【正文】 ation of demand and lead time uncertainties ?倉(cāng)耗 Obsolete/Dead Stock Inventories that are of little or no value due to being out of date, spoiled, damaged, etc. Types of Inventories 10 ?持久性需求 Perpetual demand Continues well into the foreseeable future ?季節(jié)性需求 Seasonal demand Varies with regular peaks and valleys throughout the year ?尖峰需求 Lumpy demand Highly variable ?規(guī)律性需求 Regular demand Not highly variable (3? Mean) ?終端需求 Terminating demand Demand goes to 0 in foreseeable future ?派生需求 Derived demand Demand is determined from the demand of another item of which it is a part Nature of Demand Accurately forecasting demand is singly the most important factor in good inventory management 11 CR (2023) Prentice Hall, Inc. ?拉動(dòng)式庫(kù)存管理法 Pull 基于每個(gè)倉(cāng)庫(kù)的特定需求以一定的訂貨批量補(bǔ)足庫(kù)存 每一個(gè)存儲(chǔ)點(diǎn)獨(dú)立 Each stocking location is considered independent 最大化控制庫(kù)存 Maximizes local control of inventories ?推動(dòng)式庫(kù)存管理法 Push 根據(jù)總需求分配產(chǎn)品到庫(kù)存點(diǎn) 鼓勵(lì)規(guī)模生產(chǎn) 準(zhǔn)時(shí)生產(chǎn)制 Justintime 同步庫(kù)存流量以滿足需求 Attempts to synchronize stock flows so as to just meet demand as it occurs 最小化庫(kù)存 Minimizes the need for inventory Inventory Management Philosophies 12 CR (2023) Prentice Hall, Inc. ?拉動(dòng)式庫(kù)存管理法 Pull Draws inventory into the stocking location Each stocking location is considered independent Maximizes local control of inventories ?推動(dòng)式庫(kù)存管理法 Push Allocates production to stocking locations based on overall demand Encourages economies of scale in production ?準(zhǔn)時(shí)生產(chǎn)制 Justintime Attempts to synchronize stock flows so as to just meet demand as it occurs Minimizes the need for inventory Inventory Management Philosophies 13 CR (2023) Prentice Hall, Inc. ?供給驅(qū)動(dòng) SupplyDriven 供應(yīng)量和時(shí)間未知 Supply quantities and timing are unknown 所有的供應(yīng)必須接受和處理 All supply must be accepted and processed 通過(guò)需求控制庫(kù)存 Inventories are controlled through demand ?聯(lián)合控制 Aggregate Control ?項(xiàng)目分類 ?項(xiàng)目組根據(jù)基于 8020法則確定的銷售水平 ?為 3個(gè)或以上的產(chǎn)品組合允許不同的庫(kù)存策略 Inventory Management Philosophies 14 Plant Warehouse 1 Warehouse 2 Warehouse 3 A 1 A 2 A 3 A = Allocation quantity to each warehouse Q = Requested replenishment quantity by each warehouse Q 1 Q 2 Q 3 Demand forecast Demand forecast Demand forecast PULL Replenish inventory with order sizes based on specific needs of each warehouse PUSH Allocate supply to each warehouse based on the forecast for each warehouse 拉動(dòng)式或推動(dòng)式庫(kù)存管理思想 Pull vs. Push Inventory Philosophies CR (2023) Prentice Hall, Inc. 911 推動(dòng)式 ——基于每個(gè)倉(cāng)庫(kù)的預(yù)測(cè)將供給分配給各個(gè)倉(cāng)庫(kù) 拉動(dòng)式 ——基于每個(gè)倉(cāng)庫(kù)的特定需求以一定訂貨批量補(bǔ)足庫(kù)存 A—將產(chǎn)品分配到各個(gè)倉(cāng)庫(kù) Q—每個(gè)倉(cāng)庫(kù)需要的補(bǔ)貨量 15 ? 多數(shù)庫(kù)存管理是針對(duì)每一種產(chǎn)品的庫(kù)存進(jìn)行控制。 39 ? EOQ模型中有一個(gè)基本假設(shè)，即任何訂貨批量都可以及時(shí)補(bǔ)進(jìn)。=???=???=zEsQDkICrQICQDSTCwhere E(z) = from a unit normal loss table at a z value of 929 48 ? 服務(wù)水平 ? =1每年產(chǎn)品缺貨件數(shù)的期望值 /年需求總量 ( ) ( )( / ) ( 39。 LTd sdsLTs ?=Caution: Can result in very high safety stock levels when leadtime variability is high 937 在需求和提前期不確定的情況下找到正態(tài)分布的標(biāo)準(zhǔn)差 s39。盤點(diǎn)后的訂貨量就是最大值（ M)與盤點(diǎn)時(shí)所持有的庫(kù)存量之差。 ) ( 39。預(yù)測(cè)時(shí)還要記錄所持庫(kù)存量，而訂購(gòu)量就等于目標(biāo)值減去所持庫(kù)存量。 78 CR (2023) Prentice Hall, Inc. Pull Methods (Cont’d) 、多地點(diǎn)的庫(kù)存管理 Multiple item, multiplelocation control The theory that has been discussed previously is useful when designing inventory control systems for the practical problem of controlling many items at many locations. Consider how a specialty chemical pany designed such a practical system. TASO（訂單積累時(shí)間） is the time to accumulate a stock order (truckload) for all items in warehouse. 79 Q1 Stock order TASO TASO LT Order received LT Q2 M 0 Quantity on hand Time M = maximum level TASO = time to accumulate stock order Qi = order quantity LT = lead time TASO ~ ~ Q3 MultipleItem, MultipleLocation Control CR (2023) Prentice Hall, Inc. 960 80 Customer Service Level For individual items The service level (stock availability) actually achieved by inventory control methods is not best represented by the probability (P) of a stockout during the lead time. It is more accurate to pute it as follows. QEsDQDEsSL zz )(39。A LTTssAthen z80%= units 579)()(30)( 39。 Given: d = 50 units/week C = $5/unit sd = 10 units/week LT = 3 weeks I = 10%/year P = S = $10/order k = $2/unit Good method for products: low value are purchased from the same vendor economies of scale in production, purchasing, and transportation 938 62 939 Q1 Stock level reviewed T T LT LT Order received Q2 M q 0 Quantity on hand Time M = maximum level最高庫(kù)存 M q = replenishment quantity補(bǔ)貨量 LT = lead time提前期 T = review interval盤點(diǎn)周期 q = quantity on hand持有庫(kù)存量 Qi = order quantity訂購(gòu)量 ~ 單一產(chǎn)品定期盤點(diǎn) Periodic Control for a Single Item 盤點(diǎn)時(shí)庫(kù)存 63 CR (2023) Prentice Hall, Inc. Estimate Q* from the EOQ formula as if under demand certainty conditions. Recall that this is Q* = 322 units. Now, T* = Q*/d = 322/50 = weeks Construct the demandduringleadtimeplusordercycletime distribution. T is order review time Periodic Review (Cont’d) 64 CR (2023) Prentice Hall, Inc. Periodic Review (Cont’d) P DD(T* + LT) X = d(T* + LT) LTTss *d39。 這可以通過(guò)將需求波動(dòng)和提前期波動(dòng)累加獲得。 ( )11 d z d zD Q s E s ESLDQ180。 ? p是生產(chǎn)速率， d是需求速率 dppICDSQ p?=2*40 CR (2023) Prentice Hall, Inc. Q*和 ROP IC2DS=*QGood method for products: 1. Of high value 2. That are purchased from one vendor or plant 3. Having few economies of scale in production, purchasing, or transportation 924 Find Q* and ROP )39。 17 ? 虛擬庫(kù)存即將自己將來(lái)所可能需要而又沒(méi)有的東西的所有相關(guān)信息建立檔案，包括品名規(guī)格價(jià)格數(shù)量等，在需要時(shí)能使用上。 “Every