• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.2
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• pp.24-35
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• 2021

Due to increasing awareness on the treatment of end-of-use/life products, disassembly has been a fast-growing research area of interest for many researchers over recent decades. This paper introduces a novel lot-sizing problem that has not been studied in the literature, which is the service-parts lot-sizing with disassembly option. The disassembly option implies that the demands of service parts can be fulfilled by newly manufactured parts, but also by disassembled parts. The disassembled parts are the ones recovered after the disassembly of end-of-use/life products. The objective of the considered problem is to maximize the total profit, i.e., the revenue of selling the service parts minus the total cost of the fixed setup, production, disassembly, inventory holding, and disposal over a planning horizon. This paper proves that the single-period version of the considered problem is NP-hard and suggests a heuristic by combining a simulated annealing algorithm and a linear-programming relaxation. Computational experiment results show that the heuristic generates near-optimal solutions within reasonable computation time, which implies that the heuristic is a viable optimization tool for the service parts inventory management. In addition, sensitivity analyses indicate that deciding an appropriate price of disassembled parts and an appropriate collection amount of EOLs are very important for sustainable service parts systems.

• Korean Business Review
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• v.1
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• pp.249-271
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• 1987

Applicability of control theories to the efficient operation of accounting system is studied in this paper. Since managerial accounting has been developed along the progrees of control theory, management control theories are essential to explain important attributes of diverse accounting system. Basic concept of control is studied in depth and control systems are classified on the base of their special characteristics. And then the applicability of those control methods to accounting systems are discussed based on behavioral as well as management science approach. In the management science approach, accounting control models of production management, inventory management and R&D are designed with its unique quantitative characteristics. It, however, is very difficult to implement quantified control standards on the behavioral management side. Since most of variables considered on behavioral approach are non-quantitative, only discussion of the theoratical definition has been a main issue on previous studies. In this paper, practicability of the behavioral approach to the accounting control system is studied analyzing state variables and behavior variables of the control system. Theoratical base of the discussion are provided from control theories developed in organization theory and Economics. Basic objective of accounting control practice is to control qualitative human behavior represented by quantified figures while quantitative methods are prevailing over general accounting practice. Therefore, this paper tried to develope and integrate accounting control systems applicable to the behavioral management area as well as management science control side.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.34 no.2
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• pp.76-84
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• 2011

To meet the needs of customer, manufacturing companies are diversifying product making methods. In order to adapt to changes, companies are trying to find a new manufacturing system. In this research, MTS (Make to Stock) and MTO (Make to Order) production methods are simulated using ARENA and the results are compared and analyzed to find a better system. As a result, by combining the advantages of MTS and MTO system, a hybrid production system is developed. The hybrid model is analyzed to verify that it is better than the existing two models, which is MTS and MTO model. The statistic results of output analyzer show that a new system helped to increase production rate and decrease work in process inventory. The hybrid model proved that it contains the merits of MTO production method and MTS production method.

• IE interfaces
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• v.13 no.3
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• pp.358-377
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• 2000

A supply chain is a network of facilities and distribution options that performs the functions of procurement of materials, transformation of these materials into intermediate and finished products, and the distribution of these finished products to customers. SCM(Supp1y Chain Management), by definition, encompasses all activities associated with moving goods, from the raw materials stage through to the end user. It includes source and procurement, production scheduling, order processing, inventory management, transportation, warehousing, and customer service. Importantly, it encompasses the information systems used to monitor these activities. In this paper, the present situation and problems of marketing process in Korean agricultural environments were reviewed through a systematic methodology, and then we proposed a new business process for solving these problems by appling a supply chain management. We expect this supply chain management system applied to agricultural marketing process can improve significantly the rationality and transparency of Korean agricultural marketing structure.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.17 no.31
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• pp.99-114
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• 1994

The introduction of new equipments to strengthen the competitiveness of enterprises is one of pretty important factors. Enterprises introducing new equipments strengthen competitiveness through productivity increasing, high quality maintenance, inventory reduction, improved design and production interface, simple scheduling process, low scrap rate, rework reduction, etc. Managers will work out the best equipment-replacing strategy through the appropriate combination of potential cost attributes and qualitative attributes difficult to quantify in accordance with the business purpose. This study is to present a method to select an equipment-replacing alternative through the decision-making model of Analytic Hierarchy Process in consideration of the differences of cost flow of the alternatives, taking into consideration tangible attributes and strategic intangible attributes.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.23 no.59
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• pp.21-36
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• 2000

The drum-buffer-rope(DBR) system is a finite scheduling mechanism that balances the flow of the production system. DBR controls the flow of materials through the plant in order to produce products in accordance with market demand, with a minimum of manufacturing lead time, inventory, and operating expenses. This paper integrates the best of MRP push system and JIT pull system with DBR system, efficiently adapts these logics to capacity constraint resources, and contributes to the evolution of synchronous manufacturing. The purpose of this paper is, thus, threefold. The first objective is to identify the frame of theory of constraints(TOC) and the logic of DBR scheduling. The second objective is to formulate the DBR constraint scheduling problems(DBRCSP) in a job shop environments. Finally, the paper is to suggest the solution procedure of DBRCSP for embedding TOC into MRP/JIT along with an numerical expression. In addition, illustrative numerical example is given.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.22 no.51
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• pp.29-40
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• 1999

The distribution center location and routing problem involves interdependent decisions among facility, transportation, and inventory decisions. The design of distribution system affects the customers' purchase decision by sets the level of customer service to be offered. Thus the lower product availability may cause a loss of demand as falls off the customers' purchase intention, and this is related to the firm's profit reduction. This study considers the product availability of the distribution centers as the measure of the demand level change of the demand points, and represents relation between customer service and demand level with linear demand function. And this study represents the distribution center location and routing to demand point in order to maximize the total profit that considers the products' sales revenue by customer service, the production cost and the distribution system related costs.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.22 no.50
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• pp.209-219
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• 1999

This paper presents an efficient operational technique of material feeding process, trainning for multi-operations, machine conditions, and role of foreman and material-supplying man, for constructing the flexible assembly cells in the domestic electronic industries. And an practical method for computing the number of economical cells is also presented by the cost-effective model that compares the additional assembly machine requirement with the four reductive effects including WIP/finished goods inventory, the troubles in the assembly line, the opportunity loss for small order quantity, and amounts of production management due to the introduction of cell line. An case study is introduced in for a domestic electronic assembly line at the end.

• IE interfaces
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• v.13 no.3
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• pp.378-387
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• 2000

As the globalization of manufacturing companies continues, the scope of dependence between these companies and distributors, and other suppliers are growing very rapidly since no one company manufactures or distributes the whole product by themselves. And, the need to increase the efficiency of the whole supply chain is increasing. This paper deals with a multi-plant lot-sizing problem(MPLSP) which happens in a decentralized manufacturing system of a supply chain. In this study, we assume that the whole supply chain is driven by a single source of independent demand and many levels of dependent demands among manufacturing systems in the supply chain. We consider setup cost, transportation cost and time, and inventory holding cost as a decision factor in the MPLSP. The MPLSP is decomposed into two sub-problems: a planning problem of the whole supply chain and a lot-sizing problem of each manufacturing system. The supply chain planning problem becomes a pure linear programming problem and a Generalized Goal Decomposition method is used to solve the problem. Its result is used as a goal of the lot-sizing problem. The lot-sizing problem is solved using the CPLEX package, and then the coefficients of the planning problem are updated reflecting the lot-sizing solution. This procedure is repeated until termination criteria are met. The whole solution process is similar to Lagrangian relaxation method in the sense that the solutions are approaching the optimum in a recursive manner. Through experiments, the proposed closed-loop hierarchical planning and traditional hierarchical planning are compared to optimal solution, and it is shown that the proposed method is a very viable alternative for solving production planning problems of decentralized manufacturing systems and in other areas.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.1
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• pp.79-86
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• 2017

This research focused on deciding optimal manufacturing WIP (Work-In-Process) limit for a small production system. Reducing WIP leads to stable capacity, better manufacturing flow and decrease inventory. WIP is the one of the important issue, since it can affect manufacturing area, like productivity and line efficiency and bottlenecks in manufacturing process. Several approaches implemented in this research. First, two strategies applied to decide WIP limit. One is roulette wheel selection and the other one is elite strategy. Second, for each strategy, JIT (Just In Time), CONWIP (Constant WIP), Gated Max WIP System and CWIPL (Critical WIP Loops) system applied to find a best material flow mechanism. Therefore, pull control system is preferred to control production line efficiently. In the production line, the WIP limit has been decided based on mathematical models or expert's decision. However, due to the complexity of the process or increase of the variables, it is difficult to obtain optimal WIP limit. To obtain an optimal WIP limit, GA applied in each material control system. When evaluating the performance of the result, fitness function is used by reflecting WIP parameter. Elite strategy showed better performance than roulette wheel selection when evaluating fitness value. Elite strategy reach to the optimal WIP limit faster than roulette wheel selection and generation time is short. For this reason, this study proposes a fast and reliable method for determining the WIP level by applying genetic algorithm to pull system based production process. This research showed that this method could be applied to a more complex production system.