英文笔试题.docx
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英文笔试题
一、
TheSaccharomycesGenomeDatabaseascientificdatabaseofthemolecularbiologyandgeneticsoftheyeastSaccharomycescerevisiae,hasrecentlydevelopedseveralnewresourcesthatallowthecomparisonandintegrationofinformationonagenome-widescale,enablingtheusernotonlytofinddetailedinformationaboutindividualgenes,butalsotomakeconnectionsacrossgroupsofgeneswithcommonfeaturesandacrossdifferentspecies.TheFungalAlignmentViewerdisplaysalignmentsofsequencesfrommultiplefungalgenomes,whiletheSequenceSimilarityQuerytooldisplaysPSI-BLASTalignmentsofeachS.cerevisiaeproteinwithsimilarproteinsfromanyspecieswhosesequencesarecontainedinthenon-redundant(nr)proteindatasetatNCBI.TheYeastBiochemicalPathwaystoolintegratesgroupsofgenesbytheircommonrolesinmetabolismanddisplaysthemetabolicpathwaysinagraphicalform.Finally,theFindChromosomalFeaturessearchinterfaceprovidesaversatiletoolforqueryingmultipletypesofinformationinSGD.
二、
TheCambridgeStructuralDatabase(CSD)nowcontainsdataformorethanaquarterofamillionsmall-moleculecrystalstructures.TheinformationcontentoftheCSD,togetherwithmethodsfordataacquisition,processingandvalidation,aresummarized,withparticularemphasisonthechemicalinformationaddedbyCSDeditors.Nearly80%ofnewstructuraldataarriveselectronically,mostlyinCIFformat,andtheCCDCactsastheofficialcrystalstructuredatadepositoryfor51majorjournals.TheCCDCnowmaintainsbothaCIFarchive(morethan73000CIFsdatingfrom1996),aswellasthedistributedbinaryCSDarchive;theavailabilityofdatainbotharchivesisdiscussed.AstatisticalsurveyoftheCSDisalsopresentedandprojectionsconcerningfutureaccessionratesindicatethattheCSDwillcontainatleast500000crystalstructuresbytheyear2010.
三、
Manysoftwaresystemsdonothaveadocumentedsystemarchitecture.Theseareoftenlarge,complexsystemsthataredifficulttounderstandandmaintain.Oneapproachtorecoveringtheunderstandingofasystemistoextractarchitecturaldocumentationfromthesystemimplementation.Toevaluatetheeffectivenessofthisapproach,weextractedarchitecturaldocumentationfromtheLinuxTMkernel.TheLinuxkernelisagoodcandidateforacasestudybecauseitisalarge(800KLOC)systemthatisinwidespreaduseanditisrepresentativeofmanyexistingsystems.OurstudyresultedindocumentationthatisusefulforunderstandingtheLinuxsystemstructure.Also,welearnedseveralusefullessonsaboutextractingasystem'sarchitecture
四、
TheenormousconsumermarketforIBMPCsandcompatibleshasmadethemaffordable.Now,withafreeoperatingsystemcalledLinux,theseinexpensivemachinescanbeconvertedintopowerfulworkstationsforteaching,research,andsoftwaredevelopment.Linuxisafull-fledgedoperatingsystemthatprovidesallthecapabilitiesnormallyassociatedwithcommercialUnixsystemsandhasexcellentcompilersforC,C++,Pascal,Modula-2and-3,Oberon,Smalltalk,andFortran.ForprofessionalswhouseUnix-basedworkstationsatwork,Linuxpermitsvirtuallyidenticalworkingenvironmentsontheirpersonalhomemachines.Forcost-consciouseducationalinstitutions--especiallyindevelopingnations--Linuxcancreateworld-classcomputingenvironmentsfrominexpensive,easilymaintainedPCclones.And,foruniversitystudents--especiallyinscienceandengineering--Linuxprovidesanessentiallycost-freepathintoUnixandXWindows.Untilrecently,mostinformationaboutLinuxwasfoundonlyontheInternet.Thisarticleattemptstoremedythatsituationbydescribinghowtoobtain,install,anduseLinux,aswellasthehardwarerequirementstorunit.Inadditiontoprovidingasurveyofpertinentliterature,thearticledescribesseveralpublic-domainapplicationsthattheauthorhasfounduseful.
五、
Westudywaveletfunctionestimationviatheapproachofblockthresholdingandidealadaptationwithoracle.Oracleinequalitiesarederivedandserveasguidesfortheselectionofsmoothingparameters.Basedonanoracleinequalityandmotivatedbythedatacompressionandlocalizationpropertiesofwavelets,anadaptivewaveletestimatorfornonparametricregressionisproposedandtheoptimalityoftheprocedureisinvestigated.Weshowthattheestimatorachievessimultaneouslythreeobjectives:
adaptivity,spatialadaptivityandcomputationalefficiency.Specifically,itisprovedthattheestimatorattainstheexactoptimalratesofconvergenceoverarangeofBesovclassesandtheestimatorachievesadaptivelocalminimaxrateforestimatingfunctionsatapoint.Theestimatoriseasytoimplement,atthecomputationalcostof$O(n)$.Simulationshowsthattheestimatorhasexcellentnumericalperformancerelativetomoretraditionalwaveletestimators.
六、
AMIRIXEmbeddedLinuxisconfigurable,stable,reliableandfullysupported.Itisderivedfromstandard,opensourceLinuxandhasbeentailoredthroughtheadditionofhardwarespecificdevicedrivers,andapplicationleveltools,toprovideastable,reliableandfullysupportedoperatingsystem.Aswell,AMIRIXprovidesvalidated,documented,andsupportedembeddedLinuxreleases.AMIRIXEmbeddedLinuxcanbeusedinsuchthingsasInternetinfrastructure,consumerdevices,retailbusinessproducts,andtransportationsystems.
BenefitsofAMIRIXEmbeddedLinux...
∙StandardLinuxkernelprovidedwithsourcecode
∙DebianGNU/Linuxbasedtargetoperatingsystem
oFullyoptimized,tailoredsupport
∙Trulyembedded
oFlashbased,disklessoperation
oHeadlesssupport
oSmallfootprint
∙Nativeandcrossdevelopmenthostsupport
oNativeSBCbased
oIntelPCbased--Linux
∙Comprehensive,user-friendlymanualtogetyouupandrunningquickly
∙Professionalsupportoptionsavailable
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