• Proceedings of the Materials Research Society of Korea Conference
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• 2010.05a
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• pp.20.1-20.1
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• 2010

'Electronic paper (EP)' provides desirable viewing characteristics of paper with being thin, lightweight, flexible, and recordable with minimal power consumption. Currently, a number of different technologies to realize the EP are actively competing. Here we demonstrate a newly developed monolayer rotating ball (MRB) electronic paper display where optically anisotropic rotating balls were disposed in a monolayer, and controllably closely packed with respect to one another. The close packed monolayer configuration provides high brightness and improved contrast with better electrical and optical features in comparison with the typical (Gyrion) rotating ball display. In this talk, we present characteristics of the MRB display in terms of performance, with particular emphasis on the response time as a function of the electric field.

• Structural Engineering and Mechanics
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• v.43 no.1
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• pp.1-13
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• 2012

A fast precise integration method (FPIM) is proposed for solving structural dynamics problems. It is based on the original precise integration method (PIM) that utilizes the sparse nature of the system matrices and especially the physical features found in structural dynamics problems. A physical interpretation of the matrix exponential is given, which leads to an efficient algorithm for both its evaluation and subsequently the solution of large-scale structural dynamics problems. The proposed algorithm is accurate, efficient and requires less computer storage than previous techniques.

• Interaction and multiscale mechanics
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• v.3 no.2
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• pp.173-191
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• 2010

Damage detection plays a very important role to the maintenance of bridge structures. Traditional damage detection methods are usually based on structural dynamic properties, which are acquired from pre-installed sensors on the bridge. This is not only time-consuming and costly, but also suffers from poor sensitivity to damage if only natural frequencies and mode shapes are concerned in a noisy environment. Recently, the idea of using the dynamic responses of a passing vehicle shows a convenient and economical way for damage detection of bridge structures. Inspired by this new idea and the well-established tap test in the field of non-destructive testing, this paper proposes a new method for obtaining the damage information through the acceleration of a passing vehicle enhanced by a tapping device. Since no finger-print is required of the intact structure, this method can be easily implemented in practice. The logistics of this method is illustrated by a vehicle-bridge interaction model, along with the sensitivity analysis presented in detail. The validity of the method is proved by some numerical examples, and remarks are given concerning the potential implementation of the method as well as the directions for future research.

• Korean Journal of Computational Design and Engineering
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• v.8 no.1
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• pp.19-26
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• 2003

This paper presents the structural analysis of RIROB(Reactor Inspection Robot). Actually, several analyses such as kinetodynamics analysis, fluid mechanics analysis and structural mechanics analysis etc. should be carried out in the design of RIROB. These analyses are executed through the use of com-puter aided engineering(CAE) systems. The kinetodynamics analysis is carried out using a simple fluid dynamic analysis model for the water flow over the sensor support surface instead of difficult fluid mechanics analysis. Simultaneously the structural mechanics analysis is carried out to obtain the mini-mum thickness of the RIROB housing. The minimum thickness of the RIROB housing is evaluated to be 1.0 ㎝ for the safe design of RIROB. The kinetodynamics analysis of RIROB is performed using ADAMS and the static structural mechanics analysis of RIROB is performed using NISA.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.532-534
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• 2008

LCD TV용 Backlight Unit을 구동하는 Inverter 및 SMPS용 IC의 발진기(OSC)는 구동 주파수를 결정하는 블록이다. 종래에는 미리 결정된 전류값과 충방전용 시정수에 의하여 스위칭 주파수가 고정 되어 있다. 이에 반하여 외부에서 스위칭 주파수를 가변하고자 할 때, 신호의 입력에 따라 스위칭 주파수가 가변 가능한 발진기(Oscillator) 블록을 제안한다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.613-614
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• 2006

• Structural Engineering and Mechanics
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• v.21 no.6
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• pp.621-634
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• 2005

A direct transfer substructure method is presented in this paper for analyzing the dynamic characteristics and the seismic random responses of a series reactor. This method combines the concept of FRF (frequency response function) and the transfer matrix algorithm with the substructure approach. The inner degrees of freedom of each substructure are eliminated in the process of reconstruction and the computation cost is reduced greatly. With the convenient solution procedure, the dynamic characteristics analysis of the structure is valid and efficient. Associated with the pseudo excitation algorithm, the direct transfer substructure method is applied to investigating the seismic random responses of the series reactor. The numerical results demonstrate that the presented method is efficient and practicable in engineering. Finally, a precise time integration method is employed in performing a time-history analysis on the series reactor under El Centro and Taft earthquake waves.

• Structural Engineering and Mechanics
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• v.6 no.5
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• pp.529-542
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• 1998

Generalised plane strain solution is presented for simply supported, angle-ply laminated hybrid plate under cylindrical bending. The arbitrary constants in the general solution of the governing differential equations are obtained from the boundary and interface conditions. The response of hybrid plates to sinusoidal loads is obtained to illustrate the effect of the thickness parameter and the ply-angle. The classical lamination theory and the first order shear deformation theory are also assessed.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2007.04a
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• pp.81-100
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• 2007

• Multiscale and Multiphysics Mechanics
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• v.1 no.2
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• pp.171-188
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• 2016

Gradient enhanced theories of crystal plasticity enjoy great research interest. The focus of this work is on thermodynamically consistent modeling of grain size dependent hardening effects. In this contribution, we develop a model framework for damage coupled to gradient enhanced crystal thermoplasticity. The damage initiation is directly linked to the accumulated plastic slip. The theoretical setting is that of finite strains. Numerical results on single-crystalline metal showing the development of damage conclude the paper.