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Time Series Forecasting
A Time Series
Is a sequential set of data points,
measured typically over
successive times.
Example
Time Series
Univariate
A time series
containing records
of a single variable.
Multivariate
A time series
containing records of
more than one variable.
Time Series
Continuous
Observations
measured at every
instance of time.
Discrete
Observations
measured at discrete
points of time.
Example
Components of a Time Series
◉ Trend.
◉ Cyclical variations.
◉ Seasonal variations.
◉ Irregular variations.
Trend
The general tendency of a time series to increase,
decrease or stagnate over a long period of time.
1
Example
Cyclical variation
Changes in the series, caused by circumstances,
which repeat in cycles.
2
Example
Seasonal variations
Fluctuations within a year during the season.
3
Example
Irregular or random variations
Caused by unpredictable influences, which are
not regular and also do not repeat in a particular
pattern.
4
Example
“Time Series Analysis
The procedure of fitting a
time series to a proper model.
“Concept of Stationarity
The statistical properties such as
mean and variance of a stationary
process do not depend upon time.
“
“
“Time series Stationarity is a
necessary condition for building a
time series model that is useful for
future forecasting.
Time Series Forecasting Models
◉ Stochastic Models.
◉ ANN-based Models.
◉ SVM-based Models.
Time series forecasting using Stochastic Models
◉ Auto-Regressive Model.
◉ Moving Average Model.
◉ ARMA Model.
◉ ARIMA Model.
◉ SARIMA Model.
Auto-Regressive ModelDITS
AR(p)
The feature value of a variable is assumed to be a
linear combination of p past observations.
Auto-Regressive ModelDITS
AR(1)
𝑋(𝑡) = 𝑎 ∗ 𝑋(𝑡 − 1) + 𝑤
Auto-Regressive ModelDITS
Linear Regression
ARMA Model
𝐴𝑅𝑀𝐴(𝑝, 𝑞)
Combination of Two Models
AR(p)
MA(q)
ARMA Model
Stationarity
ARIMA Model
Ordinary differencing
𝐴𝑅𝐼𝑀𝐴(𝑝, 𝑑, 𝑞)
ARIMA Model
𝑦𝑡
(1)
= 𝑦𝑡 − 𝑦𝑡−1
ARIMA Model
ARIMA Model
SARIMA Model
𝑆𝑒𝑎𝑠𝑜𝑛𝑎𝑙 𝐷𝑖𝑓𝑓𝑒𝑟𝑒𝑛𝑐𝑖𝑛𝑔
𝑦𝑡
(1)
= 𝑦𝑡 − 𝑦𝑡−𝑠
SARIMA Model
SARIMA Model
SARIMA Model
Time series forecasting using ANNs
◉ Universal functional approximators.
◉ Solve Nonlinear problems.
◉ Data Driven.
◉ Generalization.
◉ Tolerate noise in data.
Time series forecasting using ANNs
Time series forecasting using ANNs
Time series forecasting using SVM
◉ Function Approximation.
◉ Good Generalization.
◉ Optimal Separating Hyperplane.
◉ Regression Problems.
◉ Time Series Predication.
Time series forecasting using SVM
Comparison - Example
Comparison - Example
 Observed
 Stochastic
 ANN
 SVM
THANKS!
https://www.shamra.sy/academia/show/5b0c09997726f
Research URL

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