供应链中的需求和供给规划.ppt

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1、2供应链中的需求和供给规划2.1供应链需求预测预测是供应链中战略性和规划性决策的基础Strategyordesign:ForecastPlanning:ForecastOperationActualdemand供应链“推动阶段”的决策也以需求预测为基础生产:日程安排,库存管理,总体计划营销:销售资源配置,促销,新产品开发财务:生产线（设备）的投资和预算规划人事:雇员计划,雇佣,解雇预测的特征预测经常会出错，在供应链规划中必须考虑预测误差(或者需求的不确定性)。长期预测通常没有短期预测精确。综合预测通常要比独立预测准确得多，因为综

2、合预测相对于均值的标准差较预测的基本步骤理解预测的目的。将需求规划和预测结合起来。识别影响需求预测的主要因素。理解和识别顾客群。决定采用何种最适当的预测方法。决定预测的实施和选择计算误差的方法。预测方法Qualitative定性预测方法TimeSeries时间序列方法StaticAdaptiveCausal因果关系法Simulation模拟法被考察需求的构成被考察需求(O)=系统需求(S)+随机需求(R)Level(currentdeseasonalizeddemand)Trend(growthordeclineindemand

3、)Seasonality(predictableseasonalfluctuation)=需求水平×需求趋势×季节性需求(复合型)=level+trend+seasonalfactor(附加型)=(level+trend)×seasonalfactor(混合型)TimeSeriesForecastingForecastdemandforthenextfourquarters.QuarterlyDemandforNaturalGas.comQuarterlyDemandatNaturalGas.comForecastingmeth

4、odsStaticAdaptiveMovingaverageSimpleexponentialsmoothingHolt’smodel(withtrend)Winter’smodel(withtrendandseasonality)StaticMethodsSteps:DeseasonalizedemandandrunlinearregressiontoestimatelevelandtrendEstimateseasonalfactorsDefinitions:Deseasonalizeddemand:representsth

5、edemandthatwouldhavebeenobservedintheabsenceofseasonalfluctuations.Theperiodidtypisthenumberofperiodsafterwhichtheseasonalcyclerepeatsitself.MovingaverageIsappropriatewhendemandhasnoobservabletrendorseasonalitySystematiccomponentofdemand=levelEquationforanN-periodmov

6、ingaverageLt=(Dt+Dt-1+…+Dt-N+1)/NFt+1=LtExampleSimpleExponentialSmoothingIsappropriatewhendemandhasnoobservabletrendorseasonalitySystematiccomponentofdemand=levelEquationExampleTrend-CorrectedExponentialSmoothing(Holt'sModel)Isappropriatewhendemandisassumedtohaveale

7、velandatrendinthesystematiccomponentbutnoseasonalitySystematiccomponentofdemand=level+trendEquationExampleTrend-andSeasonality-CorrectedExponentialSmoothing(Winter'sModel)isappropriatewhenthesystematiccomponentofdemandisassumedtohavealevel,trend,andseasonalfactor.Sys

8、tematiccomponentofdemand=(level+trend)×seasonalfactorEquationExampleSummaryForecastingMethodApplicabilityMovingaverageDemanddisplay