The Consultative Committee for Space Data Systems (CCSDS) completed its bi-annual international workshops in Houston, Texas, over the period May 4 through May 15, 1998. This issue of "NOST News" highlights results from Panel 2, which addresses information interchange.
Here are many of the attendants at the close of the workshop. From
left to right:
Back Row:
Robert Stephens, Claude Huc, Lou Reich, John Garrett, Simon Marshall, Denis
Minguillon, Terry Longstreth, Gian Maria Pinna, Patrick Mazal
Front Row:
David Giaretta, Nestor Peccia, Donald Sawyer
Missing:
Mike Martin, Bruce Ambacher, Yoshio Inoue, Katy Zhang, Xu XuDong
In the area of requirements and new work items, a proposal was made and accepted to investigate the use of Java as a Data Description Language. This effort will initially be supported by participation from the British National Space Agency.
Workshop participants study information exchange.
In the area of data administration, a particular focus was on the role of universal names/identifiers in various contexts. The CCSDS Control Authority offices assign universal identifiers to data descriptions and this process is also an ISO assignment process. Issues under review include the utility of ensuring these identifiers are recognized in the context of all ISO registered organizations and whether the Control Authority assignments should be extended to include identification of agreements between agencies related to the provision of satellite operations services. Another issue is whether the draft Internet Universal Resource Name (URN) should be prototyped using the Control Authority identifiers. A CCSDS-wide Naming and Addressing Working Group was established, led by NOST, to investigate naming issues including the impact of extending the Internet into space.
In the area of data structures, concept papers have been solicited to address the standardization of the widely used "Voldesc.sfd" file name; the identification of software as a type of description class; and the use of descriptions for data which has been multiply encoded.
In the area of languages, extensions to the CCSDS/ISO standard Parameter Value Language (PVL) have been proposed. The primary extensions are the preservation of statement ordering and the use of an extended, or alternate, character set. Impact on existing parsers and applications, including relationships to the Planetary Data System Object Description Language, needs to be considered. Relationships to the emerging XML language also need to be considered.
A related language standard is the draft Data Entity Dictionary Specification Language (DEDSL). This standard is proposed as a multi-discipline standard for the development of discipline dictionaries as well as for support of the semantics associated with data product instances. Efforts were begun last year to harmonize DEDSL with the conceptual data element standard ISO 1179. This has been largely superseded by the draft ANSI standard X3.285, which was developed by the same group (NCITS L8) and is being implemented by several federal agencies including the Environmental Protection Agency. Editing of the DEDSL is supported by CNES participation, while liaison with ANSI NCITS L8 is supported by NOST. Readers should contact NOST if they would like to participate in a Data Entity Dictionary Interest Group to track and influence standards development and to facilitate broader and more effective NASA Data Entity Dictionary usage across the disciplines.
In the area of software implementations, CNES has provided updated software for the generation and interpretation of EAST data description language files. These can be found from the CCSDS Panel 2 home page.
Finally, in the area of archive standards, the draft standard Reference Model for an Open Archival Information System (OAIS) was reviewed, and recommended changes were identified. The next version is expected in August 1998, and formal ISO and agency reviews are expected by the end of the year. This effort continues to attract wide attention and support by communities in addition to the space communities.
Participation in these activities is encouraged. Please contact Donald Sawyer or John Garrett for further information.
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John Garrett Goddard Space Flight Center Code 633 Greenbelt, MD 20771 United States Telephone: +1.301.286.3575 E-mail: John.Garrett@gsfc.nasa.gov FAX: +1.301.286.1771 |
Donald Sawyer Goddard Space Flight Center Code 633 Greenbelt, MD 20771 United States Telephone: +1.301.286.2748 E-mail: Donald.Sawyer@gsfc.nasa.gov FAX: +1.301.286.1771 |
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Editor:Miranda Beall