Complexity Explorer Santa Few Institute

Introduction to Agent-Based Modeling

Lead instructor:

This course is no longer in session.

Unit 1: What is Agent-Based Modeling and Why Should You Use It?

Ananya Anandharaman
28 Jun 2024 6:41pm UTC
4
in Unit 1: What is Agent-Based Modeling and Why Should You Use It?

Hi! I was wondering if my project could be on applying ABM to astronomy somehow? A few topics I could think of were to understand star formation in nebulae or to model galaxy mergers. I tried looking for a few papers to derive some inspiration and get some direction, but I couldn't find any. If anyone has any ideas, please do let me know!

Isha
12 Jul 2024 4:53am UTC
in Unit 1: What is Agent-Based Modeling and Why Should You Use It?

Did you check Netlogo "Models Library"? (Hope I am not too late lol) As you know, ABM can be used/quite readily applied in cases where we can identify "agents", each following simple rules, whose interactions, we believe can explain the phenomenon we are trying to model. In astrophysics (astronomy?), let's say you want to model planetary/stellar/galactic dynamics, one of the rules could be the Gravitational interaction between the many "bodies" within your system (a rule similar to cohesion in bird flock example), Pressure/repulsive forces (in case you want to avoid a catastrophic collapse --you need to justify their inclusion though!), or some other kinematic rules that produces, say out-of plane (3D) effects...(a few ideas I could think of)

Ananya Anandharaman
15 Jul 2024 4:34pm UTC
in Unit 1: What is Agent-Based Modeling and Why Should You Use It?

Hey! thank you for replying! I hadn't thought of using the bird flock example as reference, for the google form, i submitted the ants model as that was kind of similar? As for the assignment, I've made it 2D so far. How would you suggest I explore 3D effects?

Isha
22 Jul 2024 2:45pm UTC
in Unit 1: What is Agent-Based Modeling and Why Should You Use It?

It depends on how you want to model. For some problems/phenomenon (say bird flock, again ..or planets!) you can view 3D as an extension to 2D where we have the same rules, but now there's an extra dimension for agents to play around (valid, if the world looks the same everywhere....homogeneous and isotropic). You can do the same with the ants model aswell (if you find it appropriate), but you may also think about introducing additional rules (added complexity) for how the ants can now dig into the 'soil' (in the process, forming hills above the surface), and navigate underground between neighboring foraging locations. It's really up to you!

To get you started, you may find the following videos helpful!?

https://www.youtube.com/watch?v=FOgfncOtkYU
https://www.youtube.com/watch?v=k443Wmvgktw

Best wishes!

P.S: If you are interested..there's better example for the gravity problem (check 'N-Bodies' in Netlogo models library)

Isha
22 Jul 2024 3:03pm UTC
in Unit 1: What is Agent-Based Modeling and Why Should You Use It?

Ignore the second link...(I pasted a wrong one!). Check the one below
https://www.youtube.com/watch?v=vG-QZOTc5_Q

Pierre Vella-Zarb
26 Jun 2024 2:29am UTC
2
in Unit 1: What is Agent-Based Modeling and Why Should You Use It?

Bill spoke of a Participant Poll early on in Unit 1. Where can this be found?

Scott
26 Jun 2024 3:11am UTC
in Unit 1: What is Agent-Based Modeling and Why Should You Use It?

The text underneath the video player says it has been removed

Pierre Vella-Zarb
28 Jun 2024 9:36pm UTC
in Unit 1: What is Agent-Based Modeling and Why Should You Use It?

Thank you Scott

Mustafa Ali Saba
22 Jun 2024 6:03am UTC
2
in Unit 1: What is Agent-Based Modeling and Why Should You Use It?

For instance, in the traffic jam model, phase transition would be when you increase the number of cars at a certain quantity which cause the jam?

Does this idea of phase transition is a characteristic of a complex system?

thanks.

Sani Gildenhuys
22 Jun 2024 1:14pm UTC
in Unit 1: What is Agent-Based Modeling and Why Should You Use It?

I think phase transitions is indeed characteristic of a complex system, but there is no guarantee that the model will actually show the phase transition. We'll have to play around with the inputs to observe the emergent patterns.

Mustafa Ali Saba
22 Jun 2024 8:01pm UTC
in Unit 1: What is Agent-Based Modeling and Why Should You Use It?

Thank you Sani Gildenhuys for this intuition, it is very helpful :)

alberto
22 Jun 2024 11:17am UTC
in Unit 1: What is Agent-Based Modeling and Why Should You Use It?

"EXpected a number here, rather than a list or block"

The code has an error when opening the model
Can somebody help me ?

David Ryan
19 Jun 2024 6:17pm UTC
in Unit 1: What is Agent-Based Modeling and Why Should You Use It?

For example the classic IBM 'General Purpose Simulation System' has discrete 'entities' which are agent like (and have their own properties and logic) and 'activities' which entities undertake, it may be that the activity requires, say two 'nurse' entities and one 'doctor' entity to deal with a 'patient' entity using the process 'surgery'.

Are there models built in GPSS (which has been around since the 1960s) which are informative of ABS approaches or problems?

Alison Link
18 Jun 2024 9:28pm UTC
in Unit 1: What is Agent-Based Modeling and Why Should You Use It?

In the "Spatial Models" video, Professor Rand mentions a model that a student was doing that involves a pretty complex transportation policy analysis for Chicago. I didn't see a citation for this work--is there a way to find her dissertation or related article(s) somewhere? This relates to my work, so I'd love to look into this deeper!

Thomas Koundakjian
12 Jun 2024 9:40pm UTC
4
in Unit 1: What is Agent-Based Modeling and Why Should You Use It?

My understanding of the difference between "Leverage Point" and "Tipping Point" (based on the videos) is that a Leverage Point is a factor in a model whose value (or a change in that value) can lead to dramatically different outcomes and a Tipping Point is the specific value of the factor at which you observe a phase shift. So, for example, in the Fire model, density of the forest is a Leverage Point and the Tipping Point is in the range of 58% to 62% because at some point in this range of values the outcome goes from the fire dying out to the fire burning a substantial part of the forest.

I was wondering if others understood these two terms in the way I describe or if people understood them differently.

Jennifer Joyalle
13 Jun 2024 6:15am UTC
in Unit 1: What is Agent-Based Modeling and Why Should You Use It?

Hi Thomas, I agree with your description. My understanding is that a leverage point assumes that a system can be controlled (believing that the original configuration can be maintained, yet controlled) - think of cybernetics or a thermostat. A tipping point is a state flip where the system cannot reorganize into its original configuration.

David Piorunek
18 Jun 2024 3:16pm UTC
in Unit 1: What is Agent-Based Modeling and Why Should You Use It?

I agree with your description. Here you can find a part of Donella Meadows' book on Systems Thinking that deals with "leverage points". A more general explanation. As Jennifer mentions the "control" which Meadows deals with too, even calling it a "lore". E.g., temperature/heat flow control in a house is a rather simple task, compared to more complex challenges of maintaining meta-stable equilibria of the climate system, ecosystems, markets, etc. Maybe the both of you find it interesting, I can definitely recommend her book "Thinking in Systems".

David Piorunek
18 Jun 2024 3:16pm UTC
in Unit 1: What is Agent-Based Modeling and Why Should You Use It?

https://donellameadows.org/archives/leverage-points-places-to-intervene-in-a-system/

Victor Hugo de Holanda Cavalcanti
18 Jun 2024 8:41pm UTC
in Unit 1: What is Agent-Based Modeling and Why Should You Use It?

I don't understand. What is a beverage point? Just drinking... ops, kidding.

Luis García Valverde
15 Jun 2024 11:29pm UTC
1
in Unit 1: What is Agent-Based Modeling and Why Should You Use It?

Hello!

I have worked in the past with Cellular Automata (CA) and now that I'm learning about Agent Based Models I struggle to find the difference. For example, in the fire model in NetLogo, I'm not sure if it is a CA, an ABM or could be both.

Thanks!

Paul Cousin
16 Jun 2024 10:12am UTC
in Unit 1: What is Agent-Based Modeling and Why Should You Use It?

The Fire model is actually cellular automaton. You can see CA as ABMs with agents fixed in place on a lattice and only able to interact with their neighbors. However, ABM agents don't have to be limited in this way. They can move around and talk to different agents at different times for example, like in the sheep and wolves model in Uri Wilensky's introduction, which is definitely not a CA.

Tingting Zhao
10 Jun 2024 11:48am UTC
in Unit 1: What is Agent-Based Modeling and Why Should You Use It?

Deduction is not reasoning from first principles to general theory. Rather, it is reasoning from general principles to a specific conclusion.

For example:
General Principle: All humans are mortal.
Specific Case: Socrates is a human.
Conclusion: Therefore, Socrates is mortal.

Subforums