User Manual

•
c = exp
1
n
S
1
S
3
- S
2
2
S
1
+ S
3
- 2S
2
•
a = exp
(b - 1)(S
2
- S
1
)
b(b
n
- 1)
2
•
Where S
1
, S
2
, and S
3
are:
•
S
1
= ln y
i
= n ln c + b (ln a)
b
n
- 1
b - 1
•
S
2
= ln y
i
= n ln c + b
n + 1
(ln a)
b
n
- 1
b - 1
•
S
3
= ln y
i
= n ln c + b
2n + 1
(ln a)
b
n
- 1
b - 1
•
a, b and c are determined by solving the three equations above simultaneously.
Forecasting With Exponential Smoothing
•
a = smoothing constant (0 < a < 1)
•
X
t
= actual current period usage
•
Smoothed average S
t
=
α
X
t
+ (1 -
α
)S
t - 1
•
Change, C
t
= S
t
- S
t - 1
•
Trend, T
t
=
α
C
t
+ (1 -
α
)T
t - 1
•
Current period expected usage, D
t
= S
t
+
(1 - a)
α
T
t
•