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
patrick@xxxxxxxxxxx
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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