简介:Inthispaper,weinvestigatetheproblemofasize-constrainedk-coregroupquery(SCCGQ)insocialnetworks,takingbothuserclosenessandnetworktopologyintoconsideration.Morespecifically,SCCGQintendstofindagroupofhusersthathasthehighestsocialclosenesswhilebeingak-core.SCCGQcanbewidelyappliedtoeventplanning,taskassignment,socialanalysis,andmanyotherfields.Incontrasttoexistingworkonthek-coredetectionproblem,whichaimstofindak-coreinasocialnetwork,SCCGQnotonlyfocusesonk-coredetectionbutalsotakessizeconstraintsintoconsideration.Althoughtheconventionalk-coredetectionproblemcanbesolvedinlineartime,SCCGQhasahighercomplexity.TosolvetheproblemofSCCGQ,weproposeaBlastScatter(BS)algorithm,whichappointsthequerynodeasthecentertobeginoutwardexpansionsviabreadthsearch.Ineachoutwardexpansion,BSfindsanewcenterthroughagreedystrategyandthenselectsmultipleneighborsofthecenter.TospeeduptheBSalgorithm,weproposeanadvancedsearchalgorithm,calledBoundedExtension(BE).Specifically,BEcombinesaneffectivesocialdistancepruningstrategyandatightupperboundofsocialclosenesstoprunethesearchspaceconsiderably.Inaddition,weproposeanoffiinesocial-awareindextoacceleratethequeryprocessing.Finally,ourexperimentalresultsdemonstratetheefficiencyandeffectivenessofourproposedalgorithmsonlargereal-worldsocialnetworks.
简介:作为一种简单而有效的新兴计算技术,差分演化算法(DE)已受到学术界和工程界的广泛关注,并且已经在多峰函数优化,数据过滤,多目标优化等十九个大方向上取得了许多成功应用。为此,对围绕差分演化算法的相关背景,原理、特点、改进等方面进行简单介绍.HookeandJeeves方法是一种经典的局部搜索算法,将其与差分演化算法结合来求解多目标优化问题,提高了解的收敛质量,因而从整体上提高了算法的性能,并且测试结果也说明了该算法的可行性。