if object is on the left of the center 01 if object is on the right of the

If object is on the left of the center 01 if object

This preview shows page 494 - 497 out of 630 pages.

if object is on the left of the center (0,1), if object is on the right of the center d 4 = { 1, if system is near to objects 0, other d 5 = { 1, object is large 0, other d 6 = { 1, object is flat and long 0, other 1 1 0 1 1 detector Receptive filed visual vector object motion vector d 1 d 2 d 3 d 4 Fig. 13.5. A simple visual classifier system Consider an irritation-reaction classifier, which has the following rules: IF a prey(small, moving, nonstriped object) is centered and nonadjacent THEN quickly move toward the object (ALIGN),(FAST). In order to realize this rule, detection value is used as condition, which is expressed in the form of #'s. The 2- triple (0 0) denotes the message generated in input interface. According to above definition, the classifier has the following condition: 00########000001 where the leftmost 2 bits are label, # is irrelevent to bits, and the rightmost 6 bits are the values of prescriptive detectors. If the condition is satisfied, the following message is sent out by classifier: 0100000000000000 where the prefix 01 shows that this message does not come from input interface. This message can be used to set the condition of effector of output interface. The whole rule is as follows: 00#########000001 / 0100000000000000 ALIGN FAST. In a warning system, the following rule can be used to determine whether or not the system is in a warning state:
Image of page 494
478 Advanced Artificial Intelligence IF there is a moving object in the visual field, THEN set up warning timer and send out a warning message. IF the warning timer is not zero, THEN send out a warning message. IF there is no a moving object in the visual field and the timer is not zero, THEN cancel the warning timer. There are two effectors used to build a classifier by using the above rules. The effectors include SET ALERT,DECREMENT ALERT as well as a detector: d 9 = other zero not is timer the if , 0 , 1 The classifier can realize the following three kinds of rules, which have the following forms: 00#############1 / 0100000000000011 SET ALERT 00#####1######## / 0100000000000011 00#####1#######0 /DECREMENT ALERT. A classifier system can be expressed as a network. The most direct method is to use each node in network to denote related classification. Fig. 13.6 gives such a network chart. If a moving object appears in the visual field, then ALERT node is labeled. If the nodes ALERT, SMALL and NOT STRIPED are labeled, then TARGET node is labeled. In order to make this network become a classifier, every node is associated with an identification-tag. In Fig 13.6, the five prefix bits are used as tags. d1=1 [MOVING] d5=0 [SMALL] d6=0 [NOT STRIPED ] d10=0 [NEAR] d10=0 [FAR] 01001 [ALERT] 10001 [TARGET] 11001 [PURSUE] 11010 [APPROACH] 11011 [FLEE] 11100 [FREEZE] 10010 [DANGER] Fig. 13.6. A network chart
Image of page 495
Evolutionary Computation 479 From Fig. 13.6, if a MOVING node is labeled by detector d 1 , then the directed arc from MOVING to ALERT can be built by the following classifier: 00#############1 / 01001########### The directed arc from SMALL NOT STRIPED and ALERT to TARGET then can be built by a single classifier: 00########00#### 01001########### / 10001###########.
Image of page 496
Image of page 497

You've reached the end of your free preview.

Want to read all 630 pages?

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

Stuck? We have tutors online 24/7 who can help you get unstuck.
A+ icon
Ask Expert Tutors You can ask You can ask You can ask (will expire )
Answers in as fast as 15 minutes