[seek-kr-sms] OBOE discussion: Ferdinand's version

Serguei Krivov Serguei.Krivov at uvm.edu
Wed Jul 26 11:20:45 PDT 2006


Shawn, 

It would be nice to give Ferdinando a chance to defend his version against
our criticism (after tomorrow morning hi will be unavailable for comments).

We were discussing the question "can a measurement be considered as a kind
of observation", where I do agree with Ferdinando and you don't. For
convenience I paste my last unanswered message below. In that message I
missed an important argument of yours that "sometime we can talk about
measurement even without mentioning any related observation". If this is
your argument, then it is argument against the current version of OBOE,
rather then against Ferdinand's version. In the current version every
measurement is connected to exactly one observation via the property
isMeasuredCharacteristicOf and therefore the situation you mention is not
allowed to exist  (should we  set cardinality  [0,1] for properties
hasSubject and isMeasurableCharacteristicOf, we may cover the case you
mentioned). In Ferdinand's version Observation is defined as a general
category and calling a measurement "observation" is a matter of naming
convention which is a bit different from the convention you use when you
assert that "we can talk about measurement without mentioning related
observation". Within Ferdinand's ontology it is  your assertion, which is
invalid- just by definition. I do not see any inconsistencies between this
definition and acceptable usage of the two words in English. Setting
cardinality [0,1] on property hasSubject ( of Observation) will allow to
talk about the measurements that have no subject- the situation of which you
were concerned.  What else?

 

As I mentioned,  I believe that Entities and Traits/Characteristic should be
reintroduced to Ferdinand's version and what currently is Observable should
become Characteristic. (I do not understand how entity per se could be
observable, but this is the question for the current version)

 

I think that the idea of CompoundObservation and AtomicObservation provides
much more natural better mechanism  for characterizing relation between the
columns of the table than what we have in the current version . ( I do not
ask anymore about characterizing relation between the rows. Let spatial and
temporal context do this job as many of you agree)

 

I also like the idea of ObservationSpace. This neatly generalizes numeric
measurements and qualitative observation, such as color of something, state
of health etc. The problem of correct description of numeric measurement
versus nominal observations  was surfaced in the messages of Matt, Bob
Morris and Jessy.  I think that the current version of OBOE has much bias
towards numeric measurement, while Ferdinand's version has a reasonable
generic framework to deal with both.

 

Most likely you disagree with most of these points. If you could explain in
some details why you disagree (when it is the case) before tomorrow , then
perhaps Ferdinando will have chance to reply on your critics. 

 

Cheers,

Sergey

 

 

 

 

----------------------------------

Sergey  Krivov, Research Assist.  Professor,

Computer Science Dept. & Gund Inst. for Ecological Economics, 

University of Vermont; 617 Main St. Burlington VT 05405

phone: (802) 656 0380

  _____  

From: seek-kr-sms-bounces at ecoinformatics.org
[mailto:seek-kr-sms-bounces at ecoinformatics.org] On Behalf Of Serguei Krivov
Sent: Thursday, June 22, 2006 3:58 PM
To: 'Shawn Bowers'
Cc: seek-kr-sms at ecoinformatics.org
Subject: Re: [seek-kr-sms] OBOE discussion: current version

 

> I am a bit confused here -- and maybe Josh, you can clarify.  My

> impression is that OBOE isn't currently changing in this way.  

 

Shawn,

One of the problem discussed yesterday was how to capture both normal
measurements and nominal ones. Obviously the current version of OBOE has
bias towards normal measurements and it is not clear if it would deal
satisfactory with the nominal measures, that is -classifications. The
majority who wrote on the subject consider those qualitative observation as
important and worth of our attention. Josh was trying to sum up the
yesterday discussion in one way and I thought that the summary he made is
worth of discussing.   I failed to underscore the word "proposed" while
talking about Josh's summary. I apologize.

 

> > So we have to remove attributes (roles, properties) measurement(0:n),

> > count(0,n) classification (0,1) from Observation. Alternatively, we may

> > refuse the idea of having Observation as superclass of Classification,

> Count

> > and Measurement.

> 

> I wouldn't say "refuse" the idea -- I would say that modeling measurement

> (and its various types) as observations has some problems --

 

So far I do not see what those problems are (besides those that I have
mentioned myself).

 

I think the reason to

> distinguish measurement and observation is because they are actually

> different things.  In the general setting, one can have observations

> independently of measurements, and measurements independently of

> observation -- suggesting these are fundamently different entities.

 

I wish we were living in a Plato's world , where concepts have real
existence. In such world all ontologies would exist in the same manner as
physical object exist and our job would be just to record them on paper the
way we do it with biomass, color etc. I think that Scholastics did believe
in this nice reality, but positivists came   and spoiled everything...

 

I think there is nothing that makes observation and measurement
fundamentally different, at least in this world. For a moment I thought that
may be I am the only one who think so. Then I typed in Google " define:
measurement" and I see many definitions; and some of them at the
middle/bottom of the page look as:

 

--An observation that reduces the amount of uncertainty about the value of a
quantity. In the balanced scorecard, measurements are collected for
feedback....

 

-- A logical rule for assigning numbers to observations to represent the
quantity of a trait of characteristic possessed

 

So, there are other people who confuse observation and measurement in some
way. But still, it would be nice we all  vote on the question:

 

Is it linguistically correct to consider  Measurement  as a kind of
Observation? 

 

Also   most of the definitions of measurement  given on that page consider
measurement to be quantitative, that is assigning numbers.We need to deal
with qualities as well, and packing those qualitative observation inside
framework of measurement with a special unit is a big stretch. (My
understanding that here Matt agreed with Ferdinando) Obviously, observing
sex of an individual {male ,female} does not remotely resemble measurement.
So, how do we then incorporate those qualitative (nominal) classifications
into OBOE.

 

As Josh's summary clearly demonstrates, Measurement, Count and
Classification have common attributes. So, why do not we have a common
superclass for them.   If it is not Observation or AtomicObservation, then
what it can be?

 

-sergey

 

 

 

 

 

 

 

 

 

> 

> Also, we need to be very careful about talking about data structure when

> we talk about oboe.  Not all day is tabular -- and so it is a mistake to

> design oboe to only work with data formatted this way.

> 

> -shawn

> 

> 

> > In the pdf files, where Josh explicatde examples given

> > by Matt and Mark the attribute C (which, as  Shawn  explained to me

> means

> > hasMeasuredCharacteristic)  was used to create n-ary relations. If we

> refuse

> > measurement(0:n), count(0,n) classification (0,1), then we have to

> refuse

> > hasMeasuredCharacteristic too. If we don't, then Classification and

> Count

> > and Measurement will inherit this attribute and we again land in the

> same

> > mess. So how do we now create n-ary relation? In Ferdinando's proposal

> > Observation can be CompoundObservation and AtomicObservation. Later on

> > Ferdinando took back idea of CompoundObservation, but then what do we

> have

> > instead, may be we just need a better name?

> >

> > 4. Personally I like the idea of how Ferdinando's proposal takles

> dichotomi

> > between complex (compound) observations and the other things such as

> Count,

> > Measurement and Classification. I like his idea of ObservationSpace.

> What I

> > do not like is that Observables can be both Entities and

> Characteristics.  I

> > think this is an overkill: Entity (thing, object) and Characteristic

> > (property)  are two fundamental phylosophical categories. Further

> > generalisation over fundamental phylosophical categories warants a big

> mess

> > and missunderstanding.  I will gaet back later with my comments on

> > Ferdinando's proposal

> >

> >

> >

> >

> >

> >

> >

> >   _____

> >

> > From: seek-kr-sms-bounces at ecoinformatics.org

> > [mailto:seek-kr-sms-bounces at ecoinformatics.org] On Behalf Of Joshua

> Madin

> > Sent: Wednesday, June 21, 2006 3:57 PM

> > To: seek-kr-sms at ecoinformatics.org

> > Subject: Re: [seek-kr-sms] OBOE discussion: current version

> >

> >

> >

> > Based on the comments this morning I have redrawn the core of oboe for

> > discussion (attached pdf). It seems to me that the unit-at-all-cost

> > framework will greatly simplify what we are trying to deliver for

> improving

> > data integration, but, as Ferdinando said, this framework will be hard

> to

> > justify and may cause problems down the line. In the attached ontology,

> I've

> > tried to divide the different notions of "measurement". All this does is

> > restrict the properties that can be used on different types of

> observation.

> >

> >

> >

> > I've also included "hasProcedure" as a properties that acts on

> Observations.

> > This can also act on Measurements due the the subsumption hierarchy

> shown in

> > Figure A. I think that this is what Ferdinando meant, but I'm not sure.

> >

> >

> >

> > Cheers. BTW: I just received new emails from Ferdinado and Matt -- but

> I'll

> > send this anyway.

> >

> > Josh

> >

> >

> >

> >

> >

> > >1. Observable is either Entity or Characteristic (at the moment).

> > Characteristic has only one subclass Dimension, which defines the set of

> > base quantities such as length, weight, etc. , Dimension includes only

> > things measured in quantities. Thus at the moment we are missing

> > specification for observations of such characteristics as color, smell,

> > taste or anything which is measured in qualitative scale.

> >

> > This is a question that has come up a lot recently and really needs to

> be

> > confronted with some good examples. The idea was that nominal

> measurements

> > would just be given unit "name" and a characteristic, such as "red".

> This

> > would mean having these characteristics in an extension ontology such as

> a

> > "classifiation ontology" (which would plug into OBOE's charactersitic).

> >

> > I don't think this is right. Simply, the values of that observation come

> > from a finite set of color classes (or instances). Not a measurement, if

> we

> > define measurement as comparison with a reference unit (meter of tree)

> using

> > an abstract unit for the dimension (meter for length).It is ameasurement

> if

> > we define measurement to encompass assigning a class to an observable in

> a

> > context as the result of measuring it. I'd rather call it a

> > "Classification", subclass of Observation and siblings of Measurement.

> And

> > we could have "Ranking" as subclass of Classification, where classes

> must

> > have an ordinal relationship. But stretching the definitionto make it

> fit in

> > the unit-at-all-costs framework and giving the characteristic the role

> of

> > subsetting the value space doesn't sound right at all. This was the

> thought

> > behind proposing an explicit value space.

> >

> > Ordinal measurements may not be as easy to deal with. It might work in

> the

> > same way as above, but use the unit "rank". However, the ordinal

> ontology

> > would need to contain constructs that deal with "direction" or

> "magnitude".

> > For example, "high" is distinct from and of greater magnitude than

> "low".

> > This ontology would have to be able to deal with arbitrary numbers of

> > levels, similar to the way we dealt with Observation in OBOE for coping

> with

> > experimental design. The idea was to remove these kind of things (i.e.,

> > characteristics) from the core ontology because the way that people want

> to

> > use them are so variable.

> >

> > Similar concerns,plus one:I don't think the ordinal relationshipbetween

> > classes such as {high,medium, low} has much of a chance to be captured

> in

> > OWL. Nor I think it should be, as you don't do much with it in workflows

> > unless it'sa realnumeric scale (whose ordinal properties are also not

> > expressed in OWL, so why bother?).If really necessary, we couldmake

> > suchclassificationhierarchies subclasses of"Rank" and use

> anumericproperty

> > for ordering suchvalues, but all the logic necessary to do anythingwith

> it

> > remains outside OBOE.

> >

> >

> >

> > ----------------------------------------------------------

> >

> >

> >

> >

> >

> > Our definition, if I remember correctly, was :Observation is a

> statementthat

> > an Observable has been observed. I think more than this is going to

> > colorOBOEwith restrictions it does not need to have.By the way,we model

> the

> > result of the observation, not the process of the observation, and the

> > result is not an event.To annotate a dataset we don't need to know

> anything

> > about the measurement except its results.

> >

> >

> >

> >

> >

> >

> >

> >

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