Efficient and Effective Schemes for Streaming Media Delivery

The rapid expansion of the Internet and the increasingly wide deployment of wireless networks provide opportunities to deliver streaming media content to users at anywhere, anytime. To ensure good user experience, it is important to battle adversary effects, such as delay, loss and jitter. In this thesis, we first study efficient loss recovery schemes, which require pure XOR operations. In particular, we propose a novel scheme capable of recovering up to 3 packet losses, and it has the lowest complexity among all known schemes. We also propose an efficient algorithm for array codes decoding, which achieves significant throughput gain and energy savings over conventional codes. We believe these schemes are applicable to streaming applications, especially in wireless environments. We then study quality adaptation schemes for client buffer management. Our control-theoretic approach results in an efficient online rate control algorithm with analytically tractable performance. Extensive experimental results show that three goals are achieved: fast startup, continuous playback in the face of severe congestion, and maximal quality and smoothness over the entire streaming session. The scheme is later extended to streaming with limited quality levels, which is then directly applicable to existing systems

Geniş ölçekli ağlar için yeni bir dağıtık ayrık olay tabanlı benzetim yaklaşımı ve uygulaması

06.03.2018 tarihli ve 30352 sayılı Resmi Gazetede yayımlanan “Yükseköğretim Kanunu İle Bazı Kanun Ve Kanun Hükmünde Kararnamelerde Değişiklik Yapılması Hakkında Kanun” ile 18.06.2018 tarihli “Lisansüstü Tezlerin Elektronik Ortamda Toplanması, Düzenlenmesi ve Erişime Açılmasına İlişkin Yönerge” gereğince tam metin erişime açılmıştır.Modelleme ve benzetim teorisi ağ tasarım ve protokollerini test etme ve dinamik ağ davranışını anlama da önemli bir araçtır. En büyük ağ olan İnternetin baş döndürücü bir hızla büyümesi, yeni benzetim tekniklerini geliştirmeyi zorunlu kılmaktadır. Yapılan çalışmada geniş ölçekli ağlar için ayrık olay tabanlı yeni bir paralel ve dağıtık benzetim yaklaşımı ve ağ benzetim aracı geliştirilmiştir. DEVS modelleme yaklaşımı kullanılarak istemci / sunucu tabanlı, ölçeklenebilir, platformdan bağımsız, esnek ‘D-DEVSNET’ isimli yeni bir ağ benzetim aracının modelleme ve tasarımı gerçekleştirilmiş ve başarım analizleri yapılmıştır. D-DEVSNET ağ benzetim aracının başarımını ve DEVS yaklaşımının paralel ve dağıtık uygulamalardaki gücünü göstermek amacıyla belirli bir zaman periyotunda farklı ölçeklerdeki ağlarda iş çıkarma yeteneği, uçtan uca ortalama paket gecikmesi ve kayıp paket miktarı gibi testler yapılmıştır. Yapılan testler sonucunda DDEVSNET benzetim aracının iyi bir ölçeklenebilirliğe ve yüksek bir performansa sahip olduğu, benzetim aracı performansının, ağdaki düğüm / yönlendirici sayısından (artmasından veya azalmasından) ve donanım kapasitesinden fazla etkilenmediği görülmüştür. Geliştirilen benzetim aracının, açık kaynak kodlu, paralel ve dağıtık mimaride, web tabanlı çalışabilme yeteneği, benzetim sonuçlarının her aşamada kolay izlenebilirliği, görselliği, kolay kurulumu gibi özellikleri ile uzaktan eğitim çalışmaları başta olmak üzere eğitim amaçlı kullanımı hedeflenmiştir. Bu kapsamda geliştirilen DDEVSNET ağ benzetim aracı, dağıtık, ölçeklenebilir, adaptif ve güçlü ağ uygulamalarının modellenmesi ve tasarımı için örnek bir çerçeve oluşturmuş, DEVS yaklaşımının geniş bir uygulama alanına sahip olduğu gösterilmiştir.Modeling and simulation theory is an important tool for testing network design and protocols as well as understanding the dynamic behavior of the network. Growth of the biggest network, Internet’s dazzling speed requires new simulation techniques. In this study, a tool was developed for design and implementation of a new discrete event based distributed simulation for large-scale networks. By using DEVS as a modeling approach, client / server based, scalable, platform-independent, flexible new network modeling and simulation tool called ‘D-DEVSNET’ was designed and performance analyzes were conducted. In order to show the performance of the network simulation tool, D-DEVSNET and the power of the DEVS approach on parallel and distributed applications, some tests were carried out such as the measurement of throughput capability of different sized networks in a certain period of time, the average end-to-end packet delay and the amount of packet loss. According to the tests that were conducted, D-DEVSNET has been proven a well-scalable and high performing simulation tool. In addition, it was seen that the performance of the simulation tool was not much affected by the network node / router number (increase or decrease of) and the hardware capacity. Due to its being open sourced, parallel and distributed architecture, easy-to-follow simulation results at every step, visual quality also ability to work in a web based environment and easy installation, the developed simulation tool, D-DEVSNET was mainly aimed to use for distance education studies. The D-DEVSNET network simulation tool developed in this context has created a sample framework for distributed, scalable, adaptive and robust modeling and design of network applications. In the meantime, DEVS approach has been shown to have a wide range of application

Pretend that it is real!: Convergence Culture in Practice

Media convergence has mainly been defined and explained as a technological and industrial phenomenon; as the process where new technologies are accommodated by existing media and communication industries and their cultures of production. One consequence of convergence in today’s hybrid media landscape is that the previously distinct borders between production and consumption have become blurred. This means that convergence also takes place as a bottom-up social process initiated by media users that move almost anywhere and everywhere in search of entertainment experiences of their liking. This thesis sheds light on the different types of media convergence that took place in the process of making the transmedia storytelling production Sanningen om Marika. The Swedish public service provider, SVT, and the pervasive games upstart company, The company P, combined their expertise in broadcasting and games development to craft this ‘participation drama’. During five months in 2007, the production offered Swedes nationwide rich possibilities to interact and participate, or just to watch or lurk on the production’s various platforms. Using an ethnographic approach, field studies were conducted throughout the design, implementation and production phases. The analysis shows that even if instances of convergence could be identified, the collaboration did not proceed smoothly. The companies’ different media logics with their differing cultures of production created tensions and frictions. The different logics of television, internet and games - different in quality demands and with different audience participation models - made it difficult to create a hybrid production. Television genres blurred fiction and facts, and the ordinary was blurred with activities of games and play in the production, making the audience reception and interpretations differ extensively. Lastly, the designed audience participation did not remove the asymmetrical relationship between producers and users in media, but instead highlighted issues of hierarchies, lack of participant empowerment and inequality between participants

Enhancing pharmaceutical innovation through the use of knowledge management

Pharmaceuticailn novation is a complex task that is reliant upon the availability of relevant information and knowledge. To date, the aspects of how, when and where this information and knowledge is applied throughout the drug development processes, has been lightly researched. Furthermore, the science of Knowledge Management can potentially aid the drug development processes and allow an organisation to reduce the time and costs associated with innovative drug development. This thesis examines these issues in greater depth through a series of case studies conducted within the innovative pharmaceutical organisation AstraZeneca. The end result of this research is a Knowledge Management tool set which is capable of driving pharmaceutical innovation. The thesis firstly explores the literature associated with innovation, pharmaceutical innovation, Knowledge Management and Intellectual Capital. The second aspect of the research used the literature review to develop a novel research framework with which to examine pharmaceutical innovation in greater detail. The third stage of the research utilised the results of the previous stages to develop a novel Innovation and Knowledge Management focused model. The fourth stage of this research utilised the research findings to develop a Knowledge Management tool set that can be used to drive innovation. This tool set is comprised of three distinct levels of functionality, namely: the social and collaborative level, the information assimilation and dissemination level and a level that encourages the capture of knowledge. The final stage of the research concludes with a discussion on evaluating Knowledge Management and its use in driving pharmaceutical innovation.EThOS - Electronic Theses Online ServiceGBUnited Kingdo