The V-World Workbook

Donald Nute
Artificial Intelligence Center
The University of Georgia
Athens, GA 30605

Copyright 2005 Donald Nute

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Exercise 2: Watch Bumble Go!

Start V-World, load the test1 world, and load Bumble. This time, instead of playing the game manually we will let Bumble play the game. Click Leap on the menu bar. When Bumble finally dies, note how many moves he made, and his final Strength and Damage. If Bumble should survive for more than 5,000 moves, click Abort to stop him and record the number of moves as 5,000. Reload test1 and Bumble, and run him again. Do it a third time. Record the number of moves and the causes of death (starved or killed) for the three runs.

Run Bumble for three times in each of the worlds test2--test7, recording the number of moves and the cause of death for each run in each world. Prepare your results in a table.

Bumble moves very fast. To better see what he is doing, select Creep from the menu bar. This will cause Bumble to make one move. By doing this repeatedly, you can get a better idea of how Bumble behaves. There are some other tools you can use to test Bumble's behavior. Options/Change Agent Location will allow you to move Bumble to a new location. After selecting this option on the menu bar, click the screen at the location where you want to relocate Bumble. This will allow you to place Bumble next to the tree, the red cross, the hornet, or any where else. Then you can use Creep to see how Bumble behaves in these situations.

2.1 After you have conducted these experiments, and before you look at the code in bumble_1.0.agt, write a description of how Bumble behaves. From this description, you should be able to predict Bumble's behavior reasonably well in different situations.

Now look over the code in bumble_1.0.agt carefully. Notice that Bumble is defined as a function from perceptions to actions.

2.2 Evaluate the description you wrote for question 2.1. How closely does your description match the instructions in bumble_1.0.agt?

2.3 Is Bumble a simple reflex agent? A model-based reflex agent? A goal-based agent? A utility-based agent? A learning agent? Remember that Bumble could belong to more than one of these categories. Justify your answers.

2.4 Is Bumble a rational agent? Justify your answer explaining the criteria you are using to evaluate Bumble's rationality.

Finally, load Bumble into test1 and move him into different situations using Options/Change Agent Location. Look at the code in bumble_1.0.agt and try to predict how Bumble will move before you click Creep. Run Bumble for one step and see how good your prediction is.

Discussion: The worlds test1--test7 contain only walls, trees, fruit, red crosses, hornets, snails, bug spray, keys, doors, and empty space. Bumble does well in test1 because this environment is resource-rich and the threat level is low (lots more trees and red crosses than hornets.) In test2 and test3, it becomes increasingly difficult for Bumble to survive because resources become scarcer compared to threats. The hornets usually do not kill Bumble directly, but they keep him away from the fruit so that he eventually starves. test4--test7 are very dangerous for Bumble because it is difficult for him to find the resources he needs to stay alive. Bumble should do better in test2 and test3 if he were less timid and used the food resources more efficiently.

Last revised 8/17/2005.