• Journal of Communications and Networks
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• v.12 no.2
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• pp.191-197
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• 2010

In this paper, we propose a novel methodology to identify border gateway protocol (BGP) updates associated with major events - affecting network reachability to multiple ASes - and separate them (statistically) from those attributable to minor events, which individually generate few updates, but collectively form the persistent background noise observed at BGP vantage points. Our methodology is based on principal component analysis, which enables us to transform and reduce the BGP updates into different AS clusters that are likely affected by distinct major events. We demonstrate the accuracy and effectiveness of our methodology through simulations and real BGP data.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.04a
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• pp.315-320
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• 2001

Ultra-abrasives such as diamond and CBN have used to maintain accuracy and form deviation for superalloy etc. This study contains the dry cylindrical grinding of metals with Vitrified-bond CBN wheel and Resinoid-bond CBN wheel. For various condition of grinding speed, workpiece speed, grinding depth and feed speed of table, the grinding resistance, the surface roughness, and material removal are measured and discussed.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.04a
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• pp.193-196
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• 2000

In the turbine-blade manufacturing industry, turbine-blades are machined and then are assembled to form a circular roll of blades. The roll of blades should be balanced as much as possible, since otherwise the efficiency of the turbine generator might degrade. We propose a heuristic method for balancing blades based on the number partitioning algorithm. The proposed method outperformed existing methods remarkably in terms of the accuracy with a negligible increase in the running time.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.993-997
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• 1997

The continuous chip depresses the accuracy of workpieces and promotes the wear of machine tools and hunts operators. So chip control os a major problem in turning process. In this paper, a method of chip identification is develope by pyrometer. The identifier is applied in real-time control of chip pattern with adjusting feedrate.

• Journal of applied mathematics & informatics
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• v.19 no.1_2
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• pp.415-425
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• 2005

This paper outlines a reliable strategy for solving nonlinear Volterra-Fredholm integro-differential equations. The modified form of Adomian decomposition method is found to be fast and accurate. Numerical examples are presented to illustrate the accuracy of the method.

• Journal of applied mathematics & informatics
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• v.14 no.1_2
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• pp.365-376
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• 2004

The purpose of this study is to show that the accuracy of the interpolation method can be at least doubled when additional smoothness requirements and boundary conditions are met. In particular, as a basis function, we are interested in using a conditionally positive definite function $\Phi$ whose generalized Fourier transform is of the form $\Phi(\theta)\;=\;F(\theta)$\mid$\theta$\mid$^{-2m}$ with a bounded function F > 0.

• Journal of Magnetics
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• v.13 no.4
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• pp.136-139
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• 2008

A simplified equation of depinning fields from notches of ferromagnetic Permalloy nanowires is presented. The derived equation is given in the form of an explicit function of nanowire width and thickness, and notch depth and angle. The equation agrees with all micromagnetic simulation results to an accuracy of ${\pm}$ 0.5 mT.

• Proceedings of the KIEE Conference
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• 1997.07c
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• pp.1177-1179
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• 1997

In this paper, short-term power demand forecast using exclusion of week periodicity presented. Week periodicity excluded from weekday change ratio. Forecast term of five and multiple regression model of the three form was composed. Forecast result was good. Therefore, It Could be the power demand forecast of special day(weekend). This method may contribute improvement of forecast accuracy.

• Journal of the Korean Data and Information Science Society
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• v.15 no.2
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• pp.423-430
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• 2004

We provide the exact form of a Rao-Robson version of the chi-squared test of multivariate normality suggested by Park(2001). This test is easy to apply in practice since it is easily computed and has a limiting chi-squared distribution under multivariate normality. A self-contained formal argument is provided that it has the limiting chi-squared distribution. A simulation study is provided to study the accuracy, in finite samples, of the limiting distribution. Finally, a simulation study in a nonnormal distribution is conducted in order to compare the power of our test with those of other popular normality tests.

• Journal of applied mathematics & informatics
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• v.28 no.5_6
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• pp.1227-1237
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• 2010

In this paper, a Klein-Gordon equation is solved by using the homotopy analysis method (HAM), homotopy perturbation method (HPM) and modified homotopy perturbation method (MHPM). The approximation solution of this equation is calculated in the form of series which its components are computed easily. The uniqueness of the solution and the convergence of the proposed methods are proved. The accuracy of these methods are compared by solving an example.