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690 results on '"Choi, Kyung Hyun"'

170. 3D printing for soft robotics – a review

Author

Gul, Jahan Zeb, primary, Sajid, Memoon, additional, Rehman, Muhammad Muqeet, additional, Siddiqui, Ghayas Uddin, additional, Shah, Imran, additional, Kim, Kyung-Hwan, additional, Lee, Jae-Wook, additional, and Choi, Kyung Hyun, additional

Published
2018
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176. Multi-agent hybrid shop floor control system.

Author

Choi, Kyung-Hyun, Kim, Sung-Chung, and Yook, Sung-Hoon

Subjects
PRODUCTION control, SUPERVISORY control systems
Abstract

A manufacturing system is composed of many activities that can be monitored and controlled at different levels of abstraction. A shop floor can be considered an important level at which to develop a Computer Integrated Manufacturing system (CIM). However, a shop floor is the dynamic environment where unexpected events continuously occur, and impose changes to planned activities. To deal with this problem, the shop floor should adopt an appropriate control system that is responsible for the coordination and control of the manufacturing physical flow and information flow. In this paper, a hybrid control system is described with a shop floor activity methodology called Multi-Layered Task Initiation Diagram (MTD). The architecture of the control model identifies three levels; i.e. the shop floor controller (SFC), the intelligent agent controller (IAC) and the equipment controller (EC). The methodology behind the development of the control system is an intelligent multi-agent paradigm that enables the shop floor control system to be an independent, autonomous, and distributed system, and to achieve an adaptability to change the manufacturing environment. [ABSTRACT FROM AUTHOR]

Published
2000
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178. Solution processed fabrication of single wall carbon nanotubes thin film by electrohydrodynamic atomization deposition technique and its characterization

Author

Duraisamy Navaneethan, Kim Hyung Chan, Hyeoun Myung Taek, Choi Kyung Hyun, and Mustafa Maria

Subjects
Fabrication, Materials science, Scanning electron microscope, Nanotechnology, General Chemistry, Carbon nanotube, law.invention, Volumetric flow rate, law, Deposition (phase transition), General Materials Science, Electrohydrodynamics, Thin film, Composite material, Dispersion (chemistry)
Abstract

An effective method for the fabrication of thin film of single wall carbon nanotubes (SWCNT) using the electro-hydrodynamic atomization (EHDA) deposition technique was demonstrated. In this study, the SWCNT aqueous based dispersion ink was subjected to electrostatic atomization by using an EHDA deposition system. The ink flow visualization under the influence of electric field was performed and the operating EHDA parametric envelope of the ink was explored. Then the deposition of SWCNT through the EHDA process was carried out onto a metallic substrate at a fixed flow rate and corresponding applied voltage thereby achieving thickness ranging from ∼70 to 130 nm by making multiple deposition passes. The microscopic inspection of the film was performed and thin film quality was examined by scanning electron microscope analysis. Finally, electrical behavior of the SWCNT film onto a metallic substrate through temperature dependent current-voltage measurements was investigated. The SWCNT film deposited onto the metallic substrate showed electrical conductivity of ∼2.98 S/cm.

Published
2012

179. An new approach for intelligent control system design using the modified genetic algorithm

Author

Choi, Kyung-Hyun, Thanh, Tran Trung, Su, Yang Bong, and Kim, Dong-Soo

Subjects
Genetic algorithms -- Usage, Intelligent control systems -- Design and construction, Intelligent control systems -- Analysis, Computers and office automation industries
Abstract

Byline: Kyung-Hyun Choi, Tran Trung Thanh, Yang Bong Su, Dong-Soo Kim There are many applications which employed roll-to-roll web technology for mass production to make cheaper production in shorter time. Especially, RFID and printed electronics using the principle of roll-to-roll manufacturing to build equipment at high speeds will have a big impact on the printed electronics. To increase the precision and flexible ability to detect effectively the external and internal disturbance, several controller designs for roll-to-roll web control system are proposed in recent years. However, almost all proposals are employed for the time-invariant linear SISO systems. In reality, some terms in several control systems such as roll-to-roll web system change in time and are non-linear. Therefore, classical gain tuning approaches are not suitable. In this paper, an algorithm proposed for non-linear roll-to-roll web control system is based on using the modified genetic algorithm to determine the optimal parameters of controller, detect the errors and automatically recover the errors at every time interval. The simulation results in Matlab/Simulink employed firstly with the simple plants and after that with back-stepping controllers of roll-to-roll system prove the stability and reliability of the proposed approach.

Published
2010

200. 3D printed highly flexible strain sensor based on TPU–graphene composite for feedback from high speed robotic applications.

Author

Gul, Jahan Zeb, Sajid, Memoon, and Choi, Kyung Hyun

Abstract

A novel, highly flexible and electrically resistive-type strain sensor with a special three-dimensional conductive network was 3D printed using a composite of conductive graphene pellets and flexible thermoplastic polyurethane (TPU) pellets. The morphology of the TPU graphene filament was verified using Raman spectroscopy. The composite filament was well fused and constructed an excellent three-dimensional conductive network. The size of the 3D printed strain sensor was 2 × 1.5 cm (length × width) and the layer had a depth of 200 μm. The special hierarchical conductive network endowed the 3D printed strain sensor with a desirable combination of good stretchability and a high sensitivity (gauge factor (GF) of 11 in a strain of 10% and 80 in a strain of 100% in a reversible strain regime), good durability and stability (stretch/release test of 6000 cycles) and a rapid response speed. The mechanism of evolution for the residual resistance and residual strain of the 3D printed strain sensor under cyclic loading were investigated in detail. The strain sensor was embedded inside a 3D printed Polylactic acid (PLA) based finger hinge and the bending feedback was observed. The results demonstrate that our flexible strain sensor has the potential for wide ranging applications in soft actuators, feedback from high speed robotic applications and 3D printed wearable devices. [ABSTRACT FROM AUTHOR]

Published
2019
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