简介:Thispaperpresentanimprovedpreciseintegrationalgorithmfortransientanalysisofheattransferandsomeotherproblems.Theoriginalpreciseintegrationmethodisimprovedbymeanoftheinve-rseaccuracyanalysissothattheparameterN,whichhasbeentakenasaconstantandanindependentpa-rameterwithoutconsiderationoftheproblemsintheoriginalmethod,canbegeneratedautomaticallybythealgorithmitself.Thus,theimprovdealgorithmisadaptiveandtheaccucacyofthealgorithmisnotdependentonthelengthofthetimestepintheintegrationprocess.Itisshownthatthenumericalresultsobtainedbythemethodproposedaremoreaccuratethanthoseobtainedbytheconventionaltimeintegrationmethodssuchasthedifferencemethodandothers.Fourexamplesaregiventodemonstratethevalidity,accuracyandeffi-ciencyofthenewmethod.
简介:3-Dseismicmodelingcanbeusedtostudythepropagationofseismicwaveexactlyanditisalsoatoolof3-Dseismicdataprocessingandinterpretation.Inthispaperthearbitrarydifferenceandpreciseintegrationareusedtosolveseismicwaveequation,whichmeansdifferenceschemeforspacedomainandanalyticintegrationfortimedomain.Boththeprincipleandalgorithmofthismethodareintroducedinthepaper.Basedonthetheory,thenumericalexamplesprovethatthishybridmethodcanleadtohigheraccuracythanthetraditionalfinitedifferencemethodandthesolutionisveryclosetotheexactone.Alsotheseismicmodelingexamplesshowthegoodperformanceofthismethodeveninthecaseofcomplexsurfaceconditionsandcomplicatedstructures.
简介:Thesoundraytracingmethodcanachievehigheraccuracyindeterminingdepthsandplanpositionswithmultibeamechosoundingsystem.Indataprocessing,actualsoundspeedprofilemustbeusedinthemethod.However,themethodistoocomplicated.Inordertoovercometheshortcoming,thispaperpresentsanewmethod,thepositioncorrectionmethod.Twosituationsareconsideredinthenewmethod,namely,changeofsoundvelocitykeepsconstantgradientinwholewatercolumn(includingNlayers)orindifferentwaterlayer.
简介:有一些18的Qinling隧道。488km在Qinling山的中间从Xi鈥檃n(山西省)位于铁路线到Ankan(四川省)。它是在中国的最长双的轨道铁路隧道并且在世界上占据第三个位置。根据设计,在调查的altimetric控制引起的垂直方向的突破错误为穿透脸的盒子被限制到18mm。因为铺平的线路在长度在120km上到达并且必须在2800m高度温习二座山,一阶的精确铺平和精确严肃测量应该在构造阶段被执行。在这份报纸,与最后的结果分析铺平途径,新技术的申请,一些经验以及办公室计算的地被介绍。由过细的计划,组织和观察,二个隧道结束点之间的垂直差别的最后的精确性仅仅是8mm,并且它提供可靠调查为这个大隧道工程的保证。最后,这垂直差别象114mm一样高与主要测量结果显然区分开来,这被指出。它意味着主要结果不是足够精确的。
简介:Thetransformationmethodtocontrolwaveshasreceivedwidespreadattentioninelectromagnetismandacoustics.However,thismachineryisnotdirectlyapplicabletothecontrolofelasticwaves,becauseithasbeenshownthattheNavier’sequationdoesnotusuallyretainitsformundercoordinatetransformation.Inthisletter,weprovetheforminvarianceoftheNavier’sequationundertheconformalmappingbasedontheHelmholtzdecompositionmethod.Theneededmaterialparametersareprovidedtomanipulateelasticwaves.Thevalidityofthisapproachisconfirmedbyanactivestealthdevicewhichcandisguisethesignalsourcebychangingitsposition.Experimentalverificationsandpotentialapplicationsmaybeexpectedinnondestructivetesting,structuralseismicdesignandotherfields.
简介:Animprovedpreciseintegrationmethod(IPIM)forsolvingthedifferentialRiccatiequation(DRE)ispresented.ThesolutiontotheDREisconnectedwiththeexponentialofaHamiltonianmatrix,andthepreciseintegrationmethod(PIM)forsolvingtheDREisconnectedwiththescalingandsquaringmethodforcomputingtheexponentialofamatrix.TheerroranalysisofthescalingandsquaringmethodfortheexponentialofamatrixisappliedtothePIMoftheDRE.Basedontheerroranalysis,thecriterionforchoosingtwoparametersofthePIMisgiven.ThreekindsofIPIMsforsolvingtheDREareproposed.ThenumericalexamplesshowthattheIPIMisstableandgivesthemachineaccuracysolutions.
简介:Let{X,Xn;n≥1}beastrictlystationarysequenceofρ-mixingrandomvariableswithmeanzeroandfinitevariance,SetSn=∑^nk=1Xk,Mn=maxk≤n|Sk|,n≥1.Supposelimn→∞ES^2n/n=tα^2>0and^∞∑n=1ρ^2/d(2^n)<∞,whered=2,if-12(b+1),ifb≥0.Itisprovedthat,foranyb>-1,limε^2(b+1)ε→0^∞∑n=1(loglogn)^b/nlognP{Mn≥εσ√2nloglogn}=2/(b+1)√πГ(b+3/2)^∞∑k=0(-1)^k/(2k+1)^2b+2,whereГ(·)isaGammafunction.
简介:Throughtheanalysisoftheprinciple,errorsourcesandprecisionoftrigonometricleveling,thispaperpointsoutthekeyproblemsaboutfirstorderlevelingreplacedbytrigonometricleveling;andforthefirsttimeputsforwardthat,insomegivenconditions,itisnotonlyfeasiblebutalsovaluabletoreplacefirstorderlevelingbyprecisetrigonometricleveling,andprovesitbyexperimentationaswell.Thecontentandconclusionofthispaperhaveconsultingsignificanceandpracticablevalueforoursettingdownrelationalcriterionandproductionpractice.
简介:Theregioncompletenessofobjectdetectionisverycrucialtovideosurveillance,suchasthepedestrianandvehicleidentifications.However,manyconventionalobjectdetectionapproachescannotguaranteetheobjectregioncompletenessbecausetheobjectdetectioncanbeinfluencedbytheilluminationvariationsandclusteringbackgrounds.Inordertoovercomethisproblem,weproposetheiterativesuperpixelsgrouping(ISPG)methodtoextractthepreciseobjectboundaryandgeneratetheobjectregionwithhighcompletenessaftertheobjectdetection.First,byextendingthesuperpixelsegmentationmethod,theproposedISPGmethodcanimprovetheinaccuratesegmentationproblemandguaranteetheregioncompletenessontheobjectregions.Second,themultiresolutionsuperpixel-basedregioncompletenessenhancementmethodisproposedtoextracttheobjectregionwithhighprecisionandcompleteness.Thesimulationresultsshowthattheproposedmethodoutperformstheconventionalobjectdetectionmethodsintermsofobjectcompletenessevaluation.
简介:Considerthepositived-dimensionallatticed+(d≥2)withpartialordering≤,let{XK;K∈d+}bei.i.d.randomvari-ablestakingvaluesinarealseparableHilbertspace(H,||·||)withmeanzeroandcovarianceoperator∑,andsetpartialsumsSN=∑K≤NXK,K,N∈d+.Undersomemomentconditions,weobtainthepreciseasymptoticsofakindofweightedinfiniteseriesforpartialsumsSNasε0byusingthetruncationandapproximationmethods.TheresultsarerelatedtotheconvergenceratesofthelawofthelogarithminHilbertspace,andtheyalsoextendtheresultsof(GutandSpǎtaru,2003).
简介:医用电子直线加速器,是生物医学上一种用来对肿瘤进行放射治疗的粒子加速装置,是肿瘤外照射治疗的主要设备。目前,中国国内进口加速器主要有两种品牌:医科达和瓦里安。笔者主要探讨由瑞典医科达公司生产的医科达Precise机型,该机型在使用过程中以高压不能出束最为常见,此故障多为闸流管触发;随着技术的革新,逆向调强及容积调强技术的普及,多叶光栅(multi-leavecollimators,MLC)运动成为加速器最繁忙的部件.因此在使用过程中会出现较多的问题:医科达Precise加速器使用的是行波加速管.加速管较长.加速管真空的建立和维持都有较高要求,出现不少真空故障。笔者就上述医科达Precise机型常见三例故障的维修经验作简要分析和归纳。
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简介:山西水库地震是在最近的年,有少数的一个区域和更弱的地震里的南部的浙江省的重要地震事件。seismicity显示出一个断断续续的特征和组分发。地震网络定位的震中没证明一个占优势的方向和seismogenic结构不是清楚的。在学习,非线性的想象的波浪旅行时间方程被线性化并且解决,并且来源位置,起始的想象的速度和旅行时间剩余被获得。然后,由作为时间加倍标准差,剩余,从经度产生的最大的错误,纬度,深度和想象的速度被计算。基因人口用最大的错误被组织,地震地点的结束结果被基因算法获得。有地震大部分是的表演专注于一架在垂直附近的、向西北面向的差错飞机的这个方法的山西水库地震的重定位的结果,和在飞机和到期的北方,到期的东方和垂直方向的正常之间的包括的角度是46~,44~,并且87~分别地。结果与小地震的全面差错飞机答案的一致。地震的平均深度是4.7km,最大的深度9.5kin,和最小的深度1.7km。震中显示出向西北的狭窄的banded分布,并且焦点的深度沿着西北方向增加了。在长带的西北结束长有大约3.5km的不连续的地震差距。使用Borun模型获得的来源参数的特征不与构造地震的显著地不同。地震压力落下关于0.33MPa,并且平均压力落下是0.88MPa。根据压力掉空间分发,在长带的西北结束的地震断绝片断在一个低压力落下地区。
简介:静态、运动学的testings被使用IGS5min,30年代和5s间隔调查在精确的点放的精确卫星钟产品(PPP)答案。测试结果证明IGS卫星钟的采样率在静态的PPP答案上有很小的效果。精确卫星钟的采样间隔的所有三种类型能满足放精确性的公里厘米水平;更高的采样率没为PPP答案有重要改进。然而,卫星钟的采样率在运动学的PPP在PPP答案上有重要影响。越高卫星钟的间隔,精确性完成了越多更好。运动学的PPP的精确性完成了由用30s间隔,精确卫星钟被使用精确卫星钟和30s间隔卫星钟能几乎生产的5min间隔被将近3050%关于答案改进运动学的答案的一样的精确性。而且,从不同分析中心的精确卫星钟产品的使用可以也差不多在PPP答案上生产效果。
简介:Nonlineardynamicequationscanbesolvedaccuratelyusingapreciseintegrationmethod.Somealgorithmsexist,buttheinversionofamatrixmustbecalculatedforthesealgorithms.Iftheinversionofthematrixdoesn'texistorisn'tstable,theprecisionandstabilityofthealgorithmswillbeaffected.Anexplicitseriessolutionofthestateequationhasbeenpresented.Thesolutionavoidscalculatingtheinversionofamatrixanditsprecisioncanbeeasilycontrolled.Inthispaper,animplicitseriessolutionofnonlineardynamicequationsispresented.Thealgorithmismorepreciseandstablethantheexplicitseriessolutionandisn'tsensitivetothetime-step.Finally,anumericalexampleispresentedtodemonstratetheeffectivenessofthealgorithm.