Practical Assignment
Problem 1

South West Electronics (SWE) Ltd produces electronic security devices for buildings. The demands history is shown in table-1. You are required by the executive to write a report on the future demand of the product, which should provide the following information.

Table-1.1 Sales History

Sales 2015 2016 2017 2018 2019
Jan 3,000 3,000 4,000 5,000 5,000
Feb 3,000 4,000 5,000 4,000 3,000
Mar 4,000 4,000 6,000 5,000 4,000
Apr 4,000 5,000 4,000 3,000 3,000
May 5,000 5,000 4,000 6,000 7,000
Jun 6,000 8,000 6,000 7,000 6,000
Jul 7,000 5,000 7,000 10,000 8,000
Aug 7,000 8,000 10,000 14,000 11,000
Sep 10,000 12,000 15,000 16,000 20,000
Oct 12,000 13,000 15,000 17,000 20,000
Nov 14,000 16,000 18,000 20,000 22,000
Dec 8,000 10,000 9,000 12,000 8,000
Total 83,000 93,000 103,000 119,000 117,000

Using the historical data shown in Table-1.1,

(a). Recommend an appropriate demand forecasting method for SWE. Please make an explanation of why you choose this method. (15 marks)

(b). Using the method that you recommend above, develop your forecast for the monthly demand of SWE in 2020 (smoothing constants can be set to 0.1 if needed). Please specify how you build your forecasting model with necessary in-progress calculation included and conclude your forecasting results. (35 marks)

Problem 2

Table-2.1 Costs and other information
Item Cost
Material cost £15/unit
Inventory holding cost £0.3/unit/month
Marginal cost of stockout/backlog £25/unit
Hiring and training cost £1000/worker
Layoff cost £2000/worker
Labour hours required 3 hours/unit
Regular time cost £6/hour
Overtime cost £12/ hour
Cost of subcontracting £38/unit
Starting workforce size 100
Overtime limitation per worker 10 hours/month
Initial inventory 1000 units
End inventory 1000 units
Shift 1
Hours per day 8
Days per month 4 weeks * 5 days
Selling price £40/unit

Table-2.2 Demand Forecast of 2020
Forecast Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2020 5,000 3,000 4,000 3,000 7,000 6,000 8,000 11,000 20,000 20,000 22,000 8,000

The operational data of costs and other information of South West Electronics (SWE) Ltd are provided in table-2.1. Using the demand forecast given in table-2.2, make an aggregate production plan of 2020 for SWE. Please specify how you build your planning model with necessary calculation progress included and conclude your forecasting results. (50 marks)