连续观测系统
DESCRIPTION
Soup. Soup. Soup. IP. IP. IP. Order received. Order received. Order received. Order received. Q. Q. Q. On-hand inventory. OH. OH. OH. R. Order placed. Order placed. Order placed. Time. L. L. L. TBO. TBO. TBO. Figure 10.6. 连续观测系统. IP. IP. Order received. - PowerPoint PPT PresentationTRANSCRIPT
连续观测系统连续观测系统 So
up Sou
pS
ou
p
Time
Orderreceived
Orderreceived
Q Q
OH OH
Orderplaced
Orderplaced
IP IP
TBO
L
TBO
L
TBO
L
R
Orderreceived
Q
OH
Orderplaced
IP
Orderreceived
Figure 10.6
On
-han
d i
nve
nto
ry
不确定需求不确定需求
Time
On
-han
d i
nve
nto
ry
Orderreceived
Q
OH
Orderplaced
Orderplaced
Orderreceived
IPIP
R
TBO1 TBO2 TBO3
L1 L2 L3
Q
Orderplaced
Q
Orderreceived
Orderreceived
再订货点再订货点 / / 安全库存安全库存
Average demand
during lead time
再订货点再订货点 / / 安全库存安全库存
Probability of stockout(1.0 – 0.85 = 0.15)
Cycle-service level = 85%
Average demand
during lead time
zL
R
Probability of stockout(1.0 – 0.85 = 0.15)
Cycle-service level = 85%
Average demand
during lead time
zL
R
再订货点再订货点 / / 安全库存安全库存Safety Stock/R
Safety stock = zL
= 2.33(22) = 51.3= 51 boxes
Reorder point = ADDLT + SS= 250 + 51= 301 boxes
提前期分布提前期分布t = 15
=
+
+75
Demand for week 1
75Demand for week 2
75Demand for week 3
t = 26
225Demand for
three-week lead time
t = 15
t = 15
定期观测系统定期观测系统
TimeP P
T
On
-han
d i
nve
nto
ry
定期观测系统定期观测系统
Time
On
-han
d i
nve
nto
ry
P P
T
Q1
Orderplaced
定期观测系统定期观测系统
Time
On
-han
d i
nve
nto
ry
P P
T
Q1
L
Orderplaced
定期观测系统定期观测系统
Time
On
-han
d i
nve
nto
ry
P P
T
Q1
L
Orderplaced
Orderreceived
定期观测系统定期观测系统
Time
On
-han
d i
nve
nto
ry
Orderreceived
Orderreceived
Orderplaced
Orderplaced
Q1Q2
Q3
L L LP P
T
Orderreceived
定期观测系统定期观测系统
Time
On
-han
d i
nve
nto
ry
IP1
IP3
IP2
Orderreceived
Orderreceived
IP IP
OH OH
Orderplaced
Orderplaced
Q1Q2
Q3
L L LP P
Protection interval
T
Orderreceived
IP
Time
On
-han
d i
nve
nto
ry
IP1
IP3
IP2
Orderreceived
Orderreceived
IP IP
OH OH
Orderplaced
Orderplaced
Q1Q2
Q3
L L LP P
Protection interval
T
Orderreceived
IP
定期观测系统定期观测系统
T = Average demand during the protection interval + Safety stock
= d (P + L) + zP + L
= (18 units/week)(6 weeks) + 1.28(12 units) = 123 units
EOQ = 75 units D = (18 units/week)(52 weeks) = 936 units
t = 5 units L = 2 weeks cycle/service level = 90%
Bird feeder—Calculating P and T
P = (52) = (52) = 4.2 or 4 weeksEOQ
D75
936
P+L = P + L = 5 6 = 12 units
Time
On
-han
d i
nve
nto
ry
IP1
IP3
IP2
Orderreceived
Orderreceived
IP IP
OH OH
Orderplaced
Orderplaced
Q1Q2
Q3
L L LP P
Protection interval
T
Orderreceived
IP
定期观测系统定期观测系统
EOQ = 75 units D = (18 units/week)(52 weeks) = 936 units
t = 5 units L = 2 weeks cycle/service level = 90%
Bird feeder—Calculating P and T
C = ($15) + ($45) + 15($15)4(18)
2936
4(18)
C = $540 + $585 + $225 = $1350
P = 4 weeks T = 123 units
QQ 系统和系统和 PP 系统比较系统比较P 系统
库存量补充定期进行，系统管理简单 从同一供应商订购多种物品，可以把订单合为一份采购单
只有在进行观测时，才需要了解库存状况
每种物品的观测频数可能各不相同，可减少总的订购及库存持有成本
订货批量固定，如果批量足够大，可能获得数量折扣
较低的安全库存量取得了节约的效果。
Q 系统