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简介：Asystematic,efficientcompilationmethodforqueryevaluationofDeductiveDatabases(DeDB)isproposedinthispaper.Inordertoeliminateredundancyandtominimizethepotentiallyrelevantfacts,whicharetwokeyissuestotheefficiencyofaDeDB,thecompilationprocessisdecomposedintotwophases.Thefirstisthepre-compilationphase,whichisresponsiblefortheminimizationofthepotentiallyrelevantfacts.Thesecond,whichwerefertoasthegeneralcompilationphase,isresponsiblefortheeliminationofredundancy.Therule/goalgraphdevisedbyJ.D.Ullmanisappropriatelyextendedandusedasauniformformalism.Twogeneralalgorithmscorrespondingtothetwophasesrespectivelyaredescribedintuitivelyandformally.

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简介：Aconceptualleveldatabaselanguagefortheentityrelationship(ER)modelimplicitlycontainsintegritiesbasictoERconceptsandspecialretrievalsemanticsforinheritancesofattributesandrelationships.Prolog,whichbelongstothelogicalandphysicallevel,cannotbeusedasafoundationtodirectlydefinethedatabaselanguage.ItisshownhowPrologcanbeenhancedtounderstandtheconceptsofentities,relationships,attributesandis-arelationships.TheenhancedPrologisthenusedasafoundationtodefinethesemanticsofadatabasequerylanguagefortheERmodel.Thethreebasicfunctionsofmodelspecification,updatesandretrievalsaredefined.

简介：Theconstructionofoceanographicontologiesisfundamentaltothe'digitalocean'.Therefore,onthebasisofintroductionofnewconceptofoceanographicontology,anoceanographicontology-basedspatialknowledgequery(OOBSKQ)methodwasproposedanddeveloped.Becausethemethodusesanaturallanguagetodescribequeryconditionsandthequeryresultishighlyintegratedknowledge,itcanprovideuserswithdirectanswerswhilehidingthecomplicatedcomputationandreasoningprocesses,andachievesintelligent,automaticoceanographicspatialinformationqueryonthelevelofknowledgeandsemantics.Acasestudyofresourceandenvironmentalapplicationinbayhasshowntheimplementationprocessofthemethodanditsfeasibilityandusefulness.

简介：Approximatequeryprocessinghasemergedasanapproachtodealingwiththehugedatavolumeandcomplexqueriesintheenvironmentofdatawarehouse.Inthispaper,wepresentanovelmethodthatprovidesapproximateanswerstoOLAPqueries.Ourmethodisbasedonbuildingacompressed(approximate)datacubebyaclusteringtechniqueandusingthiscompresseddatacubetoprovideanswerstoqueriesdirectly,soitimprovestheperformanceofthequeries.WealsoprovidethealgorithmoftheOLAPqueriesandtheconfidenceintervalsofqueryresults.AnextensiveexperimentalstudywiththeOLAPcouncilbenchmarkshowstheeffectivenessandscalabilityofourcluster-basedapproachcomparedtosampling.

简介：Inmanyapplicationsanddomains,temporalconstraintsbetweenactions,andtheirprobabilitiesplayanimportantrole.Weproposethefirstapproachintheliteraturecopingwithprobabilisticquantitativeconstraints.Toachievesuchachallenginggoal,weextendthewidelyusedsimpletemporalproblem(STP)frameworktoconsiderprobabilities.Specifically,weproposei)aformalrepresentationofprobabilisticquantitativeconstraints,ii)analgorithm,basedontheoperationsofintersectionandcomposition,forthepropagationofsuchtemporalconstraints,andiii)facilitiestosupportqueryansweringonasetofsuchconstraints.Asaresult,weprovideuserswiththefirsthomogeneousmethodsupportingthetreatment(representing,reasoning,andquerying)ofprobabilisticquantitativeconstraints,asrequiredbymanyapplicationsanddomains.

简介：这篇论文提供复合条件质问(CCQ)和基于空格从踪迹代数学导出的踪迹信息使用要求引导的一个形式化方法的应用程序问题的一个形式化的定义。与解决CCQ的应用程序问题的形式化的进程，CCQ的申请的正式要求说明被给，一形式化，到正式要求说明的要求引导的结果的自动印射被执行，软件系统模型和应用程序代码被开发。通过住房信息上的全面质问的一个样品应用程序，可行性形式化，为CCQ的应用程序问题的自动软件开发被证明。结果关于形式化和自动软件开发为另外的问题有重要含意。

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简介：ThePowerSystemDepartment(PSD)isthelargestpro-fessionalresearchanddevelopmentorganizationoncomprehensivepowersystemplanning,engineeringandoperationoftheElectricPowerResearchInstitute(EPRI)oftheMinistryofEnergy.TheactiveRD&EofPSDarecomposedofthefollowingfivemajorareas.Powersystemanalysis,softwaredevelopment&application,automaticdevices,DCtransmission,generation&transmissioncommission,modernlaboratoriesforRD&Eandelectricalappara-

简介：微笑，也许是人类最简单却最有力量的一种表情。微笑是盛开在脸上的花朵，是一个人能够献给其他人的一份礼物。当你的嘴角浮现一个优美的弧度时，你是否会感觉到世界增添了一丝光明？你的心中是否会荡漾起层层温馨的涟漪？一个淡淡的微笑，会给人一种微风掠过的清爽；一个会心的微笑，会让人心中开出一朵美丽而温暖的花朵。一个人经常友好地对别人微笑，

简介：看看这些种子都长成了什么样鲜花。

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简介：Knowledgeispower。（知识就是力量。）这句话是英国的哲学家、思想家、作家弗朗西斯·培根（FrancisBacon）说的。意为知识能充实提高、完善自己.有关知识的谚语很多。如：

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简介：这篇论文尽最大努力涉及停电的机制从自我组织的criticality的观点的系统。由使用放大窗口变化(SWV)和重新可伸缩的范围统计(R/S)的二个评价算法，这篇论文尽最大努力学习停电数据系统在1988-1997期间。停电数据of1994-1997与自相关与一致很好的分析表演的结果。而且，停电概率对停电尺寸的功能展出幂定律分发，这被发现。

简介：Withthedevelopmentofcleanenergy,switchinganddistributionissuesinaphotovoltaicsystemaregettingmuchattentioninrecentyears.ThispaperdesignsaDCtoACinverterandpowerswitchinganddistributionsystembetweenasolarpowersystemandthemunicipalsystembyusingtheDarlingtonamplifierstructurewiththephotosensitiveresistorandaccompanyingrelays,anddetailsthesystemcircuits.Theproposedsystemcanachieveastableoutputof110VAC,aswellasself-generatingdrivingvoltageandswitchingbetweenthemunicipalelectricalsystemandthesolarpowersystem.Themathematicanalysisandactuallytestresultsdemonstratethattheproposedmethodisaneasy,inexpensive,andlowcostwaytobuildasolarpowerswitchinganddistributionsystem.