La prolifération des appareils portables mène à une croissance du trafic mobile qui provoque une surcharge du cœur du réseau cellulaire. Pour faire face à un tel problème, plusieurs travaux conseillent de stocker les contenus (fichiers et vidéos) dans les small cells. Dans cette thèse, nous proposons d'utiliser les véhicules comme des small cells mobiles et de cacher les contenus à bord, motivés par le fait que la plupart d'entre eux pourra facilement être équipée avec de la connectivité et du stockage. L'adoption d'un tel cloud mobile réduit les coûts d'installation et de maintenance et présente des contraintes énergétiques moins strictes que pour les small cells fixes. Dans notre modèle, un utilisateur demande des morceaux d'un contenu aux véhicules voisins et est redirigé vers le réseau cellulaire après une deadline ou lorsque son playout buffer est vide. L'objectif du travail est de suggérer à un opérateur comment répliquer de manière optimale les contenus afin de minimiser le trafic mobile dans le cœur du réseau. Les principales contributions sont : (i) Modélisation. Nous modélisons le scénario ci-dessus en tenant compte de la taille des contenus, de la mobilité et d'un certain nombre d'autres paramètres. (ii) Optimisation. Nous formulons des problèmes d'optimisation pour calculer les politiques d'allocation sous différents modèles et contraintes. (iii) Analyse des performances. Nous développons un simulateur MATLAB pour valider les résultats théoriques. Nous montrons que les politiques de mise en cache proposées dans cette thèse sont capables de réduire de plus que 50% la charge sur le cœur du réseau cellulaire. / The large diffusion of handheld devices is leading to an exponential growth of the mobile traffic demand which is already overloading the core network. To deal with such a problem, several works suggest to store content (files or videos) in small cells or user equipments. In this thesis, we push the idea of caching at the edge a step further, and we propose to use public or private transportation as mobile small cells and caches. In fact, vehicles are widespread in modern cities, and the majority of them could be readily equipped with network connectivity and storage. The adoption of such a mobile cloud, which does not suffer from energy constraints (compared to user equipments), reduces installation and maintenance costs (compared to small cells). In our work, a user can opportunistically download chunks of a requested content from nearby vehicles, and be redirected to the cellular network after a deadline (imposed by the operator) or when her playout buffer empties. The main goal of the work is to suggest to an operator how to optimally replicate content to minimize the load on the core network. The main contributions are: (i) Modelling. We model the above scenario considering heterogeneous content size, generic mobility and a number of other system parameters. (ii) Optimization. We formulate some optimization problems to calculate allocation policies under different models and constraints. (iii) Performance analysis. We build a MATLAB simulator to validate the theoretical findings through real trace-based simulations. We show that, even with low technology penetration, the proposed caching policies are able to offload more than 50 percent of the mobile traffic demand.

While digital displays have continuously increased in resolution, video content produced before these improvements is however stuck at its original resolution, and the use of some form of scaling is needed for a satisfactory viewing experience on high-resolution displays. In recent years, the field of video scaling has taken a leap forward in output quality, due to the adoption of deep learning methods in research. In this paper, we describe a study wherein we train a convolutional neural network for super-resolution, and conduct a large-scale A/B video quality test in order to investigate if SVT video-ondemand viewers prefer video upscaled using a convolutional neural network to video upscaled using the standard bicubic method. Our results show that viewers generally prefer CNNscaled video, but not necessarily for the types of content this technology would primarily be used to scale. We conclude that the technology of deep upscaling shows promise, but also believe that more optimization and flexibility is need for deep scaling to be viable for mainstream use. / Allteftersom bildskärmstekniken förbättras så får mediekonsumenter tillgång till skärmar med allt högre upplösningar; dock är videomaterial som producerats för en viss bildupplösning, fast på denna nivå, och någon form av skalning måste användas för en bra tittarupplevelse på högupplösta skärmar. På senare tid så har videoskalning förändrats, tack vare användandet av djupinlärningsmetoder inom forskningen. I den här rapporten beskriver vi en studie där vi tränade en djup modell för videouppskalning, och sedan utförde ett storskaligt A/B-test, med syftet att undersöka huruvida SVTs onlinetittare föredrar video skalad med djupinlärning över video skalad med konventionella metoder. Våra resultat visar att tittarna föredrog video skalad med djupinlärning, dock inte nödvändigtvis för det material tekniken främst skulle användas med. Vi drar slutsatsen att videoskalning med hjälp av djupinlärning är lovande, men anser också att mer optimering och flexibilitet behövs innan tekniken kan anses mogen för bred adoption.

In this thesis we study users' viewing motions when watching 360° videos in order to provide information that can be used to optimize future view-dependent streaming protocols. More specifically, we develop an application that plays a sequence of 360° videos on an Oculus Rift Head Mounted Display and records the orientation and rotation velocity of the headset during playback. The application is used during an extensive user study in order to collect more than 21 hours of viewing data which is then analysed to expose viewing patterns, useful for optimizing 360° streaming protocols.

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This thesis deals with the implementation of security guard software for OS Linux using an appropriate web camera. The main part of this application is process running in background using V4L application interface to communicate with web cam. Because this program uses dynamically loaded plug-ins for motion detection, it is very simple to change detection algorithm just by modifying configuration file. Application data can be saved as images or video files. Client application was created for online monitoring by user. It communicates with security guard software over network by TCP/IP protocol. Implemented application layer protocol allows simple client authentication and data encryption.

Throughout history, the construction industry has been known to present many risks to its workers’ safety and is still the cause of many accidents. This thesis examines a potential solution to one of the main problems faced by this field.Teleoperation has gained popularity, especially over the last ten years, and its application can be useful to many domains. Amongst them, research done on teleoperation tools for construction sites has been growing considerably as it appears to be a solution for some of the safety problems that it’s facing. Through a literature study and the building and running of an experiment, it aims to investigate parameters that can influence the performance and user experience of participants while remotely controlling a platform. By selecting a few parameters that can play a role in video streaming, the goal is to correlate their influence on the quality of experience of participants as they experience a prototype for a construction site. After conducting the experiment with multiple test participants, the results are analyzed and can lead to conclusions. Finally, future improvements can be made for another iteration of the experiment.

The aim of this master thesis is to investigate the affordances and limitations of using information visualization methods to visualize errors in real-time video streaming data. The study was carried in Red Bee Media company by following several steps including user research, prototyping, and user evaluation. The user research produced design requirements and basic tasks for the prototype. The prototype had to follow the design requirements and use information visualization techniques to visualize the error data. Next, the prototype was evaluated by 5 expert users, all Red Bee Media employees with 1,5 to 3 years experience of working with the existing Red Bee Media system. The results show the prototype obtained a higher SUS score compared to the Red Bee Media monitoring system. Based on a comparison questionnaire, the prototype also had a better visualization for each basic task compared to Red Bee Media monitoring system. The comments from the user evaluation have been categorized into 4 different labels. Those labels listed several usabilities need to be focused on when developing a video monitoring system. / Syftet med denna masteruppsats är att undersöka möjligheterna och begränsningarna av att använda informationsvisualiseringsmetoder för att visualisera fel i realtidsvideoströmningsdata. Studien genomfördes hos företaget Red Bee Media genom att följa flera steg inklusive användarstudier, framtagning av prototyper och användarutvärdering. Användarstudien gav designkrav och grundläggande uppgifter för prototypen. Prototypen måste följa designkraven och använda informationsvisualiseringstekniker för att visualisera feldata. Därefter utvärderades prototypen av 5 expertanvändare, som är medarbetare inom Red Bee Media med 1,5 till 3 års erfarenhet av att arbeta med det befintliga Red Bee Mediasystemet. Resultaten visar att prototypen erhållit ett högre SUS-poäng jämfört med Red Bee Medias nuvarande övervakningssystem. Genom ett jämförelseformulär erhöll även prototypen en bättre visualisering för varje grundläggande uppgift jämfört med Red Bee Medias övervakningssystem. Kommentarer från användarutvärderingen har kategoriserats i 4 olika kategorier. Dessa anger flertalet användningsområden som måste fokuseras på när ett övervakningssystem utvecklas.

Over the last decade, the wide deployment of wireless access technologies (e.g. WiFi, 3G, and LTE) and the remarkable growth in the volume of streaming video content have significantly altered the telecommunications field. These developments introduce new challenges to the research community including the need to develop new solutions (e.g. traffic models and transport protocols) to address changing traffic patterns and the characteristics of wireless links and the need for new evaluation methods that generate higher fidelity results under more realistic scenarios. Unfortunately, for the last two decades, simulation studies have been the main tool for researchers in wireless networks. In spite of the advantages of simulation studies, overall they have had a negative influence on the credibility of published results. In partial response to this simulation crisis, the research community has adopted testing and evaluation using implementation-based experiments. Implementation-based experiments include field experiments, prototypes, emulations, and testbeds. An example of an implementation-based experiment is the MANIAC Challenge, a wireless networking competition that we designed and hosted, which included creation and operation of ad hoc networks using commodity hardware. However, the lack of software tools to facilitate these sorts of experiments has created new challenges. Currently, researchers must practice kernel programming in order to implement networking experiments, and there is an urgent need to lower the barriers of entry to wireless network experimentation. With respect to the growth in video traffic over wireless networks, the main challenge is a mismatch between the design concepts of current internet protocols (e.g. the Transport Control Protocol (TCP)) and the reality of modern wireless networks and streaming video techniques. Internet protocols were designed to be deployed over wired networks and often perform poorly over wireless links; video encoding is highly loss tolerant and delay-constrained and yet, for reasons of expedience is carried using protocols that emphasize reliable delivery at the cost of potentially high delay. This dissertation addresses the lack of software tools to support implementation-based networking experiments and the need to improve the performance of video streaming over wireless access networks. We propose a new software tool that allows researchers to implement experiments without a need to become kernel programmers. The new tool, called the Flexible Internetwork Stack (FINS) Framework, is available under an open source license. With our tool, researchers can implement new network layers, protocols, and algorithms, and redesign the interconnections between the protocols. It offers logging and monitoring capabilities as well as dynamic reconfigurability of the modules' attributes and interconnections during runtime. We present details regarding the architecture, design, and implementation of the FINS Framework and provide an assessment of the framework including both qualitative and quantitative comparison with significant previous tools. We also address the problem of HTTP-based adaptive video streaming (HAVS) over WiFi access networks. We focus on the negative influence of wireless last-hop connections on network utilization and the end-user quality of experience (QoE). We use a cross-layer approach to design three controllers. The first and second controllers adopt a heuristic cross-layer design, while the third controller formulates the HAVS problem as a Markov decision process (MDP). By solving the model using reinforcement learning, we achieved 20% performance improvement (after enough training) with respect to the performance of the best heuristic controller under unstable channel conditions. Our simulation results are backed by a system prototype using the FINS Framework. Although it may seem predictable to achieve more gain in performance and in QoE by using cross-layer design, this dissertation not only presents a new technique that improves performance, but also suggests that it is time to move cross-layer and machine-learning-based approaches from the research field to actual deployment. It is time to move cognitive network techniques from the simulation environment to real world implementations. / Ph. D.

Title: Fashionspace Portal Author: Jindřich Flídr Department: Department of Software and Computer Science Education Supervisor: RNDr. Tomáš Holan, Ph.D. Abstract: The aim of this thesis is to design architecture and implement web application "Fashionspace". This application allows user to create virtual fashion shows based on videos in an interactive environment. The client application is implemented using the Adobe Flash platform and communicates with the CMS Drupal using services. The application is integrated with many technologies, such as online user communication using the XMPP protocol or HD video streaming. The architecture of this application is modular and is built on the principles of MVC. Keywords: web technologies, RIA, Adobe Flex, CMS Drupal, video streaming

Atualmente existe uma grande variedade de serviços de telecomunicações focados na transmissão de voz, vídeo e dados através de redes complexas, embora, em muitos casos, o usuário final não seja atendido com um nível de qualidade aceitável. Neste trabalho, se avalia como o serviço de streaming de vídeo em uma rede com protocolo Internet (IP) pode ser afetado por uma condição adversa da rede, tal como a variação de atraso (jitter). São mostrados os resultados de avaliações objetivas e subjetivas de streaming de vídeo que indicam que a qualidade de vídeo é diretamente afetada por fatores de degradação da rede IP como a variação de atraso de pacotes. Além disso, se verifica que cenas de maior movimento também são mais afetadas pela variação de atraso. Para a realização dos testes, utiliza-se um cenário de emulação de rede isolado, no qual são parametrizadas diferentes condições de rede. Assim, no canal de transmissão são configurados diversos valores de variação de atraso, obtendo-se uma Base de Dados de vídeos com diferentes graus de degradação de qualidade. Estes vídeos são avaliados utilizando métodos subjetivos: Índice por Categorias Absolutas (ACR - Absolute Category Rating) e Índice por Categorias de Degradação (DCR - Degradation Category Rating) e métricas objetivas: Relação Sinal-Ruído de Pico (PSNR - Peak Signal to Noise Ratio), Índice de Similaridade Estrutural (SSIM - Structural Similarity Index) e Medição de Qualidade de Vídeo (VQM - Video Quality Metric). Com a finalidade de mostrar o desempenho das métricas objetivas em relação às subjetivas são empregados os coeficientes de correlação, além do erro de predição e quadrático médio. Adicionalmente, é importante destacar que a partir dos resultados obtidos são estabelecidos intervalos de valores de variação de atraso para os quais a qualidade do vídeo é considerada aceitável ou não para o usuário final. Finalmente, obtém-se uma Base de Dados de vídeos com diferentes graus de degradação da qualidade e que pode ser utilizada em futuras pesquisas. / Nowadays, there is a wide range of telecommunications services focused on the transmission of voice, video and data across complex networks, although, in many cases, the end user is not satisfied with an acceptable quality level. In this work it is assessed how the video streaming service over an IP network can be affected by adverse conditions on the network, such as packet delay variation (jitter). Results from objective and subjective video streaming assessments are shown and indicate that the video quality is directly affected by IP network degradation factors such as packet delay variation. Beyond that, it is also verified that scenes with great movement content are also more sensitive to packet delay variation. For experimental tests, a network emulation totally isolated is considered, for which different network conditions are parameterized. Then, to the transmission channel, different values of packet delay variation are configured and videos are assessed, using subjective metrics: Absolute Category Rating (ACR) and Degradation Category Rating (DCR), and objective metrics: Peak Signal to Noise Ratio (PSNR), Structural Similarity (SSIM) and Video Quality Metric (VQM). In order to show the performance of objective metrics in relation to subjective ones correlation coefficients are employed as well as the prediction error and the mean square error. Finally, it is important to note that, from the results obtained, it can be established a range of delay variation values in which the video quality is acceptable or not at the end user. Additionally, a Video Data Base is obtained with different degrees of quality degradation and which can be used for future researches.