Joint Optimization for Social Content Delivery in Wireless Networks

Over the last decade, success of social networks has significantly reshaped how people consume information. Recommendation of contents based on user profiles is well-received. However, as users become dominantly mobile, little is done to consider the impacts of the wireless environment, especially the capacity constraints and changing channel. In this dissertation, we investigate a centralized wireless content delivery system, aiming to optimize overall user experience given the capacity constraints of the wireless networks, by deciding what contents to deliver, when and how. We propose a scheduling framework that incorporates content-based reward and deliverability. Our approach utilizes the broadcast nature of wireless communication and social nature of content, by multicasting and precaching. Results indicate this novel joint optimization approach outperforms existing layered systems that separate recommendation and delivery, especially when the wireless network is operating at maximum capacity. Utilizing limited number of transmission modes, we significantly reduce the complexity of the optimization. We also introduce the design of a hybrid system to handle transmissions for both system recommended contents ('push') and active user requests ('pull'). Further, we extend the joint optimization framework to the wireless infrastructure with multiple base stations. The problem becomes much harder in that there are many more system configurations, including but not limited to power allocation and how resources are shared among the base stations ('out-of-band' in which base stations transmit with dedicated spectrum resources, thus no interference; and 'in-band' in which they share the spectrum and need to mitigate interference). We propose a scalable two-phase scheduling framework: 1) each base station obtains delivery decisions and resource allocation individually; 2) the system consolidates the decisions and allocations, reducing redundant transmissions. Additionally, if the social network applications could provide the predictions of how the social contents disseminate, the wireless networks could schedule the transmissions accordingly and significantly improve the dissemination performance by reducing the delivery delay. We propose a novel method utilizing: 1) hybrid systems to handle active disseminating requests; and 2) predictions of dissemination dynamics from the social network applications. This method could mitigate the performance degradation for content dissemination due to wireless delivery delay. Results indicate that our proposed system design is both efficient and easy to implement.

NETCODE: an XOR-based warning dissemination scheme for vehicular wireless networks

The next generation of vehicles will be equipped with automated Accident Warning Systems (AWSs) capable of warning neighbouring vehicles about hazards that might lead to accidents. The key enabling technology for these systems is the Vehicular Ad-hoc Networks (VANET) but the dynamics of such networks make the crucial timely delivery of warning messages challenging. While most previously attempted implementations have used broadcast-based data dissemination schemes, these do not cope well as data traffic load or network density increases. This problem of sending warning messages in a timely manner is addressed by employing a network coding technique in this thesis. The proposed NETwork COded DissEmination (NETCODE) is a VANET-based AWS responsible for generating and sending warnings to the vehicles on the road. NETCODE offers an XOR-based data dissemination scheme that sends multiple warning in a single transmission and therefore, reduces the total number of transmissions required to send the same number of warnings that broadcast schemes send. Hence, it reduces contention and collisions in the network improving the delivery time of the warnings. The first part of this research (Chapters 3 and 4) asserts that in order to build a warning system, it is needful to ascertain the system requirements, information to be exchanged, and protocols best suited for communication between vehicles. Therefore, a study of these factors along with a review of existing proposals identifying their strength and weakness is carried out. Then an analysis of existing broadcast-based warning is conducted which concludes that although this is the most straightforward scheme, loading can result an effective collapse, resulting in unacceptably long transmission delays. The second part of this research (Chapter 5) proposes the NETCODE design, including the main contribution of this thesis, a pair of encoding and decoding algorithms that makes the use of an XOR-based technique to reduce transmission overheads and thus allows warnings to get delivered in time. The final part of this research (Chapters 6--8) evaluates the performance of the proposed scheme as to how it reduces the number of transmissions in the network in response to growing data traffic load and network density and investigates its capacity to detect potential accidents. The evaluations use a custom-built simulator to model real-world scenarios such as city areas, junctions, roundabouts, motorways and so on. The study shows that the reduction in the number of transmissions helps reduce competition in the network significantly and this allows vehicles to deliver warning messages more rapidly to their neighbours. It also examines the relative performance of NETCODE when handling both sudden event-driven and longer-term periodic messages in diverse scenarios under stress caused by increasing numbers of vehicles and transmissions per vehicle. This work confirms the thesis' primary contention that XOR-based network coding provides a potential solution on which a more efficient AWS data dissemination scheme can be built.

Uma API criptográfica para aplicações embarcadas

This document presents GEmSysC, an unified cryptographic API for embedded systems. Software layers implementing this API can be built over existing libraries, allowing embedded software to access cryptographic functions in a consistent way that does not depend on the underlying library. The API complies to good practices for API design and good practices for embedded software development and took its inspiration from other cryptographic libraries and standards. The main inspiration for creating GEmSysC was the CMSIS-RTOS standard, which defines an unified API for embedded software in an implementation-independent way, but targets operating systems instead of cryptographic functions. GEmSysC is made of a generic core and attachable modules, one for each cryptographic algorithm. This document contains the specification of the core of GEmSysC and three of its modules: AES, RSA and SHA-256. GEmSysC was built targeting embedded systems, but this does not restrict its use only in such systems – after all, embedded systems are just very limited computing devices. As a proof of concept, two implementations of GEmSysC were made. One of them was built over wolfSSL, which is an open source library for embedded systems. The other was built over OpenSSL, which is open source and a de facto standard. Unlike wolfSSL, OpenSSL does not specifically target embedded systems. The implementation built over wolfSSL was evaluated in a Cortex- M3 processor with no operating system while the implementation built over OpenSSL was evaluated on a personal computer with Windows 10 operating system. This document displays test results showing GEmSysC to be simpler than other libraries in some aspects. These results have shown that both implementations incur in little overhead in computation time compared to the cryptographic libraries themselves. The overhead of the implementation has been measured for each cryptographic algorithm and is between around 0% and 0.17% for the implementation over wolfSSL and between 0.03% and 1.40% for the one over OpenSSL. This document also presents the memory costs for each implementation.

Panoptikum Bildung – Impulse zur demokratiepolitischen Bildung. Radiosendungen als Beitrag zu zivilgesellschaftlichem Engagement

Die Radiosendung Panoptikum Bildung versteht sich als Medium kritischer Berichterstattung und versucht sozialpolitische Phänomene durch sachliche Informationen aufzubereiten. Die einzelnen Radiobeiträge beleuchten bildungsrelevante Themen aus einem kritischen Blickwinkel, bieten umfassende Hintergrundinformationen und binden FachexpertInnen mit ein. Credo ist: Information statt Infotainment, Gespräch statt Floskeln, Wissensvermittlung anstelle von Talkshowformaten und Dialog statt Konfrontation. In diesem Beitrag, der sich auf bisher unveröffentlichte Jahresberichte der Radiosendereihe stützt, werden das Entstehen und die Leitgedanken sowie die Inhalte und Anliegen einzelner Radiobeiträge vor dem Hintergrund von Oskar Negts theoretischen Überlegungen zu Demokratie und Bildung beschrieben und reflektiert. (DIPF/Orig.)

Hydrothermal-vent alvinellid polychaete dispersal in the eastern Pacific .1. Influence of vent site distribution, bottom currents, and biological patterns

Deep-sea hydrothermal-vent habitats are typically linear, discontinuous, and short-lived. Some of the vent fauna such as the endemic polychaete family Alvinellidae are thought to lack a planktotrophic larval stage and therefore not to broadcast-release their offspring. The genetic evidence points to exchanges on a scale that seems to contradict this type of reproductive pattern. However, the rift valley may topographically rectify the bottom currents, thereby facilitating the dispersal of propagules between active vent sites separated in some cases by 10s of kilometers or more along the ridge axis. A propagule flux model based on a matrix of intersite distances, long-term current-meter data, and information on the biology and ecology of Alvinellidae was developed to test this hypothesis. Calculations of the number of migrants exchanged between two populations per generation (N-m) allowed comparisons with estimates obtained from genetic studies. N, displays a logarithmic decrease with increasing dispersal duration and reaches the critical value of 1 after 8 d when the propagule Aux model was run in standard conditions. At most, propagule traveling time cannot reasonably exceed 15-30 d, according to the model, whereas reported distances between sites would require longer lasting dispersal abilities. Two nonexclusive explanations are proposed. First, some aspects of the biology of Alvinellidae have been overlooked and long-distance dispersal does occur. Second, such dispersal never occurs in Alvinellidae, but the spatial-temporal dynamics of vent sites over geological timescales allows short-range dispersal processes to maintain gene flow.

A VOICE OF THEIR OWN: MUSIC AND SOCIAL COHESION IN TURKISH ALEVI LIFE

This dissertation examines the role that music has played in the expression of identity and revitalization of culture of the Alevis in Turkey, since the start of their sociocultural revival movement in the late 1980s. Music is central to Alevi claims of ethnic and religious difference—singing and playing the bağlama (Turkish folk lute) constitutes an expressive practice in worship and everyday life. Based on research conducted from 2012 to 2014, I investigate and present Alevi music through the lens of discourses on the construction of identity as a social and musical process. Alevi musicians perform a revived repertoire of the ritual music and folk songs of Anatolian bards and dervish-lodge poets that developed over several centuries. Contemporary media and performance contexts have blurred former distinctions between sacred and secular, yet have provided new avenues to build community in an urban setting. I compare music performances in the worship services of urban and small-town areas, and other community events such as devotional meetings, concerts, clubs, and broadcast and social media to illustrate the ways that participation—both performing and listening—reinforces identity and solidarity. I also examine the influence of these different contexts on performers’ musical choices, and the power of music to evoke a range of responses and emotional feelings in the participants. Through my investigation I argue that the Alevi music repertoire is not only a cultural practice but also a symbol of power and collective action in their struggle for human rights and self-determination. As Alevis have faced a redefined Turkish nationalism that incorporates Sunni Muslim piety, this music has gained even greater potency in their resistance to misrecognition as a folkloric, rather than a living, tradition.

Le sous titrage en français des séries télévisées américaines : normes linguistiques et pratiques professionnelles

De nos jours, les séries télévisées américaines représentent une part incontournable de la culture populaire, à tel point que plusieurs traductions audiovisuelles coexistent au sein de la francophonie. Outre le doublage qui permet leur diffusion à la télévision, elles peuvent être sous titrées jusqu’à trois fois soit, en ordre chronologique : par des fans sur Internet; au Québec, pour la vente sur DVD en Amérique du Nord; et en France, pour la vente sur DVD en Europe. Pourtant, bien que ces trois sous titrages répondent aux mêmes contraintes linguistiques (celles de la langue française) et techniques (diffusion au petit écran), ils diffèrent dans leur traitement des dialogues originaux. Nous établissons dans un premier temps les pratiques à l’œuvre auprès des professionnels et des amateurs. Par la suite, l’analyse des traductions ainsi que le recours à un corpus comparable de séries télévisées françaises et québécoises permettent d’établir les normes linguistiques (notamment eu égard à la variété) et culturelles appliquées par les différents traducteurs et, subsidiairement, de définir ce que cache l’appellation « Canadian French ». Cette thèse s’inscrit dans le cadre des études descriptives et sociologiques. Nous y décrivons la réalité professionnelle des traducteurs de l’audiovisuel et l’influence que les fansubbers exercent non seulement sur la pratique professionnelle, mais aussi sur de nouvelles méthodes de formation de la prochaine génération de traducteurs. Par ailleurs, en étudiant plusieurs traductions d’une même œuvre, nous démontrons que les variétés de français ne sauraient justifier, à elles seules, la multiplication de l’offre en sous titrage, vu le faible taux de différences purement linguistiques.

Energy Cooperation in Energy Harvesting Communication Systems

In energy harvesting communications, users transmit messages using energy harvested from nature. In such systems, transmission policies of the users need to be carefully designed according to the energy arrival profiles. When the energy management policies are optimized, the resulting performance of the system depends only on the energy arrival profiles. In this dissertation, we introduce and analyze the notion of energy cooperation in energy harvesting communications where users can share a portion of their harvested energy with the other users via wireless energy transfer. This energy cooperation enables us to control and optimize the energy arrivals at users to the extent possible. In the classical setting of cooperation, users help each other in the transmission of their data by exploiting the broadcast nature of wireless communications and the resulting overheard information. In contrast to the usual notion of cooperation, which is at the signal level, energy cooperation we introduce here is at the battery energy level. In a multi-user setting, energy may be abundant in one user in which case the loss incurred by transferring it to another user may be less than the gain it yields for the other user. It is this cooperation that we explore in this dissertation for several multi-user scenarios, where energy can be transferred from one user to another through a separate wireless energy transfer unit. We first consider the offline optimal energy management problem for several basic multi-user network structures with energy harvesting transmitters and one-way wireless energy transfer. In energy harvesting transmitters, energy arrivals in time impose energy causality constraints on the transmission policies of the users. In the presence of wireless energy transfer, energy causality constraints take a new form: energy can flow in time from the past to the future for each user, and from one user to the other at each time. This requires a careful joint management of energy flow in two separate dimensions, and different management policies are required depending on how users share the common wireless medium and interact over it. In this context, we analyze several basic multi-user energy harvesting network structures with wireless energy transfer. To capture the main trade-offs and insights that arise due to wireless energy transfer, we focus our attention on simple two- and three-user communication systems, such as the relay channel, multiple access channel and the two-way channel. Next, we focus on the delay minimization problem for networks. We consider a general network topology of energy harvesting and energy cooperating nodes. Each node harvests energy from nature and all nodes may share a portion of their harvested energies with neighboring nodes through energy cooperation. We consider the joint data routing and capacity assignment problem for this setting under fixed data and energy routing topologies. We determine the joint routing of energy and data in a general multi-user scenario with data and energy transfer. Next, we consider the cooperative energy harvesting diamond channel, where the source and two relays harvest energy from nature and the physical layer is modeled as a concatenation of a broadcast and a multiple access channel. Since the broadcast channel is degraded, one of the relays has the message of the other relay. Therefore, the multiple access channel is an extended multiple access channel with common data. We determine the optimum power and rate allocation policies of the users in order to maximize the end-to-end throughput of this system. Finally, we consider the two-user cooperative multiple access channel with energy harvesting users. The users cooperate at the physical layer (data cooperation) by establishing common messages through overheard signals and then cooperatively sending them. For this channel model, we investigate the effect of intermittent data arrivals to the users. We find the optimal offline transmit power and rate allocation policy that maximize the departure region. When the users can further cooperate at the battery level (energy cooperation), we find the jointly optimal offline transmit power and rate allocation policy together with the energy transfer policy that maximize the departure region.

El uso de la documentación audiovisual en los programas informativos diarios de televisión

[SPA] El objetivo de la investigación es conocer cual es la aportación cuantitativa y cualitativa de la documentación audiovisual en la información que ofrece diariamente la televisión. El marco temporal de la investigación de campo se sitúa en los años 1993 y 1994, en un marco geográfico constituido por los canales que emiten en el estado español. El estudio parte de una aproximación teórica a la documentación periodística, a la documentación audiovisual y a los estudios sobre la comunicación de masas, y lleva a cabo una investigación de campo en tres áreas: 1) Análisis de programas informativos diarios de seis cadenas de televisión (ETB, TVE, Canal Sur, TV3, Antena 3 y Canal+), a través de tres muestras independientes. 2) Análisis de las peticiones de documentación audiovisual realizadas desde las redacciones de programas informativos a los servicios de documentación. 3) Estudio de las funciones, tareas, estructura y organización de los servicios de documentación de televisión, basado en encuestas, visitas y entrevistas. En anexo se ofrece el análisis detallado de 620 noticias, así como la información de los centros de documentación. La investigación concluye afirmando que la documentación audiovisual es uno de los elementos constitutivos de la información de actualidad, tanto por su presencia cuantitativa (más de un 40% de las noticias emitidas la emplean), como por su aportación cualitativa y su utilización generalizada en todas las secciones informativas. Las conclusiones señalan que la importancia de las noticias incide positivamente en el empleo de documentación audiovisual, sintetizan las funciones de esta documentación y las características específicas de su uso. Confirman el carácter de retroalimentación de la documentación informativa en televisión. Señalan un empleo de esta documentación como documentación puramente visual. Y afirman que la documentación audiovisual, además de contribuir en la producción, coadyuva a la calidad de los programas informativos, en la medida en que facilita la tarea de ofrecer una información más completa y contextualizada.

Direito da religião

This dissertation stands out the religious and social role of Christian religious minorities in Portuguese society, where the vast majority of the believers profess the Catholic faith. This work serves to demystify the widespread prejudice against minorities and clarify its place in the religious phenomenon in Portugal. We intend to define the concept of Religion, missing in the Portuguese legislation, framing it in Portuguese constitutional history, which allows us to evaluate the relations State/Catholic Church and State/religious minorities, since Liberalism. We attempt to measure how the legal system accepts the religious phenomenon and how to deal with religious diversity, according to the principle of religious freedom postulated in the Constitution of the Portuguese Republic. It is also our intention to relate the concepts of sect and religious minority, which tendentiously are misunderstood. In order to understand the underlying dynamics of religious minorities, we take the example of the Portuguese Evangelical Alliance, which we monitored closely throughout the investigation. We will give some space for a small analysis of the state and social discrimination experienced by the minorities. With this work we can conclude in general that Portugal, despite its weak religious diversity, has a good advance on the religious freedom. The Portuguese State has made a remarkable effort to cooperate with the churches, an effort that must be continued in order to fill some gaps found, particularly in the absence of legislation regarding the criminalization of religious discrimination and competence of the Committee on Religious Freedom in case of a possible complaint. We prove similarly that there is also a special attention to the Catholic Church in the composition of the Committee on Religious Freedom and the Committee Broadcast Time of Religious Confessions. In the end, we prove that the society is the major source of discrimination against minorities.

Estudio académico para la producción y realización de una radio revista informativa, que comunique aspectos relevantes, de la parroquia de Ricaurte

El siguiente proyecto Radial realizado en la Parroquia Ricaurte hizo posible que los problemas de la parroquia sean escuchados y conocidos a través del espacio ofrecido como Infórmate Ricaurte un medio radial. Para la realización de este proyecto se tomaron puntos de vista, una serie de objetivos que dió paso a la resolución de los mismos, y fueron resolviéndose y tomando prioridad según la necesidad del producto a obtener. La necesidad de un medio de comunicación observada en la parroquia Ricaurte permitió desarrollar la idea de una radio revista “ Ricaurte Infórmate” junto con el apoyo del GAD parroquial y con los mismo moradores se puso en marcha el proyecto, cada paso de los objetivos se realizó en un consentimiento grupal. Con temas exclusivamente de sus alrededores, de la gente; se llevaron a cabo con el GAD (Gobierno Autónomo Descentralizado) Parroquial de la parroquia Ricaurte, siguiendo una metodología descriptiva y cuali-cuantitativa. Con el único propósito de realizar una radio Revista Informativa dirigidaa la Parroquia. Durante este proyecto se cumplen todos los objetivos planteados con resultado favorecedores gracias a la buena aceptación de todos los participantes y otros moradores de la Parroquia. Se complementó con la tabulación según las estrategias planteadas, lo cual permitió realizar y poner en marcha la transmisión del programa.

Plataforma digital de promoción y difusión musical

La industria musical a nivel mundial atraviesa una etapa de transición en varios procesos análogos a digitales y también de formatos físicos, como CD´s por mp3, esto representa para los artistas, nuevos caminos para generar ingresos y facilidades de introducción en la industria. En Ecuador, no se puede hablar de industria musical pues, lo que se ha desarrollado hasta este momento es solo una “escena musical” en donde los artistas intentan salir hacia mercados extranjeros utilizando diferentes herramientas de difusión tanto tradicionales como digitales, siendo pocos quienes consiguen este objetivo y además, rentabilidad en sus carreras musicales. El proyecto de intervención denominado “Construcción de una plataforma digital para la promoción y difusión de artistas musicales del género pop y rock de la ciudad de Cuenca, fundamentado en estrategias digitales creadas bajo el concepto ‘Mezcla de comunicaciones de marketing’, período 2015 -2016”, genera un modelo de negocio experimental basado en soportes digitales y estrategias de marketing y comunicación que benefician la difusión, venta y promoción de los artistas y su material musical. Todo esto con miras a aportar al desarrollo de la escena musical en Ecuador. El modelo de negocio experimental se basa en tres actividades que el Staff 4.32 (nombre de la plataforma digital) brindará como servicios a sus consumidores: 1) generador de contenidos con temáticas referentes a la industria musical, 2) distribución digital de música en tiendas online y 3) sello representante de artistas que forman parte del catálogo de músicos del Staff.

Simulazione di protocolli di gossip in territori a bassa connettività

I mondi di Smart City e Internet-of-Things si stanno ampliando notevolmente grazie all'evoluzione continua delle tecnologie. Tuttavia risultano escluse dall'ambito di interesse le zone rurali e decentralizzate perché spesso prive di un'infrastruttura di rete ben definita. A fronte di questo problema, i dispositivi che si trovano in queste zone potrebbero auto-organizzarsi per comunicare instaurando collegmenti di tipo peer-to-peer e utilizzando protocolli di disseminazione di informazioni basati su gossip. In questa tesi sono trattate le seguenti questioni e mediante alcune simulazioni al calcolatore sono riprodotti alcuni scenari per valutare le prestazioni degli algoritmi di Gossip with Fixed Probability e Conditional Broadcast e la diffusione delle informazioni tra i nodi all'interno di una rete creata in maniera opportunistica.

Hardware processors for pairing-based cryptography

Bilinear pairings can be used to construct cryptographic systems with very desirable properties. A pairing performs a mapping on members of groups on elliptic and genus 2 hyperelliptic curves to an extension of the finite field on which the curves are defined. The finite fields must, however, be large to ensure adequate security. The complicated group structure of the curves and the expensive field operations result in time consuming computations that are an impediment to the practicality of pairing-based systems. The Tate pairing can be computed efficiently using the ɳT method. Hardware architectures can be used to accelerate the required operations by exploiting the parallelism inherent to the algorithmic and finite field calculations. The Tate pairing can be performed on elliptic curves of characteristic 2 and 3 and on genus 2 hyperelliptic curves of characteristic 2. Curve selection is dependent on several factors including desired computational speed, the area constraints of the target device and the required security level. In this thesis, custom hardware processors for the acceleration of the Tate pairing are presented and implemented on an FPGA. The underlying hardware architectures are designed with care to exploit available parallelism while ensuring resource efficiency. The characteristic 2 elliptic curve processor contains novel units that return a pairing result in a very low number of clock cycles. Despite the more complicated computational algorithm, the speed of the genus 2 processor is comparable. Pairing computation on each of these curves can be appealing in applications with various attributes. A flexible processor that can perform pairing computation on elliptic curves of characteristic 2 and 3 has also been designed. An integrated hardware/software design and verification environment has been developed. This system automates the procedures required for robust processor creation and enables the rapid provision of solutions for a wide range of cryptographic applications.

Mídia e educação

O presente trabalho buscou analisar o atual discurso jornalístico sobre educação, no contexto da internet como nova mídia, levando em conta os efeitos das mensagens difundidas e no que contribuem para o processo histórico e cultural do meio em que vivemos, trazendo como estudo de caso, uma pesquisa realizada no Portal do Jornal Zero Hora – um dos veículos de comunicação com maior circulação do Brasil. Buscando empreender uma pesquisa bem sucedida, e, como uma forma de nortear o que nos propusemos a desenvolver no papel de pesquisadores, definimos perguntas que nos orientaram no decorrer deste trabalho, entre elas: Como se dá o discurso educativo no Portal Zero Hora? Como o discurso jornalístico no Portal Zero Hora contribui para disseminar assuntos relacionados à educação? As informações veiculadas no Portal Zero Hora contribuem para a formação contínua do professor? A partir do arcabouço teórico e metodológico planejado, partimos para a pesquisa empírica que se utilizou de uma vasta revisão bibliográfica e de técnicas e métodos quantitativos e qualitativos, buscando respaldo nas Teorias do Jornalismo, as quais contribuíram para o sucesso dos resultados. Das teorias, nos alicerçamos da Análise de Conteúdo e Análise de Discurso, Teoria do Agenda-Setting e Teoria de Knowledge Gap, com base na fundamentação teórica de autores. A investigação concluiu que o meio online exerce um papel importante na difusão de notícias da área educacional, contribuindo na construção da realidade social e no desenvolvimento e enriquecimento cognitivo, cultural e informativo das pessoas em sociedade. Constatamos que a divulgação de informações na mídia online colabora na formação de processos comunicacionais, possibilitando reflexões que incentivam às transformações no contexto da educação.