Life cycle data for process plant: Reference data for observations and measurements: 4.5 Variation of property


Life cycle data for process plant: Reference data for observations and measurements	ISO/WD 15926-x:200x(E)

Cover page
Table of contents
Copyright
Foreword
Introduction
1	Scope
2	Normative references
3	Terms, definitions, abbreviations and symbols

4	Observations and measurements reference data
	4.1	Introduction to observations and measurements reference data
	4.2	Observing activity
	4.3	Information
	4.4	Temporal part and time
	4.5	Variation of property
	4.6	Monitoring activity
	4.7	Monitoring criterion

A	Information object registration
B	Document URN
C	Reference data relationships
D	Reference data as OWL
E	Temporal part example
Bibliography
Index

4.5 Variation of property

4.5.1 A variation of property as an object

A property of a whole possible_individual_during_period can vary from instant to instant.

EXAMPLE 1 The mass of MyTank and its contents varies from instant to instant during 2008-08-14 whilst the tank is being filled.

A property of a possible_individual_at_instant can vary from point to point within it.

EXAMPLE 2 The density of the fluid within MyTank at 2008-08-14T10:30:15 varies from point to point within the tank.

A variation_of_property is an object about which statements can be recorded.

EXAMPLE 2 The variation of the mass of MyTank and its contents during 2008-08-14 is the variation_of_property "mass_of_MyTank_during_2008-08-14". The following statement can be recorded:

mass_of_MyTank_during_2008-08-14 is increasing

Expressed formally, this statement is:

http://www.example.com/property_variation/mass_of_MyTank_during_2008-08-14
   a                iso15926-x:going_up .

4.5.2 Observing a variation of property

A measuring_activity can measure a property of a iso15926-2:possible_individual which varies. The result can be:

a statement about a portion of the variation from t₁ to t₂, where t₁ and t₂ are probably within the duration of the measuring_activity; or
an estimate of the value of the property at t₃, where t₃ is probably within the duration of the measuring_activity.

EXAMPLE Consider measuring the level of Lake Como with respect to a datum. The objective of the measuring_activity can be recorded in two ways:

without the use of variation_of_property

:MyMeasurementOfTheLevelOfLakeComo
    a                                           iso15926-x:measuring_activity ;
    iso15926-x:observes                         myOnt:LakeComo ;
    iso15926-x:observes_physical_property       myOnt:levelOfLake .

with the use of variation_of_property

:MyMeasurementOfTheLevelOfLakeComo
    a                                           iso15926-x:measuring_activity ;
    iso15926-x:observes_variation_of_property   :levelOfLakeComo .

:levelOfLakeComo
    a                                           iso15926-x:variation_of_property ;
    rdfs:domain                                 myOnt:LakeComo .
    rdfs:subPropertyOf                          myOnt:levelOfLake ;

The result of the measuring_activity can the statement that the level has an annual cycle. This statement requires the use of the object levelOfLakeComo, and can be recorded as follows:

:MyObservationOfTheLevelOfLakeComo
    a                                           iso15926-x:measuring_activity ;
    iso15926-x:observes_variation_of_property   :levelOfLakeComo .
    iso15926-x:gives_result_formula             :MyStatementAboutTheLevelOfLakeComo
      {  :levelOfLakeComo  a                    myOnt:AnnuallyCyclical } .

4.5.3 Part of a variation of property

One variation_of_property can be a part of another. No special property is needed to record this.

NOTE Within the EXPRESS environment, each variation_of_property is a class_of_relationship, so that "part of" is a subclass relationship. Within the OWL environment, each variation_of_property is a rdf:Property, so that "part of" is a rdfs:subPropertyOf relationship.

Nowever, it may be necessary to be more precise where the domain of one variation_of_property is a sub-manifold of the domain of the other (see part_of_variation_of_property).

EXAMPLE 1 The variation_of_property levelOfLakeComoIn1995 is a part of levelOfLakeComoFrom1990To2000. This can be recorded as:

:levelOfLakeComoIn1995
         iso15926-x:part_of_variation_of_property  :levelOfLakeComoFrom1990To2000 .

It may be convenient to specify that one variation_of_property is partitioned into a set of part instances of variation_of_property, such that:

the members of the set do not overlap;
the assembly of the members of the set is the whole.

The relationship between a variation_of_property and such as set of parts is a variation_of_property_has_partition.

EXAMPLE 2 The variation_of_property levelOfLakeComoFrom1990To2000 can be partitioned into eleven annual instances of variation_of_property. This can be recorded as:

:levelOfLakeComoFrom1990To2000
    iso15926-x:variation_of_property_has_partition
       [ owl:oneOf( :levelOfLakeComoIn1990
                    :levelOfLakeComoIn1991
                    :levelOfLakeComoIn1992
                    :levelOfLakeComoIn1993
                    :levelOfLakeComoIn1994
                    :levelOfLakeComoIn1995
                    :levelOfLakeComoIn1996
                    :levelOfLakeComoIn1997
                    :levelOfLakeComoIn1998
                    :levelOfLakeComoIn1999
                    :levelOfLakeComoIn2000 ) ] .

4.5.4 Variation of a property with respect to time

A time_variation_of_property is a special case of a variation_of_property where the domain is a 1D manifold of temporal instants of a iso15926-2:possible_individual.

A time_variation_of_property can be associated with a period of time by:

recording the temporal part of the iso15926-2:possible_individual for which temporal instants are the domain;
recording the period of time during which the temporal part exists.

It may be more convenient, to record the period of time for a time_variation_of_property directly using a variation_during relationship.

EXAMPLE The variation_of_property levelOfLakeComoIn1997 exists during 1997. This can be recorded as:

:levelOfLakeComoIn1997
    iso15926-x:variation_during
       [ topology:end_1_of_edge [ iso15926-x:utc_iso8601 "1996-12-31T24:00" ] ;
         topology:end_2_of_edge [ iso15926-x:utc_iso8601 "1997-12-31T24:00" ] .

4.5.5 Ontology for variation of property

4.5.5.1 variation_of_property

An object is a variation_of_property if and only if:

it is a basics:function from a manifold of spatial points within, or a instants of, a iso15926-2:possible_individual;
the function is the evaluation of a property.

NOTE OWL specification:

-->
<owl:Class rdf:about="&iso15926-x;variation_of_property">
 <rdfs:subClassOf rdf:resource="&rdf;Property"/>
 <rdfs:subClassOf rdf:resource="&basics;function"/>
 <rdfs:isDefinedBy rdf:resource="&iso15926-x-doc;/variation_of_property.htm#variation_of_property"/>
</owl:Class>
<!--

4.5.5.2 time_variation_of_property

An object is a time_variation_of_property if and only if:

it is a variation_of_property;
the domain is a basics:manifold_1d of instants of the same iso15926-2:possible_individual.

NOTE OWL specification:

-->
<owl:Class rdf:about="&iso15926-x;time_variation_of_property">
 <rdfs:subClassOf rdf:resource="&iso15926-x;variation_of_property"/>
 <rdfs:isDefinedBy rdf:resource="&iso15926-x-doc;/variation_of_property.htm#time_variation_of_property"/>
</owl:Class>
<!--

4.5.5.3 variation_during

An object is a variation_during relationship if and only if:

it is a basics:function from time_variation_of_property to finite_period;
it specifies the finite_period during which the time_variation_of_property exists.

NOTE OWL specification:

-->
<owl:FunctionalProperty rdf:about="iso15926-x;variation_during">
 <rdfs:domain rdf:resource="&iso15926-x;time_variation_of_property"/>
 <rdfs:range rdf:resource="&iso15926-x;finite_period"/>
 <rdfs:isDefinedBy rdf:resource="&iso15926-x-doc;/variation_of_property.htm#variation_during"/>
</owl:FunctionalProperty>
<!--

4.5.5.4 part_of_variation_of_property

An object is a part_of_variation_of_property relationship if and only if:

it is a basics:mapping from variation_of_property to variation_of_property;
it specifies that the the domain of one variation_of_property is a sub-manifold of the domain of the other.

NOTE OWL specification:

-->
<owl:ObjectProperty rdf:about="&iso15926-x;part_of_variation_of_property">
 <rdfs:domain rdf:resource="&iso15926-x;variation_of_property"/>
 <rdfs:range rdf:resource="&iso15926-x;variation_of_property"/>
 <rdfs:isDefinedBy rdf:resource="&iso15926-x-doc;/variation_of_property.htm#part_of_variation_of_property"/>
</owl:ObjectProperty>
<!--

4.5.5.5 variation_of_property_has_partition

An object is a variation_of_property_has_partition relationship if and only if:

it is a basics:mapping from variation_of_property to a set of instances of variation_of_property;
such that:
- the members of the set do not overlap;
- the assembly of the members of the set is the whole.

NOTE OWL specification:

-->
<owl:ObjectProperty rdf:about="&iso15926-x;variation_of_property_has_partition">
 <rdfs:domain rdf:resource="&iso15926-x;variation_of_property"/>
 <rdfs:range>
  <owl:Restriction>
   <owl:onProperty rdf:resource="&rdfs;subClassOf"/>
   <owl:hasValue rdf:resource="&iso15926-x;variation_of_property"/>
  </owl:Restriction>
 </rdfs:range>
 <rdfs:isDefinedBy rdf:resource="&iso15926-x-doc;/variation_of_property.htm#variation_of_property_has_partition"/>
</owl:ObjectProperty>
<!--