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

• Journal of Korean Society of Industrial and Systems Engineering
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• v.12 no.20
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• pp.77-80
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• 1989

A rectifying sampling plan which assumes a prior distribution on the lot percent defective is considered. This sampling is developed for finite lot size N with matching OC curves and generated from an initial plan selected from single sampling by attributes.

• Journal of the Korean Operations Research and Management Science Society
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• v.20 no.2
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• pp.95-107
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• 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
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• v.37 no.4
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• pp.231-238
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• 2014

Optimum lot size calculation for real world manufacturing environment has been focused since last few decades. Several extensions have been made to the basic economic order and production order quantity models to realize the possible practical situations in industry. However, focus on work-in-process inventory has been ignored relatively. This paper provides a comprehensive review of the models developed for group technology based manufacturing environment focusing on work-in-process inventory. Models have been extended from a perfect manufacturing conditions to an imperfect manufacturing situation considering rework, rejection and inspection. Optimum lot size has been evaluated using a simple algebraic optimization approach. Significant parameters are highlighted using sensitivity analysis for the developed models. Numerical example is used to illustrate the utilization of such models in day-to-day production setups and the impact of significant factors' variation on total cost and optimum lot size.

• Industrial Engineering and Management Systems
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• v.11 no.3
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• pp.288-298
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• 2012

Lot sizing and shipment scheduling are two interrelated decisions made by a manufacturing plant and a third-party logistics distribution center. This paper analyzes a dynamic inbound ordering problem and shipment problem with a freight container cost, in which the order size of multiple products and single container type are simultaneously considered. In the problem, each ordered product placed in a period is immediately shipped by some freight containers in the period, and the total freight cost is proportional to the number of containers employed. It is assumed that the load size of each product is equal and backlogging is not allowed. The objective of this study is to simultaneously determine the lot-sizes and the shipment schedule that minimize the total costs, which consist of production cost, inventory holding cost, and freight cost. Because the problem is NP-hard, we propose three meta-heuristic algorithms: a simulated annealing algorithm, a genetic algorithm, and a new population-based evolutionary meta-heuristic called self-evolution algorithm. The performance of the meta-heuristic algorithms is compared with a local search heuristic proposed by the previous paper in terms of the average deviation from the optimal solution in small size problems and the average deviation from the best one among the replications of the meta-heuristic algorithms in large size problems.

• IE interfaces
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• v.21 no.2
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• pp.161-169
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• 2008

Normally, suppliers have to decide on what, how much, and when to replenish stocks of goods based on a data flow generated by a vendor managed inventory(VMI) system. But information from supply chain is often misleading. It is common for such data to be distorted by a lack of coordination and synchronization across several business entities managing different supply chain operations. This phenomenon is called the 'bullwhip effect(BwE)'. Many researchers, working over many years, have studied the reasons for the BwE. They have proposed various remedies, but this phenomenon persists. Though overlooked in previous research, this paper reveals that the 'lot size' of a supply chain of distribution is indeed the main cause of the BwE. In addition, some problems in the existing methods of measuring the BwE are identified and a revised much improved method of measurement is suggested.

• Journal of the Korea Institute of Building Construction
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• v.4 no.2
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• pp.73-80
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• 2004

The purpose of this study was to look up the proper inventory management system in construction industry. it is important for construction company to improve competitiveness and to reduce construction cost. Lot-sizing techniques were applied to rebar procurement in apartment project. The results of this study were as follows; the method of Groff's marginal cost showed the best performance of other techniques and the method of Norman showed a similar result.

• Journal of Korean Society for Quality Management
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• v.29 no.1
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• pp.113-127
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• 2001

Skip-lot sampling plans for lot-by-lot inspection are more desirable than the continuous sampling plans for units in modern mass production system under the condition of the submitted product is good. Perry(1973a, 1973b) extended the Dodge(1955)′s skip-lot sampling plans to single and two-level skip-lot sampling plans and Parker & Kessler (1981) modified Perry(1973a)′s plans so that a sample of size one is taken from every lot skipped during the skipping mode. In this paper, Perry(1973b)′s two-level skip-lot sampling plans are modified by applying Parker & Kessler′s plan, designated as MTSkSP1, MTSkSP2, MTSkSP3. Operating characteristic(OC) functions, average sample numbers(ASN) and average outgoing qualities(AOQ) for the proposed plans are derived using Markov chain properties and compared each other and Perry′s plans. The proposed plans not only reduce the ASN but also avoid the danger skipping lots entirely when the lots are produced during sudden "out-of-control".

• Journal of the Korean Institute of Rural Architecture
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• v.15 no.1
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• pp.89-96
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• 2013

This study aims to clarify the transformation of urban spatial structure around old castle in cheong-ju city. The urban spatial structure is composed with road system, block division, and lot system with original cadastral map in 1913 and 2011 GIS. Transformation of road system is classified into control of road line, construction and extension of road. Construction of arterial road was divided into Nam-juro and Mang-sunro with 2 blocks and lot system was destoyed. Transformation of block has not been developed except 4 blocks. The 4 blocks were divided into east-west or north-south direction and became 8 blocks. Transformation of lot system is classified into maintained, subdivided, and destroyed lots in shape and size of lots. Maintained lots were found in large lot in size for public office and park. Subdivided lots were mainly represented with the existing main road, an active alleys, and so on. Destroyed lots by road construction and extension were showed in Nam-juro. Although all these transformations are used to enhance urban spatial structure. The old systems have remained around old castle in cheong-ju city.

• Journal of Korean Institute of Industrial Engineers
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• v.12 no.1
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• pp.49-53
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• 1986

A dynamic lot size model is developed for the deteriorating items. The amount of deterioration during a period is assumed to be proportional to the inventory at the end of the period. It is further assumed that deterioration rates can differ among periods. This new model is shown to be equivalent to the general one by simple transformation of some variables. A numerical example is given to illustrate the derived results.