MODULE 6 - MANSCI

• Polytechnic University of the Phils. College of Business Administration, Human Resource Management, Prof. Marifel i. javier
• Transportation model


  Formulated for a class of problems where a product is transported from several sources to several destinations at the minimum possible cost, each source can supply a fixed number of units and each destination has a fixed demand
• In Operations Management this is what we called "LOGISTICS"
• Transportation problem


  Items are allocated from sources to destinations at a minimum cost
• Example of transportation problem


  • Determine how many tons of wheat to transport from each grain elevator to each mill on a monthly basis to minimize the total cost of transportation
• Constraints in transportation model

  1. Represent demand at each mill

  2. Represent supply of each elevator

  3. Represent tons of wheat transported from Kansas City to all three mills
• Balanced transportation model is when supply = demand
• Unbalanced transportation model is when supply exceeds demand or vice-versa
• Some routes in transportation model may be prohibited
• Computer solution with QM for Windows


  Provides optimal solution showing shipments in each cell and total cost
• QM for Windows will not identify alternate solutions
• Sensitivity analysis


  Can be performed by changing model size or parameters
• Transshipment model


  An extension of transportation model with intermediate transshipment points between sources and destinations
• Transshipment problem


  • Items may be transported from sources through transshipment points on to destinations
  • From one transshipment point to another
  • From one source to another
  • From one destination to another
  • Directly from sources to destinations
• Transshipment model formulation


  1. Develop supply-and-demand constraints for farms, mills, and transshipment points (grain elevators)

  2. Principle that amount shipped in must equal amount shipped out at each transshipment point
• Transshipment model can be solved using Excel or QM for Windows
• Assignment model


  A special form of LP similar to transportation model, but supply at each source and demand at each destination are each limited to one unit
• Example of assignment model

  • The Atlantic Coast Conference (ACC)
• Unbalanced assignment model exists when supply exceeds demand or demand exceeds supply
• Example of unbalanced assignment model


  • A concrete company transports concrete from three plants to three construction sites