• Proceedings of the Korean Society of Marine Engineers Conference
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• 2006.06a
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• pp.51-52
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• 2006

This study was progressed on the freezing behavior of waste water in relation to freeze concentration method useful to waste water treatment system of small and middle size and which can re-use purified water. The object of this experiment is comparing a pollutant contain of the frozen layer and of an aqueous solution by cooling wall temperature, a flow field effect and a initial thickness of frozen layer.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05a
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• pp.1-5
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• 2004

In this paper, we propose a novel approach for evolving the architecture of a multi-layer neural network. Our method uses combined ART1 algorithm and Max-Min neural network to self-generate nodes in the hidden layer. We have applied the. proposed method to the problem of recognizing ID number in student identity cards. Experimental results with a real database show that the proposed method has better performance than a conventional neural network.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.618-621
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• 2008

In this paper a new smoothing method of unstructured viscous grid which can be useful when the ALM(Advacning Layer Method) method is used to generate volume grids of prism cells starting with unstructured triangular surface grids. According to the new method two layers of prism cells in the advancing direction which are found by the vector smoothing method are first generated, and then the position of nodes along the middle layer are adjusted by using spring analogy. It is found that the proposed method improves grid quality of the unstructured viscous volume grids for body shape with convex and concave corners.

• Earthquakes and Structures
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• v.3 no.3_4
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• pp.383-411
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• 2012

The objective of the present paper is to review and implement the most recent developments in the Spectral Element Method (SEM), as well as improve aspects of its implementation in the study of wave propagation by numerical simulation in elastic unbounded domains. The classical formulation of the method is reviewed, and the construction of the mass matrix, stiffness matrix and the external force vector is expressed in terms of matrix operations that are familiar to earthquake engineers. To account for the radiation condition at the external boundaries of the domain, a new absorbing boundary condition, based on the Perfectly Matched Layer (PML) is proposed and implemented. The new formulation, referred to as the Multi-Axial Perfectly Matched Layer (M-PML), results from generalizing the classical Perfectly Matched Layer to a medium in which damping profiles are specified in more than one direction.

• Journal of Pharmaceutical Investigation
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• v.37 no.1
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• pp.7-13
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• 2007

To produce stable polymer coating layer using the interaction between metal stent and polymer layer, Ahx-HSAB was synthesized by coupling 6-aminoheanoic acid (Ahx) with N-Hydroxy succinimidyl 4-azidobenzonate (HSAB) containing photo reactive group. Then, Ahx-HSAB was applied to self·assembled monolayer (SAM) on $TiO_2$-coated surface, since one end of Ahx-HSAB was carboxyl acid which was known to be able to interact with $TiO_2$ surface. That SAM layer was incubated in 1% polycaprolacton (PCL) solution and photoreacted by ultraviolet light (254 nm) to produce the chemical bond between SAM and polymer layer, followed by PCL polymer coating ({\sim}5\;{\mu}m$) by the method of spray coating. The surface change was investigated by measuring of contact angle of the surface. The contact angle values of stainless steel (SS) surface, $TiO_2$-coated surface, SAM layer by Ahx-HSAB, photoreacted surface with PCL and PCL layer by spray coating were 70.48${\pm}$1.89, 38.57${\pm}$3.31, 60.14${\pm}$2.21, 54.91${\pm}$2.70 and 56.47${\pm}$2.12, respectively. The stability of polymer layers was tested by incubation of PCL-coated plates in 0.1M PBS buffer (pH 7.4, 0.05%, Tween 80) with vigorous shaking (200 rpm). While the poiymer layer prepared by these processes showed the intact surface morphology over 3 days, the polymer layers prepared by spray coating of PCL onto SS plate (control 1) and $TiO_2$-coated SS plate (control 2) were Peeled off in 3 days. Thus, the polymer coating method using SAM and photoreaction seems to be a effective method to obtain the stable polymer layer onto SS surface.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.71-81
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• 2008

This paper proposes a spectral element which can represent dynamic responses in high frequency domain such as Lamb waves on a thin plate. A two layer beam model under 2-D plane strain condition is introduced to simulate high-frequency dynamic responses induced by piezoelectric layer (PZT layer) bonded on a base plate. In the two layer beam model, a PZT layer is assumed to be rigidly bonded on a base beam. Mindlin-Herrmann and Timoshenko beam theories are employed to represent the first symmetric and anti-symmetric Lamb wave modes on a base plate, respectively. The Bernoulli beam theory and 1-D linear piezoelectricity are used to model the electro-mechanical behavior of a PZT layer. The equations of motions of a two layer beam model are derived through Hamilton's principle. The necessary boundary conditions associated with electro mechanical properties of a PZT layer are formulated in the context of dual functions of a PZT layer as an actuator and a sensor. General spectral shape functions of response field and the associated boundary conditions are formulated through equations of motions converted into frequency domain. A detailed spectrum element formulation for composing the dynamic stiffness matrix of a two layer beam model is presented as well. The validity of the proposed spectral element is demonstrated through comparison results with the conventional 2-D FEM and the previously developed spectral elements.

• Journal of the Korea Society of Computer and Information
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• v.4 no.3
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• pp.67-72
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• 1999

The neural network is a static network that consists of a number of layer: input layer, output layer and one or more hidden layer connected in a feed forward way. The popularity of neural network appear to be its ability of learning and approximation capability. The Elman Neural Network proposed the J. Elman. is a type of recurrent network. Is has the feedback links from hidden layer to context layer. So Elman Neural Network is the better performance than the neural network. In this paper. we propose the Modified Elman Neural Network. The structure of a MENN is based on the basic ENN. The recurrency of the network is due to the feedback links from the output layer and the hidden layer to the context layer. In order to certify the usefulness or the proposed method. the MENN apply to the multi target system. Simulation shows that the proposed MENN method is better performance than the multi layer neural network and ENN.

• Computers and Concrete
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• v.27 no.3
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• pp.199-210
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• 2021

The aim of this paper was to examine the continuous and discontinuous contact problems between the functionally graded (FG) layer pressed with a uniformly distributed load and homogeneous half plane using an analytical method and FEM. The FG layer is made of non-homogeneous material with an isotropic stress-strain law with exponentially varying properties. It is assumed that the contact at the FG layer-half plane interface is frictionless, and only the normal tractions can be transmitted along the contacted regions. The body force of the FG layer is considered in the study. The FG layer was positioned on the homogeneous half plane without any bonds. Thus, if the external load was smaller than a certain critical value, the contact between the FG layer and half plane would be continuous. However, when the external load exceeded the critical value, there was a separation between the FG layer and half plane on the finite region, as discontinuous contact. Therefore, there have been some steps taken in this study. Firstly, an analytical solution for continuous and discontinuous contact cases of the problem has been realized using the theory of elasticity and Fourier integral transform techniques. Then, the problem modeled and two-dimensional analysis was carried out by using ANSYS package program based on FEM. Numerical results for initial separation distance and contact stress distributions between the FG layer and homogeneous half plane for continuous contact case; the start and end points of separation and contact stress distributions between the FG layer and homogeneous half plane for discontinuous contact case were provided for various dimensionless quantities including material inhomogeneity, distributed load width, the shear module ratio and load factor for both methods. The results obtained using FEM were compared with the results found using analytical formulation. It was found that the results obtained from analytical formulation were in perfect agreement with the FEM study.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.7
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• pp.814-820
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• 2011

It takes long time in numerical simulation because structural design for tire requires the nonlinear material property. Neural networks has been widely studied to engineering design to reduce numerical computation time. The numbers of hidden layer, hidden layer neuron and training data have been considered as the structural design variables of neural networks. In application of neural networks to optimize design, there are a few studies about arrangement method of input layer neurons. To investigate the effect of input layer neuron arrangement on neural networks, the variables of tire contour design and tension in bead area were assigned to inputs and output for neural networks respectively. Design variables arrangement in input layer were determined by main effect analysis. The number of hidden layer, the number of hidden layer neuron and the number of training data and so on have been considered as the structural design variables of neural networks. In application to optimization design problem of neural networks, there are few studies about arrangement method of input layer neurons. To investigate the effect of arrangement of input neurons on neural network learning tire contour design parameters and tension in bead area were assigned to neural input and output respectively. Design variables arrangement in input layer was determined by main effect analysis.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.57 no.4
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• pp.408-411
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• 2008

As to this research is new structure of the semiconductor substrate heating apparatus. The fast thermoresponsive according to the direct heating structure of the heating plate layer adhering closely to the floor side of a substrate and the fast heat loss minimization can be accomplished. Moreover, the contact area of the sheath heater, which is the heating plate layer built-in heating apparatus, is increased, so that it has more heating valid area. For this, it adheres closely to the substrate, in which the photosensitive film is coated and the heating plate layer, adhering closely to the floor side of a substrate the mica layer which adheres closely to the floor side of the upper heating plate layer in order to minimize an insulation and heat loss, and the lower part of the mica layer and it is comprised of the floor plate layer. The heating plate layer forms the continued groove portion over the floor side whole. The sheath heater for heating a substrate is inserted with the groove portion and the heating plate layer is comprised. It is confirmed that by using the new substrate heating structure, the temperature change of the heating plate against the time is observed. Then, there is the electric power saving effect of about 40% in comparison with the existing method.