Lecture D-E (2021-02-23): Midterm Review

This lecture serves as a review of the pre-midterm material in SOS 212 (Systems, Dynamics, and Sustainability) in the Spring 2021 semester at Arizona State University. It reviews basic topics on modeling philosophy, causal loop diagrams, systems archetypes, and basic stock-and-flow diagram/simulation concepts.

Lecture D4 (2021-02-18): Chapter 3, Modelling Dynamic Systems (Morecroft, 2015)

In this lecture, we start with a brief tutorial of simulating simple stock-and-flow diagrams (Systems Dynamics Models) in Vensim and Insight Maker. We then discuss Chapter 3 (Modelling Dynamic Systems) from Morecroft (2015), which introduces building and simulating dynamical systems models.

Lecture D3 (2021-02-16): Stock and Flow Diagrams in Vensim and Insight Maker

This lecture continues our introduction to stock-and-flow diagrams, moving from implementation in spreadsheets to implementation in special-purpose simulation software such as Vensim and Insight Maker. We also cover the motivation behind common flow expressions for population-growth systems and systems that fill or empty over time (which allows us to define "time constant").

Lecture D2 (2021-02-11): Introduction to Numerical Simulation of Dynamical Systems, Part 2

This lecture continues where the previous one left off in the introduction of numerical simulation of dynamical systems. We spend most of the lecture working through the bacterial growth example and adding a death process. This allows us to better highlight the ways that stocks and different flows can interact. We conclude with a challenge to simulate a toilet-tank example in a spreadsheet, which is a negative feedback loop that very different "flow" formulas but otherwise is simulated in a very similar way to the bacterial growth case.

Lecture D1 (2021-02-09) - Introduction to Numerical Simulation of Dynamical Systems, Part 1

In this lecture, we more formally introduce the dynamical processes that drive system behaviors over time. To motivate how these dynamical processes can be simulated, we consider two different ways to calculate compound interest in a bank. The second way, which involves calculating how much interest is generated each year, is identical to how we numerically integrate dynamical processes captured as stock and flow diagrams. We discuss a simple bacterial growth modeling problem as an example.

Lecture C2 (2021-02-04): "Applying Systems Archetypes" (Kim and Lannon, 1997)

In this lecture, we review the article by Kim and Lannon (1997) on "Applying Systems Archetypes." This article introduces System Archetypes, a set of combinations of feedback loops that common occur in systems and are associated with a set of problems, possible solutions, and likely behaviors over time (BOT). This article portrays the System Archetypes as tools that can be used in one of four different ways -- as structural pattern templates, as lenses for highlighting subtle but important potential aspects of problems, as dynamic theories for understanding and invention, and as tools for predicting future behavior based only on the internal components of a system. We explore these four different ways of applying the archetypes and tie them in to the scientific method we practice within Sustainability Science which is often assisted through the use of computer simulation modeling.

Lecture C1 (2021-02-02): Feedback Systems Thinking with CLDs

In this lecture, we introduce ways to build up more complex thinking using Causal Loop Diagrams by introducing fundamental modes of dynamic behavior. These fundamental modes can generate aspects of many common behaviors over time just through the combination of a few patterns of feedback loops and delays. This lecture helps motivate the more complex System Archetypes that will be introduced in the next lecture.