scholarly journals Dynamic Demand and Pricing Inventory Model for Non-Instantaneous Deteriorating Items

Author(s):  
Nita H. Shah ◽  
Kavita Rabari ◽  
Ekta Patel

In this model, an inventory model for deteriorating products with dynamic demand is developed under time-dependent selling price. The selling price is supposed to be a time-dependent function of initial price of the products and the permissible discount rate at the time of deterioration. The object is sold with the constant rate in the absence of deterioration and is the exponential function of discount rate at the time; deterioration takes place. Here, the demand not only dependent on the selling price but also on the cumulative demand that represents the saturation and diffusion effect. First, an inventory model is formulated to characterize the profit function. The Classical optimization algorithm is used to solve the optimization problem. The objective is to maximize the total profit of the retailers with respect to the initial selling price and cycle time. Concavity of the objective function is discussed through graphs. At last, a sensitivity analysis is performed by changing inventory parameters and their impact on the decision variables i.e. (initial price, cycle time) together with the profit function.

Author(s):  
Monika Naik ◽  
Nita H. Shah

This article includes policies regarding optimal dynamic pricing and ordering for items with synchronized deterioration of quality and physical quantity. Qualitative deterioration is an instantaneous process while physical deterioration-a non-instantaneous process. In view of the dynamic nature of the problem, selling price is assumed to be a time-dependent function of the initial price and discount rate. Initially with no physical deterioration, the product is sold at initial price value in the time period, successively in order to enhance customer's demand, price is exponentially discounted. For boosting the dynamic essence of the proposed model, the customer's demand is expressed as a quadratic function of time, price and changes in price over time, which is appropriate for the products for which demand increases initially and after sometime, it starts to decrease. Along with determining initial price, discount rate and optimal ordering cycle, the model also maximizes the total profit of the system. Numerical results with sensitivity analysis on the decision variables outputs managerial insights.


Author(s):  
Nita Shah ◽  
Ekta Patel ◽  
Kavita Rabari

Aims: This article analyzes an inventory system for deteriorating items. The demand is quadratic function of time and is dependent on time, price and advertisement. Shortages are allowed and partially backlogged. Background: Demand and pricing are the two most crucial factors in inventory policy for any business to be successful. In today’s era of competitive circumstances, any product is promoted through advertisement, which plays a vital role in changing the demand pattern among the community. The marketing and demonstration of an item by time-to-time with fashionable advertisements through well-known media such as TV, radio, newspaper, magazine, etc. However, this idea is not always true for some goods like wheat, vegetables, fruits, food grains, medicines and other perishable goods due to their deteriorating nature and this in turn decreases demand for such goods. Deterioration may define as decay, damage, spoilage, evaporation, obsolescence, pilferage. Hence, deterioration effect is a major part in inventory control theory. So in this article demand rate is considered to be a function of selling price, time and occurrence of advertisement instantaneously. Objective: A solution procedure is obtained to find optimal number of price changes and optimal selling price to maximize the total profit. Method: Classical Optimization. Result: From the sensitivity analysis table, it can be seen that the optimal profit is highly sensible to advertisement coefficient and purchase cost. With an increment in rate of deterioration, selling price decreases. Scale demand has reasonable effect on cycle time and selling price. When the value of increase, the cycle length and profit goes on decreasing. Growth in profit is observed if we increase parameter b, higher will be the profit. Price elasticity is sensible parameter with respect to selling price. If backlogging rate increases, the profit will decreases. The inventory parameters holding cost, back order cost and lost sale cost have marginal effect on total profit. Conclusion: In this article, an inventory model is proposed for deteriorating items with variable demand depends upon the advertisement, selling price of the item and time. Shortages are allowed and partially backlogged and backlogging rate depends on the waiting time for the next replenishment. From this article, we can conclude that the parameters are insensible with respect to optimal profit, cycle time and selling price and rest of the parameters have practical output on total profit.


Author(s):  
Nita H. Shah ◽  
Monika K. Naik

It was usually observed in typical EOQ inventory models that the holding cost, the purchasing cost and the demand rate are constant and the purchasing cost is irrespective of the order size. But practically, the demand rate is based on various factors including sale price, seasonality and availability. Due to the lengthening of shortage periods, the holding cost per unit item increases. Also with the inclusion of quantity discounts, the unit purchasing cost is usually decreased for higher order sizes. This article addresses jointly with the inconsistency of the rate of demand, unit purchasing cost and unit holding cost for deteriorating items. This paper proposes a model based on an inventory problem including selling price of products and stock-dependent market demand rate, holding cost based on storage time and purchasing cost is influenced by order size by offering all units quantity discounts. An algorithm for estimating the optimum solution of decision variables by maximizing total profit and minimizing the overall cost of the model is developed in this paper. Validation of the developed model is confirmed with the help of a numerical example along with the sensitivity-analysis of decision variables by varying various inventory parameters.


2012 ◽  
Vol 1 (2) ◽  
pp. 53-79
Author(s):  
Chandra K. Jaggi ◽  
Sarla Pareek ◽  
Anuj Sharma ◽  
Nidhi

In this paper, a fuzzy inventory model is formulated for deteriorating items with price dependent demand under the consideration of permissible delay in payment. A two parameter Weibull distribution is taken to represent the time to deterioration. Shortages are allowed and completely backlogged. For Fuzzification of the model, the demand rate, holding cost, unit purchase cost, deterioration rate, ordering cost, shortage cost, interest earn and interest paid are assumed to be triangular fuzzy numbers. As a result, the profit function will be derived in fuzzy sense in order to obtain the optimal stock-in period, cycle length and the selling price. The graded mean integration method is used to defuzzify the profit function. Then, to test the validity of the model a numerical example is considered and solved. Finally, to study the effect of changes of different parameters on the optimal solution i.e. average profit, order quantity, stock-in period, cycle length and selling price, sensitivity analysis are performed.


Mathematics ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1157
Author(s):  
Valentín Pando ◽  
Luis A. San-José ◽  
Joaquín Sicilia ◽  
David Alcaide-López-de-Pablo

This paper presents the optimal policy for an inventory model where the demand rate potentially depends on both selling price and stock level. The goal is the maximization of the profitability index, defined as the ratio income/expense. A numerical algorithm is proposed to calculate the optimal selling price. The optimal values for the depletion time, the cycle time, the maximum profitability index, and the lot size are evaluated from the selling price. The solution shows that the inventory must be replenished when the stock is depleted, i.e., the depletion time is always equal to the cycle time. The optimal policy is obtained with a suitable balance between ordering cost and holding cost. A condition that ensures the profitability of the financial investment in the inventory is established from the initial parameters. Profitability thresholds for several parameters, including the scale and the non-centrality parameters, keeping all the others fixed, are evaluated. The model with an isoelastic price-dependent demand is solved as a particular case. In this last model, all the optimal values are given in a closed form, and a sensitivity analysis is performed for several parameters, including the scale parameter. The results are illustrated with numerical examples.


2021 ◽  
Vol 23 (04) ◽  
pp. 225-237
Author(s):  
G.S. Buttar ◽  
◽  
Ruchi Sharma Sharma ◽  

In this paper, an inventory model for production of a single article with an uneven manufacturing rate and manufacturing time subsidiary selling cost has been considered. The considered production inventory model is accepted to create perfect items in beginning however because of different elements, after some time the production begins diminishing exponentially with time, i.e., the variable production rate has been thought of. The demand is time subordinate. Initially up to certain time, production rate remains constant. But after some time, due to various factors, production will decrease. Therefore, the efficiency (E) of such factors must be increased to get more production which can maintain the production efficiency cost which has been applied. Considering this fact inverse efficiency λ has been introduced in production rate. By utilizing differential calculus, expected maximum profit has been resolved. The goal of the examination is to decide the ideal arrangement for a production framework that expands the total benefit subject to certain limitations viable. Results are examined by means of a mathematical example to outline the hypothesis.


2021 ◽  
Vol 33 (4) ◽  
pp. 51-65
Author(s):  
SUSHIL KUMAR ◽  

Production inventory models have an important role in production planning and scheduling. In any economic production quantity (EPQ) model, the production rate is dependent on demand. In this paper we have established a production inventory model for perishable items with partial backlogging and time dependent exponential demand rate. Allowing shortage, it is partially backlogged. The unsatisfied demand is backlogged and it is considered a function of waiting time. The aim of our study is to optimizing the total profit during a given cycle. A numerical example is given in showing the applicability of the developed model.


Author(s):  
Dushyantkumar G. Patel ◽  
Nita H. Shah ◽  
Digeshkumar B. Shah

To boost the sale is the prime objective for promoters. For this purpose, they generally allow credit period. In this article, we have considered an inventory model in which supplier gives credit period to retailer and to increase the sale, retailer passes it to end customers. This phenomenon is known as two level trade credits. By allowing credit period we may encounter with the issue of default risk which has been taken care of while calculating profit function for the system. Also, each and every inventory product gets deteriorated over the time as per its nature and such deteriorating products have its maximum life time as well. The present inventory model deals with such products. Quadratic demand is discussed here which is suitable for the products for which demand increases initially and after sometimes it shows decreasing pattern. Finally, retailer's total profit is maximized with respect to credit period and cycle time. Numerical examples are given to validate the model. Sensitivity analyses are done to filter significant inventory parameters.


2020 ◽  
Vol 11 (3) ◽  
pp. 928
Author(s):  
Satya Kumar Das ◽  
Sahidul Islam

In this paper, we have formulated an inventory model with time dependent holding cost, selling price as well as time dependent demand. Multi-item inventory model has been considered under limitation on storage space. Due to uncertainty all the require cost parameters are taken as generalized trapezoidal fuzzy number. Our proposed multi-objective inventory model has been solved by using fuzzy programming techniques which are FNLP, FAGP, WFNLP and WFAGP methods. A numerical example is provided to demonstrate the application of the model. Finally to illustrate the model and sensitivity analysis and graphical representation have been shown. 


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