Difference between revisions of "Forest Fire Tutorial"
imported>Andri |
imported>Andri |
||
(6 intermediate revisions by the same user not shown) | |||
Line 44: | Line 44: | ||
This is a good time to save the world! | This is a good time to save the world! | ||
− | == | + | == Programming the Tree == |
We need to program the Tree agent to catch on fire if it's next to a burning tree and burn completely when the fire dies out. Select the Tree agent in the Agents list and its behavior will appear in the Behavior view. Create two rules for the tree:, one to start the fire if it's a healthy tree with a certain probability, and one to stop it when the fire dies out with a certain probability: | We need to program the Tree agent to catch on fire if it's next to a burning tree and burn completely when the fire dies out. Select the Tree agent in the Agents list and its behavior will appear in the Behavior view. Create two rules for the tree:, one to start the fire if it's a healthy tree with a certain probability, and one to stop it when the fire dies out with a certain probability: | ||
Line 62: | Line 62: | ||
</tr> | </tr> | ||
</table> | </table> | ||
− | |||
Now try out your simulation by running it. Depending on the density of the forest you created, the fire spreads widely or dies out quickly. | Now try out your simulation by running it. Depending on the density of the forest you created, the fire spreads widely or dies out quickly. | ||
'''''But notice something''''': if you reset your world to its original saved state and hit the Step button to run one cycle of the simulation you will get something like this: | '''''But notice something''''': if you reset your world to its original saved state and hit the Step button to run one cycle of the simulation you will get something like this: | ||
− | |||
<table width="900"> | <table width="900"> | ||
Line 82: | Line 80: | ||
</tr> | </tr> | ||
</table> | </table> | ||
− | |||
'''How can we fix this?''' We need to coordinate the behavior of the tree so that within the same simulation cycle, all the trees have a chance to determine if they should be burning first, and then actually perform the burning actions. For that, we can use a Controller agent to synchronize the tree behavior (make it parallel). | '''How can we fix this?''' We need to coordinate the behavior of the tree so that within the same simulation cycle, all the trees have a chance to determine if they should be burning first, and then actually perform the burning actions. For that, we can use a Controller agent to synchronize the tree behavior (make it parallel). | ||
− | == Programming the Controller to synchronize/parallelize tree burning == | + | == Programming the Controller & Tree to synchronize/parallelize tree burning == |
<table width="900"> | <table width="900"> | ||
<tr> | <tr> | ||
Line 93: | Line 90: | ||
<table width="400"> | <table width="400"> | ||
<tr> | <tr> | ||
− | <td height="150">To synchronize the actions of trees, the | + | <td height="150">To synchronize the actions of trees, the '''Controller''' broadcasts to all trees a PERCEIVE message to determine if they are supposed to be burning, followed by an ACT message to actually start burning or have the fire die out. |
</td> | </td> | ||
</tr> | </tr> | ||
Line 100: | Line 97: | ||
</tr> | </tr> | ||
</table> | </table> | ||
− | |||
<table width="900"> | <table width="900"> | ||
<tr> | <tr> | ||
− | <td width="500">[[Image:Tree behavior.png]]</td> | + | <td width="500">[[Image:Tree behavior.png|500px]]</td> |
<td> | <td> | ||
<table width="400"> | <table width="400"> | ||
<tr> | <tr> | ||
− | <td align="top" height="200">The PERCEIVE method of the | + | <td align="top" height="150">The tree does not do anything in its While-Running method. |
+ | </td> | ||
+ | </tr> | ||
+ | <tr> | ||
+ | <td align="top" height="200">The PERCEIVE method of the '''Tree''' determines whether a healthy tree should start burning - it does so if the healthy tree is next to at least one burning tree, with a certain probability (defined by the simulation property Fire_Spreading_Probability in this case). Please note that the PERCEIVE method does not actually set the tree on fire by turning it into a burning tree, but sets a variable/flag to indicate that the tree should be burning. This way, all the trees get a chance to determine whether they should be burning in parallel, avoiding the issue encountered in the previous section. | ||
</td> | </td> | ||
</tr> | </tr> | ||
Line 126: | Line 126: | ||
</tr> | </tr> | ||
</table> | </table> | ||
− | |||
Now try running your simulation again. Stepping through your fire simulation should look like this: | Now try running your simulation again. Stepping through your fire simulation should look like this: | ||
<youtube>bbAA5qWKX50</youtube> | <youtube>bbAA5qWKX50</youtube> | ||
− | |||
== Regenerating the forest with a certain density == | == Regenerating the forest with a certain density == | ||
− | |||
<table width="900"> | <table width="900"> | ||
<tr> | <tr> | ||
− | <td width="500">[[Image:Controller | + | <td width="500">[[Image:Controller mouse click.png|500px]]</td> |
<td> | <td> | ||
<table width="400"> | <table width="400"> | ||
Line 148: | Line 145: | ||
</tr> | </tr> | ||
</table> | </table> | ||
− | |||
− | |||
<table width="900"> | <table width="900"> | ||
Line 164: | Line 159: | ||
</tr> | </tr> | ||
</table> | </table> | ||
− | |||
== Simulation Properties == | == Simulation Properties == | ||
Line 194: | Line 188: | ||
== Updating the world to include Controller and Start_Here agents == | == Updating the world to include Controller and Start_Here agents == | ||
− | + | Add a controller agent and a Start_Here agent to your world, save your world, and you are ready to start data collection for the [[Sample_Forest_Fire_Lesson_Plans | Sampling and Bivariate Data Analysis unit]]. | |
− | Add a controller agent and a Start_Here agent to your world | ||
− | |||
− |
Latest revision as of 23:44, 24 August 2011
Contents
- 1 Introduction
- 2 Creating the Project
- 3 Creating Agents
- 4 Creating a Forest
- 5 Programming the Tree
- 6 Programming the Controller & Tree to synchronize/parallelize tree burning
- 7 Regenerating the forest with a certain density
- 8 Simulation Properties
- 9 Updating the world to include Controller and Start_Here agents
Introduction
The forest fire simulation built with this tutorial enables you to explore how forest fires unravel by letting you set fires to virtual forests with different tree densities. This simulation can them be used for data collection and analysis in math units.
Creating the Project
Launch AgentCubes and create a new project (choose the location and name of your project).
Creating Agents
The simulation has a Tree agent, a Ground agent, a Controller agent, and a Start Here agent.
Creating a Forest
If you haven't created a new world, use the + button at the top of the project window to create one. Please note that later on we will be generating the forest automatically, but for now let's do this manually: Select your Ground agent in the Agents list and using the Volume Insert tool, lay out a layer of Ground agents in the background of your world. Then select your healthy Tree agent shape and using the Draw tool place a few on the Ground. Place one Tree_Burning, which will start the fire, somewhere in the middle of the world to create a forest like the one shown below.
This is a good time to save the world!
Programming the Tree
We need to program the Tree agent to catch on fire if it's next to a burning tree and burn completely when the fire dies out. Select the Tree agent in the Agents list and its behavior will appear in the Behavior view. Create two rules for the tree:, one to start the fire if it's a healthy tree with a certain probability, and one to stop it when the fire dies out with a certain probability:
|
Now try out your simulation by running it. Depending on the density of the forest you created, the fire spreads widely or dies out quickly.
But notice something: if you reset your world to its original saved state and hit the Step button to run one cycle of the simulation you will get something like this:
|
How can we fix this? We need to coordinate the behavior of the tree so that within the same simulation cycle, all the trees have a chance to determine if they should be burning first, and then actually perform the burning actions. For that, we can use a Controller agent to synchronize the tree behavior (make it parallel).
Programming the Controller & Tree to synchronize/parallelize tree burning
|
|
Now try running your simulation again. Stepping through your fire simulation should look like this:
<youtube>bbAA5qWKX50</youtube>
Regenerating the forest with a certain density
|
|
Simulation Properties
Running your simulation will create the simulation properties used without your explicitly creating them. But especially for the input properties (e.g. Desired_Density), it's good to create them yourself so you can initialize it to the values you want - otherwise, the simulation automatically creates them with 0 as the default value. Pull up the Simulation Properties editor, using Tools->Simulation Properties and add the following properties:
|
Once you have your properties set, make sure you hit the Save button to save them.
Please note that we capitalized the DESIRED_DENSITY and the PERCENT_BURNT to make it easier for users to tell which simulations properties they need to manipulate or look at for their experimentation.
Updating the world to include Controller and Start_Here agents
Add a controller agent and a Start_Here agent to your world, save your world, and you are ready to start data collection for the Sampling and Bivariate Data Analysis unit.