are run on actual hardware. In extrinsic evolution, only the final best solution in the final population of the evolutionary algorithm is physically implemented, whereas with intrinsic evolution every individual in every generation of the EA's population is physically realized and tested. Future research directions Evolvable hardware problems fall into two categories: original design and adaptive systems. Original design uses evolutionary algorithms to design a system that meets a predefined specification. Adaptive systems reconfigure an existing design to counteract faults or a changed operational environment. Original design of digital systems is not of much interest because industry already can synthesize enormously complex circuitry. For example, one can buy intellectual property cores to synthesize USB port circuitry, ethernet microcontrollers and even entire RISC processors. Some research into original design still yields useful results, for example genetic algorithms have been used to design logic systems with integrated fault detection that outperform hand designed equivalents. Original design of analog circuitry is still a wide-open research area. Indeed, the analog design industry is nowhere near as mature as is the digital design industry. Adaptive systems has been and remains an area of intense interest. See also Self-management (computer science) Programmable logic device References Further reading External links NASA-DoD-sponsored conference 2004 NASA-DoD-sponsored conference 2005 NASA/ESA Conference on Adaptive Hardware and Systems (AHS-2006) NASA/ESA Conference on Adaptive Hardware and Systems (AHS-2007) NASA used a genetic algorithm to design a novel antenna (see PDF paper for details) Evolutionary Electronics at the University of Sussex Electronic design