Les vidéos omnidirectionnelles, également appelées vidéos sphériques ou vidéos360°, sont des vidéos avec des pixels enregistrés dans toutes les directions de l’espace. Un utilisateur qui regarde un tel contenu avec un Casques de Réalité Virtuelle (CRV) peut sélectionner la partie de la vidéo à afficher, usuellement nommée viewport, en bougeant la tête. Pour se sentir totalement immergé à l’intérieur du contenu, l’utilisateur a besoin de voir au moins 90 viewports par seconde en 4K. Avec les technologies de streaming traditionnelles, fournir une telle qualité nécessiterait un débit de plus de100 Mbit s−1, ce qui est bien trop élevé. Dans cette thèse, je présente mes contributions pour rendre possible le streaming de vidéos omnidirectionnelles hautement immersives sur l’Internet. On peut distinguer six contributions : une proposition d’architecture de streaming viewport adaptatif réutilisant une partie des technologies existantes ; une extension de cette architecture pour des vidéos à six degrés de liberté ; deux études théoriques des vidéos à qualité spatiale non-homogène; un logiciel open source de manipulation des vidéos 360°; et un jeu d’enregistrements de déplacements d’utilisateurs regardant des vidéos 360°. / Omnidirectional videos, also denoted as spherical videos or 360° videos, are videos with pixels recorded from a given viewpoint in every direction of space. A user watching such an omnidirectional content with a Head Mounted Display (HMD) can select the portion of the videoto display, usually denoted as viewport, by moving her head. To feel high immersion inside the content a user needs to see viewport with 4K resolutionand 90 Hz frame rate. With traditional streaming technologies, providing such quality would require a data rate of more than 100 Mbit s−1, which is far too high compared to the median Internet access band width. In this dissertation, I present my contributions to enable the streaming of highly immersive omnidirectional videos on the Internet. We can distinguish six contributions : a viewport-adaptive streaming architecture proposal reusing a part of existing technologies ; an extension of this architecture for videos with six degrees of freedom ; two theoretical studies of videos with non homogeneous spatial quality ; an open-source software for handling 360° videos ; and a dataset of recorded users’ trajectories while watching 360° videos.

Le Big Data est maintenant la nouvelle ressource naturelle. Les architectures actuelles des environnements d'analyse des données massives sont constituées de trois couches: les flux de données sont acquis par la couche d’ingestion (e.g., Kafka) pour ensuite circuler à travers la couche de traitement (e.g., Flink) qui s’appuie sur la couche de stockage (e.g., HDFS) pour stocker des données agrégées ou pour archiver les flux pour un traitement ultérieur. Malheureusement, malgré les bénéfices potentiels apportés par les couches spécialisées (e.g., une mise en oeuvre simplifiée), déplacer des quantités importantes de données à travers ces couches spécialisées s’avère peu efficace: les données devraient être acquises, traitées et stockées en minimisant le nombre de copies. Cette thèse propose la conception et la mise en oeuvre d’une architecture unifiée pour l’ingestion et le stockage de flux de données, capable d'améliorer le traitement des applications Big Data. Cette approche minimise le déplacement des données à travers l’architecture d'analyse, menant ainsi à une amélioration de l’utilisation des ressources. Nous identifions un ensemble de critères de qualité pour un moteur dédié d’ingestion des flux et stockage. Nous expliquons l’impact des différents choix architecturaux Big Data sur la performance de bout en bout. Nous proposons un ensemble de principes de conception d’une architecture unifiée et efficace pour l’ingestion et le stockage des données. Nous mettons en oeuvre et évaluons le prototype KerA dans le but de gérer efficacement divers modèles d’accès: accès à latence faible aux flux et/ou accès à débit élevé aux flux et/ou objets. / Big Data is now the new natural resource. Current state-of-the-art Big Data analytics architectures are built on top of a three layer stack:data streams are first acquired by the ingestion layer (e.g., Kafka) and then they flow through the processing layer (e.g., Flink) which relies on the storage layer (e.g., HDFS) for storing aggregated data or for archiving streams for later processing. Unfortunately, in spite of potential benefits brought by specialized layers (e.g., simplified implementation), moving large quantities of data through specialized layers is not efficient: instead, data should be acquired, processed and stored while minimizing the number of copies. This dissertation argues that a plausible path to follow to alleviate from previous limitations is the careful design and implementation of a unified architecture for stream ingestion and storage, which can lead to the optimization of the processing of Big Data applications. This approach minimizes data movement within the analytics architecture, finally leading to better utilized resources. We identify a set of requirements for a dedicated stream ingestion/storage engine. We explain the impact of the different Big Data architectural choices on end-to-end performance. We propose a set of design principles for a scalable, unified architecture for data ingestion and storage. We implement and evaluate the KerA prototype with the goal of efficiently handling diverse access patterns: low-latency access to streams and/or high throughput access to streams and/or objects.

Submitted by Silvana Teresinha Dornelles Studzinski (sstudzinski) on 2016-10-11T16:17:07Z No. of bitstreams: 1 Mariana Rost_.pdf: 1317779 bytes, checksum: 370b5784aeb1c758e3cac3a3342974f6 (MD5) / Made available in DSpace on 2016-10-11T16:17:07Z (GMT). No. of bitstreams: 1 Mariana Rost_.pdf: 1317779 bytes, checksum: 370b5784aeb1c758e3cac3a3342974f6 (MD5) Previous issue date: 2016-08-30 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Esta dissertação focaliza as interações no CAM4, uma plataforma de pornografia live streaming, que consiste em transmissões ao vivo via webcam feitas por pessoas que se apresentam em atividade sexual com a possibilidade de quem as assiste interagir com elas e entre si através de um bate-papo alocado ao lado da caixa de vídeo. As práticas sexuais são negociadas por quem se apresenta e por quem assiste mediante o pagamento de gorjetas que operam desde metas distribuídas em torno de práticas particulares. Através de uma etnografia dos usos das mídias digitais, analiso o lugar da sexualidade, as noções de erotismo e a circulação de atributos de gênero nas negociações feitas nas transmissões do site. Interessa compreender as dinâmicas desse ambiente que produz e circula material pornográfico em um contexto de novas possibilidades tecnológicas e de busca pelo autêntico. Assim, identifico os mecanismos através dos quais a pornografia live streaming se organiza e como eles se articulam e concorrem na produção da diferença e das tecnologias de gênero e sexo. Também busco examinar como o dinheiro, os sex toys e os artefatos tecnológicos mobilizam formas específicas de obter prazer. Finalmente, procuro compreender como essa modalidade de pornografia pode se distribuir em investimentos políticos no campo das relações de gênero e sexualidade. / This Master's theses focuses on the negotiations on CAM4, a live streaming pornography website. This type of pornography consists of sharing live sexual activities over a webcam with the possibility of interaction between those who watch and the person on the video through an online chat beside the video box. The sexual practices are negotiated with tips that participants pay in exchange for specific activities. Through an ethnography about the use of digital media, I analyze the role of sexuality, the notions of eroticism and the circulation of gender attributes on the negotiations made in the transmissions on the website. I am interested in the dynamics of this environment that produces and circulates pornographic material in a context of the pursuit of the authenticity and new technological possibilities. Thus, I identify the mechanisms by which live streaming pornography is organized and how they compete in the production of difference as well as gender and sex technologies. I also aim to examine how money, sex toys and technological artifacts mobilize specific ways to have pleasure. Finally, I seek to understand how this type of pornography can be distributed in political actions in the field of gender relations and sexuality.

<p>Användandet av strömmande medier har ökat explosionsartat under de senaste åren. Oavsett om det sker märkbart för användaren eller inte använder sig gemene man i princip dagligen av någon form av tjänst som distribueras via strömmande medier över Internet. Det kan röra sig om allt från att lyssna på webbradio till att titta på videoklipp från nyhetsportaler eller sportsidor på Internet. </p><p>I denna rapports första del görs en kartläggning över strömmande medier rent generellt. Den läsekrets som inte är särskilt insatt i ämnet får reda på vad strömmande medier är, vilka aktörer som finns på marknaden, möjliga distributionssätt, historik med mera. </p><p>Fortsättningsvis kommer rapporten att behandla hur införandet av strömmande medier går till i teorin: hur distributionskedjan ser ut, vilka krav som konsument och producent ställer och hur man försöker att lösa problem som uppstår. Det senare leder vidare till en genomgång av bland annat streamingprotokoll, bredbandstekniker och komprimeringsstandarder för ljud och bild. </p><p>I rapportens senare del ges exempel på hur strömmande medier införs i praktiken. Här läggs speciellt fokus på användningsområdet sport och direktsändningar av sportevenemang. Konkreta exempel beskrivs och vi får även reda på hur det går till att genomföra en direktsänd sportsändning via strömmande medier. Som avslutning diskuteras tänkbara framtidscenarion och en utredning av en unikInternetsändning av en elitishockeymatch görs.</p>

I den här uppsatsen har faktorer för en ökad användaracceptans och diffusion av Video on demand(VOD)-tjänster identifierats med hjälp av en litteraturgenomgång av tidigare studier i acceptans och diffusion. Litteraturgenomgången ligger till grund för en lista av faktorer som gör en konsument mer villig att anamma en VOD-tjänst. Faktorerna har sedan utvärderas genom en kvantitativ undersökning med hjälp av en webbenkät. Resultatet blev i stor grad det som förväntat där det framgår att utbud och kostnad är de viktigaste faktorerna för en hög acceptans, men även andra faktorer kan spela in som användarvänlighet, kvalitet och sociala faktorer. / This paper has identified factors for increased user acceptance and diffusion of Video on Demand(VOD) services through a literature review of previous studies. The literature review was used to make a list of factors that make a consumer more willing to use a VOD service. The factors are then evaluated through a quantitative study using an online questionnaire. The result was to a large degree what was expected, which shows that content and cost are the main factors for a high acceptance, but other factors may play in as well such as ease-of-use, quality, and social factors.

Distributed stream-based applications manage large quantities of data and exhibit unique production and consumption patterns that set them apart from general-purpose applications. This dissertation examines possible ways of creating more efficient memory management schemes. Specifically, it looks at the memory reclamation problem. It takes advantage of special traits of streaming applications to extend the definition of the garbage collection problem for those applications and include not only data items that are not reachable but also items that have no effect on the final outcome of the application. Streaming applications typically fully process only a portion of the data, and resources directed towards the remaining data items (i.e., those that dont affect the final outcome) can be viewed as wasted resources that should be minimized. Two complementary approaches are suggested: 1. Garbage Identification 2. Adaptive Resource Utilization Garbage Identification is concerned with an analysis of dynamic data dependencies to infer those items that the application is no longer going to access. Several garbage identification algorithms are examined. Each one of the algorithms uses a set of application properties (possibly distinct from one another) to reduce the memory consumption of the application. The performance of these garbage identification algorithms is compared to the performance of an ideal garbage collector, using a novel logging/post-mortem analyzer. The results indicate that the algorithms that achieve a low memory footprint (close to that of an ideal garbage collector) perform their garbage identification decisions locally; however, they base these decisions on best-effort global information obtained from other components of the distributed application. The Adaptive Resource Utilization (ARU) algorithm analyzes the dynamic relationships between the production and consumption of data items. It uses this information to infer the capacity of the system to process data items and adjusts data generation accordingly. The ARU algorithm makes local capacity decisions based on best-effort global information. This algorithm is found to be as effective as the most successful garbage identification algorithm in reducing the memory footprint of stream-based applications, thus confirming the observation that using best-effort global information to perform local decisions is fundamental in reducing memory consumption for stream-based applications.

Continuous live stream analysis applications are increasingly common. Video-based surveillance, emergency response, disaster recovery, and critical infrastructure monitoring are all examples of such applications. These applications are distributed and typically require significant computing resources (like a cluster of workstations) for analysis. In addition to live data, many such applications also require access to historical data that was streamed in the past and is now archived. While distributed programming support for traditional high-performance computing applications is fairly mature, existing solutions for live stream analysis applications are still in their early stages and, in our view, inadequate. We explore the system-level value of recognizing temporal properties -- a critical aspect of the application domain. We present "temporal streams", a programming model supporting a higher-level, domain-targeted programming abstraction for such applications. It provides a simple but expressive stream abstraction encompassing transport, manipulation and storage of streaming data. The semantics of the programming model are tailored to the application domain by explicitly recognizing the temporal aspects of continuous streams, providing a common interface for both time-based retrieval of current streaming data and data persistence. The unifying trait of time enables access to both current streaming data and archived historical data using the same interface; the communication and storage abstraction are the same -- a unified stream data abstraction, uniformly modeling stream data interactions. "Temporal streams" defines how distributed threads of computation interact implicitly via streams, but does not impose a particular model of computation constraining the interactions between distributed actors, targeting loosely coupled distributed systems with no centralized control. In particular, it targets stream analysis scenarios requiring significant signal processing on heavyweight streams such as audio and video. These unstructured streams are data rich but are not directly interpretable until meaningful features are extracted; consequently, feature detection and subsequent analysis are the major computational requirements. We also use the programming model as a vehicle for exploring systems software design issues, realizing "temporal streams" as a distributed runtime in the tradition of loosely coupled distributed systems with strong communication boundaries. We thoroughly examine the concrete software architecture and elements of implementation. We also describe two generations of system implementations, including the broad development philosophy, specific design principles and salient low-level details. The runtime is designed to be relatively lightweight and suitable as a substrate for higher-level, more domain-specific middleware or application functionality. Even with a relatively simple programming model, a carefully designed system architecture can provide a surprisingly rich and flexibly substrate for upper software layers. We also evaluate our system implementation in two ways; first, we present a series of quantitative experimental results designed to assess the performance of key primitives in our architecture in isolation. We also use motivating applications to evaluate "temporal streams" in the context of realistic application scenarios. We develop three motivating applications and provide quantitative and qualitative analyses of these applications in the context of "temporal streams." We show that, although it provides needed higher-level functionality to enable live stream analysis applications, our runtime does not add significant overhead to the stream computation at the core of each application. Finally, we also review the relationship of "temporal streams" (both the programming model and architecture) to other approaches, including database-oriented Stream Data Management Systems (SDMS), various stream processing engines, stream programming languages and parallel batch processing systems, as well as traditional distributed programming systems and communication frameworks.

Syfte: Vi vill ta reda på hur teknikutvecklingen relaterad till VoD påverkar beteendet hos unga vuxna och hur detta beteende förändrar tv-tittandet i denna målgrupp. Teori: Denna studie använder huvudsakligen två teorier för att undersöka problemet. Den första teori som tas upp är Diffusion of innovation, Rogers (2003) som diskuterar innovationers spridning och påverkan i samhället. För att vidare undersöka beteendet hos unga vuxna används Jakob Bjurs avhandling Transforming Audiences (2009) som undersöker individualiseringens mönster inom tv-tittande. Metod: En kvalitativ empirisk fallstudie baserad på intervjuer av fokusgrupper samt personintervju. Detta stöds av en kvantitativ undersökning i syfte att skapa en triangulering för att minimera risken för en felaktig tolkning av resultatet. Resultat: Unga vuxna vill inte längre anpassa sig till tv-tablåer. Generationen blir allt mer individualiserad och vill därför välja helt på egen hand var och när de skall titta på exempelvis ett tv-program. Medieföretagen är medvetna om detta skifte från linjär-tv till VoD och således finns ett fokus på att utveckla ett mer individ-anpassat tittande. Trots individualiseringen och de förbättrade VoD-tjänsterna vill många se bland annat nyheter, större sportevenemang samt melodifestivalen via linjär-tv. Slutsats: Den största anledningen till att många gör denna övergång från linjär-tv till VoD är att de söker en flexibilitet som linjär-tv inte kan erbjuda. Flexibiliteten har gjorts möjlig genom den teknikutveckling som skett inom datorer, smarttelefoner och surfplattor. Det som lockar många VoD-användare till att fortfarande titta på linjär-tv är de sändningar som är viktiga att se i realtid. Tack vare dessa kommer förmodligen tv-tittandet finnas kvar en tid framöver, dock ser vi sjunkande tittarsiffror i de yngre generationerna vilket gör framtiden för linjär-tv oviss.

Thesis (Ph. D.)--Ohio State University, 2005. / Title from first page of PDF file. Document formatted into pages; contains xix, 136 p.; also includes graphics (some col.). Includes bibliographical references (p. 129-136). Available online via OhioLINK's ETD Center

Zugl.: Darmstadt, Techn. University, Diss., 2008.