• 전자공학회논문지CI
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• 제38권6호
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• pp.93-105
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• 2001

격자 벡터 양자화의 비 손실 과정에서는 생성된 코드단어들을 radius 열과 Index 열로 열거한다. radius 열은 run-length 부호화한 한 다음 Entropy 부호화한다. 또한 index 열들은 이진의 고정길이로 표현한다. 비트율이 증가함에 따라 index 비트는 선형적으로 증가하여서 부호화 성능을 감소시킨다. 이 논문에서는, 넓은 비트율의 범위에서 index 비트를 줄이기 위해서, set partitioning 방식을 채택한 새로운 열거 알고리즘을 개발하였다. 제안된 열거 방법은 큰 index 값을 작은 값들을 천이 시켜서 index 비트를 줄인다. 제안된 비손실 기법을 웨이블릿 기반의 영상 부호화에 적용시켰을 때, 0.3 bits/pixel 이상의 비트룰에서 기존의 비손실 부호화 방식보다 10%이상의 비트율을 감소시켰다.

• 대한전자공학회논문지
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• 제20권4호
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• pp.10-15
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• 1983

본 논문에서는 전송 속도가 9600 bps인 data modem의 복조기와 equalizer의 효과적인 구성에 대하여 연구하였으며, finite word length 효과가 equalizer 동작에 미치는 영향을 제시하였다. 복조기에는 tap수가 37개인 decimation filter를 사용해서 symbol당 곱셈 횟수를 크게 줄였는데 이때 equalizer 동작에 있어 충분한 결과를 얻을 수 있음을 알 수 있었다. 주파수 offset이 존재할 때 1차 반송파 위상 추적 loop와 2차 반공파 위상 추적 loop의 성능을 비교하였고, word length를 각각 8 bit, 12 bit 및 16bit로 변화시켰을 경우 equalizer 평형상태 MSE(mean square error)의 변화 및 tap 적응을 위한 최적 step see와 lap수를 제시하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.211-211
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• 2012

Using spin-polarized density-functional theory calculations, we find that the existence of either Peierls instability or antiferromagnetic spin ordering is sensitive to hydrogen passivation near the step. As hydrogens are covered on the terrace, the dangling bond electrons are localized at the step, leading to step-induced states. We investigate the competition between charge and spin orderings in dangling-bond (DB) wires of increasing lengths fabricated on an H-terminated vicinal Si(001) surface. We find antiferromagnetic (AF) ordering to be energetically much more favorable than charge ordering. The energy preference of AF ordering shrinks in an oscillatory way as the wire length increases. This oscillatory behavior can be interpreted in terms of quantum size effects as the DB electrons fill discrete quantum levels.

• 에너지공학
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• 제24권2호
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• pp.110-114
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• 2015

A numerical investigation has been carried out on recirculation zone formed downstream of a compressible flow over a backward facing step. The study has been performed by solving Two-Dimensional Navier-Stokes equations. The system of governing equations has been solved, using an explicit Harten-Yee Non- MUSCL Modified flux type TVD scheme and a zero-equation algebraic turbulence model to calculate the eddy viscosity coefficient. The recirculation region dimensions are characterized over a range of Mach numbers of fixed step height 5mmThe detail of recirculation zone such as pressure, temperature, recirculation length, strength etc are reported. The variations of these characteristics due to change of Mach number are also presented.

• 한국분무공학회지
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• 제17권1호
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• pp.27-34
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• 2012

In this paper an experimental study is presented to investigate the effect of a step edge and a stationary droplet on the dynamic behavior of impacting droplet on a wall. The main parameters are the distance from the edge and the center-to-center distance between two droplets. Photographic images are presented to show coalescence dynamics, shape evolution and contact line movement. The emphasis is on presenting the spreading length of droplet for the step edge and two coalescing droplets along their original centers. It is clarified that the droplet exhibits much different dynamic behavior depending on the location of the step edge. The momentum of impacting droplet was better transferred to the stationary droplet as the center- to-center distance between two droplets was reduced, which results in more spreading of coalescing droplet.

• Structural Engineering and Mechanics
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• 제17권6호
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• pp.735-749
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• 2004

This work presents a direct integration scheme, based on a fourth order finite difference approach, for elastodynamics. The proposed scheme was chosen as an alternative for attenuating the errors due to the use of the central difference method, mainly when the time-step length approaches the critical time-step. In addition to eliminating the spurious numerical oscillations, the fourth order finite difference scheme keeps the advantages of the central difference method: reduced computer storage and no requirement of factorisation of the effective stiffness matrix in the step-by-step solution. A study concerning the stability of the fourth order finite difference scheme is presented. The Finite Element Method and the Boundary Element Method are employed to solve elastodynamic problems. In order to verify the accuracy of the proposed scheme, two examples are presented and discussed at the end of this work.

• 현장농수산연구지
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• 제12권1호
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• pp.21-27
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• 2010

The objective of this study was to determine the effects of "Green-one" organic nutrient on mycelial growth and fruiting of P. ostreatus. The dilution concentrations of "Green-one" was treated as follows. There was control, 100, 200, 400 concentrations. That treatments were treated with step of each mycelial growth step. The best of growth steps was mycelial scratching step. At that time, DPI(Day required for primordial formation after inoculation) was shortened for 1 day. Valid germination stipe are 15 pieces, 3 pieces more than control. Stipe length and stipe diameter was long each 4mm, 3mm more than control. Pileus size is shortened than control. Yields per one bottle(g/850cc) was 146g increased 6.5% than control 137g/850cc.

• Computers and Concrete
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• 제7권5호
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• pp.437-453
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• 2010

CFRP has been widely used for strengthening reinforced concrete members in last decade. The strain transfer mechanism from concrete face to CFRP is a key factor for rigidity, ductility, energy dissipation and failure modes of concrete members. For these reasons, determination of the effective CFRP bonding length is the most crucial step to achieve effective and economical strengthening. In this paper, generalizations are made on effective bonding length by increasing the amount of test data. For this purpose, ANSYS software is employed, and an experimentally verified nonlinear finite element model is prepared. Special contact elements are utilized along the concrete-CFRP strip interface for investigating stress distribution, load-displacement behavior, and effective bonding length. Then results are compared with the experimental results. The finite element model found consistent results with the experimental findings.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(4)
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• pp.215-218
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• 2000

This paper describes a new algorithm for segmenting continuous handwritten signatures sampled by a digitizer. Signatures are segmented by three procedures. The first step is to calculate the pen tip speed. Then the Gabor wavelet is carried out on the acquired data from the first step. Finally, the local minima of the filtered output are selected as segmentation points of the signature. The proposed method is experimented with numerous signatures with various length and complexity.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1995년도 추계학술대회논문집
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• pp.128-135
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• 1995

Theoretical and experimental drawing characteristics for the step drawbead are discussed. The drawbead restraining forces and strains by the varous drawing angles are measured experimentally. Also, during the blank holding process, the strain distributions of upper and lower skins of specimens are analysed by the 2-D rigid-plastic F.E.M And the drawbead restraining forces and strain distributions for the drawn specimens by the drawing length are obtained by experiment.