• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.17 no.1
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• pp.29-45
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• 2013

Central schemes offer a simple and versatile approach for computing approximate solutions of nonlinear systems of hyperbolic conservation laws. However, there are large numerical dissipation in case of contact discontinuity. We study semi-discrete central upwind scheme by changing flux functions to reduce the numerical dissipation and we perform numerical computations for various problems in case of contact discontinuity.

• Journal of the Korean Data and Information Science Society
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• v.18 no.3
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• pp.669-678
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• 2007

An algorithm to detect the number of discontinuity points of the variance function in regression model is proposed. The proposed algorithm is based on the left and right one-sided kernel estimators of the second moment function and test statistics of the existence of a discontinuity point coming from the asymptotic distribution of the estimated jump size. The finite sample performance is illustrated by simulated example.

• Journal of the Korean Data and Information Science Society
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• v.21 no.1
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• pp.51-59
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• 2010

In the case that the regression function has a discontinuity point in generalized linear model, Huh (2009) estimated the location and jump size using the log-likelihood weighted the one-sided kernel function. In this paper, we consider estimation of the unknown number of the discontinuity points in the regression function. The proposed algorithm is based on testing of the existence of a discontinuity point coming from the asymptotic distribution of the estimated jump size described in Huh (2009). The finite sample performance is illustrated by simulated example.

• Journal of the Korean Data and Information Science Society
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• v.14 no.4
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• pp.929-937
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• 2003

Kernel type estimations of discontinuity point at an unknown location in regression function or its derivatives have been developed. It is known that the discontinuity point estimator based on $Gasser-M\ddot{u}ller$ regression estimator with a one-sided kernel function which has a zero value at the point 0 makes a poor asymptotic behavior. Further, the asymptotic variance of $Gasser-M\ddot{u}ller$ regression estimator in the random design case is 1.5 times larger that the one in the corresponding fixed design case, while those two are identical for the local polynomial regression estimator. Although $Gasser-M\ddot{u}ller$ regression estimator with a one-sided kernel function which has a non-zero value at the point 0 for the modification is used, computer simulation show that this phenomenon is also appeared in the discontinuity point estimation.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.9 s.186
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• pp.111-118
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• 2006

A hybrid focus method with multiple laser slits is newly proposed for the measurement of surface morphology with depth discontinuity, and it is based on the integration of DFB and DFF. Rough depth information is estimated through calibration tables which are constructed by DFD with multiple laser slits, and then DFF is applied to only each specific depth range using the rough depth information resulting from DFD. The proposed hybrid method gives more accurate results than DFD and DFF, and faster measurement than DFF in the vicinity of depth discontinuity Its performance is verified through experiments of calibration blocks with sharp depth discontinuity.

• Journal of the Korean Data and Information Science Society
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• v.23 no.1
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• pp.79-87
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• 2012

In the case that the probability density function has a discontinuity point, Huh (2002) estimated the location and jump size of the discontinuity point based on the difference between the right and left kernel density estimators using the one-sided kernel function. In this paper, we consider the cross-validation, made by the right and left maximum likelihood cross-validations, for the bandwidth selection in order to estimate the location and jump size of the discontinuity point. This method is motivated by the one-sided cross-validation of Hart and Yi (1998). The finite sample performance is illustrated by simulated example.

• Journal of the Korean Data and Information Science Society
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• v.16 no.3
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• pp.591-601
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• 2005

In this paper we consider detection of a discontinuity point in the variance function. When the mean function is discontinuous at a point, the variance function is usually discontinuous at the point. In this case, we had better estimate the location of the discontinuity point with the mean function rather than the variance function. On the other hand, the variance function only has a discontinuity point. The target function in order to estimate the location can be used the second moment function since the variance function and the second moment function have the same location and jump size of the discontinuity point. We propose a nonparametric detection method of the discontinuity point with the second moment function. We give the asymptotic results of these estimators. Computer simulation demonstrates the improved performance of the method over the existing ones.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.9
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• pp.109-117
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• 1997

A new relaxation algorithm based on distribution of matched errors and possibility is proposed to solve efficiently correspondence problem. This algorithm can be applied to various method, such as BMA, feature-, and region-based matching methods, by modifying its smoothness function. It consists of two stages which are transformation and iteration process. In transformation stage, the errors obtained by any matching algorithm are transformed to possibility values according to these statistical distribution. Each grade of possility is updated by some constraints which are defined as smoothness, uniqueness, and discontinuity factor in iteration stage. The discontinuity factor is used to reserve discontinuity of disparity. In conventional methods, it is difficult to find proper weights and stop condition, because only two factors, smoothness and uniqueness, have been used. However, in the proposed mthod, the more smoothing is not ocurred because of discontinuity factor. And it is efective to the various image, even if the image has a severe noise and repeating patterns. In addition, it is shown that the convergence rate and the quality of output are improved.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.12
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• pp.146-151
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• 2008

The equivalent circuits of Open End and Step discontinuity effects for Suspended Strip line are obtained. The circuit parameters for each discontinuity effect are represented by equations after optimization based on EM analysis results, and the coefficients of the equations are obtained by curve fitting for all impedance cases.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.477-478
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• 2007

The SCN-TLM method presented in this paper is another independent approaches for obtaining frequency domain results for microstrip line. The structure analysed with this TLM algorithm is step discontinuity microstrip line and the symmetrical condensed node is used. After numerical analysis, the frequency dependent scattering parameters of a step discontinuity microstrip line have been calculated by Fourier transform of the time domain data. From the time domain TLM numerical results, this numerical analysis is shown to be an efficient method for modelling complicated structure as step discontinuity microstrip line.