The Transportation Model

Learning Objective Describe the nature of a transportation problem Set up transportation problems in the general linear programming format Interpret computer solutions

Requirements for Transportation Model List of origins and each one’s capacity List of destinations and each one’s demand Unit cost of shipping Note: The DVD that accompanies this book contains a module that provides detailed instruction on the transportation model

Transportation Model Assumptions Items to be shipped are homogeneous Shipping cost per unit is the same Only one route between origin and destination

The Transportation Problem Figure 8S.1 D (demand) S (supply)

A Transportation Table Table 8S.1 Warehouse 4 7 1 100 12 3 8 200 10 16 5 150 450 80 90 120 160 A B C D 2 Factory Factory 1 can supply 100 units per period Total supply capacity per period Total demand per period Demand Warehouse B can use 90

Special Problems Unequal supply and demand Dummy: Imaginary number added equal to the difference between supply and demand when these are unequal Degeneracy: The condition of too few completed cells to allow all necessary paths to be constructed

Summary of Procedure Make certain that supply and demand are equal Develop an initial solution using intuitive, low-cost approach Check that completed cells = R+C-1 Evaluate each empty cell Repeat until all cells are zero or positive

Excel Template Figure 8S.2