Case Study

A few points made in the previous chapters need expanding to more fully explain how they affect the target selection. We'd like to determine what properties of the situation affect the likelihood of damage, and the benefit of particular targets.

First, certain features affect the problem directly. Figure 20.1 shows the four points in space involved in the problem with five key features:

Figure 20.1. Possible scenario with one selected target, close to the predicted position of the enemy.

• The distance from the origin to the target; the closer the target, the higher the probability of hitting it.

• The distance between the enemy's position and the target; the further the enemies, the less likely they are of ending up at the target.

• The distance between the selected target and the estimated enemy position (because this is a relatively accurate prediction).

• The relative angle between the trajectory of the projectile and the velocity of the enemy.

• The relative angle between the velocity of the enemy and the vector from the target to the estimated position.

Second, some properties of the animat may influence the choice of targets:

• The angular divergence from the heading of the animat to the target, as well as the angular velocity; some targets will be easier to aim at.

• Both the speed of travel and the direction of the movement can affect the ability to hit particular targets.

Given these key factors, it may be possible to guess how much damage the projectile will inflict upon the enemy. Because manually designing a system that can predict the damage is complex enough, a perceptron is used to learn this task.