scholarly journals Inventory model for deteriorating items with negative exponential demand, probabilistic deterioration and fuzzy lead time under partial back logging

2020 ◽  
Vol 30 (3) ◽  
Author(s):  
Nabendu Sen ◽  
Sumit Saha
Keyword(s):  
Inventory Management ◽  
Lead Time ◽  
Probability Distributions ◽  
Optimal Strategies ◽  
Inventory Model ◽  
Deteriorating Items ◽  
Optimal Time ◽  
Inventory Cost ◽  
Total Inventory ◽  
Negative Exponential

The effect of lead time plays an important role in inventory management. It is also important to study the optimal strategies when the lead time is not precisely known to the decision makers. The aim of this paper is to examine the inventory model for deteriorating items with fuzzy lead time, negative exponential demand, and partially backlogged shortages. This model is unique in its nature due to probabilistic deterioration along with fuzzy lead time. The fuzzy lead time is assumed to be triangular, parabolic, trapezoidal numbers and the graded mean integration representation method is used for the defuzzification purpose. Moreover, three different types of probability distributions, namely uniform, triangular and Beta are used for rate of deterioration to find optimal time and associated total inventory cost. The developed model is validated numerically and values of optimal time and total inventory cost are given in tabular form, corresponding to different probability distribution and fuzzy lead-time. The sensitivity analysis is performed on variation of key parameters to observe its effect on the developed model. Graphical representations are also given in support of derived optimal inventory cost vs. time.

scholarly journals Controllable deterioration rate for time-dependent demand and time-varying holding cost

2014 ◽  
Vol 24 (1) ◽  
pp. 87-98 ◽  
Author(s):  
Vinod Mishra
Keyword(s):  
Linear Function ◽  
Inventory Model ◽  
Deteriorating Items ◽  
Inventory Cost ◽  
Deterioration Rate ◽  
Preservation Technology ◽  
Demand Rate ◽  
Holding Cost ◽  
Total Inventory ◽  
Dependent Demand

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.

scholarly journals Pengembangan Model Vendor Managed Inventory dengan Banyak Retailer yang Mempertimbangkan Ketidakpastian Lead Times

2018 ◽  
Vol 7 (1) ◽  
pp. 41
Author(s):  
Carles Sitompul ◽  
Paulina Ariningsih ◽  
Ida Bagus Deva Narswara Santosa
Keyword(s):  
Inventory Management ◽  
Lead Time ◽  
Mathematical Formulation ◽  
Lead Times ◽  
Approximation Model ◽  
Vendor Managed Inventory ◽  
Inventory Cost ◽  
Inventory Management System ◽  
Total Inventory ◽  
The Cost

<p><em>An inventory management system in supply chains called Vendor Managed Inventory (VMI) is very promising due to the cost efficiency resulted from implementing such system. This research aims to develop a vendor managed inventory for multiple retailers. The model also takes into account lead time uncertainties from vendor to its retailers. A mathematical formulation for VMI with multiple retailers is first developed using deterministic lead times.  Subsequently, lead times uncertainties are then taken into account where modes lead times are broken into two components: modes and delays, each with their respective probabilities. In turn, an approximation model is used to solve the problem because the complexity aroused from the model is difficult to solve using analytical methods. It is shown that the proposed approximation method is able to solve VMI problem with multiple retailers and uncertain lead times.  Furthermore, the total inventory cost is significantly reduced when compared to the usual economic order quantity method because stockouts are less frequent. </em></p>

scholarly journals Inventory simulation-optimization model for small business

2020 ◽  
Vol 1 (2) ◽  
pp. 55-60
Author(s):  
Yudhia Mulya
Keyword(s):  
Inventory Management ◽  
Lead Time ◽  
Simulation Optimization ◽  
Minimum Cost ◽  
Uncertain Demand ◽  
Optimal Order ◽  
Inventory Cost ◽  
Business Decision ◽  
Total Inventory ◽  
Cost Simulation

Simulation-optimization inventory models are widely used in inventory management studies, including for perishable good. A good inventory management is required to save inventory cost. We use simulation approach to take into consideration of uncertain demand and lead time to obtain a better result of optimal order quantity that minimizes inventory cost. Simulation result shows that simulation-optimization models generates lower total inventory cost. The simulation provides information of objectives in inventory management: (1) how much to order and (2) when to order with minimum cost which gives valuable information in business decision making.

scholarly journals An Inventory Model for Deteriorating Drugs with Stochastic Lead Time

2018 ◽  
Vol 15 (12) ◽  
pp. 2772 ◽  
Author(s):  
Jian Li ◽  
Lu Liu ◽  
Hao Hu ◽  
Qiuhong Zhao ◽  
Libin Guo
Keyword(s):  
Shelf Life ◽  
Inventory Management ◽  
Lead Time ◽  
Service Level ◽  
Inventory Model ◽  
Effective Management ◽  
Product Availability ◽  
Stochastic Lead Time ◽  
Random Lead Time ◽  
The Right

Inventory management of deteriorating drugs has attracted considerable attention recently in hospitals. Drugs are a kind of special product. Two characteristics of some drugs are the shorter shelf life and high service level. This causes hospitals a great deal of difficulty in inventory management of perishable drugs. On one hand, hospitals should increase the drug inventory to achieve a higher service level. On the other hand, hospitals should decrease the drug inventory because of the short shelf life of drugs. An effective management of pharmaceuticals is required to ensure 100% product availability at the right time, at the right cost, in good conditions to the right customers. This requires a trade-off between shelf-life and service level. In addition, many uncontrollable factors can lead to random lead time of drugs. This paper focuses on deteriorating drugs with stochastic lead time. We have established a stochastic lead time inventory model for deteriorating drugs with fixed demand. The lead time obeyed a certain distribution function and shortages were allowed. This model also considered constraints on service level, stock space and drug shelf life. Through the analysis of the model, the shelf life of drugs and service level were weighted in different lead time distributions. Empirical analysis and sensitivity analysis were given to get reach important conclusions and enlightenment.

scholarly journals Vendor-Buyers relationship model for deteriorating items with shortages, fuzzy trapezoidal costs and inflation

2013 ◽  
Vol 23 (1) ◽  
pp. 73-85 ◽  
Author(s):  
Chaman Singh ◽  
S.R. Singh
Keyword(s):  
Optimal Policy ◽  
Fuzzy Numbers ◽  
Deteriorating Items ◽  
Inventory Cost ◽  
Fuzzy Environment ◽  
Relationship Model ◽  
Present Worth ◽  
Total Inventory ◽  
Integrated Cost ◽  
Representation Method

In this paper, an integrated inventory model is developed from the perspective of a single vendor and multi-buyers for deteriorating items under fuzzy environment and inflation. In the development of the model, it is assumed that all costs parameters, demand and the production rates are imprecise in nature; they are represented by the trapezoidal fuzzy numbers, as these parameters are not constant and can be disturbed due to daily market changes. We use function principle as arithmetic operations to find the total inventory cost in fuzzy sense and Graded Mean - Integration Representation Method to defuzzify the fuzzy total inventory cost. Inflation is used to find the present worth of total cost. Since the optimal policy of buyers may not be the most economical for a vendor, thus to deal with this situation, integrated cost policy is used to reach the optimal policy. Finally, a numerical example is given to illustrate the model.

scholarly journals Inventory Model with Partial Backordering When Backordered Customers Delay Purchase after Stockout-Restoration

2016 ◽  
Vol 2016 ◽  
pp. 1-16
Author(s):  
Ren-Qian Zhang ◽  
Yan-Liang Wu ◽  
Wei-Guo Fang ◽  
Wen-Hui Zhou
Keyword(s):  
Layer Structure ◽  
Inventory Model ◽  
Inventory Cost ◽  
Cost Component ◽  
Lipschitz Optimization ◽  
Partial Backordering ◽  
Demand Rate ◽  
Holding Cost ◽  
Total Inventory ◽  
Inventory Holding

Many inventory models with partial backordering assume that the backordered demand must be filled instantly after stockout restoration. In practice, however, the backordered customers may successively revisit the store because of the purchase delay behavior, producing a limited backorder demand rate and resulting in an extra inventory holding cost. Hence, in this paper we formulate the inventory model with partial backordering considering the purchase delay of the backordered customers and assuming that the backorder demand rate is proportional to the remaining backordered demand. Particularly, we model the problem by introducing a new inventory cost component of holding the backordered items, which has not been considered in the existing models. We propose an algorithm with a two-layer structure based on Lipschitz Optimization (LO) to minimize the total inventory cost. Numerical experiments show that the proposed algorithm outperforms two benchmarks in both optimality and efficiency. We also observe that the earlier the backordered customer revisits the store, the smaller the inventory cost and the fill rate are, but the longer the order cycle is. In addition, if the backordered customers revisit the store without too much delay, the basic EOQ with partial backordering approximates our model very well.

scholarly journals Two warehouse inventory model for deteriorating item with exponential demand rate and permissible delay in payment

2017 ◽  
Vol 27 (1) ◽  
pp. 109-124 ◽  
Author(s):  
Naresh Kaliraman ◽  
Ritu Raj ◽  
Shalini Chandra ◽  
Harish Chaudhary
Keyword(s):  
Sensitivity Analysis ◽  
Inventory Model ◽  
Deteriorating Items ◽  
The Other ◽  
Inventory Cost ◽  
Numerical Illustration ◽  
Deterioration Rate ◽  
Permissible Delay In Payment ◽  
Demand Rate

A two warehouse inventory model for deteriorating items is considered with exponential demand rate and permissible delay in payment. Shortage is not allowed and deterioration rate is constant. In the model, one warehouse is rented and the other is owned. The rented warehouse is provided with better facility for the stock than the owned warehouse, but is charged more. The objective of this model is to find the best replenishment policies for minimizing the total appropriate inventory cost. A numerical illustration and sensitivity analysis is provided.

scholarly journals Manajemen Persediaan Tepung Terigu dengan Metode Economic Order Quantity (EOQ) pada Perusahaan Roti Nikki Echo Payakumbuh

2018 ◽  
Vol 1 (1) ◽  
pp. 21-27
Author(s):  
Desi Rahma Yani ◽  
Mega Amelia Putri ◽  
John Nefri
Keyword(s):  
Inventory Management ◽  
Production Cost ◽  
Raw Material ◽  
Economic Order Quantity ◽  
Economic Order ◽  
Order Quantity ◽  
Inventory Cost ◽  
Company Policy ◽  
Total Inventory ◽  
A Company

Inventory management has an important role in a company because inventory management can decrease production cost. Economic order quantity using to minimize the production cost. Inventory management of flour in bread company Nikki Echo not been seen clearly prove by  so many booking amount. It can giving addition of cost. The purpose of this research is (1) Analyzing optimal flour stock by using EOQ method in bread company Nikki Echo, (2) Analyzing reorder point raw material inventory by using EOQ method in bread company Nikki Echo, (3) Analyzing total raw material inventory cost by using EOQ method in bread company Nikki Echo. This research be held from February 20 until April 19 2018 in bread company Nikki Echo, Tanjung Pauh, Payakumbuh city, West Sumatera province. Flour stock by using EOQ method as much 17.394 kg it means the amount greater than company policy. That amount increase 79,6% from the amount set by company. Frequency of booking less than company policy that is 7 times booking. Amount of reorder by using EOQ method is 10.251 kg with the inventory lead time for 3 days. Total inventory cost by using EOQ method as many Rp 11.445.513. This value small than total inventory cost issued by company policy. Decreasing cost amount 98% from company policy. That cause by ordering amount reduced 33 times or same with 82,5% from the amount before

scholarly journals Multi-Objective Inventory Model with Lead-Time and Defective Items

2019 ◽  
Vol 9 (2) ◽  
pp. 2415-2420
Keyword(s):  
Lead Time ◽  
Inventory Model ◽  
Inventory Problem ◽  
Defective Items ◽  
Multi Objective ◽  
Deterministic Demand ◽  
Decision Making Problem ◽  
Holding Cost ◽  
Total Inventory

Inventory problem are generally classified under decision making problem where lead time plays an important role in performance and services to customers during supply and placement of order of an item orders can be placed in shorter lead time with higher price or in longer lead time with lower cost. In this paper we have formulated multi-objective inventory model with one objective of minimizing the total inventory cost and other objective of maintaining the quality of the product by discarding the defective items. The model involved the deterministic demand, lead time dependent lead time cost, holding cost, ordering cost and inspection cost for inspecting defective items. The techniques of priority goal programming and genetic algorithm are applied and the results are compared. The sensitivity analysis is explained due to restriction in cost parameter. The model is finally illustrated with a numerical example.

scholarly journals Decreasing Total Inventory Cost by Controlling Inventory in Motorcycle Dealer

2020 ◽  
Vol 22 (2) ◽  
pp. 41-49
Author(s):  
David ◽  
Engmir ◽  
Irwan Budiman ◽  
Jusra Tampubolon
Keyword(s):  
Inventory Management ◽  
Demand Forecasting ◽  
Spare Parts ◽  
Order Quantity ◽  
Inventory Cost ◽  
Safety Stock ◽  
Safety Stocks ◽  
Forecasting Method ◽  
Total Inventory ◽  
Abc Analysis

This research was conducted at one of the motorcycle dealers in Indonesia. Besides selling motorcycles, this dealer also provides services to repair motorcycles and sells genuine motorcycle parts. Inventory management which the company carried out is still not good enough because there are still demand for spare parts from consumers that cannot be fulfilled by the company. The purpose of this study is to draw up a plan to control spare parts by paying attention to the spare parts that need to be considered, estimating the exact number of spare parts demand, knowing the smallest total inventory cost, knowing the amount of safety stock needed, and knowing when to reorder. In preparing the spare parts control, the methods used are ABC analysis, demand forecasting method, and EOQ method. The results of this study are plans to control the inventory of Tire, Rr. such as the forecasting sales of Tire, Rr. as many as 17338, economic order quantity of Tire Rr are 2158 units, the number of safety stocks of Tire, Rr. needed in 2020 are 1738 units, and the reorder point in 2020 is 8 times with the total inventory cost for Tire, Rr. in 2020 is Rp. 30,009,005.

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