too much complexity?

[Tony Linde]

I think 'complexity' is in the eye of the beholder. Personally I don't mind
if the schema gets fairly complex from a developer's point of view if it
means that life is made easier for the *user*. 

The first schema associated with earlier versions of RM had metadata
relating to many types of resource all bundled into a single entity. This
was very confusing to the user as NVO found out in its trial. I also find it
confusing that we try to use terms from DC when we could just as easily use
terms familiar to astronomers. DC compliance can be implemented later
through back-end systems, it should have no impact whatever on the schema.

> (2) What is the list of metadata formats that the registry 
> covers? To me it is Services, Datasets, Projects, 
> Organizations. Why are "people" still in the registry? Can't 

If you look at
http://wiki.astrogrid.org/bin/view/Main/TonyOnRegistryStructure you'll see
that my own original approach was that community information should be
separate from services - it could all use the same base Resource, Authority
and Registry schema but the derived community schema would be defined and
stored separately. I don't see why organisations and projects should be in
the service registry and if they must be then adding people makes just as
much sense - *to me*.

> (3) What small committee is responsible for additions -- and 
> pruning -- in the light of experience? Let us form this in 
> Strasbourg. What is the best number of people? 6? 10?

Initially, me and Ray as requested by the IVOA meeting in Sydney. We already
have a larger committee in the Registry WG which, according to
http://www.ivoa.net/twiki/bin/view/IVOA/RegistryWorkingGroup has 9 members.
Whatever committee we form, it is then up to the community to comment on
documents which is what is happening now.

> (4) Why are there suddenly five kinds of linking 
> relationship? If simple "citation" is good enough for the 
> Journals, why is it not good enough for VO? Half the people 

Presumably because the VO does not deal with Journals. Do journals mirror
each other? Can you take one journal, analyse the contents and release it as
another journal? Let's identify the relationships between resources that
astronomers want to know about in forming a query.

> (5) If a Fortran programmer even older than me 

You talking about me?

> approaches the 
> registry to publish, or to query, can we make something 
> understandable for him/her? What does that form look like? 
> Our primary purpose is capturing that metadata, not pandering 
> to the most complex cases.

Right, let's focus on the user. In registering a resource, the user will
only want to provide metadata relevant to the resource and not have to sift
through metadata that is irrelevant, and will want to see it described in
terms that he/she is familiar with rather than have to interpret terms from
another field.

Does this sound reasonable as an approach?

Cheers,
Tony. 

> -----Original Message-----
> From: owner-registry at eso.org [mailto:owner-registry at eso.org] 
> On Behalf Of Roy Williams
> Sent: 16 September 2003 23:29
> To: registry at ivoa.net
> Subject: too much complexity?
> 
> 
> This registry schema is getting to be very complex. Even to 
> understand the simplest xml instance, there need to be 6 or 8 
> schemas ingested. When we make binding tools for VOResource, 
> there are hundreds of classes generated, one for each 
> element. The number of people in the world who fully 
> understand the details can be counted on the fingers of one 
> hand. I am reminded of a Bill going through Parliament, 
> having special interests adding their own pork-barrel 
> projects. The rule in NVO is not to attempt completeness, but 
> rather to get 95% of the use cases with 20% of the work. How 
> can we return to this maxim?
> 
> These are the burning questions for me:
> 
> (1) Is this schema modular? Do I need to parse all the 
> optional modules in order to work with the core? What is the 
> semantic nature of the core module?
> 
> (2) What is the list of metadata formats that the registry 
> covers? To me it is Services, Datasets, Projects, 
> Organizations. Why are "people" still in the registry? Can't 
> Astrogrid do their own thing somehow without bothering IVOA, 
> since they are the ones that want this? They can make a 
> "person" schema that includes VOResource, rather than forcing 
> VOResource to include "person".
> 
> (3) What small committee is responsible for additions -- and 
> pruning -- in the light of experience? Let us form this in 
> Strasbourg. What is the best number of people? 6? 10?
> 
> (4) Why are there suddenly five kinds of linking 
> relationship? If simple "citation" is good enough for the 
> Journals, why is it not good enough for VO? Half the people 
> filling in these forms will do nothing in response to a 
> complicated question -- and so we lose metadata -- but they 
> will recognize and respond to the word "citations".
> 
> (5) If a Fortran programmer even older than me approaches the 
> registry to publish, or to query, can we make something 
> understandable for him/her? What does that form look like? 
> Our primary purpose is capturing that metadata, not pandering 
> to the most complex cases.
> 
> (6) How many registry entries will there be for Vizier? If it 
> is only one, then I suspect few people will be interested in 
> the registry. If it is one for each of the 5,000 catalogs, 
> then how many fields in VOResource will be filled in for each?
> 
> (7) Am I the only one with these mutinous thoughts?
> 
> 
> --------
> Caltech Center for Advanced Computing Research 
> roy at cacr.caltech.edu 626 395 3670
>