Order Quantity Model For Items Research Articles

An inventory model for deteriorating items with expiry date and time varying holding cost

In this paper, an economic order quantity model for items which deteriorate and expire with time has been developed. The holding cost has been assumed to be a linear function of time, whereas demand has been considered as a function of expiry date and selling price. Shortages are allowed and partially backlogged. The model so developed has been discussed for two cases of partial backlogging: 1) backlogging rate is taken to be constant; 2) backlogging rate depends upon waiting time. A numerical example given here illustrates each case. Finally, sensitivity analysis is carried out to analyse the behaviour of the model.

An inventory model for deteriorating items with expiry date and time varying holding cost

In this paper, an economic order quantity model for items which deteriorate and expire with time has been developed. The holding cost has been assumed to be a linear function of time, whereas demand has been considered as a function of expiry date and selling price. Shortages are allowed and partially backlogged. The model so developed has been discussed for two cases of partial backlogging: 1) backlogging rate is taken to be constant; 2) backlogging rate depends upon waiting time. A numerical example given here illustrates each case. Finally, sensitivity analysis is carried out to analyse the behaviour of the model.

Economic order quantity models for items with imperfect quality and emission considerations

ABSTRACTIncorporation of quality and environmental concerns in production and inventory models has received considerable attention in the inventory management literature; however, researchers studied these topics mostly independently. Thus, it is required to jointly incorporate those two relevant aspects in a single research to support decisions, compare the results and obtain new insights for complexities in practice. This paper takes a step in this line of thought and revisits some economic order quantity (EOQ) models with imperfect quality from a sustainable point of view. The objective is to investigate the impact of emission costs on the replenishment order sizes and the total profit of a buyer (retailer) in an imperfect supply process, where the buyer receives the batches containing a percentage of imperfect quality items. First, an EOQ model with imperfect quality items and emission costs, which are the result of warehousing and waste disposal activities, is formulated. Next, the model is extended to account for the situations where the buyer considers different areas for stocking the imperfect and good quality items, learning occurs in imperfect quality and the inspection process at the buyer's end contains error. The developed models are tested numerically and compared to investigate the optimal policies considering emission costs.

A note on: An economic order quantity model for items with imperfect quality and inspection errors

A manufacturing plant treats defectives and non-defectives differently (Wahab and Jaber, 2010). On the basis of this approach, in this technical note, an optimal batch size is determined for the model in Khan et al. (2011a). Furthermore, the model is extended for learning in supplier's quality. These practical extensions of the above model are more in line with the practice in the present-day industry. The numerical results are compared to those in Khan et al. (2011a), and Maddah and Jaber (2008). The proposed model suggests a smaller batch size and lower annual cost than that in Khan et al. (2011a).

Impacts of inspection errors and trade credits on the economic order quantity model for items with imperfect quality

It is common for a retailer to receive some imperfect quality items in a lot. An imperfect inspection process may lead to misclassification errors. Inspection errors due to human fallibility, flawed inspection techniques, or environmental factors can occur, incurring additional costs. In addition, a supplier may provide a permissible delay in payments to stimulate demand from the retailer. In this paper, we develop an economic order quantity (EOQ) model that takes into account these phenomena (i.e., permissible delays in payments, defective items, and inspection errors) in determining the optimal ordering policy that maximises a retailer's total profit. Four theorems are provided to find the retailer's optimal ordering policy. Finally, numerical examples are given to illustrate each of these theorems and sensitivity analysis is performed to obtain managerial insights.

A fuzzy economic order quantity model for items with imperfect quality and partial backordered shortage under screening errors

Traditional view insists that uncertainty is undesirable and should be avoided by all possible means, but according to the modern view, uncertainty is essential to science. It is not an inevitable plague, but it has great utility. Thus, in this paper, a fuzzy economic order quantity (EOQ) model for items with imperfect quality and partial backordered shortage under screening error is developed. In order to present a more realistic and practical model, all the input parameters are assumed to be trapezoidal fuzzy numbers. After formulating the model, the graded mean integration method is used to drive the profit function in fuzzy sense. Then, the optimal policy is determined and finally, numerical examples and sensitivity analysis are carried out to illustrate the sensitiveness of different input parameters.

An economic order quantity model for items experiencing failure in storage

In this paper, an economic order quantity model for items which experience failure according to a probabilistic rate during the storage period is developed. Prior research on item failure has primarily focused on items which can be repaired or sold at a discount. Scenarios that assume repair and discounted sales, however, are impractical for systems where repair costs exceed or are equivalent to item costs and imperfect items are unacceptable. Such cases are prevalent in the medical and electronics industries where defective items are largely unusable. The model presented in this paper is applicable to systems with large fixed order costs and lengthy inventory holding periods. The paper first develops an economic order quantity model for the presented framework. Illustrative numerical examples which demonstrate the effects of certain model parameter changes on optimal order quantity and firm profitability are then provided.

An Economic order quantity model for Items with Three-parameter Weibull distribution Deterioration, Ramp-type Demand and Shortages

In this paper, we develop an economic order quantity inventory model for items with three-parameter Weibull distribution deterioration and ramp-type demand. Shortages are allowed in the inventory system and are completely backlogged. The demand rate is deterministic and varies with time up to a certain point and eventually stabilized and becomes constant. The instantaneous rate of deterioration is an increasing function of time. We provide simple analytical tractable procedures for deriving the model and give numerical examples to illustrate the solution procedure. Our adoption of ramp-type demand reflects a real market demand for newly launched product.

Economic order quantity model for items with imperfect quality with learning in inspection

The economic order quantity (EOQ) model is the simplest and earliest inventory model in the literature. Its simple mathematics is attributed to its assumptions, which are rarely met. Salameh and Jaber [2000. Economic production quantity model for items with imperfect quality. Int. J. Prod. Econ. 64, 59–64] addressed one of these assumptions that items received or produced are not of perfect quality. This paper extends Salameh and Jaber's work for the case where there is learning in inspection. The model is realistic in that it considers situations of lost sales and backorders. Mathematical models are developed with numerical examples provided and results discussed for the cases of (i) partial transfer of learning, (ii) total transfer of learning, and (iii) no transfer of learning.

Economic order quantity model for items with imperfect quality, different holding costs, and learning effects: A note

In this note, we present the optimal lot sizes for an item with imperfect quality based on Salameh and Jaber [Salameh, M. K., & Jaber, M. Y. (2000). Economic production quantity model for items with imperfect quality. International Journal of Production Economics, 64, 59–64], Maddah and Jaber [Maddah, B., & Jaber, M. Y. (2008). Economic order quantity for items with imperfect quality: Revisited. International Journal of Production Economics, 112, 808–815], and Jaber et al. [Jaber, M. Y., Goyal, S. K., & Imran, M. (2008). Economic production quantity for items with imperfect quality subjected to learning effects. International Journal of Production Economics, 115, 143–150] when different holding costs for the good and defective items are considered. When there is no learning effects, the results show that the lot size with different holding costs for good and defective items increases when the percentage of defective increases, as one would expect in the real manufacturing environment. When there is learning effects, the lot size with different holding costs for the good and defective items is more than the one with same holding costs for the good and defective items. However, as the learning takes place in the system, the difference between the lot sizes with and without different holding costs for the good and defective items disappears.

An EOQ model for deteriorating inventory with alternating demand rates

The present paper deals with an economic order quantity model for items deteriorating at some constant rate with demand changing at a known and at a random point of time in the fixed production cycle.

A Comment on An Economic Order Quantity Model for Items with Two Levels of Storage for a Linear Trend in Demand

A Comment on An Economic Order Quantity Model for Items with Two Levels of Storage for a Linear Trend in Demand

A Comment on An Economic Order Quantity Model for Items with Two Levels of Storage for a Linear Trend in Demand

A Comment on An Economic Order Quantity Model for Items with Two Levels of Storage for a Linear Trend in Demand

An Economic Order Quantity Model for Items with Two Levels of Storage for a Linear Trend in Demand

An Economic Order Quantity Model for Items with Two Levels of Storage for a Linear Trend in Demand

An Economic Order Quantity Model for Items with Two Levels of Storage for a Linear Trend in Demand

A deterministic inventory model with two levels of storage (own warehouse and rented warehouse) is studied by considering a linear (positive) trend in demand. Firstly, the model is formulated and solved without allowing backlogging. Secondly, the model is reformulated and solved under the assumptions that shortages in inventory are allowed and backlogged. The results are illustrated with the help of numerical examples.

An Economic Order Quantity Model for Items with Two Levels of Storage for a Linear Trend in Demand

An Economic Order Quantity Model for Items with Two Levels of Storage for a Linear Trend in Demand