• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.2
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• pp.268-275
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• 2008

In this paper, we introduce a new method for detecting and estimating faults on a power line using the time-frequency domain reflectometry system. The system rests upon time-frequency signal analysis and uses a chirp signal which is multiplied by Gaussian envelope. The chirp signal is used as a reference signal, and we can get the reflected signal from a fault on a wire. To detect and estimate faults, we analyze the reflected signal by Wigner time-frequency distribution function and normalized time-frequency cross correlation function. In this paper we design an optimal reference signal for power line and implement a system for estimating fault distance on a power line with the TFDR implemented by PXI equipments. This approach is verified by some experiments with HIV 2.25mm power lines.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.2
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• pp.231-235
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• 2013

The purpose of this paper is to compare with estimation of equivalent fatigue load in time domain and frequency domain and estimate the fatigue life of structure with multi-axial vibration loading. The fatigue analysis with two methods is implemented with various signals like random, sinusoidal signals. Also an equivalent fatigue life estimated by rainflow cycle counting in time domain is compared with results estimated with probability density function of each signal in frequency domain. In case of frequency domain, equivalent fatigue life can estimate through Dirlik's method with probability density function. And the work proposed in this paper compared the fatigue damage accumulated under uni-axial loading to that induced by multi-axial loading. The comparison is preformed for a simple cantilever beam, which is exposed to vibrations of several directions. For verification of estimation performance of fatigue life, results are compared to those of FEM analysis (ANSYS).

• International Journal of Naval Architecture and Ocean Engineering
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• v.13 no.1
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• pp.50-56
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• 2021

An accurate evaluation of three-dimensional (3D) Time-Domain Green Function (TDGF) in infinite water depth is essential for ship's hydrodynamic analysis. Various numerical algorithms based on the TDGF properties are considered, including the ascending series expansion at small time parameter, the asymptotic expansion at large time parameter and the Taylor series expansion combines with ordinary differential equation for the time domain analysis. An efficient method (referred as "Present Method") for a better accuracy evaluation of TDGF has been proposed. The numerical results generated from precise integration method and analytical solution of Shan et al. (2019) revealed that the "Present method" provides a better solution in the computational domain. The comparison of the heave hydrodynamic coefficients in solving the radiation problem of a hemisphere at zero speed between the "Present method" and the analytical solutions proposed by Hulme (1982) showed that the difference of result is small, less than 3%.

• Journal of Microbiology and Biotechnology
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• v.17 no.8
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• pp.1385-1389
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• 2007

5-Enolpyruvylshikimate-3-phosphate (EPSP) synthase catalyzes the formation of EPSP and inorganic phosphate from shikimate-3-phosphate (S3P) and phosphoenolpyruvate (PEP) in the biosynthesis of aromatic amino acids. To delineate the domain-specific function, we successfully isolated the discontinuous C-terminal domain (residues 1-21, linkers, 240-427) of EPSP synthase (427 residues) by site-directed mutagenesis. The engineered C-terminal domains containing no linker (CTD), or with gly-gly ($CTD^{GG}$) and gly-ser-ser-gly ($CTD^{GSSG}$) linkers were purified and characterized as having distinct native-like secondary and tertiary structures. However, isothermal titration calorimetry (ITC), $^{15}N-HSQC$,\;and\;^{31}P-NMR$ revealed that neither its substrate nor inhibitor binds the isolated domain. The isolated domain maintained structural integrity, but did not function as the half of the full-length protein.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.5
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• pp.375-379
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• 2009

Protein domain is the conserved unit of compact tree-dimensional structure and evolution, which carries specific function. Domains may appear in patterns in proteins, since they have been conserved through the evolution for functional formation of proteins. In this paper, we propose a formulated method for conservation analysis of domain combination based on association rule. Proposed method measures mutual dependency of domains in a combination, as well as co-occurrence frequency of them, which is conventionally used. Based on the method, we extracted conserve domain combinations in S.cerevisiae proteins and analyzed their functions based on Gene Ontology. From the results, we drew conclusions that domains in S.cerevisiae proteins form patterns whose members are highly affiliated to one another, and that extracted patterns tend to be associated with molecular function. Moreover, the results testified to proposed method superior to conventional ones for identifying domain combinations conserved for functional cooperation.

• Korean Journal of Remote Sensing
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• v.10 no.2
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• pp.1-15
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• 1994

Since Seasat SAR mission in 1978, SAR has become one of the most important surface imaging tools in satellite remote sensing SAR achieves high resolution by signal processing synthesizing a larger aperture. Therefore, SAR signal processing along with antenna technology has been centered upon SAR technologies. Thus interpreters of SAR imagery as well as those who involved in signal processing require the knowledge of the principal SAR processing algorithm. Although the conventional range-Doppler approach has been widely adopted by many SAR processors, azimuth compression including the range migration has been problematic. The recent development of the wavenumber domain approace is able to provide high precision SAR focusing algorithm. Compared with the wavenumber domain algorithm derived by applying Born (first) approximation, the transfer function of the conventional range-Doppler algorithm accounts only for the first order approximation of the exact transfer function. The results of a simulation and an actual test using airborne C-band SAR configuration demonstrate the dxcellent performance of the wavenumber domain algorithm.

• Journal of the Chungcheong Mathematical Society
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• v.16 no.1
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• pp.113-121
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• 2003

This paper is concerned with some properties of stable domains and limit functions. Using the relationship between cycles of periodic stable domains and orbits of critical points and using the Sullivan theorem [19], we prove that the value of a constant limit function in some stable domain for a rational function f of degree at least two lies in the closure of the set of critical orbits of f.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.36T no.1
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• pp.32-40
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• 1999

The analysis of logic function is performed by the spectral coefficients which transform the function domain data into the spectral domain data. By using the spectral techniques, analysis of MVL circuits is performaed, and the fault analysis and detecting methods of multiple-valued logic circuits are proposed in this paper.

• Journal of the Korean Mathematical Society
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• v.43 no.1
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• pp.199-213
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• 2006

We compute the holomorphic derivative of the harmonic measure associated to a $C^\infty$bounded domain in the plane and show that the exact Bergman kernel function associated to a $C^\infty$ bounded domain in the plane relates the derivatives of the Ahlfors map and the Szego kernel in an explicit way. We find several formulas for the exact Bergman kernel and the Szego kernel and the harmonic measure. Finally we survey some other properties of the holomorphic derivative of the harmonic measure.

• Journal of the Korean Mathematical Society
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• v.41 no.1
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• pp.175-192
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• 2004

This talk discusses conditions on the numerical range of a holomorphic function defined on a bounded convex domain in a complex Banach space that imply that the function has a unique fixed point. In particular, extensions of the Earle-Hamilton Theorem are given for such domains. The theorems are applied to obtain a quantitative version of the inverse function theorem for holomorphic functions and a distortion form of Cartan's unique-ness theorem.