• Journal of Korean Society of Industrial and Systems Engineering
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• v.19 no.39
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• pp.193-204
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• 1996

본 연구는 FMC(Flexible Manufacturing Cell)에 있어 상호 간섭이 없는 부품의 흐름을 제어하기 위한 교착제거방법(Deadlock Avoidance Method)에 대한 제안으로서, 이 방법이 주요한 장점은 첫째, FMC의 환경을 쉽게 적용시킬 수 있고 둘째, 공정상의 부품에 대한 dispatching 모듈이 협력하도록 설계되어 있다는 것이다. 교착제거방법은 두 개의 모듈로 구성되어 있는데 이는 순환발견알고리즘(A Cycle Detection Algorithm)과 원료주문 정책으로서, 특이할 만한 사항은 순환발견알고리즘을 채용하더라도 원료주문정책이 잘못될 수 있기 때문에 교착제거방법에 있어서 원료주문정책은 매우 중요하다는 것이다. 이를 위하여 교착전의 N-step 교착을 제거하고, 발견할 수 있는 교착제거방법과 N-step의 사전주무정책을 제시하였다.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.11
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• pp.147-153
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• 1997

Fault diagnosis technique in machining system which is one of engineering techniques absolutely necessary to automation of manufacturing system has been proposed. As a whole, diagnosis process is explained by two steps: sensor data acquisition and reasoning current state of system with the given sensor data. Flexible disk grinding process implemented in milling machine was employed in order to obtain empirical manufacturing process information. Resistance force data during machining were acquired using tool dynamometer known as sensor which is comparably accurate and reliable in operation. Tool status during the process was analyzed using influnece diagram assigning probability from the statistical analysis procedure.

• Transactions of Materials Processing
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• v.22 no.5
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• pp.243-249
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• 2013

The multi-point forming (MPF) process for three-dimensional curved sheet metal has been developed as an alternative to the conventional die forming process since MPF allows the manufacturing of various shapes using one die set and reduce the cost of production. However, the MPF process cannot provide high quality products yet due to defects occurring in the sheet such as dimples and wrinkles. It can also lead to economic loss because of long tool setup time and additional machining required outside of the sheet formed area. In this study, a new sheet metal forming method, called flexible roll forming (FRF), is proposed to solve the problems of existing processes for three-dimensional curved sheet metal. This progressive process utilizes adjusting rods, as well as upper and lower flexible rollers as forming tools. In contrast with the existing processes, FRF can reduce the additional production costs because of the possible blank size for the part longitudinal direction, which is unrestricted. In this research, methods and procedures of the flexible roll forming technology are described. Numerical forming simulations of representative three-dimensional curved sheet products are also carried out to demonstrate the feasibility of this technology.

• International Journal of Precision Engineering and Manufacturing
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• v.5 no.4
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• pp.50-60
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• 2004

A very flexible beam can be used to model various types of continuous mechanical parts such as cables and wires. In this paper, the dynamic properties of a very flexible beam, included in a multibody system, are analyzed using absolute nodal coordinates formulation, which is based on finite element procedures, and the general continuum mechanics theory to represent the elastic forces. In order to consider the dynamic interaction between a continuous large deformable beam and a rigid multibody system, a combined system equations of motion is derived by adopting absolute nodal coordinates and rigid body coordinates. Using the derived system equation, a computation method for the dynamic stress during flexible multibody simulation is presented based on Euler-Bernoulli beam theory, and its reliability is verified by a commercial program NASTRAN. This method is significant in that the structural and multibody dynamics models can be unified into one numerical system. In addition, to analyze a multibody system including a very flexible beam, formulations for the sliding joint between a very deformable beam and a rigid body are derived using a non-generalized coordinate, which has no inertia or forces associated with it. In particular, a very flexible catenary cable on which a multibody system moves along its length is presented as a numerical example.

• Ceramist
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• v.22 no.2
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• pp.122-132
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• 2019

Wearable electronic devices with batteries must be lightweight, flexible and highly durable. Most importantly, the battery should be able to self-generate to operate the devices without having to be too frequently charged externally. An eco-friendly energy harvesting technology from various sources, such as solar energy, electromagnetic energy and wind energy, has been developed for a self-charging flexible battery. Although the energy harvesting from such sources are often unstable according to the surrounding environment, the energy harvesting from body movements and vibrations has been less affected by the surrounding environment. In this regard, flexible piezoelectric modules are the most attractive solution for this issue, because they convert mechanical energy to electrical energy and harvest energy from the human body motions. Among the various flexible piezoelectric modules, piezoelectric nanofibers have advantages when used as an energy harvester in wearable devices, due to their simple manufacturing process with good applicability to polymers and ceramics. This review focused on diverse flexible piezoelectric nanofibers and discusses their applications as various energy harvesting systems.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.1
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• pp.105-112
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• 2023

We analyze the global market for flexible electronic circuits, technical considerations, and analyze the market for application areas and regions. In the market analysis of the application field, the display field has the greatest influence in terms of market size and annual growth rate, and the OLE D lighting market size is expected to grow by nearly 50% in 2026. The multilayer flexible electronics, which dependently requires the semiconductor technology, has a larger market size than other structures and its growth rate is relatively large, leading the market and will be further analyzed in depth. The market size of multilayer flexible electronics applied to display field is expected to show an annual growth rate of 21.1% from $2.7 billion in 2017 to $9.8 billion in 2026, and the OLED market is expected to grow by 75.2% during the same periods. Recently, as electronic products have been miniaturized and advanced, and robust installation in a small space is required, companies that preoccupy multilayer structure or rigid flexible electronic circuit technology have an advantage in competitiveness, so many companies are trying to obtain this technology. These efforts are systematically supported by many countries because they can achieve mutual growth by strengthening the competitiveness of the application field and the same industry. In the case of Korea, a support system is established, but it is required to expand and activate it, and to localize manufacturing equipment and materials.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.449-450
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• 2012

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1993.04a
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• pp.23-23
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• 1993

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1992.04b
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• pp.27-27
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• 1992

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1994.04a
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• pp.247-247
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• 1994