Among both inventory theorists and practitioners, it is common use to include an opportunity cost rate in the holding cost rate. In that way, the cost of capital can be roughly incorporated in an average cost (AC) inventory model. The traditional way for calculating the opportunity cost rate is to multiply the interest rate (or discount rate) by the marginal cost for producing/ordering an item....

The aim of this research was to measure the relative efficiency of forest management plans in north of Iran. In order to fulfill the research, data of 12 forest management plans were collected from the financial balance sheets of Shafaroud Forest Company during a ten years period. First of all, basic Data Envelopment Analysis (DEA) models (BCC and CCR) were used to determine the efficiency. The...

A model for comparing the inventory costs of purchasing under the economic order quantity (EOQ) system and the just-intime (JIT) order purchasing system in existing literature concluded that JIT purchasing was virtually always the preferable inventory ordering system especially at high level of annual demand. By expanding the classical EOQ model, this paper shows that it is possible for the EOQ...

A production-inventory model is proposed for a manufacturing process used to produce a single product in batches to meet a deterministic demand. The process is assumed to be in-control at the start of a production run. Then, the process may shift to an out-of-control state at a random point in time, and a fixed portion of items produced is defective. These defective items cannot be repaired or ...

Inventory model under risk that demand is uncertain is recognized. In this paper, the fuzzy demand per day and fuzzy lead time on a cycle in fuzzy inventory control system are assumed to trapezoidal distribution, trapezoidal fuzzy number by decision maker. A fuzzy inventory model under manager’s preference for order quantity is presented first. This model is given by fuzzy total annual inventor...

Optimization of inventory costs is the most important goal in industries. But in many models, the constraints are considered simple and relaxed. Some actual constraints are to consider the combinatorial production and purchase models in multi-products environment. The purpose of this article is to improve the efficiency of inventory management and find the economic order quantity and economic p...

In this paper we present a quantity-based model for integrated inventory replenishment and shipment consolidation decisions under vendor managed inventory. Assuming the vendor uses a special reorder point, order-up-to level, or ( , ) s S policy for inventory control and adopts a quantity-based dispatching strategy under stochastic settings, we build its simulation model. By simulating in Arena ...

Typical models of the production inventory systems assume that lot sizes of raw materials and final products are treated separately which leads to suboptimization production process. In this paper, a unified inventory model of an integrated production inventory system, where each of production, demand and deterioration rates are general functions of time, is considered. Shortage for the final p...