37,631 research outputs found
Application of graphics processing units to search pipelines for gravitational waves from coalescing binaries of compact objects
We report a novel application of a graphics processing unit (GPU) for the purpose of accelerating the search pipelines for gravitational waves from coalescing binaries of compact objects. A speed-up of 16-fold in total has been achieved with an NVIDIA GeForce 8800 Ultra GPU card compared with one core of a 2.5 GHz Intel Q9300 central processing unit (CPU). We show that substantial improvements are possible and discuss the reduction in CPU count required for the detection of inspiral sources afforded by the use of GPUs
A New Strategy for Deep Wide-Field High Resolution Optical Imaging
We propose a new strategy for obtaining enhanced resolution (FWHM = 0.12
arcsec) deep optical images over a wide field of view. As is well known, this
type of image quality can be obtained in principle simply by fast guiding on a
small (D = 1.5m) telescope at a good site, but only for target objects which
lie within a limited angular distance of a suitably bright guide star. For high
altitude turbulence this 'isokinetic angle' is approximately 1 arcminute. With
a 1 degree field say one would need to track and correct the motions of
thousands of isokinetic patches, yet there are typically too few sufficiently
bright guide stars to provide the necessary guiding information. Our proposed
solution to these problems has two novel features. The first is to use
orthogonal transfer charge-coupled device (OTCCD) technology to effectively
implement a wide field 'rubber focal plane' detector composed of an array of
cells which can be guided independently. The second is to combine measured
motions of a set of guide stars made with an array of telescopes to provide the
extra information needed to fully determine the deflection field. We discuss
the performance, feasibility and design constraints on a system which would
provide the collecting area equivalent to a single 9m telescope, a 1 degree
square field and 0.12 arcsec FWHM image quality.Comment: 46 pages, 22 figures, submitted to PASP, a version with higher
resolution images and other supplementary material can be found at
http://www.ifa.hawaii.edu/~kaiser/wfhr
ASCR/HEP Exascale Requirements Review Report
This draft report summarizes and details the findings, results, and
recommendations derived from the ASCR/HEP Exascale Requirements Review meeting
held in June, 2015. The main conclusions are as follows. 1) Larger, more
capable computing and data facilities are needed to support HEP science goals
in all three frontiers: Energy, Intensity, and Cosmic. The expected scale of
the demand at the 2025 timescale is at least two orders of magnitude -- and in
some cases greater -- than that available currently. 2) The growth rate of data
produced by simulations is overwhelming the current ability, of both facilities
and researchers, to store and analyze it. Additional resources and new
techniques for data analysis are urgently needed. 3) Data rates and volumes
from HEP experimental facilities are also straining the ability to store and
analyze large and complex data volumes. Appropriately configured
leadership-class facilities can play a transformational role in enabling
scientific discovery from these datasets. 4) A close integration of HPC
simulation and data analysis will aid greatly in interpreting results from HEP
experiments. Such an integration will minimize data movement and facilitate
interdependent workflows. 5) Long-range planning between HEP and ASCR will be
required to meet HEP's research needs. To best use ASCR HPC resources the
experimental HEP program needs a) an established long-term plan for access to
ASCR computational and data resources, b) an ability to map workflows onto HPC
resources, c) the ability for ASCR facilities to accommodate workflows run by
collaborations that can have thousands of individual members, d) to transition
codes to the next-generation HPC platforms that will be available at ASCR
facilities, e) to build up and train a workforce capable of developing and
using simulations and analysis to support HEP scientific research on
next-generation systems.Comment: 77 pages, 13 Figures; draft report, subject to further revisio
Processing optimization with parallel computing for the J-PET tomography scanner
The Jagiellonian-PET (J-PET) collaboration is developing a prototype TOF-PET
detector based on long polymer scintillators. This novel approach exploits the
excellent time properties of the plastic scintillators, which permit very
precise time measurements. The very fast, FPGA-based front-end electronics and
the data acquisition system, as well as, low- and high-level reconstruction
algorithms were specially developed to be used with the J-PET scanner. The
TOF-PET data processing and reconstruction are time and resource demanding
operations, especially in case of a large acceptance detector, which works in
triggerless data acquisition mode. In this article, we discuss the parallel
computing methods applied to optimize the data processing for the J-PET
detector. We begin with general concepts of parallel computing and then we
discuss several applications of those techniques in the J-PET data processing.Comment: 8 page
Very-high energy gamma-ray astronomy: A 23-year success story in high-energy astroparticle physics
Very-high energy (VHE) gamma quanta contribute only a minuscule fraction -
below one per million - to the flux of cosmic rays. Nevertheless, being neutral
particles they are currently the best "messengers" of processes from the
relativistic/ultra-relativistic Universe because they can be extrapolated back
to their origin. The window of VHE gamma rays was opened only in 1989 by the
Whipple collaboration, reporting the observation of TeV gamma rays from the
Crab nebula. After a slow start, this new field of research is now rapidly
expanding with the discovery of more than 150 VHE gamma-ray emitting sources.
Progress is intimately related with the steady improvement of detectors and
rapidly increasing computing power. We give an overview of the early attempts
before and around 1989 and the progress after the pioneering work of the
Whipple collaboration. The main focus of this article is on the development of
experimental techniques for Earth-bound gamma-ray detectors; consequently, more
emphasis is given to those experiments that made an initial breakthrough rather
than to the successors which often had and have a similar (sometimes even
higher) scientific output as the pioneering experiments. The considered energy
threshold is about 30 GeV. At lower energies, observations can presently only
be performed with balloon or satellite-borne detectors. Irrespective of the
stormy experimental progress, the success story could not have been called a
success story without a broad scientific output. Therefore we conclude this
article with a summary of the scientific rationales and main results achieved
over the last two decades.Comment: 45 pages, 38 figures, review prepared for EPJ-H special issue "Cosmic
rays, gamma rays and neutrinos: A survey of 100 years of research
Weak nonlinearities: A new route to optical quantum computation
Quantum information processing (QIP) offers the promise of being able to do
things that we cannot do with conventional technology. Here we present a new
route for distributed optical QIP, based on generalized quantum non-demolition
measurements, providing a unified approach for quantum communication and
computing. Interactions between photons are generated using weak
non-linearities and intense laser fields--the use of such fields provides for
robust distribution of quantum information. Our approach requires only a
practical set of resources, and it uses these very efficiently. Thus it
promises to be extremely useful for the first quantum technologies, based on
scarce resources. Furthermore, in the longer term this approach provides both
options and scalability for efficient many-qubit QIP.Comment: 7 Pages, 4 Figure
Accelerating Monte Carlo simulations with an NVIDIA® graphics processor
Modern graphics cards, commonly used in desktop computers, have evolved beyond a simple interface between processor and display to incorporate sophisticated calculation engines that can be applied to general purpose computing. The Monte Carlo algorithm for modelling photon transport in turbid media has been implemented on an NVIDIA® 8800gt graphics card using the CUDA toolkit. The Monte Carlo method relies on following the trajectory of millions of photons through the sample, often taking hours or days to complete. The graphics-processor implementation, processing roughly 110 million scattering events per second, was found to run more than 70 times faster than a similar, single-threaded implementation on a 2.67 GHz desktop computer
The ATLAS Trigger System Commissioning and Performance
The ATLAS trigger has been used very successfully to collect collision data
during 2009 and 2010 LHC running at centre of mass energies of 900 GeV, 2.36
TeV, and 7 TeV. This paper presents the ongoing work to commission the ATLAS
trigger with proton collisions, including an overview of the performance of the
trigger based on extensive online running. We describe how the trigger has
evolved with increasing LHC luminosity and give a brief overview of plans for
forthcoming LHC running.Comment: Poster at Hadron Collider Physics, Aug 2010, Toronto, Canada 4 pages,
6 figure
advligorts: The Advanced LIGO Real-Time Digital Control and Data Acquisition System
The Advanced LIGO detectors are sophisticated opto-mechanical devices. At the
core of their operation is feedback control. The Advanced LIGO project
developed a custom digital control and data acquisition system to handle the
unique needs of this new breed of astronomical detector. The advligorts is the
software component of this system. This highly modular and extensible system
has enabled the unprecedented performance of the LIGO instruments, and has been
a vital component in the direct detection of gravitational waves
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