Page 191 - Mechatronics for Safety, Security and Dependability in a New Era

Ch36-I044963.fm Page 175 Tuesday, August 1, 2006 3:10 PM
Page 175
1, 2006
Tuesday, August
3:10 PM
Ch36-I044963.fm
175
175
behavioral patterns based on the acquired behavioral criteria, and then the reproduced behavioral
patterns are shown on a computer screen. In step 3, a designer selects two preferred behavioral
patterns from the computer screen. Finally, in step 4, the system combines behavioral criteria of the
behaviors selected by the designer into a new behavioral criterion, and then creates a new behavioral
pattern based on the newly combined behavioral criterion and shows the behavioral pattern, again.
Design System

©Acquiring Behavioral Criteria

© Reproducing Behaviors
Designer
© Combining Behavioral Criteria

@ Creating new Behaviors

Figure 2: Design system

Individual of'GA

In our study, the behavioral patterns are produced by Genetic Algorithms (GAs). The variation of each
angle is presented as a GA gene, so that a series of variations from the start point to the target point is
replaced by one individual in the GA. The behavioral patterns are evaluated by the behavioral criteria
prepared or combined in the design system.
Behavioral criteria acquisition from new behaviors

In addition to the existing behavioral criteria, we aimed to construct forms of novel behavioral criteria
from behaviors by Genetic Programming (GP). The set of functions appearing at the internal points of
the GP tree includes "+", "-", "*" and "/". The set of terminals appearing at the external points
includes "x t", "y t", "x t+i", "yt+i", "xt+2", and "yt+2"-

EXPERIMENTS
Demonstrating the proposed design system, we invited both design students and engineering students
to use and evaluate it through 2 experiments. 10 students participated in the experiments including 5
design students who are family with art but do not have any programming experience and 5
engineering students who are good in engineering but not good in art. The participants filled in a
questionnaire to evaluate the design system, after they had used the design system.

System interface

Figure 3 shows the windows presented by the implemented system. The number of individual is set to
200 at each generation. 6 individuals of the 200 individuals are shown on these windows. 2 selected
individuals are shown on the top two windows.