Demand for an item for the last six periods is: 11 13 Period Actual demand t -3 10 -2 -1 0 14 1 17 2 18 5 marks a) Initialize the exponential smoothing model with correction for trend using historical values for periods -3, -2, -1 and 0. Calculate an ex-post forecast for period 1 as of end of period 0. 00 6 marks b) Apply (i.e., walk) the model through periods 1 and 2. Calculate at the end of period 1, forecast error for period 1 and the forecast for period 2. Similarly, at the end of period 2, calculate forecast error for period 2 and forecasts for periods 3, 4, 5, 6, 7 and 8 (round your forecast to the nearest digit). Use uw=.3 and Buw = .5. Finally, calculate o, (i.e., the sandard deviation of one-period-ahead-forecast error). - c) If lead-time is 2 periods and PA=.95, what should be the safety stock for this item? Assume that all releases and receipts can occur only at the beginning of the periods. (Note k=1.645 for P1= 95). 7 marks d) Suppose for the item under consideration in parts a), b) and c): Present time= end of period 2 Present on hand = 54 units Q = Periodic order quantity with T, of 3 Plan the next replenishment cycle (i.e., show just one replenishment cycle) for the item. You may round forecasts to the nearest integers and renumber time periods 2, 3, 4, 5, 6, 7, 8 as periods 0,1,2,3,4,5,6, respectively. (The present time then will be end of period 0 rather than end of period 2). 2 Demand for an item for the last six periods is: 11 13 Period Actual demand t -3 10 -2 -1 0 14 1 17 2 18 5 marks a) Initialize the exponential smoothing model with correction for trend using historical values for periods -3, -2, -1 and 0. Calculate an ex-post forecast for period 1 as of end of period 0. 00 6 marks b) Apply (i.e., walk) the model through periods 1 and 2. Calculate at the end of period 1, forecast error for period 1 and the forecast for period 2. Similarly, at the end of period 2, calculate forecast error for period 2 and forecasts for periods 3, 4, 5, 6, 7 and 8 (round your forecast to the nearest digit). Use uw=.3 and Buw = .5. Finally, calculate o, (i.e., the sandard deviation of one-period-ahead-forecast error). - c) If lead-time is 2 periods and PA=.95, what should be the safety stock for this item? Assume that all releases and receipts can occur only at the beginning of the periods. (Note k=1.645 for P1= 95). 7 marks d) Suppose for the item under consideration in parts a), b) and c): Present time= end of period 2 Present on hand = 54 units Q = Periodic order quantity with T, of 3 Plan the next replenishment cycle (i.e., show just one replenishment cycle) for the item. You may round forecasts to the nearest integers and renumber time periods 2, 3, 4, 5, 6, 7, 8 as periods 0,1,2,3,4,5,6, respectively. (The present time then will be end of period 0 rather than end of period 2). 2
