• Journal of the Korean Statistical Society
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• v.36 no.1
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• pp.93-109
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• 2007

Gamma distributions are some of the most popular models for hydrological processes. In this paper, a very flexible family which contains the gamma distribution as a particular case is introduced. Evidence of flexibility is shown by examining the shape of its pdf and the associated hazard rate function. A comprehensive treatment of the mathematical properties is provided by deriving expressions for the nth moment, moment generating function, characteristic function, Renyi entropy and the asymptotic distribution of the extreme order statistics. Estimation and simulation issues are also considered. Finally, a detailed application to drought data from the State of Nebraska is illustrated.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.5
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• pp.24-32
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• 1998

Spatial green's functions for a horizontal magnetic dipole in a parallel-plate waveguide are expressed in an improved closed-form with two-level approximation of the spectral green's functions. The results evaluated by the present closed-from green's function with two-level approximation are compard with those obtained the previous closed-form green's function with one-level approximation. The present results are observed to be more acurate than the previous results over wide frequency range as well as whole spatial range. The combination of the present closed-form green's functions and the moment mehtod may help in analyzing the problem of EMP coupling through an aperture into a parallel-plat waveguide and the microstrip slot antenna with a reflector.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1506-1507
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• 2007

For GPR applications, accurate analysis of the scatterered field is necessary to identify the unknown target. Dyadic Green's Function of the multilayered medium is developed and applied to analyse of underground conduting object. We used method of moment(MOM) with dyadic Green's function, and Discrete Complex Image Method(DCIM).

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.9
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• pp.1790-1795
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• 2009

For GPR(Ground Penetrating Radar) applications, an accurate analysis of the scattered field is necessary to identify the unknown target. Dyadic Green's function of the multilayered medium is developed and applied to analysis of the underground conducting object. We used method of moment(MOM) with dyadic Green's function, and Discrete Complex Image Method(DCIM). To reduce the computational complexity, fast multipole method is introduced and we showed the accuracy of the method comparing with the conventional method of moment. For investigating the underground conducting target, several numerical experiments were accomplished using this method.

• Journal of the Earthquake Engineering Society of Korea
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• v.24 no.2
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• pp.59-65
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• 2020

The empirical Green's function method is applied to the foreshock and the mainshock of the 2016 Gyeongju earthquake to simulate strong ground motions of the mainshock and scenario earthquake at seismic stations of seven metropolises in South Korea, respectively. To identify the applicability of the method in advance, the mainshock is simulated, assuming the foreshock as the empirical Green's function. As a result of the simulation, the overall shape, the amplitude of PGA, and the duration and response spectra of the simulated seismic waveforms are similar with those of the observed seismic waveforms. Based on this result, a scenario earthquake on the causative fault of Gyeongju earthquake with a moment magnitude 6.5 is simulated, assuming that the mainshock serves as the empirical Green's function. As a result, the amplitude of PGA and the duration of simulated seismic waveforms are significantly increased and extended, and the spectral amplitude of the low frequency band is relatively increased compared with that of the high frequency band. If the empirical Green's function method is applied to several recent well-recorded moderate earthquakes, the simulated seismic waveforms can be used as not only input data for developing ground motion prediction equations, but also input data for creating the design response spectra of major facilities in South Korea.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.10
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• pp.2703-2709
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• 1996

This paper proposes an exact numerical method for analyzing a dipole antenna attached on a dielectric slab. A Green's function for an infinitesimal current filament on a dielectric slab is derived and a field integral equation is formulated using a boundary condition. The moment Method is used to solve the field integral equation to otain current distribution on the antenna. Since an asymptotic function is used to compute the impedance matrix elements, the computataion time is significantly reduced. Using the computed current distributions, the input impedances, the resonance lengths and the resonant resistances of the antennas for various values of the thichnessandthe dielectric constant of the slab are obtained. It was found that the resonant length and the resonant resistance are decrease monotonically as the dielectric constant increases, however, those are changed up-and-down as the substrate thickness increases.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.8
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• pp.375-381
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• 2002

A rigorous analysis of a broad wall slot array is presented. The slot is longitudinal and offset from the center line in the rectangular waveguide. Pertinent integral equations are developed, taking into account finite wall thickness. The mothed of moment with entire basis function is used to solve a pair of coupled-integral equations, derived from the electromagnetic boundary conditions using modified Green's function, to find the tangential electric field on the upper and lower surfaces of the slot. Numerical results for resonant length and scattering parameters of the slots are Presented over a range of offset. Computed results are compared with experimental result.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.1
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• pp.143-149
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• 1993

An approach is presented for efficient numerical integration of the Sormnerfeld type integrals pertinent to the microstrip surface Green's function arising in the problem of an electric current point source on an infinite planar grounded dielectric substrate. This approach, valid for both lossless and lossy dielectric substrates, is based on the deformation of the integration contour via a coordinate transformation and Cauchy's residue theory, and identifies clearly the effects of surface waves. I ts useful application is in a rigorous moment method analysis of micros trip antenna arrays and microstrip guided wave structures. The efficiency and the usefulness of the present approach are emphasized through some numerical calculations of the impedance matrix elements with associated CPU times.

• Journal of the Korean Society of Hazard Mitigation
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• v.1 no.3 s.3
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• pp.123-136
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• 2001

The purpose of application of moment tensor inversion method is to determine source parameters, such as, focal mechanism, seismic moment and source depth. This paper presents results of focal mechanism solutions of 14 recent events with magnitudes ranging from M3.3 to M4.8 by using moment tensor inversion method called TDMT_INV. The strike of faults is in the direction of NE-SW and NW-SE with the movement of strike-slip or strike-slip of minor reverse component. The compressional axis of the stress field is predominantly E-W or ENE-WSW except for some faults, which are distributed at Ryongnam Massif and Wonsan, they have a compressional axis of N-S or NNW-SSE.

• Journal of electromagnetic engineering and science
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• v.7 no.2
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• pp.59-63
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• 2007

This paper suggests a novel method to efficiently calculate the spatial-domain Green's functions of 2D electromagnetic problems Briefly speaking, this method combines spectral and spatial domain calculation schemes and prevents the Green's functions from poor convergence due to the singularities that complicate the process of the Method of Moment(MoM) applications For the validation of this proposed method, fields will be evaluated along the spatial distance including zero distance for 2D free-space and periodic homogeneous geometry The numerical results show the validity of the prosed method and correspondng physics.