• Journal of Korean Society for Quality Management
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• v.32 no.2
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• pp.154-167
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• 2004

The TOC/DBR and Six Sigma are the most attention-getting concepts for managing manufacturing companies in Korea. Using the ideas and methods of the TOC/DBR, companies can achieve a large reduction of work-in-process and finished-good inventories, significant improvement in scheduling performance, and substantial earnings increase. The Six Sigma approach derives the overall process of selecting the right projects based on their potential to improve performance metrics and selecting/training the right people to get the business results. These two concepts have different backgrounds and different viewpoints for production systems. So, if the two concepts collaborate each other, the synergy effects to innovate production systems can be expected. This paper proposes a new approach to implement the TOC/DBR concepts in production systems. This approach uses some concepts of Six Sigma which stresses educations, project approaches (step by step procedure using a Roadmap), and improvement philosophy.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.39 no.1
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• pp.130-139
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• 2016

The purpose of this paper is to analyze the problems and the sources of defective products and draw improvement plans in a small plastic boat manufacturing process using TOC (Theory Of Constraints) and statistical analysis. TOC is a methodology to present a scheme for optimization of production process by finding the CCR (Capacity Constraints Resource) in the organization or the all production process through the concentration improvement activity. In this paper, we found and reformed constraints and bottlenecks in plastic boat manufacturing process in the target company for less defect ratio and production cost by applying DBR (Drum, Buffer, Rope) scheduling. And we set the threshold values for the critical process variables using statistical analysis. The result can be summarized as follows. First, CCRs in inventory control, material mix, and oven setting were found and solutions were suggested by applying DBR method. Second, the logical thinking process was utilized to find core conflict factors and draw solutions. Third, to specify the solution plan, experiment data were statistically analyzed. Data were collected from the daily journal addressing the details of 96 products such as temperature, humidity, duration and temperature of heating process, rotation speed, duration time of cooling, and the temperature of removal process. Basic statistics and logistic regression analysis were conducted with the defection as the dependent variable. Finally, critical values for major processes were proposed based on the analysis. This paper has a practical importance in contribution to the quality level of the target company through theoretical approach, TOC, and statistical analysis. However, limited number of data might depreciate the significance of the analysis and therefore it will be interesting further research direction to specify the significant manufacturing conditions across different products and processes.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.4
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• pp.22-33
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• 2018

Recently domestic manufacturing companies have been experiencing worsening profitability and stunted growth due to the long-term economic recession and the rapid rise of developing countries such as China and Southeast Asia. These difficulties force many companies to concentrate their core competencies on new value creation and innovation in order to gain momentum for new growth. Enterprise Resource Planning (ERP) has been considered as one of viable solutions. Among the various modules in ERP, shop floor control function in the production management module is rather limited. In order to overcome this problem, Manufacturing Execution System (MES) has been used as a subsystem which has a strong information gathering power and flexibility. Both systems interact closely with each other. In particular, ERP requires fast, accurate shop floor information at MES. This paper describes how to synchronize relevant information between ERP and MES with theory of constraints (TOC). The processing time information transmitted from the MES workplace is received at the ERP workplace. In the process, the received processing time is causing information distortion in ERP, when the information gathering standard of MES is different from the ERP information interpretation standard. The Drum-Buffer-Rope theory of TOC was applied to resolve this problem, therefore, information synchronization between both systems was made. As a precondition, the standard time of the upper ERP system was rearranged according to the capacity constraints resource. As a result, standard time restructuring has affected changes in labor costs. Standard labor costs have come close to actual ones, and information synchronization of MES transmission data has improved the reliability of standard product costs, such that it enabled various company-wide restructuring actions to be much more effective.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.33 no.2
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• pp.72-80
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• 2010

Recently, paradox management is a new paradigm to solve the management dilemmas. This is a new perspective and a creative way of thinking to draw the synergic effect by pursuing simultaneously the conflicting elements. As one method for the paradox management, this paper proposes a process of combining the TOC (Theory Of Constraints) and TRIZ (Russian Theory of Inventive Problem Solving) and applies to a dilemma case in business environments.

• Journal of Korean Institute of Industrial Engineers
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• v.43 no.1
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• pp.12-18
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• 2017

This study presents a plant concept design for a smart factory which is mainly targeted to machine airplane parts. The plant layout is based on the TOC-DBR approach together with autonomous distributed factory control considered, while discrete event simulation is also performed in order to validate its layout. The resulting layout and its procedure turn out to be quite a useful guideline in realizing those smart factories especially for machining-oriented manufacturing industries.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.37 no.4
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• pp.63-71
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• 2014

As power consumption increases, more power utilities are required to satisfy the demand and consequently results in tremendous cost to build the utilities. Another issue in construction of power utilities to meet the peak demand is an inefficiency caused by surplus power during non-peak time. Therefore, most power company considers power demand management with time-based electricity rate policy which applies different rate over time. This paper considers an optimal machine operation problem under the time-based electricity rates. In TOC (Theory of Constraints), the production capacities of all machines are limited to one of the bottleneck machine to minimize the WIP (work in process). In the situation, other machines except the bottleneck are able to stop their operations without any throughput loss of the whole manufacturing line for saving power utility cost. To consider this problem three integer programming models are introduced. The three models include (1) line shutdown, (2) block shutdown, and (3) individual machine shutdown. We demonstrate the effectiveness of the proposed IP models through diverse experiments, by comparing with a TOC-based machine operation planning considered as a current model.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.37 no.4
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• pp.162-167
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• 2014

This study is to solve the public education's dilemma between the standardized education to maximize learning efficiency and the personalized education to maximize learning effectiveness, using the paradox management process. The process is based on combining the TOC (Theory Of Constraints) and TRIZ (Russian Theory of Inventive Problem Solving), which is a creative way of thinking to draw the synergic effect by pursuing simultaneously the conflicting elements. Through this research, a new concept of learning method can be suggested on a public course. Further research should be performed to develop a learning guideline based on the students' empirical study results.

• Korea Journal of Hospital Management
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• v.16 no.1
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• pp.77-100
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• 2011

The purpose of this study is to the improvement of general hospital outpatients waiting time using Theory Of Constraints(TOC) methodology and to the development of a Reception Desk in general hospital. This study is to provide decision-making guidelines for hospital managers and to provide feedback for the efficiency of job process. The target people of the study are outpatients and Cashiers on Chungnam national university hospital in Daejeon. The methods of study are summarized as follows. First, The team managers from a Reception Desk group were appointed. This team managers have the adjustment authority to the Outpatients schedule of doctor and Cashier members. Second, The consolidation of the general Reception desk and special inspection the Reception Desk. A movement line and waiting time of patients were simple and fast to accept. As a result of study, it shows that the TOC is the method for a job process and waiting time improvement, patients' satisfaction increase and we need an objective measurement indexes in the medical treatment industry.

• The Journal of Information Systems
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• v.15 no.1
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• pp.169-189
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• 2006

Recently, many companies are trying to survive in a competitive business environment and they employ various kinds of information systems. Business Process Management (BPM) system is a software system that integrated enterprise information systems based on processes, which is considered an essential element for managing inner and outer processes. Though the BPM system has been applied to major processes only so far, companies begin to extends target processes applied into enterprise wide. In such settings, not only exact but also efficient management of processes is required. The efficiency of BPM has two perspectives: one is the performance of users that handle assigned tasks, and the other is the performance of the Business Process (BP) engine that carries out execution of processes. In this paper, in order to deal with the seconde perspective, we develop Drum, Buffer, and Rope (DBR) method, which have been considered innovative Theory of Constraint (TOC) method in manufacturing domain, for efficient management of processes. A new method, BP-DBR, has been developed, and we show that it is effective for business processes. The effectiveness of the method has been proved in terms of efficiency measures such as average process completion time and average number of completed processes, through a series of simulations on real banking processes.

• Journal of the Korea Society for Simulation
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• v.21 no.3
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• pp.25-33
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• 2012

Ptak & Smith published ORLICKY'S Material Requirement Planning Third Edition in 2011 to correspond the rapidly changed market demand by improving the original MRP based on Theory of Constraints(TOC) replenishment inventory management. This study is to develop the simulation model to decide the proper target inventory level for TOC replenishment inventory management using system dynamics Vensim software. This study shows that the proper target replenishment level is how much significant to manage the inventory by the random sample data simulation. This simulation model will be extended to compare the results of the TOC replenishment inventory management planning with the results of the old MRP planning by the enterprise actual inventory data.