191 research outputs found
A Virtual Observatory Vision based on Publishing and Virtual Data
We would like to propose a vision of the Virtual Observatory where the "killer-app" is seen to be
generalizing and extending the idea of "publication" from the narrow meaning of peer-reviewed
journals. Here, publication ranges from private temporary storage, to group access, to public
access, through to data that supports peer-reviewed Journal papers in perpetuity. The publication
model is further extended by the possibility of Virtual Data -- where only the method of
computation is stored, not necessarily the data itself. Furthermore, virtual data products may
depend on other virtual data products, creating an implicit network of on-demand computation.
This computation may take huge resources, or it may be all within a laptop
Search and Discovery Tools for Astronomical On-line Resources and Services
A growing number of astronomical resources and data or information services
are made available through the Internet. However valuable information is
frequently hidden in a deluge of non-pertinent or non up-to-date documents. At
a first level, compilations of astronomical resources provide help for
selecting relevant sites. Combining yellow-page services and meta-databases of
active pointers may be an efficient solution to the data retrieval problem.
Responses generated by submission of queries to a set of heterogeneous
resources are difficult to merge or cross-match, because different data
providers generally use different data formats: new endeavors are under way to
tackle this problem. We review the technical challenges involved in trying to
provide general search and discovery tools, and to integrate them through upper
level interfaces.Comment: 7 pages, 2 Postscript figures; to be published in A&A
IVOA Recommendation: Simple Cone Search Version 1.03
This specification defines a simple query protocol for retrieving records
from a catalog of astronomical sources. The query describes sky position and an
angular distance, defining a cone on the sky. The response returns a list of
astronomical sources from the catalog whose positions lie within the cone,
formatted as a VOTable. This version of the specification is essentially a
transcription of the original Cone Search specification in order to move it
into the IVOA standardization process
Running a distributed virtual observatory: US Virtual Astronomical Observatory operations
Operation of the US Virtual Astronomical Observatory shares some issues with
modern physical observatories, e.g., intimidating data volumes and rapid
technological change, and must also address unique concerns like the lack of
direct control of the underlying and scattered data resources, and the
distributed nature of the observatory itself. In this paper we discuss how the
VAO has addressed these challenges to provide the astronomical community with a
coherent set of science-enabling tools and services. The distributed nature of
our virtual observatory-with data and personnel spanning geographic,
institutional and regime boundaries-is simultaneously a major operational
headache and the primary science motivation for the VAO. Most astronomy today
uses data from many resources. Facilitation of matching heterogeneous datasets
is a fundamental reason for the virtual observatory. Key aspects of our
approach include continuous monitoring and validation of VAO and VO services
and the datasets provided by the community, monitoring of user requests to
optimize access, caching for large datasets, and providing distributed storage
services that allow user to collect results near large data repositories. Some
elements are now fully implemented, while others are planned for subsequent
years. The distributed nature of the VAO requires careful attention to what can
be a straightforward operation at a conventional observatory, e.g., the
organization of the web site or the collection and combined analysis of logs.
Many of these strategies use and extend protocols developed by the
international virtual observatory community.Comment: 7 pages with 2 figures included within PD
IVOA Recommendation: Resource Metadata for the Virtual Observatory Version 1.12
An essential capability of the Virtual Observatory is a means for describing
what data and computational facilities are available where, and once
identified, how to use them. The data themselves have associated metadata
(e.g., FITS keywords), and similarly we require metadata about data collections
and data services so that VO users can easily find information of interest.
Furthermore, such metadata are needed in order to manage distributed queries
efficiently; if a user is interested in finding x-ray images there is no point
in querying the HST archive, for example. In this document we suggest an
architecture for resource and service metadata and describe the relationship of
this architecture to emerging Web Services standards. We also define an initial
set of metadata concepts
The organization and management of the Virtual Astronomical Observatory
The U.S. Virtual Astronomical Observatory (VAO; http://www.us-vao.org/) has
been in operation since May 2010. Its goal is to enable new science through
efficient integration of distributed multi-wavelength data. This paper
describes the management and organization of the VAO, and emphasizes the
techniques used to ensure efficiency in a distributed organization. Management
methods include using an annual program plan as the basis for establishing
contracts with member organizations, regular communication, and monitoring of
processes.Comment: 9 pages, 3 figures. SPIE Conference 8449: Modeling, Systems
Engineering, and Project Management for Astronomy
Astronomical Software Directory Service
With the support of NASA's Astrophysics Data Program (NRA 92-OSSA-15), we have developed the Astronomical Software Directory Service (ASDS): a distributed, searchable, WWW-based database of software packages and their related documentation. ASDS provides integrated access to 56 astronomical software packages, with more than 16,000 URLs indexed for full-text searching. Users are performing about 400 searches per month. A new aspect of our service is the inclusion of telescope and instrumentation manuals, which prompted us to change the name to the Astronomical Software and Documentation Service. ASDS was originally conceived to serve two purposes: to provide a useful Internet service in an area of expertise of the investigators (astronomical software), and as a research project to investigate various architectures for searching through a set of documents distributed across the Internet. Two of the co-investigators were then installing and maintaining astronomical software as their primary job responsibility. We felt that a service which incorporated our experience in this area would be more useful than a straightforward listing of software packages. The original concept was for a service based on the client/server model, which would function as a directory/referral service rather than as an archive. For performing the searches, we began our investigation with a decision to evaluate the Isite software from the Center for Networked Information Discovery and Retrieval (CNIDR). This software was intended as a replacement for Wide-Area Information Service (WAIS), a client/server technology for performing full-text searches through a set of documents. Isite had some additional features that we considered attractive, and we enjoyed the cooperation of the Isite developers, who were happy to have ASDS as a demonstration project. We ended up staying with the software throughout the project, making modifications to take advantage of new features as they came along, as well as influencing the software development. The Web interface to the search engine is provided by a gateway program written in C++ by a consultant to the project (A. Warnock)
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