22 research outputs found
Architectures and Algorithms for Content Delivery in Future Networks
Traditional Content Delivery Networks (CDNs) built with traditional Internet technology are
less and less able to cope with today’s tremendous content growth. Enhancing infrastructures
with storage and computation capabilities may help to remedy the situation. Information-Centric
Networks (ICNs), a proposed future Internet technology, unlike the current Internet, decouple
information from its sources and provide in-network storage. However, content delivery over in-network
storage-enabled networks still faces significant issues, such as the stability and accuracy
of estimated bitrate when using Dynamic Adaptive Streaming (DASH). Still Implementing new
infrastructures with in-network storage can lead to other challenges. For instance, the extensive
deployment of such networks will require a significant upgrade of the installed IP infrastructure.
Furthermore, network slicing enables services and applications with very different characteristics
to co-exist on the same network infrastructure.
Another challenge is that traditional architectures cannot meet future expectations for streaming
in terms of latency and network load when it comes to content, such as 360° videos and immersive
services. In-Network Computing (INC), also known as Computing in the Network (COIN), allows
the computation tasks to be distributed across the network instead of being computed on servers to
guarantee performance. INC is expected to provide lower latency, lower network traffic, and higher
throughput. Implementing infrastructures with in-network computing will help fulfill specific
requirements for streaming 360° video streaming in the future. Therefore, the delivery of 360° video and immersive services can benefit from INC.
This thesis elaborates and addresses the key architectural and algorithmic research challenges
related to content delivery in future networks. To tackle the first challenge, we propose algorithms
for solving the inaccuracy of rate estimation for future CDNs implementation with in-network
storage (a key feature of future networks). An algorithm for implementing in-network storage
in IP settings for CDNs is proposed for the second challenge. Finally, for the third challenge,
we propose an architecture for provisioning INC-enabled slices for 360° video streaming in next-generation
networks. We considered a P4-enabled Software-Defined network (SDN) as the physical
infrastructure and significantly reduced latency and traffic load for video streaming
QoE management of multimedia streaming services in future networks : a tutorial and survey
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Video Caching, Analytics and Delivery at the Wireless Edge: A Survey and Future Directions
Future wireless networks will provide high bandwidth, low-latency, and ultra-reliable Internet connectivity to meet the requirements of different applications, ranging from mobile broadband to the Internet of Things. To this aim, mobile edge caching, computing, and communication (edge-C3) have emerged to bring network resources (i.e., bandwidth, storage, and computing) closer to end users. Edge-C3 allows improving the network resource utilization as well as the quality of experience (QoE) of end users. Recently, several video-oriented mobile applications (e.g., live content sharing, gaming, and augmented reality) have leveraged edge-C3 in diverse scenarios involving video streaming in both the downlink and the uplink. Hence, a large number of recent works have studied the implications of video analysis and streaming through edge-C3. This article presents an in-depth survey on video edge-C3 challenges and state-of-the-art solutions in next-generation wireless and mobile networks. Specifically, it includes: a tutorial on video streaming in mobile networks (e.g., video encoding and adaptive bitrate streaming); an overview of mobile network architectures, enabling technologies, and applications for video edge-C3; video edge computing and analytics in uplink scenarios (e.g., architectures, analytics, and applications); and video edge caching, computing and communication methods in downlink scenarios (e.g., collaborative, popularity-based, and context-aware). A new taxonomy for video edge-C3 is proposed and the major contributions of recent studies are first highlighted and then systematically compared. Finally, several open problems and key challenges for future research are outlined
Cross-shore sediment transport processes on natural beaches and their relation to sand bar migration patterns
During the last two decadess everalf ield studiesh ave shown a clear pattern in the cross-shores ediment
transport processes on beaches. Outside the surf zone, the stronger onshore velocities under unbroken (Stokes-type)
wave crests, produce a dominant onshore sediment transport. Inside the surf zone, strong offshore-directed mean
currents (undertow) drive sediments offshore. It is of great interest for the scientific community to verify further the
consistency of this pattern under different morphodynamic conditions, understand the underlying physics and
quantify/parameterise this behaviour in order to improve the understanding of cross-shore sediment transport and
simplify the modelling of beach profile change.
The present investigation addresses this niche by i) analysing cross-shore sediment transport processes with
field data spanning the swash, surf and shoaling zones, ii) quantifying (parameterising) the cross-shore structure of
such processes, and iii) incorporating the sediment transport parameterisation (shape function) into a model of bar
generation and migration. To achieve this, concurrent measurements of velocity, surface elevation and suspended
sediment concentration (SSC) were obtained with electromagnetic current meters (EMCM), pressure transducers
(PT), and optical backscatter sensors (OBS) on five different beaches across Europe under a wide range of
morphodynamic conditions. Results show that the normalised (by the local energy level) net cross-shore sediment
transport, expressed as moments of the velocity field (energetics approach), has a remarkably coherent structure
across-shore (shape function, SF) in all the data sets. The pattern consists of net onshore transport in the swash zone,
offshore transport inside the surf zone, and onshore transport outside the surf zone with a convergence of sediment
around the breaking point and a divergence in the inner surf/swash zone. This behaviour is a product of the balance
between multiple opposing mechanisms, and a few of them describe the overall pattern, namely short wave
skewness outside the surf zone (onshore transport), and the combined effect of undertow and wave stirring at short
and long frequencies inside the surf zone (offshore transport). The velocity moments SF represents the cross-shore
distribution of the cross-shore sediment transport processes and it is observed to compare well (linear correlation of
0.61) with the cross-shore structure of the measured sediment fluxes.
The shapef unction was incorporatedin to a time dependenmt odel of beachp rofile changew ith the aim of
reproducing bar migration patterns as observed in the field (Gallagher et al., 1998). The SF-based profile model
comprises a simple wave transformation routine that accounts for linear shoaling and assumes a saturation law for
wave decay inside the surf zone. An energetics approach (Bailard, 1981) is then used to calculate sediment fluxes
with the third and fourth velocity moments parameterised via shape functions. Profile change is calculated by
solving numerically the mass conservation equation. When the SF model is forced with measured offshore wave
conditions and an initial beach profile, the model can successfully predict bar generation and migration (R2 = 0.86)
over 77 days as observed at Duck, North Carolina, a microtidal beach unrelated to the development of the SF. This
includes events of bar migration offshore, onshore or no net movement (stable bar). These results show that the
convergence of sediment at the breakpoint (breakpoint hypothesis) combined with the morphological feedback can
successfully explain the generation and evolution of shore parallel bars over months. The model cannot replicate the
whole profile shape, but it is able to produce realistic bar behaviour such as net offshore movement of sandbars,
generation close to the shore, volume growth as they travel offshore, bar amplitude decay when continuously
subjected to an unbroken wave regime, onshore bar migration, and the subdued morphology of macrotidal beaches.the Mexican Council for Science and Technology (CONACYT) and the Overseas Research Grant programme of the CVCP, U
Tile-based panoramic live video streaming on ICN
Information-centric networking (ICN) is a future Internet architecture that makes it possible to effectively use various in-network functions, such as cache storage, computing resources and multi-path. However, applications need to be carefully designed in order to fully gain the benefits of these functions. This paper presents a 360-degree panoramic live video streaming application as an example of an application design suitable for in-network functions, especially cache storage. The key ideas are content sharing by video frame tiling and load balancing by transcoding. The implementation based on the application design shows the benefits and the problems of these features. Additionally, this paper discusses problems that remain to be resolved
Library buildings around the world
"Library Buildings around the World" is a survey based on researches of several years. The objective was to gather library buildings on an international level starting with 1990
2017, UMaine News Press Releases
This is a catalog of press releases put out by the University of Maine Division of Marketing and Communications between January 3, 2017 and December 29, 2017
Report on active and planned spacecraft and experiments
Information is presented, concerning active and planned spacecraft and experiments known to the National Space Science Data Center. The information included a wide range of disciplines: astronomy, earth sciences, meteorology, planetary sciences, aeronomy, particles and fields, solar physics, life sciences, and material sciences. These spacecraft projects represented the efforts and funding of individual countries as well as cooperative arrangements among different countries
Apollo scientific experiments data handbook
A brief description of each of the Apollo scientific experiments was described, together with its operational history, the data content and formats, and the availability of the data. The lunar surface experiments described are the passive seismic, active seismic, lunar surface magnetometer, solar wind spectrometer, suprathermal ion detector, heat flow, charged particle, cold cathode gage, lunar geology, laser ranging retroreflector, cosmic ray detector, lunar portable magnetometer, traverse gravimeter, soil mechanics, far UV camera (lunar surface), lunar ejecta and meteorites, surface electrical properties, lunar atmospheric composition, lunar surface gravimeter, lunar seismic profiling, neutron flux, and dust detector. The orbital experiments described are the gamma-ray spectrometer, X-ray fluorescence, alpha-particle spectrometer, S-band transponder, mass spectrometer, far UV spectrometer, bistatic radar, IR scanning radiometer, particle shadows, magnetometer, lunar sounder, and laser altimeter. A brief listing of the mapping products available and information on the sample program were also included