简介:Thepaperproposesreactiongraphsasgraphicalrepresentationsofcomputationalobjects.Areactiongraphisadirectedgraphwithallitsarrowsandsomeofitsnodeslabeled.Computationsaremodledbygraphrewritingofasimplenature.Thebasicrewritingrulesembodytheessenceofboththecommunicationsamongprocessesandcut-eliminationsinproofs.Calculiofgraphsareideentifiedtogiveaformalandalgebraicaccountofreactiongraphsinthespiritofprocessalgebra.Withthehelpofthecalculi,itisdemonstratedthatreactiongraphscapturemanyinterestingaspectsofcomputations.
简介:AnapproximationalgorithmispresentedforaugmentinganundirectedweightedgraphtoaK-edge-connectedgraph.Thealgorithmisusefulfordesigningareliablenetwork.
简介:LetGbeasimplegraphwithnverticesandλn(G)betheleasteigenvalueofG.Inthispaper,weshowthat,ifGisconnectedbutnotcomplete,thenλn(G)≤λn(Kn-11)andtheequalityholdsifandonlyifGKn-11,whereKn-11,isthegraphobtainedbythecoalescenceofacompletegraphKn-1ofn-1verticeswithapathP2oflengthoneofitsvertices.
简介:Parallelgraphreductionisapromisingmodelfornewgenerationcomputerbecauseofitsamenabilitytobothprogrammingandparallelcomputing.Inthispaper,aninitialdesignforaparallelgraphreductionmodel,PGRmodel,ispresented,whichemployseagerevaluationstrategytoexploitconservativeparallelismandprovideswithprimitivesandassociatedtageofnodestosynchronizeconcurrenttasks.Moreover,adirectoperationaldescriptionofgraphreductionintermsofhighlevelinstructions(primitives)isgiventoobtainavirtualmachine,calledPGRVM.
简介:Bargraphsareconvenientforshowingcomparisonsamongitems.Thebarsmaybeeitherhorizontalorvertical,andtheyareusedtoshowtheamountsofdifferentitems.Figure1isanexampleofatypicalbargraph.ThegraphshowstheaveragesalespriceofexistinghomesintheNortheastUnitedStatesforthreeyears——1970,1980,and1997.
简介:ThestarchromaticnumberofagraphwasintroducedbyA.Vince,whichisanaturalgeneralizationofthechromaticnumberofagraph.Inthispaper,thestarchromaticnumbersofgraphproductsG(×)Harediscussedinsomespecialcases.
简介:GivenacompletegraphwithvertexsetXandsubsetsX1,X2,...,Xn,theproblemoffindingasubgraphGwithminimumnumberofedgessuchthatforeveryi=1,2,...,n,GcontainsaspanningtreeonXi,arisesinthedesignofvaccumsystems.Ingeneral,thisproblemisNP-completeanditisprovedthatforn=2and3thisproblemispolynomial-timesolvable.Inthispaper,weprovethatforn=4,theproblemisalsopolynomial-tlmesolvableandgiveamethodtoconstructthecorrespondinggraph.
简介:Wefirstapplynon-negativematrixtheorytothematrixK=D+A,whereDandAarethedegree-diagonalandadjacencymatricesofagraphG,respectively,toestablisharelationonthelargestLaplacianeigenvalueλ1(G)ofGandthespectralradiusp(K)ofK.Andthenbyusingthisrelationwepresenttwoupperboundsforλ1(G)anddeterminetheextremalgraphswhichachievetheupperbounds.
简介:ThetransmissioncapacityofMobileAdHocNetworking(MANET)isconstrainedbythemutualinterferenceofconcurrenttransmissionsbetweennodes.First,thetransmissioncapacityofMANETisstudiedbytheviewofinformationflowbetweennodes.Atthesametime,theproblemthattheinterferencebetweennodesaffectsthetransmissioncapacityofMANETisalsostudiedbythetooloftheeventconflictgraph.Secondly,thepaperpresentsthemethodtocomputethemaximumex-pectantachievablecapacityforthegivenconflictgraph,andconcludesandprovesansufficientcon-ditionthattheinformationflowtransmitsuccessfullybetweennodes.Atlast,theresultsaresimulatedandafittingequationoftransmissioncapacitybetweennodesisgiven.
简介:Graphsarewidelyusedformodelingcomplicateddatasuchassocialnetworks,chemicalcompounds,proteininteractionsandsemanticweb.Toeffiectivelyunderstandandutilizeanycollectionofgraphs,agraphdatabasethatefficientlysupportselementaryqueryingmechanismsiscruciallyrequired.Forexample,SubgraphandSupergraphqueriesareimportanttypesofgraphquerieswhichhavemanyapplicationsinpractice.Aprimarychallengeincomputingtheanswersofgraphqueriesisthatpair-wisecomparisonsofgraphsareusuallyhardproblems.Relationaldatabasemanagementsystems(RDBMSs)haverepeatedlybeenshowntobeabletoefficientlyhostdifferenttypesofdatasuchascomplexobjectsandXMLdata.RDBMSsderivemuchoftheirperformancefromsophisticatedoptimizercomponentswhichmakeuseofphysicalpropertiesthatarespecifictotherelationalmodelsuchassortedness,properjoinorderingandpowerfulindexingmechanisms.Inthisarticle,westudytheproblemofindexingandqueryinggraphdatabasesusingtherelationalinfrastructure.Wepresentapurelyrelationalframeworkforprocessinggraphqueries.Thisframeworkreliesonbuildingalayerofgraphfeaturesknowledgewhichcapturemetadataandsummaryfeaturesoftheunderlyinggraphdatabase.Wedescribedifferentqueryingmechanismswhichmakeuseofthelayerofgraphfeaturesknowledgetoachievescalableperformanceforprocessinggraphqueries.Finally,weconductanextensivesetofexperimentsonrealandsyntheticdatasetstodemonstratetheefficiencyandthescalabilityofourtechniques.
简介:一张签署的图是一张图,一个符号属于每个边。这篇论文从图扩大拉普拉斯算符矩阵的一些基本概念到签署的图。Inparticular,在最少的拉普拉斯算符特征值之间的关系和一张签署的图的失衡的海角被调查。
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简介:Evolutionarycomputationtechniqueshavemostlybeenusedtosolvevariousoptimizationproblems,anditiswellknownthatgraphisomorphismproblem(GIP)isanondeterministicpolynomialproblem.Asimulatedannealing(SA)algorithmfordetectinggraphisomorphismisproposed,andtheproposedSAalgorithmiswellsuitedtodealwithrandomgraphswithlargesize.ToverifythevalidityoftheproposedSAalgorithm,simulationsareperformedonthreepairsofsmallgraphsandfourpairsoflargerandomgraphswithedgedensities0.5,0.1,and0.01,respectively.ThesimulationresultsshowthattheproposedSAalgorithmcandetectgraphisomorphismwithahighprobability.