Re: Creation/Modification times and Revision Numbers
Bryan Heidorn wrote:
What I am concerned about with the revision number is easing processing for www spiders and for composite documents created from lower level documents/treatments. www spiders search the network for new documents to index. If the documents are dynamically created "on demand", they are in some way different every time the spider looks, if nothing else because the "creation date" will change to always be now. We need something more stable like editorial date... the last time a qualified human said the record was OK.
Yes. Each "atomic element" must have a "date last modified [by authority]" attribute for the reason you suggest.
However, would not the spec also need to require that the "spider", or specifically those processing instructions that define the "behavior" or result set produced by the spider or other collation [transformation] programs (methods), also leave a distinguishing revision number in the document so that one can determine what specific method was used? One might expect different behaviors even for slight changes to the processing (compilation) code used to assemble the consitutent [atomic] elements of the document to influence the document content.
Even though there may be transient lack of availability of some distributed resources (perhaps due to network failure, loss of a particular server, server load, etc.] , the behavior of the "spider" also could influence the document content [atomic element inclusion], albeit independently. This would be an issue for "higher level" associations (documents) that are created by automatically assembling other "documents" that are themselves constructed from "atomic elements". Consequently, requiring the "spider" [read element inclusion processing instructions] to leave an identifying mark in the document would provide an ability to distinguish the source of the potential differences in the final dynamic document.
The same problem exists for higher level taxon descriptions that are created from lower level descriptions. There was a short thread about this a while ago on this list. A good feature of dynamic creation of the descriptions is that when a low level detail changes the higher level summary information also automatically changes. The "oops, that specimen was actually a different species" syndrome, may cause a character state recording some value to change (because the outlier was recognized as another species.) We do not want to have to recalculate and verify all atomic facts whenever someone looks at a high level description.
Yes, I fully agree that the lower [atomic] level of detail must force changes at higher more associative/inclusive levels precisely for the reason you suggest.
However, within an environment where the data may be distributed there may be sources of error that may be generated when "key" atomic elements are not found (server load to great, network failure, etc) or perhaps only older versions can be located (only mirrors available, unflushed cache, etc). Consequently, to assess the logic needed to [possibly further] process or interpret a document's contents would it not be useful to also have a means to pass knowledge of what methods were used to assemble the document? Presumably, the behaviors of the processing instructions (document generating methods) will influence the circumstances under which some kinds of atomic element processing instructions (methods) will fail while others may succeed, say in making subsequent changes "automatically" or "recognizing" the existence of another species.
Don't we need a spec that includes [requires?] a means to pass knowledge about the kinds of associations that were made to generate the document, as well as the lower level "atomic elements"and their attribution, if we are to avoid recalculation to fundamental atomic level at each stage in the transformation (document building) process? If documents were characterized in XML, this could make it much easier to chain XML transformations by faciliating the recognition of what order of transformations were permissible. This could also greatly simplify the modification of processor (method) behavior and the development/maintenance of efficient interprocess communication. A document that was validated by successfully being transformed at one lower level of processing to another by a given method, would not require revalidation at these "lower levels" when being transformed to the next "higher" level by another method. Presumably, such tags could be scattered at widely different levels within the document, indicating scope of the document over which specific transformations were relevant.
These issues are separate from the kinds of errors that may result when a method encounters "atomic elements" that are internally inconsistent, within a distributed processing environment. So far we've avoided how to handle this separate issue within the spec. I don't have an answer except perhaps simply requiring everyone to agree :-) or specifying the kinds of errors that should be generated under such conditions.
Perhaps others may suggest a better/alternate approach to address these aspects of dynamic document generation/transformation within the spec.
Wow, what a pile of trouble for a little feature!
I do not know what to do about defining "treatment", "document", "collection" and "project". I am willing to adopt any one else's definitions. The key point is that there are actually different things that need to be treated differently some how.
Thats fine by me as long as we can communicate which ones we're using.
Bryan At 04:16 PM 8/15/00 -0600, Stuart G. Poss wrote:
Bryan Heidorn wrote:
Yes, perhaps there are really two different fields Treatment creation time and revision number. I think time alone is not
enough
since one can not tell from that if the treatment has changed since it was last viewed or used (to create higher level treatments).
Do you instead mean time created and time last revised, as well as revision number?
It is conceivable that different systems (servers) might have various,
slighly
different versions of the constructional software running on them that could,
at
least in principle, produce two different version numbers even when "simultaneously" generating elements of the same document (treatment?).
Don't we need to keep in mind that both "collections [attributable to a
unique
source?]" and "treatments [virtual collections generated from multiple
sources
with respect to specific <processing> instructions?]" [or visa versa?]
may be
dynamic in distributed environments?
I too remain unsure how the concepts and scope of terms "treatment" and "document" and "collection" are being used (defined) as this discussion
emerges.
It might be useful for us to maintain a glossary, perhaps with qualifiers (ie sensu Bryan or sensu Kevin, etc), as such issues arise. We can then at least know whether we agree/disagree with respect to what definitions required or
with
respect to how the definitions are used.
| The current standard makes a relatively weak standard that the
contributor
| codes are unique to the treatment. I think we need to use a broader | definition. The should be unique to a collection at least.
Again we have a definitional problem and I think my treatment = your collection.
| Attribution: | Must this be a contributor? If so this information should be handles
as a
| property of <CONTRIBUTOR ROLE=PRINCIPAL|COPRINCIPAL> or as another
tag of
| <CONTRIBUTOR> | .... <ROLE>PRINCIPLE</ROLE>.... | Suggestions?
Yes, it could be done like this, but what would be wrong with doing it the other way - seems somehow neater to me, and I can't see much inefficiency.
It could
--
P. Bryan Heidorn Graduate School of Library and Information Science pheidorn@uiuc.edu University of Illinois at Urbana-Champaign (V)217/ 244-7792 501 East Daniel St., Champaign, IL 61820-6212 (F)217/ 244-3302 http://alexia.lis.uiuc.edu/~heidorn
--
P. Bryan Heidorn Graduate School of Library and Information Science pheidorn@uiuc.edu University of Illinois at Urbana-Champaign (V)217/ 244-7792 501 East Daniel St., Champaign, IL 61820-6212 (F)217/ 244-3302 http://alexia.lis.uiuc.edu/~heidorn
participants (1)
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Stuart G. Poss