An Introduction to ISO15926
Copyright: SIPC
Matthew West
Reference Data Architecture
and Standards
Programme
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Introduction to 4 Dimensionalism
•
ISO 15926-2 – Lifecycle Integration Schema
– Introduction to the data model
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Reference Data Architecture and Standards
3D and 4D approaches to ontology
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In principle, there are infinitely many ways in which we can model the
world, so it is perhaps surprising that there are two main approaches, with
on the whole minor variations, that dominate the literature.We will call
these the 3D paradigm and the 4D paradigm, though they are also known
as endurantism, and perdurantism.
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4D Ontology
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A 4D ontology treats all individuals – things that exist in space-time - as spatio-temporal
extents, i.e. as 4D objects.
The principles of the 4D paradigm are:
1. Individuals exist in a manifold of 4 dimensions, three space and one time. So things in the
past and future exist as well as things in the present.
2. The four dimensional extent is viewed from outside time rather than in the present.
3. Individuals (including physical objects) extend in time as well as space and have both
temporal parts and spatial parts.
4. When two individuals have the same spatio-temporal extent they are the same thing.
(However not all version of 4D insist on this principle).
•
Thus a 4D object is not (usually) wholly present at a point in time, but its whole is extended
in space as well as time. The object at a point in time is a temporal part of the whole. Change
is naturally expressed through a 4 dimensional classical mereology, which Simons: “Parts: A
Study in Ontology” in his seminal work, describes in one page. A good description of, and
argument for, the 4D paradigm can be found in Sider: “4 Dimensionalism”.
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3D Ontology
•
A 3D ontology treats physical objects (roughly things you can kick) as 3D objects
(sometimes called continuants) that pass through time. The principles of the 3D paradigm
are:
1. Physical objects are 3-dimensional objects that pass through time and are wholly present at
each point in time.
2. Physical objects are viewed from the present. The default is that statements are true now.
3. Physical objects do not have temporal parts.
4. Different physical objects may coincide.
5. The object-at-a-point-in-time is the object of primary interest.
•
To talk about an object at different times it is necessary to time index statements in some
way, e.g. X at t. A 3D ontology also has 4D objects in it. These cover activities, such as:
–
a football match - which clearly has temporal parts such as the first half and the second half,
–
a living process - a persons life, rather than the physical person passing through time.
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Reference Data Architecture and Standards
Which paradigm?
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The 3D approach corresponds well with the way that language works. Language
has a focus around here, now, you and me as a context, and on the current state of
affairs. This leads to efficient communication under the most common
circumstances. On the other hand dealing with change is relatively problematic.
Simons requires several chapters to explain how objects change over time in a 3D
ontology.
•
What is clear is that the 3D and 4D paradigms cannot be merged into a single
canonical approach, since they are contradictory, with one requiring physical
objects to have temporal parts, and the other forbidding them.
•
On the other hand, it appears that what can usefully be said using one paradigm
can generally be said using the other.
•
We chose the 4D paradigm because we found it to be rigorous, and gave a good
account of some difficult cases, like replaceable parts.
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ISO15926-2: Integration Model
•
Background
– Originally the EPISTLE Core Model
– Started around 1993
– Now at Version 4.5.1
– As ISO 15926-2 became an International Standard in 2003.
–
2nd October 2001ttp://www.tc184sc4.org/wg3ndocs/wg3n1328/lifecycle_integration_schema.html
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Basic Elements
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Thing
– anything, real or abstract
– Note: the supreme supertype
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Possible Individual (Spatio-temporal extent)
– some part(s) of space-time
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Class
– collection of things, possibly infinite, where the order is not significant
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Relationship
– Something one thing has to do with another.
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Space time map
3D
SPACE
A particular
spatio temporal
extent
TIME
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Thing
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Possible Worlds
Past
Future
Possible
Actual
Desired
Possible
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Possible Individual
T > 0
3D
SPACE
S > 0
TIME
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Whole Individual
Plastic
blank
Cup
Crushed
plastic
TIME
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point in time
T = 0
period of time
T > 0
3D
SPACE
TIME
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Possible Individual/State – Temporal whole-part
Time
period
3D
SPACE
State
Individual
TIME
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Materialised Physical Object
event 1
event 2
3D
space
B
A
D
C
Time
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Functional Physical Object/Replaceable Part
3D
SPACE
installed
removed
installed
removed
Tag 101
pump 1
pump 2
TIME
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Objects that Overlap
John Jennings
Chairman of Shell
Space
Mark Moody-Stuart
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Stream
disconnected
connected
valve
open
valve
close
tank A
3D
space
hose
tank B
start filling
end filling
Time
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Individual
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Activity
Activity
3D
space
Performer
Performer
Input
Input
Output
Output
Time
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Event and Point in Time
Point in time
event
3D
SPACE
T = 0
TIME
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Temporal Boundary
point in time
event
3D
SPACE
Sub state
TIME
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Activity and Temporal Boundary
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Some approaches to Set Theory
A
1
B
2
3
C
4
5
Instances may only be a member of only one set
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Only one level
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Some approaches to Set Theory
X
Y
M
N
O
A
1
Z
B
2
3
P
C
4
5
Instances may only be a member of only one set
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Sets hierarchical (model/meta-model etc)
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Some approaches to Set Theory
X
Y
M
N
O
A
1
Z
B
2
3
P
C
4
5
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Instances may only be a member of one or more sets27
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Sets hierarchical (model/meta-model etc)
Some approaches to Set Theory
X
Y
M
N
O
A
1
Z
B
2
3
P
C
4
5
6
Instances may only be a member of one or more sets28
Reference Data Architecture and Standards
Sets not hierarchical (model/meta-model etc)
Some approaches to Set Theory
X
Y
M
N
O
A
1
Z
B
2
3
P
C
4
5
6
Instances may only be a member of one or more sets29
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Sets not hierarchical (model/meta-model etc). Loops
Class
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Class of Individual
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Organisational Levels
organisation
assembly
organism
simple artefact
molecular
atomic
sub-atomic
“fundamental”
particle
time
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Cup
arrangement of
Plastic
arrangement of
Hydrocarbon
molecules
arrangement of
atoms
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Organisational Levels
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Information
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Information
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Information
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Summary
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A 4D ontology sees physical objects as extended in time as well as space
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ISO 15926 is a data model that is also a 4D ontology
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It uses a possible worlds approach rather than modal logic
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Sets are defined by extension
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Questions?
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