• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.3
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• pp.419-425
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• 1988

It would be very useful if the dynamic response of a vehicle over rough ground could be predicted at the early design stage. This became more promising with the recent progress in computer hardware and software technologies. In this study, a model of a passenger car has been developed for the analysis of its dynamic response. This model can be easily used for the other passenger cars with little modification. This passenger car was modeled to be composed of lumped masses, rigid bodies, and the suspension systems with nonlinear properties. Even though a commercial dynamic simulation program, ADAMS, was used in this study, the developed model is valid for any other simulation program. Finally, the validity of the developed model and the analysis result was verified by an experiment.

• The Journal of the Acoustical Society of Korea
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• v.20 no.2
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• pp.77-85
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• 2001

This paper proposes a method of time-scale modification of polyphonic audio signals based on a sinusoidal model. The signals are modeled with sinusoidal component and noise component. A multiresolution filter bank is designed which splits the input signal into six octave-spaced subbands without aliasing and sinusoidal modeling is applied to each subband signal. To alleviate smearing of transients in time-scale modification a dynamic segmentation method is applied to subbands which determines the analysis-synthesis frame size adaptively to fit time-frequency characteristics of the subband signal. For extracting sinusoidal components and calculating their parameters matching pursuit algorithm is applied to each analysis frame of subband signal. In accordance with spectrum analysis a psychoacoustic model implementing the effect of frequency masking is incorporated with matching pursuit to provide a resonable stop condition of iteration and reduce the number of sinusoids. The noise component obtained by subtracting the synthesized signal with sinusoidal components from the original signal is modeled by line-segment model of short time spectrum envelope. For various polyphonic audio signals the result of simulation shows suggested sinusoidal modeling can synthesize original signal without loss of perceptual quality and do more robust and high quality time-scale modification for large scale factor because of representing transients without any perceptual loss.

• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.6 s.40
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• pp.13-22
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• 2004

Ductiluty factor has played an important role in seismic design as it is key component of response modification factor(R). In this stuty, ductility factors() are calculated by multiplying ductility factor for SDOF systems() and MDOF modification factors(). Ductility factors() for SDOF systems are computed from nonlinear dynamic analysis undergoing different level of displacement ductiluty demands and period when subjected to a large number of recorded earthquake ground motions. The MDOF modification factors() are proposed to account for the MDOF systems, based on previous studies. A total of 108 prototype steel frames are designed to investigate the ductility factors considering the number of stories(4, 8 and 16-stories), framing system(Perimeter Frames, PF and Distributed Frames, DF), failure mechanism(Strong-Column Weak-Beam, SCWB and Weak-Column Strong-Beam, WCSB), soil profiles(SA, SC and SE in UBC 1997) and seismic zone factors(Z=0.075, 0.2 and 0.4 in UBC 1997). It is shown that the number of stories, failure mechanisms (SCWB, WCSB), and soil profiles have great influence on the ductility factors, however, the structural system(Perimeter frames, Distributed frames), and seismic zones have no influence on the ductility factors.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.2023-2028
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• 2004

This paper reveals the utilization of the multi-gent system that based on the Blackboard system basis as the controller of Soccer Robot. This system is a portion of developing the Soccer Robot team for Robocup 2004 Competition. In this development, the intelligent control system was initiated by the combination of parallel and distributed blackboard structures with the principle design that generated from human body structures, which consists of the combination of two main systems, the organs system and the brain system. The system is designed using the control system theory based on Blackboard basis. Modification of the initial structures to corroborate the Soccer Robot and the structure's constituents are clarified accordingly. To demonstrate the idea, ITE-old team is given as a case study.

• The KSFM Journal of Fluid Machinery
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• v.8 no.1 s.28
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• pp.16-22
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• 2005

This paper presents the method of ROL(Rate Of Loading) improvement for the Motor Operated Gate Valve operated in high differential pressure condition. ROL is one of the most important evaluation parameters for the valve ability. It is close to correlation in stem factor (SF) and appears different value by the differential pressure of fluid. ROL and SF are analyzed by the static test and dynamic test. The obtained result show that the modification of stem factor is very important factor for the ROL improvement. In order to obtain the same value of SF between static and dynamic test, stem and stem nut should be combined appropriately by the repetition test.

• Journal of KSNVE
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• v.8 no.4
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• pp.670-682
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• 1998

Ball type automatic balancer is used to reduce the vibration caused by unbalance of rotor. In this study, A analytic modeling of a front loaded washing machine with ball type automatic balancer has been suggested theoretically and ADAMS has been used to analyze the dynamic characteristics of automatic balancer. It is found from simulation and experimental results that the automatic balancer suppress the steady state vibration of washing machine effectively. The test results match with the simulation results of ADAMS, thereby the dynamic model of ADAMS can be used as virtual prototype to predict the vibration characteristics which could be changed by the modification of design variableand can reduce the design cycle sharphy. To maximize the balancing effect of automatic balancer, the friction between balls and race and the deviation between geometric center and rotation center of drum need to be minimized and the optimum design for the stiffness of flange shaft and the angular acceleration of drum should be achieved.

• 유체기계공업학회:학술대회논문집
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• 2003.12a
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• pp.562-567
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• 2003

This paper presents the method of Rate of Loading(ROL) improvement for the Motor Operated Gate Valve operating in high differential pressure condition. The character of ROL and Stem Factor is analyzed. Static test and dynamic test were performed and acquired the diagnosis signal for the valve closing stroke. The result of this study is the modification of stem factor is very important factor for the ROL improvement. In order to obtain the same value of dynamic test thread friction coefficient stem and stem nut should be combined appropriately.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.10a
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• pp.119-131
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• 1997

Ball type automatic balancer is used to reduce the vibration caused by unbalance of rotor. In this study, A analytic modeling of a front loaded washing machine with ball type automatic balancer has been suggested theoretically and ADAMS has been used to analyze the dynamic characteristics of automatic balancer. It is found from simulation and experimental results that the automatic balancer suppress the steady state vibration of the washing machine effectively. The test results match well with the simulation results of ADAMS, thereby the dynamic model of ADAMS can be used as virtual prototype to predict the vibration characteristics which could be changed by the modification of design variable and can reduce the design cycle sharply. To maximize the balancing effect of automatic balancer, the friction between balls and race and the deviation between geometric center and rotation center of drum need to be minimized and the optimum design for the stiffness of flange shaft and the angular acceleration of drum should be achieved.

• Journal of the Korean Society of Industry Convergence
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• v.4 no.2
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• pp.167-175
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• 2001

In this study, a general perturbation method is presented to reanalysis dynamic response of base-isolated systems. The perturbation is expanded to general order and which provide the formulation of perturbed solutions. in which eigensolutions of non-modified system are treated as unperturbed solutions. The accuracy of present method is tested using a 2-DOF system with isolator, where the stiffness and damping coefficients of isolator are changed, respectively, The reanalyzed eigensolutions and response using perturbed solutions are successfully approached to exact ones after just first perturbation. Supposing the practical criterion as ${\pm}5%$ error, the modification range of -50%~30% from original system can be allowed for the first order perturbation. Using higher order solutions, the applicable range will be wide.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.6A
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• pp.607-616
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• 2009

In this paper, a method is proposed to accurately and efficiently estimate the equivalent added mass of hydro-dynamic pressure on dam floodgates subjected to earthquake loading. The present method is based on a relatively-simple procedure using on-site vibration measurement and finite element frequency analysis, which is sufficiently practical to be used in the earthquake resistance performance evaluation of dam floodgates.