193 research outputs found
On the feasibility of collaborative green data center ecosystems
Get PDFThe increasing awareness of the impact of the IT sector on the environment, together with economic factors, have fueled many research efforts to reduce the energy expenditure of data centers. Recent work proposes to achieve additional energy savings by exploiting, in concert with customers, service workloads and to reduce data centers’ carbon footprints by adopting demand-response mechanisms between data centers and their energy providers. In this paper, we debate about the incentives that customers and data centers can have to adopt such measures and propose a new service type and pricing scheme that is economically attractive and technically realizable. Simulation results based on real measurements confirm that our scheme can achieve additional energy savings while preserving service performance and the interests of data centers and customers.Peer ReviewedPostprint (author's final draft
An energy-efficient distributed dynamic bandwidth allocation algorithm for Passive Optical Access Networks
Get PDFThe rapid deployment of passive optical access networks (PONs) increases the global energy consumption of networking infrastructure. This paper focuses on the minimization of energy consumption in Ethernet PONs (EPONs). We present an energy-efficient, distributed dynamic bandwidth allocation (DBA) algorithm able to power off the transmitter and receiver of an optical network unit (ONU) when there is no upstream or downstream traffic. Our main contribution is combining the advantages of a distributed DBA (namely, a smaller packet delay compared to centralized DBAs, due to less time being needed to allocate the transmission slot) with energy saving features (that come at a price of longer delays due to the longer queue waiting times when transmitters are switched off). The proposed algorithm analyzes the queue size of the ONUs in order to switch them to doze/sleep mode when there is no upstream/downstream traffic in the network, respectively. Our results show that we minimized the ONU energy consumption across a wide range of network loads while keeping delay bounded.Postprint (published version
Toward hyper-realistic and interactive social VR experiences in live TV scenarios
Get PDF© 2022 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Social Virtual Reality (VR) allows multiple distributed users getting together in shared virtual environments to socially interact and/or collaborate. This article explores the applicability and potential of Social VR in the broadcast sector, focusing on a live TV show use case. For such a purpose, a novel and lightweight Social VR platform is introduced. The platform provides three key outstanding features compared to state-of-the-art solutions. First, it allows a real-time integration of remote users in shared virtual environments, using realistic volumetric representations and affordable capturing systems, thus not relying on the use of synthetic avatars. Second, it supports a seamless and rich integration of heterogeneous media formats, including 3D scenarios, dynamic volumetric representation of users and (live/stored) stereoscopic 2D and 180º/360º videos. Third, it enables low-latency interaction between the volumetric users and a video-based presenter (Chroma keying), and a dynamic control of the media playout to adapt to the session’s evolution. The production process of an immersive TV show to be able to evaluate the experience is also described. On the one hand, the results from objective tests show the satisfactory performance of the platform. On the other hand, the promising results from user tests support the potential impact of the presented platform, opening up new opportunities in the broadcast sector, among others.This work has been partially funded by the European Union’s Horizon 2020 program, under agreement nº 762111 (VRTogether project), and partially by ACCIÓ, under agreement COMRDI18-1-0008 (ViVIM project). Work by Mario Montagud has been additionally funded by the Spanish Ministry of Science, Innovation and Universities with a Juan de la Cierva – Incorporación grant (reference IJCI-2017-34611). The authors would also like to thank the EU H2020 VRTogether project consortium for their relevant and valuable contributions.Peer ReviewedPostprint (author's final draft
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