英文笔试题.docx

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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