Two Warehouse Inventory Model for Deteriorating Products with Stock Dependent Demand and Shortages

In this paper a deterministic inventory model for two warehouses has been developed. In two warehouses the first is the owned warehouse with a fixed capacity of W units and the other one is rented warehouse with unlimited stocking capacity. The deterioration occurs in both the warehouses. First the demand is fulfilled from the inventory in rented warehouse and after thatthe inventory in owned warehouse has been used. The shortages are allowed in owned warehouse only and the excess demand is partially backlogged. For the generality of the model we presented the equations for total cost of the system. A numerical example and sensitivity analysis with respect to different associated parameters has also been presented to illustrate the model

An Inventory Model for Weibull Distributed Deteriorating Items Under Ramp Type Demand and Permissible Trade Credit Policy

In a classical inventory economic order quantity (EOQ) model, the stock is depleted due to both market demand and deterioration. Many inventory models are developed for items under variable rate of deterioration. The two parameter Weibull distributed term is a representation of constant, time dependent linear and non-linear, increasing and decreasing rate of deterioration. Again the demand rate is assumed here as time dependent in beginning of cycle and then becomes constant as passage of time. Shortages are allowed and fully backlogged. Moreover the trade credit policy is a win-win payment strategy for sharing profit in the inventory system. This present paper deals with a replenishment policy assuming two parameter Weibull distributed deteriorating items, demand rate a ramp type function of time under permissible trade credit policy. Finally several numerical examples are given to illustrate the model and some particular cases are also discussed along with its’ illustrations along with concluding remarks. Keywords: Inventory, Weibull distribution, deterioration, ramp type, trade credit and shortages. Subject classification: AMS Classification No. 90B05 DOI: 10.7176/EJBM/13-19-03 Publication date:October 31st 202

FUZZY INVENTORY MODEL FOR ITEMS WITH WEIBULL DISTRIBUTION DETERIORATION, POWER DEMAND, LINEAR HOLDING COST, SALVAGE COST AND PARTIAL BACKLOGGING

The objective of this research article is to develop an inventory model which incorporates power pattern demand, Weibull distribution deterioration, shortages and partial backlogging of orders. Holding cost is taken as time dependent and deteriorated items are assumed to have a salvage value. The cost parameters are fuzzified and the total cost is defuzzified using Graded mean representation, signed distance and centroid methods. The values obtained by these methods are compared with the help of numerical examples. The convexity of the cost function is depicted graphically. Sensitivity analysis is performed to study the effect of change in some parameters. Keywords: Inventory, Power demand, Partial backlogging, Deterioration, Triangular Fuzzy Number, Defuzzification, Graded mean represented method, Signed Distance Method, centroid method

A production inventory model with deteriorating items and shortages

A continuous production control inventory model for deteriorating items with shortages is developed. A number of structural properties of the inventory system are studied analytically. The formulae for the optimal average system cost, stock level, backlog level and production cycle time are derived when the deterioration rate is very small. Numerical examples are taken to illustrate the procedure of finding the optimal total inventory cost, stock level, backlog level and production cycle time. Sensitivity analysis is carried out to demonstrate the effects of changing parameter values on the optimal solution of the system

An Epq Model Having Weibull Distribution Deterioration With Exponential Demand and Production With Shortages Under Permissible Delay In Payments

In the fundamental production inventory model, in order to solve the economic production quantity (EPQ) we always fix both the demand quantity and the production quantity per day. But, in the real situation, production is usually dependend on demand. This paper derives a production model for the lot-size inventory system with finite production rate, taking into consideration the effect of decay and the condition of permissible delay in payments. Usually no interest is  charged  if the outstanding amount is settled within the permitted fixed settlement period. Therefore, it makes economic sense for the customer to delay the settlement of the replenishment account up to the last moment of the permissible period allowed by the supplier. In this model shortages are permitted and fully backordered . The purpose of this paper is to investigate a computing schema for the EPQ. The model is illustrated with a numerical example. Keywords Economic production quantity, permissible delay, weibull distribution, deterioration

A two-storage model for deteriorating items with holding cost under inflation and Genetic Algorithms

A deterministic inventory model has been developed for deteriorating items and Genetic Algorithms (GA) having a ramp type demands with the effects of inflation with two-storage facilities. The owned warehouse (OW) has a fixed capacity of W units; the rented warehouse (RW) has unlimited capacity. Here, we assumed that the inventory holding cost in RW is higher than those in OW. Shortages in inventory are allowed and partially backlogged and Genetic Algorithms (GA) it is assumed that the inventory deteriorates over time at a variable deterioration rate. The effect of inflation has also been considered for various costs associated with the inventory system and Genetic Algorithms (GA). Numerical example is also used to study the behaviour of the model. Cost minimization technique is used to get the expressions for total cost and other parameters

Inventory policy for a deteriorating item: quadratic demand with shortages

We develop an inventory model for a deteriorating item having an instantaneous supply with a quadratic time-varying demand given by f(t)=a+bt+ct2; a&#88050, b&#88000, c&#88000 with shortages. The model is solved analytically to obtain the optimal solution for the problem. The sensitivity analysis of the optimal solution toward change in the values of the different system parameters is also examined. Numerical example is given to illustrate the proposed model. Journal of Science and Technology (Ghana) Vol. 27 (2) 2007: pp. 89-9

Production lot size models for perishable seasonal products

Seasonal items like fruits, fish, winter cosmetics, fashion apparel, etc. generally exhibits different demand patterns at various times during the season. Production and inventory planning must reflect this property for cost effectiveness and optimization of resources. This paper presents two production-inventory models for perishable seasonal products that minimize total inventory costs. The models obtains optimal production run time and optimal production quantity for cases when the production rate is constant and when it is allowed to vary with demand. The products are assumed to deteriorate at an exponential rate and demand for them follows a three-phase ramp type pattern during the season. Numerical examples and sensitivity analysis are carried out. Production run time and production quantity obtained by the model were found to be independent of cost parameters. The variable production rate strategy was also found to give lower inventory costs and production quantity than the constant production rate strategy

Pricing and inventory control policy for non-instantaneous deteriorating items with time- and price-dependent demand and partial backlogging

Determining the optimal inventory control and selling price for deteriorating items is of great significance. In this paper, a joint pricing and inventory control model for deteriorating items with price- and time-dependent demand rate and time-dependent deteriorating rate with partial backlogging is considered. The objective is to determine the optimal price, the replenishment time, and economic order quantity such that the total profit per unit time is maximized. After modeling the problem, an algorithm is proposed to solve the resulted problem. We also prove that the problem statement is concave function and the optimal solution is indeed global