- author = "Asbjoern Djupdal",
- title = "Evolving Static Hardware Redundancy for Defect Tolerant {FPGAs}",
- school = "Department of Computer and Information Science, Faculty of Information Technology, Mathematics and Electrical Engineering, Norwegian University of Science and Technology",
- year = "2008",
- address = "Trondheim, Norway",
- month = "24 " # apr,
- isbn13 = "978-82-471-6874-5",
- keywords = "genetic algorithms, genetic programming, cartesian genetic programming, EHW",
-
URL = "
http://www.idi.ntnu.no/research/doctor_theses/djupdal.pdf",
- size = "136 pages",
-
abstract = "Integrated circuits have been in constant progression
since the first prototype in 1958. The semiconductor
industry has maintained a constant rate of
miniaturisation of transistors and wires, resulting in
ever increasing speed, size and complexity of circuits.
One challenge that has always been present is reduced
yield due to production defects. A certain amount of
chips must be scrapped because production defects have
rendered the chips unusable. Recent predictions suggest
that the average number of production defects per chip
will rise drastically in the future as CMOS scaling
approaches the physical limits of what is possible to
manufacture. If these predictions are true, circuits
should exhibit some level of tolerance to defects so to
keep yield at acceptable levels.
The main contribution of the thesis is to the field of defect tolerance, with a focus on FPGAs. Apart from the widespread employment of FPGAs, two technical reasons make the FPGA especially suited for inclusion of defect tolerance techniques. The regular structure of the FPGA can be exploited for efficient redundancy techniques. In addition, the FPGA can be seen as a bridge between production and the application designer. Through defect tolerance techniques incorporated transparently in the FPGA, a fully functioning gate array can be provided to the application designer despite defects from production.
The approach taken in this thesis is to search for new ways of introducing static hardware redundancy in a circuit through the application of artificial evolution. However, the challenge of applying evolutionary techniques provided a secondary contribution. The work provides a contribution to the field of artificial evolution and the subfield evolvable hardware (EHW) by addressing ways in which such techniques may be applied to search for non-specifiable structures. The work is also bridging the fields of EHW and traditional hardware design and reliability metrics have been investigated for the purpose of comparing evolved and traditionally designed circuits.
Redundant structures are first evolved for gate level circuits where both voter based solutions and more intricate non-voter based solutions are achieved. Transistor level redundancy structures are targeted next to approach the main goal of defect tolerance for FPGAs. A defect tolerant inverter is evolved which forms the basis of a general defect tolerance technique, termed the Multiple Short-Open (MSO) technique. The FPGA look-up table (LUT) is one of the essential components of the FPGA and a defect tolerant LUT is, therefore, constructed applying the MSO technique. An evolutionary experiment is also conducted where a defect tolerant 1-input LUT is evolved directly.",
-
notes = "http://www.idi.ntnu.no/news/index.php?news=112
24th of April Asbjoern Djupdal completed his trial lecture and thesis defence, and he will eventually be awarded the PhD degree. The PhD was completed at the Computer Architecture and Design group, with associate professor Pauline Haddow as supervisor.
He defended his PhD thesis: Evolving Static Hardware Redunancy for Defect Tolerant FPGAs",
