Information Technology Reference
In-Depth Information
Advanced users can access additional features to create and change workflows
and to set con
gurations of grid infrastructures. These tools are also available
for standard users to not pose any a priori limitation on the workflow technology
usage.
Administrators are additionally enabled to manage all credentials, users, orga-
nizations, and communities.
The main characteristic of VisIVO portlets is to support high-performance,
multidimensional visualization of very large-scale astrophysical datasets. Users can
obtain meaningful visualizations rapidly while preserving full and intuitive control
of the relevant visualization parameters. Several VisIVO workflows were con
g-
ured to allow different basic tasks such as local or remote upload of datasets, and
creation of scienti
c user
interface portlets to enable easy parameter setting for standard users and to hide the
complexity of the underlying system and infrastructure. The WS-PGRADE portlets
are used from the workflow developers to create each VisIVO applications de
c movies. These workflows are provided with the speci
ned
as a gUSE concrete workflow and export them to the gUSE Application Repository.
In the application de
nition, all of the steps and the sequence of their execution are
con
gured except for the inputs and output ports that determine the location in
which the inputs should be retrieved and the output should be saved. These are
con
gured by the VisIVO portlets during the submission using the gUSE ASM
API.
Advanced users are able to adapt
c
problems by importing them from the gUSE application repository and working
directly with the WS-PGRADE portlets. The modularity, achieved by subdividing
the workflow into different tasks, ensures the reusability of the subtasks and pro-
vides more flexibility for the user. Standard users can upload and manage their
datasets through the VisIVO portlets without any knowledge about the totally
hidden grid infrastructure and middleware. In the following the VisIVO portlets are
described in more details.
The
VisIVO Importer
portlet converts user-supplied datasets into VisIVO binary
tables
2
(VBTs) without imposing any limits on size or dimensionality. It supports
conversion from several popular formats such as: ASCII and CSV, VOTables, or
FITS Tables. Both remote and local datasets can be uploaded, i.e., residing on a
remote URL or locally on a user
the VisIVO workflows to their speci
files the user must specify
URL and optionally a user name and password for authentication. Depending upon
the size of the datasets under consideration, remote uploads could take a long
period. To resolve this situation VisIVO Gateway allows an offline mode by means
of a workflow submission so that users can issue upload commands and then simply
close their current session. A follow-up e-mail gives noti
'
s computer. For remote
cation once the uploading
operation is completed. The portlet employs the gUSE ASM API to submit the
2
A VBT is a highly ef
cient data representation realized through a header
file (extension.
bin.
head
) containing all necessary metadata, and a raw data
file (extension.bin) storing actual data
values.
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