Subject: Related Standards Efforts

From: BRUCE BARGMEYER 202-260-5306 <[email-masked]>
Date: Sun, 27 Mar 1994 11:20:00 -0500 (EST)

There are several ongoing standards that are relevant to the 
     topics discussed via this metadata reflector. I think that all 
     the efforts can be complimentary and produce a whole that is 
     greater than any of the efforts separately. The X3L8 and SC14 
     work tends to focus more on scalar data than on some of the more 
     complex scientific datasets. However, much of the work seems 
     relevant. In the Environmental Protection Agency, we must cover 
     the whole spectrum from data in traditional databases to the 
     terabyte/day of EOS data from NASA.
     
     I will send a few messages to the metadata reflector describing 
     some of the work of ANSI X3L8, Data Element Representation and 
     ISO SC 14, Data Element Principles. 
     
     As an overview, X3L8 together with ISO SC 14 is developing a six 
     part standard for data elements. The six parts are described 
     below. Some of the parts are considerably advanced beyond the 
     others. Part 3, on basic attributes of data elements, and part 4, 
     on data element definitions,  are proposed for Draft 
     International Standard status. Part 5, on naming is out for a 
     second Committee Draft ballot. Part 1, on framework, and Part 6, 
     on registration are early drafts.
     
     X3L8 is also developing a metamodel for data representation. I am 
     forward a draft of that metamodel as a Postscript file, and a 
     second postscript file describing the modeling notation.
     
     I have a reasonable ASCII version of the naming paper, but the 
     rest have a lot of format that is lost in translation, along with 
     the clarity that is conveyed by the format. I will try to send 
     clear text versions where possible, and Postscript versions for 
     better readibility. I will be out for the next week, so it may 
     take a while to get all the material forwarded to the reflector.
     
     The following  introduces each individual part of the multi-part 
     data specification standard (ISO/IEC 11179).  It summarizes main 
     points and discusses the importance of each. It is copied out of 
     Part 1, and will lose its format, fonts, etc. in this 
     transmission.
     
     The Framework for the Generation and Standardization of Data 
     Elements, Part 1 of ISO/IEC 11179, introduces and discusses 
     fundamental concepts of data elements essential to the 
     understanding of this set of standards; provides the context for 
     associating the individual parts of the standard; and provides 
     the overall glossary. 
     
     Classification of Concepts for the Identification of Domains, 
     Part 2 of ISO/IEC 11179, provides a taxonomic profile of a 

     special class of concepts called property terms.  This class of 
     concepts is sometimes called "class words" because they identify 
     the data class, or category, to which a data element belongs.  
     Sometime these terms are referred to as "headwords" because they 
     are the word of syntactic dominance in a data element name.  
     Examples include terms such as "color", "count", "code", "rate".  
     
     It is important to identify and classify property terms because 
     each of these property terms carries an inherent and often 
     extensive domain associated with it.  A subset of the property 
     term's inherent domain becomes part of a particular data element 
     domain.   To illustrate, consider the data element "color of 
     eyes."  The domain of this data element contains a subset of 
     "color's" domain (i.e., the part of the domain that pertains to 
     eye colors).   The classification of this special class of 
     concepts assists in delineating and standardizing relevant 
     property terms with their valid value sets for use in data 
     elements.  
     
     In addition to standardizing property terms for consistency of 
     use, ISO/IEC 11179, Part 2, introduces relevant information 
     concerning taxonomies and ontologies of context objects.
     
     Basic Attributes of Data Elements, the increased use of data 
     processing and electronic data interchange heavily relies on 
     accurate, reliable, controllable and verifiable data recorded in 
     databases.
     
     One of the prerequisites for a correct and proper use and 
     interpretation of data is that both users and owners of data have 
     a common understanding of the meaning and representation of the 
     data elements. To guarantee a shared view of data elements, a 
     number of attributes have to be defined.
     
     This Part 3 of ISO/IEC 11179 specifies attributes of data 
     elements. It is limited to a set of basic attributes independent 
     of their usage in application systems, databases, data 
     interchange messages etc. The basic attributes specified are 
     applicable for the following main activities:
     
     	  a)  definition and specification of the contents of data 
          element dictionaries;
     
     	  b)  design and specification of application-oriented data 
          models, databases and messages for data interchange;
     
     	  c)  actual use of data in communications and information 
          processing systems;
     
     	  d)  interchanging or referencing among various collections 

          of data elements.
     
     Basic means that they are essential in specifying a data element 
     completely enough to ensure that it will be applicable for a 
     variety of functions such as: 
     
     	       design of information processing systems; 
     	       retrieval of data from databases;
     	       design of EDI-messages for data interchange; 
     	       maintenance of data element dictionaries; 
     	       data administration; 
     	       dictionary design; 
     	       dictionary control; 
     	       use of information processing systems;
     
     Basic also implies that the attributes are independent of any:
     
     	       application environment; 
     	       function of a data element (e.g. qualifier, indicator);
     	       level of abstraction of the meaning (e.g. a 
               representation of a generic concept like 'name of a 
               person' or a representation of a specific concept like 
               'name of the driver of a truck'); 
     	       grouping of data elements;
     	       method for designing information processing systems or 
               data interchange messages;
      	       data element dictionary system.
     
     Basic does not imply that all attributes specified in this Part 
     of the International Standard are required in all cases. 
     Distinction is made between those basic attributes that are:
     
     	       mandatory: always required;
     	       conditional: required to be present under certain 
               specified conditions;
     	       optional: allowed but not required.
     
     The set of basic attributes can be extended with additional 
     attributes, e.g. to enable the performance of a comprehensive 
     data management function in an information management domain. 
     Examples thereof are given in an informative annex to Part 3. 
     
     Rules and Guidelines for the Formulation of Data Definitions, 
     Part 4 of ISO/IEC 11179-4, provides guidance on how to develop 
     good data element definitions.  A number of specific rules and 
     guidelines are presented in this document that specify exactly 
     how a data element definition should be formed.  A precise, well-
     formed definition is one of the most critical requirements for 
     shared understanding of a data element; well-formed definitions 
     are imperative for the exchange of information.  Only if every 

     user has a common and exact understanding of the data element, 
     can it be exchanged trouble-free.
     
     Naming Principles for Data Elements, Part 5 of ISO/IEC 11179, 
     provides guidance for the identification of data elements.  
     Identification is a broad term for designating, or identifying, a 
     particular data element.  Identification can be accomplished in 
     various ways, depending upon the use of the identifier.  
     Identification includes the assignment of numerical identifiers, 
     or Data Element Identifiers (DEID), that have no inherent meaning 
     to humans; icons (graphic symbols to which meaning has been 
     assigned); and names with embedded meaning, usually for human 
     understanding, that is associated with the data element's 
     definition and domain.   
     
     Names are semantic, natural language labels given to data 
     elements and variations of these labels serve different 
     functions.  Some names are for human usage and comprehension; 
     some names are for use in a particular physical system 
     environment.  Names are often user established and vary from one 
     user to the other.  The principles in this document describe the 
     various functions of names and how names are used.  
     
     Names must be clear, brief, rule-conformant, and free of physical 
     context.  They are formulated according to rules which are not 
     dependent on any specific natural language syntax.  They contain 
     no concepts which are not represented in the definition; they 
     ideally contain all concepts which are represented in the 
     definition.  
     
     Names contain certain components in their construction.  These 
     components are property terms, context terms, and modifiers.  In 
     some naming convention paradigms, property terms are known as 
     "class words" and context terms are known as "prime words".  
     Property terms are the common, unit, abstract nouns that identify 
     the category of data usage of the data element (e.g., "code", 
     "name").  Context terms are the concrete terms derived from the 
     application's context (e.g. "product", "aircraft"), and modifiers 
     are additional words used to specify or restrict the property 
     terms and context terms (e.g., "current", "military" ).  
     
     These three components of a name are consequential because they 
     indicate the data element's domain and context.  There is a very 
     close relationship between the name and the domain of a data 
     element.  
     
     Registration and Maintenance of Generic Data Elements, Part 6 of 
     ISO/IEC 11179, provides instruction on how to register a data 
     element with a central registration authority and the allocation 
     of unique identifiers for each data element.  Maintenance of data 

     elements already registered is also specified in this document.