11

Evolution Evolution in in materiomaterio

Julian Francis Miller Julian Francis Miller Department of ElectronicsDepartment of ElectronicsThe University of York, UKThe University of York, UK

http://www.elec.york.ac.uk/staff/jfm7.htmlhttp://www.evolutioninmaterio.com

jfm@ohm.york.ac.uk

22

What is Evolution What is Evolution in in materiomaterio??

�� The manipulation of a physical system The manipulation of a physical system by computer controlled evolution (CCE) by computer controlled evolution (CCE) of its physical propertiesof its physical properties

33

Programming with modelProgramming with model--free free mattermatter

�� The dominant view of computation is The dominant view of computation is based on Boolean logic. Yet based on Boolean logic. Yet wewe are not are not based on thatbased on that

�� How can we utilize the magnificent How can we utilize the magnificent potential for computation in the physical potential for computation in the physical world without understanding the rules of world without understanding the rules of the game?the game?

44

Why we should be interested Why we should be interested in evolution in evolution in in materiomaterio??

�� Natural evolution is Natural evolution is par excellencepar excellence an an algorithm that exploits the physical properties algorithm that exploits the physical properties of materialsof materials

�� Artificial Evolution may be more effective Artificial Evolution may be more effective when the configurable medium has a rich and when the configurable medium has a rich and complex physicscomplex physics

�� It holds the promise that we can discover new It holds the promise that we can discover new computational devicescomputational devices

55

From Evolution From Evolution in in simulosimulo to to EvolutionEvolution in in materiomaterio

�� Evolving using simulated physicsEvolving using simulated physics

�� Evolving in simulation and then buildingEvolving in simulation and then building

�� Evolving without simulation (in Evolving without simulation (in materiomaterio))

66

Evolution in Evolution in simulosimulo: a classic: a classic

Karl Sims, 1994

77

From simulation to physical From simulation to physical implementation: static structuresimplementation: static structures

(top) Funes and Pollack, Artificial Life 1998.

(bottom left) Linden and Altshuler, Microwave Journal 1996

(bottom right) Lohn et al. 2004

88

From simulation to physical From simulation to physical implementation: moving structuresimplementation: moving structures

Pollack et al, Artificial Life, 2001

99

Properties required by evolvable Properties required by evolvable physical media?physical media?

�� Their physical properties must be affected Their physical properties must be affected by changes to external controllable by changes to external controllable physical variablesphysical variables

�� To be evolvable the media must beTo be evolvable the media must be�� Strong criterion: must be able to be resetStrong criterion: must be able to be reset

�� Weak criterion: strong genetic inheritance of Weak criterion: strong genetic inheritance of physical characteristicsphysical characteristics

1010

Some dangers of conventional Some dangers of conventional programmingprogramming……

�� ““In conventional design the vast majority of In conventional design the vast majority of interactions that could possibly contribute to the interactions that could possibly contribute to the problem are deliberately excludedproblem are deliberately excluded”” (Michael (Michael Conrad 1988)Conrad 1988)

�� ““Get a computer to do what needs to be done, Get a computer to do what needs to be done, without telling it how to do itwithout telling it how to do it”” (Arthur Samuel (Arthur Samuel 1983)1983)

�� ““Nothing makes sense in computing except in Nothing makes sense in computing except in the light of evolutionthe light of evolution”” ((ToffoliToffoli 2005) 2005)

1111

Making matter computeMaking matter compute

1212

How do you How do you evolveevolve matter to matter to compute? compute?

Configuration dataConfiguration data

Incident signalIncident signal Modified signalModified signal Test for Test for desired desired responseresponse

Configuration population subject to Configuration population subject to artificial evolutionartificial evolution

Fitness Fitness calculationcalculation

1313

Has anybody demonstrated Has anybody demonstrated evolvable physical media?evolvable physical media?

�� Gordon Gordon PaskPask? 1958 ? 1958 -- Ferrous sulphateFerrous sulphate�� Jonathan Mills? 1996 Jonathan Mills? 1996 –– conducting plastic foam conducting plastic foam �� Adrian Thompson, 1996 Adrian Thompson, 1996 -- siliconsilicon�� Adrian Adrian StoicaStoica, Didier Keymeulen, Riccardo , Didier Keymeulen, Riccardo ZebulumZebulum, ,

2000 2000 -- siliconsilicon�� HuelsbergenHuelsbergen, Rietman, , Rietman, SlousSlous, 1998 , 1998 -- siliconsilicon�� Derek Linden, 2001 Derek Linden, 2001 -- reed switch arrayreed switch array�� Jon Bird and Paul Layzell, 2002 Jon Bird and Paul Layzell, 2002 -- siliconsilicon�� Simon Harding and Julian Miller, 2004 Simon Harding and Julian Miller, 2004 -- liquid crystalliquid crystal

1414

Gordon Gordon PaskPask

““Physical analogues to the Physical analogues to the Growth of a ConceptGrowth of a Concept””Mechanization of Thought Mechanization of Thought Processes, Symposium 10, Processes, Symposium 10, National Physical Laboratory, National Physical Laboratory, H.M.S.O (London) pp 765H.M.S.O (London) pp 765--794, 1958.794, 1958.

1515

What What PaskPask was trying to dowas trying to do

�� Build a machine without any explicit definition Build a machine without any explicit definition of its parts (selfof its parts (self--building)building)

�� Able to build its own Able to build its own ““relevance criteriarelevance criteria”” and and find the observables required to solve the find the observables required to solve the tasktask

�� He needed a He needed a ‘‘physically richphysically rich’’ machine which machine which could be adaptively steeredcould be adaptively steered

1616

Schematic of Electrode array Schematic of Electrode array and Ferrous sulphate mediumand Ferrous sulphate medium

1717

What What PaskPask diddid

“…“…the rewarding procedure acts by supplying the rewarding procedure acts by supplying more current for constructing threads whenever more current for constructing threads whenever the mode of problem solution, implied by the the mode of problem solution, implied by the existence of a certain thread structure, satisfies existence of a certain thread structure, satisfies an external criterion, such as maximising the an external criterion, such as maximising the output of the process. In this learning by reward output of the process. In this learning by reward procedure some threads flourish, others will procedure some threads flourish, others will prove abortive. prove abortive. It is a lengthy and inefficient kind It is a lengthy and inefficient kind of learning not unlike natural selectionof learning not unlike natural selection”” -- ((PaskPask1958)1958)

1818

““We have made an earWe have made an ear…”…”

�� ““We have made an ear and a magnetic receptor. We have made an ear and a magnetic receptor. The ear can discriminate two frequencies, one of The ear can discriminate two frequencies, one of the order of fifty cycles per second and the other the order of fifty cycles per second and the other on the order of one hundred cycles per second. on the order of one hundred cycles per second. The The ‘‘training proceduretraining procedure’’ takes approximately half takes approximately half a day and once having got the ability to a day and once having got the ability to recognize sound at all, the ability to recognize recognize sound at all, the ability to recognize and discriminate two sounds comes more and discriminate two sounds comes more rapidlyrapidly…”…” -- (see (see CarianiCariani 1993)1993)

1919

Jon Mill’s Extended Analogue Computer

Computing substrate is conducting packaging foam

Mills 1996

2020

Extended Analogue Computer

INPUT

LLA

LLA LLA

LLA

OUTPUT

CURRENT

SINK/SRC

2121

Quantum Dot ComputationQuantum Dot Computation

�� Dots have two spin statesDots have two spin states�� Array acts as a two Array acts as a two

dimensional cellular dimensional cellular automatonautomaton

�� Magnetic probes set the Magnetic probes set the initial spin states of the dotsinitial spin states of the dots

�� The dots interact and the The dots interact and the states of the output dots are states of the output dots are readread

�� In principle an evolutionary In principle an evolutionary algorithm could decide the algorithm could decide the initial CA configurationinitial CA configuration

For more detail see: Harding, Miller, Rietman Journal of Unconventional Computing, 2008

2222

Generic Generic in in silicosilicoevolvable platform evolvable platform

FPTA Cell

FPGA Cell

2323

Adrian Thompson’s experiment

Thompson 1996

2424

The functional circuit

2525

Thompson and Thompson and LayzellLayzell’’ss ConclusionConclusion

�� Core of timing mechanism is a subtle Core of timing mechanism is a subtle property of the VLSI mediumproperty of the VLSI medium

�� They ruled out:They ruled out:�� glitches, beat frequenciesglitches, beat frequencies

�� metastabilitymetastability

�� thermal timethermal time--constants (selfconstants (self--heating)heating)

�� Evolution has exploited properties of the Evolution has exploited properties of the system that are at present unknownsystem that are at present unknown

2626

Paul Layzell: Evolvable Paul Layzell: Evolvable MotherboardMotherboard

Layzell 1998

2727

An evolved inverter that used An evolved inverter that used the measurement apparatus as the measurement apparatus as

a circuit component!a circuit component!

2828

Evolved oscillator circuit and output Evolved oscillator circuit and output response (Layzell)response (Layzell)

In 20 runs 10 were successful to within 1% with a minimum amplitude of 100mV

2929

Analysis of evolved oscillatorsAnalysis of evolved oscillators�� Difficult to clarify how the circuits workDifficult to clarify how the circuits work

�� If transistors are replaced by nominally identical ones, the If transistors are replaced by nominally identical ones, the output frequency can change by up to 30%output frequency can change by up to 30%

�� Simulation of circuits with parasitic capacitance failed to Simulation of circuits with parasitic capacitance failed to oscillateoscillate

�� Some oscillators only worked while a nearby soldering iron Some oscillators only worked while a nearby soldering iron was switched on!was switched on!

�� Programmable switchesProgrammable switches’’ characteristics are almost characteristics are almost certainly important for circuit operationcertainly important for circuit operation

3030

An evolved radioAn evolved radio

�� Some circuits that achieved high fitness Some circuits that achieved high fitness were found to be amplifying radio signals were found to be amplifying radio signals (generated by nearby PCs) that were (generated by nearby PCs) that were stable enough over the sampling period to stable enough over the sampling period to give good fitness scoresgive good fitness scores

�� The circuit board tracks were being used The circuit board tracks were being used as an aerial!as an aerial!

Bird and Layzell 2002

3131

Evolution of antennasEvolution of antennas

�� Physical evolution of Physical evolution of antennas using reed antennas using reed switchesswitches

Linden 2001

3232

Evolve and test apparatusEvolve and test apparatus

3333

Evolution Evolution in in silicosilico or or in in materiomaterio??

�� Unconstrained evolution in silicon is possibleUnconstrained evolution in silicon is possible

�� Intrinsic evolution often utilizes incidental Intrinsic evolution often utilizes incidental environmental effects to achieve a solutionenvironmental effects to achieve a solution

�� Although these can be a nuisance we should not give Although these can be a nuisance we should not give up. up. It is too early to worry about analysis.It is too early to worry about analysis.

�� Other material systems may have advantages. At the Other material systems may have advantages. At the very least evolution may tell us that computational very least evolution may tell us that computational circuits can be constructed in unusual systems. This circuits can be constructed in unusual systems. This may inspire conventional design in such systems (i.e. may inspire conventional design in such systems (i.e. evolution as a discovery tool)evolution as a discovery tool)

3434

What material systems could we What material systems could we use?use?

�� Liquid crystalLiquid crystal

�� Conducting and Conducting and electroactiveelectroactive polymerspolymers

�� ElectrochromicElectrochromic glassglass

�� Voltage controlled colloidsVoltage controlled colloids

�� Irradiated SiliconIrradiated Silicon

�� LangmuirLangmuir--Blodgett filmsBlodgett films

�� nanoparticlenanoparticle suspensionssuspensions

�� microbial consortiamicrobial consortia

�� Excitable media (reaction diffusion systems)Excitable media (reaction diffusion systems)

�� Biological neuronsBiological neurons

3535

Effects of applied fields on Effects of applied fields on nanoparticlenanoparticle suspensionssuspensions

�� Gold Gold nanoparticlesnanoparticles in water in water form wires and other structures form wires and other structures under the influence of an under the influence of an alternating electric fieldalternating electric field

Source: http://www.physorg.com/news122660454.html

�� Scientists at Rensselaer Scientists at Rensselaer Polytechnic Institute found that Polytechnic Institute found that the contact angle of a droplet the contact angle of a droplet of of nanofluidnanofluid solution changes solution changes when exposed to an electric when exposed to an electric field. February 19, 2008field. February 19, 2008

Hermanson et al., Science, 2001

3636

Computation through reactionComputation through reaction--diffusion processesdiffusion processes

Massively parallel computing deviceMassively parallel computing device��micromicro--volumes of the chemical volumes of the chemical medium act as elementary processors; medium act as elementary processors; data and the results of the computation data and the results of the computation are encoded as concentration profiles are encoded as concentration profiles of the reagents, of the reagents,

��Computation is performed via the Computation is performed via the spreading and interaction of waves caused spreading and interaction of waves caused by the local disturbances.by the local disturbances.��Drawbacks: slow, difficult to control, Drawbacks: slow, difficult to control, uncertain programmabilityuncertain programmability

Adamatzky et al 2005

3737

Liquid crystal programmable Liquid crystal programmable mattermatter?

�� Mesoscopic organisation:Mesoscopic organisation:�� Size between atomic and macroscopic. Such systems Size between atomic and macroscopic. Such systems

exhibit emergent organised behaviourexhibit emergent organised behaviour

smecticsmectic nematicnematic

Organic elongated Organic elongated polar molecules that polar molecules that are affected by electric are affected by electric fieldsfields

Many other types: dyeMany other types: dye--doped, polymer doped, polymer dispersed, conducting, dispersed, conducting, discoticdiscotic

3838

Evolution in Liquid CrystalEvolution in Liquid Crystal

�� It is possible to evolve computational functions It is possible to evolve computational functions in liquid crystal (Harding and Miller 2004 in liquid crystal (Harding and Miller 2004 onwards)onwards)

3939

In In materiomaterio evolution in progressevolution in progress

4040

LC EvolvableLC Evolvable MotherboardMotherboard

GNDGND

INPUT SIGNALINPUT SIGNAL

LC OUTPUTLC OUTPUT

CONFIGURATION CONFIGURATION VOLTAGESVOLTAGES

4141

Genotype representationGenotype representation

0 1 2 6 3 7 2 4 8 3 0 1 7 3 5 1 3 5 …. 0.2 -0.4 1.4 3.4 3.9

Ground (fixed)Ground (fixed)

Input signal Input signal (fixed)(fixed)

Output signal Output signal (fixed)(fixed)

5 input voltages in 5 input voltages in range range --10v to +10v 10v to +10v discretizeddiscretizedin 16bit in 16bit levelslevels

4242

Genetic AlgorithmGenetic Algorithm

�� Population 40Population 40

�� Top 5 genotypes promoted. Population Top 5 genotypes promoted. Population filled with tournament selected (size 5) filled with tournament selected (size 5) others that were mutated (5 mutations others that were mutated (5 mutations each)each)

�� 100 generations.100 generations.

�� It took approximately 1 minute to It took approximately 1 minute to evaluteevaluteeach generationeach generation

4343

Task: Tone discriminatorTask: Tone discriminator�� Evolve a Evolve a ““circuitcircuit”” that can discriminate between that can discriminate between

two possible applied signals: two possible applied signals: �� Signals were square waves, 0Signals were square waves, 0--5V, 100Hz, 5kHz5V, 100Hz, 5kHz

�� Test sequence:Test sequence:�� 250ms 5Khz, 250ms 100Hz, 250ms 5KHz 250ms 5Khz, 250ms 100Hz, 250ms 5KHz �� Reward: count percentage output < 0.1V for 100Hz and Reward: count percentage output < 0.1V for 100Hz and

output >0.1V for 5kHzoutput >0.1V for 5kHz

�� Many pairs of frequencies were tried and Many pairs of frequencies were tried and proved successfulproved successful

4444

Best evolved Best evolved ““circuitcircuit”” responseresponse

4545

2nd Input Frequency

1stIn

put F

requ

ency

100

10

Average Average generations to generations to

find solutionfind solution

Evolved tone discriminators for Evolved tone discriminators for other frequenciesother frequencies

4646

Some Analysis Some Analysis

�� CrosspointCrosspoint switches unlikely to be involved as they are switches unlikely to be involved as they are designed for high frequency audio/video signals.designed for high frequency audio/video signals.�� feedthroughfeedthrough capacitance is 0.2pF and the switch capacitance is capacitance is 0.2pF and the switch capacitance is

20pF.20pF.

�� Is the LCD is acting as a configurable RC network?Is the LCD is acting as a configurable RC network?

�� When an evolved configuration is reloaded it fails to work, When an evolved configuration is reloaded it fails to work, however if a population contains that individual it evolves to however if a population contains that individual it evolves to work in 2work in 2--3 generations3 generations

4747

Robot TaskRobot Task

�� Evolve a liquid crystal display to control a Evolve a liquid crystal display to control a simulated robot simulated robot

�� Robot must explore the environment and avoid Robot must explore the environment and avoid wall collisionwall collision

�� The robot can The robot can ““hearhear”” frequencies in each of two frequencies in each of two ““earsears”” whose pitch is inversely proportional to whose pitch is inversely proportional to the distance of the ear from point of contact with the distance of the ear from point of contact with barrierbarrier

�� Robot has two motorsRobot has two motors

4848

A Robot Controller In LCA Robot Controller In LCSonar 1Sonar 1

Sonar 2Sonar 2Sonar 2

Motor 1Motor 1

Motor 2Motor 2

Liquid CrystalLiquid Crystal

Configuration Configuration voltages, from PCvoltages, from PC

4949

Connections to LC for Robot TaskConnections to LC for Robot Task

GNDGND

INPUT SIGNALSINPUT SIGNALS

MOTOR MOTOR OUTPUTSOUTPUTS

CONFIGURATION CONFIGURATION VOLTAGESVOLTAGES

5050

Near objects

Far objects

�Output from sonar is a square wave whose frequency is inversely proportional to “time of flight”

�Output scales from 1hz to 5kHz

�Distance is sampled every 100ms, and output oscillator frequencies updated. Adds noise and slow response to external change.

““SonarSonar”” technical stufftechnical stuff

5151

Evolved SolutionsEvolved Solutions

1 2

3 4

5252

The future: An evolvable The future: An evolvable microelectrode array microelectrode array

device?device?

http://www.multichannelsystems.com/

5353

Further workFurther work�� Build a evolvable microelectrode array Build a evolvable microelectrode array

devicedevice�� Use different types of LC, Use different types of LC, nanoparticlenanoparticle

suspensionssuspensions�� Attempt to evolve solutions to much Attempt to evolve solutions to much

harder problemsharder problems�� Understand how the devices workUnderstand how the devices work�� Examine potential of other physical Examine potential of other physical

systemssystems

5454

ThoughtsThoughts

�� Evolution in Evolution in materiomaterio is an automated is an automated discoverydiscovery process. It can help us find process. It can help us find material substrates that can be utilized for material substrates that can be utilized for computationcomputation

�� It potentially can allow It potentially can allow ““programmingprogramming”” at a at a molecular level (massively parallel)molecular level (massively parallel)

�� It is probably most useful for tasks where it It is probably most useful for tasks where it is difficult to construct efficient is difficult to construct efficient conventional solutions (i.e. AI problems)conventional solutions (i.e. AI problems)

5555

ConclusionsConclusions

�� To be able to evolve things you need To be able to evolve things you need phenotypic richnessphenotypic richness

�� It is feasible for us to get computer controlled It is feasible for us to get computer controlled evolution to create technology for us. Not tell evolution to create technology for us. Not tell it what technology it must use. it what technology it must use.

�� We know it has already created the We know it has already created the technology of living things.technology of living things.

�� We need more people to try We need more people to try ““evolution in evolution in materiomaterio””

5656

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