# supply chain

ENMG 602 Homework Assignment 1

Problem 1:

Observations of the demand for a spare part stocked at a parts supply depot during the

calendar year 2012 were

Month Demand Month Demand

January 95 July 234

February 62 August 284

March 135 September 221

April 211 October 281

May 199 November 192

June 276 December 302

a. Determine the one-step-ahead forecasts for the demand for January 2013 using 3-, 6-, and 12-month moving averages.

b. Using a four-month moving average, determine the one-step-ahead forecasts for July through December 2012.

c. Compute MAD, MSE, MAPE for the forecasts obtained in b.

Problem 2:

Observed weekly sales of ball peen hammers at the town hardware store over a ten-week

period have been 13, 11, 26, 21, 32, 13, 21, 22, 30, and 26.

a. Suppose that five-week moving averages are used to forecast sales. Determine the one-step-ahead forecasts for weeks 6 through 10.

b. Suppose that exponential smoothing is used with a smoothing constant of α = 0.15. Find the exponential smoothing forecasts for weeks 6 through 10 (start the

forecasting process from week 1).

c. Based on the MAD, which forecast method is better?

Problem 3:

The sales of a tablet computer in a popular electronic store during the calendar year 2012

were

Month Demand Month Demand

January 103 July 199

February 119 August 208

March 131 September 221

April 149 October 237

May 172 November 252

June 184 December 268

a. Using 3-month simple moving average and exponential smoothing (with α = 0.10 and 0.20), determine the one-step-ahead forecasts for July 2012 through January

2013.

ENMG 602 Homework Assignment 1

b. Using 3-month double moving average (using base level and trend), determine the one-step-ahead forecasts for July 2012 through January 2013.

c. Compute MAD, MSE, and MAPE for the above forecasts. d. Based on the MAPE, which forecast method is the best?

Problem 4:

Compile a list of major system life-cycle activities. For each activity on the list, try to

find the related supply chain activities. Present your finding in a table with the system

life-cycle stage in the first column, system life-cycle activities in the second column and

the related supply chain activities in the third column.