3,862 research outputs found
APENet: LQCD clusters a la APE
Developed by the APE group, APENet is a new high speed, low latency,
3-dimensional interconnect architecture optimized for PC clusters running
LQCD-like numerical applications. The hardware implementation is based on a
single PCI-X 133MHz network interface card hosting six indipendent
bi-directional channels with a peak bandwidth of 676 MB/s each direction. We
discuss preliminary benchmark results showing exciting performances similar or
better than those found in high-end commercial network systems.Comment: Lattice2004(machines), 3 pages, 4 figure
An agent-based approach to assess drivers’ interaction with pre-trip information systems.
This article reports on the practical use of a multi-agent microsimulation framework to address the issue of assessing drivers’
responses to pretrip information systems. The population of drivers is represented as a community of autonomous agents,
and travel demand results from the decision-making deliberation performed by each individual of the population as regards
route and departure time. A simple simulation scenario was devised, where pretrip information was made available to users
on an individual basis so that its effects at the aggregate level could be observed. The simulation results show that the
overall performance of the system is very likely affected by exogenous information, and these results are ascribed to demand
formation and network topology. The expressiveness offered by cognitive approaches based on predicate logics, such as the
one used in this research, appears to be a promising approximation to fostering more complex behavior modelling, allowing
us to represent many of the mental aspects involved in the deliberation process
High-speed data transfer with FPGAs and QSFP+ modules
We present test results and characterization of a data transmission system
based on a last generation FPGA and a commercial QSFP+ (Quad Small Form
Pluggable +) module. QSFP+ standard defines a hot-pluggable transceiver
available in copper or optical cable assemblies for an aggregated bandwidth of
up to 40 Gbps. We implemented a complete testbench based on a commercial
development card mounting an Altera Stratix IV FPGA with 24 serial transceivers
at 8.5 Gbps, together with a custom mezzanine hosting three QSFP+ modules. We
present test results and signal integrity measurements up to an aggregated
bandwidth of 12 Gbps.Comment: 5 pages, 3 figures, Published on JINST Journal of Instrumentation
proceedings of Topical Workshop on Electronics for Particle Physics 2010,
20-24 September 2010, Aachen, Germany(R Ammendola et al 2010 JINST 5 C12019
Correção do solo para cultivo do cajueiro no cerrado piauiense.
Caracteristicas dos solos cultivados com cajueiro no Piaui; Correcao do solo; Recomendacoesbitstream/CNPAT-2010/8606/1/Dc-081.pd
APEnet+: high bandwidth 3D torus direct network for petaflops scale commodity clusters
We describe herein the APElink+ board, a PCIe interconnect adapter featuring
the latest advances in wire speed and interface technology plus hardware
support for a RDMA programming model and experimental acceleration of GPU
networking; this design allows us to build a low latency, high bandwidth PC
cluster, the APEnet+ network, the new generation of our cost-effective,
tens-of-thousands-scalable cluster network architecture. Some test results and
characterization of data transmission of a complete testbench, based on a
commercial development card mounting an Altera FPGA, are provided.Comment: 6 pages, 7 figures, proceeding of CHEP 2010, Taiwan, October 18-2
Etiological diagnosis, prognostic significance and role of electrophysiological study in patients with Brugada ECG and syncope.
BACKGROUND: Syncope is considered a risk factor for life-threatening arrhythmias in Brugada patients. Distinguishing a benign syncope from one due to ventricular arrhythmias is often difficult, unless an ECG is recorded during the episode. Aim of the study was to analyze the characteristics of syncopal episodes in a large population of Brugada patients and evaluate the role of electrophysiological study (EPS) and the prognosis in the different subgroups. METHODS AND RESULTS: One hundred ninety-five Brugada patients with history of syncope were considered. Syncope were classified as neurally mediated (group 1, 61%) or unexplained (group 2, 39%) on the basis of personal and family history, clinical features, triggers, situations, associated signs, concomitant therapy. Most patients underwent EPS; they received ICD or implantable loop-recorder on the basis of the result of investigations and physician's judgment. At 62±45months of mean follow-up, group 1 showed a significantly lower incidence of arrhythmic events (2%) as compared to group 2 (9%, p<0.001). Group 2 patients with positive EPS showed the highest risk of arrhythmic events (27%). No ventricular events occurred in subjects with negative EPS. CONCLUSION: Etiological definition of syncope in Brugada patients is important, as it allows identifying two groups with different outcome. Patients with unexplained syncope and ventricular fibrillation induced at EPS have the highest risk of arrhythmic events. Patients presenting with neurally mediated syncope showed a prognosis similar to that of the asymptomatic and the role of EPS in this group is unproven
NaNet: a Low-Latency, Real-Time, Multi-Standard Network Interface Card with GPUDirect Features
While the GPGPU paradigm is widely recognized as an effective approach to
high performance computing, its adoption in low-latency, real-time systems is
still in its early stages.
Although GPUs typically show deterministic behaviour in terms of latency in
executing computational kernels as soon as data is available in their internal
memories, assessment of real-time features of a standard GPGPU system needs
careful characterization of all subsystems along data stream path.
The networking subsystem results in being the most critical one in terms of
absolute value and fluctuations of its response latency.
Our envisioned solution to this issue is NaNet, a FPGA-based PCIe Network
Interface Card (NIC) design featuring a configurable and extensible set of
network channels with direct access through GPUDirect to NVIDIA Fermi/Kepler
GPU memories.
NaNet design currently supports both standard - GbE (1000BASE-T) and 10GbE
(10Base-R) - and custom - 34~Gbps APElink and 2.5~Gbps deterministic latency
KM3link - channels, but its modularity allows for a straightforward inclusion
of other link technologies.
To avoid host OS intervention on data stream and remove a possible source of
jitter, the design includes a network/transport layer offload module with
cycle-accurate, upper-bound latency, supporting UDP, KM3link Time Division
Multiplexing and APElink protocols.
After NaNet architecture description and its latency/bandwidth
characterization for all supported links, two real world use cases will be
presented: the GPU-based low level trigger for the RICH detector in the NA62
experiment at CERN and the on-/off-shore data link for KM3 underwater neutrino
telescope
PerĂodo apropriado para a substituição de copa do cajueiro anĂŁo precoce ou para a enxertia direta no campo.
O estudo tem o objetivo de apresentar uma alternativa para formacĂŁo de pomares de cajueiro anĂŁo precoce, em razĂŁo da grande dificuldade de disponibilidade de mudas enxertadas a Ă©poca prĂłpria para plantio.bitstream/CNPAT-2010/11938/1/Pa-044.pd
Custo comparativo de três fontes de matéria orgânica e uma poliacrilamida utilizadas como condicionadores de solo na produção do meloeiro.
Custo comparativo de três fontes de matéria orgânica e uma poliacrilamida utilizadas como condicionadores de solo na produção do meloeiro.bitstream/CNPAT-2010/5297/1/Ct-015.pd
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