简介:Inthispaper,simultaneousuniformapproximationandmeanconvergenceofquasi-HermiteinterpolationanditsderivativebasedonthezerosofJacobipolynomialsareconsideredseparately.Thedegreesofthecorrespondingapproximationsarerespectivelygivenalso.Someknownresultsareimprovedaudextended.
简介:Thegravityp-medianmodelisanimportantimprovementtothewidely-usedp-medianmodel.However,thereisstilladebateonitsvalidityinempiricalapplications.Previousstudiesevendoubtthesignificanceofthegravityp-medianmodel.UsingacasestudyoftertiaryhospitalsinShenzhen,China,thisstudyre-examinesthedifferencebetweenthegravityp-medianmodelwiththep-medianmodel,bydecomposingthedifferencebetweenthetwomodelsintogravityruleandvariantattraction.Thisstudyalsoproposesamodifiedgravityp-medianmodelbyincorporatingadistancethreshold.Theempiricalresultssupportthevalidityofthegravityp-medianmodel,andalsorevealthatonlywhentheattractionsofcandidatefacilitylocationsarevariablewillthegravityp-medianmodelleadtodifferentresultswiththep-medianmodel.Thedifferencebetweenthemodifiedgravityp-medianmodelandthegravityp-medianmodelisalsoexamined.Moreover,theimpactsofthedistance-decayparameteranddistancethresholdonsolutionsareinvestigated.Resultsindicatethatalargerdistance-decayparametertendstoresultinamoredisperseddistributionofoptimalfacilitiesandasmalleraveragetraveltime,andasmallerdistancethresholdcanbetterpromotethespatialequityoffacilities.Theproposedmethodcanalsobeappliedinstudiesofothertypesoffacilitiesorinotherareas.
简介:摘要:经济社会的发展离不开农业社会的可持续高效发展,但是农业可持续发展的大前提就是要保护环境,而不是去破坏环境来发展农业额,从而促进农业社会的发展。土壤的肥料作为决定农作物产量和质量的重要组成部分,肥料的质量和安全性会直接对于农作物产生作用,所以在实际的生产生活中也扮演着重要的角色。目前的农业经济社会的发展进程中,需要更加准确的了解和掌握肥料的选择以及使用方法,才能够解决遇到的各种问题,争取全面了解后得到对应的解决方式和方法,使得现代农业产业经济得到可持续发展。 关键词:农业可持续发展 ; 土壤肥料 ; 问题 ;