Secure transmission of information by digital chaotic signals

Protecting signals is one of the main tasks in information transmission. A large number of different methods have been employed since many centuries ago. Most of them have been based on the use of certain signal added to the original one. When the composed signal is received, if the added signal is known, the initial information may be obtained. The main problem is the type of masking signal employed. One possibility is the use of chaotic signals, but they have a first strong limitation: the need to synchronize emitter and receiver. Optical communications systems, based on chaotic signals, have been proposed in a large number of papers. Moreover, because most of the communication systems are digital and conventional chaos generators are analogue, a conversion analogue-digital is needed. In this paper we will report a new system where the digital chaos is obtained from an optically programmable logic structure. This structure has been employed by the authors in optical computing and some previous results in chaotic signals have been reported. The main advantage of this new system is that an analogue-digital conversion is not needed. Previous works by the authors employed Self-Electrooptical Effect Devices but in this case more conventional structures, as semiconductor laser amplifiers, have been employed. The way to analyze the characteristics of digital chaotic signals will be reported as well as the method to synchronize the chaos generators located in the emitter and in the receiver.

Digital light beam deflector with liquid cristal (1980)

In this letter , we report a new method for óptical switching based on the electro-optical properties of liquid crystal materials and, in particular, of the nematic type. The basis of this new method is the use of twisted wedge structure that has not been reported before elsewhere. In the past several years , great efforts in integrated optics have been made to develop optical switching devices with fast speed by using electro-optic, acousto-optic or magneto -optic materials. A mechanically operated óptical switch made of grade-index rod 1enses and e1ectromagnets has been proposed too . Switches of this kind include one input and two output waveguides and, depending on the app1ied voltage, one incident light on the switch exits either in one or another of the two output waveguides.

Sensing Aeropolis. Urban air monitoring devices in Madrid, 2006-2010

Esta tesis examina las implicaciones técnicas, políticas y espaciales del aire urbano, y en concreto, de la calidad del aire, para tenerlo en cuenta desde una perspectiva arquitectónica. En oposición a formas de entender el aire como un vacío o como una metáfora, este proyecto propone abordarlo desde un acercamiento material y tecnológico, trayendo el entorno al primer plano y reconociendo sus múltiples agencias. Debido a la escasa bibliografía detectada en el campo de la arquitectura, el objetivo es construir un marco teórico-analítico para considerar el aire urbano. Para ello el trabajo construye Aeropolis, una metáfora heurística que describe el ensamblaje sociotecnico de la ciudad. Situada en la intersección de determinadas ramas de la filosofía de la cultura, los estudios sobre ciencia y tecnología y estudios feministas de la ciencia este nuevo paisaje conceptual ofrece una metodología y herramientas para abordar el objeto de estudio desde distintos ángulos. Estas herramientas metodológicas han sido desarrolladas en el contexto específico de Madrid, ciudad muy contaminada cuyo aire ha sido objeto de controversias políticas y sociales, y donde las políticas y tecnologías para reducir sus niveles no han sido exitosas. Para encontrar una implicación alternativa con el aire esta tesis propone un método de investigación de agentes invisibles a partir del análisis de sus dispositivos epistémicos. Se centra, en concreto, en los instrumentos que miden, visualizan y comunican la calidad del aire, proponiendo que no sólo lo representan, sino que son también instrumentos que diseñan el aire y la ciudad. La noción de “sensing” (en castellano medir y sentir) es expandida, reconociendo distintas prácticas que reconstruyen el aire de Madrid. El resultado de esta estrategia no es sólo la ampliación de los espacios desde los que relacionarnos con el aire, sino también la legitimación de prácticas existentes fuera de contextos científicos y administrativos, como por ejemplo prácticas relacionadas con el cuerpo, así como la redistribución de agencias entre más actores. Así, esta tesis trata sobre toxicidad, la Unión Europea, producción colaborativa, modelos de computación, dolores de cabeza, kits DIY, gases, cuerpos humanos, salas de control, sangre o políticos, entre otros. Los dispositivos que sirven de datos empíricos sirven como un ejemplo excepcional para investigar infraestructuras digitales, permitiendo desafiar nociones sobre Ciudades Inteligentes. La tesis pone especial atención en los efectos del aire en el espacio público, reconociendo los procesos de invisibilización que han sufrido sus infraestructuras de monitorización. Para terminar se exponen líneas de trabajo y oportunidades para la arquitectura y el diseño urbano a través de nuevas relaciones entre infraestructuras urbanas, el medio construido, espacios domésticos y públicos y humanos y no humanos, para crear nuevas ecologías políticas urbanas (queer). ABSTRACT This thesis examines the technical, political and spatial implications of urban air, and more specifically "air quality", in order to consider it from an architectural perspective. In opposition to understandings of the air either as a void or as a metaphor, this project proposes to inspect it from a material and technical approach, bringing the background to the fore and acknowledging its multiple agencies. Due to the scarce bibliography within the architectural field, its first aim is to construct a theoretical and analytical framework from which to consider urban air. For this purpose, the work attempts the construction of Aeropolis, a heuristic metaphor that describes the city's aero socio-material assemblage. Located at the intersection of certain currents in cultural philosophy, science and technology studies as well as feminist studies in technoscience, this framework enables a methodology and toolset to be extracted in order to approach the subject matter from different angles. The methodological tools stemming from this purpose-built framework were put to the test in a specific case study: Madrid, a highly polluted city whose air has been subject to political and social controversies, and where no effective policies or technologies have been successful in reducing its levels of pollution. In order to engage with the air, the thesis suggests a method for researching invisible agents by examining the epistemic devices involved. It locates and focuses on the instruments that sense, visualise and communicate urban air, claiming that they do not only represent it, but are also instruments that design the air and the city. The notion of "sensing" is then expanded by recognising different practices which enact the air in Madrid. The work claims that the result of this is not only the opening up of spaces for engagement but also the legitimisation of existing practices outside science and policymaking environments, such as embodied practices, as well as the redistribution of agency among more actors. So this is a thesis about toxicity, the European Union, collaborative production, scientific computational models, headaches, DIY kits, gases, human bodies, control rooms, blood, or politicians, among many others. The devices found throughout the work serve as an exceptional substrate for an investigation of digital infrastructures, enabling to challenge Smart City tropes. There is special attention paid to the effects of the air on the public space, acknowledging the silencing processes these infrastructures have been subjected to. Finally there is an outline of the opportunities arising for architecture and urban design when taking the air into account, to create new (queer) urban political ecologies between the air, urban infrastructures, the built environment, public and domestic spaces, and humans and more than humans.

Desarrollo de un entorno inteligente en el contexto del hogar digital

A lo largo de las últimas décadas el desarrollo de la tecnología en muy distintas áreas ha sido vertiginoso. Su propagación a todos los aspectos de nuestro día a día parece casi inevitable y la electrónica de consumo ha invadido nuestros hogares. No obstante, parece que la domótica no ha alcanzado el grado de integración que cabía esperar hace apenas una década. Es cierto que los dispositivos autónomos y con un cierto grado de inteligencia están abriéndose paso de manera independiente, pero el hogar digital, como sistema capaz de abarcar y automatizar grandes conjuntos de elementos de una vivienda (gestión energética, seguridad, bienestar, etc.) no ha conseguido extenderse al hogar medio. Esta falta de integración no se debe a la ausencia de tecnología, ni mucho menos, y numerosos son los estudios y proyectos surgidos en esta dirección. Sin embargo, no ha sido hasta hace unos pocos años que las instituciones y grandes compañías han comenzado a prestar verdadero interés en este campo. Parece que estamos a punto de experimentar un nuevo cambio en nuestra forma de vida, concretamente en la manera en la que interactuamos con nuestro hogar y las comodidades e información que este nos puede proporcionar. En esa corriente se desarrolla este Proyecto Fin de Grado, con el objetivo de aportar un nuevo enfoque a la manera de integrar los diferentes dispositivos del hogar digital con la inteligencia artificial y, lo que es más importante, al modo en el que el usuario interactúa con su vivienda. Más concretamente, se pretende desarrollar un sistema capaz de tomar decisiones acordes al contexto y a las preferencias del usuario. A través de la utilización de diferentes tecnologías se dotará al hogar digital de cierta autonomía a la hora de decidir qué acciones debe llevar a cabo sobre los dispositivos que contiene, todo ello mediante la interpretación de órdenes procedentes del usuario (expresadas de manera coloquial) y el estudio del contexto que envuelve al instante de ejecución. Para la interacción entre el usuario y el hogar digital se desarrollará una aplicación móvil mediante la cual podrá expresar (de manera conversacional) las órdenes que quiera dar al sistema, el cual intervendrá en la conversación y llevará a cabo las acciones oportunas. Para todo ello, el sistema hará principalmente uso de ontologías, análisis semántico, redes bayesianas, UPnP y Android. Se combinará información procedente del usuario, de los sensores y de fuentes externas para determinar, a través de las citadas tecnologías, cuál es la operación que debe realizarse para satisfacer las necesidades del usuario. En definitiva, el objetivo final de este proyecto es diseñar e implementar un sistema innovador que se salga de la corriente actual de interacción mediante botones, menús y formularios a los que estamos tan acostumbrados, y que permita al usuario, en cierto modo, hablar con su vivienda y expresarle sus necesidades, haciendo a la tecnología un poco más transparente y cercana y aproximándonos un poco más a ese concepto de hogar inteligente que imaginábamos a finales del siglo XX. ABSTRACT. Over the last decades the development of technology in very different areas has happened incredibly fast. Its propagation to all aspects of our daily activities seems to be inevitable and the electronic devices have invaded our homes. Nevertheless, home automation has not reached the integration point that it was supposed to just a few decades ago. It is true that some autonomic and relatively intelligent devices are emerging, but the digital home as a system able to control a large set of elements from a house (energy management, security, welfare, etc.) is not present yet in the average home. That lack of integration is not due to the absence of technology and, in fact, there are a lot of investigations and projects focused on this field. However, the institutions and big companies have not shown enough interest in home automation until just a few years ago. It seems that, finally, we are about to experiment another change in our lifestyle and how we interact with our home and the information and facilities it can provide. This Final Degree Project is developed as part of this trend, with the goal of providing a new approach to the way the system could integrate the home devices with the artificial intelligence and, mainly, to the way the user interacts with his house. More specifically, this project aims to develop a system able to make decisions, taking into account the context and the user preferences. Through the use of several technologies and approaches, the system will be able to decide which actions it should perform based on the order interpretation (expressed colloquially) and the context analysis. A mobile application will be developed to enable the user-home interaction. The user will be able to express his orders colloquially though out a conversational mode, and the system will also participate in the conversation, performing the required actions. For providing all this features, the system will mainly use ontologies, semantic analysis, Bayesian networks, UPnP and Android. Information from the user, the sensors and external sources will be combined to determine, through the use of these technologies, which is the operation that the system should perform to meet the needs of the user. In short, the final goal of this project is to design and implement an innovative system, away from the current trend of buttons, menus and forms. In a way, the user will be able to talk to his home and express his needs, experiencing a technology closer to the people and getting a little closer to that concept of digital home that we imagined in the late twentieth century.

Sistema de autenticación accesible para el hogar digital

El Hogar Digital Accesible (HDA) de la ETSIST nace con el propósito de acercar las nuevas Tecnologías de la Información a las personas que precisan de necesidades concretas de accesibilidad y usabilidad, dotándoles de herramientas que les permitan aumentar su calidad de vida, confort, seguridad y autonomía. El entorno del HDA consta de elementos de control para puertas, persianas, iluminación, agua o gas, sensores de temperatura, incendios, gas, sistemas de climatización, sistemas de entretenimiento y sistemas de seguridad tales como detectores de presencia y alarmas. Todo ello apoyado sobre una arquitectura de red que proporciona una pasarela residencial y un acceso a banda ancha. El objetivo principal de este PFG ha sido el desarrollo de un sistema de autenticación para el Hogar Digital Accesible de bajo coste. La idea de integrar un sistema de autenticación en el HDA, surge de la necesidad de proteger de accesos no deseados determinados servicios disponibles dentro de un ámbito privado. Algunos de estos servicios pueden ser tales como el acceso a la lectura de los mensajes disponibles en el contestador automático, el uso de equipos multimedia, la desconexión de alarmas de seguridad o simplemente la configuración de ambientes según el usuario que esté autenticado (intensidad de luz, temperatura de la sala, etc.). En el desarrollo han primado los principios de accesibilidad, usabilidad y seguridad necesarios para la creación de un entorno no invasivo, que permitiera acreditar la identidad del usuario frente al sistema HDA. Se ha planteado como posible solución, un sistema basado en el reconocimiento de un trazo realizado por el usuario. Este trazo se usará como clave de cara a validar a los usuarios. El usuario deberá repetir el trazado que registró en el sistema para autenticarse. Durante la ejecución del presente PFG, se justificará la elección de este mecanismo de autenticación frente a otras alternativas disponibles en el mercado. Para probar la aplicación, se ha podido contar con dos periféricos de distintas gamas, el uDraw creado para la PS3 que se compone de una tableta digitalizadora y un lápiz que permite recoger los trazos realizados por el usuario de forma inalámbrica y la tableta digitalizadora Bamboo de Wacom. La herramienta desarrollada permite a su vez, la posibilidad de ser usada por otro tipo de dispositivos como es el caso del reloj con acelerómetro de 3 ejes de Texas Instruments Chronos eZ430 capaz de trasladar los movimientos del usuario al puntero de un ratón. El PFG se encuentra dividido en tres grandes bloques de flujo de trabajo. El primero se centra en el análisis del sistema y las tecnologías que lo componen, incluyendo los distintos algoritmos disponibles para realizar la autenticación basada en reconocimiento de patrones aplicados a imágenes que mejor se adaptan a las necesidades del usuario. En el segundo bloque se recoge una versión de prueba basada en el análisis y el diseño UML realizado previamente, sobre la que se efectuaron pruebas de concepto y se comprobó la viabilidad del proyecto. El último bloque incluye la verificación y validación del sistema mediante pruebas que certifican que se han alcanzado los niveles de calidad necesarios para la consecución de los objetivos planteados, generando finalmente la documentación necesaria. Como resultado del trabajo realizado, se ha obtenido un sistema que plantea una arquitectura fácilmente ampliable lograda a través del uso de técnicas como la introspección, que permiten separar la lógica de la capa de negocio del código que la implementa, pudiendo de forma simple e intuitiva sustituir código mediante ficheros de configuración, lo que hace que el sistema sea flexible y escalable. Tras la realización del PFG, se puede concluir que el producto final obtenido ha respondido de forma satisfactoria alcanzando los niveles de calidad requeridos, siendo capaz de proporcionar un sistema de autenticación alternativo a los convencionales, manteniendo unas cotas de seguridad elevadas y haciendo de la accesibilidad y el precio sus características más reseñables. ABSTRACT. Accessible Digital Home (HDA) of the ETSIST was created with the aim of bringing the latest information and communications technologies closer to the people who has special needs of accessibility and usability increasing their quality of life, comfort, security and autonomy. The HDA environment has different control elements for doors, blinds, lighting, water or gas, temperature sensors, fire protection systems, gas flashover, air conditioning systems, entertainments systems and security systems such as intruders detectors and alarms. Everything supported by an architecture net which provides a broadband residential services gateway. The main goal of this PFG was the development of a low-cost authentication system for the Accessible Digital Home. The idea of integrating an authentication system on the HDA, stems from the need to safeguard certain private key network resources from unauthorized access. Some of said resources are the access to the answering machine messages, the use of multimedia devices, the alarms deactivation or the parameter settings for each environment as programmed by the authenticated user (light intensity, room temperature, etc.). During the development priority was given to concepts like accessibility, usability and security. All of them necessary to create a non invasive environment that allows the users to certify their identity. A system based on stroke pattern recognition, was considered as a possible solution. This stroke is used as a key to validate users. The user must repeat the stroke that was saved on the system to validate access. The selection of this authentication mechanism among the others available options will be justified during this PFG. Two peripherals with different ranges were used to test the application. One of them was uDraw design for the PS3. It is wireless and is formed by a pen and a drawing tablet that allow us to register the different strokes drawn by the user. The other one was the Wacom Bamboo tablet, that supports the same functionality but with better accuracy. The developed tool allows another kind of peripherals like the 3-axes accelerometer digital wristwatch Texas Instruments Chronos eZ430 capable of transfering user movements to the mouse cursor. The PFG is divided by three big blocks that represent different workflows. The first block is focused on the system analysis and the technologies related to it, including algorithms for image pattern recognition that fits the user's needs. The second block describes how the beta version was developed based on the UML analysis and design previously done. It was tested and the viability of the project was verified. The last block contains the system verification and validation. These processes certify that the requirements have been fulfilled as well as the quality levels needed to reach the planned goals. Finally all the documentation has been produced. As a result of the work, an expandable system has been created, due to the introspection that provides the opportunity to separate the business logic from the code that implements it. With this technique, the code could be replaced throughout configuration files which makes the system flexible and highly scalable. Once the PFG has finished, it must therefore be concluded that the final product has been a success and high levels of quality have been achieved. This authentication tool gives us a low-cost alternative to the conventional ones. The new authentication system remains security levels reasonably high giving particular emphasis to the accessibility and the price.

Soluciones de control para el Hogar Digital Accesible

En este proyecto, se pretende obtener la solución óptima para el control del hogar digital accesible. Para ello, comenzaremos explicando el funcionamiento básico de un sistema dómotico, enumeraremos los diversos dispositivos que se utilizan en este tipo de automatizaciones, y comentaremos las diferentes posibilidades con respecto a la arquitectura del sistema. Para elegir la opción más adecuada, se realizará un pequeño estudio a acerca de cada una de las tecnologías existentes, protocolos cerrados, y abiertos, así como tecnologías inalámbricas o de bus. Se realizará un estudio con mayor profundidad del estándar KNX, ya que será una de las tecnologías elegidas finalmente para la realización del proyecto. Una vez elegido el estándar, hemos de centrarnos en las necesidades del recinto, para así poder empezar a definir cada uno de los elementos que incluiremos en nuestra instalación, sensores, actuadores, elementos de intercomunicación, procesadores y dispositivos de control. El siguiente paso consistiría en la programación de la vivienda, para ello hemos de tener previamente estructurados y definidos tanto el número de circuitos eléctricos, como la función que estos desempeñan dentro del recinto inteligente, es decir, accionamiento, regulación etc, para así poder asignar cada circuito a la salida correspondiente de su propio actuador. La vivienda se programará a través de ETS, software asociado a la marca KNX. Mediante este protocolo controlaremos, iluminación, motores, climatización y seguridad. Debido a los recursos limitados que ofrece KNX con respecto a la programación lógica de eventos y secuencias de acciones, y la necesidad de visualizar la interfaz gráfica de la vivienda se ha integrado un procesador. Considerando el deseo de integrar el control de un televisor en la vivienda, futuras ampliaciones y otros aspectos, el procesador integrado será de Crestron Electronics, marca correspondiente a un protocolo cerrado de automatización de sistemas, que cuenta con grandes avances en el control multimedia. Por tanto, la segunda parte de la programación se realizará mediante otros dos softwares diferentes, pertenecientes a la marca, Simple Windows se encargará de la programación lógica del sistema, mientras que Vision Tools creará la visualización. Por último, obtendremos las conclusiones necesarias, adjuntaremos un diagrama de conexionado, presupuesto de la instalación, planos y un pequeño manual de usuario. ABSTRACT. The aim of this project is to optimize the environment control of the Accesible Digital Home unit located in ETSIST - UPM, through different essays, valuing the domestic possibilities and the current interfaces. The tests will be carried out comparing different protocols and the possibilities of optimization that they offer to a Digital Home. Aspects such as: ease the communications with other systems, reliability, costs, long term maintenance of the installation, etc. After conducting trials protocol or most appropriate technology for the automation of the enclosure shall be elected. One Chosen the standard, we have to focus on the needs of the enclosure, so, to begin defining each of the elements included in our installation, sensors, actuators, elements intercom, processors and control devices. The next step is the programing of housing, for that we have previously structured and defined both the number of electrical circuits, as the role they play in the intelligent enclosure, that is, switching, dimming etc., in order to assign each circuit to the corresponding output of its own actuator. The house will be scheduled through ETS, software associated with the brand KNX. Through this protocol we will control, lighting, motors, air conditioning and security. Due to the limited resources available in KNX with respect logic programming of events and sequences of actions, and the need to display the graphical interface housing has been integrated processor belonging to the closed protocol or Crestron electronics brand. Finally, when we get the necessary conclusions, enclose a diagram of wiring, installation budget, planes and a small manual.

Interrogating Capabilities of IoT Devices

This research is supported by the UK Research Councils’ Digital Economy IT as a Utility Network+ (EP/K003569/1) and the dot.rural Digital Economy Hub (EP/G066051/1).

Interrogating Capabilities of IoT Devices

This research is supported by the UK Research Councils’ Digital Economy IT as a Utility Network+ (EP/K003569/1) and the dot.rural Digital Economy Hub (EP/G066051/1).

Trusted Tiny Things : Making Devices in Smart Cities More Transparent

Postprint

Oxide Semiconductors For Organic Opto-electronic Devices

Development of transparent oxide semiconductors (TOS) from Earth-abundant materials is of great interest for cost-effective thin film device applications, such as solar cells, light emitting diodes (LEDs), touch-sensitive displays, electronic paper, and transparent thin film transistors. The need of inexpensive or high performance electrode might be even greater for organic photovoltaic (OPV), with the goal to harvest renewable energy with inexpensive, lightweight, and cost competitive materials. The natural abundance of zinc and the wide bandgap ($sim$3.3 eV) of its oxide make it an ideal candidate. In this dissertation, I have introduced various concepts on the modulations of various surface, interface and bulk opto-electronic properties of ZnO based semiconductor for charge transport, charge selectivity and optimal device performance. I have categorized transparent semiconductors into two sub groups depending upon their role in a device. Electrodes, usually 200 to 500 nm thick, optimized for good transparency and transporting the charges to the external circuit. Here, the electrical conductivity in parallel direction to thin film, i.e bulk conductivity is important. And contacts, usually 5 to 50 nm thick, are optimized in case of solar cells for providing charge selectivity and asymmetry to manipulate the built in field inside the device for charge separation and collection. Whereas in Organic LEDs (OLEDs), contacts provide optimum energy level alignment at organic oxide interface for improved charge injections. For an optimal solar cell performance, transparent electrodes are designed with maximum transparency in the region of interest to maximize the light to pass through to the absorber layer for photo-generation, plus they are designed for minimum sheet resistance for efficient charge collection and transport. As such there is need for material with high conductivity and transparency. Doping ZnO with some common elements such as B, Al, Ga, In, Ge, Si, and F result in n-type doping with increase in carriers resulting in high conductivity electrode, with better or comparable opto-electronic properties compared to current industry-standard indium tin oxide (ITO). Furthermore, improvement in mobility due to improvement on crystallographic structure also provide alternative path for high conductivity ZnO TCOs. Implementing these two aspects, various studies were done on gallium doped zinc oxide (GZO) transparent electrode, a very promising indium free electrode. The dynamics of the superimposed RF and DC power sputtering was utilized to improve the microstructure during the thin films growth, resulting in GZO electrode with conductivity greater than 4000 S/cm and transparency greater than 90 %. Similarly, various studies on research and development of Indium Zinc Tin Oxide and Indium Zinc Oxide thin films which can be applied to flexible substrates for next generation solar cells application is presented. In these new TCO systems, understanding the role of crystallographic structure ranging from poly-crystalline to amorphous phase and the influence on the charge transport and optical transparency as well as important surface passivation and surface charge transport properties. Implementation of these electrode based on ZnO on opto-electronics devices such as OLED and OPV is complicated due to chemical interaction over time with the organic layer or with ambient. The problem of inefficient charge collection/injection due to poor understanding of interface and/or bulk property of oxide electrode exists at several oxide-organic interfaces. The surface conductivity, the work function, the formation of dipoles and the band-bending at the interfacial sites can positively or negatively impact the device performance. Detailed characterization of the surface composition both before and after various chemicals treatment of various oxide electrode can therefore provide insight into optimization of device performance. Some of the work related to controlling the interfacial chemistry associated with charge transport of transparent electrodes are discussed. Thus, the role of various pre-treatment on poly-crystalline GZO electrode and amorphous indium zinc oxide (IZO) electrode is compared and contrasted. From the study, we have found that removal of defects and self passivating defects caused by accumulation of hydroxides in the surface of both poly-crystalline GZO and amorphous IZO, are critical for improving the surface conductivity and charge transport. Further insight on how these insulating and self-passivating defects cause charge accumulation and recombination in an device is discussed. With recent rapid development of bulk-heterojunction organic photovoltaics active materials, devices employing ZnO and ZnO based electrode provide air stable and cost-competitive alternatives to traditional inorganic photovoltaics. The organic light emitting diodes (OLEDs) have already been commercialized, thus to follow in the footsteps of this technology, OPV devices need further improvement in power conversion efficiency and stable materials resulting in long device lifetimes. Use of low work function metals such as Ca/Al in standard geometry do provide good electrode for electron collection, but serious problems using low work-function metal electrodes originates from the formation of non-conductive metal oxide due to oxidation resulting in rapid device failure. Hence, using low work-function, air stable, conductive metal oxides such as ZnO as electrons collecting electrode and high work-function, air stable metals such as silver for harvesting holes, has been on the rise. Devices with degenerately doped ZnO functioning as transparent conductive electrode, or as charge selective layer in a polymer/fullerene based heterojunction, present useful device structures for investigating the functional mechanisms within OPV devices and a possible pathway towards improved air-stable high efficiency devices. Furthermore, analysis of the physical properties of the ZnO layers with varying thickness, crystallographic structure, surface chemistry and grain size deposited via various techniques such as atomic layer deposition, sputtering and solution-processed ZnO with their respective OPV device performance is discussed. We find similarity and differences in electrode property for good charge injection in OLEDs and good charge collection in OPV devices very insightful in understanding physics behind device failures and successes. In general, self-passivating surface of amorphous TCOs IZO, ZTO and IZTO forms insulating layer that hinders the charge collection. Similarly, we find modulation of the carrier concentration and the mobility in electron transport layer, namely zinc oxide thin films, very important for optimizing device performance.

A interoperabilidade nos sistemas de televisão digital interativa.

A televisão nos dias atuais tem sofrido inúmeras inovações tecnológicas nos campos das transmissões multimídia, qualidade audio-visual e diversidade de funcionalidades. Entretanto, esta essencialmente mantêm sua característica de fornecer informações de forma quase que instantânea à população. O ambiente atual da televisão digital é caracterizado pela coexistência de inúmeros dispositivos capazes de oferecerem uma experiência televisa, associando-se computadores pessoais, smartphones, tablets e outros eletrônicos de consumo. Ainda, pode se incluir a este cenário a disponibilidade de inúmeras redes de transporte de dados tais como a radiodifusão, satélite, cabo e redes em banda larga. Este cenário diversificado, em termos de dispositivos e redes, é denominado de cenário de televisão digital híbrida, a qual destaca-se a interação do expectador com os diversos dispositivos. Estes cenários, por sua vez, motivam o desenvolvimento de tecnologias que permitem o aperfeiçoamento da pervasividade e dos meios pelos os quais os aplicativos possam ser suportados em diferentes plataformas. Este trabalho propõe ambientes interoperáveis envolvendo a televisão digital interativa e outros eletrônicos de consumo, aos quais foram realizados estudos e experimentos para se observar diferentes técnicas de sincronização e comunicação entre plataformas de interatividade para a televisão digital híbrida. Os resultados apontam para a possibilidade de cenários interoperáveis envolvendo o uso de marcadores e também recursos de redes e serviços TCP/IP, levando em consideração a eficiência e eficácia nos diferentes métodos. Conclui-se que os resultados odem motivar o desenvolvimento de cenários diferenciados envolvendo a televisão digital interativa e dispositivos de segunda tela, o que incrementa a interatividade e as formas de entretenimento.

Measurement of wide frequency range structural microvibrations with a pocket digital camera and sub-pixel techniques

Analysis of vibrations and displacements is a hot topic in structural engineering. Although there is a wide variety of methods for vibration analysis, direct measurement of displacements in the mid and high frequency range is not well solved and accurate devices tend to be very expensive. Low-cost systems can be achieved by applying adequate image processing algorithms. In this paper, we propose the use of a commercial pocket digital camera, which is able to register more than 420 frames per second (fps) at low resolution, for accurate measuring of small vibrations and displacements. The method is based on tracking elliptical targets with sub-pixel accuracy. Our proposal is demonstrated at a 10 m distance with a spatial resolution of 0.15 mm. A practical application over a simple structure is given, and the main parameters of an attenuated movement of a steel column after an impulsive impact are determined with a spatial accuracy of 4 µm.

Measurement of wide frequency range structural microvibrations with a pocket digital camera and sub-pixel techniques

Analysis of vibrations and displacements is a hot topic in structural engineering. Although there is a wide variety of methods for vibration analysis, direct measurement of displacements in the mid and high frequency range is not well solved and accurate devices tend to be very expensive. Low-cost systems can be achieved by applying adequate image processing algorithms. In this paper, we propose the use of a commercial pocket digital camera, which is able to register more than 420 frames per second (fps) at low resolution, for accurate measuring of small vibrations and displacements. The method is based on tracking elliptical targets with sub-pixel accuracy. Our proposal is demonstrated at a 10 m distance with a spatial resolution of 0.15 mm. A practical application over a simple structure is given, and the main parameters of an attenuated movement of a steel column after an impulsive impact are determined with a spatial accuracy of 4 µm.

Análisis lexicométrico de la especificidad de la escritura digital del adolescente en WhatsApp

El artículo presenta una investigación en la que se analizan, desde una perspectiva lexicométrica y factorial, los aspectos lingüísticos y paralingüísticos más relevantes de la escritura digital síncrona del adolescente español, en uno de los programas de mensajería instantánea más utilizados en la actualidad (WhatsApp©). La escritura en soportes digitales móviles (smartphones y tabletas) es una de las actividades más realizadas en nuestra sociedad y constituye un componente esencial de la competencia comunicativa en la Sociedad de la Información. La comunicación digital forma parte de nuestras vidas y el análisis del uso comunicativo digital y ubicuo con dispositivos y programas tiene amplias repercusiones sociales, lingüísticas y pedagógicas. La investigación se ha contextualizado en una muestra de 417 conversaciones de WhatsApp de estudiantes de enseñanza secundaria, de entre 13 y 16 años, en cuatro provincias españolas. La metodología de investigación ha sido de corte cuantitativa para abordar el análisis lexicométrico del corpus lingüístico-digital con referencia a los elementos lingüísticos y paralingüísticos más relevantes; para, posteriormente, realizar el análisis de las correlaciones entre diferentes variables independientes que expliquen patrones lingüísticos y de uso en la escritura digital. Los resultados muestran que la escritura digital en este tipo de programas tiene una serie de características específicas ortotipográficas y audiovisuales condicionadas por variables de uso, el tamaño de la pantalla del dispositivo, la horas de conversación y la relación establecida entre los interlocutores.

Volumetric calibration of process vessels using digital computer techniques /

The paper describes a procedure for accurately and speedily calibrating tanks used for the chemical processing of nuclear materials. The procedure features the use of (1) precalibrated vessels certified to deliver known volumes of liquid, (2) calibrated linear measuring devices, and (3) a digital computer for manipulating data and producing printed calibration information. Calibration records of the standards are traceable to primary standards. Logic is incorporated in the computer program to accomplish curve fitting and perform the tests to accept or to reject the calibration, based on statistical, empirical, and report requirements. This logic is believed to be unique.