简介:1.IntroductionInthispaperweconsiderCauchyproblemforaclassofnonhomogeneousNavier-Stokesequationsintheinfinitecylinderwith.Givensatisfyinginthedistributionsensediv,weseekasolutionvectorandapressurefunctionP(t,x)suchthatwhereisanonlinearvector-valuedfun...
简介:Inthispaperwewillshowthatifanapproximationprocess{Ln}n∈Nisshapepreservingrelativetotheconeofallk-timesdifferentiablefunctionswithnon-negativek-thderivativeon[0,1],andtheoperatorsLnareassumedtobeoffiniterankn,thentheorderofconvergenceofDkLnftoDkfcannotbebetterthann2evenforthefunctionsxk,xk+1,xk+2onanysubsetof[0,1]withpositivemeasure.Takingintoaccountthisfact,wewillbeabletofindsomeasymptoticestimatesoflinearrelativen-widthofsetsofdifferentiablefunctionsinthespaceLp[0,1],p∈N.
简介:Motiondeblurringisabasicprobleminthefieldofimageprocessingandanalysis.Thispaperproposesanewmethodofsingleimageblinddeblurringwhichcanbesignificanttokernelestimationandnon-blinddeconvolution.Experimentsshowthatthedetailsoftheimagedestroythestructureofthekernel,especiallywhentheblurkernelislarge.SoweextracttheimagestructurewithsalientedgesbythemethodbasedonRTV.Inaddition,thetraditionalmethodformotionblurkernelestimationbasedonsparsepriorsisconducivetogainasparseblurkernel.Butthesepriorsdonotensurethecontinuityofblurkernelandsometimesinducenoisyestimatedresults.ThereforeweproposethekernelrefinementmethodbasedonL0toovercometheaboveshortcomings.Intermsofnon-blinddeconvolutionweadopttheL1/L2regularizationterm.Comparedwiththetraditionalmethod,themethodbasedonL1/L2normhasbetteradaptabilitytoimagestructure,andtheconstructedenergyfunctionalcanbetterdescribethesharpimage.Forthismodel,aneffectivealgorithmispresentedbasedonalternatingminimizationalgorithm.
简介:LetL~2([0,1],x)bethespaceoftherealvalued,measurable,squaresummablefunctionson[0,1]withweightx,andlet■_nbethesubspaceofL~2([0,1],x)definedbyalinearcombinationofJ_0(μ_kx),whereJ_0istheBesselfunctionoforder0and{μ_k}isthestrictlyincreasingsequenceofallpositivezerosofJ_0.Forf∈L~2([0,1],x),letE(f,■_n)betheerrorofthebestL~2([0,1],x),i.e.,approximationoffbyelementsof■_n.Theshiftoperatoroffatpointx∈[0,1]withstept∈[0,1]isdefinedbyT(t)f(x)=(1/π)∫_0~πf((x~2+t~2-2xtcosθ)~(1/2))dθ.Thedifferences(1-T(t))~(r/2)f=∑_(j=0)~∞(-1)~j(_j~(r/2))T~j(t)foforderr∈(0,∞)andtheL~2([0,1],x)-modulusofcontinuityω_r(f,τ)=sup{||(I-T(t))~(r/2)f||:0≤t≤τ}oforderraredefinedinthestandardway,whereT~0(t)=Iistheidentityoperator.Inthispaper,weestablishthesharpJacksoninequalitybetweenE(f,■_n)andω_r(f,τ)forsomecasesofrandτ.Moreprecisely,wewillfindthesmallestconstant■_n(τ,r)whichdependsonlyonn,r,andτ,suchthattheinequalityE(f,■_n)≤■_n(τ,r)ω_r(f,τ)isvalid.
简介:Thepurposeofthepresentpaperistoevaluatetheerroroftheapproximationofthefunc-tionfL1[0,1]byKantorovich-BernsteinpolynomialsinLp-metric(0
简介:Inthispaper,simultaneousuniformapproximationandmeanconvergenceofquasi-HermiteinterpolationanditsderivativebasedonthezerosofJacobipolynomialsareconsideredseparately.Thedegreesofthecorrespondingapproximationsarerespectivelygivenalso.Someknownresultsareimprovedaudextended.
简介:对[0,1]上的L—可积函数ф及α>0定义下列B—D—B算子;本文研究了Mna(ф,x)当α>0时,在LP(0,1](1≤p<+∞)的一致逼近;当α≥1时在LP[O,1]及L1P[0,1]逼近度的量化估计。作者在文[4]中定义了B—D—B算子:其中fnk(X)称为Bézeief基函数文[4]研究的是B—D—B称子在C[0,1]空间中的逼近性质,本文继续[4]的工作,专研究这个算子在LP[0,1](1≤P<+∞)的逼近性质,证明了Mna(фX)当α>0时在LP[0,1]中为一致逼近,并得到了当α≥1时在LP[0,1]及L1P[0,1]中逼近度的量化估计。