简介:AthenaisthecommonframeworkusedbytheATLASexperimentforsimulation,reconstruction,andanalysis,Bydesign,Athenasupportsmultiplepersistenceservices,andinsulatesusersfromtechnology-specificpersistencedetails.AthenausersandevenmostAthenapackagedevelopersshouldneitherknownorcarewhetherdatacomefromthegridorfromlocalfilesystems.norwhetherdataresideinobjectdatabases,inROOTorZEBRAfiles,orinASCIIfiles.InthispaperwedescribehowAthenaapplicationsmaytransparentlytakeadvantageofemergingservicesprovidedbygridsoftwaretoday-howdatageneratedbyAtheajobsareregisteredingridreplicacatalogsandothercollectionmanagementservices,andthemeansbywhichinputdataareidentifiedandlocatedinagrid-awarecollectionmanagementenvironment.Weoutlineanevolutionarypathtowardincorporationofgrid-basedvirtualdataservices,wherebylocatingdatamaybereplacedbylocatingarecipeaccordingtowhichthatdtamaybegenerated.Severalimplementationscenarios,rangingfromlowlevelgridcatalogservices(e.g.,fromGlobus)throughhigher-levelservicessuchastheGridDataManagementPilot(underdevelopmentaspartoftheEuropeanDataGridporject,incollaboration,withtheParticlePhysicsDataGrid)tomoreconventionaldatabaseservices,andacommonarchitecturetosupportthesevariousscenarios,arealsodescribed.
简介:在微软的Office家庭成员中,人们对于Access2000的了解,往往中局限在它的操作界面中,对于数据库管理的功能仍只是停留在建立表、数据输入、使用本向导、数据访问页面导、报表向导、数据访问页向导等一些简单的应用上,实际上Access2000的功能十分强大,且超科一般人的想象。它是微软自公布Access后与internet结合最紧密的数据库管理软件,是一个功能非常强大,而且简单易用的数据库管理系统(DBMS),即对数据库进行存储、处理和管理的系统。
简介:Inthispaperwestudylinearsecretsharingschemesbymonotonespanprograms,accordingtotherelationbetweenrealizingaccessstructuresbylinearsecretsharingschemesandcomputingmonotoneBooleanfunctionsbymonotonespanprograms.Weconstructsomelinearsecretsharingschemes.Furthermore,westudytherearrangementsofaccessstructuresthatisveryimportantinpractice.
简介:<正>July21,1986wasanunusualdayforMexico,abigcountryinLatinAmerica.Afterpainfulchoiceandcautiousinvestigation,afterall-roundendeavorandstruggle,MexicoeventuallybecameamemberofGATT.Fromthenon,itenjoyedMost-Favored-Nationtreatmentsuchaslowertariffratesbetweenthemembers,andthefavorable-treatment
简介:ThelongtermaccessibilityofitsdataisanimportantconcernoftheDELPHIcollaboration.Itisourassumptionthatthestorageofthedataitselfwillbeaminorissueduetotheprogressinstoragetechnologies.ThereforeDELPHIfocusesonareorganisationofthedata,whichshouldprovideaflexibleandcoherentframeworkforphysicsanalysisinthefuture.ThispaperdescribesthecurrentstatusoftheIDEA(ImprovedDElphiAnalysis)projectwhichwillensureusabilityofDELPHIdataforfuturegenerationsofphysicists.
简介:Accesscontrolinmulti-domainenvironmentsisoneoftheimportantquestionsofbuildingcoalitionbetweendomains.OnthebasisofRBACaccesscontrolmodel,theconceptsofroledelegationandrolemappingareproposed,whichsupportthethird-partyauthorization.Then,adistributedRBACmodelispresented.Finallytheimplementationissuesarediscussed.
简介:TheBaBarExperimentcollectedaround20TBofdataduringitsfirst6monthsofrunning.Now,after18months,datasizeexceeds300TB,andaccordingtoprognosis,itisasmallfractionofthesizeofdatacominginthenextfewmonths,Inordertokeepupwiththedatasignificanteffortwasputintotuningthedatabasesystem,Itledtogreatperformanceimprovements,aswellastoinevitablesystemexpansion-450simultaneousprocessingnodesaloneusedfordatareconstruction.Itisbelieved,thatfurthergrowthbeyond600nodeswillhappensoon.Insuchanenvironment,manycomplexoperationsareexecutedsimultaneouslyonhundredsofmachines,puttingahugeloadondataserversandincreasingnetworktrafficIntroducingtwoCORBAservershalvedstartuptime,anddramaticallyoffloadeddatabaseservers:dataserversaswellaslockserversThepaperdescribesdetailsofdesignandimplementationoftwoserversrecentlyintroducedintheBabarsystem:conditionsOIDserverandClusteringServer,Thefirstexperienceofusingtheseserversisdiscussed.AdiscussiononaCollectionServerfordataanalysis,currentlybeingdesignedisincluded.
简介:ItypesystemmodelofCCCAM(Contention-CollisionCancellationAccessMode)isstudiedthroughmathematicalmodellingandsimulation.Therearetwoinnovations:(1)intheaccount;(2)thetimeatwhichcustomersdepartafterhavingbeenservedsuccessfullyarechosentobetheembeddedpoint,thereby"freeperiod"isintroducedreasonably.SothemathematicalmodellingandanalysisresultinthispaperaresignificantforapplicationofwirestarLANandwirelessstarLAN.