• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.1054-1057
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• 2003

A Real Time Mode Selecting Stochastic Controller (RTMSSC) is developed as a new control strategy for a vibrating system under irregular disturbance. Displacement information and frequency characteristics obtained from me::id analysis of the system are used to design a Mode Selecting Controller. This Paper explains design technique of RTNSSC by applying it to the suppression of a flexible beam experiencing random vibration. The RTMSSC is designed by stochastic control from the modal information. The frequency information of the flexible system is utilized from the Mode Selecting Unit (MSU) based on a Fast-Fourier Transformation algorithm. The performance of the proposed technique, RTMSSC, is compared with that of Real Time Stochastic Controller developed recently, which show quite promising results.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.689-694
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• 2003

An iterative modal analysis approach is developed to determine the effect of transverse open cracks on the dynamic behavior of simply supported pipe conveying fluid subject to the moving mass. The equation of motion is derived by using Lagrange's equation. The influences of the velocity of moving mass and the velocity of fluid flow and a crack have been studied on the dynamic behavior of a simply supported pipe system by numerical method. The presence of crack results in higher deflections of pipe. The crack section is represented by a local flexibility matrix connecting two undamaged beam segments i.e. the crack is modelled as a rotational spring. Totally, as the velocity of fluid flow and the crack severity are increased, the mid-span deflection of simply supported pipe conveying fluid is increased. The time which produce the maximum dynamic deflection of the simply supported pipe is delayed according to the increment of the crack severity.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.269-274
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• 2003

Vibration table is required to obtain high packing density in expendable pattern casting process. Packing density, which is an important manufacture factor, depends on the vibration pattern induced by vibration table. Modal test is utilized to identify the dynamic characteristics of vibration table. And finite element method is used to modify flask by fixing the stiffener. The positions of stiffener to modify are found and the natural frequency could be easily shifted to the objective value by using sensitivity analysis.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.120-124
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• 2003

NVH issue at idle condition is one of the major concerns of Passenger and Commercial Vehicle including Sports Utility Vehicle Especially steering wheel vibration at idle condition is a very complex problem and affected by firing frequency of the engine, stiffness of a steering wheel system and the body to which the steering wheel system is attached. To avoid vibration mode coupling between each system of a vehicle, experimental and analytical method has been used at the pre-prototype stage. The resonance frequency of the body and the frame has been decoupled by CAE and the resonance frequency of steering wheel system has been set in between the 1st bending frequency of body and frame. These Results has been used as design guidelines tot the prototype drawing stage. The experimental verification of tile modified pre-prototype vehicle shows good results of the vibration mode decouple. Modal test of prototype vehicle also confirms the vibration mode decouple between each system.

• International Journal of Contents
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• v.4 no.4
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• pp.24-29
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• 2008

In 1920s, Soviet silent films enjoyed unprecedentedly great prosperity throughout world film history. Particularly, Dziga Vertov could develop 'montage' in collaboration with Sergei Eisenstein and thereby could work as the engines behind development and leap of Soviet films toward 'new concepts' of 'new films' worldwide. However, Vertov's original reputations - the best film theorist and avant-gardist as well as great cineaste in his contemporary age - have been misunderstood or underestimated, so that he has been still misestimated or distorted as radical formalist and documentary propagandist. In regard to these points, this study aims to take Gilles Deleuze's modal esthetic approaches to further considering and historically re-highlighting D. Vertov's film theories that are based on the principle of 'film-reality' and the concept of 'Life As It Is' according to 'kino-eye' method and 'interval' theory as a part of futurism and constructivism breaking down any attribute of traditional narrative films.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.342-347
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• 2004

The dynamic responses of a PSC bridge for automated guide-way transit system are investigated by analytical approach of bridge-vehicle interaction. In this study, the dynamic responses, concerned with a spall on the surface of bridge are emphasized. A simply supported pre-stressed concrete bridge is adopted as a numerical example. Dynamics of three-dimensional dynamic interaction system between bridges and vehicles is considered in this study. The FE method and modal analysis is used for modeling a bridge for dynamic response analysis. An AGT vehicle is idealized as a model with 11DOFs including lateral motion. It was found that the dynamic responses of bridge can be affected by a spall of surface. Especially, the vibrations are increased much more when a spall is exist.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.4
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• pp.227-227
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• 2004

In stressed power system due to the presence of increased nonlinearity and the existence of nonlinear modal interactions. there exist some limitations to the use of conventional linear system theory to identify the optimum sites for a controller. This paper suggests an approach based on the method of normal forms to identify the optimum sites for controllers with incorporating the nonlinear interaction . In this paper, nonlinear participation factors and coupling factors are proposed as measures of the nonlinear interactions, and identification procedure of optimum sites for a controller is also proposed. The proposed procedure is applied to the 10-generator New England System and the KEPCO System in the year of 2010, and the results illustrate its capabilities.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.170-172
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• 1999

This paper deals with modal analysis and displacement of stator in SRM due to electromagnetic forces according to the rotor position. The analysis is performed by using 3 dimensional Finite Element Method(FEM). And, the prediction of resonance speed is achieved from the comparison with current harmonic according to duty ratio of voltage source and the natural frequencies.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.10a
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• pp.257-264
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• 2000

Nonlinear dynamic time history analysis of a structure with energy dissipation devices is complicated and time consuming. In this regard the nonlinear static analysis is a practical alternative for evaluating the earthquake resisting capacity of a structure. In this study the nonlinear static response of a structure was obtained first, and the equivalent viscous modal damping ratio required to satisfy the performance objective was computed in the capacity spectrum format. Then proper amount of viscous dampers were installed to provide the required damping. Parametric study has been performed for the period of the structure, yield strength, and the stiffness after the first yield. According to the earthquake time history analysis results, the maximum displacement of the model structure with viscous dampers designed in accordance with the proposed method corresponds well with the target displacements that was used in the beginning of the design process.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1998.10a
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• pp.20-27
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• 1998

In the current seismic design codes design earthquake is usually defined as the earthquake with the 90 percent probability of not being exceeded in the life time of a structure which is assumed as 50 years equivalent to the earthquake with 475 year recurrence period. However the life time of tall building structures may be much longer than 50 yers. The current seismic design code requires the modal analysis or dynamic time history analysis for the buildings with the height exceeding a certain height limit. The objective of this study is to collect the earthquake ground motion(EQGM) which can be used for dynamic time history analysis for tall buildings. For this purpose linear elastic design response spectrum (LEDRS) in the code is scaled to account for the recurrence period of the design earthquake. The earthquake ground motions which has been recorded are calibrated to fit the scaled LEDRS. The set of calibrated EQGM can be treated as design EQGM for the design of tall building with longer lifetime than ordinary building.