简介:UnderType-IIprogressivelyhybridcensoring,thispaperdiscussesstatisticalinferenceandoptimaldesignonstepstresspartiallyacceleratedlifetestforhybridsysteminpresenceofmaskeddata.ItisassumedthatthelifetimeofthecomponentinhybridsystemsfollowsindependentandidenticalmodifiedWeibulldistributions.Themaximumlikelihoodestimations(MLEs)oftheunknownparameters,accelerationfactorandreliabilityindexesarederivedbyusingtheNewton-Raphsonalgorithm.Theasymptoticvariance-covariancematrixandtheapproximateconfidenceintervalsareobtainedbasedonnormalapproximationtotheasymptoticdistributionofMLEsofmodelparameters.Moreover,twobootstrapconfidenceintervalsareconstructedbyusingtheparametricbootstrapmethod.TheoptimaltimeofchangingstresslevelsisdeterminedunderD-optimalityandA-optimalitycriteria.Finally,theMonteCarlosimulationstudyiscarriedouttoillustratetheproposedprocedures.
简介:Aco-designschemeofevent-triggeredsamplingmechanismandactivefaulttolerantcontrol(FTC)isdeveloped.Firstly,afaultdiagnosisobserverisdesignedtoestimateboththefaultandthestatesimultaneouslybyusingtheevent-triggeredsampledoutput.SomeH∞constraintsbetweentheestimationerrorsandtheevent-triggeredsamplingmechanismareestablishedtoensuretheestimationaccuracy.Then,basedontheconstraintsandtheobtainedfaultinformation,anevent-triggereddetectorandastaticfaulttolerantcontrollerareco-designedtoguaranteethestabilityofthefaultysystemandtoreducethesensorcommunicationcost.Furthermore,theproblemoftheeventdetectoranddynamicFTCco-designisalsoinvestigated.Simulationresultsofanunstablebatchreactorarefinallyprovidedtoillustratetheeffectivenessoftheproposedmethod.
简介:Fluorescentproteins(FPs)withemissionwavelengthsinthefar-redandinfraredregionsofthespectrumprovidepowerfultoolsfordeep-tissueandsuper-resolutionimaging.Thedevelopmentofred-shiftedFPshasevokedwidespreadinterestandcontinuousengineeringefforts.Inthisarticle,basedonacomputationaldesignandgeneticcodeexpansion,wereportarationalapproachtosignificantlyexpandandred-shiftthechromophoreofgreenfluorescentprotein(GFP).WeappliedcomputationalcalculationstopredicttheexcitationandemissionwavelengthsofaFPchromophoreharboringunnaturalaminoacids(UAA)andidentifyinsilicoanappropriateUAA,2-amino-3-(6-hydroxynaphthalen-2-yl)propanoicacid(naphthol-Ala).OurmethodologyallowedustoformulateaGFPvariant(cpsfGFP-66-Naphthol-Ala)withred-shiftedabsorbanceandemissionspectralmaximaexceeding60and130nm,respectively,comparedtothoseofGFP.TheGFPchromophoreisformedthroughautocatalyticpost-translationalmodificationtogenerateaplanar4-(p-hydroxybenzylidene)-5-imidazolinonechromophore.WesolvedthecrystalstructureofcpsfGFP-66-naphthol-Alaat1.3■resolutionanddemonstratedtheformationofamuchlargerconjugatedn-systemwhenthephenolgroupisreplacedbynaphthol.Theseresultsexplainthesignificantred-shiftingoftheexcitationandemissionspectraofcpsfGFP-66-naphthol-Ala.