Investigating the effect of inflation on an inventory system for defective items with inspection errors, sales returns and shortages

2021 ◽  
Vol 11 (2/3) ◽  
pp. 1
Author(s):  
Aditi Khanna ◽  
Aakanksha Kishore
Keyword(s):  
Inventory System ◽  
Defective Items ◽  
Inspection Errors

scholarly journals Inventory control in a two-level supply chain with learning, quality and inspection errors

2021 ◽  
Author(s):  
Mehmood Khan
Keyword(s):  
Supply Chain ◽  
Product Quality ◽  
Inventory Management ◽  
Human Error ◽  
Threshold Value ◽  
Process Quality ◽  
Lot Size ◽  
Defective Items ◽  
Inspection Errors ◽  
Screening Cost

A common measure of quality for a buyer or a vendor is the defect rate. Defects may represent an attribute, a dimension or a quantity. They may be classified as product quality defects or process quality defects. Product quality defects may be caused by human error which can de due to fatigue, lack of proper training, or other reasons. For example, an inspector may misclassify a defective fuel tank of a car as good. On the other hand, process quality defects maybe caused by a machine going out-of-control. While many researchers assume that the screening processes which separate the defective items are error-free, it would be realistic to consider misclassification errors in this process. Beside inspection errors, learning is another human factor that brings in enhancement in the overall performance of a supply chain. Learning is inherent when there are workers involved in a repetitive type of production process. Learning and forgetting are even more important in manufacturing environments that emphasize on flexibility where workers are cross-trained to do different tasks and where products have a short life cycle. Inventory management with learning in quality, inspection and processing time will be the focus of this thesis. A number of models will be developed for a buyer and/or a two level supply chain to incorporate these human factors. The key findings of this work may be summarized as 1. Inspection errors significantly affect the annual profit. 2. An increase in the unit screening cost reduces the annual profit to a great extent at slower rates of learning. 3. For the two-level supply chain we investigated, learning in production drops the annual cost significantly while the learning in supplier's quality results in a situation where there are no defectives from the suppliers. 4. Type II error may seem to be beneficial for a two level supply chain as the order/lot size goes down and thus affects the costs of ordering, production and screening. 5. Consignment stocking policy performs better than conventional stocking when holding costs go higher than a threshold value.

scholarly journals Inventory Modeling for Imperfect Production Process with Inspection Errors, Sales Return, and Imperfect Rework Process

2017 ◽  
Vol 2 (4) ◽  
pp. 242-258 ◽  
Author(s):  
Aditi Khanna ◽  
Aakanksha Kishore ◽  
Chandra K. Jaggi
Keyword(s):  
Customer Service ◽  
Real Life ◽  
Type I ◽  
Defective Items ◽  
Optimal Production ◽  
Human Errors ◽  
Inspection Errors ◽  
Production Policy ◽  
Good Customer Service ◽  
Rework Process

In real life, due to certain machine problems, process deterioration and many other factors, production processes deliver imperfect quality items. So, the effect of these defectives cannot be ignored in terms of ensuring good customer service. In order to sustain today’s cut-throat competition, rework process of defective items becomes a rescue to compensate for the imperfections present in the production system. The present model attempts to explore the traditional imperfect environment with a more practical approach by incorporating the concept of inspection errors, along with an imperfect rework process. By considering human errors as unavoidable, Type-I and Type-II errors are also incorporated in the study. To prioritize on the customer satisfaction level, Sales returns are given full price refunds. An analytical method is employed to maximize the expected total profit per unit time to study the combined effect of aforementioned factors on the optimal production quantity. A numerical example along with a comprehensive sensitivity analysis has been presented to demonstrate the applicability of the model and also to observe the effects of key parameters on the optimal production policy respectively. The pertinence of the model can be found in most manufacturing industries like textile, electronics, furniture, footwear, crockery etc.

scholarly journals A Comparison of Different Shipment Policies in an Integrated Inventory System for Imperfect Quality Items with Inspection Errors

2017 ◽  
Vol 2017 ◽  
pp. 1-17
Author(s):  
Yongwu Zhou ◽  
Xiong Zhang ◽  
Zhaozhan Lin
Keyword(s):  
Inventory System ◽  
Inventory Models ◽  
Screening Process ◽  
Inspection Errors ◽  
Holding Costs ◽  
Integrated Inventory ◽  
Comprehensive Comparison ◽  
The Difference ◽  
Inventory Holding ◽  
Single Batch

Considering a production-ordering system where items are not perfect and quality screening is conducted with inspection errors, we develop integrated inventory models under different shipment policies and make a comprehensive comparison among them to select an optimal one, so as to improve the supply chain’s performance. It is assumed that all items classified as defective during the screening process are sold as a single batch at a discounted price at the end of this screening process; items returned from the market are accumulating; and all of them are stored and sold as a single batch at a discounted price at the end of the next screening process. All the numerical results show that the proportional size shipment policy is always optimal, except for one situation where the difference between the vendor’s and the buyer’s unit inventory holding costs is considerably large. Therefore, we mainly recommend the proportional size shipment policy.

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