供應(yīng)鏈需求預(yù)測實(shí)務(wù)-資料下載頁
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【正文】 (S1,…,S p) using procedure for static forecasting ? In period t, the forecast for future periods is given by: Ft+1 = (Lt+Tt)(St+1) and Ft+n = (Lt + nTt)St+n 38 Winter’s Model After observing demand for period t+1, revise estimates for level, trend, and seasonal factors as follows: Lt+1 = a(Dt+1/St+1) + (1a)(Lt+Tt) Tt+1 = b(Lt+1 Lt) + (1b)Tt St+p+1 = g(Dt+1/Lt+1) + (1g)St+1 a = smoothing constant for level b = smoothing constant for trend g = smoothing constant for seasonal factor 39 Winter’s Model Example: Tahoe Salt data. Forecast demand for period 1 using Winter’s model. Initial estimates of level, trend, and seasonal factors are obtained as in the static forecasting case 40 Winter’s Model L0 = 18439 T0 = 524 S1=, S2=, S3=, S4= F1 = (L0 + T0)S1 = (18439+524)() = 8913 The observed demand for period 1 = D1 = 8000 Forecast error for period 1 = E1 = F1D1 = 8913 8000 = 913 Assume a = , b=, g=。 revise estimates for level and trend for period 1 and for seasonal factor for period 5 L1 = a(D1/S1)+(1a)(L0+T0) = ()(8000/)+()(18439+524)=18769 T1 = b(L1L0)+(1b)T0 = ()(1876918439)+()(524) = 485 S5 = g(D1/L1)+(1g)S1 = ()(8000/18769)+()() = F2 = (L1+T1)S2 = (18769 + 485)() = 13093 41 預(yù)測誤差 ? 類型 ? 偏差 (bias)與隨機(jī)誤差 (random error) ? 偏差的原因 ? 未涵蓋正確之變數(shù) ? 錯(cuò)誤的變數(shù)關(guān)係 ? 錯(cuò)誤的趨勢線 ? 錯(cuò)誤的季節(jié)需求修正 ? 未發(fā)現(xiàn)的長期趨勢 42 預(yù)測誤差的衡量指標(biāo) ? Forecast error = Et = Ft Dt ? Mean squared error (MSE) MSEn = (Sum(t=1 to n)[Et2])/n ? Absolute deviation = At = |Et| ? Mean absolute deviation (MAD) MADn = (Sum(t=1 to n)[At])/n s = 43 預(yù)測誤差的衡量指標(biāo) ? Mean absolute percentage error (MAPE) MAPEn = (Sum(t=1 to n)[|Et/ Dt|100])/n ? Bias ? Shows whether the forecast consistently under or overestimates demand。 should fluctuate around 0 biasn = Sum(t=1 to n)[Et] ? Tracking signal ? Should be within the range of +6 ? Otherwise, possibly use a new forecasting method TSt = bias / MADt 44 執(zhí)行預(yù)測的建議 ? Collaborate in building forecasts ? Be sure to distinguish between demand and sales 45 協(xié)同規(guī)劃預(yù)測補(bǔ)貨模式 (Collaborative Planning, Forecasting, and Replenishment , CPFR) ? 源起 1995年， WalMart、 WarnerLambert、 SAP、Manugistics、 Benchmarking Partners等五家公司合作之零售業(yè)供應(yīng)鏈工作小組進(jìn)行之供應(yīng)商與零售商快速回應(yīng)示範(fàn)計(jì)劃 ? 共同標(biāo)準(zhǔn)協(xié)會(huì) (Voluntary Interindustry Communication Standards, VICS)以示範(fàn)計(jì)劃中有關(guān)買賣雙方合作預(yù)測市場需求內(nèi)容為基礎(chǔ)，於 1998年正式發(fā)表有關(guān)供應(yīng)鏈合作商務(wù)的規(guī)範(fàn)，以指導(dǎo)供應(yīng)商與零售商進(jìn)行協(xié)同預(yù)測與例外狀況之處理機(jī)制 ? 演進(jìn)成為 B2B電子商務(wù)中供應(yīng)鏈合作商務(wù)規(guī)範(fàn)。 46 CPFR 基本原則 零售商與供應(yīng)商間 : ? 建立一致且有效率的需求預(yù)測與規(guī)劃 ? 資訊共享與風(fēng)險(xiǎn)共擔(dān)的營運(yùn)方式 ? 交易流程整合 ? 制度化例外狀況處理 47 CPFR 主要內(nèi)容 ? 企業(yè)間商務(wù)流程定義與規(guī)範(fàn) ? NineStep Process Model ? CPFR導(dǎo)入規(guī)範(fàn) ? Roadmap of CPFR ? 績效評估指標(biāo) ? Metrics, Key Performance Indicators ? 標(biāo)準(zhǔn)商業(yè)訊息 ? CPFR XML ? CPFR XML 演講完畢，謝謝觀看！
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