Dear Martijn,
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
reveal it.
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;-)
Comments?
Best,
Martin
Martijn
On Tue, Nov 5, 2019 at 6:03 PM Martin Doerr <[email protected]
<mailto:[email protected]>> 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
<#m_-6633394639677410782_m_8077312891696986019__O19_has_found>*
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....
Comments?
martin
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'
collections.
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.....
Martijn
On Tue, Nov 5, 2019 at 4:03 PM Athanasios Velios
<[email protected] <mailto:[email protected]>> 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)
without
tooled decoration (a type).
Options for encoding:
1) As discussed here:
http://lists.ics.forth.gr/pipermail/crm-sig/2012-November/001873.html
,
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.
things
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
requires
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
specific
decoration. But I want to say that the specific book does not
carry any
decoration.
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.
Thanasis
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 →
tooled
decoration(E55 Type)
but I am not sure how this would translate to logic in an
inference engine.
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--
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>
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------------------------------------
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
Vox:+30(2810)391625
Email:[email protected] <mailto:[email protected]>
Web-site:http://www.ics.forth.gr/isl
_______________________________________________
Crm-sig mailing list
[email protected] <mailto:[email protected]>
http://lists.ics.forth.gr/mailman/listinfo/crm-sig
--
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>
--
------------------------------------
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
Vox:+30(2810)391625
Email: [email protected]
Web-site: http://www.ics.forth.gr/isl
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