• 한국진공학회지
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• 제1권1호
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• pp.60-66
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• 1992

초격자와 다양자우물이 가질 수 있는 모든 구조에 대한 subband와 입자의 envelope 파동함수를 계산할 수 있는 방법을 제시하고 단순조성 초격자와 $\delta$-dopping 초격 자에 적용한 결과를 다른 방법의 계산결과와 비교하여 그 타당성을 검토하였다. 나아가서 기존의 방법에서 요구되었던 일정한 유효질량의 가정없이 graded gap 초격자에 적용하여 입자의 유효질량의 연속변화에 따른 subband 에너지와 파동함수를 계산하였다.

• 패션비즈니스
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• 제10권3호
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• pp.129-142
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• 2006

This research chose 135 environmental cleaners in Busan Metropolitan City as subjects. First, the reality of wearing their safety jackets was investigated. Next, visual evaluation of the reflexive function of the current safety jackets was made. Then, based on the above results and the subsequent improvement proposal, the final product, the research costume, was made. 1. Based on the investigation of the wearing reality of safety jackets and the visual evaluation results of the reflexive function, an improvement proposal was made. As cleaners are usually seen sidewise on the roads and lateral luminosity is rather low, this aspect was compensated on the part of a jacket. Also, the reflexive belt used the diagram of ${\Delta}$ to improve visual effects. 2. As the lower body held the accident frequency of 45.0%, the sides of pants had the reflexive belt to increase visibility. 3. In consideration of the mutual effects between the background cloth and general reflexive width, the same width (5cm) of the reflexive belt as that of Type A was adopted.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제12권1호
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• pp.13-23
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• 2008

In [7, 8], they proposed a new singular function(NSF) method to compute singular solutions of Poisson equations on a polygonal domain with re-entrant angles. Singularities are eliminated and only the regular part of the solution that is in $H^2$ is computed. The stress intensity factor and the solution can be computed as a post processing step. This method was extended to the interface problem and Poisson equations with the mixed boundary condition. In this paper, we give NSF method for the Helmholtz equations ${\Delta}u+Ku=f$ with homogeneous Dirichlet boundary condition. Examples with a singular point are given with numerical results.

• Journal of Electrical Engineering and information Science
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• 제2권3호
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• pp.14-21
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• 1997

In delay-optimized designs, timing failures due to manufacturing delay defects are more likely to occur because the average timing slacks of paths decrease and the system becomes more sensitive to smaller delay defect sizes. In this paper, the impact of delay optimized logic circuits on delay fault testing will be discussed and compared to the case for non-optimized designs. First, we provide a timing optimization procedure and show that the resultant density function of path delays is a delta function. Next we also discuss the impact of timing optimization on the yield of a manufacturing process and the defect level for delay faults. Finally, we will give some recommendations on the determination of the system clock time so that the delay-optimized design will have the same manufacturing yield as the non-optimized design and on the determination of delay fault coverage in the delay-optimized design in order to have the same defect-level for delay faults as the non-optimized design, while the system clock time is the same for both designs.

• 한국컴퓨터정보학회논문지
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• 제4권4호
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• pp.133-139
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• 1999

본 논문은 현재 사용되고 있는 케이블의 진단을 위해서 열화가중치라는 새로운 접근법을 사용하였다. 케이블은 상시에 높은 온도로 운전된다는 점, 수분이 접촉할 확률이 크다는 점에서 신뢰성 있고 효율적인 열화진단은 필수적이라고 할 수 있다. 종래의 연구는 수트리가 발생되는 절연층을 주 대상으로 삼았으나, 현대에 와서는 절연층뿐만 아니라, 내·외부 반도전층 또한 활발한 연구가 이루어지고 있다. 본 연구에서는 최근에 국내에서 제안된 열화가중치법을 이용하여 케이블의 열화인자가 될 수 있는 부분에 대하여 특성분석을 수행한 다음, 열화가중치를 부여하여 케이블의 최종적인 상태를 파악해 보았다.

• Structural Engineering and Mechanics
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• 제15권5호
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• pp.535-550
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• 2003

In this paper, a boundary-type meshfree method, the boundary radial point interpolation method (BRPIM), is presented for solving boundary value problems of two-dimensional solid mechanics. In the BRPIM, the boundary of a problem domain is represented by a set of properly scattered nodes. A technique is proposed to construct shape functions using radial functions as basis functions. The shape functions so formulated are proven to possess both delta function property and partitions of unity property. Boundary conditions can be easily implemented as in the conventional Boundary Element Method (BEM). The Boundary Integral Equation (BIE) for 2-D elastostatics is discretized using the radial basis point interpolation. Some important parameters on the performance of the BRPIM are investigated thoroughly. Validity and efficiency of the present BRPIM are demonstrated through a number of numerical examples.

• 한국기계연구소 소보
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• 통권19호
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• pp.93-115
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• 1989

Cerebellar Model Arithmetic Controller(CMAC) has been introduced as an adaptive control function generator. CMAC computes control functions referring to a distributed memory table storing functional values rather than by solving equations analytically or numerically. CMAC has a unique mapping structure as a coarse coding and supervisory delta-rule learning property. In this paper, learning aspects and a convergence of the CMAC were investigated. The efficient training algorithms were developed to overcome the limitations caused by the conventional maximum error correction training and to eliminate the accumulated learning error caused by a sequential node training. A nonlinear function generator and a motion generator for a two d. o. f. manipulator were simulated. The efficiency of the various learning algorithms was demonstrated through the cpu time used and the convergence of the rms and maximum errors accumulated during a learning process; A generalization property and a learning effect due to the various gains were simulated. A uniform quantizing method was applied to cope with various ranges of input variables efficiently.

• 한국국방경영분석학회지
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• 제12권1호
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• pp.106-121
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• 1986

In this study, estimators which shrink towards other than the origin are developed. We discuss the harmonic mean of the observations as a reasonable center and develop estimators which shrink the MLE(${\delta}^{\circ}$) towards the harmonic mean under the loss function $L_1$. The percentage reduction of average loss(PRAL) of derived estimators compared to the usual estimator(MLE) under the loss function $L_1$ is estimated for p=4 and 8. Computer simulation shows that the risk performance of the derived estiamtors is remarkably good when the means are greater than three.

• 한국소음진동공학회논문집
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• 제12권2호
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• pp.97-107
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• 2002

The continuous circular cylindrical shells are widely used for the high performance structures of aircraft, spacecraft, missile, nuclear fuel rod shell and so on. In this paper, a method for the vibrational analysis of the continuous circular cylindrical shells with the clamped-clamped supports at two end edges is developed by using the modal expansion method. Forces and/or moments acting on the shell surface are expressed in terms of the Dirac Delta Function. Frequency equation of the continuous shell is also derided by the application of the equilibrium of forces and the continuity of displacements at the boundary. Natural frequencies of the continuous shell are calculated numerically with mathematica 3.0 and they are compared with FEM results from the ANSYS 5.3 to improve the reliability of analytic solutions. Mode shares obtained by the FEM are Presented in this paper.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1998년도 춘계학술대회 논문집
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• pp.163-166
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• 1998

In this paper, breakdown strength and dielectric characteristics were experimented in the structures of insulation/insulation/insulation and insulation/semiconductor/insulation by using of insulation material of polyethylene terephthalate film. The breakdown strength and the permitivity of each specimen were measured as a function of temperature and frequency respectively. The breakdown strength of PET/PET/PET did not changed greatly but that of PET/SEMl/PEr increased as a function of temperature. As the frequency inclosed, the permitivity of PET/PET/PET and PET/SEMI/PET decreased. The tan $\delta$ of PET/PET/PET showed lower than that of PET/SEMl/PET in low frequency but higher in high frequency .