• Journal of the Korea Society for Simulation
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• v.20 no.2
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• pp.19-27
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• 2011

This study investigates impact of smoothed replenishment ordering policy on the performance measures such as lead time, order fulfillment ratio, and inventory cost. We consider a two-echelon supply chain: a single retailer orders using smoothed order up to replenishment policy and a manufacturer produces the retailer's orders on a make to order basis. Simulation result confirms that lead time from the manufacturer can be reduced by smoothed ordering policy as expected. However, smoothing orders may deteriorate the customer order fulfillment ratio and inventory cost in a retailer. We also observe that variance of manufacturing time contributes more than mean of manufacturing time to both order fulfillment ratio and inventory cost. Therefore, variability of upstream manufacturing time should be minimized.

• Design & Manufacturing
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• v.18 no.2
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• pp.51-56
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• 2024

In this study, a tool was developed for analyzing production lead time in turning operations. It is expected to help to reduce machining time and to identify, for example, tool change intervals. The tool was developed using Visual Basic.Net and features a user-friendly graphical user interface (GUI) that allows users to easily input cutting conditions and calculate the usage time and feeding distance for each cutting tool based on a G-code program. Object-oriented programming techniques were also used to encapsulate and classify complex logic, thereby efficiently organizing and managing the functions and data structures of this analysis tool. The analysis tool provides various outputs. It calculates the use time of each detailed process of the turning operation, the use time of each tool, the use time of each type of feeding, and also generates the data needed for cutting time analysis, which can be visualized in charts. The analysis tool developed in this study is expected to significantly contribute to improving the efficiency of manufacturing processes and increasing productivity, particularly, in the manufacturing of components requiring massive material removal, such as aircraft parts.

• IE interfaces
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• v.12 no.3
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• pp.424-436
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• 1999

Due to environmental change in market, delivery satisfaction to customers and reduction of lead time are critical in the make-to-order manufacturing system. A case of production scheduling process restructuring is studied for one company which employed ERP system. Based on the standard module ERP package provided, they modified and added several functions for their specific processes, and implemented it in production scheduling. The ratio of delivery satisfaction has been improved from 51.1% to 60.8%, and manufacturing lead time has been reduced from 43 days to 30 days in average during 10 months. Moreover, they achieved several side effects such as real time production scheduling and workload analysis, information sharing over all departments, and improving flexibility in receiving orders.

• IE interfaces
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• v.21 no.4
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• pp.418-434
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• 2008

This paper studied issues in decision making on the production control policy of a cathode plate manufacturing process in zinc refining plant. The present production system has a long lead time from raw materials (aluminum plate) to products (cathode plate) due to many WIP inventories. Because WIP inventories are stocked at each process and moved from one place to another frequently, they are the main cause of inefficiency in the process. In this paper, to solve this problem, several production control policies have been identified and studied. Several simulation models are used to compare the performances of these production control policies. The output lead time and WIP (Work In Process) of real production system are compared with those of simulation models. PUSH, CONWIP, DBR, KANBAN and CONWIP-DBR models have been used to simulate and review the optimized production control policy that achieves the target output quantities with decreased lead time and WIP. The simulation results of each production control policy show that CONWIP and CONWIP-DBR models are the good production control policy under the present production system. Especially in present production system, CONWIP with one parameter is easier control policy than CONWIP-DBR with two parameters. Therefore CONWIP has been selected as the best optimum production control policy. With CONWIP, lead time has been reduced by 97% (from 6,653 to 187 minute) and WIP has been reduced from 1,488 to 53, compared to the present system.

• Journal of the Korea Society of Computer and Information
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• v.25 no.11
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• pp.115-122
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• 2020

In this paper, we propose an MES system based on real-time process capability management and how to manage the manufacturing process using the system. The current MES system presents a KPI report that makes it easy to recognize the manufacturing site, but has not been able to derive an improvement method to improve the actual manufacturing site KPI. In other words, it is difficult to extract the cause of the increase in defective rate, decrease in yield, and increase in production lead-time, and to draw an improvement plan and apply it to the manufacturing site. The purpose of the MES system based on real-time process capability management proposed in this paper is to establish an manufacturing operation management system that overcomes the limitations of the existing MES by managing the distribution of major factors of the equipment that determines the process capability. In addition, by presenting a speed improvement method for real-time large-capacity data processing, it is intended to be applied so that the system can operate well.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.10a
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• pp.355-360
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• 2000

Recently, to be satisfied the consumer's demand the life cycle and the lead time of product is to be shorted. So it is important to reduce the time and cost in manufacturing prototypal mold. These days, in order to reduce the lead time and cost high speed machining is highlighted. In the paper, using the high speed machining and aluminum-7075, the fundamental experiment is implemented in the change of cutting force, machining time, surface characteristic according to the tool path. And then the prototypal mold of the automatic knob is machined.

• 연구논문집
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• s.27
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• pp.167-174
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• 1997

Point of Production/Manufacturing Execution Systems are an essential component of operations in today's competitive business environments, which require greater production efficiency and effectiveness. POP/MES focuses on the valuing-adding processes, helping to reduce manufacturing cycle time, improve product quality, reduce WIP, reduce or eliminate paperwork between shifts, reduce lead time and empowering plant operations staff. In this paper, we implement POP/MES to manage real-time plant floor data which is gathered by I/O server into database management system. I/O server is a software allows data exchange between factory real-time database and several hardware devices such as PLC, DCS, robot and sensor through ethernet TCP/IP protocol.

• The KIPS Transactions:PartD
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• v.10D no.1
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• pp.161-166
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• 2003

Information lead time is defined as the time spent by processing orders from some buyers, whereas order lead time is defined as producing and supplying the products. The information lead time significantly serve to magnify the increase in variability due to demand forecasting. This paper models a decentralized supply chain composed of cascade type which has four type phases (or divisions) such as retailer, wholesaler, distributor, and factory. Each phases is managed by different centers individually with their own local inventory information. We investigate whether each phase's Information lead time affects companies networked a value chain. In particular, on several experiments performed with a programmed simulation (like a MIT beer game), we study the following question ; Can information lead times do better than material lead times in cost-benefit perspective\ulcorner Can more much Information lead times in downstream reasonably do worser than in upstream when playing the simulation\ulcorner In the conclusion, we show the importance of information lead time on a SC and, besides, guarantee that improvement of information lead time in upstream do more effective than one in downstream in cost-benefit perspective.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.11a
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• pp.342-345
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• 2003

Due to the rapid development of manufacturing and information technology, traditional supply chain scheme has been changed dramatically Most companies have been forced to relocate or redesign their logistics network in different countries. A supply chain partnership is a relationship formed between two independent members in supply chain through information sharing to achieve specific objectives and benefits in terms of reductions in total costs and inventories. This study illustrates the benefits of supply chain partnerships based on information sharing and lead-time patterns. We consider three level of information sharing: (1) immediate order information; (2) demand information; (3) inventory information. Given a fixed total lead-time, how lead-time distribution will affect the bullwhip effect and inventory cost under information sharing strategies. The results can help improving supply chain performance and selecting suitable direction for the re-configuration of supply chain network.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.10a
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• pp.217-218
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• 2009