[sc34wg3] Review of N0393

Jan Algermissen sc34wg3@isotopicmaps.org
Sat, 26 Apr 2003 21:14:19 +0200

Lars Marius Garshol wrote:

<snip />
> Now, as to why the thing is not implementable, and why it is not a
> technology, I will just scratch a little in the surface of it. There
> are many many more problems with the document than those I point to
> below, 

Well, in order to advance N0393 it would be usefull if you would
list as many problems as you see. Sure we will try fix the 'many
more problems' once you point them out.

<snip />

> Some initial points:
>  - N0393 describes a particular model, but does not make it clear
>    whether, or how, that model enables any form of interoperability.

I don't understand exactly what answer you expect here. Let me try to
understand you:

What is the meaning of interoperability or what does it mean to enable

How does N0396 achieve interoperability?

>    Section 6 defines constraints on "Topic Map Applications", but it
>    is not clear what these are. N0393 says they are not software, but
>    are they documents? Are they file(s) in some defined syntax? Are
>    they merely abstract concepts?

My view of this is that ISO13250 should eventually include a DTD for
defining TMAs. This would make it possible for topic map documents
to include a reference to the TMA that governs them.

>  - It is not clear that the notion of the conformance of a Syntax
>    Deserialization Definition is useful. What does it mean for an SDD
>    to conform to this document? What value does it add for SDDs to
>    conform? 

Suppose SDDs would be defined in an XML syntax (propably looking close
to XSLT) then generic syntax processors could be implemented that would
be driven by SDD documents. In fact, syntax processors could fetch SDDs
from registries over the Web based on the document type they are to process
(e.g. XTM, NewsML, NITF etc.).

Is that a benefit?

>     What is to be done about SDDs that do not conform?

You mean: N0393 does not say whether or not to report an error?

You are right then, N0393 should say to report an error.

>  - In general, the conformance requirements of N0393 are very weak in
>    the sense that they are for the most part subjective judgments
>    formed by a human being, rather than something that is verifiable
>    by software. It is not clear that this is appropriate.

I'd have to go through the prose again and see if it is really that bad,
but this issue certainly doesn't affect the quality of the overall model.

>  - N0393 defines an information modelling formalism consisting of
>    topics, properties, and assertions, and then goes on to define a
>    model in terms of those primitives. However, the underlying
>    formalism is insufficiently defined, 

Why is it insufficiently defined? In fact, exactly this I think is very
clearly defined. What is missing from your POV?

[Suppose for a minute you were to implement N0393, what information is

> and the model built with it
>    appears to be far more complex than it has any useful need to be.

See my question on the differences between N0396 and N0393. What of
N0393 is any more complex than it needs to be.

In fact, I don't think you can get less complex than N0393.

In my own words:
"A topic map consists of topics that surrogate subjects. Properties on
the topics are used to define what particular subject a given topic

<snip />

> --- Introduction
> It is claimed that N0393 "enables Topic Map Applications to be
> expressed as topic maps", yet no vocabulary is defined for expressing
> the components of a TMA as an instance of the N0393 model. How does
> one express the "TM Application Name" in terms of N0393? The same
> applies to the other parts of the model.
> It is claimed that N0393 "enables the conformance of Topic Map
> Applications to this International Standard [sic] to be verified", yet
> it does not say *how* such verification is done. It would seem that
> verification is done by reading a TMA definition document manually and
> comparing it against the guidelines in N0393.
> It is claimed that N0393 "enables determination of whether two topic
> maps are identical". Where is the definition of the procedure that is
> used to do this determination?

Ok, I see what you mean. It is good to have feedback like this. In my head
it is so absolutely clear that I can't look at the prose and decide what is
missing anymore.

I am not sure now how far I agree with you, but I'll try to reread N0393 with
your eyes.

> --- Glossary
> As noted above there are several conflicts with the terminology of the
> SAM. These should be worked out.
> The concept of "treated as a set" is baffling. Why not just say "a
> set"? Why require a particular ordering? And is that indeed what the
> sentence "Apply the same comprehensively deterministic
> order-normalization algorithm to both lists" is intended to convey?
> The first paragraph of the definition is also quite surprising:
>   "Regarded (as a list) in such a way as to ignore both the order of
>   the items in the list, and any duplicates that appear in the list."
> The subject is missing from this sentence, and to "regard a list as a
> list in such a way as to ignore the order of the list" (paraphrase) is
> a very strange thing to do.
> I believe this whole concept is deeply flawed and that it should be
> replaced by the standard concept of a set.

Noted. Thanks.

> --- Subjects, topics, and properties
> In general, this section is severely underspecified, and a number of
> the design choices here seem suboptimal. Since this is the core of the
> whole model it is clear that N0393 is a castle built on sand.

So, does that imply that once the 'underspecification' you mention is
fixed and thus the sand turned into a solid rock, do we then have
a TMM that is an impregnable fortress, built for eternity?

Thanks for the details that follow, this is a helpfull review!


Jan Algermissen                           http://www.topicmapping.com
Consultant & Programmer	                  http://www.gooseworks.org