Routine Duplication of Post-2000 Patented Inventions by Means of Genetic Programming

1. Routine Duplication of Post-2000 Patented Inventions by Means of Genetic Programming Matthew J. Streeter Genetic Programming, Inc. mjs@tmolp.com Martin A. Keane Econometrics, Inc. makeane@ix.netcom.com John R. Koza Stanford University koza@stanford.edu EuroGP 2002, Kinsale, Ireland April 3-5

2. Overview • Circuit Synthesis using Genetic Programming • Previous Results of Circuit Synthesis using Genetic Programming • Four New Techniques • NODE function • Geometric coordinates • Two new component-inserting functions • Five Post-2000 Patented Circuits • Voltage-to-current converter • High-current load circuit • Cubic signal generator • Register-controlled capacitor • Balun circuit • Results • [Five patented circuits] • Patent Office variation on Turing Test

3. Circuit Synthesis using Genetic Programming

4. Embryo & Test Fixture • Initial circuit contains input and output circuitry plus specially designated modifiable wires. • Subcircuit containing modifiable wires is called embryo; remaining circuitry is test fixture. • Minimal (one-wire) embryo used for all work presented here Example embryo & test fixture

5. Developmental Functions • Component-inserting functions insert electrical component (e.g. resistor, capacitor, transistor) into circuit in place of existing modifiable wire • Topology-modifying functions (e.g. series division, parallel division) alter topology & create new modifiable wires • Connection functions connect to predefined component in test fixture (e.g. input voltage source, output probe point, power supply)

6. Simulation • SPICE (Simulation Program with Integrated Circuit Emphasis) industry standard circuit simulator • Modified GP version of SPICE with robust error handling

7. Fitness measure • Curve matching: integrated difference between output curve for evolved circuit and ideal output curve (time domain or frequency domain) • Constraints: number of components, total capacitance, etc. • Additional objectives: reduction of distortion, noise, etc.

8. Previous Results of Circuit Synthesis using Genetic Programming • Rediscovery of Cauer, M-derived half section, and constant K filters • Voltage reference circuit • Electronic thermometer • Computational circuits for squaring, square root, cubing, cube root, logarithm, Gaussian • RC circuit with gain > 2 (Philbrick circuit) • NAND gate • Digital to Analog Converter • Synthesis and layout of lowpass filter & amplifier • For references, see www.genetic-programming.com

9. Four New Techniques

10. NODE function • Purpose is to connect distant parts of circuit • A NODE with no ancestor NODEs is a top-most node • NODE function causes connection to be made to local top-most node • Old approach (VIA1, VIA2, . . . VIA8) used context-dependent information

11. Geometric Coordinates • Coordinates can be assigned to initial modifiable wire(s) and maintained as circuit is developed • Coordinates used to define behavior of certain developmental functions (Q and PARALLEL) • Should be better than component numbers (old approach) because local information is used (more robust to crossover)

12. Two new component-inserting functions • Q([model], [orientation], [permutation], [development subtree], [development subtree], [development subtree]) • TWO-LEAD([component], [development subtree], [development subtree] • More parameterized versions of previously used functions

13. Five Post-2000 Patented Inventions

14. Voltage-to-current Converter • Two input voltages; output is stable current proportional to difference • Four time-domain fitness cases with various input/output voltages Patented Voltage-to-current Converter (Ikeuchi and Tokuda 2000) Mitsumi Electric Company, Ltd.

15. High-Current Load Circuit • A time-varying amount of current is sunk to ground in response to a control signal • Two time-domain fitness cases with different control signals Patented High-current Load Circuit (Daun-Lindberg and Miller 2001)IBM Corporation

16. Cubic Signal Generator • Cubing computational circuit operating at low voltage (2V power supply) • Four time-domain fitness cases with various input signals & time scales, plus penalty for harmonic distortion Patented Cubic Signal Generator (Cipriani and Takeshian 2000)Conexant Systems, Inc.

17. Register-controlled Capacitor • Circuit equivalent to capacitor whose capacitance is set by a digital register • 2 sets of 8 time-domain fitness cases covering all values of 3-bit register Patented Register-controlled Capacitor (Aytur 2000)Lucent Technologies, Inc.

18. Balun circuit • Divides input signal into two half-amplitude signals 180 degrees out of phase; patented circuit is low voltage • Frequency sweep fitness cases for magnitude & phase of both outputs • Fourier analysis for harmonic distortion Patented Balun Circuit (Lee 2001)Information and Communications University, Taejon

19. Results

20. Voltage-to-current Converter • Evolved circuit has 62% of average absolute error of patent circuit on our 4 fitness cases Best-of-run voltage-to-current conversion circuit from generation 109.

21. High-Current Load Circuit • Evolved circuit duplicates parallel FET transistor structure of patented circuit Best-of-run high-current load circuit from generation 114.

22. Cubic Signal Generator • Evolved circuit has 59% of average absolute error of patented circuit on our 4 fitness cases Best-of-run cubic signal generation circuit from generation 182.

23. Register-controlled Capacitor • Evolved circuit error is 100.6% of patent circuit’s error • Exponential weighting of capacitors duplicated Parsimonious register-controlled capacitor circuit from generation 98.

24. Balun circuit • Evolved solution is better in terms of both frequency response and harmonic distortion Best-of-run balun circuit from generation 84.

25. Patent Office Variation on Turing Test • Original Turing Test involved distinction between male and female typists • GP-produced circuits satisfy Patent Office’s criterion for novelty and inventiveness • More than just “chit chat”, analog circuit design is only performed by exceptional and creative humans

26. Patent Office variation on Turing Test.

27. Routine Duplication of Post-2000 Patented Inventions by Means of Genetic Programming Matthew J. Streeter Genetic Programming, Inc. mjs@tmolp.com Martin A. Keane Econometrics, Inc. makeane@ix.netcom.com John R. Koza Stanford University koza@stanford.edu EuroGP 2002, Kinsale, Ireland April 3-5