Quantity values without axioms

[l-emele]

Description of the issue

We have a lot of quantity values where the relation to its entity in reality is not expressed with an quantity value of axiom.

Ideas of solution

Workflow checklist

• I discussed the issue with someone else than me before working on a solution
• I already read the latest version of the workflow for this repository
• The goal of this ontology is clear to me

I am aware that

• every entry in the ontology should have a definition
• classes should arise from concepts rather than from words

[l-emele]

For most subclasses of economic value I am asking myself whether these are really quantity values or rather should be entities in reality that have quantity values something like monetary value. For example, to me a fee is conceptually something similar as a levy, but a levy is a SDC while a fee is a quantity value.

[nelekoehler]

I agree, such relations could really be made more often, e.g. electrical energy amount value maybe quantity value of electrical energy. But it also seems to me, for some quantity values there is also not clearly a specific entity they refer to.

With levy and fee I have the impression that they are different, because fee is a monetary amount (thus value) for an object/entity and levy rather a task or demand or social measure for humans. Therefore, the division into quantity value and subclass of policy instrument seems to make sense to me in that case.

[stap-m]

@nelekoehler to get an overview, could please you create a list of quantity values that miss

• either an axiom to an existing entity in reality
• or an entity in reality at all

[nelekoehler]

I created a google sheet, where on the first page I listed alle the quantity values and if they have an axiom (quantity value of ..). On the second page I listed all the quantity value without a relation to its entity, so without the quantity value of … axiom, so that suggestions can be collected there. Here’s the link: https://docs.google.com/spreadsheets/d/1iqttYN3ng9hSmbQNvOpwPi7dg7__dNIjx2GNFUsWRkc/edit?usp=sharing

[stap-m]

I extended the table by a column "entity in reality", to check whether the existing axioms are fine, or not.
E.g. the entity in reality of area value (line 2, first sheet) should probably not be the two-dimensional spatial region itself, but its (areal) size, which might be a quality of the spatial region.

1. '2-dim spatial region' 'has quality' some 'areal size'
2. 'areal size' 'has quantity value' some 'area value'
3. For a specific region e.g.: 'area value' 'has unit' m² and 'has value' 3

We can discuss this also on friday with @fabianneuhaus

[stap-m]

@nelekoehler could you please also check the inverse relation to quantity value of, which is has quantity value and add them to the table. There are not always both directions axiomatised. I added a column to the spreadsheet.

[l-emele]

There are quantity values which are abstract and to not have an entity in reality. One example is fraction value: A fraction value is a quantity value that has a fraction as it's unit. This is a parent class which to classes like renewable energy share value and utilisation value. Maybe we could/should convert those quantity value classes which do not have an entity in reality into equivalent classes, in this case: 'fraction value' EquivalentTo: 'has unit' some fraction.

Also quantity value it self currently has no quantity value of axiom. However, we might add: 'quantity value' EquivalentTo: ('quantity value of' some entity). Then everything which has an quantity value of axiom becomes an quantity value.

[nelekoehler]

After a further discussion, we now also came to the point that not every quantity value needs/has an entity in reality, for example, with relations such as greater than or share of certain group of people in parliament or similar, there is a reference to reality, but no specific entity that inherits the quantitative property. For that, the suggested equivalent classes seem good for implementing the relation to reality without the axiom 'quantity value of'.
A pragmatic approach in dealing with this would be to accept the vocabulary of the domain experts for the time being and to systematize it and, if conflicts arise in the application of it, to question what quantity values refer to.

[UStucky]

I took a look at the class "quantity value" in the OEO and think that on the subclass level to different categories are mixed. I tried to give detailed examples with one category modeled according to a quantity model I once used for a time series generator.
Unfortunately I started with paper and pencil and to save time I simply attach the scan here.
quantityValue.pdf

[UStucky]

I have attached an image with classes from my time series generator.
Here are some explanations:
It contains methods which are irrelevant for our ontology topic. Our quantity and quantity value are represented here as MeasurementValue and MeasurementQuantity. The enumeration UnitExponent represents the prefixes or exponents to the basic units and it can be seen as a class with a fixed set of instances (individuals; NONE - YOTTA) The special classes TimeIn are due to the fact, that they are not all proper units (month and year vary in length and do not represent proper physical units; the others could be used as - partly quite unusual - units, but it is completely unusual to combine them with UnitExponents or prefixes - even Megaseconds and other Xseconds are not very popular, just the negative exponents with seconds are used) Anyway, they can also be modeled as simple Time objects with different basic units (property of superclass UnitQuantity) - except month and year, of course

[stap-m]

From oeo-dev 77:

• define quantity as BFO:quality based on VIM
  • VIM def: a quantity is a „property of a phenomenon, body, or substance, where the property has a magnitude that can be expressed as a number and a reference“
  • Agreement on OEO definition:
    A quantity is a quality of a material entity where the quality has a quantifiably magnitude (i.e. quantity value) that can be expressed as a number and a unit.
• implement quantity and check, which entities have to be reclassified as such (probably some qualities) @nelekoehler
• next steps:
  • review existing quantity values for
    • missing/correct quantities and process attributes
    • missing/correct axioms to quantities and process attributes

[l-emele]

• A quantity is a quality of a material entity where the quality has a quantifiably magnitude (i.e. quantity value) that can be expressed as a number and a unit.

• implement quantity and check, which entities have to be reclassified as such (probably some qualities) @nelekoehler

According to this, energy also gets reclassified as quantity, right?

[UStucky]

It depends; the physical quantity energy, of course, is a quantity according to the above given definition. But there may be other - more colloquial - uses of the term or terms containg the word energy that do not denote the strictly defined physical quantity energy. E.g most of the subclasses of energy may denote rather a energy type than a certain amount of energy in J or some other unit

[l-emele]

Of course I am talking about definition and implementation in the OEO.

[stap-m]

• A quantity is a quality of a material entity where the quality has a quantifiably magnitude (i.e. quantity value) that can be expressed as a number and a unit.
• implement quantity and check, which entities have to be reclassified as such (probably some qualities) @nelekoehler

According to this, energy also gets reclassified as quantity, right?

Since we decided to make quantity equivalent to quality and ('has quantity value' some 'quantity value'), we actually don't need to reclassify. energy will be inferred as quantity if we added an axiom to a quantity value, e.g. energy amount value.

[l-emele]

Yes, true. I just wanted to make sure, that we agree, that energy is also a quantity.