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.

scholarly journals An Inventory Model for Imperfect Quality Products with Rework, Distinct Holding Costs, and Nonlinear Demand Dependent on Price

Mathematics ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 1362
Author(s):  
Leopoldo Eduardo Cárdenas-Barrón ◽  
María José Lea Plaza-Makowsky ◽  
María Alejandra Sevilla-Roca ◽  
José María Núñez-Baumert ◽  
Buddhadev Mandal
Keyword(s):  
Optimal Solution ◽  
Inventory Model ◽  
Inventory System ◽  
Inventory Level ◽  
Selling Price ◽  
Lot Size ◽  
Inventory Models ◽  
Holding Costs ◽  
Imperfect Items ◽  
The Moment

Traditionally, the inventory models available in the literature assume that all articles in the purchased lot are perfect and the demand is constant. However, there are many causes that provoke the presence of defective goods and the demand is dependent on some factors. In this direction, this paper develops an economic order quantity (EOQ) inventory model for imperfect and perfect quality items, taking into account that the imperfect ones are sent as a single lot to a repair shop for reworking. After reparation, the items return to the inventory system and are inspected again. Depending on the moment at which the reworked lot arrives to the inventory system, two scenarios can occur: Case 1: The reworked lot enters when there still exists inventory; and Case 2: The reworked lot comes into when the inventory level is zero. Furthermore, it is considered that the holding costs of perfect and imperfect items are distinct. The demand of the products is nonlinear and dependent on price, which follows a polynomial function. The main goal is to optimize jointly the lot size and the selling price such that the expected total profit per unit of time is maximized. Some theoretic results are derived and algorithms are developed for determining the optimal solution for each modeled case. It is worth mentioning that the proposed inventory model is a general model due to the fact that this contains some published inventory models as particular cases. With the aim to illustrate the use of the proposed inventory model, some numerical examples are solved.

EOQ MODEL FOR TIME-DEPENDENT DETERIORATION RATE WITH A TEMPORARY PRICE DISCOUNT

2005 ◽  
Vol 22 (04) ◽  
pp. 479-485 ◽  
Author(s):  
BHAVIN J. SHAH ◽  
NITA H. SHAH ◽  
Y. K. SHAH
Keyword(s):  
Fruits And Vegetables ◽  
Price Policy ◽  
Inventory System ◽  
Price Discount ◽  
Marginal Value ◽  
Deterioration Rate ◽  
Eoq Model ◽  
Holding Cost ◽  
The Difference ◽  
Inventory Holding

Deterioration is defined as decay, damage, spoilage, evaporation, obsolescence, pilferage, and loss of utility or loss of marginal value of a commodity that reduces usefulness from original ones. Blood, fish, fruits and vegetables, alcohol, gasoline, radioactive chemicals, medicines, etc., lose their utility with respect to time. In this case, a discount price policy is implemented by the suppliers of these products to promote sales. In this study, a mathematical model is developed for an inventory system that considers a temporary price discount when commodities in an inventory system are subject to deterioration with respect to time. Our goal in this article is to maximize the difference between two costs (gain) — taking advantage of price discount by ordering a large quantity, which in turn increases inventory holding cost as well deterioration cost and by not ordering a large quantity at a discounted price. An attempt is made to find bounds on the beneficial discount rate. The model is supported with a numerical example.

Multi-Location Inventory Model Considering Bidirectional and Unidirectional Transshipments Simultaneously

2013 ◽  
Vol 694-697 ◽  
pp. 2742-2745
Author(s):  
Jin Hong Zhong ◽  
Yun Zhou
Keyword(s):  
Process Model ◽  
Approximate Calculation ◽  
Inventory Model ◽  
Inventory System ◽  
Death Process ◽  
Birth And Death Process ◽  
Inventory Models ◽  
Continuous Review ◽  
Poisson Demand ◽  
Queue Theory

Abstract. A cross-regional multi-site inventory system with independent Poisson demand and continuous review (S-1,S) policy, in which there is bidirectional transshipment between the locations at the same area, and unidirectional transshipment between the locations at the different area. According to the M/G/S/S queue theory, birth and death process model and approximate calculation policy, we established inventory models respectively for the loss sales case and backorder case, and designed corresponding procedures to solve them. Finally, we verify the effectiveness of proposed models and methods by means of a lot of contrast experiments.

On Several types of universal invariants of framed links and 3-manifolds derived from Hopf algebras

2007 ◽  
Vol 142 (1) ◽  
pp. 73-92
Author(s):  
JIANJUN PAUL TIAN
Keyword(s):  
Representation Theory ◽  
Hopf Algebras ◽  
Comparison Study ◽  
Comprehensive Comparison ◽  
The Difference

AbstractWithout using representations of quasitriangular ribbon Hopf algebras, Hennings, Kauffman and Radford, Ohtsuki and the author gave different methods to construct invariants of links and 3-manifolds respectively. To understand these different methods and the resultant invariants, we made a comprehensive comparison study in this paper. We show the relations among the universal invariants of framed links defined by these different authors. We also figured out the relations among the resultant invariants of 3-manifolds defined by these different authors. Ignoring the difference by scalar constants and the inversion of Hopf algebras, we found that the invariants of 3-manifolds obtained by these authors are the same or equivalent to each other. Therefore, in a sense, there is only one way to construct invariants of 3-manifolds without using representation theory of Hopf algebras.

scholarly journals Retailer’s optimal ordering policies for EOQ model with imperfective items under a temporary discount

2016 ◽  
Vol 26 (2) ◽  
pp. 219-240
Author(s):  
Wen Lin ◽  
Horng Chang
Keyword(s):  
Economic Order Quantity ◽  
Order Quantity ◽  
Objective Functions ◽  
Inventory Models ◽  
Screening Process ◽  
Numerical Examples ◽  
Closed Form Solutions ◽  
Eoq Model ◽  
Optimal Ordering ◽  
Special Order

In this article, we study inventory models to determine the optimal special order and maximum saving cost of imperfective items when the supplier offers a temporary discount. The received items are not all perfect and the defectives can be screened out by the end of 100% screening process. Three models are considered according to the special order occurs at regular replenishment time, non-regular replenishment time, and screening time of economic order quantity cycle. Each model has two sub-cases to be discussed. In temporary discount problems, in general, there are integer operators in objective functions. We suggest theorems to find the closed-form solutions to these kinds of problems. Furthermore, numerical examples and sensitivity analysis are given to illustrate the results of the proposed properties and theorems.

An Imperfect Production Model for Breakable Multi-Item with Dynamic Demand and Learning Effect on Rework over Random Planning Horizon

2021 ◽  
Vol 14 (12) ◽  
pp. 574
Author(s):  
Amalesh Kumar Manna ◽  
Leopoldo Eduardo Cárdenas-Barrón ◽  
Barun Das ◽  
Ali Akbar Shaikh ◽  
Armando Céspedes-Mota ◽  
...  
Keyword(s):  
Learning Effect ◽  
Planning Horizon ◽  
Inventory Model ◽  
Inventory System ◽  
Production Model ◽  
Inventory Models ◽  
Imperfect Production ◽  
Production Inventory ◽  
Random Planning Horizon ◽  
Production Inventory System

In recent times, in the literature of inventory management there exists a notorious interest in production-inventory models focused on imperfect production processes with a deterministic time horizon. Nevertheless, it is well-known that there is a high influence and impact caused by the learning effect on the production-inventory models in the random planning horizon. This research work formulates a mathematical model for a re-workable multi-item production-inventory system, in which the demand of the items depends on the accessible stock and selling revenue. The production-inventory model allows shortages and these are partial backlogged over a random planning horizon. Also, the learning effect on the rework policy, inflation, and the time value of money are considered. The main aim is to determine the optimum production rates that minimize the expected total cost of the multi-item production-inventory system. A numerical example is solved and a detailed sensitivity analysis is conducted in order to study the production-inventory model.

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