Single capacity constraints

Table 3.1 Major refinery capacity constraints for single refinery planning.

Table 7.1 Major capacity constraints of single refinery planning.

Gasoline is transported from one refinery to a single terminal through a pipeline or by tanker-trucks see Figure 1. The empty tanker-trucks are returned to the refinery to be reloaded for the succeeding delivery. The feasible network structures vary depending on the operating costs and capacity constraints of the pipeline and tanker-trucks. The resultant combinatorially feasible as well as feasible network structures are presented in Tables 2 and 3 for two sets of capacity constraints. 

An emergent research direction is the examination of mechanisms for decentralized allocation (for multi-item procurement) in the presence of capacity constraints at the suppliers. We discuss two mechanisms that have been proposed in the literature. Both are reverse auctions with a single buyer and multiple suppliers but differ in (i) bid structure that they support and (ii) the feedback that is provided. Both mechanisms assume that a partial allocation against a bid is acceptable to the bidders. 

Hoque, M.A. and Goyal, S.K. 2000. An optimal policy for a single-vendor singlebuyer integrated production-inventory system with capacity constraint of the transport equipment. International Journal of Production Economics, 65, 305-315. 

It pushes against two or more constraints rather than one single constraint. It can maximize the air blower and wet gas compressor capacities. 

Floudas and Grossmann (1987b) have shown that for HENs with any number of units, with or without stream splits or bypasses, and with uncertain supply temperatures and flow rates but with constant heat capacities, the active constraint strategy decomposes the resilience test (or flexibility index) problem into NLPs which have a single local optimum. Thus the resilience test (or flexibility index) also has a single local optimum solution. 

As the Excel Solver is only for single objective optimization, use the e-constrained method and the Excel Solver.xls on the CD to optimize the 4-plant IE for the two objectives as in Cases A and B. For the Solver to work reliably, number of decision variables should be limited. Thus, it is recommended to set Z21 = Z32 = 0 and Z22 = 1 = 1 for Z = a, b, c and d. This would leave the capacities of the 4 plants (Xj) as the decision variables. Treat lEvP as the constraint and vary it in the range 1.213-1.419 for Case A and 1.220-1.321 for Case B, and observe the trends of the decision variables and the objective. Do they follow similar trends as the IE for 6 plants ... 

Single objective models In Section 6.2, we presented a single objective linear programming model for order allocation using Example 6.3. The model considered supplier capacities, price discounts, buyers demand, quality, and lead-time constraints. The objective was to minimize total cost, which included fixed and variable cost of the suppliers. We shall briefly review here, some of the other single objective models that have been discussed in the literature. 

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