Fellow Working Group Members:
Attached please find an updated version of "Candidate
ITS Working Terminology for Data Dictionaries and Message
Sets," dated 4 March 1997. This version accommodates
a valuable contribution from Paul Hawes, the editor of ANSI X3.285
and participant in ASC X3L8, Data representation. The material
regarding message-related definitions has been reworked (thank
you Tom Kurihara) and supplemented so as to facilitate our next
discussions in the Working Group specifically dealing with message
set templates. Consider reviewing these definitions in preparation
for the meeting. In order to provide a perspective, I should say
that once this Working Group agrees with these definitions, the
paper is intended to be floated to the CSO participants in response
to a CSO action item.
See you at the meeting,
Abstract Syntax Notation One (ASN.1):
In general, ASN.1 refers to a standard notation for the definition
of data types and values along with encoding rules that produce
a transfer syntax for these values. The notation is specified
in ISO/IEC 8824: Specification of basic notation. The encoding
rules are specified in ISO/IEC 8825: ASN.1 Encoding Rules. ASN.1
is used for describing system interfaces. It encompasses both
a methodology (8824) for specifying the syntax of interface data
and encoding methods (8825) for producing actual messages to be
exchanged across the interface.
A characteristic of an object or entity. (ISO 11179-3)
A specific occurrence of an attribute. For example, "blue"
is an attribute value for the attribute "color".
A designation or description of the application environment or
discipline in which a name is applied. (ISO 11170-3)
A representation of facts, ideas, or instructions in a formalized
manner suitable for communication, interpretation, or processing
by humans or by machines. (This definition refers to a group of
facts taken as a unit, thus it is used with a singular verb.)
A collection of data elements treated as a unit.
The human perception of a property of an object set, identified
and described independently of any particular representation.
A specialized type of database containing metadata, which is managed
by a data dictionary system; a repository of information describing
the characteristics of data used to design, monitor, document,
protect, and control data in information systems and databases;
an application of data dictionary systems (DoDD 8320.1)
data dictionary system:
A software system for defining, creating, updating, processing,
and using data dictionaries.
1. A unit of data for which the definition, identification, representation,
and permissible values are specified by means of a set of attributes.
(ISO/IEC 11179-3) 2. A single unit of data that in a certain context
is considered indivisible. It cannot be decomposed into more fundamental
segments of data that have useful meaning within the scope of
data element dictionary:
An information resource that specifies, defines, and lists all
relevant data elements. (ISO/IEC 11179-3)
A description of the organization of data in a manner that reflects
an information structure.
A place to keep characteristics of data that are necessary to
clearly describe, inventory, analyze, and classify data. A data
registry supports data sharing with cross-system and cross-organization
descriptions of common units of data. A data registry assists
users of shared data to have a common understanding of a unit
of data's meaning, representation, and identification.
A single kind of data for which the identification and description
are identical for all occurrences. It may be a data composite
or a data element.
A category used to classify the collection of letters, digits,
and/or symbols to depict values of a data element based upon the
operations that may be performed on the data element.
A statement of the essential meaning of a person, thing, word
or word group, or a sign or symbol.
Words representing a person, thing, word, or word group, or a
sign or symbol intended to give a complete conceptual image. May
include a definition along with other characteristics.
A database application that contains information about systems,
organizations, networks, business processes, information flows,
and other facts about the enterprise's information resources.
In data communications, any thought or idea expressed in a form
suitable for transmission by any means of communication.
See message structure.
An organized list of messages, with reference to their locations
and relationships to other messages. Each message catalog shall
A predefined structure and order of message elements for use in
ITS messages. Each message format shall be registered.
See message structure.
A finite, defined set of messages for use in representing ITS
dataflows. A message list shall be registered.
The general layout and components of a message consisting of a
message header, message body, and message trailer. The message
header includes data about the entire message. The message body
includes information relating to the function and dataflow represented.
The message trailer includes data that marks the end of the message.
A reference pattern for the contents of each of the three message
components which may be used in its entirety or adapted for communicating
among ITS entities and components. See message structure. Each
instance of the use of a message template shall be registered.
See message structure.
A set of concepts, abstractions, or things in the natural world
that can be identified with explicit boundaries and meaning and
whose properties and behavior all follow the same rules.
Open Systems Interconnection--Reference Model (OSI-RM):
An abstract description of the digital communications between
application processes running in distinct systems. The model employs
a hierarchical structure of seven layers. Each layer performs
value-added service at the request of the adjacent higher layer
and, in turn, requests more basic services from the adjacent lower
One member of the allowed representations of a data element.
A set of one or more base standards and, where applicable, the
identification of chosen classes, conforming subsets, options
and parameters for those base standards necessary to accomplish
a particular function.
A classification of any feature that humans naturally use to distinguish
one individual object from another. It is any one of the charactistics
of an object class that humans use as a label, quantity, or description.
It has no particular associated means of representation by which
the property can be communicated.
A formal set of conventions governing the format and control of
interaction among communicating functional units. In layered communications
system architecture, a formal set of procedures that are adopted
to facilitate functional interoperation within the layered hierarchy.
protocol control information (PCI):
In OSI, information exchanged between entities of a given layer,
via the service provided by the next lower layer, to coordinate
their joint operation.
protocol data unit (PDU):
In OSI, a set of data specified in a protocol of a given layer
and consisting of protocol control information of that layer,
and possibly user data of that layer.
A term that helps define and render the name of a concept unique.
The assignment of an unambiguous identifier to a data element
in a way that makes the assignment available to interested parties.
registration authority (RA):
Any organization authorized to register data elements. (ISO/IEC
A designation of the position in the registration life-cycle of
a data element. (ISO/IEC 11179-6)
Business-based association between or among entities.
The part of a data element having a value domain, datatype, and,
if a quantity, a unit of quantity.
responsible organization (RO):
The organization or unit within an organization that is responsible
for the contents of the mandatory attributes by which the data
element is specified. (ISO/IEC 11179-6)
A description or representation of the structure of data.
In network architecture, the capabilities that a layer provides
to the adjacent layer closer to the end user. The service in a
given layer may depend upon services in layers closer to the media.
(ISO/IEC 2381-18) Rationale: The notion of a layer of the OSI
Reference Model providing services and the standards that define
those services should be described with the standards for protocols
and profiles. Concrete, abstract, and transfer syntax are used
by application functions as a means of communication with the
services provided by the layers of the OSI Reference Model.
submitting organization (SO):
The organization or unit within an organization that has submitted
the data element for addition, change or cancellation/withdrawal
in the data element dictionary. (ISO/IEC 11179-6)
A command, message, or input record that explicitly or implicitly
calls for a processing action, such as updating a file.
Restricted permissible values. It provides representation, but
has no implication as to what data concept the values are associated
nor what the values mean.
The definitions presented above come from a number of sources including a recent draft of the American National Standard Dictionary of Information Technology (ANSDIT). Since ANSDIT is in draft the definitions are subject to change and are only a starting point for refinement as appropriate to the ITS community. The dictionary is based on the American National Standard Dictionary of Information Systems, ANSI X3.172-1990 and its earlier editions and has been harmonized with ISO/IEC-2382, Information Technology - Vocabulary. Alternate sources include ISO/IEC 11179, Specification and Standardization of Data Elements; FS-1037C, Glossary of Telecommunications Terms which may be more appropriate within the ITS context. In other cases terms have been proposed by participants in the IEEE DD-Working Group as well as other groups.
end; 4 March 97
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