Introduction
In its most fundamental form an evolutionary algorithm manipulates a population of individuals where each individual describes how to construct a candidate circuit. Each circuit is assigned a fitness, which indicates how well a candidate circuit satisfies the design specification. The evolutionary algorithm uses stochastic operators to evolve new circuit configurations from existing ones. Done properly, over time the evolutionary algorithm will evolve a circuit configuration that exhibits desirable behavior.
Each candidate circuit can either be simulated or physically implemented in a reconfigurable device. Typical reconfigurable devices are field-programmable gate arrays (for digital designs) or field-programmable analog arrays (for analog designs). At a lower level of abstraction are the field-programmable transistor arrays that can implement either digital or analog designs.
The concept was pioneered by Adrian Thompson at the University of Sussex, England, who in 1996 evolved a tone discriminator using fewer than 40 programmable logic gates and no clock signal in a FPGA. This is a remarkably small design for such a device and relied on exploiting peculiarities of the hardware that engineers normally avoid. For example, one group of gates has no logical connection to the rest of the circuit, yet is crucial to its function.
Read more about this topic: Evolvable Hardware
Famous quotes containing the word introduction:
“The role of the stepmother is the most difficult of all, because you can’t ever just be. You’re constantly being tested—by the children, the neighbors, your husband, the relatives, old friends who knew the children’s parents in their first marriage, and by yourself.”
—Anonymous Stepparent. Making It as a Stepparent, by Claire Berman, introduction (1980, repr. 1986)
“Such is oftenest the young man’s introduction to the forest, and the most original part of himself. He goes thither at first as a hunter and fisher, until at last, if he has the seeds of a better life in him, he distinguishes his proper objects, as a poet or naturalist it may be, and leaves the gun and fish-pole behind. The mass of men are still and always young in this respect.”
—Henry David Thoreau (1817–1862)
“For better or worse, stepparenting is self-conscious parenting. You’re damned if you do, and damned if you don’t.”
—Anonymous Parent. Making It as a Stepparent, by Claire Berman, introduction (1980, repr. 1986)