学科分类
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3 个结果
  • 简介:Nonlinearmixedeffectsmodel(NLMEM)isbuiltontherelationshipofthefixedandrandomeffectsintheregressionfunction.TheNLMEMhasanobviouscomparativeadvantageinanalyzingthelongitudinaldata,repeatedmeasuresdataandmultileveldata.Two-levelNLMEMisusedtoanalyzethedominantheightforChinesefir(Cunninghamialanceolata).Theauthorsoutlinethetwo-levelNLMEMandintroducetheparametersestimationmethodofthemodel.BasedonfivecommonRichardandLogisticmodels,themixedmodelisbuilt.Themodelingdataareusedtocalculateandcomparewith19modelsderivedfromeachbasedmodel,and5optimalmixedmodelsarebuilt.Comparedthe5optimalmixedmodelswithtraditionalregressionmodels,itisshowedthatthetwo-levelNLMEMhasabetterfittingeffectthantheregressionmodel.

  • 标签: TWO-LEVEL nonlinear MIXED effects MODEL DOMINANT
  • 简介:Basedonamultilevellinearmixedmodelapproach,anindividualdiameterincrementmodelwasdevelopedforfirplantationtreesgrowinginJiangxiProvince.Thedatasetusedinthisstudycamefromlong-termpermanentresearchplots.Thedatabaseconsistsoftotalof82counties,365plots,5416treesand16248observations.Thepaperchosemixedeffectsmodelsinsteadofregressionanalysisapproachbecauseitallowsforpropertreatmentoferrortermsandcorrelationinarepeatedmeasuresanalysisframework.Themodelwasdefinedasamixedlinearmodelwithparameterrandomeffectofplot,areaorplotandareasimultaneous.Inadditiontheheteroscedasticityandcorrelationwastakenintoaccount.Mixedmodelcalibrationofdiameterincrementwascarriedoutwiththeindependentdatausingadifferentsampleofcomplementaryobservations.Theresultshowedthatthetotalstandbasalarea,thediameteroftargettrees,theratioofbasalareaoflargertreestotargettreediameter,andaltitudewerefoundtobesignificantpredictors.Boththefittingmodelandthecalibratedmodelmeanasubstantialimprovementcomparedwiththeclassicalapproachwidelyusedinforestmanagement.Aftertakingintoaccountreasonablevariancefunctionofheteroscedasticityandcorrelation,themodelshowsbetterofgoodnessoffitthanonlytakingintoaccountparameterrandomeffects.Thistypeofmodelingmethodologyshowsflexible,preciseandaccurate.

  • 标签: INDIVIDUAL diameter INCREMENT HETEROSCEDASTICITY correlation structure
  • 简介:从一个螺丝钉出版社的米饭糠蛋糕或分泌物的外观对应于在抽取过程生产的油的水平。在操作背景,油抽取水平和蛋糕外观之间的关系被学习。蛋糕特征可靠地显示期望的油恢复抽取水平。这些结论适用于两Chainat1米饭糠和parboiled米饭糠。变量是螺丝钉出版社(在从8.5~19.8r/min的五个层次的集合)和在螺丝钉和桶(在1.0和1.9厘米之间的集合)之间的相应清理距离的速度。结果证明抽取的最大的层次为米饭糠是4.17%并且8.20%为parboiled米饭糠。在最大的抽取水平,仪器连续地解除了难的蛋糕,易碎,片状,在一个方面上晴朗、擦亮却在其它上迟钝、粗糙。

  • 标签: 螺旋压力机 操作设置 提取过程 米糠油 外观 采水