International Journal of Coal Preparation and Utilization,
Год журнала:
2024,
Номер
unknown, С. 1 - 26
Опубликована: Дек. 10, 2024
To
increase
the
accuracy
of
clean
coal
ash
content
prediction
during
dense
medium
separation
process
and
address
time
lag
issue
encountered
when
measuring
content,
a
model
based
on
WaOA-VMD-SGMD-WaOA-LSTM
was
proposed.
The
adopts
dual
decomposition
techniques
optimized
Variational
Mode
Decomposition
(VMD)
Symplectic
Geometric
(SGMD),
which
can
completely
decompose
original
data,
uses
Walrus
optimization
algorithm
(WaOA)
to
optimize
hyperparameters
Long
Short-Term
Memory
(LSTM)
model.
In
construction,
characteristic
data
ore
(𝑍2),
raw
(𝑍3),
heavy
mesoporous
cyclone
pressure
(𝑍4),
suspension
density
(𝑍5),
magnetic
(𝑍6)
were
combined
with
decomposed
cleaned
grouping
S-IMF0~S-IMFn,
CO-IMF1,
CO-IMF2
as
input
variables
construct
multiple
LSTM
models.
Finally,
value
is
superimposed
realize
content.
Based
industrial
preparation
plant
in
Shanxi,
China,
results
show
that
coefficient
determination
(R2)
0.9974.
After
adding
secondary
technology,
average
absolute
error
reduced
by
60.99%
compared
single
strategy.
Frontiers in Energy Research,
Год журнала:
2024,
Номер
11
Опубликована: Янв. 11, 2024
Carbon
trading
prices
are
crucial
for
carbon
emissions
and
transparent
market
pricing.
Previous
studies
mainly
focused
on
data
mining
in
the
prediction
direction
to
quantify
prices.
Although
prospect
of
high-frequency
forecasting
mechanisms
is
considerable,
more
mixed-frequency
ensemble
needed
Therefore,
this
article
designs
a
new
type
model
increase
scope
research.
The
module
divided
into
three
parts:
denoising,
mixed
frequency
machine
learning,
multi-objective
optimization,
forecasting.
Precisely,
preprocessing
technology
enhanced
by
adopting
self-attention
mechanism
can
better
remove
noise
extract
effective
features.
Furthermore,
introduced
learning
achieve
comprehensive
efficient
prediction,
evaluation
criterion
proposed
measure
optimal
submodel.
Finally,
based
deep
strategy
effectively
integrate
advantages
low-frequency
complex
datasets.
At
same
time,
optimization
algorithm
optimize
parameters
model,
significantly
improving
predictive
ability
integrated
module.
results
four
experiments
Mean
Absolute
Percent
Error
index
improved
28.3526%
compared
models,
indicating
that
established
address
time
distribution
characteristics
uncertainty
issues
predicted
price
which
helps
mitigate
climate
change
develop
low-carbon
economy.
Crude
oil
price
volatility
forecasting
is
important
for
energy
policymaking
and
investment
risk
avoidance,
which
has
attracted
significant
global
attention.
Due
to
the
non-stationary
non-linear
characteristics
of
crude
volatility,
it
a
great
challenge
its
forecasting.
In
order
describe
uncertainty
provide
richer
information
than
point
results,
an
improved
hybrid
interval
prediction
model
containing
signal
processing,
sequence
complexity
judgement,
construction
machine
learning
methods
proposed.
Firstly,
original
decomposed
reconstructed
into
several
new
sequences
with
different
by
ICEEMDAN-FE.
Secondly,
are
fuzzified
obtain
upper
bounds
lower
interval.
Then,
high-frequency
predicted
IESN,
low-frequency
residual
term
ARIMA.
Finally,
The
final
result
formed
sum
each
bound
result.
WTI
spot
Brent
selected
analysis,
consider
influence
futures
on
construction.
effect
intervals
validated
from
pricing
benchmark
time
scale
dimensions,
respectively.
By
analyzing
reasons
outstanding
interval,
can
be
judged
that
proposed
provides
idea
prices.
Physica Scripta,
Год журнала:
2024,
Номер
99(9), С. 096003 - 096003
Опубликована: Авг. 2, 2024
Abstract
To
solve
the
problem
of
difficulty
in
selecting
multi-parameter
features
ocean
and
lack
power
traditional
time-series
prediction
models
predicting
data,
an
GRU
model
based
on
Borutashap
algorithm,
a
hybrid
multivariate
empirical
modal
decomposition
is
proposed
to
predict
this
paper.
The
feature
selection
multi-feature
data
carried
out
by
algorithm
XG-boost
model,
then
selected
are
decomposed
multi-modal
decomposition,
reconstructed
get
high-frequency
low-frequency
components,
trend
term
components
Permutation
Entropy,
finally
respectively
brought
into
network
summed
up
final
result.
In
paper,
model’s
effectiveness
verified
ablation
experiments
compared
with
other
classical
time
series
models,
results
show
that
has
better
effect.
Atmosphere,
Год журнала:
2024,
Номер
15(9), С. 1091 - 1091
Опубликована: Сен. 8, 2024
Understanding
the
spatiotemporal
dynamics
of
atmospheric
PM2.5
concentration
is
highly
challenging
due
to
its
evolution
processes
have
complex
and
nonlinear
patterns.
Traditional
mode
decomposition
methods
struggle
accurately
capture
features
concentrations.
In
this
study,
we
utilized
global
linearization
capabilities
Koopman
method
analyze
hourly
daily
in
Beijing–Tianjin–Hebei
(BTH)
region
from
2019
2021.
This
approach
decomposes
data
into
superposition
different
spatial
modes,
revealing
their
hierarchical
structure
reconstructing
dynamic
processes.
The
results
show
that
concentrations
exhibit
high-frequency
cycles
12
24
h,
as
well
low-frequency
124
353
days,
while
also
modes
growth,
recession,
oscillation.
these
enables
reconstruction
with
a
mean
absolute
percentage
error
(MAPE)
only
0.6%.
Unlike
empirical
(EMD),
(KMD)
avoids
aliasing
provides
clearer
identification
key
compared
wavelet
analysis.
These
findings
underscore
effectiveness
KMD
analyzing
concentration,
offering
new
insights
understanding
other
phenomena.
Electronics,
Год журнала:
2024,
Номер
13(18), С. 3658 - 3658
Опубликована: Сен. 14, 2024
PM2.5
pollution
poses
an
important
threat
to
the
atmospheric
environment
and
human
health.
To
precisely
forecast
concentration,
this
study
presents
innovative
combined
model:
EMD-SE-GWO-VMD-ZCR-CNN-LSTM.
First,
empirical
mode
decomposition
(EMD)
is
used
decompose
PM2.5,
sample
entropy
(SE)
assess
subsequence
complexity.
Secondly,
hyperparameters
of
variational
(VMD)
are
optimized
by
Gray
Wolf
Optimization
(GWO)
algorithm,
complex
subsequences
decomposed
twice.
Next,
sequences
divided
into
high-frequency
low-frequency
parts
using
zero
crossing
rate
(ZCR);
predicted
a
convolutional
neural
network
(CNN),
long
short-term
memory
(LSTM).
Finally,
values
reconstructed
obtain
final
results.
The
experiment
was
conducted
based
on
data
1009A,
1010A,
1011A
from
three
air
quality
monitoring
stations
in
Beijing
area.
results
indicate
that
R2
value
designed
model
increased
2.63%,
0.59%,
1.88%
average
stations,
respectively,
compared
with
other
single
mixed
model,
which
verified
significant
advantages
proposed
model.