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BIBFRAME  November 2014

BIBFRAME November 2014

Subject:

Closed and Open Assumptions was [BIBFRAME] [Topic] Types

From:

Karen Coyle <[log in to unmask]>

Reply-To:

Bibliographic Framework Transition Initiative Forum <[log in to unmask]>

Date:

Fri, 7 Nov 2014 08:09:21 -0800

Content-Type:

text/plain

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text/plain (273 lines)

On 11/7/14 4:55 AM, [log in to unmask] wrote:
>> Adding the rdf:type in instance data is convenient for data consumers, and that's fine; however note that it is a convenience, not a requirement.
> I disagree. It is in fact very much a requirement if you would like to avoid requiring inferencing regimes for Bibframe.

I'm getting a hint of closed-world assumption in some of this 
discussion. Most likely, the future library system software that 
hypothetically uses BIBFRAME or some other RDF ontology may use explicit 
typing to make those systems more efficient. And if we all contribute to 
some RDF/OCLC of the future, it may do the same. But in the open world 
of LOD that is just one giant graph, anyone can use BIBFRAME properties 
however they wish. (Anyone can say Anything about Anything). In that 
open world you cannot "require" anything beyond what you define in your 
ontology, which comes along not as constraints but as semantic baggage 
(hopefully useful baggage).

I'm fine with anticipating a bibliographic closed world since it seems 
likely to happen, for practical reasons. If that's what we're addressing 
here, though, we should be clear about it, and separate the closed-world 
discussion from the open-world one.  We should also then talk about 
whether that closed-world BIBFRAME that is being designed is also what 
will be opened to the LOD world, and how it will play in that world. My 
gut feeling is that use cases and requirements for that closed world 
could be quite different from those of the open world. So another set of 
use cases is: what do we anticipate today as uses for bibliographic data 
in the open world? I'd expect a lot of linking to diverse data, and 
trying to identify the same resource when it appears in different 
contexts (like connecting article citations to library holdings).

Since RDF/RDFS/OWL do not provide constraints, just open-world based 
inferences, something else is needed to meet the requirements of the 
closed world. This is the topic of a newly formed W3C group called 
"Shapes" [1] and a Dublin Core RDF validation group [2]. The existing 
technologies that address this are SPIN, ICV, and Resource Shapes. [2] 
BIBFRAME can work on its own closed world design, perhaps extending the 
BF Profiles, and feel fairly confident that the W3C work will meet our 
needs. If we think it won't we can contribute our own use cases to that 
process. The easiest way to do that is through the Dublin Core group,[4] 
which is then feeding a set of cultural heritage use cases to the W3C 
effort (since that group is heavily business based). [Note that the DC 
group invited participation and use case info from BIBFRAME but did not 
receive a response.]

I encourage anyone who can do so the sign up for the relevant mailing 
lists (they are open) and contribute to this work. The DC group has no 
limitations on who can participate (W3C requires institutional membership).

kc

[1] http://www.w3.org/2014/data-shapes/wiki/Main_Page
[2] http://wiki.dublincore.org/index.php/RDF-Application-Profiles
[3] http://www.w3.org/2012/12/rdf-val/submissions/Stardog (not a 
complete explanation, but covers all three)
[4] Dc group has a database of case studies, use cases, and requirements 
that is still being worked on:
http://lelystad.informatik.uni-mannheim.de/rdf-validation/
It also has a testing environment, also in progress, where you can try 
out difference scenarios:
http://purl.org/net/rdfval-demo


> Take two applications, one RDFS-inferencing and one not. Give each a set of triples, one explicitly typed and one not explicitly typed, but typed correctly under RDFS semantics. For the first set of triples, both applications will work correctly. For the second, only the inferencing application will work correctly. If you do not want to require inferencing in Bibframe applications, you must not assume on it.
>
>> Yet I do not have the impression that we are thinking beyond the creation of data that, if at all possible, doesn't disrupt our MARC21 past. In the IT design world, you usually begin with what functions you wish to perform (use cases, requirements) before determining the structure of your data.
> I couldn't agree more. Examining:
>
> http://bibframe.org/documentation/bibframe-usecases/
>
> I find 15 use cases, of which only 5 feature patrons as the user. The others feature one or more catalogers. Benefits to patrons from this effort might seem to be somewhat incidental to it.
>
> ---
> A. Soroka
> The University of Virginia Library
>
> On Nov 6, 2014, at 8:41 PM, Karen Coyle <[log in to unmask]> wrote:
>
>> Simeon, I do not feel that bf data should not have explicit typing. I simply do not see that as negating the typing provided by the RDFS function of domain. One does not override or invalidate the other. Adding the rdf:type in instance data is convenient for data consumers, and that's fine; however note that it is a convenience, not a requirement. Because we have multiple ways of providing typing, however, we have to be careful how the typing in the ontology and the typing in the instance data interact.
>>
>> If you do provide sub-class and sub-property relationships and domains and ranges, you cannot prevent others from using these for inferencing -- since that is the defined use for those declarations in your ontology as per the semantic web standards.
>>
>> All of these arguments, however, are empty without some real use cases. What is the use case behind the declaration of types? Do we anticipate particular searches that make use of them? If, as some feel, we should eschew inferencing, then what *is* the role of the type in our data, whether explicitly defined or inferred from the ontology? We talk about the technology as if it exists in some kind of virtual space. This is our data that we are talking about! What do we intend to do with it? What kind of searches (of the SPARQL kind) do we anticipate running over this data? How do we see our data interacting with data from other communities?
>>
>> This isn't a question to answer in a vacuum. Yet I do not have the impression that we are thinking beyond the creation of data that, if at all possible, doesn't disrupt our MARC21 past. In the IT design world, you usually begin with what functions you wish to perform (use cases, requirements) before determining the structure of your data. This has been the case for decades, so it shouldn't be a surprise today. Use cases would reveal things like:
>>
>> - what do we see as the workflow for data creation?
>> - how will we share data among libraries for copy cataloging?
>> - what uses do we anticipate for a Work (apart from an Instance)? and for an Instance?
>> - if a user does a search on "Mark Twain" as author, what will the system provide as a response? A Work? A combined Work/Instance? What would be optimal?
>> - reiterating Joyce Bell's comments on the editor, what role do types have in the cataloging function?
>> - what kinds of searches do we want to do over our data?
>> - how will our data interact with the many many millions of bibliographic descriptions on the web?
>> - if someone does do inferencing over our data, what kinds of results do we hope that they will obtain?
>> - ... ad infinitum...
>>
>> Without answers to these questions, I don't see how we can evaluate BIBFRAME as it exists today. If we don't know what needs it is responding to, how can we know if it meets any needs at all?
>>
>> This is system development 101, folks. I'm not asking anything out of the norm.
>>
>> kc
>>
>>
>> On 11/6/14 4:22 PM, Simeon Warner wrote:
>>> To me the key motivations for expressing types explicitly are to make the data easy and efficient to use. To be able to "get things of type X meeting condition Y" seems likely to be extremely common need. Why make the "things of type X" part harder than it need be? If I look through the set of use cases we came up with for the LD4L project [1], most of them have some component of "finding things of type X".
>>>
>>> It seems a fallacy to argue that, because some external data will require type inference to be used with bf data, the bf data should not have explicit typing.
>>>
>>> I think a less important but not insignificant secondary reason is that it makes the data and model easier to grok. Karen suggests this is an unhelpful crutch: "My impression is that the primary use of rdf:type is to make data creators feel like they've created a 'record structure' or graph based on the type." but I think the additional clarity of intent is useful (and such redundancy permits various sorts of checks). IMO, one of the costs/downsides of RDF is complexity/subtlety to understand (see discussions on this list to make that plain!) and so anything we can do to make this less of a problem with bf is good.
>>>
>>> 2 yen,
>>> Simeon
>>>
>>>
>>> [1] https://wiki.duraspace.org/display/ld4l/LD4L+Use+Cases
>>>
>>> On 11/7/14, 6:33 AM, Karen Coyle wrote:
>>>> On 11/6/14 12:12 PM, [log in to unmask] wrote:
>>>>>> bf:workTitle with domain=bf:Work
>>>>>>
>>>>>> makes these two statements equivalent, although in #2 you must first
>>>>>> infer the type of :X from the predicate "bf:workTitle":
>>>>>>
>>>>>> :X a bf:Work ;
>>>>>>    bf:worktitle [blah] .
>>>>>>
>>>>>> :X bf:workTitle [blah] .
>>>>>>
>>>>>> In both cases, the type of :X is bf:Work.
>>>>> This is predicated on the operation of an inference regime, presumably
>>>>> RDFS or stronger. It is not true under plain RDF entailment.
>>>>>
>>>>> It's important to notice that assumption when it comes into play. RDF
>>>>> processing does not normally make it, because it is expensive, the
>>>>> expense varying with the strength of inference regime. For a strong
>>>>> regime and for applications that require processing with strong
>>>>> guarantees about response time, the expense can be prohibitive. It is
>>>>> possible to make inference a requirement for Bibframe applications,
>>>>> but I agree with Rob Sanderson: that would be a mistake. It should be
>>>>> possible for a machine to process Bibframe without engaging such
>>>>> machinery, and I say that even though I believe very strongly that
>>>>> inference is the most important frontier for these technologies.
>>>>>
>>>>> ---
>>>>> A. Soroka
>>>>> The University of Virginia Library
>>>> I don't at disagree, although in other venues I am seeing use of
>>>> inferencing, at least experimentally. But if you *do* include domains
>>>> and ranges for the properties in your ontology, then they should not
>>>> return inconsistencies when presented to a reasoner if someone *does*
>>>> wish to employ inferencing. Having those defined in the ontology means
>>>> that you support inferencing for those who wish to use it. Otherwise,
>>>> why even include domains and ranges in your ontology?
>>>>
>>>> And note that BF uses rdfs and domains and ranges on some properties:
>>>>
>>>>    <rdf:Property rdf:about="http://bibframe.org/vocab/contentCategory">
>>>>      <rdfs:domain rdf:resource="http://bibframe.org/vocab/Work"/>
>>>>      <rdfs:label>Content type</rdfs:label>
>>>>      <rdfs:range rdf:resource="http://bibframe.org/vocab/Category"/>
>>>>      <rdfs:comment>Categorization reflecting the fundamental form of
>>>> communication in which the content is expressed and the human sense
>>>> through which it is intended to be perceived.</rdfs:comment>
>>>>    </rdf:Property>
>>>>
>>>> You can't prevent anyone from using reasoning on the data. You still
>>>> have to get it right.
>>>>
>>>> kc
>>>>
>>>>> On Nov 6, 2014, at 2:46 PM, Karen Coyle <[log in to unmask]> wrote:
>>>>>
>>>>>> On 11/6/14 8:00 AM, Simon Spero wrote:
>>>>>>> On Nov 6, 2014 10:10 AM, "Karen Coyle" <[log in to unmask]> wrote:
>>>>>>>
>>>>>>>> If the bf:workTitle were of type bf:Work instead of bf:Title, you
>>>>>>>> would get:
>>>>>>>>
>>>>>>>> <X> rdf:type bf:Work .
>>>>>>>> <X> bf:workTitle _:aa .
>>>>>>>> _:aa rdf:type bf:Work .
>>>>>>>> _:aa bf:titleValue "Here's my title" .
>>>>>>>> Does that clear it up?
>>>>>>> Ah- now I think I understand-when you are talking about a property
>>>>>>> being of a certain type, you are talking about the range of the
>>>>>>> property, not the type of the property itself (ie the thing named
>>>>>>> bf:workTitle. Did it clear up? :-)
>>>>>>>
>>>>>> No, actually, I'm talking about the domain of properties, not the
>>>>>> range. The domain of the property asserts "instance of class" on the
>>>>>> subject of the property relation. So
>>>>>>
>>>>>> bf:workTitle with domain=bf:Work
>>>>>>
>>>>>> makes these two statements equivalent, although in #2 you must first
>>>>>> infer the type of :X from the predicate "bf:workTitle":
>>>>>>
>>>>>> :X a bf:Work ;
>>>>>>    bf:worktitle [blah] .
>>>>>>
>>>>>> :X bf:workTitle [blah] .
>>>>>>
>>>>>> In both cases, the type of :X is bf:Work.
>>>>>>
>>>>>> For others, perhaps, note that an subject (":X" here) can be of more
>>>>>> than one type. So there's nothing wrong with saying:
>>>>>>
>>>>>> :X a bf:Work;
>>>>>>     a bf:mapType;
>>>>>>     a bf:digitalObject .
>>>>>>
>>>>>> if you want to do that. And those types could either be explicit ("a
>>>>>> bf:xxx") or inferred. The latter could take advantage of something like
>>>>>>
>>>>>> bf:coordinates domain=mapType
>>>>>> bf:digForm domain=digitalObject
>>>>>>
>>>>>> And an instance that goes like:
>>>>>>
>>>>>> :X a bf:Work;
>>>>>>     bf:coordinates "blah" ;
>>>>>>     bf:digForm <URI-for-PDF> .
>>>>>>
>>>>>> That's probably not how you'd do forms, but it's the example that
>>>>>> came to mind.
>>>>>>
>>>>>> What this does mean is that you have to be careful what domains you
>>>>>> define for your properties, because they add semantics to your
>>>>>> subjects. (The most visible way to test this, IMexperience, is by
>>>>>> defining classes as disjoint and then mixing properties from those
>>>>>> classes in a single graph. Reasoners come back with an "inconsistent"
>>>>>> conclusion, telling you your data doesn't match your ontology.)
>>>>>>
>>>>>> kc
>>>>>>
>>>>>>
>>>>>>
>>>>>>> If the range of workTitle is declared to Work, then the value of the
>>>>>>> property as well as the subject of the property would also be an
>>>>>>> instance of bf:Work.
>>>>>>>
>>>>>>> Is a goal to treat titles as Works in their own right, and to be
>>>>>>> able to have titleValue asserted directly on X?
>>>>>>>
>>>>>>> Is a goal to find triples that may be reachable from instances of
>>>>>>> Work? In that situation, SPARQL 1.1 sub queries or property paths
>>>>>>> may do some of the work.
>>>>>>>
>>>>>>> Outside of SPARQL, some approaches to serving linked data return
>>>>>>> closely related entities alongside the base object, trading off
>>>>>>> bandwidth for latency or server load. id.loc.gov does this quite a
>>>>>>> bit ;the work on linked data fragments looks to combine this with
>>>>>>> client side query processing.
>>>>>>>
>>>>>>> Simon
>>>>>>>
>>>>>> -- 
>>>>>> Karen Coyle
>>>>>>
>>>>>> [log in to unmask] http://kcoyle.net
>>>>>>
>>>>>> m: +1-510-435-8234
>>>>>> skype: kcoylenet/+1-510-984-3600
>>>>>>
>> -- 
>> Karen Coyle
>> [log in to unmask] http://kcoyle.net
>> m: +1-510-435-8234
>> skype: kcoylenet/+1-510-984-3600

-- 
Karen Coyle
[log in to unmask] http://kcoyle.net
m: +1-510-435-8234
skype: kcoylenet/+1-510-984-3600

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