• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.18 no.35
• /
• pp.39-46
• /
• 1995

This study is to find the optimal lot size method in the distribution system. In general, the lot size methods used in the distribution system is the same as the methods of the MRP system. The lot size methods used in this study are LFL, EoQ, LTC and POQ.. Resulting in case study, LTC is the optimal lot size method in the distribution system. In distribution system, VRP and VSP shall be investgated.

• Journal of Korean Institute of Industrial Engineers
• /
• v.20 no.2
• /
• pp.3-17
• /
• 1994

This paper presents an EMQ model which determines an optimal manufacturing lot size in an unreliable machine. The machine has an exponentially distributed life time, and requires a constant time to repair when it fails. We 1) derive an average cost function, 2) obtain an optimal lot size and show that it is unique, 3) carry out sensitivity analysis to examine the effect of machine parameters (life time, time to repair) to optimal lot size.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.20 no.2
• /
• pp.95-107
• /
• 1995

This paper deals with the problem of determining optimal credit period and production lot size from the perspective of producer. We assume that a ratailer jointly determines the unit retail price and order size to maximize profit when he/she puechases a product for which the producer offers a trade credit. Two widely used demand functions are adopted for the study in which demands are decreasing function of the retail price. Mathematical models for producer-retailer system are developed and a solution procedure is presented which show how to achieve an optimal length of trade credit and production lot size for producer. The effect of production rate on the behavior of both producer and retailer is also investigated using an example.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.17 no.32
• /
• pp.177-186
• /
• 1994

Economic Lot size decision is studied on this thesis foe the muti-product small batch production system. Even though economic lot size decision has been studied for the MRP system. this could be applied at the industry under the multi-product small batch production system because of very complicate and manager's lack of understand. Therefore, this technique is applied at the industry in order to minimize ordering cosy based on optimal quantity and period, and holding cost according to optimize inventory level under the muti-product small batch production system. After that, lot size decision technique is compared with lot size decision technique which has been used for analyzing and emphasizing productivity

• Journal of Institute of Control, Robotics and Systems
• /
• v.20 no.7
• /
• pp.750-755
• /
• 2014

Product shortage which causes backordering and/or lost sales cost is very popular in chemical industries, especially in commodity polymer business. This study deals with backordering cost in the supply chain optimization model under the framework of process-inventory network. Classical economic order quantity model with backordering cost suggested optimal time delay and lot size of the final product delivery. Backordering can be compensated by advancing production/transportation of it or purchasing substitute product from third party as well as product delivery delay in supply chain network. Optimal solutions considering all means to recover shortage are more complicated than the classical one. We found three different solutions depending on parametric range and variable bounds. Optimal capacity of production/transportation processes associated with the product in backordering can be different from that when the product is not in backordering. The product shipping cycle time computed in this study was smaller than that optimized by the classical EOQ model.

• Journal of Institute of Control, Robotics and Systems
• /
• v.3 no.5
• /
• pp.532-541
• /
• 1997

This article derives an analytic solution to determine the optimal size of multiple noncontinuous process and storage units. The total cost to be minimized consists of the setup cost of noncontinuous processing units and the inventory holding cost of feedstock/product storages. A novel approach, which is called PSW(Periodic Square Wave) model, is applied to represent the material flow among non-continuous units and storages. PSW model presumes that the material flow between unit and storage is periodic square wave shaped. The resulting optimal unit size has similar characteristics with the classical economic lot sizing model such as EOQ(Economic Order Quantity) or EPQ(Economic Production Quantity) model in a sense that the unit size is determined as the balance between setup and inventory holding cost. However, the influence of inventory holding cost of PSW model is different from that of EOQ/EPQ model. EOQ/EPQ model includes only the product inventory holding cost but PSW model includes all inventory holding costs around the non-continuous unit with proportional contribution. PSW model is suitable for analyzing interlinked process-storage system. The optimal lot size of PSW model is smaller than that of EOQ/EPQ model. This is quitea remarkable result considering that the EOQ/EPQ model has been is widely used since last half century.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.21 no.2
• /
• pp.169-175
• /
• 2021

The lot sizing problem(LSP) is a hard problem that classified as non-deterministic(NP)-complete because of the polynomial-time optimal solution algorithm is unknown yet. The well-known W-W algorithm can be obtain the solution within polynomial-time, but this algorithm is a very complex, therefore the heuristic approximated S-M algorithm is suggested. This paper suggests O(n) linear-time complexity algorithm that can be find not the approximated but optimal solution. This algorithm determines the lot size Xt∗ in period t to the sum of the demands of interval [t,t+k], the period t+k is determined by the holding cost will not exceed setup cost of t+k period. As a result of various experimental data, this algorithm finds the optimal solution about whole data.

• IE interfaces
• /
• v.10 no.1
• /
• pp.47-55
• /
• 1997

This paper deals with an assembly process of the TFT glasses and the color filters in LCD manufacturing. Two specific problems are presented and solved. One is a matching problem to find the best matches between a set of TFT glasses and a set of color filters, which result in the maximum number of good LCD assemblies. A simple mathematical model is constructed for this problem and an optimal solution can be obtained using an existing algorithm. The other is a main problem that requires a determination of an economic lot size of the color filters which are going to be assembled with a given set of TFT glasses. A Bayesian dynamic forecasting model is developed to predict the defective patterns of color filters. Based on the predicted defective rate of color filters, the minimum lot size of the color filters can be determined to minimize the probability of losing good TFT glasses and color filters.

• Proceedings of the Safety Management and Science Conference
• /
• 2000.05a
• /
• pp.77-86
• /
• 2000

This paper deals with the problem of determining the retailer's optimal price and order size under the condition of order-size-dependent delay in payments. It is assumed that the length of delay is a function of the retailer's total amount of purchase. The constant price elasticity demand function is adopted which is a decreasing function of retail price. Investigation of the properties of an optimal solution allows us to develop an algorithm whose validity is illustrated through an example problem.

• International Journal of Advanced Culture Technology
• /
• v.8 no.1
• /
• pp.62-70
• /
• 2020

As an effective means of price discrimination, some suppliers offer trade credit to the distributors in order to stimulate the demand for the product they produce. The availability of the delay in payments from the supplier enables discount of the distributor's selling price from a wider range of the price option in anticipation of increased customer's demand. Since the distributor's lot-size is affected by the demand for the customer, the distributor's lot-size and the selling price determination problem is interdependent and must be solved at the same time. Also, in many common business transactions, the distributor pays the shipping cost for the order and hence, the distributor's ordering cost consists of a fixed ordering cost and the shipping cost that depend on the order quantity. In this regard, we deal with the joint lot-size and price determination problem when the supplier allows delay in payments for an order of a product. The positive effects of credit transactions can be integrated into the EOQ (economic order quantity) model through the consideration of retailing situations, where the customer's demand is a function of the distributor's selling price. It is also assumed that the distributor's order cost consists of a fixed ordering cost and the variable shipping cost. We formulate the distributor's mathematical model from which the solution algorithm is derived based on properties of an optimal solution. A numerical example is presented to illustrate the algorithm developed.