• Journal of Korean Institute of Industrial Engineers
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• v.28 no.4
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• pp.344-350
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• 2002

An alternative to traditional production planning and control systems such as MRP and JIT is the drum-buffer-rope(DBR). Using the DBR system, companies can achieve a large reduction of work-in-process (WIP) and finished-goods inventories (FGI), significant improvement in scheduling performance, and substantial earnings increase. The purpose of this paper is to analyze the effect of the DBR system in a serial production line. Using Markov process, we modeled a DBR system with three stages. For the model developed, we analyze the system characteristics and then present an optimization model for system design. The system performance is also analyzed through sensitivity analysis.

• IE interfaces
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• v.14 no.4
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• pp.348-355
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• 2001

This paper suggests a detailed design of APS(Advanced Planning & Scheduling) system using the DBR (Drum-Buffer-Rope) which is a finite capacity scheduling logic of TOC(Theory of Constraints). Our design is composed of four modules; Network, Buffer, Drum and Subordination. The Network module defines the Product Network which is built from BOM and routings. The Buffer module inserts the Buffers into the Product Network. The Drum module describes detail procedures to create Drum Schedule on the CCR(Capacity Constraint Resource). The Subordination module synchronizes all non-constraints to the constraints by determining the length of Rope. This design documented by ARIS.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2002.05a
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• pp.481-483
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• 2002

Goldratt의 제약이론의 출발점으로 알려져 있는 TOC DBR은, 창안된 이래 꾸준한 연구와 실제 적응을 통해 거의 모든 형태의 제조업체 현장관리에 광범위하게 사용되고 있다. 국내에서는, DBR의 본격적인 적응 사례가 아직 미미한 가운데 있지만, 현재까지 동아시아국가들을 제외한 전세계 산업국가에서 활발한 적용을 보이고 있으며 수많은 적응사례가 발표되고 있다. 본 논문에서는 TOC DBR을 성공적으로 적용한 외국 기업들의 사례를 살펴보므로써, 해당 제조업체의 적용 전 상황과적용 후의 경영개선 내용과 수준을 파악해 보며, 국내 제조업체 적응에 대한 가능성을 가늠해 보고자 한다.

• Journal of Industrial Technology
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• v.31 no.B
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• pp.51-58
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• 2011

Simulation plays a pivotal role in the analysis of complex systems. In this study, a job shop manufacturing system has been analyzed through DBR (Drum-buffer-rope) simulation. Specific attention has been put to examine the rate of due-date achievement. We first derived key factors affecting the system performance. We then developed ARENA simulation program based on DBR of TOC (Theory of Constraints) concepts. Based on the performance measure, factors, and experimental design, we obtained the results. We have drawn meaningful results through examination of the results. The results obtained from this study may provide a good base for practical applications.

• IE interfaces
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• v.15 no.1
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• pp.99-106
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• 2002

A recently developed alternative to traditional production planning and control systems such as material requirement planning(MRP) and just-in-time(JIT) is the drum-buffer-rope(DBR). The DBR now being implemented in growing number of manufacturing organizations enables better scheduling and decision making on the shop floor. In implementing the DBR, however, an information system is usually needed to transmit the signal that runs from the constraint to material release. In this paper we propose a different mechanism to transmit the signal in the case that the demand of product is stable, which uses the well-known Kanban system. To improve the reality, this paper shows and example of the Kanban format, its operation, and calculation of the number of Kanbans.

• 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 the Korea Society for Simulation
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• v.29 no.1
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• pp.57-69
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• 2020

Many researchers have recommended that DBR scheduling would be an efficient method to maintain the balance of their workload among many processes in the general flow shop. However, as product variety has increased in recent years, the process has become more complex and requires the re-entrance of raw materials and work in process. The re-entrant line has known for the complex manufacturing process that raw materials are repeatedly processed on the same machine. This study reviews the applicability of DBR against the re-entrant manufacturing line due to the distinguishing characteristics and the higher complexity caused by multiple visits of a job into the identical process. In order to apply the DBR method to the re-entrant process, the main idea is to reconstruct re-entrant process into a virtual flow process(loop) that has a single bottleneck. This study discusses the following two questions. First, DBR is also superior to traditional scheduling methods against re-entrant manufacturing line. And how we structure and detect the system bottleneck (or sub-bottleneck) through drum-buffer-rope concepts. To answer the above questions, we experimented and analyzed the effects of the applicability of DBR under the general re-entrant process model(TRC, Technology Research Center). As a result, we have identified a balance between loops for cycle time and work in process.

• The Journal of Society for e-Business Studies
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• v.10 no.1
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• pp.61-80
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• 2005

Business Process Management (BPM) System is a software system to support an efficient execution, control and management of business processes. The system automates complex business processes and manages them effectively to raise productivity. Traditional commercial systems mainly focus on automating processes and do not have methods for enhancing process performances and task performer's efficiency. Therefore, there is room for enhancement of task performers' productivities and efficiency of business processes. In this paper, we propose a new method of executing business processes more efficiently in that a whole process is scheduled considering the degree of participants' workload. The method allows managing the largest constraints among constituent resources of the process. This method is based on the DBR (Drum-Buffer-Rope) in TOC (Theory of Constraints) concepts. We first consider the differences between business process models and DBR application models, and then develop the modified drum, buffer and rope. This leads us to develop BP-DBR (Business Process-DBR) that can control the proper size of task performers' work list and arrival rate of process instances. Use of BP-DBR improves the efficiency of the whole process as well as participants' working condition. We then carry out a set of simulation experiments and compare the effectiveness of our approach with that of the scheduling techniques used in existing systems.

• Journal of the Korea Society for Simulation
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• v.24 no.2
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• pp.11-17
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• 2015

Although systems with finite capacities have been the topic of much study, there are as of yet no analytic expressions for (higher) moment and tail probability of stationary waiting times in systems with even constant processing times. The normal queueing theory cannot properly handle such systems due to the difficulties caused by finite capacity. In this study, for a DBR (Drum-Buffer-Rope) line production system with constant processing times, we introduce analytic expressions by using previous results obtained using a max-plus algebraic approach.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.04a
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• pp.754-757
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• 2000

인터넷을 이용한 사이버 거래가 빠른 속도로 증가함으로써 기업에게 있어 인터넷 쇼핑몰 구축은 더 이상 선택사항이 아닌 필수 사항이 되었다. 하지만 현재 사이버 거래 수준은 전통적 상거래 수준에 못 미칠뿐더러 거래 항목에 있어서도 매우 제한적인 것이 사실이다. 앞으로 사이버 거래는 계속적으로 증가하리라 전망되지만 제품의 특성 혹은 고객의 기호에 따라 전통적 상거래도 그 영역을 차지하며 함께 양립하여 발전할 것이다. 이에 본 연구에서는 기존의 상거래 시스템에 사이버 거래기능을 추가하는 모델을 제시한다. 먼저 지리적으로 멀리 떨어져 있는 유통망의 정보화를 위하여 인터넷 기술을 이용하고 공급체인(Supply Chain) 전체에 걸친 동기화를 위해 TOC(Theory of Constraint)의 DBR(Drum-Buffer-Rope) 스케줄링을 응용한다. 모든 생산 및 유통의 흐름 속도가 최종 분배 센타에 접수되는 고객의 요구에 따라 이루어지게 함으로써 공급체인 전체에 걸친 동기화를 이룰 수 있고 지속적인 버퍼 관리를 통하여서 재고의 절감은 물론 미출고의 발생도 최소화할 수 있다. 만약 분배 센타에 재고부족 현상이 일어날 경우에는 공급체인 상의 능력제약자원(Capacity Constraint Resource . CCR)을 찾아 개선 활동을 수행하며 공급체인의 흐름 속도를 능력제약자원에 맞추어 조절한다. 분배 센타에서 대리점 혹은 사이버 고객으로의 배송은 부분적 분할납품 Partial Transshipment : PT) 전략을 적용한다. 즉 각 분배 센타가 관리하는 수요지 중 인접한 지역을 부분적 분할납품 전략 적용 수요지로 선택하고 사이버 거래를 통해 생성된 물류가 부분적 분할납품 전략 적용 수요지에 분배되게 함으로써 각 분배 센타의 재고 완충역할을 수행하게 한다. 이에 따라 안전 재고 및 역 배송을 최소화 할 수 있을 뿐 아니라 미 출고로 인한 손실을 최소화하며 고객의 서비스를 일정하게 유지시킬 수 있을 것으로 기대된다.