876 research outputs found
Survey and Analysis of Production Distributed Computing Infrastructures
This report has two objectives. First, we describe a set of the production
distributed infrastructures currently available, so that the reader has a basic
understanding of them. This includes explaining why each infrastructure was
created and made available and how it has succeeded and failed. The set is not
complete, but we believe it is representative.
Second, we describe the infrastructures in terms of their use, which is a
combination of how they were designed to be used and how users have found ways
to use them. Applications are often designed and created with specific
infrastructures in mind, with both an appreciation of the existing capabilities
provided by those infrastructures and an anticipation of their future
capabilities. Here, the infrastructures we discuss were often designed and
created with specific applications in mind, or at least specific types of
applications. The reader should understand how the interplay between the
infrastructure providers and the users leads to such usages, which we call
usage modalities. These usage modalities are really abstractions that exist
between the infrastructures and the applications; they influence the
infrastructures by representing the applications, and they influence the ap-
plications by representing the infrastructures
HotGrid: Graduated Access to Grid-based Science Gateways
We describe the idea of a Science Gateway, an application-specific task wrapped as a web service, and some examples of these that are being implemented on the US TeraGrid cyberinfrastructure. We also describe HotGrid, a means of providing simple, immediate access to the Grid through one of these gateways, which we hope will broaden the use of the Grid, drawing in a wide community of users. The secondary purpose of HotGrid is to acclimate a science community to the concepts of certificate use. Our system provides these weakly authenticated users with immediate power to use the Grid resources for science, but without the dangerous power of running arbitrary code. We describe the implementation of these Science Gateways with the Clarens secure web server
Grist: Grid-based Data Mining for Astronomy
The Grist project is developing a grid-technology based system as a research environment for astronomy with massive and complex datasets. This knowledge extraction system will consist of a library of distributed grid services controlled by a work ow system, compliant with standards emerging from the grid computing, web services, and virtual observatory communities. This new technology is being used to find high redshift quasars, study peculiar variable objects, search for transients in real time, and fit SDSS QSO spectra to measure black hole masses. Grist services are also a component of the "hyperatlas" project to serve high-resolution multi-wavelength imagery over the Internet. In support of these science and outreach objectives, the Grist framework will provide the enabling fabric to tie together distributed grid services in the areas of data access, federation, mining, subsetting, source extraction, image mosaicking, statistics, and visualization
Montage: a grid portal and software toolkit for science-grade astronomical image mosaicking
Montage is a portable software toolkit for constructing custom, science-grade
mosaics by composing multiple astronomical images. The mosaics constructed by
Montage preserve the astrometry (position) and photometry (intensity) of the
sources in the input images. The mosaic to be constructed is specified by the
user in terms of a set of parameters, including dataset and wavelength to be
used, location and size on the sky, coordinate system and projection, and
spatial sampling rate. Many astronomical datasets are massive, and are stored
in distributed archives that are, in most cases, remote with respect to the
available computational resources. Montage can be run on both single- and
multi-processor computers, including clusters and grids. Standard grid tools
are used to run Montage in the case where the data or computers used to
construct a mosaic are located remotely on the Internet. This paper describes
the architecture, algorithms, and usage of Montage as both a software toolkit
and as a grid portal. Timing results are provided to show how Montage
performance scales with number of processors on a cluster computer. In
addition, we compare the performance of two methods of running Montage in
parallel on a grid.Comment: 16 pages, 11 figure
Atlasmaker: A Grid-based Implementation of the Hyperatlas
The Atlasmaker project is using Grid technology, in combination with NVO
interoperability, to create new knowledge resources in astronomy. The product
is a multi-faceted, multi-dimensional, scientifically trusted image atlas of
the sky, made by federating many different surveys at different wavelengths,
times, resolutions, polarizations, etc. The Atlasmaker software does resampling
and mosaicking of image collections, and is well-suited to operate with the
Hyperatlas standard. Requests can be satisfied via on-demand computations or by
accessing a data cache. Computed data is stored in a distributed virtual file
system, such as the Storage Resource Broker (SRB). We expect these atlases to
be a new and powerful paradigm for knowledge extraction in astronomy, as well
as a magnificent way to build educational resources. The system is being
incorporated into the data analysis pipeline of the Palomar-Quest synoptic
survey, and is being used to generate all-sky atlases from the 2MASS, SDSS, and
DPOSS surveys for joint object detection.Comment: Published in the Proceedings of ADASS XI
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