Optimization of Inventory for Optimal Replenishment Policies and Lead-Time with Time Varying Demand

2016 ◽  
pp. 201-221
Author(s):  
Kaushik Kumar ◽  
Supriyo Roy
Keyword(s):  
Inventory Management ◽  
Lead Time ◽  
Product Life Cycle ◽  
Inventory Model ◽  
Decision Variable ◽  
Time Varying ◽  
Lot Size ◽  
Solution Approach ◽  
Purchasing Cost ◽  
Increasing Demand

Considering a single period inventory management problem used in the distribution channel to represent consumer demand for marketing/sales of a product, attempt is made to develop a deterministic inventory model with time-varying increasing demand that may be used to reflect sales in different phases of a product life cycle in the competitive market. We propose inventory model assuming replenishment cost is to be linearly dependent on lot size and purchasing cost per unit item is dependent on lead time. Lead time is taken as decision variable. Shortages are allowed to backlog and to lose partly. Our objective is to cumulatively evaluate optimal replenishment lot-size, order time and lead-time for maximization of total profit. Considering the complexities of the proposed model, we propose a heuristic solution approach by developing an ERCM Genetic Algorithm based on ranking section, elitism, whole arithmetic crossover and non-uniform mutation dependent on the age of the population. This heuristics are easy to compute and practical to implement, and perform well in numerical trials.

Analyzing EPQ Inventory Model With Comparison of Exponentially Increasing Demand and Verhult's Demand

2021 ◽  
pp. 227-259
Author(s):  
Kuppulakshmi V. ◽  
Sugapriya C. ◽  
Jeganathan Kathirvel ◽  
Nagarajan Deivanayagampillai
Keyword(s):  
Sensitivity Analysis ◽  
Production Process ◽  
Inventory Management ◽  
Demand Function ◽  
Inventory Model ◽  
Decision Variable ◽  
Working Process ◽  
Management Planning ◽  
Total Cost ◽  
Increasing Demand

This research investigates the comparison of inventory management planning in Verhult's demand and exponentially increasing demand. The working process is different in both the cases coupling the parameters and points out the constraints for the optimal total cost in both the cases. This analysis shows that rate of deterioration and percentage of reworkable items is considered as decision variable in both (1) exponentially increasing demand and (2) Verhult's demand. While comparing, the total cost in Verhult's demand pattern is more profitable production process. A substantial numerical example is considered to investigate the effect of change in the total cost in both the demand function. A sensitivity analysis is developed to study the effect of changes in total cost.

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 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.

Modelling of critical factors for responsiveness in supply chain

2015 ◽  
Vol 26 (6) ◽  
pp. 868-888 ◽  
Author(s):  
Rajesh Kumar Singh
Keyword(s):  
Supply Chain ◽  
Inventory Management ◽  
Lead Time ◽  
Product Life Cycle ◽  
Strategy Development ◽  
Top Management ◽  
Critical Factors ◽  
Interpretive Structural Modeling ◽  
Content Type ◽  
Use Of Resources

Purpose – In globalized economy, product life cycle is reducing continuously, customers demands are changing fast, and lead time for response is decreasing. In such scenario, ability of firms to quickly respond to changes in their external environment is a primary determinant of firm’s performance. This can be only possible when whole of the supply chain (SC) is responsive. For this, firms have to manage internal operations effectively to enable SC, responsive for market requirements. The purpose of this paper is to identify different factors for responsive SC. Design/methodology/approach – Based on literature review, total 17 critical factors for the responsive SC have been identified. Some of these factors are process oriented and some are result oriented. To develop structural relationship among these factors from strategic perspective, interpretive structural modeling (ISM) approach has been applied. Findings – It is observed that top management commitment, strategy development, resource development, use of technology, risk and reward sharing are major drivers for responsive SC. By managing these enablers, organizations can also benefit in terms of inventory management, lead time reduction and agility. Research limitations/implications – ISM has got some limitations. Major limitation is that the relationships developed are subjective and there are chances of biasing. Therefore findings need to be validated with case studies and empirical findings. Practical implications – Top management should strive for effective use of resources and technology to improve SC capabilities to meet market changes. Originality/value – This study develops structural relationships between different factors and it will help organizations in taking initiatives for improving responsiveness.

scholarly journals A two-warehouse inventory model with increasing demand and time varying deterioration

2012 ◽  
Vol 19 (6) ◽  
pp. 1969-1977 ◽  
Author(s):  
B. Kumar Sett ◽  
Biswajit Sarkar ◽  
A. Goswami
Keyword(s):  
Inventory Model ◽  
Time Varying ◽  
Increasing Demand
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