• KSCE Journal of Civil and Environmental Engineering Research
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• v.9 no.4
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• pp.51-61
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• 1989

The classical spectral analysis of random vibration is not applicable to the random vibration of nonlinear structures or the dynamic response of active mechanical systems whose governing equations contain random parametric and inhomogeneous excitations. If the random load is simulated, dynamic responses can be obtained with the application of numerical integration schemes to the governing equations of above problems. Thus, in this paper, efficient and practical methods of simulating nonstationary random seismic ground accelerations are presented by using the fast Fourier transform technique. Typical applications of the simulated ground accelerations are the simulations of the dynamic response of rotor-bearing systems under earthquake excitations. The study of accuracy is presented to determine the applicability and practicality of methods of simulation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.11 no.3
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• pp.211-216
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• 1986

This paper presents theoretical analysis and experimental results on an improved interference rejection circuit in the presence of continuous wave interference at center frequency, particularly in a wide-band communication systems. This circuit is based upon a phase locked loop for estimating the CW interference phase and the MSE technique to minimize the estimation error. Therefore, the introduced rejection circuit that minimized the estimated phase error outperforms the rejection circuit with phase estimation only. As a result of experiment, we confirm that this proposed rejection circuit gives a high degree of interference rejection performances when the input J/S is large.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.6
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• pp.2804-2811
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• 2012

In this study, It is developed a retrofitting procedure of RC column with rectangular section to archive the target displacement at failure. Nonlinear behavior of the column is considered as the equivalent linear system. First, target displacement is determined, and then elastic displacement spectrum is constructed to estimate the equivalent natural vibration period of the SDOF system. After natural vibration period is determined, required strength is calculated using secant stiffness based on the mass of system. In accordance with, obtained force-displacement relationship through non-linear fiber based section analysis, retrofit design was carried out to meet required strength. As a result, retrofitted RC column can confirm that the improved seismic performance. It is observed that the proposed design procedure can be applicable to seismic retrofitting design of columns.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2002.10a
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• pp.161-166
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• 2002

As offshore oil fields move towards the deep ocean, the oil production systems such as FPSO are being built these days. Generally, the FPSO is moored by turret mooring lines to keep the position of FPSO. Thus nonlinear motion analysis of moored FPSO must be carried out in the initial design stage because sea environments affect motion of it. In this paper the mathematical model is based on the slow motion maneuvering equations in the horizontal plane considering wave, current and wind forces. The direct integration method is employed to estimate wave loads. The current forces are calculated by using mathematical model of MMG. The turret mooring forces are quasi-statically evaluated by using the catenary equation. The coefficients of a model for wind forces are calculated from Isherwood's experimental data and the variation of wind speed is estimated by wind spectrum according to the guidelines of API-RP2A. The nonlinear motions of FPSO are simulated under external forces due to wave, current, wind including mooring forces in time domain.

• Journal of Radiation Protection and Research
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• v.11 no.1
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• pp.57-64
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• 1986

This paper described an improved technical method required for proper evaluation of personnel exposures by means of the photographic dosimeter developed by KAERI in lower gamma or X-ray energy regions, with which response of the dosimeter varies significantly. With calibration of the dosimeter in the energy range from 30 to 300 keV, the beam spectrum was carefully selected and specified it adequately. The absorber combinations and absorber thickness used to obtain the specified X-ray spectra from a constant potential X-ray machine were determined theoretically and also experimentally. A correlation between the density and exposure for the four separate energies, such as $49\;keV_{eff},\;154\;keV_{eff}\;250\;keV_{eff}\;and\;662\;keV$, is experimentally determined. As a result, it can be directly evaluated the exposure from the measured response of dosimeter.

• The Journal of the Convergence on Culture Technology
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• v.8 no.1
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• pp.175-190
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• 2022

Abusive supervision occurs in a social context in which third-party observers react and interact with the abused victims and supervisors. Despite the importance of third-party observers' behavior in abusive supervision, research on abusive supervision has mainly focused on the dyadic relationship between direct victims and supervisors. Although in recent years research on third parties' reactions to peer abusive supervision has attracted growing attention, there are still insufficient studies examining the topic especially within domestic research in Korea. As such, this study comprehensively reviews empirical studies on third parties' reactions to peer abusive supervision and aims to broaden the scope of research in the field. Firstly, the results of previous studies show that the effects of observed peer abusive supervision are mediated by cognitive and affective processes. Secondly, previous studies are found to investigate the boundary conditions where the effects of observed peer abusive supervision can be amplified or mitigated with regard to various outcomes. Overall, compared to research on direct victims, research on third-party observers of abusive supervision is found to capture a wider spectrum of responses. In order to explain the mechanisms of this phenomena, this study thoroughly examines theoretical assumptions presented in previous studies and categorizes them into five theory types. Finally, this study identifies a couple of central methodological issues, including common method bias and inadequate model specification in the literature and suggests future research directions.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.3
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• pp.157-165
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• 2006

The change of external/internal factors of the cell rquires specific biological functions to maintain life. Such functions encourage particular genes to jnteract/regulate each other in multiple ways. Accordingly, we applied a linear decomposition model IFSA, which derives hidden variables, called the 'expression mode' that corresponds to the functions. To interpret gene interaction/regulation, we used a cross-correlation method given an expression mode. Linear decomposition models such as principal component analysis (PCA) and independent component analysis (ICA) were shown to be useful in analyzing high dimensional DNA microarray data, compared to clustering methods. These methods assume that gene expression is controlled by a linear combination of uncorrelated/indepdendent latent variables. However these methods have some difficulty in grouping similar patterns which are slightly time-delayed or asymmetric since only exactly matched Patterns are considered. In order to overcome this, we employ the (IFSA) method of [1] to locate phase- and shut-invariant features. Membership scoring functions play an important role to classify genes since linear decomposition models basically aim at data reduction not but at grouping data. We address a new function essential to the IFSA method. In this paper we stress that IFSA is useful in grouping functionally-related genes in the presence of time-shift and expression phase variance. Ultimately, we propose a new approach to investigate the multiple interaction information of genes.