简介:Stationkeepingmode(SKM)forAttitudeOrbitControlSubsystem(AOCS);itisanoperationalapproachregardingtheattitudedynamicscontrol.Theessentialfeaturesofthedesignmethodologyisresearchingthebasictheoryandthenafterwards,makeaniterativedesignapproachusingsomepremise/assumptions,implementingthesystemsimulationthroughtheSimulinkMatlabsoftwarepackage,designingtherequiredcontrollers,monitorandanalyzingtheresponsesuntilthedesigngivethebestresultswithintherangerequired.Firstlythethrusterconfigurationisdesignedtoacquiretheparametersofthetorqueonthesatellite.Next,thecontrollersarebasedonthewellknownPIDcontrollaw.ControllersoptimizetheattitudeandareusedduringthemaneuversforSKM.Afterwardsthesimulationresultsaregiven,andpresentedtodemonstratetheperformanceandvalidityoftheAOCSdesignapproach.FinallythesimulationresultsdemonstratethatalltherequirementswereaccomplishedandtheStationKeepingModewassuccessfullydesigned.
简介:Althoughk-anonymityisagoodwayofpublishingmicrodataforresearchpurposes,itcannotresistseveralcommonattacks,suchasattributedisclosureandthesimilarityattack.Toresisttheseattacks,manyrefinementsofk-anonymityhavebeenproposedwitht-closenessbeingoneofthestrictestprivacymodels.Whilemostexistingt-closenessmodelsaddressthecaseinwhichtheoriginaldatahaveonlyonesinglesensitiveattribute,datawithmultiplesensitiveattributesaremorecommoninpractice.Inthispaper,wecoverthisgapwithtwoproposedalgorithmsformultiplesensitiveattributesandmakethepublisheddatasatisfyt-closeness.Basedontheobservationthatthevaluesofthesensitiveattributesinanyequivalenceclassmustbeasspreadaspossibleovertheentiredatatomakethepublisheddatasatisfyt-closeness,bothofthealgorithmsusedifferentmethodstopartitionrecordsintogroupsintermsofsensitiveattributes.Oneusesaclusteringmethod,whiletheotherleveragestheprincipalcomponentanalysis.Then,accordingtothesimilarityofquasi-identifierattributes,recordsareselectedfromdifferentgroupstoconstructanequivalenceclass,whichwillreducethelossofinformationasmuchaspossibleduringanonymization.Ourproposedalgorithmsareevaluatedusingarealdataset.Theresultsshowthattheaveragespeedofthefirstproposedalgorithmisslowerthanthatofthesecondproposedalgorithmbuttheformercanpreservemoreoriginalinformation.Inaddition,comparedwithrelatedapproaches,bothproposedalgorithmscanachievestrongerprotectionofprivacyandreduceless.
简介:根据古典阴阳互补和现代对偶互补的基本思想,通过罗恩提出的一条简单而统一的新途径,系统地建立了平面框架结构折线型弹塑性动力学的各类非传统Hamilton型变分原理.文中首先给出平面框架结构折线型弹塑性动力学的广义虚功原理的表式,然后从该式出发,不仅能得到平面框架结构折线型弹塑性动力学的虚功原理,而且通过所给出的广义Legendre变换,还能系统地成对导出平面框架结构折线型弹塑性动力学的5类变量分原理的互补泛函,以及1类变量和相空间非传统Hamilton型变分原理的泛函.同时,通过这条新途径还能清楚地阐明这些原理的内在联系.
简介:Thispaperdealswiththeproblemofguaranteedcostcontrolfornonlinearsystemswithtime-varyingdelayswhichisrepresentedbyTakagi-Sugeno(T-S)fuzzymodelswithtime-varyingdelays.Thederivativesoftime-varyingdelayarenotnecessarytobebounded.Basedonthefreeweightingmatrixmethod,sufficientconditionsfortheexistenceoffuzzyguaranteedcostcontrollerviastatefeedbackaregivenintermsoflinearmatrixinequalities(LMIs).Aminimizingmethodisalsoproposedtosearchthesuboptimalupperboundoftheguaranteedcostfunction.Theresultsaredelay-dependentbutcontaindelay-independentcriteriaasaspecialcase.Anumericalexampleispresentedtodemonstratetheeffectivenessandlessconservativenessofourwork.