Transcript Designing dynamic Earth sciences ontologies

Designing dynamic
Earth sciences ontologies
Process and Event Ontologies
Hassan Babaie
Georgia State University
Ontologies should not just describe
the spatial things in the world

Ontologies should
characterize the
structure of the
world; i.e., the interrelationships
between the objects
occupying
spacetime, and the
facts and constraints
about them
Sheep
Mountain
Anticline WY

What matters in an
ontology is the way the
constituent objects are put
together (i.e., structure),
their characteristics, and
the relations between them
Image from: http://www.earthscienceworld.org/images
Can we formalize this
statement?
“The folding of the Late Cretaceous
sedimentary units, which was the
last phase of a prolonged contractional process,
was followed by uplift, which translated the
deformed rocks to the surface and exposed them
to weathering and erosion during Eocene. This
was followed by continued erosion, which partly
overlapped with the deposition of Oligocene
fluvial sediments, which were deposited through
a sudden flood event in a channel that formed
above the erosional surface.”
Image from: www.grisda.org/colorado/index.htm
Processes shown in yellow

“The folding of the Late Cretaceous sedimentary units,
which was the last phase of a prolonged contractional
process, was followed by uplift, which translated the
deformed rocks to the surface and exposed them to
weathering and erosion during Eocene. This was
followed by continued erosion, which partly overlapped
with the deposition of Oligocene fluvial sediments,
which were deposited through a sudden flood event in
a channel that formed above the erosional surface.”
Temporal components

“The folding of the Late Cretaceous sedimentary units,
which was the last phase of a prolonged contractional
process, was followed by uplift, which translated the
deformed rocks to the surface and exposed them to
weathering and erosion during Eocene. This was
followed by continued erosion, which partly overlapped
with the deposition of Oligocene fluvial sediments,
which were deposited through a sudden flood event in
a channel that formed above the erosional surface.”
Substantial entities

“The folding of the Late Cretaceous sedimentary
units, which was the last phase of a prolonged
contractional process, was followed by uplift, which
translated the deformed rocks to the surface and
exposed them to weathering and erosion during
Eocene. This was followed by continued erosion,
which partly overlapped with the deposition of
Oligocene fluvial sediments, which were deposited
through a sudden flood event in a channel that formed
above the erosional surface.”
All parts of the statement shown

“The folding of the Late Cretaceous sedimentary
units, which was the last phase of a prolonged
contractional process, was followed by uplift, which
translated the deformed rocks to the surface and exposed
them to weathering and erosion during Eocene. This
was followed by continued erosion, which partly
overlapped with the deposition of Oligocene fluvial
sediments, which were deposited through a sudden flood
event in a channel that formed above the erosional surface.”
Static and dynamic aspects of reality

It’s the facts about the things in the world, e.g.,
relation to processes that change them, not the
things themselves that matter

Ontologies need to depict both static and
dynamic aspects of the domain of discourse
Two categories of entities in reality

Entities that occur on the surface of Earth,
below its surface, and in the atmosphere
around it, can be grouped into two general,
non-overlapping categories based on their
mode of existence and persistence:
1.
2.
Endurants
Perdurants
Endurants (Continuants)

Include substantial entities
(both material and immaterial)
e.g., fault, rock, river, aquifer,
pore, cave, glacier, and gas

Occur and interact (through
processes) in the lithosphere,
hydrosphere, atmosphere, and
cryosphere
San Andreas Fault
Photo by:
Robert E. Wallace
pubs.usgs.gov
Qualitative changes to endurants in time
 Connectivity
(topological relations)
 Dimension; e.g., a fault eroding into a 2D trace
 Position
 Location
– defined by distance & direction
 changes by: translation, rotation
 Orientation
 Size
 Shape
 Configuration
(structure)
Perdurants

The perduring entities
(perdurants) include the
processes and events that
involve the endurants

These include such things as
eruption, displacement
(process), deformation and
flow (process aggregate),
and the instantaneous part www.geo.mtu.edu/volcanoes
/hazards/primer/images/
of the beginning phase of a volc-images/puuoo.jpg
landslide (event)
Mereology of endurants e.g.,
SAF

An endurant is part of
reality that occupies
spatial regions at different
or same times, and has
spatial parts

At each instant of time,
occur in its entirety

Preserves its identity
through time despite
continuous qualitative
change
Wood River’s spatial parts: meanders, channel,
flood plains, point bars, occupy spatial regions
Spatial Region:
U.S.A, Alaska;
Fairbanks
Latitude: 64.8
Longitude: -147.7
(www.earthscienceworld.org), © Society for Sedimentary Geology
Mereology of Perdurants

A perdurant (occurrent) entity
(e.g., process, event), on the other
hand, occurs in an interval of
time through a succession of
temporal parts (i.e., phases), that
each occur in subintervals of time

A process unfolds itself over
time, and at each time slice
(instant, t), it presents an
incomplete part of the whole; i.e.,
it is mereologically incomplete at
t. Need a video!
Slumgullion Earthflow,
Hinsdale, Colorado
http://landslides.usgs.go
v/learningeducation/slumg
ullion.php#aerial
Hurricane as a process

Hurricane Katrina:

Time interval:
Started: August 23, 2005 (Wikipedia.com)
 Dissipated: August 31, 2005


Highest winds involved in the hurricane (280 km/h)
The whole process unfolded over the interval
 Only parts of it were seen at every instant
 Different snapshots of it are temporal parts
(phases)!

Hurricane Katrina: A phase of the
process in a spatio-temporal region
This first image
was taken at 03:24
UTC 28 August
2005 (11:24 pm
EDT 27 August)
just as Katrina
was about to
become a
Category 4
hurricane in the
central Gulf of
Mexico.
www.nasa.gov
Another temporal part in a different spatiotemporal region; hurricane is changed
The second
image was taken
at the same time
on 29 August
2005 and shows a
3D perspective
of Katrina with a
cut-away view
through the eye
of the storm.
www.nasa.gov
Unfolding of phases of the Sumatra
Tsunami over an interval of 3 hours on
December 26, 2004
Each snapshot only shows a temporal part, but
not the whole! To see the whole we need the video!
Simulation: Kenji Satake, Geological Survey of Japan, AIST
http://www.notur.no/notur2005/kenjisatake.htm
Basic Formal Ontology, BFO
Institute for Formal Ontology and Medical Information Science, University of Leipzig

Developed at a highest and most domain-neutral level of
generality (Grenon, 2002, 2003)

Applies equally to Earth sciences as it does to biology

The bi-categorical BFO ontologies include the two
endurant and perdurant perspectives, which are referred
to as SNAP and SPAN ontologies, respectively

BFO has similarities and differences (Grenon, 2003)
with the top-level DOLCE ontology
SNAP & SPAN ontologies
(Grenon & Smith, 2003; Grenon, 2003c)

SNAP ontologies represent snapshot
perspective on reality

SPAN ontologies characterize a fourdimensional view and hence a temporal aspect
of existence

These ontologies characterize the static and
dynamic views of the world, respectively
Measuring Change

Change in a SNAP ontology may be measured by
comparing the discrepancies (from snapshots) among
the qualities (e.g., shape, location) of the continuants
measured at different time indexes, t

However, change and dynamic reality can better be
captured through SPAN entities (e.g., processes) which
unfold themselves over an interval of time (t)
SNAP Hierarchy
Our domain entities ‘specialize’ these top-level
classes through the ‘is-a’ relation
(1) Independent SNAP entities

Substantial entities


Aggregates of substances


e.g., unconformities, contacts, grain boundary
Fiat parts (vs. bona fide parts)


e.g., a sequence of rock layers at all scales
Boundaries


e.g., mineral, river
e.g., the equator, 30o N latitude, U.S. Canada border
Sites, which include empty spaces

e.g., cavity, pore, cave, and conduit
(2) Dependent SNAP entities

Could be monadic (e.g., mineral density)






or relational, e.g., sutured or unconformable contact
Qualities (tropes) (e.g., density, color, temp.)
Functions (river transports sediment load)
Conditions (altered/unaltered, dormant/active
Shape (clast shape, sigmoidal megacryst)
Role (role of water in hydraulic fracturing or
hydrolytic weakening)
SPAN Hierarchy
Our domain processes/events ‘specialize’ these
top-level classes through the ‘is-a’ relation
(1) SPAN Processuals entities

Processes - e.g., alteration of rocks at the surface;
mylonitization in a shear zone

Instantaneous temporal boundaries, i.e., events
e.g., the instant a meteorite hits the Earth
 the instant a landslide starts to move


Temporal aggregates, i.e., a successive series of
processes that lead into one another

e.g., the arrival of series of body and surface waves to
a location at different times, and the consequent
compressional or shear particle motion
SPAN entities cont’d

(2) Temporal regions which are part of time and
could be scattered or connected


intervals and instants
(3) Spatio-temporal regions which are part of
spacetime

can also be scattered or connected
Processes have
patterns/structure

Spacetime is punctuated by a series of events that mark
the beginning and end of processes that lead to
qualitative change in endurants

Some of these processes coincide or overlap in time
and space

Processes can occur synchronically (i.e., within same
time intervals) or di-, poly-chronically, involving same
or different objects, in the same or different spatial
regions
Laplace causal determinism

“The idea that every event is necessitated by antecedent events
and conditions together with the laws of nature” (Stanford
Encyclopedia of Philosophy)

The enduring entities provide the spatial location for the events
by participating in these processes

However, the span of processes, which is the spatio-temporal
region in which the process occurs (Simons, 1987), depends on
(i.e., determined by) the spatial and temporal distribution of the
qualitative features of rocks and external fields (e.g., gravity,
stress/strain field) (Laplace determinism)
Examples of causal determinism

Landslide: the transition from stable to unstable states in a
landslide depends on the angle of slope, which relates to
gravitational field, amount of clay and water along the potential
plane of failure, and existence of discontinuities (e.g., fractures)

Volcanic eruption, depends on such things as presence and
type of magma, heat, and strength of the rocks

Fault zone, the processes of sliding and earthquake are
controlled by the far-field as well as local stresses, and the
conditions along the fault, such as pore fluid pressure, and rock’s
mechanical and chemical properties
Ontologies of events/processes
require ontology of time

Ontologies should include both the spatial and
temporal aspects of reality

It is only through events and processes and other
perdurant entities, during which changes occur to
spatial entities and regions, that time becomes
meaningful

“It is neither the point in space, nor the instant in time, at
which something happens that has physical reality, but only the
event itself” Albert Einstein (quoted in: Kennedy, 2003)
Formalization of instants of time

Instants define ‘state transitions’ by events

Like real numbers, time is a continuum of an
unbounded number of possible parts that follow each
other in an ordered succession


‘t1  t2’ reads: ‘t1 precedes t2‘, or ‘t1 is earlier than t2‘, or
‘t1 is before t2‘
Irreflexive relation: no instant precedes itself
t (t  t)
Which says: for all t, t does not precede itself
Time instant is transitive
 For
all instants t, t, t, if t precedes t
and t precedes t, then t precedes t
Unbounded time

For any instant t, there is always another
instant t, which precedes it
i.e., for all t, there exists a t where t is
earlier than t
Subintervals

Subintervals in which related processes occur:
Dense time

Time is also dense like real numbers, meaning that if an
instant t precedes another instant t, there is another
instant in between them which is later than the first and
earlier than the second instant:
i.e., for all t and t, if t is earlier than t, there exists
another instant t where t precedes t, and t precedes t
Time is discrete

An instant t’ is called the ‘immediate successor’
of another instant t, if t precedes t’, and there is
no other instant between them
i.e., t is earlier than t and there is no instant t
between t and t
Intervals of time
in which processes occur

Thirteen exhaustive, mutually exclusive, basic
relations for linear and totally ordered time are
defined by Allen (1983, 1984)
This is done using the ‘immediate precedence’
relation in which the end of interval ‘i’ is
simultaneous with the beginning of interval ‘j’,
denoted by:
ij (reads: i meets j)

end(i) = beg(j)
1
‘i’ meets an interval which meets j end(i) < beg (j)
Interval between two seismic events. Erosion after a period of uplift
2
Primitive end(i) = beg(j)
End of hydraulic fracturing immediately initiating flow of fluid in a reservoir
End of crystallization out of magma immediately followed by crystal settling
3
Some final subinterval of i is an initial subinterval of j
beg(i) < beg(j) < end(i) < end(j)
Eruption of lava partly overlapping continued extension
Interval ‘i’ ends before ‘j’: k, l (ik  kl  jl)
4
i is an initial subinterval of j beg(i) = beg(j)  end(i) < end(j)
Recrystallization and shearing starting at the same time
Synchronous of dialation and uplift
i and j begin together: k (kI  kj), k is initial subinterval of both
5
i is an internal subinterval of j beg(j) < beg(i)  end(i) < end(j)
Contractional tectonics with a period of magmatic intrusion
Melting period during frictional sliding
6
‘i’ is a final subinterval of ‘j’ beg(j) < beg(i)  end(i) = end(j)
End of pyroclastic ejection ending a period of volcanic eruption
‘i’ and j end together: k (ik  jk) and k is subinterval of both
7
i = j beg(i)=beg(j)  end(i)= end(j)
Synchronous folding and thrusting in an area
Synchronous heating and melting
8
j is a final subinterval of i
beg(i) < beg(j)  end(i) = end(j)
Deformation and uplift ending sedimentation
in a basin
9
j is an internal subinterval of i
Period of cataclastic flow during brittle
deformation
10
j is an initial subinterval of i
Interval of magma rising initiating a volcanic
eruption
11
Some final subinterval of j is an initial
subinterval of i
Interval of veining overlapping with fracturing
12
j meets i
Flow coming to an end, initiating deposition in a
delta
13
j meets an interval which meets i
Sea level rising after sea floor spreading
Subduction of oceanic lithosphere after a period
of spreading
Perdurant ‘is-a’ and ‘part-of ’
relations

A process P is-a subclass of another process P1, if for
all p, if p is instance of P, then p is also an instance of
P1


For example, in the Oxidation is-a Weathering, or Folding is-a
Deformation, instances of Oxidation and Folding are also
instances of Weathering and Deformation, respectively
A process P is part-of P1 if and only if an instance of P
is also an instance-level part-of P1 (Smith et al., 2005)

For example, Rotation part-of Cataclasis
Shearing part-of Frictional_Sliding
Other perdurant relation

The has-participant ternary relation relates an instance of
a process p to an instance of a continuant, c at time t
(p has-participant c at t). For example:



Hydrolytic_Softening has-participant Water at t
Folding has-participant Dike at t
The occurring-at relation relates an instance of a process,
p, to time t (p occurring-at t). For example:
Recrystallization occurring-at t
Other relations …

An instance of a process p preceded-by an instance of
another process, p1 (i.e., p preceded-by p1) if for all t and
t1, if p occurring-at t and p1 occurring at t1, and t1 earlier t

Earthquake preceded-by Dilatation and Fracturing

The has-agent relation is a ternary relation between a
process, a causally responsible continuant and time (p
has-agent c at t).

Only continuants (not processes) can be agent


Hydraulic_Fracturing has-agent Water at t (due to its
pore_fluid_pressure quality)
Fracturing has-agent Stress at t