库存系统最优采购批量Witness建模与仿真

最大库存的中值； costRate (1) = 50 !每日每吨 PE的库存成本；

costRate (2) = 1000 !每次采购与运输的基本费用，包括通信费、运输基本费用； costRate (3) = 10 !每吨运输费率

!每次采购总成本=costRate(2)+costRate(3)*PurchaseBatch

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ELEMENT NAME: Customer Element Type: Part

Type:

Variable attributes Group number:

1

Inter Arrival Time: 1.0

First Arrival at: 1.0

Maximum Arrivals: Unlimited

Input / Output Rules

Output:

PUSH to CorpDoor

Actions Create: PEBatch = DayNeed ()

RecordRealValue (stockSeries,StockQty) RecordQty (5) = MeanVariable (stockSeries)

RecordQty (7) = RecordQty (5) * TIME * costRate (1) / 1000

RecordQty (9) = RecordQty (8) + RecordQty (7)

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ELEMENT NAME: PE Element Type: Part

Type:

Variable attributes Group number: 1

Maximum Arrivals: 0

Actions Create: PEBatch = PurchaseBatch SendPurchase = 0

RecordQty (4) = RecordQty (4) + PEBatch !总采购量增加

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ELEMENT NAME: CorpDoor Element Type: Buffer Quantity:

1 Capacity:

1000

Input Option: Rear Output Option:

First

Search From: Front

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ELEMENT NAME: 发货员 Element Type: Quantity: Priority: Type:

Machine 1 Lowest Single 0.1

Cycle Time:

Input / Output Rules

Input:

PULL from CorpDoor PUSH to SHIP Using Path

Output:

Actions

Start:

DIM GiveoutQty AS REAL IF StockQty < PEBatch

GiveoutQty = StockQty

RecordQty (1) = RecordQty (1) + PEBatch - GiveoutQty !缺货量增加

ELSE

GiveoutQty = PEBatch

ENDIF

StockQty = StockQty - GiveoutQty

RecordQty (3) = RecordQty (3) + GiveoutQty !消耗量增加，送出量增加 PurchasingDecision ()

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ELEMENT NAME: Road Element Type: Quantity: Priority: Type:

Conveyor 1 Lowest Queuing 10 1.0

Length: Index Time:

Maximum Capacity: 10

Input / Output Rules

Input:

IF SendPurchase = 1 PULL from PE out of WORLD Wait

ELSE

ENDIF

PUSH to SHIP

RecordQty (6) = RecordQty (6) + 1

RecordQty (8) = RecordQty (8) + PEBatch * costRate (3) / 1000 + costRate (2) StockQty = StockQty + PEBatch

Output: Join:

Actions

Front:

!下面统计是否库存超出最大库存量，如果超出，则将超出部分累加起来

IF StockQty > MaxWarnStock

RecordQty (2) = RecordQty (2) + StockQty - MaxWarnStock

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ENDIF

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ELEMENT NAME: Roadout Element Type: Path Source Element:

发货员 Destination Element: SHIP Traverse Time:

5.0 Update Interval:

0.01

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ELEMENT NAME: PEBatch Element Type: Attribute Quantity:

1

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ELEMENT NAME: costRate Element Type: Variable Quantity:

3

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ELEMENT NAME: MaxWarnStock Element Type: Variable Quantity:

1

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ELEMENT NAME: MinSafeStock Element Type: Variable Quantity:

1

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ELEMENT NAME: PurchaseBatch Element Type: Variable Quantity:

1

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ELEMENT NAME: RecordQty Element Type: Variable Quantity:

9

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ELEMENT NAME: SendPurchase Element Type: Variable Quantity:

1

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ELEMENT NAME: StockQty Element Type: Variable Quantity:

1

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ELEMENT NAME: stockSeries Element Type: Variable Quantity:

0

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ELEMENT NAME: avgStock Element Type: Function Type:

Integer Parameters:

0

Actions Execution: RETURN RecordQty (5)

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ELEMENT NAME: DayNeed Element Type: Function Type:

Integer Parameters:

0

Actions

Execution:

RETURN NORMAL (7777,1758)

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ELEMENT NAME: lostRate Element Type: Function Type:

Real Parameters:

0

Actions

Execution:

RETURN RecordQty (1) / RecordQty (3) * 100

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ELEMENT NAME: OverRate Element Type: Function Type:

Real Parameters:

0

Actions Execution:

RETURN RecordQty (2) / RecordQty (4) * 100 _____________________________________________________________

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ELEMENT NAME: PurchasingDecision Element Type: Type: Actions

Parameters:

Function Void 0

Execution: IF StockQty < MinSafeStock AND NPARTS (Road) = 0 SendPurchase = 1 !当该变量为1时，表示发出采购订单 ELSE

SendPurchase = 0 !该变量为0时，不发出采购订单

ENDIF

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ELEMENT NAME: sumCost Element Type: Function Type:

Integer Parameters:

0

Actions

Execution: RETURN RecordQty (9)

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