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Re: [ontolog-forum] Relating and Reconciling Ontologies (legacy systems)

To: ontolog-forum@xxxxxxxxxxxxxxxx
From: Patrick Durusau <patrick@xxxxxxxxxxx>
Date: Sun, 24 Apr 2011 07:28:37 -0400
Message-id: <4DB40965.9030602@xxxxxxxxxxx>
David,    (01)

On 4/23/2011 6:14 PM, David Eddy wrote:
> Jack -
<snip>    (02)

>> A topic map values all world views
> I'm not sure I agree with how this is said.
>    (03)

+1!    (04)

Topic maps, like any other map, have boundaries, either by design or 
necessity.    (05)

Think about the London Tube map or a map of the New York subway system. 
Both are quite valuable for their intended purposes and despite being 
maps, you would not consult either one for Martian cartography.    (06)

A topic map is constructed by one or more authors with mappings that are 
of interest to them or thought to be useful for others.    (07)

> The world view of "a system" (an extremely slippery concept) is
> actually quite constrained.  I worked on a 3,000 year old banking
> application (Letters of Credit) that contains 808 distinct data
> elements and 387 unique terms.
> In the context of a/many legacy systems what I want is the ability to
> easily find what's in Silo A (likely on a VERY narrow view).
> That is... I want the ability to ask for "policy number" which I can
> guess at&  be shown that since I'm in Silo A, one of the significant
> technical names is M0101.
Certainly it is the case now with software such as Talend and others, to 
create what I would call *blind* mappings that are point to point 
mappings between terms. That is there might exist a mapping between 
"policy number" and "M0101."    (08)

But that is hardly useful unless you know one of those two terms. And 
should you want to extend that mapping, to say silo X, you really have 
no way to know why the mapping was done in the first place. It could be 
that it was what we are assuming, a mapping of policy number, but it 
could also be the mapping of a primary ID. Or some other mapping. Hard 
to say without more information.    (09)

A topic map mapping can do more than simply point from one string to 
another, it can also include *disclosure* of what properties at both 
ends of the mapping must match in order for the mapping to occur.    (010)

And each of those properties are also subjects which can have properties 
and so be identified in various ways.    (011)

None of which is a magic talisman nor foolproof. But the disclosure of 
why a mapping was made offers the chance, albeit never a certain one, 
that you as a human reader will recognize a subject across a semantic 
gap and realize that is the same subject you are looking for.    (012)

Think of the days when we all used the Reader's Guide to Periodical 
Literature and for every entry in the index, we simply trusted there 
were some properties that resulted in that entry being made.    (013)

Topic maps offer the capability when we get to that entry to see what 
properties were seen as meriting that entry. We may or may not agree 
with it but we have a different (note I did not say better) opportunity 
to create more mappings based upon that information.    (014)

If you think of topic maps as offering the capability to capture the 
basis for the mappings between systems that we do anyway, that comes 
closest to being a shorthand view of them.    (015)

> Then if I say I also want to peer into Silo B, magically MSTR-POL-NO
> is what I'm needing to know.  Silo C... contract_id does the trick.
> In extreme circumstances, repeat 67 times (this might be something of
> a UI challenge.)
The challenge isn't a UI one but of discovery of those relationships and 
mapping them with properties to show why.    (016)

There is no magic bullet that will substitute for some process of 
determining that M0101 (Silo A) and MSTR-POL-NO (Silo B) and contract_id 
(Silo C) all represent the same subject and to provide a basis for 
mapping between them.    (017)

However, once that discovery is made, whether by you, a data analyst, an 
intelligence officer, a topic map can capture that as organizational 
memory and so the next person who comes looking, has an easier time of it.    (018)

Noting that you only need view as much or as little of the mapping(s) as 
is needful.    (019)

The real goal isn't 10,000 "hits" including blogs, tweets, webpages, 
ads, etc.    (020)

It is to have one (1) "hit" with the correct answer (for some particular 
circumstance, ....all the usual qualifiers).
> To date I have neither seen, nor heard ANY interest in this seemingly
> mundane task from the world of ontologies.  John Sowa excepted.
>    (021)

Well, I hate to defend ontologies, ;-), but you can think of ontologies 
as being one slice of a topic map pie that represents a particular world 
view and relationships within that world view.    (022)

Nothing wrong with that and for some purposes, like relational 
databases, can be quite effective at particular tasks.    (023)

It depends upon what you want to do.    (024)

If you are trying to map across information systems in ways that allows 
for merger of information from different information systems, where 
conversion would result in information loss, then you most likely need a 
topic map.    (025)

If you want to preserve your information domain as "your" domain for 
which you are the gatekeeper, then conversion using some basis known 
only to you is your best bet. (or that works with "your" software)    (026)

Ontologies, save you the time of creating your own map of some domain, 
but at the expense of using its view of a domain. Which may or may not 
be a close enough fit of your view to be useful. But there is no denying 
they have been useful in a number of contexts. My only reservation is 
the notion that any of them represent some sort of "truth" rather than a 
"view" of a domain. If the latter, then we should be able to have 
different "views" of the same domain, mapped to each other.    (027)

Hope you are having a great weekend!    (028)

Patrick    (029)

PS: In a shortened form: There are no universal maps just as there are 
no universal ontologies. There are maps and ontologies that are useful 
for particular purposes, times and circumstances. The more that is 
disclosed as the basis for any mapping, whether of ontologies or no, the 
easier its discovery and reuse by others.    (030)

Patrick Durusau
Chair, V1 - US TAG to JTC 1/SC 34
Convener, JTC 1/SC 34/WG 3 (Topic Maps)
Editor, OpenDocument Format TC (OASIS), Project Editor ISO/IEC 26300
Co-Editor, ISO/IEC 13250-1, 13250-5 (Topic Maps)    (031)

Another Word For It (blog): http://tm.durusau.net
Homepage: http://www.durusau.net
Twitter: patrickDurusau    (032)

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