E N D
1. Chapter 7Demand Forecastingin a Supply Chain
2. Data With Trend Trend and Seasonality: Adaptive -2
3. Trend Adjusted Exponential Smoothing: Holts Model Appropriate when there is a trend in the systematic component of demand. Trend and Seasonality: Adaptive -3
4. General Steps in adaptive Forecasting 0- Initialize: Compute initial estimates of level, L0, trend ,T0 using linear regression on the original set of data; L0= b0 , T0 = b1. No need to remove seasonality, because there is no seasonality.
1- Forecast: Forecast demand for period t+1 using the general equation, Ft+1 = Lt+Tt
2- Modify estimates: Modify the estimates of level, Lt+1 and trend, Tt+1.
Repeat steps 1, 2, and 3 for each subsequent period Trend and Seasonality: Adaptive -4
5. Trend-Corrected Exponential Smoothing (Holts Model) In period t, the forecast for future periods is expressed as follows Trend and Seasonality: Adaptive -5
6. Holts Model Example (continued)
7. Holts Model Example (continued) Forecast for period 1:
F1 = L0 + T0 = 12015 + 1549 = 13564
Observed demand for period 1 = D1 = 8000
E1 = F1 - D1 = 13564 - 8000 = 5564
Assume a = 0.1, b = 0.2
L1 = aD1 + (1-a)(L0+T0) = (0.1)(8000) + (0.9)(13564) = 13008
T1 = b(L1 - L0) + (1-b)T0 = (0.2)(13008 - 12015) + (0.8)(1549)
= 1438
F2 = L1 + T1 = 13008 + 1438 = 14446 Trend and Seasonality: Adaptive -7
8. Holts Model Example (continued) Trend and Seasonality: Adaptive -8
9. Double Exponential Smoothing: a = 0.2 and b = 0.3 Trend and Seasonality: Adaptive -9
10. Double Exponential Smoothing: a = 0.2 and b = 0.3 Trend and Seasonality: Adaptive -10
11. Varying Trend Example Trend and Seasonality: Adaptive -11
12. Varying Trend Example Trend and Seasonality: Adaptive -12
13. Double Exponential Smoothing Trend and Seasonality: Adaptive -13