Scientific Reports,
Journal Year:
2023,
Volume and Issue:
13(1)
Published: June 22, 2023
Abstract
Building
reduced-order
models
(ROMs)
is
essential
for
efficient
forecasting
and
control
of
complex
dynamical
systems.
Recently,
autoencoder-based
methods
building
such
have
gained
significant
traction,
but
their
demand
data
limits
use
when
the
scarce
expensive.
We
propose
aiding
a
model’s
training
with
knowledge
physics
using
collocation-based
physics-informed
loss
term.
Our
innovation
builds
on
ideas
from
classical
collocation
numerical
analysis
to
embed
known
equation
into
latent-space
dynamics
ROM.
show
that
addition
our
allows
exceptional
supply
strategies
improves
performance
ROMs
in
data-scarce
settings,
where
high-quality
data-driven
impossible.
Namely,
problem
modeling
high-dimensional
nonlinear
PDE,
experiments
$$\times$$
×
5
gains,
measured
by
prediction
error,
low-data
regime,
10
gains
tasks
high-noise
learning,
100
efficiency
utilizing
dimension,
200
far-out
out-of-distribution
relative
purely
models.
These
improvements
pave
way
broader
adoption
network-based
compressive
sensing
applications.
Transactions of Mathematics and Its Applications,
Journal Year:
2022,
Volume and Issue:
6(1)
Published: Jan. 1, 2022
Abstract
DeepONets
have
recently
been
proposed
as
a
framework
for
learning
nonlinear
operators
mapping
between
infinite-dimensional
Banach
spaces.
We
analyze
and
prove
estimates
on
the
resulting
approximation
generalization
errors.
In
particular,
we
extend
universal
property
of
to
include
measurable
mappings
in
non-compact
By
decomposition
error
into
encoding,
reconstruction
errors,
both
lower
upper
bounds
total
error,
relating
it
spectral
decay
properties
covariance
operators,
associated
with
underlying
measures.
derive
almost
optimal
very
general
affine
reconstructors
random
sensor
locations
well
using
covering
number
arguments.
illustrate
our
four
prototypical
examples
namely
those
arising
forced
ordinary
differential
equation,
an
elliptic
partial
equation
(PDE)
variable
coefficients
parabolic
hyperbolic
PDEs.
While
arbitrary
Lipschitz
by
accuracy
$\epsilon
$
is
argued
suffer
from
‘curse
dimensionality’
(requiring
neural
networks
exponential
size
$1/\epsilon
$),
contrast,
all
above
concrete
interest,
rigorously
that
can
break
this
curse
dimensionality
(achieving
grow
algebraically
$).Thus,
demonstrate
efficient
potentially
large
class
machine
framework.
Physics of Fluids,
Journal Year:
2022,
Volume and Issue:
34(5)
Published: April 25, 2022
The
complex
flow
modeling
based
on
machine
learning
is
becoming
a
promising
way
to
describe
multiphase
fluid
systems.
This
work
demonstrates
how
physics-informed
neural
network
promotes
the
combination
of
traditional
governing
equations
and
advanced
interface
evolution
without
intricate
algorithms.
We
develop
networks
for
phase-field
method
(PF-PINNs)
in
two-dimensional
immiscible
incompressible
two-phase
flow.
Cahn–Hillard
equation
Navier–Stokes
are
encoded
directly
into
residuals
fully
connected
network.
Compared
with
interface-capturing
method,
model
has
firm
physical
basis
because
it
Ginzburg–Landau
theory
conserves
mass
energy.
It
also
performs
well
at
large
density
ratio.
However,
high-order
differential
nonlinear
term
Cahn–Hilliard
poses
great
challenge
obtaining
numerical
solutions.
Thus,
this
work,
we
adopt
tackle
by
solving
derivate
terms
capture
adaptively.
To
enhance
accuracy
efficiency
PF-PINNs,
use
time-marching
strategy
forced
constraint
viscosity.
PF-PINNs
tested
two
cases
presenting
ability
PINNs
evaluating
ratio
(up
1000).
shape
both
coincides
reference
results,
dynamic
behavior
second
case
precisely
captured.
quantify
variations
center
increasing
velocity
over
time
validation
purposes.
results
show
that
exploit
automatic
differentiation
sacrificing
high
method.
Acta Mechanica Sinica,
Journal Year:
2021,
Volume and Issue:
37(12), P. 1718 - 1726
Published: Dec. 1, 2021
Abstract
This
paper
provides
a
short
overview
of
how
to
use
machine
learning
build
data-driven
models
in
fluid
mechanics.
The
process
is
broken
down
into
five
stages:
(1)
formulating
problem
model,
(2)
collecting
and
curating
training
data
inform
the
(3)
choosing
an
architecture
with
which
represent
(4)
designing
loss
function
assess
performance
(5)
selecting
implementing
optimization
algorithm
train
model.
At
each
stage,
we
discuss
prior
physical
knowledge
may
be
embedding
process,
specific
examples
from
field
Graphic
abstract
Acta Numerica,
Journal Year:
2022,
Volume and Issue:
31, P. 265 - 345
Published: May 1, 2022
Numerical
simulation
of
parametrized
differential
equations
is
crucial
importance
in
the
study
real-world
phenomena
applied
science
and
engineering.
Computational
methods
for
real-time
many-query
such
problems
often
require
prohibitively
high
computational
costs
to
achieve
sufficiently
accurate
numerical
solutions.
During
last
few
decades,
model
order
reduction
has
proved
successful
providing
low-complexity
high-fidelity
surrogate
models
that
allow
rapid
simulations
under
parameter
variation,
thus
enabling
increasingly
complex
problems.
However,
many
challenges
remain
secure
robustness
efficiency
needed
nonlinear
time-dependent
The
purpose
this
article
survey
state
art
reduced
basis
draw
together
recent
advances
three
main
directions.
First,
we
discuss
structure-preserving
designed
retain
key
physical
properties
continuous
problem.
Second,
localized
adaptive
based
on
approximations
solution
space.
Finally,
consider
data-driven
techniques
non-intrusive
which
an
approximation
map
between
space
coefficients
learned.
Within
each
class
methods,
describe
different
approaches
provide
a
comparative
discussion
lends
insights
advantages,
disadvantages
potential
open
questions.
Physics of Fluids,
Journal Year:
2022,
Volume and Issue:
34(11)
Published: Nov. 1, 2022
Computational
fluid
dynamics
(CFD)
is
known
for
producing
high-dimensional
spatiotemporal
data.
Recent
advances
in
machine
learning
(ML)
have
introduced
a
myriad
of
techniques
extracting
physical
information
from
CFD.
Identifying
an
optimal
set
coordinates
representing
the
data
low-dimensional
embedding
crucial
first
step
toward
data-driven
reduced-order
modeling
and
other
ML
tasks.
This
usually
done
via
principal
component
analysis
(PCA),
which
gives
linear
approximation.
However,
flows
are
often
complex
nonlinear
structures,
cannot
be
discovered
or
efficiently
represented
by
PCA.
Several
unsupervised
algorithms
been
developed
branches
science
dimensionality
reduction
(NDR),
but
not
extensively
used
flows.
Here,
four
manifold
two
deep
(autoencoder)-based
NDR
methods
investigated
compared
to
These
tested
on
canonical
flow
problems
(laminar
turbulent)
biomedical
brain
aneurysms.
The
reconstruction
capabilities
these
compared,
challenges
discussed.
temporal
vs
spatial
arrangement
its
influence
mode
extraction
investigated.
Finally,
modes
qualitatively
compared.
results
suggest
that
using
would
beneficial
building
more
efficient
models
All
resulted
smaller
errors
reduction.
Temporal
was
harder
task;
nevertheless,
it
physically
interpretable
modes.
Our
work
one
comprehensive
comparisons
various
unsteady
IEEE Access,
Journal Year:
2023,
Volume and Issue:
11, P. 110762 - 110795
Published: Jan. 1, 2023
This
article
presents
a
comprehensive
overview
of
the
digital
twin
technology
and
its
capability
levels,
with
specific
focus
on
applications
in
wind
energy
industry.
It
consolidates
definitions
levels
scale
from
0-5;
0-standalone,
1-descriptive,
2-diagnostic,
3-predictive,
4-prescriptive,
5-autonomous.
then,
an
industrial
perspective,
identifies
current
state
art
research
needs
sector.
is
concluded
that
main
challenges
hindering
realization
highly
capable
twins
fall
into
one
four
categories;
standards-related,
data-related,
model-related,
acceptance
related.
The
proposes
approaches
to
identified
perspective
institutes
offers
set
recommendations
for
various
stakeholders
facilitate
technology.
contribution
this
lies
synthesis
knowledge
identification
future
industry
ultimately
providing
roadmap
development
field