OMGT2087: Assessment 3
Case 1
Recycling is an important and complex activity in Country A. To enable timely operations,
the country is divided into 10 sectors and recycling operations are commenced
simultaneously in each sector. The recyclable garbage is collected from public bins, loaded
into trucks, and transported to recycling sites. Each site can accommodate different
amounts of recyclable garbage because of its available land size at the facility. The annual
capacities for five recycling sites are given in the table below (in megatonnes):
Each recycling site is installed with facilities that have different recycling efficiencies which
are summarised in the table below (in percentages):
The cost of collecting and transporting recyclable garbage primarily depends on the distance
between the sectors and the recycling sites. The following table summarises the distances
between each sector and each recycling site (in kilometres):
Using historical data, the country estimates the annual volume of the recyclable garbage for
each sector in the coming year shown in the table below (in megatonnes):
a. Formulate an multiple-objective linear programming (MOLP) model for this problem
in a Word file with a brief description of an equation, and implement the MOLP
model in an Excel spreadsheet.
b. Determine the optimal value for each objective in the problem.
c. Suppose the management considers maximising the amount of recycled garbage to
be three times as important as minimising the transportation cost. Formulate a GP
model to optimise both objectives simultaneously with a brief description of an
equation in a Word file, and implement the MOLP model in an Excel spreadsheet.
What do the results suggest?
(50 marks)
Case 2
Company B has twenty petrol stations across Melbourne. It is creating strategies to
consolidate warehouse operations so that there will be three warehouses that supply the
stations. The company plans to sell all its extant warehouses and build new, state-of-the-art
warehouses. Each warehouse can supply multiple stations; however, each station will be
supplied by a single warehouse. The location of each station is summarised in the table
