• The Journal of the Korea Contents Association
• /
• v.11 no.2
• /
• pp.88-100
• /
• 2011

This thesis suggests fixed quantity model and detailed performance procedures of an information system audit. In addition, an identification of the check-items with high operating risk and factors that might lead to serious effects on the business are made. Then, this thesis proposes the information system audit model that can grant priorities. By using this model, the orderer can evaluate objectively with digitized mark. The model can improve the effectiveness, reliability, and objectivity of the audit by minimizing the discrepancies of different opinions about audit evaluation results between auditee and the orderer. The proposed model is adapted to an application system and audit projects of the database construction. As a result, the model has received an equal mark from the result of the general reviews, thus the propriety of the proposed model was verified.

• Journal of Digital Convergence
• /
• v.9 no.5
• /
• pp.141-156
• /
• 2011

Auditors' subjective opinions m audit activities weaken reliability in audit judgments. This paper suggests fixed quantity models through requirement priority for improving objective evaluation and priorities of requirements in information system audit. The value of requirements was evaluated based on customers' requirements with a premise that they are not in the same level. Furthermore, the audit objective judgments were enhanced to enable fixed quantity of subjective audit by subdividing detailed evaluation index of requirement priority standards into importance of service and function on orderers' perspective, and sectioning cost and schedule on contractors' perspective.

• Proceedings of the Safety Management and Science Conference
• /
• 2004.11a
• /
• pp.447-451
• /
• 2004

Generally, Fixed Quantity ordering system (Q-system) uses linear model in inventory decrease. This paper focuses on that Fixed Quantity ordering system (Q-system) is based on a continuous review system. To use a continuous review system is because of an inventory decrease ration is not constant. Therefore, this paper introduces a method to select a model which is proper to virtual data under conditions which are inconstant.

• 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 the Korea Society for Simulation
• /
• v.10 no.1
• /
• pp.35-50
• /
• 2001

Managing multi-echelon inventory systems has gained importance over the last decade mainly because integrated control of supply chains consisting of several processing and distribution stages has become feasible through modern information technology. Determination of optimal inventory policy for multi-echelon supply chain is made difficult by the complex interaction between the different levels. In this paper, we investigate performance of five inventory policies (fixed quantity order policy, fixed interval order policy, compromised order policy, lead time-fixed quantity order policy, and mixed order policy) in a multi-echelon supply chain by using a simulation model constructed with AweSim simulation language. The results of the simulation study show that the mixed order policy is the best among five inventory policies in the most test problems except the case when the stockout cost per unit is much higher than the inventory holding and transportation costs per unit.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.20 no.42
• /
• pp.21-30
• /
• 1997

This research fundamentally deals with an analysis of service level for a multi-level inventory distribution system which is consisted of a central distribution center and several branches being supplied stocks from the distribution center, Under continuous review policy, the distribution center places an order for planned order quantity to an outside supplier, and the order quantity is received after a certain lead time. Also, each branch places an order for particular quantity to its distribution center, and receives the order quantity after a lead time. In most practical distribution environment, demands and lead times are generally not fixed or constant, but variable. And these variabilities make the analysis more complicated. Thus, the main objective of this research is to suggest a method to compute the service level at each depot, that is, the distribution center and each branch with variable demands and variable lead times. Further, the model will give an idea to keep the proper level of safety stocks that can attain effective or expected service level for each depot.

• Journal of the Korea Safety Management & Science
• /
• v.3 no.3
• /
• pp.65-75
• /
• 2001

This research fundamentally deals with an analysis of service level for a multi-level inventory distribution system which is consisted of a central distribution center and several branches being supplied stocks from the distribution center, Under continuous review policy, the distribution center places an order for planned order quantity to an outside supplier, and the order quantity is received after a certain lead time. Also, each branch places an order for particular quantity to its distribution center, and receives the order quantity after a lead time. In most practical distribution environment, demands and lead times are generally not fixed or constant, but variable. And these variabilities make the analysis more complicated. Thus, the main objective of this research is to suggest a method to compute the service level at each depot, that is, the distribution center and each branch with variable demands and variable lead times. Further, the model will give an idea to keep the proper level of safety stocks that can attain effective or expected service level for each depot.

• 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.

• Journal of Korean Institute of Industrial Engineers
• /
• v.34 no.1
• /
• pp.32-41
• /
• 2008

This paper studies a joint EOQ and EPQ model in which a stationary demand can be satisfied by recycled products as well as newly purchased products. The model assumes that a fixed quantity of the used products are collected from customers and later recovered for reuse. The recovered products are regarded as perfectly new ones. We also assume that the number of orders for newly purchasing items and the number of recovery setups in a cycle can be mutually independent integers. Under these assumptions, we develop an optimization model obtaining the economic order quantity for newly procured products, the optimal lot size for the recovery process, and the sequence of the orders and the setups, simultaneously. And then a simple solution procedure to find a local optimal control parameter set is proposed. To validate the model and the solution procedure, finally, some computational experiments are presented.