• 대한수학회보
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• 제54권3호
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• pp.967-973
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• 2017

We prove that a homogeneous square Einstein Finsler metric is either Riemannian or flat.

• Computers and Concrete
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• 제30권4호
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• pp.237-242
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• 2022

This paper is concerned with exponential stability in mean square for stochastic static neutral neural networks with varying delays. By using Lyapunov functional method and with the help of stochastic analysis technique, the sufficient conditions to guarantee the exponential stability in mean square for the neural networks are obtained and some results of related literature are extended.

• 한국전자거래학회:학술대회논문집
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• 한국전자거래학회 1998년도 학술대회지 vol.1
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• pp.255-268
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• 1998

$\square$ 정보기술 변화에 적극적 수용 및 대처 $\textbullet$ 다운사이징/라이트사이징 $\textbullet$ 분산 네트워크환경, 인터넷/인트라넷 $\textbullet$ 그룹웨어 ： 원활한 의사소통, 폭 넓은 정보공유, 신속한 의사결정 $\square$ 기업환경 변화에 적극적 수용 및 대처 $\textbullet$ Workflow： 경영혁신/프로세스 표준화 $\textbullet$ ERP: 기업 내부 업무의 전사적 통합 및 관리를 통한 경영 효율화 $\textbullet$ KMS: 지식의 정보화, 사람관리체제에서 지식관리 체제로 $\textbullet$ SCM: 제조에서 구매에 이르기까지 전 공급라인을 효율적으로 관리하여 재고를 최소화하고 비용을 최소화 $\textbullet$ CALS: 표준화를 통하여 기업간 거래를 효율화 $\square$ 정보시스템 환경의 변화 $\textbullet$ 정보기술혁신 + 기업환경 변화 =기업통합 (Electronic Collaboration) $\textbullet$ 복잡하고 다양해지는 요구 대처: 분산환경에서의 객체기술 $\square$ 기업 통합을 위한 응용시스템 $\textbullet$ 그룹웨어, ERP, SCM, PDM, KMS‥‥ $\textbullet$ 기업통합의 근간은 프로세스 설계 및 표준화 $\square$ 핸디＊솔루션 $\textbullet$ 기업 통합 (Electronic Collaboration) 정보시스템 도구 $\textbullet$ 분산 객체 모델 $\textbullet$ 워크플로우를 근간으로 한 SCM 지원의 정보시스템 개발 환경(중략)

• 대한전기학회논문지:시스템및제어부문D
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• 제50권7호
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• pp.350-353
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• 2001

In general, the Least Square Error method is used for signal classification to measure distance in the $l^2$ metric or the $L^2$ metric space. A defect of the Least Square Error method is that it does not classify properly some waveforms, which is due to the property of the Least Square Error method: the global analysis. This paper proposes a new linear operator, the Integra-Normalizer, that removes the problem. The Integra-Normalizer possesses excellent property that measures the degree of relative similarity between signals by expanding the functional space with removing the restriction on the functional space inherited by the Least Square Error method. The Integra-Normalizer shows superiority to the Least Square Error method in measuring the relative similarity among one dimensional waveforms.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.753-756
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• 2002

In this study, it is attempted to obtain the optimum size of holes in 15 square plate models where a hole exists on every quadrant of a plate, and to get eigenvalues by performing free vibration analysis far each model. Moreover, the specimen is produced from optimized square plate and eigenvalue of each plate is measured through the shocking load. And then the result is compared with that of finite element analysis. For free vibration analysis of the square plate, the boundary condition of finite element analysis and experiment is assumed as both ends support. From the results of this study, it is known that more stable structures can be designed by changing the natural frequency which is dependent on the location of holes and further studies are considered to be necessary for the basic design information.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.686-689
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• 2004

As the demands of X-Y linear motors increase, it becomes very important to measure flatness errors and to compensate them. In this study, in order to investigate flatness errors, a laser interferometer is used for measurement. To improve the measurement efficiency, a Union Jack method is adopted instead of a square method. The square method is frequently used because of its accuracy, but it requires many measurement points. In this study, the Union Jack method with Grey Theory is used. By using the Grey Theory, unmeasured data are predicted, and these are compared with results of the square method. The results show that the Union Jack method with Grey Theory is accurate enough to replace the square method.

• Nuclear Engineering and Technology
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• 제38권1호
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• pp.69-80
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• 2006

Fluid-elastic instability in an air-water two-phase cross-flow has been experimentally investigated using two different arrays of straight tube bundles: normal square (NS) array and rotated square (RS) array tube bundles with the same pitch-to-diameter ratio of 1.633. Experiments have been performed over wide ranges of mass flux and void fraction. The quantitative tube vibration displacement was measured using a pair of strain gages and the detailed orbit of the tube motion was analyzed from high-speed video recordings. The present study provides the flow pattern, detailed tube vibration response, damping ratio, hydrodynamic mass, and the fluid-elastic instability for each tube bundle. Tube vibration characteristics of the RS array tube bundle in the two-phase flow condition were quite different from those of the NS array tube bundle with respect to the vortex shedding induced vibration and the shape of the oval orbit of the tube motion at the fluid-elastic instability as well as the fluid-elastic instability constant.

• Journal of electromagnetic engineering and science
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• 제18권4호
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• pp.215-220
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• 2018

This study presents a dual-band polarization-reconfigurable antenna that comprises a large square patch with a pair of corner-cut edges and two small square patches with a shorting via. Two PIN diodes are located between the large square patch and two small square patches. Depending on the bias state applied to the two PIN diodes, each small patch may be disconnected or connected to the large square patch. As a result, the proposed antenna can provide polarization reconfigurability between two orthogonal linear polarizations. Further, the proposed antenna operates at 2.51 GHz and 2.71 GHz. From the measured results, the proposed antenna shows a 10 dB bandwidth of 2.39% (2.49-2.55 GHz) and 2.58% (2.68-2.75 GHz). In this work, the frequency ratio can be easily controlled by changing the size of the small patch.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2005년도 추계 학술대회논문집
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• pp.81-85
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• 2005

Three-dimensional steady incompressible laminar entry flows in a square duct of $90^{\circ}$ bend are numerically simulated by a new solution code(PowerCFD) using unstructured cell-centered method. Solutions are obtained with three unstructured grid types of hexahedron, prism and hybrid at a Reynolds number, based on the hydraulic diameter and bulk velocity, of 790. Interesting features of the flow are presented in detail. Detailed comparisons between the computed solutions and the available experimental data are given mainly for the velocity distributions at cross-sections in a $90^{\circ}$ bend of a square duct with fully-developed entry flows. It is found that the code is capable of producing the nature of laminar flow in curved square duct with no grid type dependency.

• 한국정밀공학회지
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• 제16권2호통권95호
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• pp.31-38
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• 1999

Square cups have been drawn to 20mm~60mm in depth and displacements and strains have been analysed by FEM and experiment. Displacements and strains on the corner flange of square cups have been compared with those of cylindrical cups. The results have shown that shear strains take place on corner flanges of square cups, it is necessary to adopt effective strain for comparing of stains and the effective strains on the corner flange in square cups are smaller than those in cylindrical ones.