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Re: [ontology-based-standards] small follow-up on RE: "Ontology-based St

To: ontology-based-standards@xxxxxxxxxxxxxxxx
From: Tara Athan <taraathan@xxxxxxxxx>
Date: Sat, 19 Oct 2013 12:29:58 -0400
Message-id: <5262B386.8080503@xxxxxxxxx>
Simon- I wouldn't call this a definitive reference, but this treatment agrees with my recollection from physical chemistry

http://www.edinformatics.com/math_science/suspensions_colloids.htm

The continuum is solution (= homogeneous mixture) - colloid - suspension (=heterogeneous mixture) and at the extreme end, separate phases rather than a mixture. An emulsion is a type of colloid that involves only liquids. This distinction presumes a particular "scale" is interest - the molecular scale. With this assumption, and the criteria of the significance of Brownian motion, I would say that Brownian motion is not, under any conceivable scenario, a significant factor in the motion of crocodiles and so crocs are neither dissolved nor colloidal particles (not that you were suggesting they were, I just take the extreme case to make a point). However as to particles in general there is some fuzziness. There is not a sharp cut off where Brownian motion changes from significant to insignificant.

Similarly there is not a sharp cutoff between suspended particles and separated phases. As described here (http://en.wikipedia.org/wiki/Sediment_transport), particle Reynolds numbers, dimensionless parameter dependent on characteristics of the particle as well as the flow, can be used to characterize the system. In borderline cases, judgement is required to select the appropriate particle Reynolds number for the intended purpose.

In all such cases of classification, there are multiple reasons to question the observation. Accuracy of such observations can be themselves estimated - higher accuracy for a classification based on a more accurate estimate of a continuous property, lower accuracy when the property estimate falls into the borderline zone of the soft classifier. This is admittedly mixing uncertainty from different kinds of sources (errors in observation with soft classification) into a common "confidence" estimate - that's what Bayesians do, and I'll confess to being an unrepentant Bayesian.

I believe an examination of soft classification from the perspective of Bayesian statistics would be helpful to the ontological community in getting a grip on the capabilities and limitations of the hard classifications that appear to be built into the less expressive KR languages. There is a large body of work on this problem, and it is not a good use of our time to reinvent this wheel.

Tara

On 10/18/13 10:37 PM, Simon.Cox@xxxxxxxx wrote:

Maybe. But it also depends on the size of the pipe and the rate of flow.

 

The reason that crocodiles are interesting is

(a)     In this context they are not fundamentally different to any other kind of suspended particle.

(b)    They are a real water quality indicator, both in terms of the capacity of a water body to support life, and the capacity of the water body to support recreation!

(c)     They are memorable!

 

It seems that Torsten and Boyan are suggesting there is a fundamental distinction between dissolved and suspended contaminants, but I’m not sure there is a firm line. When I did physical chemistry there was a continuum from solution-suspension-emulsion-colloid, but in the case of suspension I’m not sure if there is a critical particle size – look at the movies from the Fukushima tsunami to see how very large objects can be part of the flow.

 

You also appear to be accepting that hydrodynamics is the use-case under discussion. There are other cases in which water contaminants play a role.

 

Simon

 

From: ontology-based-standards-bounces@xxxxxxxxxxxxxxxx [mailto:ontology-based-standards-bounces@xxxxxxxxxxxxxxxx] On Behalf Of Alex Shkotin
Sent: Friday, 18 October 2013 6:54 PM
To: ontology-based-standards
Subject: Re: [ontology-based-standards] small follow-up on RE: "Ontology-based Standards" mini-series session-5 - Ontologies for Geospatial Standards - Thu 2013.10.17

 

Simon,

 

I think it's just more simple: Torsen gave us elements of hydrology theory (formal one;-) abstracted from bio-objects.

Suppose this theory can predict flood movement and other hydrology processes.

But where crocodiles? They are neglected. Abstraction.

They do not impact to hydrological processes of interest. Do they?

Ask hydrologists:-)

I think they have an amendment to the coefficient of viscosity of the water in this case;-)

 

Alex

 

2013/10/18 <Simon.Cox@xxxxxxxx>

Re the discussion about water/crocodiles/water bodies etc:

This issue is partly accommodated by the O&M model, where the 'feature-of-interest' (e.g. a specific water body) is distinguished from the 'observed-property' (concentration of crocodiles) (and also from the procedure or sensor).
This in turn is a corollary of the underlying 'feature model' which, like pretty much all of the meta-models we are using including OWL, distinguishes between classes/objects and properties/property-values.

There is an issue that many vocabularies of 'observed properties' conflate these concerns, so in standard water property vocabularies we see entries like:
   'concentration of crocodiles in a water body measured using a fooglemeter averaged over 3-day intervals and expressed as a number scaled by the unit-of-measure "bites"'.

But the analysis is established in O&M since many years now.

Simon

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