Re: [xml-dev] 'is-a' Relationships in XML?

[Jonas Mellin <jonas.mellin@his.se>]

stephengreenubl@gmail.com skrev 2010-05-04 01:32:
> But clearly the markup can need more explanation via semantic definitions or specifications than would be needed by straight prose statements. E.g. I can lie by stating that I own Buckingham Palace. That implies Stephen D Green owns Buckingham Palace and this is not true. If I write markup<place name='Buckingham Palace'><owner>Stephen D Green</owner>then it depends what 'owner' means as to the truth and meaning of the markup. It could be the same lie as above or it could be the start of a document about a place where I was owner of the document, not owner of the place. So yes I accept to some extent what folk here are saying but with some reservation, as I think would anyone since we always leave some understanding of the semantics to the markup itself and don't express all of it in the spec and related defining artefacts.
We leave only data that can be interpreted as meaning given a model of 
interpretation. This model of interpretation is often implicit, tacit 
and opaque unless we use appropriate techniques to make it explicit, 
articulated and transparent (which is favored in, for example, research, 
engineering etc.). Explicit, articulated and transparent models of 
interpretation can be used for automated reasoning and decision making. 
One problem is that our model of interpretation is individual and, thus, 
the meaning may be wildly different for different people depending on 
their background. Two concrete examples of communication from real life:
1) I spent three days in another country with a research group that, 
according to our information sources, were within the same research 
field. However, it took about two days to start using concepts the same 
way, agreeing to the meaning etc.
2) There is a professor in Lund who maintains a slide of X-abilities 
(e.g., dependability, availability, flexibility) that he has collected 
from various researchers, engineers etc. and some people use the same 
concept for two different meaning and there are, of course, synonyms. 
Consider the difference between, for example, "data" and "information".
You may state that a sufficiently homogenous group of individuals will 
have a similar interpretation of data, but there may be minute 
difference that goes undetected. When we strive to achieve explicit, 
articulated and transparent models of interpretation, then our 
individual models of interpretation will become more closely related. 
However, there will be differences in these models. Further, as time 
goes by, our language change and so does the meaning. For example, using 
"scallywagging" and "gallyvanting" is archaic today.

So, I would like to rephrase it as "we leave data that in some model of 
intepretation convey meaning (semantics)".

/Jonas Mellin

> Plus we tend to let the schema express some semantics, as I was advised in early responses here, without perhaps restating all such semantics in a spec. We understand though the dangers and risks and address the clearest risks by making some semantics like calculation models explicit in a spec, perhaps even using formal logical english or a calculus. Or we create other artefacts specialised for expressing semantics like topic maps or ontologies and take it, in doing so, that the markup and maybe XSD do not adequately cover semantics but rather are optimised to express structure and constraints on structure. That makes sense.
> Thanks
> Steve
> Stephen D Green
>    
>
> -----Original Message-----
> From: stephengreenubl@gmail.com; stephengreenubl@gmail.com
> Sent:  03/05/2010 11:49:25 pm
> To: Michael Kay
> Cc: 'xml-dev'
> Subject:  RE: [xml-dev] 'is-a' Relationships in XML?
>
>
>
>
> -----Original Message----
> From: Michael Kay
> Sent:  03/05/2010 11:35:35 pm
> To: stephengreenubl@gmail.com
> Cc: 'xml-dev'
> Subject:  RE: [xml-dev] 'is-a' Relationships in XML?
>
>    
>> So making an 'employee' element  a child of an 'employer'
>> element clearly implies some semantics that the employer
>> 'has' the employees.
>>      
> And if 'employer' is a child of 'employee' then I suppose that the employee
> "has" the employer. But I don't think there's any semantics here: you're
> just using "has" as a synonym for "is the parent node of".
>
>
> -sdg:
> Not really. I think I'd be understanding that the markup was using the parent/child to represent the reality of the 'has' relationship. I accept that it's implicit to some extent but even the names of the elememts could be said to imply something about the reality being represented. Just as words represent reality, to some extent implicitly.
>
>
>
> If XML is well designed, then you can make guesses about the meaning of the
> data from the choice of element names and their hierarchic relationships.
> But XML is often badly designed, and your guesses in such cases will be
> wrong.
>
> Regards,
>
> Michael Kay
> http://www.saxonica.com/
> http://twitter.com/michaelhkay
>
>
>
>
>
>
>
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