258 research outputs found
A PERISHABLE INVENTORY MODEL WITH UNKNOWN TIME HORIZON
Traditionally, the time (planning) horizon over which
the inventory for a particular item will be controlled is often assumed to be known (finite or infinite) and the total inventory cost is usually obtained by summing up the cost over the entire time horizon. However, in some inventory situations the period over which the inventory will be controlled are difficult to predict with certainty, as the inventory problems may not live up to or live beyond the assumed planning horizon, thereby affecting the optimality of the model. This paper presents a deterministic perishable inventory model for items with linear trend in demand and constant deterioration when time horizon is unknown, unspecified or unbounded. The heuristic model obtains replenishment policy by determining the ordering schedule to minimize the total cost per unit time over the duration of each schedule. A numerical example and sensitivity analysis are given to illustrate the model
Controllable deterioration rate for time-dependent demand and time-varying holding cost
In this paper, we develop an inventory model for non-instantaneous
deteriorating items under the consideration of the facts: deterioration rate
can be controlled by using the preservation technology (PT) during
deteriorating period, and holding cost and demand rate both are linear
function of time, which was treated as constant in most of the deteriorating
inventory models. So in this paper, we developed a deterministic inventory
model for non-instantaneous deteriorating items in which both demand rate and
holding cost are a linear function of time, deterioration rate is constant,
backlogging rate is variable and depend on the length of the next
replenishment, shortages are allowed and partially backlogged. The model is
solved analytically by minimizing the total cost of the inventory system. The
model can be applied to optimizing the total inventory cost of
non-instantaneous deteriorating items inventory for the business enterprises,
where the preservation technology is used to control the deterioration rate,
and demand & holding cost both are a linear function of time
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
An inventory model of instantaneous deteriorating items with controllable deterioration rate for time dependent demand and holding cost
Purpose: The purpose of this paper to develop an inventory model for instantaneous deteriorating items with the consideration of the facts that the deterioration rate can be controlled by using the preservation technology (PT) and the holding cost & demand rate both are linear function of time which was treated as constant in most of the deteriorating inventory model.
Design/methodology/approach: Developed the mathematical equation of deterministic deteriorating inventory model in which demand rate and holding cost both is linear function of time, deterioration rate is constant, backlogging rate is variable and depend on the length of the next replenishment, shortages are allowed and partially backlogged and obtain an analytical solution which optimizes the total cost of the proposed inventory model.
Findings: The model can be applied for optimizing the total inventory cost of deteriorating items inventory for such business enterprises where they use the preservation technology to control the deterioration rate under other assumptions of the model.
Originality/value: The inventory system for deteriorating items has been an object of study for a long time, but little is known about the effect of investing in reducing the rate of product deterioration and their significant impact in the business. The proposed model is effective as well as efficient for the business organization that uses the preservation technology to reduce the deterioration rate of the instantaneous deteriorating items of the inventory.Peer Reviewe
An Inventory Model for Deteriorating Commodity under Stock Dependent Selling Rate
Economic order quantity (EOQ) is one of the most important inventory policy that have to be decided
in managing an inventory system. The problem addressed in this paper concerns with the decision of the optimal
replenishment time for ordering an EOQ to a supplier. This Model is captured the affect of stock dependent
selling rate and varying price. We developed an inventory model under varying of demand-deterioration-price of
commodity when the relationship of supplier-grocery-consumer at stochastic environment. The replenishment
assumed instantaneous with zero lead time. The commodity will decay of quality according to the original
condition with randomize characteristics. First, the model is addressed to solve a problem phenomenon how long
is the optimum length of cycle time. Then, an EOQ of commodity to be ordered by will be determined by model.
To solve this problem, the first step is developed a mathematical model based on reference’s model, and then
solve the model analytically. Finally, an inventory model for deteriorating commodity under stock dependent
selling rate and considering selling price was derived by this research.
Keywords: deterioration commodity, expected profit, optimal replenishment time stock dependent selling rate
A Two Warehouse Inventory Model with Stock-Dependent Demand and variable deterioration rate
In this paper we discuss a two warehouses inventory model for non-instantaneous deteriorating items. Throughout last so many years, mostly researchers have consideration to the situation where the demand rate is dependent on the level of the on-hand inventory. For inventory systems, such as fashionable commodities, the length of the waiting time for the next replenishment would determine whether the backlogging will be accepted or not. In real life situation, enterprises usually buy more goods than can be stored in their own warehouses (OW) for future production or sales. The surplus quantities are frequently stored in an extra storage space, represented by rented warehouses (RW).The rented warehouse is considered to charge high unit holding cost than the own warehouse. The necessary and sufficient conditions of the existence and uniqueness of the optimal solution are shown. We determine the optimal replenishment policy for non-instantaneous deteriorating items with partial backlogging and stock-dependent demand
A study of inflation effects on an EOQ model for Weibull deteriorating/ameliorating items with ramp type of demand and shortages
This paper deals with the effects of inflation and time discounting on an inventory model with general ramp type demand rate, time dependent (Weibull) deterioration rate and partial backlogging of unsatisfied demand. The model is studied under the replenishment policy, starting with shortages under two different types of backlogging rates, and their comparative study is also provided. We then use the computer software, MATLto find the optimal replenishment policies. Duration of positive inventory level is taken as the decision variable to minimize the total cost of the proposed system. Numerical examples are then taken to illustrate the solution procedure. Finally, sensitivity of the optimal solution to changes of the values of different system parameters is also studied
An optimization of an inventory model of decaying-lot depleted by declining market demand and extended with discretely variable holding costs
Inventory management is considered as major concerns of every organization. In inventory holding, many steps are taken by managers that result a cost involved in this row. This cost may not be constant in nature during time horizon in which perishable stock is held. To investigate on such a case, this study proposes an optimization of inventory model where items deteriorate in stock conditions. To generalize the decaying conditions based on location of warehouse and conditions of storing, the rate of deterioration follows the Weibull distribution function. The demand of fresh item is declining with time exponentially (because no item can always sustain top place in the list of consumers’ choice practically e.g. FMCG). Shortages are allowed and backlogged, partially. Conditions for global optimality and uniqueness of the solutions are derived, separately. The results of some numerical instances are analyzed under various conditions
Optimal Pricing Policies For Deteriorating items With Preservation Technology And Price Sensitive Demand
This paper considers the problem of determining the price, cycle time and preservation technology cost strategies for deteriorating items. It is assumed that preservation technology investment and demand rate do follow the function of selling price. The objective is to maximize the total profit per unit time with determining the optimal selling price, length of replenishment cycle and preservation technology investment. We will be proving that the optimal cycle length and selling price are unique with respect to given preservation cost. Also, total profit per unit time will be a concave function as it will reach its optimum value for optimum value of selling price, cycle length and preservation technology cost. Numerical examples are also presented to demonstrate the solution process
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