Bidirectional incremental evolution in extrinsic evolvable hardware

Abstract

Evolvable Hardware (EHW) has been proposed as a new technique to design complex systems. Often, complex systems turn out to be very difficult to evolve. The problem is that a general strategy is too difficult for the evolution process to discover directly. This paper proposes a new approach that performs incremental evolution in two directions: from complex system to subsystems and from subsystems back to complex system. In this approach, incremental evolution gradually decomposes a complex problem into some sub-tasks. In a second step, we gradually make the tasks more challenging and general. Our approach automatically discovers the sub-tasks, their sequence as well as circuit layout dimensions. Our method is tested in a digital circuit domain and compared to direct evolution. We show that our bidirectional incremental approach can handle more complex, harder tasks and evolve them more effectively, then direct evolution.

A Flexible On-Chip Evolution System Implemented on a Xilinx Virtex-II Pro Device

“…for classification applications, where one category to be classified could be the task of one subsystem. However, work has also been undertaken on automatic partitioning [17]. This process consists of breaking down circuits into sub-circuits and combining them again in order to achieve not only evolvable but also compact circuits.…”

Evolving Multiplier Circuits by Training Set and Training Vector Partitioning

“…The goal is to develop a scheme that could evolve systems for complex realworld applications. There has been undertaken work on decomposition of logic functions by using evolution [12]. Results on evolving a 7-input and 10-output logic function show that such an approach is beneficial.…”

Extrinsic Evolution of Finite State Machine

“…Many papers have discussed the use of extrinsic EHW for the implementation of combinational logic circuit, and different approaches have been proposed [6,7]. One of the advantages of EHW is that if hardware errors occur or a new hardware functionality is required, EHW can alter its own hardware structure in order to accommodate such changes.…”