• 한국CDE학회논문집
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• 제16권2호
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• pp.126-136
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• 2011

The existing approaches to freeform building construction cause many problems. However, recent BIM technique development based on parametric modeling method and improvement of freeform materials manufacturing technology using IT technology encouraged many advanced countries to try experimental projects. Thus, laser scanning technique is in the limelight as a new alternative in the field of freeform building construction and inspection. This study selected a domestic small freeform building and practiced laser scanning and as-planned modeling by using Reverse Engineering. Then each deviation was comparatively analyzed through figures which extracted data by numerically analyzing the newly modeled as-built and Excel spread sheet. Through the process, limits and follow-up research subjects are discussed as well.

• Journal of Microbiology and Biotechnology
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• 제22권6호
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• pp.788-792
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• 2012

We report the computational structural simulation of the Cry1Ab19 toxin molecule from B. thuringiensis BtX-2 based on the structure of Cry1Aa1 deduced by x-ray diffraction. Validation results showed that 93.5% of modeled residues are folded in a favorable orientation with a total energy Z-score of -8.32, and the constructed model has an RMSD of only $1.13{\AA}$. The major differences in the presented model are longer loop lengths and shortened sheet components. The overall result supports the hierarchical three-domain structural hypothesis of Cry toxins and will help in better understanding the structural variation within the Cry toxin family along with facilitating the design of domain-swapping experiments aimed at improving the toxicity of native toxins.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.173-174
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• 2006

High power amplifier (HPA), which is used in transmitter of wireless communication systems, usually works in near saturation point in order to achieve maximum efficiency. In this region, HPA can introduce undesirable nonlinear effects. In this paper, we present a polynomial modeling method for efficient techniques to compensate for nonlinear distortion introduced by nonlinear HPA. Proposed polynomial predistorter inverses actual amplifier. Namely, we derive polynomials of amplifiers from analytical method and the electrical parameters in the data sheet of an actual amplifier and then can derive polynomial predistorter by inversing them. It is an effective and a simple method to compensate nonlinear distortion. SSPA(Solid-state power amplifier) is considered. We also analyze the effects of predistortion on the SER performance of communication system with 16-QAM modulation format. The results have shown the efficiency of this model.

• Journal of information and communication convergence engineering
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• 제9권1호
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• pp.74-77
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• 2011

PSPICE modeling of a commercial LED driver IC (TOP245P) and PC817A optocoupler is proposed for the switch-mode power supply (SMPS) (applicable to LED driver) design and simulation. An analog behavioral model of the TOP245P IC including the shunt regulator, under-voltage(UV) detection, over-voltage(OV) shut-down and SR flip-flop is developed by using PSPICE. The empirical equation of PC817A current transfer ratio (CTR) is fitted from the datasheet of PC817A. Two types of SMPSs are simulated with the averaged-model and switching-model. The simulation results by the proposed PSPICE models are in good agreement with those in the data sheet and an experimental data.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 금형가공,미세가공,플라스틱가공 공동 심포지엄
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• pp.23-28
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• 2005

Microlens arrays were fabricated using a modified LIGA process based on the exposure of a PMMA (Polymethylmethacrylate) sheet to deep x-rays and subsequent thermal treatment. A successful modeling and analyses for microlens formation were presented according to the experimental procedure. A nickel mold insert was fabricated by the nickel electroforming process on the PMMA microlens arrays fabricated by the modified LIGA process. For the replication of microlens arrays having various diameters with different foci on the same substrate, the hot embossing and the microinjection molding processes have been successfully utilized with the fabricated mold insert. Fabricated microlenses showed good surface roughness than the mold insert. The focal lengths of the injection molded microlenses were successfully measured experimentally and also estimated theoretically.

• 소성∙가공
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• 제11권6호
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• pp.482-486
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• 2002

Sandwich sheets composed of stainless steel/aluminum/stainless steel were produced by roll cladding. In order to investigate the effect of the friction between roll and cladding sample, the lubrication condition of the roll surface was varied. Clad rolling without lubrication gave rise to a small increment of the normal strain of aluminum in the rolling direction. This experimental result was confirmed by FEM modeling. Through-thickness hardness gradients in the mid aluminum layer was successfully explained by variations of the strain state through thickness layers. FEM modeling implied that cladding without lubrication led to a large shear strain variation at the surface of aluminum layer.

• Computers and Concrete
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• 제29권4호
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• pp.219-235
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• 2022

Strengthening slender reinforced concrete (RC) columns is a challenge. They are susceptible to overall buckling that induces bending moment and axial compression. This study presents the precise three-dimensional finite element modeling of slender RC columns strengthened with fiber-reinforced polymer (FRP) composites sheets with various patterns under concentric or eccentric compression. The slenderness ratio λ (height/width ratio) of the studied columns ranged from 15 to 35. First, to determine the optimal modeling procedure, nine alternative nonlinear finite element models were presented to simulate the experimental behavior of seven FRP-strengthened slender RC columns under eccentric compression. The models simulated concrete behavior under compression and tension, FRP laminate sheets with different fiber orientations, crack propagation, FRP-concrete interface, and eccentric compression. Then, the validated modeling procedure was applied to simulate 58 FRP-strengthened slender RC columns under compression with minor eccentricity to represent the inevitable geometric imperfections. The simulated columns showed two cross sections (square and rectangular), variable λ values (15, 22, and 35), and four strengthening patterns for FRP sheet layers (hoop H, longitudinal L, partial longitudinal L_w, and longitudinal coupled with hoop LH). For λ=15-22, pattern L showed the highest strengthening effectiveness, pattern L_w showed brittle failure, steel reinforcement bars exhibited compressive yielding, ties exhibited tensile yielding, and concrete failed under compression. For λ>22, pattern L_w outperformed pattern L in terms of the strengthening effectiveness relative to equivalent weight of FRP layers, steel reinforcement bars exhibited crossover tensile strain, and concrete failed under tension. Patterns H and LH (compared with pattern L) showed minor strengthening effectiveness.

• 한국태양에너지학회 논문집
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• 제23권3호
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• pp.37-44
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• 2003

This paper presents the modeling and analysis of V47-660 kW wind turbine generation system(WTGS) in Jeju wind farm using Psim program. Generally, WTGS is composed of complicated machinery. So it is very difficult to present the mathematic model. This means that WTGS has a nonlinear system. Using the real output data from V47 WTGS for one year, it is simply possible to express the rotor and gear coupling system as a torque generator according to wind speed. Also, the modeling of electrical system can be able to present using the data sheet from the company. To analyze the proposed method, results of computer simulation using Psim program are presented to support the discussion.

• 한국BIM학회 논문집
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• 제1권2호
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• pp.6-11
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• 2011

국내 토목분야의 건설 산업은 비효율적인 의사소통으로 인하여 업무전환단계에서의 정보 누락 및 그로 인한 비용손실 등의 문제점이 발생한다. 이러한 문제점에 대한 해결책으로 BIM의 도입이 대두되고 있다. BIM은 구조물의 생애주기 전 단계에서 발생되는 모든 정보들을 3차원 파라메트릭 CAD와 연계된 3차원 정보모델을 통하여 관리하여 정보 활용의 효율성을 극대화 시킨다. 본 논문에서는 BIM기반의 교량 건설 프로젝트의 구조설계업무에서 사용할 목적으로 3차원 정보모델을 활용한 교량의 구조설계 프로세스를 제안하였다. 제안된 프로세스는 구조설계업무를 통하여 결정되는 정보들을 활용하여 3차원 정보 모델링작업이 이루어질 수 있도록 구성하였다. 또한 제시된 프로세스를 활용하여 현재 건설이 진행 중인 스틸박스 교량의 상부구조를 대상으로 구조설계의 최종 산출물인 구조계산서를 구축된 BIM기반의 구조설계 프로세스를 활용하여 도출할 수 있도록 구성하였다.

• 한국물환경학회지
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• 제26권4호
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• pp.637-647
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• 2010

The Universal Soil Loss Equation (USLE)-based modeling systems have been widely used to simulate soil erosion studies. However the GIS-based USLE modeling systems have limitation in gully erosion evaluation which is one of the most important factor in soil erosion estimation. In this study, the integrated soil erosion evaluation system using with Sediment Assessment Tool for Effective Erosion Control (SATEEC) system, nLS and Unit Stream Power-based Erosion/Deposition (USPED) model was developed to simulate gully erosion. Gully head location using nLS model, USPED for gully erosion, and the SATEEC estimated sheet and rill erosion were evaluated and combined together with the integrated soil erosion evaluation system. This system was applied to the Haean-myeon watershed, annual average sediment-yield considering sheet, rill and gully erosion was simulated as 101,933 ton/year at the study watershed. if the integrated soil erosion evaluation system is calibrated and validated with the measured data, this system could be efficiently used in developing site-specific soil erosion best management system to reduce soil erosion and muddy water inflow into the receiving waterbody.