GUIDE Three-Schema Architecture [SD-23] - Just a background reference document. Cite in the bibliography.

ANSI/SPARC and ISO Three-Schema Architecture - Conceptual Schema and Information Base [TR9007] - We need at least a small clause on three-schema, and these should be references therein. This will enable us to talk about the focus on CS, but also note the differentiation with IS and ES and the (potential) need to map all three in a complete three-schema DD.

ANSI Information Resource Dictionary System (IRDS) [X3.138-1988] - Very early thinking on relational DDs. Not really relevant anymore.

ISO Reference Model of Data Management (RMDM) [10032] - Only useful part might be the leveling/level pair aspects, perhaps as a point to be addressed in the guidelines.

ISO Information Resource Dictionary System (IRDS) [10027 and 10728] - Strictly EAR-relational-based, so its meta structures are not sufficient. However, some aspects of the configuration management services and other similar services might be relevant to, or referenced in, the guidelines.

ISO Portable Common Tool Environment (PCTE) [13719-n] - Semi-object-based, but still really EAR at the meta-structure level. This standard is fairly implementation-oriented; in the guidelines we might refer to the PCTE architecture as an example in the sense of potential implementation architectures, but implementation is really outside the scope of the ITS DD standard itself.

ISO CASE Data Interchange Format (CDIF) [15474-n to 15479-n] - Its EAR-based meta structures are not sufficient. The CDIF interchange syntax might be looked at as a source for the message set template syntax expression mechanism, depending upon the outcome of the ASN.1 discussions. Might note (probably in the guidelines) that for any subsystem DD that uses a more-limited, specialized modeling approach (like EAR, NIAM, OO), the content meta models for those modeling paradigms might well have been standardized as part of the CDIF effort and could be a source for doing meta-meta representation and translation using the deeper meta structures of the ITS DD standard.

IEEE Meta Data - No formal standard. Deals mostly with custom meta data for scientific and technical data sets. Only common aspect seems to be the use of geospatial standards, the same ones of which are already addressed in relevant ITS documents such as the Federal Transit Administration (FTA) - National Transit Geographical Information Systems (GIS) Manual and the APTS [ITS subsystem DD] Map Database User Requirements Specification.

Object Management Group (OMG) Open Repository RFP - This is a proprietary, industry consortium document, not a standard per se. I do not know what kind of responses OMG received to the RFP, but the RFP clearly assumed an object-oriented approach. We view OO as a limited, specialized approach at the meta-structure level, but particular OO environments might be useful as candidate IS technology corresponding to some implementations of ITS DD CSs. On the whole, this has no real relevance to the ITS DD standard and guidelines except perhaps in the area of the repository services requested in the RFP. However, a brief validation exercise indicated that these same services are addressed in the ISO IRDS, PCTE and 11179 standards.

ISO Data Element Specification [11179-n] - On the whole, we believe the ITS DD meta structure approach should be reasonably consistent with this, but it should be more formal, more explicit, better organized (allowing more rigorous, unambiguous concept descriptions and better separation of concepts), and will likely need to go beyond the structures in this standard. For example, there needs to be better separation of presentation, implementation and conceptual aspects of data, as well as the intensional (intrinsic) and extensional (more database oriented) attributes of data concepts. Our initial review indicates the following:

Part 1 - This framework is useful background and overview material on IS 11179 and is intended to provide users of the standard a way to understand the specific roles and interrelationships of the other five parts. Some of the definitions might be useful for terminology, but many are very tightly-coupled with the meta structures of IS 11179, and may not have wide-acceptance or applicability as 'standard definitions'. The meta structures are covered in bits and pieces in several places, including this part and part 5. We believe they tend to collapse certain core semantics which should be separated out, and are insufficient for specifying the semantics of data at a depth sufficient to support the meaningful interchange envisioned among the ITS DDs. It should be noted that the meta structures are more explicitly defined in a separate, draft ANSI standard which is not yet the subject of international standardization.

Part 2 - This classification scheme deals with the contents of a data dictionary, albeit at a fairly general, abstract level. It is outside the scope of the ITS DD standard and guidelines. The standard and/or guidelines may well, however, explain and give examples of how such contents can be populated into a DD, using the meta structures of the ITS DD standard If particular ITS DD specifiers are interested in such contents, there are numerous references to contents of this kind. This particular classification scheme has not been applied, to our knowledge, outside the SC14 community.

Part 3 - Many of the 'meta data attributes' may be useful for data administration functions. They should at least be addressed in the guidelines. Their formal structure will also need to be specified in the ITS DD standard.

Part 4 - Some of these rules for naming and specifying data elements may be good general guidelines, and should be considered for reference or inclusion in some way in the ITS DD guidelines. Structured semantics, however, are not really addressed here, as most of the semantics are conveyed in natural languages associated with the data element, not in some explicit, formal specification. This means they would not be easily accessible in a data dictionary or message without either extensive human involvement, or hardcoded translation (which is effectively what the current EDI technologies do). That's a limiting approach.

Part 5 - Naming conventions are likely outside the scope of the overall ITS standard, although some of the general guidelines for naming included here might be useful for the ITS DD guidelines. The specifics of the naming conventions here depend on the specific meta structures of IS 11179, as commented on above. This depends on whether the WG would support, or even has a need for, a single naming convention. That might be necessary or useful if all data is in a common registry or at least if some data is defined in a common ITS DD across subsystems, but in any case naming would be part of the specification of a data concept in a data dictionary.

Part 6 - The specifics of this part of the specification will be useful if not necessary should the ITS DD WG agree on the need for a central registry, at least to support data common across a number of ITS subsystems. The general approach might be useful in the guidelines even as a way for local subsystem DDs to exercise some control (in the data administrative sense) over the data in their local DD.

ANSI X3L8 Metamodel for Sharable Data - This is the draft ANSI standard noted in the discussion of IS 11179 Part 1 above. A more detailed review of this document will be done as part of the development of the proposed ITS DD meta structures. It is not officially part of IS 11179, although it can logically be considered part of that standard since this document presents, in more detail, the meta structures presumed to underlie IS 11179, but which are currently presented at a cursory level in that standard. The general sense is these can be used as one source, but they not be considered the only source.

SC14 Principles Document - Might be a useful source for some terminology, although some definitions may be too tied-in to the particulars of the ISO 11179 meta-model. It is not clear whether these are entirely consistent with the definitions in IS 11179, or even whether they supposed to be.

Proposed ITS Working Terminology - [DEFINI~1.DOC] from Andy Schoka (softcopy) - Based on notes from early pre-data dictionary project 'strike force' working meeting. Good starting point to be extended by the WG.

Burt Parker's Notes from ITS America Meeting on Data Registry and Configuration Management - [DATA REGISTRATION NOTES.DOC] and proposed data registry overview [REGIST~2.DOC] (softcopies). Useful for the guidelines.

Burt Parker's Technical Report on Concept of Operations for Data Element Registry - (hardcopy). Useful for the guidelines.

ANSI IRDS Conceptual Schema [X3/TR-14 Parts 1-2] - Cite in bibliography as background reference document for three-schema architecture.

ISO Conceptual Schema Modelling Facilities (CSMF) [14481] - The normative constructs might be considered as 'starter set' content for ITS DD's, but since this is content, not structure, it is technically outside the scope of the ITS DD standard. However, what we should do in the guidelines and/or the standard is explain (and show at least one example) of how one might use these normative constructs to describe (and register) high-level, general concepts. These might also be input to the classification work of the WG.

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