15.871-15.874  System Dynamics

We hope you are enjoying SIP and spring break. Just as a reminder for those of you staying in H2, group reshuffling is very common at this point. The remaining four assignments will likely be group assignments, so if your group lost members at the end of H1, please use the forum on the Stellar site to match up with other students. The remaining assignments require exactly 3 students per group (unless otherwise stated in the problem description). The TAs and the professor are not responsible for partner matching.

This message is for the students in Professor Goncalves' Tuesday/Thursday sections of System Dynamics (not the Sloan Fellows section).

So far, the class has done well on the first assignment. The TAs are mostly done so look for your assignments to start trickeling back. For future reference, MBA students should very clearly write "MBA" somewhere on the top of their first page so we know to return your homework to your folder. Unclaimed assignments will be outside Professor Goncalves' office. In the meantime, here are some common issues we would like to make clear:

B2.a. When members of the population are infected at the start of the simulation, we get "S" shaped growth (not just exponential).

B2.b. There is no mechanism to remove people from the stock of infected people in the simple SI model, so we will always infect our total population for allowable values of infectivity and contact frequency.

B2.d. It is crucial to see that a false interpretation of the system might be concluded if too narrow a time horion (such as 50 days) were used. One might conclude there is only exponential growth and not realize there is an effective carrying capacity.

C2.c. The singe most important element missing from our system dynamics model is the behavior modification that reduces infectivity (mask use, etc.) and reduces contact frequency (quarantine, etc.) during the epidemic. Also note that SARSDATA shows "reported" cases and many early infections went undiagnosed for some period.

Q1: What is the difference between 15.871 and 15.874?
A: 15.871 is the half term, 6 unit course. 15.874 is the full term, 12 unit course. 871 is good, 874 is better. The full term course is the prerequisite for further coursework in system dynamics and is needed for effective use of system dynamics in thesis and research work.

Q2:  Where do I hand in my assignment?
A: Assignments can be submitted in class, or to the system dynamics offices in E53-340 (the Dewey Library Building).

Q3: When are assignments due?
A: Assignments are due by the "close of business" (5:00 PM) on the assigned due date.  It's never a good idea to skip class so as to complete the assignment due that day.

Q4: How do I submit my assignment?
A: Please submit your assignment on paper. We cannot accept assignments submitted electronically. You can hand in the paper copy of your assignment in class on the day it is due, or by five PM on the day it is due (you can drop it off in E53-340 where there will be a box set out to collect assignments, or slide it under the professor's office door). For team assignments, be sure to list the names of your teammates on your assignment. Please retain a complete copy of your assignment as backup.

Q5: Where can I pick up my graded assignment?
A: Assignments will be returned to your mailfolders. If you are not a Sloan student or your assignment is not in your folder, your assignments can be found in the system dynamics office, E53-340.

Q6: For team assignments, how many people can be on a team?
A: Some assignments are individual; some are to be done in teams.  Each assignment will indicate whether it is individual or team based.  In team assignments, teams should be EXACTLY 3 people. Teams may consist of people from both sections (that is, your team can include people taking the morning and afternoon sections).