[Crm-sig] Recording absence
martin at ics.forth.gr
Thu Dec 12 23:14:46 EET 2019
On 12/11/2019 7:13 PM, van Leusen, P.M. wrote:
> Dear Martin,
> the following has unfortunately languished in my 'drafts' folder for a
> while, but is hopefully still of interest:
> Re 'database thinking': in many cases the fact that nothing was
> collected is not being positively recorded - you have to infer it from
> the absence of finds data in the database. This seems very poor
> practice to me.
Indeed, I agree.
> In my own surveys I produce actual empty curated holdings, in the form
> of a ticket stating that a particular survey pass resulted in no finds
> (using the 'empty set' symbol). This is 'curated' in the sense that it
> goes into storage along with the finds bags that do contain finds.
This is, as I stated below, filling in slots. This slot implies
something, let me interpret:
A) someone has taken care to see something in a given area and time. The
bag is not empty because she was sleeping.
B) There are no flies in the bag, no grass, no plastic bottles.
C) She was using eye-sight. The traces we are looking for have a lower
limit in size, may be also an upper, when only aerial imaging would
D) She makes human errors, giving us some idea of what someone may miss.
> Re seeking but not finding: in an archaeological survey we are not
> seeking things that we know must be there, like a lost key; it's more
> like making a measurement: how many of several classes of objects (the
> 'things expected at the start of the investigation') do we encounter
> in a given piece of land? So finding '0' of anything is a valid
> result, but instead of recording zero finds for all possible finds
> categories, we just record no finds, period.
I'd argue, there is nothing like all possible finds categories. You
cannot survey without a hypothesis of things relevant, you cannot
observe anything without a model of the phenomena you observe.
This is why we use generalization. I assume you are looking for man-made
features and objects possibly older than XXX. That should be good
enough. If you are surveying pollen, you will use a different method.
The flies are for the entomologist's survey, the plastic bottles for the
environmentalist, the grass for the botanist. So, it's not anything.
I'd argue that this has to be modelled at the survey activity: kind of
thing, method used. Then you can define a property: "encountered things
of kind", and another "did not encounter things of kind": Man-Made-Object.
I think it is more bad practice not to state what has been sought.
From such a model, we can infer a lot of useful things. The empty bag,
we cannot distinguish from laziness;-)
> On Tue, Nov 5, 2019 at 6:03 PM Martin Doerr <martin at ics.forth.gr
> <mailto:martin at ics.forth.gr>> wrote:
> Dear Martijn, All,
> As you state, an empty collection does not really work, because
> nothing is curated or created. This would be "Relational Database"
> thinking, where you fill in slots.
> The interesting thing is, to be clear about WHAT is negated. What
> is a "no archaeological finds at all" ?
> Obviously, it needs a specification of WHAT was sought or expected
> starting the investigation. This appears to be E55 Types. So, we
> have a property "O19
> has found object of type (was type of object found by)", and its
> negative. This is not dramatic, to define for all respective
> properties the "categorical" equivalent, and the negative, once
> they are simple deductions, and do not proliferate.
> But interesting is also the activity of seeking, but not finding.
> So, a survey is seeking, results in n encounters. Here, we have
> "no encounter event", no event linking to "object of type". This
> is more complex. The "no" is about the event....
> On 11/5/2019 5:36 PM, van Leusen, P.M. wrote:
>> Dear Athanasios,
>> this same issue came up during discussion of the ontology of
>> archaeological field surveying, where we wish to (and in some
>> cases, have in fact) recorded the absence of surface finds from a
>> specific piece of investigated land. A typical situation would
>> be, that a survey team has 'walked' a field with a particular
>> observation intensity, say 20% (so 20% of the field's surface has
>> actually been inspected), and has made no archaeological finds at
>> all. This results in an 'empty' collection (0 finds), which is a
>> valid outcome just like 1, 10 or a 1000 finds would be. It was
>> suggested by George Bruseker to model such survey collections as
>> Curated Holdings, but that only works as long as there is
>> something physical to curate - so it does not work for 'empty'
>> So, what solutions might be possible, analogous to the options
>> that you've presented here? Either we allow Curated Holdings with
>> zero members, or we introduce negative properties.....
>> On Tue, Nov 5, 2019 at 4:03 PM Athanasios Velios
>> <thanasis at softicon.co.uk <mailto:thanasis at softicon.co.uk>> wrote:
>> Dear all,
>> Following the Linked Conservation Data workshop and the last
>> SIG in
>> Crete I am summarising the problem of documenting non-existence.
>> An example of non-existence is: a book cover (a particular)
>> tooled decoration (a type).
>> Options for encoding:
>> 1) As discussed here:
>> we could have a new E55 Type "books without decoration". This
>> is a good
>> solution but the problem is that we will need an unmanageable
>> number of
>> composite thesaurus terms to cover all possibilities, e.g.
>> without a feature, or types of events which did not happen etc.
>> 2) In past SIGs we have mentioned negative properties. This
>> is also a
>> good solution but not quite in scope. A negative property
>> particulars for domain and range. So I can say that:
>> cover(E22 Man-Made Object) → NOT P56 bears feature → tooled
>> decoration(E25 Man-Made Feature)
>> This would mean that the specific book does not carry the
>> decoration. But I want to say that the specific book does not
>> carry any
>> 3) So I pestered Carlo for a few days and he says:
>> "To express negative information in an ontology, it is
>> recommended to
>> use specific axioms. For example, to state that certain books
>> have no
>> decorations the axiom would require to create a special class
>> for those
>> books and to make that class a sub-class of the class expression
>> 'individuals with less than 1 decorations'. This will require
>> a class
>> and an axiom to be created for each type of negative
>> information to be
>> expressed. But it has the advantage of using a standard OWL 2 DL
>> inference engine to reason about that negative knowledge,
>> both for
>> maintaining consistency and for query answering."
>> So what Carlo thinks is that option 1 is reasonable and in
>> fact instead
>> of using simply a thesaurus, one should elevate these
>> definitions to
>> ontology classes and axioms.
>> I would be interested to hear views from the list, as I am
>> not sure how
>> to model such statements. Those of you who have looked at
>> this in the
>> past, do you get a sense of the scale for negation statements?
>> Thank you.
>> P.S. A parallel thought which did not capture Carlo's
>> imagination was a
>> "typed negative property", i.e. create new negative
>> properties with E55
>> as range as in:
>> cover(E22 Man-Made Object) → NOT P56 bears feature of type →
>> decoration(E55 Type)
>> but I am not sure how this would translate to logic in an
>> inference engine.
>> Crm-sig mailing list
>> Crm-sig at ics.forth.gr <mailto:Crm-sig at ics.forth.gr>
>> Dr. Martijn van Leusen
>> Associate professor, Landscape Archaeology, Groningen Institute
>> of Archaeology
>> Poststraat 6, 9712ER Groningen (Netherlands) / phone +31 50 3636717
>> Chair, Examination Board for Arts, Culture and Archaeology /
>> Chair, Faculty of Arts Advisory Board for Data Management policies
>> Academia page <https://rug.academia.edu/MartijnvanLeusen>
>> Crm-sig mailing list
>> Crm-sig at ics.forth.gr <mailto:Crm-sig at ics.forth.gr>
> Dr. Martin Doerr
> Honorary Head of the
> Center for Cultural Informatics
> Information Systems Laboratory
> Institute of Computer Science
> Foundation for Research and Technology - Hellas (FORTH)
> N.Plastira 100, Vassilika Vouton,
> GR70013 Heraklion,Crete,Greece
> Email:martin at ics.forth.gr <mailto:martin at ics.forth.gr>
> Crm-sig mailing list
> Crm-sig at ics.forth.gr <mailto:Crm-sig at ics.forth.gr>
> Dr. Martijn van Leusen
> Associate professor, Landscape Archaeology, Groningen Institute of
> Poststraat 6, 9712ER Groningen (Netherlands) / phone +31 50 3636717
> Chair, Examination Board for Arts, Culture and Archaeology / Chair,
> Faculty of Arts Advisory Board for Data Management policies
> Academia page <https://rug.academia.edu/MartijnvanLeusen>
Dr. Martin Doerr
Honorary Head of the
Center for Cultural Informatics
Information Systems Laboratory
Institute of Computer Science
Foundation for Research and Technology - Hellas (FORTH)
N.Plastira 100, Vassilika Vouton,
Email: martin at ics.forth.gr
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