Navegando por Assunto "Multimedia"

Agora exibindo 1 - 2 de 2

Acesso aberto (Open Access)
Controle de qualidade para 3D-vídeo streaming em redes em malha sem fio
(Universidade Federal do Pará, 2013-02-20) QUADROS, Carlos Jean Ferreira de; CERQUEIRA, Eduardo Coelho; http://lattes.cnpq.br/1028151705135221
Wireless Mesh Networks (WMNs) are envisaged to be one of the most important wireless technologies to provide last mile access in future wireless multimedia networks. In this context, 3D-video is envisioned to attract more and more the multimedia market with the perspective for enhanced applications (video surveillance, mission critical control, entertainment, etc.). However, the challenge of dealing with the uctuating bandwidth, scarce resources and time-varying error rate of these networks, illustrates the need for error-resilient 3D-video transmission. In this context, Forward Error Correction (FEC) approaches are required to provide the distribution of video applications for wireless users with Quality of Service (QoS) and Quality of Experience (QoE) assurance. This study proposal puts forward a FEC-based mechanism with Unequal Error Protection (UEP) to enhance 3D-video transmission in WMNs, while increasing user satisfaction and improving the usage of wireless resources. The benefits and impact of the proposed mechanism will be demonstrated by using simulation, the assessment will be conducted with objective and subjective QoE metrics.
Acesso aberto (Open Access)
Um mecanismo para realçar a conectividade de roteamento geográfico na transmissão multimídia em VANTs
(Universidade Federal do Pará, 2014-06-16) COSTA, Rodrigo Medeiros; CERQUEIRA, Eduardo Coelho; http://lattes.cnpq.br/1028151705135221
Networks of Unmanned Aerial Vehicles (UAVs) have enhanced the use of multimedia applications due to their high degree of mobility and versatility. This increase occurs due the accessibility and use of UAVs quadricopters in several civilian applications. Civilian applications have as main characteristic the use of multimedia data such as videos, because they o er a more detailed visual perspective of the environment. The transmission of such data in UAV networks by geographic protocols improves the rate of data delivery. However, it is not su cient to provide quality of experience (QoE). This is because the high degree of mobility of the quadricopters, which leads to link breaks during multimedia transmission. Consequently, it impairs connectivity and induces high packet losses and delays. Therefore, this paper proposes a mechanism called RCRV, based on techniques for predicting mobility in terms of positioning and link estimation time to enhance the decision making process in geographic routing protocols. Furthermore, it employs criteria that consider the behavior of mobility of UAVs. Thus, RCRV enables the extension of connectivity in UAV networks. The RCRV is a mechanism that complements the strategies of geographic routing protocols. In this way, added the RCRV to the GPSR protocol to evaluate the gains and bene ts of him in a geographic routing protocol. Simulations were performed with di erent speeds and numbers of UAVs. The results showed that the RCRV increases the connectivity in the multimedia transmission, improving the delivery of multimedia content and video quality observed by the user.