35,735 research outputs found
Advanced Architectures for Astrophysical Supercomputing
Astronomers have come to rely on the increasing performance of computers to
reduce, analyze, simulate and visualize their data. In this environment, faster
computation can mean more science outcomes or the opening up of new parameter
spaces for investigation. If we are to avoid major issues when implementing
codes on advanced architectures, it is important that we have a solid
understanding of our algorithms. A recent addition to the high-performance
computing scene that highlights this point is the graphics processing unit
(GPU). The hardware originally designed for speeding-up graphics rendering in
video games is now achieving speed-ups of in general-purpose
computation -- performance that cannot be ignored. We are using a generalized
approach, based on the analysis of astronomy algorithms, to identify the
optimal problem-types and techniques for taking advantage of both current GPU
hardware and future developments in computing architectures.Comment: 4 pages, 1 figure, to appear in the proceedings of ADASS XIX, Oct 4-8
2009, Sapporo, Japan (ASP Conf. Series
Unleashing the Power of Distributed CPU/GPU Architectures: Massive Astronomical Data Analysis and Visualization case study
Upcoming and future astronomy research facilities will systematically
generate terabyte-sized data sets moving astronomy into the Petascale data era.
While such facilities will provide astronomers with unprecedented levels of
accuracy and coverage, the increases in dataset size and dimensionality will
pose serious computational challenges for many current astronomy data analysis
and visualization tools. With such data sizes, even simple data analysis tasks
(e.g. calculating a histogram or computing data minimum/maximum) may not be
achievable without access to a supercomputing facility.
To effectively handle such dataset sizes, which exceed today's single machine
memory and processing limits, we present a framework that exploits the
distributed power of GPUs and many-core CPUs, with a goal of providing data
analysis and visualizing tasks as a service for astronomers. By mixing shared
and distributed memory architectures, our framework effectively utilizes the
underlying hardware infrastructure handling both batched and real-time data
analysis and visualization tasks. Offering such functionality as a service in a
"software as a service" manner will reduce the total cost of ownership, provide
an easy to use tool to the wider astronomical community, and enable a more
optimized utilization of the underlying hardware infrastructure.Comment: 4 Pages, 1 figures, To appear in the proceedings of ADASS XXI, ed.
P.Ballester and D.Egret, ASP Conf. Serie
GPU-Based Volume Rendering of Noisy Multi-Spectral Astronomical Data
Traditional analysis techniques may not be sufficient for astronomers to make
the best use of the data sets that current and future instruments, such as the
Square Kilometre Array and its Pathfinders, will produce. By utilizing the
incredible pattern-recognition ability of the human mind, scientific
visualization provides an excellent opportunity for astronomers to gain
valuable new insight and understanding of their data, particularly when used
interactively in 3D. The goal of our work is to establish the feasibility of a
real-time 3D monitoring system for data going into the Australian SKA
Pathfinder archive.
Based on CUDA, an increasingly popular development tool, our work utilizes
the massively parallel architecture of modern graphics processing units (GPUs)
to provide astronomers with an interactive 3D volume rendering for
multi-spectral data sets. Unlike other approaches, we are targeting real time
interactive visualization of datasets larger than GPU memory while giving
special attention to data with low signal to noise ratio - two critical aspects
for astronomy that are missing from most existing scientific visualization
software packages. Our framework enables the astronomer to interact with the
geometrical representation of the data, and to control the volume rendering
process to generate a better representation of their datasets.Comment: 4 pages, 1 figure, to appear in the proceedings of ADASS XIX, Oct 4-8
2009, Sapporo, Japan (ASP Conf. Series
The stellar content of the infalling molecular clump G286.21+0.17
The early evolution during massive star cluster formation is still uncertain.
Observing embedded clusters at their earliest stages of formation can provide
insight into the spatial and temporal distribution of the stars and thus probe
different star cluster formation models. We present near-infrared imaging of an
8'*13'(5.4pc*8.7pc) region around the massive infalling clump G286.21+0.17(also
known as BYF73). The stellar content across the field is determined and
photometry is derived in order to { obtain} stellar parameters for the cluster
members. We find evidence for some sub-structure (on scales less than a pc
diameter) within the region with apparently at least three different
sub-clusters associated with the molecular clump based on differences in
extinction and disk fractions. At the center of the clump we identify a deeply
embedded sub-cluster. Near-infrared excess is detected for 39-44% in the two
sub-clusters associated with molecular material and 27% for the exposed
cluster. Using the disk excess as a proxy for age this suggests the clusters
are very young. The current total stellar mass is estimated to be at least 200
Msun. The molecular core hosts a rich population of pre-main sequence stars.
There is evidence for multiple events of star formation both in terms of the
spatial distribution within the star forming region and possibly from the disk
frequency.Comment: Submitted to A
Coordinate Confusion in Conformal Cosmology
A straight-forward interpretation of standard
Friedmann-Lemaitre-Robertson-Walker (FLRW) cosmologies is that objects move
apart due to the expansion of space, and that sufficiently distant galaxies
must be receding at velocities exceeding the speed of light. Recently, however,
it has been suggested that a simple transformation into conformal coordinates
can remove superluminal recession velocities, and hence the concept of the
expansion of space should be abandoned. This work demonstrates that such
conformal transformations do not eliminate superluminal recession velocities
for open or flat matter-only FRLW cosmologies, and all possess superluminal
expansion. Hence, the attack on the concept of the expansion of space based on
this is poorly founded. This work concludes by emphasizing that the expansion
of space is perfectly valid in the general relativistic framework, however,
asking the question of whether space really expands is a futile exercise.Comment: 5 pages, accepted for publication in MNRAS Letter
Health and cancer prevention: knowledge and beliefs of children and young people
Objective: To collect information from children and young people about their knowledge of and attitudes towards cancer and their understanding of health and health related behaviours to inform future health promotion work. Design: Questionnaire survey of 15-16 year olds, and interviews with play materials with 9-10 year old children. Setting: Six inner city, suburban, and rural schools. Subjects: 226 children aged 15-16 years and 100 aged 9-10 years. Main outcome measures: Knowledge about different types of cancer; beliefs about health; sources of information; quality of research data obtainable from young children about cancer and health. Results: Both samples knew most about lung cancer, but there was also some knowledge of breast and skin cancer and leukaemia. Smoking, together with pollution and other environmental factors, were seen as the dominant causes of cancer. Environmental factors were mentioned more often by the inner city samples. Television and the media were the most important sources of information. Young people were more worried about unemployment than about ill health. More than half the young people did not describe their health as good, and most said they did not have a healthy lifestyle. Children were able to provide detailed information about their knowledge and understanding by using drawings as well as interviews. Conclusions: Children and young people possess considerable knowledge about cancer, especially about lung cancer and smoking, and show considerable awareness of predominant health education messages. Despite this knowledge, many lead less than healthy lifestyles. Health is not seen as the most important goal in life by many young people; the circumstances in which many children and young people live are not experienced as health promoting
Spotting Radio Transients with the help of GPUs
Exploration of the time-domain radio sky has huge potential for advancing our
knowledge of the dynamic universe. Past surveys have discovered large numbers
of pulsars, rotating radio transients and other transient radio phenomena;
however, they have typically relied upon off-line processing to cope with the
high data and processing rate. This paradigm rules out the possibility of
obtaining high-resolution base-band dumps of significant events or of
performing immediate follow-up observations, limiting analysis power to what
can be gleaned from detection data alone. To overcome this limitation,
real-time processing and detection of transient radio events is required. By
exploiting the significant computing power of modern graphics processing units
(GPUs), we are developing a transient-detection pipeline that runs in real-time
on data from the Parkes radio telescope. In this paper we discuss the
algorithms used in our pipeline, the details of their implementation on the GPU
and the challenges posed by the presence of radio frequency interference.Comment: 4 Pages. To appear in the proceedings of ADASS XXI, ed. P.Ballester
and D.Egret, ASP Conf. Serie
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