126 research outputs found
Scalable Peer-to-Peer Streaming for Live Entertainment Content
We present a system for streaming live entertainment content over the Internet originating from a single source to a scalable number of consumers without resorting to centralized or provider-provisioned resources. The system creates a peer-to-peer overlay network, which attempts to optimize use of existing capacity to ensure quality of service, delivering low startup delay and lag in playout of the live content. There are three main aspects of our solution: first, a swarming mechanism that constructs an overlay topology for minimizing propagation delays from the source to end consumers; second, a distributed overlay anycast system that uses a location-based search algorithm for peers to quickly find the closest peers in a given stream; and finally, a novel incentive mechanism that encourages peers to donate capacity even when the user is not actively consuming content
VirtuWind: Virtual and programmable industrial network prototype deployed in operational wind park.
With anticipated exponential growth of connected devices, future industrial networks require an open solutions architecture facilitated by standards and a strong ecosystem. Such solutions should also deal with range of quality of service requirements imposed by industrial networks. Preserving strict quality of service is particularly challenging when services pass across domains of multiple provides. VirtuWind aims to develop and demonstrate a Software Defined Networking and Network Function Virtualization ecosystem, based on an open, modular and secure framework to address stringent requirements of the industrial networks. A prototype of the framework for intra-domain and inter-domain scenarios will be showcased in real Wind Parks, as a representative use case of industrial networks. This paper details this vision and explains steps forward
Algorithm and performance of a clinical IMRT beam-angle optimization system
This paper describes the algorithm and examines the performance of an IMRT
beam-angle optimization (BAO) system. In this algorithm successive sets of beam
angles are selected from a set of predefined directions using a fast simulated
annealing (FSA) algorithm. An IMRT beam-profile optimization is performed on
each generated set of beams. The IMRT optimization is accelerated by using a
fast dose calculation method that utilizes a precomputed dose kernel. A compact
kernel is constructed for each of the predefined beams prior to starting the
FSA algorithm. The IMRT optimizations during the BAO are then performed using
these kernels in a fast dose calculation engine. This technique allows the IMRT
optimization to be performed more than two orders of magnitude faster than a
similar optimization that uses a convolution dose calculation engine.Comment: Final version that appeared in Phys. Med. Biol. 48 (2003) 3191-3212.
Original EPS figures have been converted to PNG files due to size limi
World-leading science with SPIRou - the nIR spectropolarimeter / high-precision velocimeter for CFHT
SPIRou is a near-infrared (nIR) spectropolarimeter / velocimeter proposed as
a new-generation instrument for CFHT. SPIRou aims in particular at becoming
world-leader on two forefront science topics, (i) the quest for habitable
Earth-like planets around very- low-mass stars, and (ii) the study of low-mass
star and planet formation in the presence of magnetic fields. In addition to
these two main goals, SPIRou will be able to tackle many key programs, from
weather patterns on brown dwarf to solar-system planet atmospheres, to dynamo
processes in fully-convective bodies and planet habitability. The science
programs that SPIRou proposes to tackle are forefront (identified as first
priorities by most research agencies worldwide), ambitious (competitive and
complementary with science programs carried out on much larger facilities, such
as ALMA and JWST) and timely (ideally phased with complementary space missions
like TESS and CHEOPS).
SPIRou is designed to carry out its science mission with maximum efficiency
and optimum precision. More specifically, SPIRou will be able to cover a very
wide single-shot nIR spectral domain (0.98-2.35 \mu m) at a resolving power of
73.5K, providing unpolarized and polarized spectra of low-mass stars with a
~15% average throughput and a radial velocity (RV) precision of 1 m/s.Comment: 12 pages, 5 figures, conference proceedings of the French Society of
Astronomy and Astrophysics meeting 201
Curling: Content-ubiquitous resolution and delivery infrastructure for next-generation services
CURLING, a Content-Ubiquitous Resolution and Delivery Infrastructure for Next Generation Services, aims to enable a future content-centric Internet that will overcome the current intrinsic constraints by efficiently diffusing media content of massive scale. It entails a holistic approach, supporting content manipulation capabilities that encompass the entire content life cycle, from content publication to content resolution and, finally, to content delivery. CURLING provides to both content providers and customers high flexibility in expressing their location preferences when publishing and requesting content, respectively, thanks to the proposed scoping and filtering functions. Content manipulation operations can be driven by a variety of factors, including business relationships between ISPs, local ISP policies, and specific content provider and customer preferences. Content resolution is also natively coupled with optimized content routing techniques that enable efficient unicast and multicast-based content delivery across the global Internet
VirtuWind: Virtual and Programmable Industrial Network Prototype Deployed in Operational Wind Park
With anticipated exponential growth of connected
devices, future industrial networks require an open solutions architecture facilitated by standards and a strong ecosystem.VirtuWind aims to develop and demonstrate an SDN and NFV ecosystem, based on an open, modular and secure framework.A prototype of the framework for intra-domain and inter-domain scenarios will be showcased in real wind parks,as a representative use case of industrial networks. Validate the economic viability of the demonstrated solution is paramount for VirtuWind.
This paper details this vision and explains steps forward
SARDANA: an all-optical access-metro WDM/TDM-PON
A new optical access network, named “Scalable Advanced Ring-based passive Dense Access Network
Architecture” (SARDANA), is presented. It transparently integrates WDM metro and TDM PON access
technologies, implementing ring protection, 100 km reach and up to 1024 users served at 10 Gb/s, with
passive highly-shared infrastructure. The introduced innovations are hybrid ring/tree WDM/TDM Passive
Optical Network (PON) architecture; a resilient remote node (RN), which is distantly pumped from the
Optical Line Terminal (OLT); and a reflective ONU (Optical Network Unit); as well as an enhanced
Medium Access Control (MAC) protocol.Postprint (published version
Stable accretion and episodic outflows in the young transition disk system GM Aurigae
We investigate the structure and dynamics of the magnetospheric accretion
region and associated outflows on a scale smaller than 0.1 au around the young
transitional disk system GM Aur. We monitored the variability of the system on
timescales ranging from days to months, using high-resolution optical and
near-infrared spectroscopy, multiwavelength photometry, and low-resolution
near-infrared spectroscopy, over a total duration of six months (30 rotational
cycles). We analyzed the photometric and line profile variability to
characterize the accretion and ejection processes. The luminosity of the system
is modulated by surface spots at the stellar rotation period of 6.04 days. The
Balmer, Paschen, and Brackett hydrogen lines as well as the HeI 5876 A and HeI
10830 A line profiles are modulated on the same period. The PaB line flux
correlates with the photometric excess in the u' band, which suggests that most
of the line emission originates from the accretion process. High-velocity
redshifted absorptions reaching below the continuum periodically appear in the
near-infrared line profiles at the rotational phase in which the veiling and
line fluxes are the largest. These are signatures of a stable accretion funnel
flow and associated accretion shock at the stellar surface. This large-scale
magnetospheric accretion structure appears fairly stable over at least 15 and
possibly up to 30 rotational periods. In contrast, outflow signatures randomly
appear as blueshifted absorption components in the Balmer and HeI 10830 A line
profiles and disappear on a timescale of a few days. The coexistence of a
stable, large-scale accretion pattern and episodic outflows supports
magnetospheric ejections as the main process occurring at the star-disk
interface. Stable magnetospheric accretion and episodic outflows appear to be
physically linked on a scale of a few stellar radii in this system.Comment: 30 pages, 28 figures, 12 tables, accepted for publication in
Astronomy & Astrophysic
Effects of Eprosartan on Serum Metabolic Parameters in Patients with Essential Hypertension
The effect of the anti-hypertensive drug eprosartan on metabolic parameters is currently not extensively documented. We evaluated the effect of eprosartan on parameters involved in atherogenesis, oxidative stress and clotting activity. This open-label unblinded intervention study included 40 adult patients with essential hypertension taking eprosartan. Eprosartan significantly reduced by 8% (p<0.001) the systolic and by 13% (p<.001) the diastolic blood pressure, and in-creased by 24% the time needed to produce oxidative by-products (p=0.001), a marker of oxidative stress. In contrast, ep-rosartan did not alter 8-isoprostane (8-epiPGF2a) levels, another marker of oxidative stress. Additionally, eprosartan re-duced by 14% aspartate aminotransferase and by 21% then alanine aminotransferase activity, while it had a neutral effect on the lipid profile and apolipoprotein levels and did not influence glucose homeostasis, creatinine and uric acid levels. Eprosartan did not affect the clotting/fibrinolytic status (estimated by plasminogen activator inhibitor 1, tissue plasmino-gen activator and a2 antiplasmin levels), or the enzymatic activity of the lipoprotein associated phospholipase A2 (Lp-PLA2) and paraoxonase 1 (PON1). In conclusion, eprosartan should be mainly considered as an anti-hypertensive agent with neutral effects on most of the metabolic parameters in hypertensive patients
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