Download presentation

Presentation is loading. Please wait.

Published byRyley Nabb Modified about 1 year ago

1
Lecture 15: Transportation and other Networks AGEC 352 Spring 2012 – March 21 R. Keeney

2
Network Models Entry nodes, exit nodes, transition nodes Classic example: ◦ Production: Enter into the network ◦ Wholesale/Warehouse: Waypoint between production and sale ◦ Retail: Exit the network (final demand)

3
Transportation Example Entry nodes ◦ Jacksonville and New Orleans Exit nodes ◦ New York City, Chicago Transition nodes ◦ Atlanta, Dallas

4
Diagrammatic Example Jacksonville New Orleans Atlanta Dallas New York City Chicago Origin Points Waypoints Origin Points End Points

5
Diagrammatic Example: Additional Routes to Waypoint Jacksonville New Orleans Atlanta Dallas New York City Chicago

6
Diagrammatic Example: Additional Routes to Retail Jacksonville New Orleans Atlanta Dallas New York City Chicago

7
Diagrammatic Example: Supply and Demand Numbers Jacksonville New Orleans Atlanta Dallas New York City Chicago 100 Units 200 Units 50 Units 70 Units

8
Diagrammatic Example: Additional Retail Options Jacksonville New Orleans Atlanta Dallas New York City Chicago 100 Units 200 Units 120 Units 60 Units 50 Units 70 Units

9
Two nodes are destinations and sources How do we deal with this? Recall the balance equation we saw earlier in the semester for a product like corn ◦ Corn bushels produced (S) >= corn bushels marketed (M) ◦ S – M >= 0 ◦ Assume we wanted to store 500 bushels ◦ S – M >= 500

10
Balance equation Atlanta ◦ S = Quantity of items entering from Jacksonville and New Orleans ◦ M = Quantity of items shipped to New York and Chicago ◦ S – M >= 70 Dallas?

11
Diagrammatic Example: Direct Routes Jacksonville New Orleans Atlanta Dallas New York City Chicago 100 Units 200 Units 120 Units 60 Units 50 Units 70 Units

12
Diagrammatic Example: Cost Information Jacksonville New Orleans Atlanta Dallas New York City Chicago 100 Units 200 Units 120 Units 60 Units 50 Units 70 Units $150 $75 $125 $150 $100

13
Diagrammatic Example: Cost Information Jacksonville New Orleans Atlanta Dallas New York City Chicago 100 Units 200 Units 120 Units 60 Units 50 Units 70 Units $150 $75 $125 $150 $100

14
How to model in Excel? Cost Matrix From/ToAtlDalNYChi Jax N.O Atl Dal-- 100

15
Constraints We can still use the sums at the end of rows and columns, but it will be easier to organize them in a separate location since some constraints will require both the row and column sum to calculate We will need to force some decision variables to be zero (unavailable routes) ◦ We can do this by constraining them to zero ◦ Or, omitting from the decision variable matrix

16
Notes If you constrain the routes to zero, there will be meaningless sensitivity information ◦ Force a route to equal zero and there is a shadow price but it depends on the unit cost of using that route ◦ If you had a credible estimate of the unit cost of transportation the shadow price might be useful

17
Comments We’ll see a couple of different applications of network models that work just like transportation next week Assignments and Inventory Schedules ◦ Source = people; Destination = jobs ◦ Source = supply today; Destination = demand in the future Any network can be modeled, you just can’t expect them all to be cookie cutter versions…

18
Medley Swimming (U.S. 2008) Swimmer/ Stroke BackBreastB-flyFree Peirsol Hansen Phelps Lezak

19
Olympic Swimming Michael Phelps is the world’s greatest swimmer If you need to win a race, you pick him If you need to win a relay race, you pick him but where do you use him? Medley swimming ◦ Backstroke, Breaststroke, Butterfly, Freestyle

20
Quiz on Monday Another Transportation Case with Waypoint nodes (serve as source and destination)

Similar presentations

© 2017 SlidePlayer.com Inc.

All rights reserved.

Ads by Google