[Frederik Baumgardt]

Hi Tobias and Bridget,
Yes, the fact that we’re accepting arrays is a bit low-key in the Swagger UI — just a set of square brackets around the CollectionObject. We could add a description in the Implementation Notes, yay or nay?
Best,
Frederik

[Frederik Baumgardt]

Hi Uwe,
It’s in an hour! 14:00 UTC = 16:00 EST
Frederik

[Frederik Baumgardt]

Thank you, Juha — I have already begun to map between the WG’s terminology and e.g. dcterms during the process of implementing the RDF/LDP data store. My plan was to push this upstream into our definitions once it’s settled and looks sensible.
Best,
Frederik

[Frederik Baumgardt]

Thank you, Thomas! Adding two more bullet points:
– We figured out that maxDepth is actually relevant to both Service and Collection:
– In a service it describes constraints on the traversal operations
– A default here might be 0 => no server-side traversal
– In a collection it describes constraints on the data structure
– A default value here might be -1 => no limits on recursiveness
– In discussing the ‘role’ mapping there were different opinions about its generality and complexity:
– we may want to leave out the default value
– thus role becomes a simple and general tagging mechanism
– implementation requirements would be similar to index/dateAdded
– things like default values and controlled vocabulary would be left to the client
Next meeting is February 14th. See you there,
Frederik
—
Frederik Baumgardt
Data & Software Engineer
Perseids Project, Dept. of Classics
Tufts University

[Frederik Baumgardt]

A markdown version of the above list is posted here for collaborative editing: https://github.com/RDACollectionsWG/apidocs/wiki/Collections-and-Service…

[Frederik Baumgardt]

Hi,

I attached a current list of proprty fields. I started out with Bridgets Swagger definitions, the fields in italic are additions from my side.

Frederik

[Frederik Baumgardt]

Hi all,
we’ll meet in 15 minutes at the 997-874-677 Goto-Meeting.
In lieu of an official agenda, I’d suggest we discuss
1. Updates on the collection models that people have made
1.a. Tobias uploaded a v03 into DataShare
1.b. I have also uploaded a diagram about mapping to the PID record model
2. Ulrich’s formalization of Tobias’ definition
3. Anything else that you bring up
See you in a bit,
Frederik

[Frederik Baumgardt]

Tobias had shared his notes with me, so I’ll add the one point that wasn’t covered by Bridget:
Persistence and consistency:
– dependent on the final model for persistency, there will probably be combinations of persistency attributes at different levels that are inconsistent
– e.g. it might not make sense for a persistent collection to entail a non-persistent collection
– rules and/or supporting metadata might be part of the Capabilities model
Thanks to everyone in the meeting for a productive discussion, and Tobias and Bridget for taking notes!
Frederik

[Frederik Baumgardt]

Hi group,
thank you, Tobias – this looks like a good start!
To give input to some points made in the discussion below.
1) I agree that persistence is realized on different levels, and identifier, collection and object are the ones I came up with as well.
2) From 1) follows that extendable and shrinkable are mutability on the collection level. “Updatable” would be a term that describes mutability in the objects themselves.
2a) What about reordering an ordered collection?
3) I’d say that we have to keep the source collection in mind as well: pers. rule + pers. source = pers. resulting collection
3a) Generally, I’d think in terms of per reference and per value here. Meaning that the result of the rule is either dynamic or frozen.
X) I might have been unclear here – persistence is certainly not an attribute of collections in general. But in order to manage citability, we’ll have to provide it, I think. My thinking is thus that any changes to something that’s been dubbed persistent create a new version, and each individual version remains persistent to allow for citabillty.
Best,
Frederik

[Frederik Baumgardt]

@Tobias: Do the diagrams I put up on the Wiki reflect your mental models? I wouldn’t expect it, so feel free to replace them or scribble on them. I’d also save some of this discussion there, but I’m not yet sure I have full grasp of everybody’s conceptions.
@Bridget: It’s my understanding that the history pointer in your example does not meet the criteria of a PID as in, its content is mutable. Similarly the ‘latest’ pointer in a versioning system, or ‘HEAD’ in git. Whereas the commit IDs would.
I have this vague idea that we can interface persistent and mutable data spaces with persistent traits, e.g. a typed PID on a typed object requires that certain properties are immutable, but others which are not part of the persistent data type can be mutable. Citing a PID-referenced datum is citing the immutable properties only. E.g. a person has a stable SSN and DOB, but their name and address could change. The person’s PID would reference the SSN and DOB, but not the name and address. You can access those dynamically once you’ve got access to the properties of the persistent trait. Does that make sense? I do think it’s outside the scope of the WG though? Have other WGs addressed this issue?
Best,
Frederik

[Frederik Baumgardt]

Yes to Tobias’ question. And I think it might end up as provenance data, Thomas. The issue here being the definition of PID.
In the models that I’m familiar with, PIDs can only reference immutable objects and a stream would really be a set of relations between a series of static PID-referenced collections, e.g. realized as ‘parent’-properties.
However, I wonder how the PID model for e.g. OrcID deals with the mutability of the personal information it references. I.e. does it solve the issue with some sort of indirection or are there two different concepts of identity at work here; semantic and structural, where semantic identity is preserved over structural changes and structural identity is not. In which case semantic identity would actually be an indirection and I would be curious how that’s implemented (some constant properties in the referenced object?). And how it affects citability.
Sorry if my lack of familiarity with the previous work shows here, I’m actually working through a couple different PID specs at the moment.

[Author]

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