181 research outputs found
The multi-messenger search programme and results of the ANTARES neutrino telescope
The key-word of modern astronomy and astrophysics is multi-messenger: not only photons used as probes for the investigation of the Universe, but also cosmic-rays, neutrinos and gravitational waves. The multi-messenger approach is important in particular for neutrino detectors: potential astrophysical sources are predicted to emit a very faint neutrino signal and the presence of an isotropic flux of atmospheric background requires the development of effective search strategies. The multi-messenger approach can increase the discovery potential, the statistical significance of the observations and the efficiency of the detection. The advantages of the multi-messenger approach are evident, in particular, when looking at transient or flaring sources. In ANTARES, a wide programme of multi-messenger searches is active; the most relevant results will be presented in this contribution
The pLISA project in ASTERICS
In the framework of Horizon 2020, the European Commission approved the ASTERICS initiative (ASTronomy ESFRI and Research Infrastructure CluSter) to collect knowledge and experiences from astronomy, astrophysics and particle physics and foster synergies among existing research infrastructures and scientific communities, hence paving the way for future ones. ASTERICS aims at producing a common set of tools and strategies to be applied in Astronomy ESFRI facilities. In particular, it will target the so-called multi-messenger approach to combine information from optical and radio telescopes, photon counters and neutrino telescopes. pLISA is a software tool under development in ASTERICS to help and promote machine learning as a unified approach to multivariate analysis of astrophysical data and signals. The library will offer a collection of classification parameters, estimators, classes and methods to be linked and used in reconstruction programs (and possibly also extended), to characterize events in terms of particle identification and energy. The pLISA library aims at offering the software infras tructure for applications developed inside different experiments and has been designed with an effort to extrapolate general, physics-related estimators from the specific features of the data model related to each particular experiment. pLISA is oriented towards parallel computing architectures, with awareness of the opportunity of using GPUs as accelerators demanding specifically optimized algorithms and to reduce the costs of pro cessing hardware requested for the reconstruction tasks. Indeed, a fast (ideally, real-time) reconstruction can open the way for the development or improvement of alert systems, typically required by multi-messenger search programmes among the different experi mental facilities involved in ASTERICS
The Brain on Low Power Architectures - Efficient Simulation of Cortical Slow Waves and Asynchronous States
Efficient brain simulation is a scientific grand challenge, a
parallel/distributed coding challenge and a source of requirements and
suggestions for future computing architectures. Indeed, the human brain
includes about 10^15 synapses and 10^11 neurons activated at a mean rate of
several Hz. Full brain simulation poses Exascale challenges even if simulated
at the highest abstraction level. The WaveScalES experiment in the Human Brain
Project (HBP) has the goal of matching experimental measures and simulations of
slow waves during deep-sleep and anesthesia and the transition to other brain
states. The focus is the development of dedicated large-scale
parallel/distributed simulation technologies. The ExaNeSt project designs an
ARM-based, low-power HPC architecture scalable to million of cores, developing
a dedicated scalable interconnect system, and SWA/AW simulations are included
among the driving benchmarks. At the joint between both projects is the INFN
proprietary Distributed and Plastic Spiking Neural Networks (DPSNN) simulation
engine. DPSNN can be configured to stress either the networking or the
computation features available on the execution platforms. The simulation
stresses the networking component when the neural net - composed by a
relatively low number of neurons, each one projecting thousands of synapses -
is distributed over a large number of hardware cores. When growing the number
of neurons per core, the computation starts to be the dominating component for
short range connections. This paper reports about preliminary performance
results obtained on an ARM-based HPC prototype developed in the framework of
the ExaNeSt project. Furthermore, a comparison is given of instantaneous power,
total energy consumption, execution time and energetic cost per synaptic event
of SWA/AW DPSNN simulations when executed on either ARM- or Intel-based server
platforms
Gaussian and exponential lateral connectivity on distributed spiking neural network simulation
We measured the impact of long-range exponentially decaying intra-areal
lateral connectivity on the scaling and memory occupation of a distributed
spiking neural network simulator compared to that of short-range Gaussian
decays. While previous studies adopted short-range connectivity, recent
experimental neurosciences studies are pointing out the role of longer-range
intra-areal connectivity with implications on neural simulation platforms.
Two-dimensional grids of cortical columns composed by up to 11 M point-like
spiking neurons with spike frequency adaption were connected by up to 30 G
synapses using short- and long-range connectivity models. The MPI processes
composing the distributed simulator were run on up to 1024 hardware cores,
hosted on a 64 nodes server platform. The hardware platform was a cluster of
IBM NX360 M5 16-core compute nodes, each one containing two Intel Xeon Haswell
8-core E5-2630 v3 processors, with a clock of 2.40 G Hz, interconnected through
an InfiniBand network, equipped with 4x QDR switches.Comment: 9 pages, 9 figures, added reference to final peer reviewed version on
conference paper and DO
Real-time cortical simulations: energy and interconnect scaling on distributed systems
We profile the impact of computation and inter-processor communication on the
energy consumption and on the scaling of cortical simulations approaching the
real-time regime on distributed computing platforms. Also, the speed and energy
consumption of processor architectures typical of standard HPC and embedded
platforms are compared. We demonstrate the importance of the design of
low-latency interconnect for speed and energy consumption. The cost of cortical
simulations is quantified using the Joule per synaptic event metric on both
architectures. Reaching efficient real-time on large scale cortical simulations
is of increasing relevance for both future bio-inspired artificial intelligence
applications and for understanding the cognitive functions of the brain, a
scientific quest that will require to embed large scale simulations into highly
complex virtual or real worlds. This work stands at the crossroads between the
WaveScalES experiment in the Human Brain Project (HBP), which includes the
objective of large scale thalamo-cortical simulations of brain states and their
transitions, and the ExaNeSt and EuroExa projects, that investigate the design
of an ARM-based, low-power High Performance Computing (HPC) architecture with a
dedicated interconnect scalable to million of cores; simulation of deep sleep
Slow Wave Activity (SWA) and Asynchronous aWake (AW) regimes expressed by
thalamo-cortical models are among their benchmarks.Comment: 8 pages, 8 figures, 4 tables, submitted after final publication on
PDP2019 proceedings, corrected final DOI. arXiv admin note: text overlap with
arXiv:1812.04974, arXiv:1804.0344
Studio di un urto anelastico: una proposta per le Scuole Secondarie di II grado nell'ambito del progetto "Lab2Go"
When a free falling ping-pong ball collides on a horizontal surface, it loses kinetic energy. The ratio between the height reached by the ball after the collision and the initial height is called restitution coefficient. A method to measure it by using a home-made cathetometer was proposed during the Olimpiadi di Fisica 2018. In this paper we show how to measure it also by using the PhyPhox app and Arduino boar
Cobrawap: A pipeline for the analysis of wave activity at different brain states
Plenary talk at "WP2 Meeting: Networks underlying consciousness and cognition" held in Barcelona, Spain, from 19 to 21 June, 2023.Progetto EBRAINS-Italy IR00011, CUP B51E2200015006,Missione 4 - Istruzione e Ricerca, Componente 2, Azione 3.1.1
Funded by EU
Performance of the First ANTARES Detector Line
In this paper we report on the data recorded with the first Antares detector
line. The line was deployed on the 14th of February 2006 and was connected to
the readout two weeks later. Environmental data for one and a half years of
running are shown. Measurements of atmospheric muons from data taken from
selected runs during the first six months of operation are presented.
Performance figures in terms of time residuals and angular resolution are
given. Finally the angular distribution of atmospheric muons is presented and
from this the depth profile of the muon intensity is derived.Comment: 14 pages, 9 figure
Il progetto Lab2Go per la diffusione della pratica laboratoriale nelle Scuole Secondarie di II grado
Even if laboratory practice is essential for all scientific branches of knowledge, it is often neglected at High School, due to lack of time and/or resources. To establish a closer contact between school and experimental sciences, Sapienza Università di Roma and the Istituto Nazionale di Fisica Nucleare (INFN) launched the Lab2Go project, with the goal of spreading laboratory practice among students and teachers in high schools
A search for time dependent neutrino emission from microquasars with the ANTARES telescope
Results are presented on a search for neutrino emission from a sample of six microquasars, based on the data collected by the ANTARES neutrino telescope between 2007 and 2010. By means of appropriate time cuts, the neutrino search has been restricted to the periods when the acceleration of relativistic jets was taking place at the microquasars under study. The time cuts have been chosen using the information from the X-ray telescopes RXTE/ASM and Swift/BAT, and, in one case, the gamma-ray telescope Fermi/LAT. No statistically significant excess has been observed, thus upper limits on the neutrino fluences have been derived and compared to the predictions by models. Constraints have been put on the ratio of proton to electron luminosity in the jets
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