EVOLVINGBUILDINGBLOCKSFORDESIGNUSINGGENETIC ENGINEERING A FO(4)

Abstract. This paper presents a formal approach to the evolution of a representation for use in a design process. The approach adopted is based on concepts associated with genetic engineering. An initial set of genes representing elementary building blocks

EvolvingBuildingBlocksforDesignUsingGeneticEngineering

0.8

1-COMPLEXITY2-COMPLEXITY3-COMPLEXITY4-COMPLEXITY5-COMPLEXITY6-COMPLEXITY7-COMPLEXITY8-COMPLEXITY130.7

FRACTION OF COMPLEX GENES 0.60.50.40.30.2

0.1

0020406080100GENERATIONS120140160180

Figure10.Thefractionofcompositebuildingblockswithdifferentcomplexitiesinthetotalpoolofthebuildingblocksusedtoassemblethepopulationvs.generationnumber.This gureshowsthebuildingblocksofdifferentcomplexitieswhicharesummedtoproducethetotalfractionshowninFigure9.

inthetotalfractionofcompositebuildingblocks.Fromgenerations40to70thistotalfractionisstablewithapproximatelyhalfofbuildingblocksof1-complexityandhalfof2,3and4-complexities.Thenthenumberof1-complexityblocksandtotalnumberofcomplexblocksdeclinessharplyandfrom70until110generationatransitionalprocessoccurswithacomplexredistributionofpopulationsbetweenrepresentationswithdifferentcomplexities.Attheendofthisperiodthebuildingblocksof8-complexitysaturatethepopulationwhenthefractionsoftheothercom-plexbuildingblocksareshiftedtowardsanoiselevelonly.OneoftheevolutionpathsinthespaceofcomplexbuildingblocksisshowninFigure11(a).SomeofthedesignsproducedareshowninFigure11(b).Herearrowsshowwhichpre-viouslyevolvedcompositebuildingblocksareusedtoassemblethenewbuildingblock.The0-complexityblockanditscontributionsareomitted.Aswealreadynotedcompositeblocksofthesamecomplexitylevelsometimeshavedifferentnumbersofelementarycomponents.Coincidently,the5-complexityblockisre-producedagainintherepresentationsof6-,7-and8-complexitiesandisoneofthedominantblocksattheendoftheevolutionaryprocess.

Usingtargetedrepresentation.

Thesetoftargetedbuildingblocksevolvedduringthisprocessisthenusedasaninitialsetofbuildingblocksduringthesecondexperimentwhenweproducethedesignswithmaximaltotalareaofholesinsideandmaximalnumberofconnec-tionsbetweentheseholesinsidethestructure.Herethe tnessesareclosetobut

Abstract. This paper presents a formal approach to the evolution of a representation for use in a design process. The approach adopted is based on concepts associated with genetic engineering. An initial set of genes representing elementary building blocks

14JohnS.GeroANDVladimirA.

Kazakov

Figure11.(a)Anexampleoftheevolutionarypathsintheevolutionofacomplexbuildingblock,(b)someofthedesignsproducedusingthesetofevolvedcomplexblocks.

Abstract. This paper presents a formal approach to the evolution of a representation for use in a design process. The approach adopted is based on concepts associated with genetic engineering. An initial set of genes representing elementary building blocks

EvolvingBuildingBlocksforDesignUsingGeneticEngineering

1

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

015TOTAL FRACTION OF COMPLEX GENES020406080100GENERATIONS120140160180

Figure12.Thefractionofcompositebuildingblockinthetotalpoolofbuildingblockusedtoas-semblethepopulationvs.generationnumber.Inthisexperimenttheobjectivefunctionisthenum-berofclosedholesandthenumberofconnectionbetweentheclosedholesinsidethestructure.Theinitialsetofbuildingblocksisinheritedfromthe rstexperimentandisthetargetedrepresentation.notthesameasthoseusedtoevolvethetargetedrepresentation.Thisexperimentisusedtotestwhetherthetargetedrepresentationislikelytobeusedmorethantheoriginal,elementarybuildingblocks.Ifthetargetedrepresentationisusedratherthantheelementarybuildingblocksthenwehaveachievedourgoalofevolvingarepresentationcanbeusedtoproducedesignswhichexhibitdesiredcharacterist-icsmorereadily.TheresultsareshowninFigures12and13.Onecanseethatthefractionofthecompositebuildingblocksusedtoproducethesedesignsreachesthesaturationlevelduringthe rstfewiterations.Thevisibleredistributionsofthepopulationbetweenthecompositebuildingblocksof5,6and7-complexitiesarepurelysuper cial-thisredistributionoccursbetweenthesamecompositebuildingblockswhicharepresentinalltheserepresentations.Evolutionoftherepresenta-tiondoesnotoccurduringthisexperiment-nonewcomplexbuildingblockwereevolved.Thiscanbeinterpretedasanindicationofclosenessofthetargetedrep-resentationsforbothproblems.Soifthetargetedrepresentationisevolvedforonesetofobjectivesthenitcanbeusefullyappliedtoanyoftheobjectivesetswhichareonlyslightlydifferenttoit.

Effectsofincompleteevolution

Inthisexperimentwerepeatthe rstiterationbutstoptheevolutionprematurelyafteronly60generations.Afterthiswerepeattheseconditerationusingtheevolvedincompletesetofcompositebuildingblocks.TheresultsareshowninFigures14

Abstract. This paper presents a formal approach to the evolution of a representation for use in a design process. The approach adopted is based on concepts associated with genetic engineering. An initial set of genes representing elementary building blocks

16

0.9JohnS.GeroANDVladimirA.Kazakov0.8

0.7

FRACTION OF COMPLEX GENES 0.60.51-COMPLEXITY2-COMPLEXITY3-COMPLEXITY4-COMPLEXITY5-COMPLEXITY6-COMPLEXITY7-COMPLEXITY8-COMPLEXITY0.40.3

0.2

0.1

0020406080100GENERATIONS120140160180

Figure13.Thefractionofcompositebuildingblockswithdifferentcomplexitiesinthetotalpoolofthebuildingblockusedtoassemblethepopulationvs.generationnumberintheexperiment.

1

0.9

TOTAL FRACTION OF COMPLEX GENES 0.80.7 0.60.50.40.3

0.2

0.10102030GENERATIONS405060

Figure14.Thefractionofcompositebuildingblockinthetotalpoolofbuildingblockusedtoas-semblethepopulationvs.generationnumber.Inthisexperimenttheobjectivefunctionisthenumberofclosedholesandthenumberofconnectionsbetweentheclosedholesinsidethestructure.Theini-tialsetofbuildingblocksisinheritedfrom r …… 此处隐藏：5904字，全部文档内容请下载后查看。喜欢就下载吧 ……