简介:
简介:AftertheendoftheColdWar,therehaveemergedaseriesofnewsignificantphenomenaininternationalrelations.First,asaresultofthecollapseoftheformerSovietUnionandthedisintegrationoftheWarsawTreatyOrganization,thereisnolongeracommonenemyforWesternEuropeandtheUS.Second,con-
简介:In2011,Chanproposedanimageauthenticationmethodbyproducingtheparitycheckbitsfrompixelswhosebitshavebeenrearranged.Duetothisrearrangement,thevalueofthemost-significantbitofeachtamperedpixelcanbedeterminedaccordingtoitsparitycheckbits.Withthehelpofthemost-significantbitofthepixel,thepixelcanberecoveredbyselectingtwopossible(7,4)Hammingcodewords.However,ifthedistancebetweentwoHammingcodewordsiswithinacertainrange,incorrectselectionmayoccur.Chan'smethodaddedoneadditionalbittoindicatethecorrectone.Itistrivialthatthismaydegradethequalityoftheauthenticatedimage.Inthispaper,wegroupfourmost-significantbitsintodifferentgroupstoformamappingcodebookandthemappingcodebookisusedtoproduceauthenticationdatainsteadofthe(7,4)Hammingcodebook.Theexperimentalresultsshowthattheproposedmethodhasagreaterabilitytorecovertamperedareas.
简介:Weexploredthepossibilitiesofwhole-genomeduplication(WGD)inprokaryoticspecies,whereweperformedstatisticalanalysesoftheconfigurationsofthecentralanglesbetweenhomologoustandemrepeats(TRs)onthecircularchromosomes.Atfirst,wedetectedTRsontheirchromosomesandidentifiedequivalenttandemrepeatpairs(ETRPs);here,anETRPisdefinedasapairoftandemrepeatssequentiallysimilartoeachother.ThenwecarriedoutstatisticalanalysesofthecentralangledistributionsofthedetectedETRPsoneachcircularchromosomebywayofcomparisonsbetweenthedetecteddistributionsandthosegeneratedbynullmodels.Intheanalyses,weestimatedaPvaluebyasimulationusingtheKullback–Leiblerdivergenceasadistancemeasurebetweentwodistributions.Asaresult,thecentralangledistributionsfor8outofthe203prokaryoticspeciesshowedstatisticallysignificantdeviations(P<0.05).Inparticular,wefoundoutthecharacteristicfeatureofoneroundofWGDinPhotorhabdusluminescensgenomeandthatoftworoundsofWGDinEscherichiacoliK12.
简介:Inthispaper,weanalyzedtheOneFoundationsreliefandreconstructionactivitiesaftertheYaanearthquake.TheanalysisshowsthattheparticipationofNGOsindisasterreliefactivitieshasundergonedifferentstages.IntheJiujiangearthquake,NGOsparticipationwasintherudimentarystage.IntheWenchuanearthquake,theybecameoneoftheactiveparticipants.IntheYaanearthquake,theyplayedanactiverolethroughacooperationmechanism.ThatmeansNGOshavehadthecapabilityofresourcemobilizationandcooperationwiththemwillimprovedisastermanagementcapacities,especiallyinthenationalsignificantseismicmonitoringandprotectionregions.
简介:Forpredictionoftheextremesignificantwaveheightintheoceanareaswherelongtermwavedataarenotavailable,theempiricalmethodofextrapolatingshorttermdata(1~3years)isusedindesignpractice.Inthispapertwomethodsareproposedtopredictextremesignificantwaveheightbasedonshort-termdailymaxima.AccordingtothedaarecordedbytheOceanographicStationofLiaodongBayattheBohaiSea,itissupposedthatdailymaximumwaveheightsarestatisticallyindependent.Thedatashowthatdailymaximumwaveheightsobeylog-normaldistribution,andthatthenumbersofdailymaximavaryfromyeartoyear,obeyingbinomialdistribution.Basedonthesestatisticalcharacteristics,thebinomial-log-normalcompoundextremumdistributionisderivedforpredictionofextremesignificantwaveheights(50~100years).Forexaminationofitsaccuracyandvalidity,thepredictionofextremewaveheightsisbasedon12years′dataatthisstation,andbasedoneach3years′datarespectively.Theresultsshowthatwithconsiderationofconfidenceintervals,thepredictedwaveheightsbasedon3years′dataareveryclosetothosebasedon12years′data.TheobserveddatainsomeoceanareasintheAtlanticOceanandtheNorthSeashowitisnotcorrecttoassumethatdailymaximumwaveheightsarestatisticallyindependent;theyaresubjecttoMarkovchaincondition,obeyinglog-normaldistribution.Inthispaperananalyticalmethodisderivedtopredictextremewaveheightsinthesecases.AcomparisonofthecomputationsshowsthatthedifferencebetweentheextremewaveheightsbasedontheassumptionthatdailymaximaarestatisticallyindependentandthattheyaresubjecttoMarkovChainconditionissmallerthan10%.
简介:Overthepastfewdecades,extremechangeshaveoccurredinthecharactersofexploitedfishpopulations.Themajorityofthesechangeshaveaffectedthegrowthtraitsoffishlifehistory,whichincludeasmallersize-at-age,anearlierage-at-maturationandamongothers.Currently,thecausesoftheselifehistorytraitschangesstillrequiresystematicanalysesandempiricalstudies.Theexplanationsthathavebeencitedaremerelyexpressedintermsoffishphenotypicadaptation.Ithasbeenclaimedthattheoriginaltraitsoffishcanberecoveredoncetheintensityofexploitationofthefishiscontrolled.Sustainedenvironmentalandfishingpressurewillchangethelifehistorytraitsofmostfishspecies,sothefishindividual’straitsarestillinsmallsize-at-ageandatearlierage-at-maturationinexploitedfishpopulations.Inthispaper,weexpressedourviewofpointsthatfishinggearhasimposedselectivityonfishpopulationsandindividualsasvariousotherenvironmentalfactorshavedoneandsuchchangesareunrecoverable.Accordingtotheexistingtendofexploitedfishindividual’slifehistorytraits,wesuggestedfurtherresearchesinthisfieldandprovidedbettermethodsoffisherymanagementandtherebyfisheryresourcesprotectionthanthoseavailableearly.
简介:TherapidpopulationgrowthhasbeenamajorproblemofBeijing.Itaffectedontransportation,schoolingandhousing.On26thSeptember2011,BeijingPopulationandFamilyPlanningCommissionannouncedthattheywoulddraftpopulationassessmentprovisions.Governmentpolicieswouldbeissuedaccordingtopopulationplansforassessingtheireffectsonpopulationcontrol.