Lecture F1 (2021-03-25): Chapter 8, Industry Dynamics - Oil Price and Global Oil Producers (Morecroft, 2015)

In this lecture, we review topics covered in Chapter 8 of Morecroft (2015), which is a case study of a system dynamics model of oil price trajectories meant to mimic a variety of periods of history while also helping in strategic scenario planning for the future. This particular model focuses on the effect of the OPEC oil cartel on price dynamics, including both the role of the swing producer in both setting prices and ensuring enforcement of quotas by other OPEC members.

Lecture E5 (2021-03-18): Assignment E5 – Creating Limited, Coupled Population Models

This lecture introduces a more significant homework assignment in SOS 212 that provides practice in building complex, multi-sector models in Vensim and Insight Maker. To aid in completing that assignment, the lecture also provides reminders of how to build equations for rates, how to implement lookup tables, how to use shadow variables (ghost primitives), and how to use the modulo (mod) operator to implement repeated, seasonal patterns.

Lecture E4 (2021-03-16): Chapter 6, The Dynamics of Growth and Diffusion (Morecroft, 2015)

This lecture covers content from Chapter 6 of Morecroft (2015), which focuses on the Bass model of product adoption (innovation diffusion) and related models that assist in decision making about marketing of new products within already crowded markets. Various connections are made between the Bass model (which is effectively a contagion model) and the SIR model covered in Lecture E3.

Lecture E3 (2021-03-11): Epidemic Dynamics

In this lecture, we apply system dynamics modeling to generate basic models of disease spread and scenario planning for intervention strategies in epidemiology and public health. In particular, we introduce the SIR model (and a few variations on it) and discuss the details of how it works and what the behavior over time curves mean. Topics related to current events, such as Ebola, COVID-19, and "flattening the curve", are discussed in relation to these models.

Lecture E2 (2021-03-09): Making Simulations More Realistic, Part 2 - Delays, Fixed and Smoothing

In this lecture, we describe how to implement delays in stock-and-flow diagrams in Vensim and Insight Maker. We focus on two specific types of delays -- fixed delays (as in transport delays) and smoothing/averaging delays (as in exponential decay). The lecture is motivated by a hypothetical exercise of modeling the ingestion process -- where food enters the mouth, travels down the esophagus (fixed delay), and then gets processed in the stomach (smoothing delay) as nutrients move into the bloodstream. Much of this lecture is devoted to building up intuition about what a "delay" parameter is in a smoothing delay -- this parameter captures the inertia (or sluggishness/resistance to change) of systems. That allows us to re-introduce the "time constant" again.

Lecture E1 (2021-03-04): Making Simulations More Realistic, Part 1 - Units, Sliders, and Lookup-Table Converters

In this lecture, we introduce several more advanced techniques in Vensim and Insight Maker that help to make simulations more realistic. We start with the formal use of units and unit conversions in models. We then introduce sliders, which allow for expedited exploration over parameter spaces in simulation models. We close with a demonstration of lookup tables, both for creating converters (specified with graphs or tables) from one variable to another as well as tools for introducing changes over time. Making use of Time in Vensim also requires introducing Shadow Variables.