• Journal of the Institute of Convergence Signal Processing
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• v.8 no.1
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• pp.51-57
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• 2007

In this paper we introduce the concept of MPLS-based VPN and propose a scheme for providing VPN services in MPLS networks. Furthermore, we design the control components and the operational procedures and evaluated the performance of traditional VPN implementation methods and MPLS-based VPN. In this scheme it is possible to solve several problems that IP-based VPN pertains via the allocation of VPN ID and virtual space without tunneling, thereby providing effective VPN services. In other words, the MPLS-based VPN scheme uses MPLS networking technology together with the PSTN which can achieve a perfect segregation of user traffic on per-customer basis in a physical link and can guarantee high reliability and security levels. Specially, in the perspective of customers, it can save networking facilities installation and maintenance costs considerably. On the contrary, it possesses some shortcomings in that its deployment tends to be restricted within an ISP's network boundary and it is vulnerable to external security break-ins when going through public networks such as the Internet due to its lack of data encryption capability.

• Journal of the Korea Society of Computer and Information
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• v.17 no.4
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• pp.51-58
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• 2012

Recently, 3D technology based on depth image is widely used in various fields including 3D space recognition, image acquisition, interaction, and games. Depth camera is used in order to produce depth image, various types of effort are made to improve quality of the depth image. In this paper, we suggests using area-based Canny edge detector to improve depth image in applying 3D technology based on depth camera. The suggested method provides improved depth image with pre-processing and post-processing by fixing image quality deterioration, which may take place in acquiring depth image in a limited environment. For objective image quality evaluation, we have confirmed that the image is improved by 0.42dB at maximum, by applying and comparing improved depth image to virtual view reference software. In addition, with DSCQS(Double Stimulus Continuous Quality Scale) evaluation method, we are reassured of the effectiveness of improved depth image through objective evaluation of subjective quality.

• Structural Engineering and Mechanics
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• v.66 no.3
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• pp.353-368
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• 2018

In this work, a high order hyperbolic shear deformation theory with four variables is presented to study the vibratory behavior of functionally graduated plates. The field of displacement of the theory used in this work is introduced indeterminate integral variables. In addition, the effect of porosity is studied. It is assumed that the material characteristics of the porous FGM plate, varies continuously in the direction of thickness as a function of the power law model in terms of volume fractions of constituents taken into account the homogeneous distribution of porosity. The equations of motion are obtained using the principle of virtual work. An analytical solution of the Navier type for free vibration analysis is obtained for a FGM plate for simply supported boundary conditions. A comparison of the results obtained with those of the literature is made to verify the accuracy and efficiency of the present theory. It can be concluded from his results that the current theory is not only accurate but also simple for the presentation of the response of free vibration and the effect of porosity on the latter.

• Steel and Composite Structures
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• v.25 no.1
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• pp.105-116
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• 2017

This paper presents the dynamic stability study of laminated composite plates with different force combinations and aspect ratios. Optimum non-diverging stacking is obtained for certain loading combination and aspect ratio. In addition, the stability force is maximized for a definite operating frequency. A dynamic version of the principle of virtual work for laminated composites is used to obtain force-frequency relation. Since dynamic stiffness governs the divergence or flutter, an efficient optimization method is necessary for the response functional and the relevant constraints. In this way, a model based on the ant colony optimization (ACO) algorithm is proposed to search for the proper stacking. The ACO algorithm is used since it treats with large number of dynamic stability parameters. Governing equations are formulated using classic laminate theory (CLT) and von-Karman plate technique. Load-frequency relations are explicitly obtained for fundamental and secondary flutter modes of simply supported composite plate with arbitrary aspect ratio, stacking and boundary load, which are used in optimization process. Obtained results are compared with the finite element method results for validity and accuracy convince. Results revealed that the optimum stacking with stable dynamic response and maximum critical load is in angle-ply mode with almost near-unidirectional fiber orientations for fundamental flutter mode. In addition, short plates behave better than long plates in combined axial-shear load case regarding stable oscillation. The interaction of uniaxial and shear forces intensifies the instability in long plates than short ones which needs low-angle layup orientations to provide required dynamic stiffness. However, a combination of angle-ply and cross-ply stacking with a near-square aspect ratio is appropriate for the composite plate regarding secondary flutter mode.

• Korean Institute of Interior Design Journal
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• v.18 no.6
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• pp.96-103
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• 2009

Man has an unconscious desire to free oneself from everyday selves and a strong intellectual desire to see and analyze things in a different perspective. This provided a momentum for architectural design that has long been confined to its limits of modernism of being rational and objective. The ever-changing society that we live in filled with various attempts and pluralistic characteristics shows a complex set of attributes that can hardly be defined by a single term. As society moves towards an uncertain and volatile state, the boundary between literature, philosophy and art has dimmed out and converged. Such tendencies have been observable in recent establishments in architecture in the form of introducing external elements and create an alien and farfetched architectural space. Using the 'depaysement' defamiliarization method expressing irrationality and randomness, it is applied in various aspects, sharing the counter-rational structure and features of such architectural space. Hence, it is the purpose of this study to delve into the unique characteristics of depaysement through Magritte's work which reflects the unique pictorial world built under the influence of surrealism, and discover the $D\acute{e}paysement$ tendencies in modern architectural space. It is apparent in Modern architecture that, owing to the development in digital technology, it is showing process changes in design and an interfacial $D\acute{e}paysement$ effect in cyberspace, an interlace of reality and the virtual world. In this study, the focus of analysis was architectural properties such as the program, figure/spatial, material and the objective side, but due to mutual text properties, it is bound to be an overlapping analysis.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.963-966
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• 2005

Model updating method is known to the area to correct finite element models by the results of the experimental modal analysis. Most common methods in model updating depend on a parametric model of the structure. In this case, the number of parameters is normally smaller than that of modal data obtained from an experiment. In order to overcome this limitation, many researchers are trying to get modal data as many as possible to date. 1 want to name this method multiple modified-system generation method. These Methods consist of direct system modification method and feedback controller method. The direct system modification Is to add a mass or stiffness on the original structure or perturb the boundary conditions. The feedback controller method is to make the closed food system with sensor and actuator so as to get the closed loop modal data. In this paper, we need to focus on the feedback controller method because of its simplicity. Several methods related the feedback controller methods are virtual passive controller (VPC) sensitivity enhancement controller (SEC) and mode decoupling controller (MDC). Among them, we will apply MDC to the model updating problem. MDC has various advantages compared with other controllers, such as VPC and SEC. To begin with, only the target mode can be changed without changing modal property of non-target modes. In addition, it is possible to fix any modes if the number of sensors is equal to that of the system modes. Finally, the required control power to achieve desired change of target mode is always lower than those of other methods such as VPC. However, MDC can make the closed loop system unstable when using incomplete modal data. So we need to take action to avoid undesirable instability from incomplete modal data. In this paper, we address the method to design the unique and robust MDD obtained from incomplete modal data. The associated simulation will be Incorporated to demonstrate the usefulness of this method.

• The Journal of Art Theory & Practice
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• no.5
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• pp.83-107
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• 2007

The continuous struggle to establish virtual reality on the stage during the history of Western Theater has been centered upon the development of scenographic setting and devices. It began with the Classical Greek drama where the place of performance became separated from the place of the audience. These two places were united as the orchestra - the place of the Dionysiac festival in the earliest stage of the Greek theater. And the skene, once a storage building outside the theatrical area, became an essential factor of the scenic space to provide illusion of the other world where the actors dwell. As a natural consequence it followed the structural change of Roman theater where the stage became a high and wide platform and the skene converted into the permanent stone scaenae frons. Such a tradition of the Classical theater was revived in Italian Renaissance and Baroque theater, which succeeded Vitruvius' concept of scaenographia as well as the vestiges of Imperial Roman theater. The cases of Serlio, Palladio, and Andrea Pozzo reveal the way how Western theater conjured the fictional space by traditional representational scenery, including architectural background setting and painted devices. It resulted in the physical and emotional division of actors' space and audience's space. The rejection of representational scenery upon the stage by avant garde artists like Edward Gordon Craig in the early years of the twentieth century should be interpreted as an attempt to recover an emotional attachment of actors and the audience, which was the case of Greek antiquity. This new scenogrpahic endeavor in modern theater is to challenge the main purpose of traditional scaenae frons to establish the boundary of the illusional 'scene' of performance where the audience should remain as passive spectators, and instead, to try to unite the action of actors and the audience upon the stage as a 'place'.

• Structural Engineering and Mechanics
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• v.74 no.3
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• pp.365-380
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• 2020

The focus of this paper is to develop an analytical approach based on an efficient shear deformation theory with stretching effect for bending stress analysis of cross-ply laminated composite plates subjected to transverse parabolic load and line load by using a new kinematic model, in which the axial displacements involve an undetermined integral component in order to reduce the number of unknowns and a sinusoidal function in terms of the thickness coordinate to include the effect of transverse shear deformation. The present theory contains only five unknowns and satisfies the zero shear stress conditions on the top and bottom surfaces of the plate without using any shear correction factors. The governing differential equations and its boundary conditions are derived by employing the static version of principle of virtual work. Closed-form solutions for simply supported cross-ply laminated plates are obtained applying Navier's solution technique, and the numerical case studies are compared with the theoretical results to verify the utility of the proposed model. Lastly, it can be seen that the present outlined theory is more accurate and useful than some higher-order shear deformation theories developed previously to study the static flexure of laminated composite plates.

• Journal of the Korea Institute of Building Construction
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• v.19 no.1
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• pp.39-46
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• 2019

A three-dimensional flow simulation model for high flow concrete was developed using Incompressible Smoothed Particle Hydrodynamics (ISPH), which can solved Navier-Stokes equation with the assumption of a fluid to be incompressible. For the simulation, a computer program code for ISPH was implemented with MATALB programming code. A piecewise cubic spline function was used for the kernel function of ISPH. Projetion method was used to calculate the velocity and pressure of particles as a function of time. Fixed ghost particle was used for wall boundary condition. Free surface boundaries were determined by using virtual density of particles. In order to validate the model and the code, the simulation results of slump flow test, $T_{500}$ test and L-box test were compared with experimental ones. The simulation results were well matched with the experimental results. The simulation described successfully the characteristics of the flow phenomenon according to the change of the viscosity and yield stress of high flow concrete.

• Steel and Composite Structures
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• v.43 no.6
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• pp.821-837
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• 2022

This research is devoted to study the effects of humidity and temperature on the bending behavior of functionally graded (FG) ceramic-metal porous plates resting on Pasternak elastic foundation using a quasi-3D hyperbolic shear deformation theory developed recently. The present plate theory with only four unknowns, takes into account both transverse shear and normal deformations and satisfies the zero traction boundary conditions on the surfaces of the functionally graded plate without using shear correction factors. Material properties of porous FG plate are defined by rule of the mixture with an additional term of porosity in the through-thickness direction. The governing differential equations are obtained using the "principle of virtual work". Analytically, the Navier method is used to solve the equations that govern a simply supported FG porous plate. The obtained results are checked by comparing the results determined for the perfect and imperfect FG plates with those available in the scientific literature. Effects due to material index, porosity factors, moisture and thermal loads, foundation rigidities, geometric ratios on the FG porous plate are all examined. Finally, this research will help us to design advanced functionally graded materials to ensure better durability and efficiency for hygro-thermal environments.