Note on “Effects of Random Defective Rate and Imperfect Rework Process on Economic Production Quantity Model”

2005 ◽  
Vol 128 (1) ◽  
pp. 375-377 ◽  
Author(s):  
Yuan-Shyi Peter Chiu ◽  
Singa Wang Chiu

Conventional approaches for deriving optimal production lot size are by using the differential calculus on the production-inventory cost function with the need to prove optimality first. Recent articles proposed the algebraic approach to the solution of classic economic order quantity and economic production quantity (EPQ) model without reference to the use of derivatives. This note extends it to an EPQ model taking the random defective rate and imperfect rework process into consideration. We demonstrate that the optimal lot size can be solved algebraically and the expected inventory cost can be derived immediately as well.

2016 ◽  
Vol 15 (1) ◽  
pp. 78 ◽  
Author(s):  
Nurike Oktavia ◽  
Henmaidi Henmaidi ◽  
Jonrinaldi Jonrinaldi

The most popular inventory model to determine production lot size is Economic Production Quantity (EPQ). It shows enterprise how to minimize total production cost by reducing inventory cost. But, three main parameters in EPQ which are demand, machine set up cost, and holding cost, are not suitable to solve issues nowadays. When an enterprise has two types of demand, continue and discrete demand, the basic EPQ would be no longer useful. Demand continues comes from a customer who wants their needs to be fulfilled every time per unit time, while the fulfillment of demand discrete is at a fixed interval of time. A literature review is done by writers to observe other formulation of EPQ model. As there is no other research can be found which adopt this topic, this study tries to develop EPQ model considering two types of demand simultaneously.


Author(s):  
Brojeswar Pal ◽  
Subhankar Adhikari

In this paper, we have developed an economic production quantity (EPQ) model in which production is executed mainly by the original machine. But when the system faces disruption, the buffer of it continues the production. Here, we incorporate a fixed Safe Period running policy, in which the machine runs interruptedly, whenever production commences.  The disruption of the system may occur at any moment of the time horizon over the safe period, and then, it will go under the corrective maintenance policy. Here, we take that both of the time of disruption and period of maintenance are continuous random variables. We have discussed the model under different safe period duration with corresponding disruption situations. Our main objective is to minimize the expected average total cost for all the cases concerning the production lot size. The model has also been illustrated numerically with some examples. To examine the robustness of the solution of this model, we discuss the sensitivity analysis for the parameters.


2006 ◽  
Vol 2006 ◽  
pp. 1-5 ◽  
Author(s):  
Yung-Fu Huang

Chiu studied the effect of service-level constraint on the economic production quantity (EPQ) model with random defective rate. In this note, we will offer a simple algebraic approach to replace his differential calculus skill to find the optimal solution under the expected annual cost minimization.


2008 ◽  
Vol 25 (03) ◽  
pp. 301-315 ◽  
Author(s):  
S. PANDA ◽  
S. SAHA ◽  
M. BASU

A single item, single cycle economic production quantity model for perishable products is proposed where the demand is two-component and stock dependent. The production inventory scenario of products like cake, bread, fast foods, fishes, garments, cosmetics etc in the festival season is considered. The profit function is formulated under the assumption that the time period of the festival seasons is fixed and the display capacity of the produced item is limited. In the formulation process, to introduce more flexibility, a goal programming technique is incorporated to achieve the producer's desired profit and stock of as much inventory as possible below the display capacity level. A numerical example is presented to illustrate the proposed model. A sensitivity analysis of the model is also carried out.


2006 ◽  
Vol 2006 ◽  
pp. 1-13 ◽  
Author(s):  
Yuan-Shyi Peter Chiu

We study the effect of service level constraint on the economic production quantity (EPQ) model with random defective rate. We first prove that the expected overall cost for imperfect quality EPQ model with backlogging permitted is less than or equal to that of the same model without backlogging. Secondly, the relationship between “imputed backorder cost” and maximal shortage level is derived for decision-making on whether the required service level is achievable. Then an equation is proposed for calculating the intangible backorder cost for the situation when the required service level is not attainable. By including this intangible backorder cost in the mathematical analysis, one can derive a new optimal lot-size policy that minimizes expected total costs as well as satisfies the service level constraint. Numerical example is provided to demonstrate its practical usage.


2020 ◽  
Vol 9 (3) ◽  
pp. 758
Author(s):  
Usman Ghani ◽  
Mubashir Hayat

Determining the optimal replenishment lot size and shipment policy for a production setup has been of greater interest during the last few years. This paper derives the optimal replenishment lot size and shipment policy for an Economic Production Quantity (EPQ) model with rework of defective items. However, in a real life situation, multi-shipment policy is used in lieu of continuous issuing policy and generation of defective items is inevitable. The proposed research assume that all imperfect quality items are reworked to perfect quality items and then all perfect quality items are delivered to the customers. Mathematical modeling is used in this study and the long-run average production–inventory-delivery cost function is derived. Convexity of the cost function is proved by using the Hessian matrix equations. The closed-form optimal replenishment lot size and optimal number of shipments that minimize the long-run average costs for such an EPQ model are derived.  


Matematika ◽  
2017 ◽  
Vol 16 (2) ◽  
Author(s):  
Farid H Badruzzaman ◽  
Erwin Harahap ◽  
Eti Kurniati ◽  
M. Deni Johansyah

Abstrak. Permasalahan dari persediaan adalah bagaimana menentukan jumlah produksi optimal dengan biaya total persediaan yang minimum. Sebuah persediaan dilakukan tidak lain dengan maksud mengantisipasi dan memenuhi permintaan yang akan datang. Penyimpanan persediaan dalam jangka waktu yang lama akan berdampak pada keusangan dan menurunnya kualitas, sehingga diperlukan perhitungan jumlah persediaan yang optimal. Model persediaan Economic Production Quantity (EPQ) merupakan suatu metode yang digunakan untuk mempertimbangkan jumlah produksi dan jumlah permintaan hasil produksi. Tujuannya adalah dengan menentukan banyaknya produksi yang meminimumkan total biaya persediaan. Penelitian ini bertujuan untuk menghitung jumlah produksi optimum pada perusahaan kerudung. Selama ini, jumlah produksi pada tahun 2017 dan sebelumnya berpedoman pada jumlah pesanan pelanggan ditambah 17,5% dari jumlah permintaan untuk cadangan persediaan. Hasil solusi optimum dengan model EPQ memiliki perbedaan yang signifikan dibandingkan dengan yang selama ini berlaku.Kata Kunci: economic production quantity, persediaan, produksiAbstract. The problem of inventory is how to determine the optimal amount of production with minimum total inventory cost. An inventory is carried out with no other intent to anticipate and meet future demand. Storage of inventory over a long period of time will have an impact on obsolescence and declining quality, so it is necessary to calculate the optimal amount of inventory. Model inventory Economic Production Quantity (EPQ) is a method used to consider the number of production and the number of production demand. The goal is to determine the amount of production that minimizes the total cost of inventory. This study aims to calculate the number of optimum production on the company's hood. So far, the number of production in 2017 and previously guided by the number of customer orders plus 17.5% of the total demand for inventory reserves. The results of the optimum solution with the EPQ model have significant differences compared to those currently in force.Keywords: economic production quantity, inventory, production


2018 ◽  
Vol 56 (18) ◽  
pp. 6279-6293 ◽  
Author(s):  
Luiza Ribeiro Alves Cunha ◽  
Ana Paula Santos Delfino ◽  
Kamila Almeida dos Reis ◽  
Adriana Leiras

2014 ◽  
Vol 556-562 ◽  
pp. 6616-6619
Author(s):  
Jun Chen ◽  
Lai Fu Ye

Based on Economic Production Quantity (EPQ) model with certain defective rate, this paper analyses technology patent storage problems in university-enterprise cooperation under the perspective of consumer electronics enterprise, finds out the optimal number and cycle of patent research considering the factor of research and development failure rate.


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