• Journal of the Computational Structural Engineering Institute of Korea
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• v.15 no.2
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• pp.351-365
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• 2002

The box system that is composed only of reinforced concrete walls and slabs we adopted on many high-rise apartment buildings recently constructed in Korea. And the framed structure with shear wall core that can effectively resist horizontal forces is frequently adopted for the structural system for high-rise building structures. In these structures, a shear wall may have one or more openings for functional reasons. It is necessary to use subdivided finite elements for accurate analysis of the shear wall with openings. But it would take significant amount of computational time and memory if the entire building structure is subdivided into a finer mesh. An efficient analysis method that can be used regardless of the number, size and location of openings is proposed in this study. The analysis method uses super element, substructure, matrix condensation technique and fictitious beam technique. Three-dimensional analyses of the box system and the framed structure with shear wall core having various types of openings were performed to verify the efficiency of the proposed method. It was confirmed that the proposed method have outstanding accuracy with drastically reduced time and computer memory from the analyses of example structures.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.15 no.2
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• pp.237-249
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• 2002

The wall system that is composed only of reinforced concrete walls and slabs is adopted on many high-rise apartment buildings recently constructed. In the apartment buildings, a shear wall may have one or mote openings for functional reasons. Many researches on the analysis of shear wall with openings were performed. But, some restrictions prevent those research results being applied to practical analysis and design procedure. It is necessary to use subdivided finite elements lot accurate analysis of the wall system with openings. But it would cost tremendous amount of analysis time and computer memory if the entire building structure is subdivided into a finer mesh. An efficient analysis method which can be used regardless of the number, size and location of openings is proposed in this study. The analysis method uses super element, matrix condensation technique and fictitious beam technique. Analyses of example structures having various types of openings were performed to verify the efficiency of proposed method. It was confirmed that the proposed method have outstanding accuracy with drastically reduced time and computer memory from the analyses of example structures.

• Journal of the Institute of Convergence Signal Processing
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• v.9 no.3
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• pp.201-207
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• 2008

This paper presents the implementation of a Tiling System about Preprocessing functions of JPEG 2000. The system covers the JPEG 2000 standard and is designed to determine the size of the image, to expand the image area and to split input image into several tiles. In order to split the input image with the progressive transmission into several tiles and transmit a tile of this image to others, this system store this image into Frame Memory. Therefore, this is designed as the Finite State Machine (FSM) to sequence through specific patterns of states in a predetermined sequential manner by using Verilog-HDL and be designed to handle a maximum 5M image. Moreover, for identifying image size for expansion, we propose several formula which are based on remainder after division (rem). we propose the true table which determines the size of the image input patterns by using results of these formula. Under the condition of TSMC 0.25um ASIC library, gate count is 18,725 and maximum data arrival time is 18.94 [ns].

• Structural Engineering and Mechanics
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• v.74 no.1
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• pp.129-143
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• 2020

This study proposes a new shape memory alloy-tuned mass damper (SMA-TMD) and investigates the effectiveness of this damper in reducing and controlling the vibrations of a transmission tower-line system under various seismic excitations. Based on a practical transmission line system and considering the geometric nonlinearity of this system, the finite element (FE) software ANSYS is used to create an FE model of the transmission tower-line system and simulate the proposed SMA-TMD. Additionally, the parameters of the SMA springs are optimized. The effectiveness of a conventional TMD and the proposed SMA-TMD in reducing and controlling the vibrations of the transmission tower-line system under seismic excitations is investigated. Moreover, the effects of the ground motion intensity and frequency ratio on the reduction ratio (η) of the SMA-TMD are studied. The vibration reduction effect of the SMA-TMD under various seismic excitations is superior to that of the conventional TMD. Changes in the ground motion intensity and frequency ratio have a significant impact on the η of the SMA-TMD. As the ground motion intensity and frequency ratio increase, the η values of the SMA-TMD first increase and then decrease. Studying the vibration reduction effects of the SMA-TMD can provide a reference for the practical engineering application of this damper.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.7 s.337
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• pp.27-34
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• 2005

Iterative detection (ID) has proven to be a near-optimal solution for concatenated Finite State Machines (FSMs) with interleavers over an additive white Gaussian noise (AWGN) channel. When perfect channel state information (CSI) is not available at the receiver, an adaptive ID (AID) scheme is required to deal with the unknown, and possibly time-varying parameters. The basic building block for ID or AID is the soft-input soft-output (SISO) or adaptive SISO (A-SISO) module. In this paper, Reduced State SISO (RS-SISO) algorithms have been applied for complexity reduction of the A-SISO module. We show that serially concatenated CPM (SCCPM) with AID has turbo-like performance over fading ISI channels and also RS-A-SISO systems have large iteration gains. Various design options for RS-A-SISO algorithms are evaluated. Recently developed density evolution technique is used to analyze RS-A-SISO algorithms. We show that density evolution technique that is usually used for AWGN systems is also a good analysis tool for RS-A-SISO systems over frequency-selective fading channels.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.3
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• pp.429-438
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• 1994

Three-dimensional analyses of multistory structures with wings using finite element models require tedious input data preparation, longer computation time. and larger computer memory. So this study lays emphasis on the development of efficient analysis models for a three-dimensional multistory structure with wings, including in-plane deformation of floor slabs. Since a three-dimensional multistory structure with wings is regarded as a combination of wing structures and their junction in this study, the proposed analysis models are easily applicable to multistory structures with plans in the shape of letters Y, U, H, etc. Dynamic analyses results obtained using proposed models are in excellent agreement to those acquired using three-dimensional finite element models in terms of natural vibration periods, mode shapes and displacement time history.

• Journal of IKEEE
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• v.22 no.3
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• pp.522-531
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• 2018

A public-key cryptography processor EC-RSA was designed, which integrates a 224-bit prime field elliptic curve cryptography (ECC) defined in the FIPS 186-2 as well as RSA with 2048-bit key length into a single hardware structure. A finite field arithmetic core used in both scalar multiplication for ECC and exponentiation for RSA was designed with 32-bit data-path. A lightweight implementation was achieved by an efficient hardware sharing of the finite field arithmetic core and internal memory for ECC and RSA operations. The EC-RSA processor was verified by FPGA implementation. It occupied 11,779 gate equivalents (GEs) and 14 kbit RAM synthesized with a 180-nm CMOS cell library and the estimated maximum clock frequency was 133 MHz. It takes 867,746 clock cycles for ECC scalar multiplication resulting in the estimated throughput of 34.3 kbps, and takes 26,149,013 clock cycles for RSA decryption resulting in the estimated throughput of 10.4 kbps.

• Journal of IKEEE
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• v.24 no.1
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• pp.1-8
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• 2020

In this paper, a semi-infinite array analysis method is proposed to analyze the defects that may occur during the fabrication of the frequency selective radome. In the analysis of N×N finite array structure using 3D analysis software, much analysis time and memory are required, whereas the semi-infinite array structure analysis proposed in this paper can predict relatively accurate electromagnetic performance while reducing the analysis time. In comparison with the results of the periodic simulation, the simulation of the semi-infinite array structure confirmed the error within ±3%. To verify the results of the simulation, the results were compared with the measured results, and the same tendency at the point of performance change and similar performance degradation at the band of interest were investigated. Using the proposed semi infinite array structure analysis, it is confirmed that the analysis of defects in the electromagnetic periodic structure is possible.

• Structural Engineering and Mechanics
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• v.21 no.6
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• pp.713-735
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• 2005

Due to the complexity of mathematical expressions, the literature concerning the free vibration analysis of plates carrying multiple three-degree-of-freedom (dof) spring-mass systems is rare. In this paper, the three degrees of freedom (dof's) for a spring-mass system refer to the translational motion of its lumped mass in the vertical ($\bar{z}$) direction and the two pitching motions of its lumped mass about the two horizontal ($\bar{x}$ and $\bar{y}$) axes. The basic concept of this paper is to replace each three-dof spring-mass system by a set of equivalent springs, so that the free vibration characteristics of a rectangular plate carrying any number of three-dof spring-mass systems can be obtained from those of the same plate supported by the same number of sets of equivalent springs. Since the three dof's of the lumped mass for each three-dof spring-mass system are eliminated to yield a set of equivalent springs, the total dof of the entire vibrating system is not affected by the total number of the spring-mass systems attached to the rectangular plate. However, this is not true in the conventional finite element method (FEM), where the total dof of the entire vibrating system increases three if one more three-dof spring-mass system is attached to the rectangular plate. Hence, the computer storage memory required by using the presented equivalent spring method (ESM) is less than that required by the conventional FEM, and the more the total number of the three-dof spring-mass systems attached to the plate, the more the advantage of the ESM. In addition, since manufacturing a spring with the specified stiffness is much easier than making a three-dof spring-mass system with the specified spring constants and mass magnitude, the presented theory of replacing a three-dof spring-mass system by a set of equivalent springs will be also significant from this viewpoint.

• Nuclear Engineering and Technology
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• v.52 no.10
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• pp.2162-2172
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• 2020

Due to its computational efficiency and geometrical flexibility, the Method of Characteristics (MOC) has been widely used for light water reactor lattice physics analysis. Usually acceleration methods are necessary for MOC to achieve acceptable convergence on practical reactor physics problems. Among them, Coarse Mesh Finite Difference (CMFD) is very popular and can drastically reduce the number of transport iterations. In OpenMOC, CMFD acceleration was implemented but had the limitation of supporting only a uniform CMFD mesh, which would often lead to splitting MOC source regions, thus creating an unnecessary increase in computation and memory use. In this study, CMFD acceleration with a non-uniform Cartesian mesh is implemented into OpenMOC. We also propose a quadratic fit based CMFD prolongation method in the axial direction to further improve the acceleration when multiple MOC source regions are contained in one CMFD coarse mesh. Numerical results are presented to demonstrate the improvement of the CMFD acceleration capability in OpenMOC in terms of both efficiency and stability.