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:Thispaperdealswiththeproblemofguaranteedcostcontrolfornonlinearsystemswithtime-varyingdelayswhichisrepresentedbyTakagi-Sugeno(T-S)fuzzymodelswithtime-varyingdelays.Thederivativesoftime-varyingdelayarenotnecessarytobebounded.Basedonthefreeweightingmatrixmethod,sufficientconditionsfortheexistenceoffuzzyguaranteedcostcontrollerviastatefeedbackaregivenintermsoflinearmatrixinequalities(LMIs).Aminimizingmethodisalsoproposedtosearchthesuboptimalupperboundoftheguaranteedcostfunction.Theresultsaredelay-dependentbutcontaindelay-independentcriteriaasaspecialcase.Anumericalexampleispresentedtodemonstratetheeffectivenessandlessconservativenessofourwork.
简介:在Intel平台中,我们也许已经习惯了Intel的垄断——从845到875,似乎P4和赛扬的绝配已非Intel自家产品莫属,类似当年VIA694X在规格上大幅领先440BX,且在价格上战友尽优势的情况目前很难出现。不过,VIA同Intel的和解又让人们看到了更多的选择,PT800就是这一“世纪和解”后的产物,凭借和VIA良好的合作关系,大众第一时间出了基于PT800芯片组的P4M-800T-L主板。