• Industrial Engineering and Management Systems
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• 제4권2호
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• pp.158-164
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• 2005

Kusukawa and Ohta presented the $CS_{CQ-r}$ chart to monitor the process defect $rate{\lambda}$ in high-yield processes that is derived from the count of defects. The $CS_{CQ-r}$ chart is more sensitive to $monitor{\lambda}$ than the CQ (Cumulative Quantity) chart proposed by Chan et al.. As a more superior chart in high-yield processes, we propose a Synthetic chart that is the integration of the CQ_-r chart and the $CS_{CQ-r}$chart. The quality characteristic of both charts is the number of units y required to observe r $({\geq}2)$ defects. It is assumed that this quantity is an Erlang random variable from the property that the quality characteristic of the CQ chart follows the exponential distribution. In use of the proposed Synthetic chart, the process is initially judged as either in-control or out-of-control by using the $CS_{CQ-r}$chart. If the process was not judged as in-control by the $CS_{CQ-r}$chart, the process is successively judged by using the $CQ_{-r}$chart to confirm the judgment of the $CS_{CQ-r}$chart. Through comparisons of ARL (Average Run Length), the proposed Synthetic chart is more superior to monitor the process defect rate in high-yield processes to the stand-alone $CS_{CQ-r}$ chart.

• 산업공학
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• 제18권3호
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• pp.221-233
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• 2005

e-Manufacturing can be referred to as a system methodology enabling the integration of manufacturing operations and IT technologies to achieve objectives of an enterprise. It is recently regarded as a powerful solution to survive in a chaotic marketplace. While conducting an e-Manufacturing project, we first needed to capture collaborative processes conducted by multiple participants in order to define functions of a system supporting them. However, pervasive process modeling techniques including IDEF3, Petri nets, and UML are not sufficient for modeling collaborative processes. Therefore, we first briefly investigate several process modeling methods including aforementioned modeling methods and ARIS focusing on the collaboration point of view. Then, we propose a new modeling method referred to as Collaborative Process Modeling (CPM) to clearly describe collaborative processes. Also, we develop and illustrate a rule for transforming collaborative process models into Marked Graph models to use the analysis power of the Petri nets. Using CPM empowers us to develop collaborative process models with simple notations, understand and facilitate the realization of the collaboration, and verify models before rushing into the development.

• Korea-Australia Rheology Journal
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• 제19권3호
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• pp.171-176
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• 2007

LCD-BLU (Liquid Crystal Display-Back Light Unit) of medium size is usually manufactured by forming numerous dots with $50{\sim}300\;{\mu}m$ in diameter by etching process and V-grove shape with $50\;{\mu}m$ in height by mechanical cutting process. However, the surface of the etched dots is very rough due to the characteristics of the etching process and V-cutting needs rather high cost. Instead of existing optical pattern made by etching and mechanical cutting, 3-dimensional continuous micro-lens of $200\;{\mu}m$ in diameter was applied in the present study. The continuous micro-lens pattern fabricated by modified LIGA with thermal reflow process was tested to this new optical design of LGP. The manufacturing process using LIGA-reflow is made up of three stages as follows: (i) the stage of lithography, (ii) the stage of thermal reflow process and (iii) the stage of electroplating. The continuous micro-lens patterned LGP was fabricated with injection molding and its test results showed the possibility of commercial use in the future.

• 한국물환경학회지
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• 제25권4호
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• pp.530-538
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• 2009

The Oxic-Settling-Anaerobic (OSA) treatment process, a modified Conventional Activated Sludge (CAS) process, was developed for the purpose of sludge reduction. The insertion of a sludge holding tank into a sludge return line, an anaerobic reactor, forming an OSA process, may provide a cost-effective way of reducing excess sludge production during a process. The OSA process was evaluated for its sludge reduction ability by kinetic parameter and mass balance, with an observed excess sludge reduction of 63.5%, as $P_{X.VSS}$, compared with the conventional activated sludge process.

• 한국분말재료학회지
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• 제27권3호
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• pp.256-267
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• 2020

Metal additive manufacturing (AM) technologies are classified into two groups according to the consolidation mechanisms and densification degrees of the as-built parts. Densified parts are obtained via a single-step process such as powder bed fusion, directed energy deposition, and sheet lamination AM technologies. Conversely, green bodies are consolidated with the aid of binder phases in multi-step processes such as binder jetting and material extrusion AM. Green-body part shapes are sustained by binder phases, which are removed for the debinding process. Chemical and/or thermal debinding processes are usually devised to enhance debinding kinetics. The pathways to final densification of the green parts are sintering and/or molten metal infiltration. With respect to innovation types, the multi-step metal AM process allows conventional powder metallurgy manufacturing to be innovated continuously. Eliminating cost/time-consuming molds, enlarged 3D design freedom, and wide material selectivity create opportunities for the industrial adoption of multi-step AM technologies. In addition, knowledge of powders and powder metallurgy fuel advances of multi-step AM technologies. In the present study, multi-step AM technologies are briefly introduced from the viewpoint of the entire manufacturing lifecycle.

• 품질경영학회지
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• 제37권3호
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• pp.39-53
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• 2009

This paper suggests a new process structuring method, which we call process modularization, for decomposing and grouping activities in a process. Above all, we propose the concept of a module that is a group of activities positioned on the same flow before and after control constructs. Since activities in a module are relatively strongly interrelated with one another, it is important to take into consideration of these together. A design structure matrix (DSM) is used to structure the process because it has a lot of advantages in process modeling and analysis. We developed two algorithms: the restricted topological sorting (RTS) algorithm for ordering activities and the module finding (MF) algorithm for detecting modules in a process, which utilize the DSM. The suggested approach enables a firm's manager to design and analyze the process effectively. We also developed a supporting tool to accelerate the progress of process modularization. The supporting tool aids the process manager in finding the module and understanding the process structure easily. An illustrative example is addressed to show operations of the suggested approach.

• 산업기술연구
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• 제28권A호
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• pp.149-153
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• 2008

$C_p$ and other process capability indices are used extensively in industry, However, They are inadequate and widely misused. In a practical application, process average ${\mu}$ is almost always drifted by various assignable causes in process. And control charts will not detect these shifts in process average. In this study, incorporating these undetected shifts, a new capability analysis method is introduced.

• 산업경영시스템학회지
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• 제15권26호
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• pp.137-150
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• 1992

As a part of quality control activities for developing competitive products, the significant method of process quality assurance for solving initial production quality problems is just quality control process chart(QC process chart). However, the QC process chart which is used for domestic enterprises at present had obscured in basement and not itemized by industry and formally used. So. in this study, the improved QC process charts which classified by industry we suggested so that each enterprise may utilize them according to the each enterprise characteristics.

• 대한산업공학회지
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• 제11권2호
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• pp.189-194
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• 1985

Process Capability Index is defined as a ratio between predetermined tolerance and natural tolerance of existent process ($6{\sigma}$). And it is widely used as a performance measure for quality control activities, and a criterion for process classification. This paper developed a unity-fixed process capability table for convenience to calculate process capability and showed how to use it.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 1998년도 추계학술대회 및 정기총회
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• pp.199-203
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• 1998

Process planning and scheduling are traditionally regarded as separate tasks performed sequentially. But if two tasks are performed concurrently, greater performance can be achieved. In this study, we propose new approach to integration of process planning and scheduling. We propose new process planning combinations selection method using simulation based genetic algorithms. Computational experiments show that proposed method yield better performance when compared with existing methods.