EVOLVINGBUILDINGBLOCKSFORDESIGNUSINGGENETIC ENGINEERING A FO

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:AFORMALAPPROACH.

JOHNS.GEROANDVLADIMIRA.KAZAKOV

KeyCentreofDesignComputing,

DepartmentofArchitecturalandDesignScience,

TheUniversityofSydney,NSW2006Australia.

e-mail:john,kaz@arch.su.edu.au

Abstract.Thispaperpresentsaformalapproachtotheevolutionofarepresentationforuseinadesignprocess.Theapproachadoptedisbasedonconceptsassociatedwithgeneticengineering.Aninitialsetofgenesrepresentingelementarybuildingblocksisevolvedintoasetofcomplexgenesrepresentingtargetedbuildingblocks.Thesetargetedbuild-ingblockshavebeenevolvedbecausetheyaremorelikelytoproducedesignswhichex-hibitdesiredcharacteristicsthanthecommencingelementarybuildingblocks.Thetar-getedbuildingblockscanthenbeusedinadesignprocess.Thepaperpresentsaformalevolutionarymodelofdesignrepresentationsbasedongeneticalgorithmsandusespatternrecognitiontechniquestoexecuteaspectsofthegeneticengineering.Thepaperdescribeshowthestatespaceofpossibledesignschangesovertimeandillustratesthemodelwithanexamplefromthedomainoftwo-dimensionallayouts.Itconcludeswithadiscussionofstyleindesign.

1.Introduction

Thereisanincreasingunderstandingoftherolethatadesignlanguageanditsrep-resentationplayintheef ciencyandef cacyofanydesignprocesswhichusesthatlanguage(Coyneetal.,1990;Geroetal.,1994).Arecurringissueiswhatistheappropriategranularityofalanguage.Ifbuildingblockswhichconstitutetheelementsofadesignmapontoadesignlanguagethenthequestionbecomeswhatisanappropriatescaleforthosebuildingblocksintermsofthe naldesign.Atoneextremewehaveparameterisedrepresentationswherethestructureofadesignis xed,allthevariableswhichgotode neadesignareprede nedandwhatisleftistodeterminethevaluesofthosevariables.Thisde nesaverysmalldesignspace,smallintermsofallthepossibledesignswhichmightbeabletobeproducedforthatdesignsituation.Attheotherextremewehaveelementarybuild-ingblockswhichcanbecombinedinaverylargevarietyofwaysandwhich,asa

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

2JohnS.GeroANDVladimirA.

Kazakov

Se

Figure1.

ingblocks,

variables,isthedesignspaceproducedbyallthepossiblecombinationsoftheelementarybuild-isthedesignspaceproducedbyallthecombinationsofthevaluesoftheparameterisedisthedesignspaceofinterestingdesignsforthedesignsituation.

consequencede neaverylargedesignspace,thevastpartofwhichcoversdesignswhicharelikelytobeuninterestingintermsofthecurrentdesignsituation.Thedesignsproducedbytheparameteriseddesignrepresentationsareasubsetofthosecapableofbeingproducedbytheelementarybuildingblockrepresentation,Fig-ure1.Examplesofbuildingblockrepresentationsincludeconstructivesystemssuchasdesigngrammarsasexempli edbyshapegrammars(Stiny,1980b).Ex-amplesofparameterisedvariablerepresentationsincludeawidevarietyofdesignoptimizationformulations(Gero,1985).

Theadvantageoftheuseoftheelementarybuildingblocksrepresentationisthecoverageoftheentiredesignspacetheyprovide,whereastheadvantageoftheparameterisedvariablerepresentationistheef ciencywithwhichasolutioncanbereached.

Wepresenthereaformalapproachwhichgeneratesatargetedrepresentationofadesignproblem.Atargetedrepresentationistheonewhichcloselymapsontotheproblemathand.Asanexampleconsideralayoutplanningprobleminarchi-tecturaldesign.Onerepresentationmaybeatthematerialmolecularlevel,wheremoleculescanbecombinedtomakeavarietyofmaterialsandparticularcombina-tionsinspaceproducephysicalobjects;herethepotentialsolutionspaceincludesdesignswhichbearnorelationstoarchitecture.Atargetedrepresentationsmaybetorepresentroomssuchthatthepotentialsolutionspaceprimarilyincludesdesignswhichareallrecognizablyarchitecturallayouts.

Inordertosimplifyouranalysisweconsiderdesignswhichareassembledfrom

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

3

Figure2.ThesetofbuildingblocksforFroebel’skindergartengifts(Stiny,1980b).

some nitecollectionofspatialelements(wecallthembuildingblocksorcompon-ents)alongwithassemblyrules.Itisassumedthattheassemblyrulesdonotaffectthecomponents-thedesignobjectisaunionofnon-overlappingbuildingblocks.Westartwithsomesetofbuildingblockswhichwecallelementarycomponents.Itisassumedthattheycannotbedecomposedintoanysmallerones.Wecallasetofbuildingcomponentsandassemblyrulesarepresentationofthedesignproblemandthesetofelementarycomponentsandcorrespondingrulesthebasicrepresent-ation.Wecallitarepresentationbecauseitimplicitlyde nesthesetofalldesigns(designstatespace)whichcanbeproducedusingthissetofbuildingblocksandassemblyrules.

ThekindergartengiftsofFroebel(Stiny,1980b)isatypicalexampleofsuchtypesofdesignproblem.Oneofmanypossibleelementaryrepresentationsandas-semblyrulesforitisshowninFigures2and3.Onecaneasilyextenditbyaddingfurtherelementarybuildingblocksand/orfurtherassemblyrules.

Targetedrepresentations

uallythedesignerisinterestedinsomeparticularclassofdesigns.Assumewehavesomeadditionalsetofcompositebuildingblocksandanadditionalsetofassemblyrulestohandlethem.Wecancalculatethenumberofthesecompositebuildingblockswhichcanbefoundinallpossibledesignsinthatparticularclassandthenumberofelementarybuildingblocksusedtobuildtherestofthesedesigns(eachelementarybuildingblockshouldbecountedonlyonceasamemberofcom …… 此处隐藏：6357字，全部文档内容请下载后查看。喜欢就下载吧 ……