Identification model in VO Spectrum Model

[Alberto Micol]

Doug,

As you say, let's go pragmatic, and let us first identify how many
and which contexts we have in mind.

In my own view, a context is somehow different than a use-case as you  
define;
data discovery and/or data analysis are use-cases and not contexts.
My first two candidate contexts are:
observed data as opposed to theoretical data.
For each of those one might want to specify different metadata,
and each context will need to support both use-cases
(data discovery and data analysis).

For the sake of a joke, what you call "overly complicating the  
specification", I would actually call "clarifying the contexts",
with the purpose of simplifying work at both data provider's and  
client developer's ends.

Good night!

Alberto


On Oct 25, 2006, at 23:05, Doug Tody wrote:

> Hi Alberto -
>
> On Wed, 25 Oct 2006, Alberto Micol wrote:
>> Wouldn't, hence, be possible to specify (in the protocol/DM)
>> the  different available contexts (adding for example an enumerated
>> CONTEXT attribute), and to define for each of them the proper
>> mandatory/optional/whatever fields?
>>
>> With that, clients will be able to specialise on a given context
>> based on solid grounds, and I find this possibility extremely  
>> valuable.
>>
>> Someone could argue that we cannot imagine all the possible usages
>> of a DM a priori; true! but on the other hand, as soon as someone  
>> comes
>> up with a new context, it will be not difficult to include it in the
>> next release.
>
> Frankly, I think it is pointless to try to specify in a general data
> model what is required/optional (except maybe for direct data analysis
> upon a dataset instance)); this needs to be done for each specific
> application of the data model.  The SSA protocol is one such case,
> although even here there are additional contexts for different  
> types of
> data or services.  It is difficult to deal with all of these without
> overly complicating the specification, however we have tried to do
> so by defining protocol-wide requirements with additional written
> narrative mentioning the special cases or contexts.
>
> It would be good to move this discussion to a more concrete level;
> I suggest reviewing the protocol document and commenting on what is
> required for a minimally or fully compliant service for the specific
> use-case of data discovery and selection.  (Followups on this specific
> topic should go to the DAL list).
>
> 	- Doug
>