Glossary · approach
Power-of-Two Policy
In multi-product shared-setup inventory systems, restricting each product's order period to powers of two of a base period T (T, 2T, 4T, ...) yields a solution within 2% of the true optimum and is field-schedulable (Roundy 1985).
Power-of-TwoInteger-Ratio PolicyRoundy Policy98-Percent-Effective Policy
Power-of-Two Policy is the family of policies introduced by Roundy (1985) for multi-product shared-setup inventory systems and one-warehouse-multi-retailer (OWMR) systems. The per-product order period is restricted to T_i = 2^k × T, where T is a base period and k is a non-negative integer chosen per product. Roundy's theorem: the best solution under this restriction is within 2% of the unrestricted theoretical optimum, i.e. guaranteed at most 2% sub-optimal (the well-known 98%-effective result). The practical payoff is **schedulability**: the power-of-two period structure makes the calendar deterministic — at every integer multiple of T it is fixed which products are jointly ordered, allowing consistent sharing of one truck, one customs filing, one supplier-order opening. The policy is widely applied in the Joint Replenishment Problem (JRP), OWMR distribution systems and broader multi-echelon supply-chain coordination. Atkins and Iyogun (1988) develop a stochastic extension; Muckstadt and Roundy (1993) provide a survey.
Örnek
A distributor with 8 main suppliers chooses base period T = 1 week and assigns each of 200 SKUs a power-of-two multiplier (m_i in {1, 2, 4, 8, 16}); the exact weeks in which each SKU is ordered are then deterministic and truck-fill becomes predictable.