Recasting the traditional inventory model to implement just-in-time purchasing

How do you implement JIT concepts in purchasing systems that have not yet advanced to the ultimate form of JIT purchasing (where the lot size is one and the supplier delivers directly into the production floor)? Costs associated with small-lot shipments are explicitly included into the traditional EOQ model. The order quantity should first be determined based on some JIT criteria, and then the number of shipments per order should be optimized using the modified EOQ model. Guidelines and formulas are provided for carrying out these calculations to harness the advantages of JIT while moving toward more complete JIT.