Confused

[Reagan Moore]

I would like to add the definitions we are using for these terms in 
the development of knowledge management systems at SDSC:

- data consists of bits (zeros and ones)
- information is a semantic tag that is applied to data (typically a 
name that we assign to selected bits).  We use XML syntax to annotate 
data.
- metadata is the combination of the semantic tag and the associated 
bits (we typically store metadata in a database)
- knowledge is a relationship that is defined on the semantic tags. 
Examples are semantic/logical relationships ("isa" and "hasa"), 
structural/spatial relationships, procedural/temporal relationships.
- a data model is a structural relationship that is applied to data. 
Note that the structural relationships can be manipulated by methods. 
Methods in turn are procedural relationships that can be applied to 
the named structural components of the data model.
- ontologies are structural relationships imposed on semantic labels. 
Usually, the choice of semantic terms, and the choice of 
relationships between the terms are combined in the ontology.  Most 
ontologies focus on semantic/logical relationships.  The result is a 
concept space or a domain map.  When we organize semantic terms using 
procedural relationships, we create a process map that can be used to 
describe workflow systems.  When we organize semantic terms using 
spatial relationships, we create an atlas that can be manipulated by 
a GIS system.

Reagan Moore


>I've seen comments saying that we should use metadata instead of
>ontologies, data models instead of ontologies, data models instead of
>metadata etc.
>
>So what is the difference? And what do people mean by these terms?
>
>For myself:
>
>Data is information stored electronically.
>Metadata is data which describes some other data.
>Dataset is a collection of data organised by some principle.
>Data model is an ERM of a dataset which describes its underlying
>construction.
>
>Ontology is all of the terms and semantic relationships used in some
>domain discourse (which may be discovered and stored digitally but not
>necessarily).
>
>How about you?
>
>Cheers,
>Tony.
>
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>Tony Linde                       Phone:  +44 (0)116 223 1292
>AstroGrid Project Manager        Fax:    +44 (0)116 252 3311
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>University of Leicester          Email:  ael at star.le.ac.uk
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>