1. Self-replication of complex machines

2. Cellular Self-Replication The molecular FPGA is used to CREATE the array of cells in the first place, before differentiation can take place (self-replication)

3. Self-organization So we can make cells appear and disappear at will in a surface of silicon.

4. Self-organization We can then apply all sorts of nice algorithms: Coordinates 1,1 1,2 2,1 1,3 2,2 3,1 1,4 2,3 3,2 4,1 1,5 2,4 3,3 4,2 2,5 3,4 4,3 3,5 4,4 4,5

5. Self-organization We can then apply all sorts of nice algorithms: Coordinates Gradients 1,11,2 2,1 1,3 2,2 3,1 1,4 2,3 3,2 4,1 1,5 2,4 3,3 4,2 2,5 3,4 4,3 3,5 4,44,5

6. Self-organization We can then apply all sorts of nice algorithms: Coordinates Gradients L-Systems 1,11,2 2,1 1,3 2,2 3,1 1,4 2,3 3,2 4,1 1,5 2,4 3,3 4,2 2,5 3,4 4,3 3,5 4,44,5

7. 1,11,2 2,1 1,3 2,2 3,1 1,4 2,3 3,2 4,1 1,5 2,4 3,3 4,2 2,5 3,4 4,3 3,5 4,44,5 Self-organization But all this is (relatively) useless… ABCDE FGHIJ KLMNO PQRST … unless the system can use the algorithms

8. X X Engineering challenges Connectivity – cellular division AB EF C I D G J M X H K N L OPX F FF

9. X X Engineering challenges Connectivity – cellular division AB EF C I D G J M X H K N L OPX F FF

10. X X Engineering challenges Connectivity – cellular division and fault tolerance AB EF C I D G J M X H K N L OPX F FF LX L

11. X X Engineering challenges Connectivity – cellular division and fault tolerance AB EF C I D G J M X H K N L OPX F FF X L

12. Embryonics – The BioWatch

13. MUXTREE Molecule The “molecular” layer of Embryonics is an FPGA

14. Kill a Molecule

15. MUXTREE Molecule The molecules are configured and interconnected to realize a cell

16. MUXTREE Molecule All connections must be re-routed Hardware re-routing is a good option because: The connections are few They rely on fixed, configuration-independent resources (metal lines)

17. Kill Again (Kill a Cell)

18. All connections must be re-routed (including those used to compute the coordinates) In reality, we “cheated”, since we assumed that: The organism is one-dimensional It’s possible to route lines through a faulty cell Self-Repair

19. The mechanism can be extended to two dimensions, by “sacrificing” an entire column whenever a cell dies But it represents a major loss of efficiency Hardware re-routing like in the molecules is not an option, because these connections depend on the configuration and change from one application to the next (different cell sizes, communication patterns, etc.)

20. S T T ?

21. The problem of connectivity Connectivity is a major issue, for self-repair but also in general for developmental systems Solutions for specific cases (e.g., RAM) are common, but general ones are very rare (at logic level, i.e., FPGAs) The problem is that, in conventional FPGAs, all the communication paths are part of the configuration of each individual element One solution was proposed in the POEtic project, a EU project that ran from 2001 to 2004. It involves the development of a novel FPGA circuit for bio-inspired circuits that exploits a dynamic connection network

22. The POEtic molecule An industry-level programmable logic element

23. The POEtic molecule Molecules, through their configuration, can alter their functional structure

24. Connectivity – The POEtic approach The problem is that, in conventional FPGAs, all the communication paths are part of the configuration of each individual element The POEtic solution = dynamically set-up the communication paths at runtime, using a dedicated, configuration-free routing layer

25. Connectivity – The POEtic approach In POEtic, molecular connections (gate-to-gate) are realized conventionally and repair can use hardware re- routing. Cellular connections (processor-to-processor) are realized dynamically in the configuration-free routing layer

26. S T T

28. Next week We can design complex digital circuits that self- replicate These circuits can self-repair And they can re-route their connection network dynamically when needed But what ARE these circuits? In the BioWatch, they were hand-designed processors. Do we need to hand-design every single circuit, or can we find a processor architecture ideally suited to this kind of non-conventional systems?