Optimization of Hierarchical System for Data Acquisition

Television broadcasting over IP networks (IPTV) is one of a number of network applications that are except of media distribution also interested in data acquisition from group of information resources of variable size. IP-TV uses Real-time Transport Protocol (RTP) protocol for media streaming and RTP Control Protocol (RTCP) protocol for session quality feedback. Other applications, for example sensor networks, have data acquisition as the main task. Current solutions have mostly problem with scalability - how to collect and process information from large amount of end nodes quickly and effectively? The article deals with optimization of hierarchical system of data acquisition. Problem is mathematically described, delay minima are searched and results are proved by simulations

Jitter buffer loss estimate for effective equipment impairment factor

The paper deals with a proposal of original E-model modification, the new model includes improvements giving more precise results when a jitter is present in transmission channel. Our idea is based on the fact that the network jitter can affect overall delay in delivery or a packet loss due to a limitation of play-out buffer in IP phones or VoIP gateways. Delay is incorporated in an impairment factor Id of E-model whereas losses are issue of Ie-eff parameter. We examined how the estimated speech quality is affected by jitter and compared computed results with MOS values gained by PESQ objective intrusive method (Perceptual Evaluation of Speech Quality). Experiments were performed in circumstances of varying delay, packet loss, jitter and play-out buffer. We have proved that the proposed modification improves estimated MOS computed by Emodel.Scopus7324824

Voting service for IPTV

Tato práce se zabývá návrhem a realizací hlasovací služby pro internetovou televizi. Realizace této služby je provedena v programovacím jazyce Java a využívá již hotových programových struktur, které jsou určené pro simulování vlastností stromového přenosového protokolu. Mimo návrh a realizaci hlasovací služby jsou zde prezentovány protokoly, které pro svou komunikaci využívá internetová televize a jejichž vlastnosti využívá i v této práci realizovaná hlasovací služba. Jelikož realizace přesně nedodržuje návrh hlasovací služby jsou zde uvedeny i rozdíly mezi navrženou a realizovanou hlasovací službou.This thesis deals with a concept and implementation of voting service for IPTV. Implementation of this service is executed in programming language Java and uses programming structures, which were already done. These structures are intended for simulation of propertys of tree transmition protocol. Outside of the concept and implementation of voting service, there are presented protocols, which IPTV uses for communication. And also voting service, implemented in this thesis, uses their propertys. There are also mentioned dierences between outlined and implemented voting service as the implementation does not keep strictly the concept of the voting service.

Arquitecturas IPTV

Dissertação apresentado à Escola Superior de Tecnologia e Gestão do IPL para obtenção do grau de Mestre em Engenharia Informática - Computação Móvel, orientada pelo Professor Doutor Carlos Manuel da Silva Rabadão.Os operadores de telecomunicações de todo o Mundo estão a investir em novas formas de fornecer aos seus clientes serviços de TV + Voz + Internet, em redes IP unificadas, que proporcionam novas oportunidades de negócio, e serviços inovadores, onde o IPTV se encaixa na perfeição. Esta dissertação propõe um estudo na área de IPTV, com especial atenção nas arquitecturas de rede, codecs, protocolos, QoS/QoE, e redes wireless. O serviço de IPTV é extremamente sensível a perdas e atrasos de pacotes nas redes de cabo, mas nas redes wireless existem outras condicionantes que degradam o serviço ainda mais. Baseado neste estudo é testado o comportamento de live stream multicast (Live IPTV), nas redes wireless, que apresentam várias limitações quando operam com IP multicast. Os testes são realizados numa rede laboratorial, que é uma réplica dum segmento existente na rede wireless da freguesia da Memória, concelho de Leiria. São realizados testes com o mesmo vídeo codificado nas qualididades SD, HD e FHD