scholarly journals Developing a Model with Ergonomic Aspects Using Endurance Time and Rest Allowance for Supporting the Optimization of Production Line Material Supply: A Case of Single-Operator Multi-Materials

2021 ◽  
Vol 2021 ◽  
pp. 1-25
Author(s):  
Sezen Korkulu ◽  
Krisztián Bóna ◽  
Tamás Péter
Keyword(s):  
Inventory Management ◽  
Environmental Sustainability ◽  
Production Line ◽  
Inventory Model ◽  
Numerical Work ◽  
Endurance Time ◽  
Line Material ◽  
Material Supply ◽  
Single Operator ◽  
Time Contraction

Various studies on the issues regarding economic and environmental sustainability in inventory management have been investigated by many researchers in recent years. However, the integration of ergonomics as an aspect of social sustainability in an inventory model is still scarce. This paper presents an extension of ergonomic inventory modeling with a new mathematical model which integrates relaxation allowance and endurance time to the ergonomic inventory model. The rest allowance is determined by endurance time, contraction time, and relative force based on several items such as weight, and it helps to prevent ergonomic risks and fatigue of the back muscles. The model has been analyzed in a numerical work based on our specific simulator and parameteric analysis to present validness in different scenarios. Consequently, our results show that optimization with ergonomics in production line material supply provides notable advantages as it increases overall productivity.

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.

Current Practices in Log Yard Design and Operations in the Province of Quebec, Canada

2019 ◽  
Vol 69 (4) ◽  
pp. 248-259
Author(s):  
Marta Trzcianowska ◽  
Daniel Beaudoin ◽  
Luc LeBel
Keyword(s):  
Inventory Management ◽  
Scientific Literature ◽  
Raw Material ◽  
Design Management ◽  
Surface Material ◽  
Material Supply ◽  
Industrial Sectors ◽  
Potential Gain ◽  
Forest Supply Chain ◽  
Current Practices

Abstract Log yards play an important role in the forest supply chain by connecting raw material supply to manufacturing processes. Log yard design and operations have not been thoroughly represented in the scientific literature, though research in other industrial sectors has demonstrated the strategic operational importance of warehouses. This article investigates the log yard design and operations in current industrial practices. An analysis of existing log yards was conducted in Quebec. Detailed information about throughput, equipment, personnel, inventory management, and design considerations was gathered by means of questionnaires, on-site visits, and meetings with yard managers. The survey of current practices (design, management, and operations) confirms that most existing yards have been designed without a systematic method. Crucial performance inhibitors included log yard shape, in-flow management, and poor surface material. Results point toward a potential gain in competitiveness by improving log yard practices, optimizing log yard shape and layout, better coordinating the forest–mill operations, and enhancing surface material.

An (s, S) Inventory Optimization Problem

2019 ◽  
pp. 187-206
Author(s):  
Gizem Sağol ◽  
Görkem Sariyer ◽  
Banu Yetkin Ekren ◽  
Mustafa Gökalp Ataman
Keyword(s):  
Inventory Management ◽  
Optimization Problem ◽  
Service Level ◽  
Inventory Model ◽  
Considerable Effort ◽  
Medical Products ◽  
High Service ◽  
Inventory Optimization ◽  
Medical Supplies

Inventory management is one essential lever to use the resources efficiently. However, managing inventories in hospitals is a challenging task because of the several issues: a high service level of medical supplies is required under the unpredictable demand, medical products constitute a significant portion of the overall costs, and the management of these supplies requires considerable effort to check the levels to track usage and to distribute them. Therefore, it is pertinence to apply operations research tools to cope with the managerial issues of the hospital inventory system. In this chapter, the authors implement an (s, S) inventory model by using simulation in a case study of a hospital in Izmir, Turkey. They aim to analyze the unpredictable nature of demand of medical supplies in this hospital and its implications on the developed inventory policy.

scholarly journals An Inventory Model based on Manufacturer-Direct Business Model with the help of E-Commerce Trading Strategies

2019 ◽  
Vol 8 (6S4) ◽  
pp. 507-512
Keyword(s):  
Inventory Management ◽  
Business Model ◽  
Customer Relations ◽  
Inventory Model ◽  
Trading Strategies ◽  
Waste Generation ◽  
Model Based ◽  
Operation Costs ◽  
Proposed Model ◽  
Production And Operation

The significance of inventory management partake in the rapid growth and development of all organizations. Inventories impacts sales and revenues, customer relations, production and operation costs etc. On the other hand, online shopping became a trendy choice among the web-users, they can buy any product either through online market places or over web stores. The main intention of this paper is to develop an inventory model based on 'Manufacturer-direct' business model with the help of e-commerce trading strategies. Also this proposed model considered the process of recycling and disposal of deteriorating items over 3R approach . In order to maximize the profits and to minimize the waste generation, this model provides optimum values. Numerical examples are illustrated to validate the model.

scholarly journals Blood platelet bank inventory management: an approximate dynamic programming approach

2021 ◽  
Author(s):  
Usama S. Albdulwahab
Keyword(s):  
Inventory Management ◽  
Blood Platelets ◽  
Blood Platelet ◽  
Inventory Model ◽  
Blood Bank ◽  
Artificial Blood ◽  
Blood Types ◽  
Proposed Model ◽  
Supply Model ◽  
Right To Refuse

Blood platelets are precious and highly perishable; their supply and demand suffer from significant variation. Consequently, the inventory management of platelets is an actual, contemporary prob- lem of considerable human interest. Although many researchers have solved a plethora of inventory models, their solutions have faced various challenges. This dissertation models some of these chal- lenges, alongside expenses and stock levels. This dissertation is based on four key objectives: (1) to develop a blood platelet inventory model that can represent an actual blood bank inventory, while overcoming the problem's curse of dimensionality; (2) to look for the best issuing policy based on the proposed model that can serve different incoming blood platelet demands; (3) to analyze the effect of having a new, artificial blood platelet alongside the existing natural eight blood types; and (4) to enhance the proposed model for a dual-supplied regional blood platelet bank that serves a network of hospitals. Blood platelet inventory management model is a multi-period, multi-product model that considers the eight natural blood types with uncertain demand, and deterministic lead times, alongside the artificial platelet and patients right to refuse it. The study is supported by both a review of literature and a testing data provided by the Canadian Blood Service. The findings show that modeling blood platelet inventory management, including the eight blood types and their ages, represents the actual-life model without any need for downsizing. It also leads to significantly reductions in shortages and outdates while increasing reward gained and maintaining minimal inventory levels. Compared to a single supply model, the dual supply model give less shortage and outdate rates. The regional blood bank inventory model considers the fact that patients have the right to refuse transfusion using artificial blood platelets. Finally, if the percentage of artificial supply in the inventory is more than 30% and the rate of patient acceptance is more than 30%, then both outdate and shortage percentages are below 1%.

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.

Aligning Aggregate Planning with (s,S) Inventory Model in a Stochastic Demand Environment

2018 ◽  
Vol 9 (1) ◽  
pp. 29-44 ◽  
Author(s):  
Shantanu Shankar Bagchi ◽  
Rik Paul
Keyword(s):  
Inventory Management ◽  
Demand Uncertainty ◽  
Stochastic Demand ◽  
Model System ◽  
Inventory Model ◽  
Periodic Review ◽  
Supplier Relationships ◽  
Long Run ◽  
Monitoring Costs ◽  
Review Model

Designing an aggregate plan is essential for firms to improve the efficiency of their inventory management as well as maintaining supplier relationships over a long run. Aggregate plan is primarily a function of demand uncertainty and the inventory policy in place. Firms tend to follow either a periodic review model ( system) or a perpetual model ( system) for managing inventory time to time; the former being more prevalent due to lower inventory monitoring costs associated. The article proposes a mathematical model that incorporates the principles of inventory model in deciding on the key components of an aggregate plan for each period in a multi-period stochastic demand environment for both stationary and non-stationary demand scenarios. The article also provides numerical illustrations to demonstrate the application of the model.

An Inventory Model for International Inventory Management

1985 ◽  
Vol 30 (3) ◽  
pp. 245-268
Author(s):  
Thomas O. Boucher ◽  
William E. Stuckey ◽  
Layek Abdel-Malek
Keyword(s):  
Inventory Management ◽  
Inventory Model

Study on Order Policies of Fresh Food Base on Safety Reliability

2012 ◽  
Vol 452-453 ◽  
pp. 853-857
Author(s):  
Yi Feng Zou ◽  
Ru He Xie
Keyword(s):  
Inventory Management ◽  
Inventory Model ◽  
Cold Chain ◽  
Fresh Food ◽  
Demand Rate ◽  
Ordering Policies

According to the characteristics of fresh food inventory management, an inventory model of fresh food is established based on the safety reliability of food cold chain logistics. Through solving the model and comparing the solutions, three important ordering policies of fresh food are gained. First, the greater the requirement of safety of fresh food is, the shorter its order cycle. Second, the higher the demand rate of fresh food is, the shorter its order cycle. Third, the better the condition of inventory is, the longer its order cycle.

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