30 research outputs found
Service specific management and orchestration for a content delivery network
Any non-trivial network service requires service specific orchestration to meet its carrier-grade requirements regarding resiliency, availability, etc. How the network service components are mapped on the substrate, how VNFs get reconfigured after a monitored event or how they scale, only network service/function developers know how to execute such workflows to guarantee an optimal QoS. It is therefore of paramount importance that NFV Service Platforms allow developer specified input when performing such life cycle events, instead of defining generic workflows. Within the scope of the SONATA and SGTANGO projects, a mechanism was designed that allows developers to create and execute Service and Function Specific Managers. These managers are processes, created by the developer, that define service or function specific orchestration behaviour. The SONATA Service Platform executes these managers to overwrite generic Service Platform behaviour, creating developer customised life cycle workflows. We will demonstrate the development, testing and operational execution of these managers by using a Content Delivery Network which requires specific placement and scaling behaviour
Multiwavelength Observations of the Low Metallicity Blue Compact Dwarf Galaxy SBS 0335-052
New infrared and millimeter observations from Keck, Palomar, ISO, and OVRO
and archival data from the NRAO VLA and IRAS are presented for the low
metallicity blue compact dwarf galaxy SBS 0335-052. Mid-infrared imaging shows
this young star-forming system is compact (0.31"; 80 pc) at 12.5 microns. The
large Br-gamma equivalent width (235 Angstroms) measured from integral field
spectroscopy is indicative of a ~5 Myr starburst. The central source appears to
be optically thin in emission, containing both a warm (~80 K) and a hot (~210
K) dust component, and the overall interstellar radiation field is quite
intense, about 10,000 times the intensity in the solar neighborhood. CO
emission is not detected, though the galaxy shows an extremely high global H I
gas-to-dust mass ratio, high even for blue compact dwarfs. Finally, the
galaxy's mid-infrared-to-optical and mid-to-near-infrared luminosity ratios are
quite high, whereas its far-infrared-to-radio and far-infrared-to-optical flux
ratios are surprisingly similar to what is seen in normal star-forming
galaxies. The relatively high bolometric infrared-to-radio ratio is more easily
understood in the context of such a young system with negligible nonthermal
radio continuum emission. These new lines of evidence may outline features
common to primordial galaxies found at high redshift.Comment: 28 pages including 6 figures; accepted for publication in the
Astronomical Journa
An adaptive system for real-time scalable video streaming with end- to-end qos control
This paper presents a real-time adaptive video streaming system based on the latest standardized video codec H.264/MPEG-4 AVC scalable extension (SVC). The system provides a full MPEG-21 media access framework over heterogeneous networks and terminals with end-to-end QoS control and multimedia adaptation based on SVC. This adaptive streaming system is composed of a server with a real-time SVC encoder, an adaptive network node, and a terminal with appropriate feedback of perceptual quality, network conditions and user preferences for adaptation support. The system facilitates a general content adaptation solution to achieve the end-to-end QoS control
Demo: closed-loop security orchestration in the telco cloud for moving target defense
This work presents a Moving Target Defense (MTD) framework for the protection of network slices and virtual resources in a telco cloud environment. The preliminary implementation provides closed-loop security management of services with proactive MTD operations to reduce the success probability of attacks, and reactive MTD operations, empowered by a tampering detection and a traffic-based anomaly detection system. MTD strategies are adaptive and optimized with deep reinforcement learning (deep-RL) for balancing costs, security, and availability goals defined in a Multi-Objective Markov Decision Process (MOMDP)
A cloud-enabled small cell architecture in 5G networks for broadcast/multicast services
© 2019 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.The evolution of 5G suggests that communication networks become sufficiently flexible to handle a wide variety of network services from various domains. The virtualization of small cells as envisaged by 5G, allows enhanced mobile edge computing capabilities, thus enabling network service deployment and management near the end user. This paper presents a cloud-enabled small cell architecture for 5G networks developed within the 5G-ESSENCE project. This paper also presents the conformity of the proposed architecture to the evolving 5G radio resource management architecture. Furthermore, it examines the inclusion of an edge enabler to support a variety of virtual network functions in 5G networks. Next, the improvement of specific key performance indicators in a public safety use case is evaluated. Finally, the performance of a 5G enabled evolved multimedia broadcast multicast services service is evaluated.Peer ReviewedPostprint (author's final draft
The Sigma - D relation for planetary nebulae
We present an extended analysis of the relation between radio surface
brightness and diameter -- the so-called relation for planetary
nebulae (PNe). We revise our previous derivation of the theoretical
relation for the evolution of bremsstrahlung surface brightness in order to
include the influence of the fast wind from the central star. Different
theoretical forms are derived: for the first and second
phases of evolution and for the final stage of
evolution. Also, we analyzed several different Galactic PN samples. All samples
are influenced by severe selection effects, but Malmquist bias seems to be less
influential here than in the supernova remnant (SNR) samples. We derived
empirical relations for 27 sample sets using 6 updated PN papers
from which an additional 21 new sets were extracted. Twenty four of these have
a trivial form of . However, we obtain one empirical
relation that may be useful for determining distances to PNe. This
relation is obtained by extracting a recent nearby (< 1 kpc) Galactic PN
sample.Comment: 12 pages, 3 tables, 4 figures. Accepted for publication in Astronomy
& Astrophysic
Technology pillars in the architecture of future 5G mobile networks: NFV, MEC and SDN
This paper analyzes current standardization situation of 5G and the role network softwarization plays in order to address the challenges the new generation of mobile networks must face. This paper surveys recent documentation from the main stakeholders to pick out the use cases, scenarios and emerging vertical sectors that will be enabled by 5G technologies, and to identify future high-level service requirements. Driven by those service requirements 5G systems will support diverse radio access technology scenarios, meet end-to-end user experienced requirements and provide capability of flexible network deployment and efficient operations. Then, based on the identified requirements, the paper overviews the main 5G technology trends and design principles to address them. In particular, the paper emphasizes the role played by three main technologies, namely SDN, NFV and MEC, and analyzes the main open issues of these technologies in relation to 5G.Preprin