Tuesday, October 07, 2008

Agent-based models in Second Life

Just a quick update on our work with agent-based modelling (ABM) in Second Life. Below are a series of models that we have created in Second Life as proofs of concept and a test for how well Second Life copes with different types of agent-based models. We have created three models which we demonstrate below.

Our first model is chosen Conway’s Game of Life. The movie below details its inner workings:


Game of Life from Andrew Crooks.


The sound track is 'A Lonely Place without You' by New Inception.

Our second model is Schelling’s (1978) Segregation model. Where through mild tastes and preferences to locate with like groups segregation arises. The above models were chosen as they highlight how classical automata styles of models which have inspired a generation of modellers can be created and explored in Second Life.


Schelling's Segregation Model from Andrew Crooks.


Our third model is a prototype pedestrian evacuation model which is more complex than the previous two and highlights at the variety of models that can be potentially created in Second Life. We first started off with agents randomly walking around a room avoiding each other and walls as the movie below demonstrates.


Random Walking from Andrew Crooks.


Then we took the model further were agents exit the building once an alarm is sounded. Within this model we have designed three different room configurations, from a simple square room, a more complex room with internal walls and tables as obstacles, and a multi-floor building were the agents have to walk down the stairs towards the exit (all of which are shown below). From these three scenarios one can explore how room configurations, obstacles and density of surrounding pedestrians impact on pedestrian egress.

Pedestrian Evacuation Model: simple layout from Andrew Crooks .

To further help understand we record the paths the pedestrians walk when exiting the building. The movie below shows the paths travelled of pedestrians exiting the simple room from the movie above.



Pedestrian Evacuation Model: simple layout-trace movie from Andrew Crooks on Vimeo.



Pedestrian Evacuation Model: complex layout from Andrew Crooks.



Pedestrian Evacuation Model: Multi-floor layout from Andrew Crooks.


All the models where written using the Linden Scripting Language (see Rymaszewski et al., 2007) rather than following a loose coupling approach. Further details (including code and model descriptions) and movies of simulations from the models can be found here. If you use Second Life, you can visit our agent street (The SLURL to go there directly is here). In agent street you can experiment with the models and there are also vending machines which allow you to download the model.



Any thoughts or comments or most welcome.

2 comments:

LimeyChomper said...

Hi there

I am trying to teleport here, but it all seems to have disappeared. I can't find the models - have they all been removed?

Andrew Crooks said...

Sorry you cant get to Agent street. We had to move it but its still there, just a bit higher. If you teleport to Second Nature 2 Island,fly up into the clouds you will see Agent Street. Hope this helps.