Network Functions Virtualization (NFV) is a concept, which has attracted significant attention as a promising approach towards the virtualization/“softwarisation” of network infrastructures. With the aim of promoting NFV, this paper outlines an integrated architecture, designed and developed within the context of the EU FP7 T-NOVA project, which allows network operators not only to deploy virtualized Network Functions (NFs) for their own needs, but also to offer them to their customers, as value-added services (Network Functions as-a-Service, NFaaS). Virtual network appliances (gateways, proxies, firewalls, transcoders, analyzers etc.) can be provided on-demand as-a-Service, eliminating the need to acquire, install and maintain specialized hardware at customers' premises. A “NFV Marketplace” is also introduced, where network services and functions created by a variety of developers can be published, acquired and instantiated on-demand
Abstract-This paper presents a novel theoretical framework for end-to-end video quality prediction of MPEG-based video sequences. The proposed framework encloses two discrete models: i) A model for predicting the video quality of an encoded signal at a pre-encoding stage and ii) A model for mapping QoSsensitive network parameters (i.e. packet loss) to video quality degradation. The efficiency of both the discrete models is experimentally validated, proving by this way the accuracy of the proposed framework.
Abstract-This paper presents a novel theoretical framework for end-to-end video quality prediction of MPEG-based video sequences. The proposed framework encloses two discrete models: i) A model for predicting the video quality of an encoded signal at a pre-encoding stage and ii) A model for mapping QoSsensitive network parameters (i.e. packet loss) to video quality degradation. The efficiency of both the discrete models is experimentally validated, proving by this way the accuracy of the proposed framework.
Multimedia applications, and especially encoded video services, are expected to play a major role in the 3rd generation (3G) and beyond mobile communication systems. Given that future service providers are expected to provide video applications at various price and quality levels, quick and economically affordable methods for preparing/encoding the offering media at various qualities are necessary to be developed. This paper presents a method for objective evaluation of the perceived quality of MPEG-4 video content, based on a quantification of subjective assessments. Showing that subjectively derived perceived quality of service (PQoS) vs. bit rate curves can be successfully approximated by a group of exponential functions, the proposed method exploits a simple objective metric, which is obtained from the mean frame rate vs. bit rate curves of an encoded clip. The validity of this metric is assessed by comparing subjectively derived PQoS results to the corresponding ones, which come from the proposed objective method, showing that the proposed technique provides satisfactory PQoS estimation.Index Terms: MPEG-4, objective measurements, perceived quality of service (PQoS).
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