简介：Inthisresearch,acontent-basedimageretrieval(CBIR)systemforhighresolutionsatelliteimageshasbeendevelopedbyusingtexturefeatures.Theproposedapproachusesthelocalbinarypattern(LBP)texturefeatureandablockbasedscheme.Thequeryanddatabaseimagesaredividedintoequallysizedblocks,fromwhichLBPhistogramsareextracted.TheblockhistogramsarethencomparedbyusingtheChi-squaredistance.ExperimentalresultsshowthattheLBPrepresentationprovidesapowerfultoolforhighresolutionsatelliteimages(HRSI)retrieval.

简介：这份报纸为用BDS(BeiDou航行卫星系统)估计湿折射度地的精确论述一条新奇途径模拟仅仅，为深圳和香港GNSS的GPS，和BDS+GPS联网。模拟被把人工的噪音加到真实观察数据集执行。，而不是使用，从观点计算的d和s参数在以前的研究弄湿延期，我们采用偏爱和RMS参数，从全部的voxels的断层摄影术结果计算了，回答决心以便获得折射度的精确的更直接、全面的评估。结果显示出那：(1)湿折射度估计了独自使用BDS的tropospheric(仅仅使用的9颗卫星)的精确基本上比得上GPS的；(2)BDS+GPS(当前的操作)不能显著地改进数据为折射度断层摄影术的应用程序的空间密度；并且(3)特别地在更低的空气，折射度断层摄影术的精确的任何细微增加在中国运作的气象学的服务上为任何应用依赖者忍受大意义。

简介：Aseachtypeofsatellitenetworkhasdifferentlinkfeatures,itsdatatransmissionmustbedesignedbasedonitslinkfeaturestoimprovetheefficiencyofdatatransferring.Thetransmissionofnavigationintegratedservicesinformation(NISI)inaglobalnavigationsatellitesystem(GNSS)withinter-satellitelinks(ISLs)isstudiedbytakingtherealsituationofinter-satellitecommunicationlinksintoaccount.Anon-demandcomputingandbufferingcentralizedroutestrategyisproposedbasedondynamicgroupingandthetopologyevolutionlawoftheGNSSnetworkwithinwhichthesatellitenodesareoperatedinthemannerofdynamicgrouping.Dynamicgroupingisbasedonsatellitesspatialrelationshipsandthegrouproleofthesatellitenodechangesbyturnsduetoitsspatialrelationships.Theroutestrategyprovidessignificantadvantagesofhighefficiency,lowcomplexity,andflexibleconfiguration,bywhichtheestablishedGNSScanpossessthefeaturesandcapabilitiesoffeasibledeployment,efficienttransmission,convenientmanagement,structuralinvulnerabilityandflexibleexpansion.

简介：Animprovedabsolutecalibrationtechnologybasedonindirectmeasurementswasdevelopedthroughtwoprobativeexperiments,theperformanceofwhichwasevaluatedbyapplyingtheapproachtoinsituseasurfaceheight(SSH)attheTianhengIsland(tidalgauge)andthesatellitenadir(GPSbuoy).UsingGeoid/MSS(meanseasurface)data,whichaccountedforaconstantoffsetbetweennadirandonshoretidalgaugewaterlevels,andTMD(tidalmodeldriver),whichcanceledoutthetime-varyingoffsets,nadirSSH(seasurfaceheight)couldbeindirectlyacquiredatanonshoretidalgaugeinsteadoffromdirectoffshoreobservation.TheapproachextrapolatedtheonshoreSSHouttotheoffshorenadirwithanaccuracyof(1.88±0.20)cmandastandarddeviationof3.3cm,whichsuggestedthattheapproachpresentedwasfeasibleinabsolutealtimetercalibration/validation(Cal/Val),andtheapproachenormouslyfacilitatedtheobtainingSSHfromtheoffshorenadir.

简介：Remote-sensingdataforprotectedareasinnorthernTogo,obtainedinthreedifferentyears(2007,2000,and1987),wereusedtoassessandmapchangesinlandcoverandlanduseforthisdroughtpronezone.Thenormalizeddifferencevegetationindex(NDVI)wasappliedtotheimagestomapchangesinvegetation.Anunsupervisedclassification,followedbyclassesrecoding,filtering,identifications,areacomputingandpost-classificationprocesswereappliedtothecompositeofthethreeyearsofNDVIimages.Maximumlikelihoodclassificationwasappliedtothe2007image(ETM+2007)usingasupervisedclassificationprocess.Sevenvegetationclassesweredefinedfromtrainingdatasets.Thesevenclassesincludedthefollowingbiomes:riparianforest,dryforest,floodedvegetation,woodedsavanna,fallows,parkland,andwater.Fortheseclasses,theoverallaccuracyandtheoverallkappastatisticfortheclassifiedmapwere72.5%and0.67,respectively.Dataanalysesindicatedagreatchangeinlandresources;especiallybetween1987and2000probablyduetotheimpactofdemocratizationprocesssocial,economic,andpoliticaldisorderfrom1990.Wide-scalelossofvegetationoccurredduringthisperiod.However,areasofvegetationclearingandregrowthweremorevisiblebetween2000and2007.Themainsourceofconfusioninthecontingencymatrixwasduetoheterogeneitywithincertainclasses.Itcouldalsobeduetospectralhomogeneityamongtheclasses.Thisresearchprovidesabaselineforfutureecologicallandscaperesearchandforthenextmanagementprograminthearea.