• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.38 no.2
• /
• pp.145-151
• /
• 2015

As order quantity is increased, the ordering cost per item will be cheaper due to saving of transportation and material handling costs. In this paper, two realistic assumptions such as quantity discount and budget limit are considered. Quantity discount means that all units in the order will be discounted according to the predetermined order levels. Budget limit represents that the costs for inventory investments are bounded. This paper develops a Lagrangian relaxation approach for a continuous review inventory model with a budget constraint and quantity discounts. Computational results indicate that the proposed approach provides a good solution. Sensitivity analysis is done to get some insights on budget limit and quantity discount. As budget limit or the amount of discount according to order quantity is increased, order quantity is increased, whereas reorder point is not always increased.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.32 no.4
• /
• pp.53-62
• /
• 2009

Lee[15] examined quantity discount contracts between a manufacturer and a retailer in a stochastic, two-period inventory model where quantity discounts are provided based on the previous order size. During the two periods, the retailer faces stochastic (truncated Poisson distributed) demands and he/she places orders to meet the demands. The manufacturer provides for the retailer a price discount for the second period order if its quantity exceeds the first period order quantity. In this paper we extend the above two-period model to a k-period one (where k < 2) and propose a stochastic nonlinear mixed binary integer program for it. In order to make the program tractable, the nonlinear term involving the sum of truncated Poisson cumulative probability function values over a certain range of demand is approximated by an i-interval piecewise linear function. With the value of i selected and fixed, the piecewise linear function is determined using an evolutionary algorithm where its fitness to the original nonlinear term is maximized. The resulting piecewise linear mixed binary integer program is then transformed to a mixed binary integer linear program. With the k-period model developed, we suggest a solution procedure of receding horizon control style to solve n-period (n < k) order decision problems. We implement Lee's two-period model and the proposed k-period model for the use in receding horizon control style to solve n-period order decision problems, and compare between the two models in terms of the pattern of order quantities and the total profits. Our computational study shows that the proposed model is superior to the two-period model with respect to the total profits, and that order quantities from the proposed model have higher fluctuations over periods.

• Proceedings of the Safety Management and Science Conference
• /
• 2002.05a
• /
• pp.237-241
• /
• 2002

This paper deals with the problem of determining the buyer's economic lot sizing policy for exponentially deteriorating products under trade credit. It is also assumed that the ordering cost consists of a fixed set-up cost and a freight cost, where the freight cost has a quantity discount offered due to the economies of scale. We formulate the mathematical model and the solution algorithm is developed based on the properties of an optimal solution.

• International Journal of Advanced Culture Technology
• /
• v.9 no.3
• /
• pp.271-276
• /
• 2021

In this paper we analyze the effect of the credit period on inventory policy under trade credit with ordering cost including a fixed cost and freight cost, where the freight cost has a quantity discount. For marketing purposes, some supplier offers credit period to his buyer to stimulate the demand for the product he produces. The delay in payments during the credit period has the effect of reducing the buyer's capital opportunity cost. It is also assumed that the buyer pays the freight cost for the order and hence, the ordering cost consists of a fixed ordering cost and a variable freight cost which depends on the order quantity. As a result, the possibilities of trade credit and discounts on freight costs are expected to play an important role in the buyer's inventory policy. Based on the economic order quantity inventory model, we analyze how the buyer can determine the optimal inventory policy and we examine the effect of the length of credit period on the buyer's inventory policy.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.15 no.26
• /
• pp.33-42
• /
• 1992

최근 제조공정상의 학습효과를 고려한 통합로트량 결정모형이 개발되었다. 본 논문은 기존의 단일 구매자에서 복수구매자의 모델로 확장된 가격할인 모형을 다룬다. 이 모형에서는 복수구매자의 발주간격은 가장 짧은 구매자의 발주간격에 정수배라는 가정하에서 모형이 개발되었다. 구매자의 계수변화로 인한 민감도 분석이 되었다. 소개된 모형의 효과를 보이기 위해 수치예재를 이용하였다.

• Journal of the Korea Safety Management & Science
• /
• v.8 no.1
• /
• pp.195-206
• /
• 2006

본 연구는 제조자(공급자)와 중간분배자로 구성된 공급사슬에서 시간에 따라 일정률로 퇴화하는 퇴화성 제품을 다루는 중간분배자의 신뢰성있는 재고보충정책을 분석하였다. 문제 분석을 위하여 제조자는 고객의 수요를 증대시키기 위한 수단으로 중간분배자로부터의 제품대금에 대하여 일정기간 동안 신용거래를 허용한다는 가정과 함께 수송량에 따라 할인되는 수송비를 고려하여 모형을 수립하였고, 중간분배자의 경제적 재고보충정책을 결정하기 위한 해법을 개발하였다.

• Journal of the Korea Safety Management & Science
• /
• v.2 no.4
• /
• pp.209-217
• /
• 2000

In this paper, we consider an Inventory system with multi-suppliers. A supply agreement is made with one of the suppliers, to deliver a fixed quantity Q evry review period ； That is, adapting to discounts of under the condition of free addition often implies that the timing and sizes of future replenishment orders are less predetermined. The replenishment decisions for the other supplier are governed by a replenishment policy. This paper, multiple suppliers strategy is a combination of a push system (the main supplier delivers every review period a predetermined quantity Q) and a pull system the replenishment orders placed at other suppliers are governed by replenishment policy. The costs are defined as the sum of the ordering, holding, purchasing and opportunity costs. Based on numerical results, conclusions follow about the division of the replenishment volume among the inventory policy.

• Industrial Engineering and Management Systems
• /
• v.6 no.2
• /
• pp.136-145
• /
• 2007

The selection of suppliers and the determination of order quantities to be placed with those suppliers are important decisions in a supply chain. In this research, a non-linear mixed integer programming model is presented to select suppliers and determine the order quantities. The model considers the purchasing cost which takes into account quantity discount, the cost of transportation, the fixed cost for establishing suppliers, the cost for holding inventory, and the cost of receiving poor quality parts. The capacity constraints for suppliers, quality and lead-time requirements for the parts are also taken into account in the model. Since the purchasing cost, which is a decreasing step function of order quantities, introduces discontinuities to the non-linear objective function, it is not easy to employ traditional optimization methods. Thus, a heuristic algorithm, called particle swarm optimization (PSO), is used to find the (near) optimal solution. However, PSO usually generates initial solutions randomly. To improve the PSO solution quality, a heuristic procedure is proposed to find an initial solution based on the average unit cost including transportation, purchasing, inventory, and poor quality part cost. The results show that PSO with the proposed initial solution heuristic provides better solutions than those with PSO algorithm only.

• Journal of Distribution Research
• /
• v.1 no.2
• /
• pp.9-28
• /
• 1996

Recent research has examined how changing a buyer's purchasing policy can improve the efficiency of buyer-seller transactions for a single product. This paper extends the analysis to consider transactions involving multiple products. We show that under certain conditions, coordinating purchases across products is more efficient for the buyer and the seller than maximizing transctions efficiency for each separate product. In contrast to the single product case, the original prices of the products sometimes can support efficient, coordinated transactions across products. Mechanisms like quantity discounts, which are necessary to enforce efficient transactions for a single product, are therefore not always necessary for efficient, coordinated transactions of multiple products. When such mechanisms are required, we show that product bundling by the seller can be used to maximize transactions efficiency across products.

• Culinary science and hospitality research
• /
• v.20 no.1
• /
• pp.189-204
• /
• 2014

This study is aimed to identify the relationship between Korean restaurant selection attributes and behavioral intention regarding foodservice consumption tendency. In order to achieve the purpose of research, frequency analysis, factor and reliability analysis, correlation analysis, cluster analysis, chi-square test, variance analysis, and multiple regression analysis were conducted using SPSS 18.0. As a result of variance analysis, accessibility did not appear to have a significant difference in all clusters, food quality appeared to have a significant result (F=5.587, $p{\leq}.001$), employees' service appeared to have a significant difference (F=5.186, p<.01), and price discounts also showed a significant difference (F=4.921, p<.01). Therefore, the first hypothesis that the foodservice consumption tendency has a difference in the Korean restaurants selection attributes was partially selected. In order to verify the hypothesis that the Korean restaurants selection attributes affect behavioral intention, the sub-factors of the Korean restaurant selection attributes (accessibility of restaurants, food quality, employees' service, price discounts) were set as independent variables, and the behavioral intention of foodservice consumers was set as a dependent variable. As a result, the accessibility of restaurants (${\beta}=.092$) and price discounts (${\beta}=.299$) have a non-significant effect on behavioral intention. However, a significant result was shown in food quality (${\beta}=.379$, p<.001) and employees' service (${\beta}=.251$, p<.001). Thus, the hypothesis that the Korean restaurant selection attributes have a positive effect on behavioral intention was partially selected. Based on the results, foodservice managers need to build up strategic management to improve food quality with better ingredients, sanitation, adequate quantity, and consistent taste of food. In addition, they should provide better service with well-trained employees.