printing could provide flexibility in the design of a new generation of electrodes to be used in microbial electrochemical technologies (MET). In this work, we demonstrate the feasibility of using polylactic acid (PLA)/graphene—a common 3D-printing material—to build custom bioelectrodes. We also show that a suitable activation procedure is crucial to achieve an acceptable electrochemical performance (plain PLA/graphene bioanodes produce negligible amounts of current). Activation with acetone and dimethylformamide resulted in current densities similar to those typically observed in bioanodes built with more conventional materials (about 5 Am−2). In addition, the electrodes thus activated favored the proliferation of electroactive bacteria.SIMinisterio de Economía y CompetitividadEnte Regional de la Energía de Castilla y LeonThis research was funded by “Ministerio de Economía y Competitividad (Gobierno de España) grant number: PID2020-115948RB-I00 (MINECO/FEDER, EU) and “Ente Regional de la Energía de Castilla y Leon”, grant number: EREN_2019_L3_ULE

Electrodos de carbono modificados por electro-reducción de óxido de grafeno para su aplicación en sistemas bio-electroquímicos

Modificación de electrodos de carbono con óxido de grafeno para la mejora del rendimiento en sistemas bioelectroquímicos. This research was supported by the regional government ‘Junta de Castilla y León, Consejería de Educación’, project reference: LE060U16, co-financed by FEDER fund

Organizaciones autónomas descentralizadas (DAOs) para economía colaborativa utilizando Blockchain

Este trabajo consiste en la creación de un modelo de Organización Autónoma Descentralizada (DAO) sobre Blockchain para sociedades con un estilo de economía colaborativa. A diferencia de otras aplicaciones nuestro trabajo está realizado de manera que, no sólo se pueda aplicar a un tipo de organización como el que hemos hecho de ejemplo (Guerrilla developers) sino que, está hecho para que sirva de modelo para cualquier organización que tenga un sistema de roles en los que se necesite hacer ciertos méritos para poder ascender en la organización. La aplicación está desarrollada sobre Aragon, que es un framework que trabaja sobre Ethereum. El uso de Aragon facilita la creación de estas organizaciones ya que cuenta con funcionalidades que son de gran ayuda como sistema de votación o gestión de tokens. Ethereum es una plataforma digital que utiliza la tecnología de cadena de bloques (blockchain) desarrollada para Bitcoin y expande su uso a distintos tipos de aplicaciones. El uso de este tipo de tecnología evita la necesidad de que todo el sistema de gestión este centralizado y que se deposite la confianza en una sola autoridad

Noncommutative strong maximals and almost uniform convergence in several directions

Our first result is a noncommutative form of Jessen/Marcinkiewicz/Zygmund theorem for the maximal limit of multiparametric martingales or ergodic means. It implies bilateral almost uniform convergence with initial data in the expected Orlicz spaces. A key ingredient is the introduction of the $L_p$-norm of the $\limsup$ of a sequence of operators as a localized version of a $\ell_\infty/c_0$-valued $L_p$-space. In particular, our main result gives a strong $L_1$-estimate for the $\limsup$, as opposed to the usual weak $L_{1,\infty}$-estimate for the $\sup$. Let $\mathcal{L} \mathbf{F}_2$ denote the free group algebra and consider the free Poisson semigroup generated by the usual length function. It is an open problem to determine the largest class inside $L_1(\mathcal{L} \mathbf{F}_2)$ for which this semigroup converges to the initial data. Currently, the best known result is $L \log^2 L(\mathcal{L} \mathbf{F}_2)$. We improve this by adding to it the operators in $L_1(\mathcal{L} \mathbf{F}_2)$ spanned by words without signs changes. Contrary to other related results in the literature, this set has exponential growth. The proof relies on our estimates for the noncommutative $\limsup$ together with new transference techniques. We also establish a noncommutative form of C\'ordoba/Feffermann/Guzm\'an inequality for the strong maximal. More precisely, a weak $(\Phi,\Phi)$ inequality for noncommutative multiparametric martingales and $\Phi(s) = s (1 + \log_+ s)^{2 + \varepsilon}$. This logarithmic power is an $\varepsilon$-perturbation of the expected optimal one. The proof combines a refinement of Cuculescu's construction with a quantum probabilistic interpretation of de Guzm\'an's argument. The commutative form of our argument gives the simplest known proof of this classical inequality. A few interesting consequences are derived for Cuculescu's projections.Comment: 38 page