228
S. Okumura et al.
Table 16.3 Parameter setting for obtaining the effect of prediction accuracy of demand and
collection
Parameter
Assigned value
K R
0 (R), 10, 50, 100
h C
0.05, 0.1 (R), 0.2
R reference condition
16.5.2 Results and Discussion
The varying rate of the total cost concerning the order interval for remanufacturing
i R is shown in Fig. 16.9. It is noted that remanufactured products are continuously
produced if the total cost for ordering interval of remanufactured products i R = 1; on
the other hand, remanufactured products are produced in lots if i R ≥ 2. The vertical
axis in Fig. 16.9 represents how much the total cost increases or decreases relative
to the total cost when the ordering interval i R is 1, which corresponds to continuous
production. The white markers in Fig. 16.9 indicate that the ordering interval that
makes the total cost minimize, which means that if white markers appear in the horizontal axis of i R ≥ 2 implying that lot production is the optimal production system;
while they appear in i R = 1 designating that continuous production is optimum. As
for all the stages, the increase/decrease rate of the total cost tends to increase as i R
grows when K R has a smaller value.
The increase/decrease rate of the total cost is negative when i R ≥ 2 in the growth
stage (a–c), which indicates that lot production is more profitable than continuous
production. As for the maturity stage (d–f), lot production is optimal depending
on h C ; however, there is little difference between continuous production and lot
production because the increase/decrease rate of the total cost is close to zero. In the
decline stage 1 and 2 (g–l), the increase/decrease rate of the total cost has the most
significant value compared to those of the growth and maturity stages as the ordering
interval for remanufacturing i R becomes large. As for the decline stage 1, continuous
production is optimal when K R = 0, 10, 50; however, lot production is optimal
when K R = 100. With regards to the decline stage 2, continuous production is
optimal when K R = 0, 10; however, lot production is optimal when K R = 50, 100.
16.6 Conclusions
This paper studies a remanufacturing system with two types of inventories: remanufactured and newly manufactured products inventory before shipment to the market,
and collected product inventory for the collected used products. We have investigated an optimal production plan minimizing the total cost by a life-cycle simulation
S. Okumura et al.
Table 16.3 Parameter setting for obtaining the effect of prediction accuracy of demand and
collection
Parameter
Assigned value
K R
0 (R), 10, 50, 100
h C
0.05, 0.1 (R), 0.2
R reference condition
16.5.2 Results and Discussion
The varying rate of the total cost concerning the order interval for remanufacturing
i R is shown in Fig. 16.9. It is noted that remanufactured products are continuously
produced if the total cost for ordering interval of remanufactured products i R = 1; on
the other hand, remanufactured products are produced in lots if i R ≥ 2. The vertical
axis in Fig. 16.9 represents how much the total cost increases or decreases relative
to the total cost when the ordering interval i R is 1, which corresponds to continuous
production. The white markers in Fig. 16.9 indicate that the ordering interval that
makes the total cost minimize, which means that if white markers appear in the horizontal axis of i R ≥ 2 implying that lot production is the optimal production system;
while they appear in i R = 1 designating that continuous production is optimum. As
for all the stages, the increase/decrease rate of the total cost tends to increase as i R
grows when K R has a smaller value.
The increase/decrease rate of the total cost is negative when i R ≥ 2 in the growth
stage (a–c), which indicates that lot production is more profitable than continuous
production. As for the maturity stage (d–f), lot production is optimal depending
on h C ; however, there is little difference between continuous production and lot
production because the increase/decrease rate of the total cost is close to zero. In the
decline stage 1 and 2 (g–l), the increase/decrease rate of the total cost has the most
significant value compared to those of the growth and maturity stages as the ordering
interval for remanufacturing i R becomes large. As for the decline stage 1, continuous
production is optimal when K R = 0, 10, 50; however, lot production is optimal
when K R = 100. With regards to the decline stage 2, continuous production is
optimal when K R = 0, 10; however, lot production is optimal when K R = 50, 100.
16.6 Conclusions
This paper studies a remanufacturing system with two types of inventories: remanufactured and newly manufactured products inventory before shipment to the market,
and collected product inventory for the collected used products. We have investigated an optimal production plan minimizing the total cost by a life-cycle simulation