• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.612-615
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• 2002

The objective of this study is to develop an integrated process planning system which can flexibly cope with the status changes in a shop floor by utilizing the concept of Non-Linear and Closed-Loop Process Planning(NCPP). In this paper, Genetic Algorithm(GA) is employed in order to quickly generate feasible setup sequences for minimizing the makespan and tardiness under an NCPP. The genetic algorithm developed in this study for getting the machine load utilizes differentiated mutation rate and method in order to increase the chance to avoid a local optimum and to reach a global optimum. Also, it adopts a double gene structure for the sake of convenient modeling of the shop floor. The last step in this system is a simulation process which selects a proper process plan among alternative process plans.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1821-1824
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• 2008

A novel in-mold packaging process has been developed to manufacture devices with closed channels. In this unified process, fabrication of open channels and forming the rigid cover on top of them are sequentially integrated in the same mold. The entire process is comprised of two phases. In the first phase, the open channels are fabricated under an exquisitely controlled temperature and pressure using the conventional micro injection molding technology. In the second phase, the closed channels are fabricated by conducting the injection molding process using the molded structure with the open channels as a mold insert. As a result, the in-mold technology can eliminate the bonding processes such as heating, ultrasonic or chemical processes for cohesion between the channel and the cover, which have been required in conventional methods.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10b
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• pp.1557-1563
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• 1991

Vendors and consultants struggle to draw attention to their proven experience in discrete CIM in order to convince process manufacturers to adopt CIM technology. The analogy works very well at the periphery where an invoice is an invoice, but disintegrates at the core where modeling of the manufacturing "process" is required. Until recently, it has not been possible to completely and rigorously model entire process plants in real-time, and this missing core element has been called the "CIM GAP" With the recent introduction of the concurrent resolution $^{sm}$ kernel, the CIM GAP now is being closed in the process industries.ntroduction of the concurrent resolution $^{sm}$ kernel, the CIM GAP now is being closed in the process industries.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.571-574
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• 2004

Symmetric closed-cell type barrier ribs of PDP were formed by capillary molding process using molds prepared by inclined UV lithography process. The effects of inclining angle of barrier ribs on the sintering shrinkage and luminance of panel were examined. The results indicate that the barrier ribs of inclined morphology affect the sintering shrinkage and luminance efficiency significantly.

• Journal of Electrical Engineering and Technology
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• v.12 no.6
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• pp.2208-2218
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• 2017

To resolve overload in a distribution system, a distribution system operator (DSO) often performs a load transfer using normally open tie points and switches in the distribution line. During this process, the distribution system is momentarily operated in closed-loop operation. A closed-loop current in the distribution system can cause a power failure due to excess breaking current in the circuit breakers and reclosers. Therefore, it is necessary to calculate the closed-loop current exactly. However, if there are a large number of distributed generation (DG) systems in the distribution system, such as energy storage systems (ESS), they might obstruct the closed-loop operation based on bidirectional power flow. For quick and precise operation of a closed-loop system, the ESS has to regulate the power generation while satisfying closed-loop operation in the worst cases. We propose a strategy for balanced power regulation of an ESS. Simulations were carried out using PSCAD/EMTDC, and the results were compared with calculation results.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.27-33
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• 2003

In closed-die forging process, blocker has been used to fill and distribute metal well in finisher die. Generally, the blocker shape was determined by an expert with many experiences. However, the manual blocker design process takes much time and efforts, so various automatic methods for the blocker design process have been suggested for the last three decades. The method with filtering in FFT (Fast Fourier Transform) for the blocker design provides general solution than other methods. But, due to the properties of FFT in time-frequency domain, this method has some drawbacks such as long calculation time, difficulty of local control and additional boundary process after filtering. In this study, DWT (Discrete Wavelet Transform), which is more flexible and is more wildly used than FFT, is applied to the blocker design. The method with filtering in DWT is very proper to design blocker in both 2-D and 3-D shapes. To verify the efficiency of this method, blockers of some models are designed and the results show that blocker design with DWT is effective fer the blocker designs

• Transactions of Materials Processing
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• v.12 no.4
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• pp.277-283
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• 2003

In a closed-die forging process, blocker has been used to fill and distribute metal well in finisher die. Generally, the blocker shape was determined by an expert with many experiences. However, the manual blocker design process takes much time and efforts, so various automatic methods for the blocker design process have been suggested for the last three decades. The method with filtering in FFT (Fast Fourier Transform) for the blocker design provides general solution than other methods. But. due to the properties of FFT in time-frequency domain, this method has some drawbacks such as long calculation time, difficulty of local control and additional boundary process after filtering. In this study. DWT (Discrete Wavelet Transform), which is more flexible and is more wildly used than FFT, is applied to the blocker design. The method with filtering in DWT is very proper to design blocker in both 2-D and 3-D shapes. To verify the efficiency of this method, blockers of some models are designed and the results show that blocker design with DWT is effective for the blocker designs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.8
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• pp.3389-3404
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• 2012

Based on the case study methods, the study analyzes emergence and ensuing typology of global ebook platforms such as Google eBook, Amazon Kindle, iBooks Store. Global ebook platforms show adaptation process responding to rapidly changing digital technological envirment and it's fitness landscape. The critical elements in its emerging process are the distinct selection criteria, the degree of resource abundance and the search process based on open innovation. Based on these critical elements, the global platforms show speciation process, so called niche creation and are evolving into a variety of the typology based on the initial condition of key resource which makes the platform emerge and grow. Each global ebook platforms is evolving into open platform, hybrid platform, closed platform. Google eBook has openness and extensibility due to a variety of devices based on Android and a direct involvement of actors. Amazon Kindle has developed from a online bookstore and into the hybrid platform which have not only closed quality but also openness with ebook devices and mobile network. iBooks Store has developed into the closed platform through the agency model based on competitive hardwares and closed quality with iphone and ipad.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.8
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• pp.82-91
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• 1997

The major objective of this study is to establish analytical technique in order to analyze the behaviour of semi-solid material considering induction heating of the billet. Induction heating process is analyzed by using commerical finite element software. ANSYS. The finite element program, SFAC2D, for the simulation of deformation in semi-solid state is developed in the present study. The semi-solid behaviour is described by a viscoplastic model for the solid phase, and by the Darcy's law for the liquid flow. Simple compression and closed-die compression process considering induction heating are analyzed, and also it is found that the distribution of initial solid fraction of the billet has an important effect on deformation behaviour of semi-solid material. In order to verify the effectiveness of proposed analytical technique the simulation result is compared with experimental result.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.263-266
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• 2008

We apply a closed die forging technology to a large crankshaft of which forging weight amounts to 850kg. 40ton counter-blow hammer forging machine is used. The forging process is optimized to reduce the forming load using finite element simulation. AFDEX 3D is used for forging simulation. The experiment is compared with finite element prediction and a good agreement is observed. The successful development of a large crankshaft by the closed die forging technology will contribute to opening a new area of closed-die forging application and to enhancing competitiveness of national machinery industries especially including ship part and power generation industries.