Week 3
Linear Programmming

Business

The start of the week email. No need to reread it here if you received it. It's just linked here in case anyone accidentally deleted it (it's happened before 🥺). Definitely let me know if you didn't receive it though so we can figure out why not.

Assignment 1 debriefing.

⦿ Monday. Linear Programming: First example

Example: Sleds and Toboggans Pencast 34:26|PDF
We begin with a simplified production problem: If we have some available resources in the form of time and material what should we manufacture to maximize profit?
Summary: Linear programming
Notes summarizing the procedure for solving a linear programming problem graphically.
Terminology: Linear programming
A glossary of terms I may use in the pencasts, exercises and assignment this week. Let me know if I missed any, and I'll add them.

Exercise Set

Exercise Set 3.1: Problems and Solutions.

⦿ Wednesday. Linear Programming: Two more examples

Example: Furniture manufacturing Pencast 24:28|PDF
Another manufacturing problem, this time with three production stages, so we end up with three constraints. Otherwise quite similar to the sleds and toboggans example.
Example: NASA nutrition Pencast 22:22|PDF
Linear progamming isn't only about factories and manufacturing. Here is a simplified nutritional problem, where the goal is to minimize the weight of food required to meet nutritional needs. This is important because it costs approximately $2,000US to put a pound of matter into orbit.

Exercise Set

Exercise Set 3.2: Problems and Solutions.

⦿ Friday. Linear Programming: The moose case study

Handout: Moose data [PDF]
This is most of the data we need to determine whether moose are maximizing energy or minimizing time. Take a look at the labels and values in the table to familiarize yourself with the problem. Which values are relevant to energy intake? Which ones to time taken?

There is an additional constraint that is not contained in the table: moose require sodium, which they can only get from aquatic macrophytes. The average moose needs 2.57g of sodium per day, and the density of sodium in the aquatic plants they eat is 0.003g/g.

Case Study: Moose foraging behaviour Pencast 38:09|PDF
Finally we have the tools to answer the question: Are foraging moose maximizing their energy intake, or minimizing their time spent foraging?

Our strategy will be to use linear programming to figure out how moose would behave if they were 1) maximizing, or 2) minimizing, and then to look at observational data to see which one their behaviour is closest to.

Supplementary resources

If you would like to consult traditional textbook-like materials, here are some for linear programming.

If you would like an interactive tutorial see Solving linear programming problems graphically ↗︎. If the text is very small (as it was for me) remember that you can have your browser scale it up by pressing Ctrl-+ or Command-+ repeatedly.

If you use any of these resources, please let me know how you found them!

Assignment

Assignment 3. Due by 1 pm Friday January 26.