Inventory aggregation

Impact category/ aggregated inventory data Source Short description Examples... 

Retailers such as Gap also use information centralization effectively. If a store does not have the size or color that a customer wants, store employees can use their information system to inform the customer of the closest store with the product in inventory. Customers can then either go to this store or have the product delivered to their house. Gap thus uses information centtal-ization to virtually aggregate inventory across all retail stores even though the inventory is physically separated. This allows Gap to reduce the amount of safety inventory it carries while providing a high level of product availability. 

In both cases, exploiting substitution allows the supply chain to satisfy demand using aggregate inventories, which permits the supply chain to reduce safety inventories without hurting product availability. In general, given two products or components, substitution may be oneway (i.e., only one of the products [components] substitutes for the other) or two-way (i.e., either product [component] substitutes for the other). We briefly discuss one-way substitution in the context of manufacturer-driven substitution and two-way substitution in the context of customer-driven substitution. 

EXAMPLE 14-3 Trade-Offs When Aggregating Inventory... 

Wallace TF (ed) (1992) APICS Dictionary, 7th edn. American Production and Inventory Control Society, Falls Church VA Wang R, Liang T (2004) Application of fuzzy multi-objective linear programming to aggregate production planning. Computers Industrial Engineering 46 17-41... 

Grade efficiency data are usually derived from experimental trials which provide sufficient information to allow the material balance to be closed for particles of all sizes. Sufficient information for determination of G(d) is provided by a combination of any three of the following four system properties E, Ff(d), Fu(d), F0(d), the remaining property being determined by the material balance. Size distribution data for primary particles, rather than floes or aggregates, are required for the inventory. 

The known number of mineral deposits worked in Ireland runs to several hundred. It would be impractical to include every site in the inventory, especially as the inventory has to include aggregate and stone operations as well. Indeed, another Member State (Italy) has records of over 20,000 stone operations and over 3,000 metal mines. 

A similar report is required of any facility with MSDS requirements under OSHA for hazardous chemicals. It must submit one of two different emergency and hazardous chemical inventory forms. Tier I provides aggregate information on each hazardous chemical with the type of health and physical hazards it presents and the estimates of daily quantities at the facility (maximum and average daily amounts). Tier II is the most complete report and contains all information provided in Tier I. It is commonly preferred by government agencies and includes chemical-specific information, such as the following ... 

Depending on the requirements of the operation, this system may also include breakdown or aggregation of inventory received into smaller or larger stock keeping units (SKUs) for onward distribution. It may also include interfaces to purchase order systems, labeling applications, automated materials handling systems such as sortation systems, stock location systems, automated storage and retrieval systems. Radio Data Terminals (RDTs), Radio Frequency Identihcation units... 

From Eq. (12-5), we then find that X g — rio(Xi/ X )". Since no is large, it follows that as X increases, X will remain very small until X approaches X, and then X g will grow rapidly. Since X is a mole fraction, it cannot exceed unity, and therefore X must remain less than X. Hence, as the total inventory of surfactant increases from zero, most of it remains isolated as unimer until the mole fraction of surfactant approaches X, and abruptly thereafter almost all additional surfactant will aggregate into micelles of size o or so (see Fig. 12-3). The concentration at which most additional surfactant forms large aggregates is called the critical micelle concentration, or CMC, and its value is close to X. The detailed distribution of micelle sizes is controlled by the dependence of on n. 

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