• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.836-839
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• 2005

The in-plane vibration response of a clamped circular plate should be predicted in many applications. Up to now, papers on the in-plane vibration of rectangular plate are published. However, analytical derivation on the in-plane vibration of the clamped circular plate is not carried out. Therefore, the in-plane vibration of the clamped circular plate is the concern of this paper. In order to derive the equations of motion for the clamped circular plate in the cylindrical coordinate, the kinetic energy and potential energy for the in-plane behavior are obtained by us ing the stress-strain-displacement expressions. Application of Hamilton's principle leads to two sets of differential equations. These displacement equations were highly coupled. It is possible to obtain a simpler set of equations by introducing Helmholtz decomposition. Substituting them into the coupled differential equations, we obtain the uncoupled equations of motion. In order to solve them, we assume that the solutions are harmonic. Then, they lead to the wave equations. Using the separation of variable, we obtain the general solutions for the equations. Based on the solutions, the displacements for r and $\theta$ direction are assumed. Finally we obtain the frequency equation for the clamped circular plate by the application of boundary conditions. The derived equation is compared with the finite element analysis for validation by using the some numerical examples.

• The Journal of the Acoustical Society of Korea
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• v.10 no.3
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• pp.13-18
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• 1991

In this study, the analysis technique of fracture stress using the reflection coefficient of SAW reflected from a brittle solid with surface crack has been studied. Fracture stress of brittle solid with surface crack has been obtained by the function of the critical stress intensity factor and the maximum normalized stress intensity factor of the crack in the body. And the maximum normalized stress intensity factor of a surface crack can be inferred from a measurement of reflection coefficient of SAW. In experiment, the surface cracks ranging from 0.5mm to 0.9mm in crack depth has been made at the center of each Pyrex disc, and the SAW wedge transducer has been set up for the pitch-catch mode. It has been compared the theoretical values of the fracture stress calculated from the reflection coefficient of SAW with the values of the fracture stress measured from UTM.

• Knowledge Management Research
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• v.10 no.3
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• pp.81-98
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• 2009

The purpose of this study is to investigate the effect of Hallyu(Korean Wave) and marketing mix elements on brand equity based on the Korean cosmetic brand in China Market. It will provide the constructive suggestions to build Korea brand equity in overseas market through empirical research. At the beginning of this study, in order to analyze the effect of Hallyu and marketing mix elements on brand equity, we studied literature reviews on relationships between brand equity and marketing mix elements, culture, Hallyu and its influences on marketing. And then, we set up the research model, hypotheses and variables. The chosen variables to investigate are price premium, price deals, store image, distribution intensity, advertising, Hallyu, perceived quality, brand loyalty, brand awareness/associations, and brand equity. The results of the study reveal that Hallyu and advertising had a positive influence on perceived quality, brand loyalty and brand awareness/associations, but the other marketing elements had partial influence. All of perceived quality, brand loyalty and brand awareness/associations showed positive effects on brand equity. Additionally, theoretical and managerial implications of brand equity and Hallyu based on the results of this study are discussed. And limitations and future research issues are also presented.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.10
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• pp.960-964
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• 2005

In this paper, we dealt with a partial discharge(PD) measurement method that has been accepted as an effective and non-destructive technique to estimate insulation performance of low-voltage electric and electronic devices. The PD measurement system Is composed of a coupling network, a low noise amplifier, and associated electronics. h shielded box Is adopted to make a better measurement environment against around noise. A low cut-off frequency of the coupling network estimated by a sinusoidal wave input was 125 kHz (-3 dB). Calibration tests on laboratory set-up have shown that the PD measurement system has a stable sensitivity of 10 mV/pC. In an application test oil a low-voltage three phase Induction motor (5 HP), we could detect 0.53 pC level of partial discharge at the applied voltage of AC 650 $V_{peak}$.

• Journal of the Earthquake Engineering Society of Korea
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• v.19 no.3
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• pp.103-108
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• 2015

This work introduces a modal testing and analysis results of the mock-up for a layered stone pagoda. The pagoda has been horizontally excited by an impact hammer. As to the measured acceleration time responses, the first five lower mode shapes and natural frequency are extracted by the TDD technique. It is observed that the time delay of a shear wave occurs through friction surfaces. Such phenomena cannot be described by using the traditional analytical models such as a continuum cantilever beam model or a discrete shear building model. However, the time delay typically affects only the phases of the pagoda system. The frequencies of the pagoda system are not affected by such time delay. It is found in the first time that the layered stone pagoda system has a set of closely placed modes in near of natural frequency. It is believed that such modes are due to the friction characteristics in friction surfaces. Based on the stick-slip friction model, it seems that the one of the closely placed mode can be a self-excited one.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.10
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• pp.1445-1450
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• 2001

Stall inception in a high-speed centrifugal compressor has been examined. The main objective was to find stall precursor and to develop a reliable stall warning method. For stall warning, a method which uses the spectrum at impeller frequency is suggested. The use of the spectrum at impeller frequency as a stall warning method showed a warning time of about two hundreds impeller revolutions. This method uses only one sensor that it has made the stall warning method more useful. And the well-known traveling wave energy method proved to be a good method for stall warning also in a high-speed centrifugal compressor. The warning time was about one hundred impeller revolutions at lower speeds, and about one thousand impeller revolutions at higher speeds. The stall warning methods used here were found to be robust and reliable. Therefore, it seems to be promising to set up a reliable stall avoidance control based on this analysis.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.9
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• pp.777-784
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• 2007

With the development of micro electronic circuits and optical equipment, the demand for developing smart munitions with the ability to autonomously search for and attack targets has increased. Since the electronic components within smart munitions are affected by high temperatures, pressure, and impulsive forces upon the combustion of gunpowder, stability and reliability need to be secured for them. Securing those stability and reliability requires soft recovery system which can decelerate smart munitions. A theoretical analysis of flow is performed for the secure recovery of bullets on the basis of Euler equation for compressible fluids. The inner pressure on a pressure tube, the speeds of bullets, and the deceleration of munitions are calculated theoretically. Theoretical results are compared with the data from the experiment with soft recovery system set up at the laboratory.

• The Journal of Korean Medicine
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• v.18 no.1
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• pp.143-156
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• 1997

This report was conducted to quantify the pulse/respiration ratio and set up the normal range of wan-maeck(緩脈). In order to objectify the pulse diagnosis and use as basic clinical index of Cold-Hot diagnosis, we developed the hardware and software for detection and interpretation of pulse/respiration ratio, pulse/expiration ratio, pulse/respiration ratio, inspiration time, expiration time, respiration frequency, respiration time, duration of one pulse and pulse and pulse rate per minute, The results were as follows; pulse/respiration ratio is $4.30{\pm}1.03$ times, pulse/respiration ratio is $1.60{\pm}0.32$ times, pulse/respiration ratio is $2.37{\pm}0.75$ times, inspiration time is $1.35{\pm}0.20$ sec, expiration time is $1.89{\pm}0.39$ sec, respiration frequency is $17.16{\pm}3.49$ times/min, total respiration time is $3.63{\pm}0.71$ sec, duration of a pulse is $0.86{\pm}0.15$ sec, pulse rate is $71.51{\pm}12.30$ times/min.

• Transactions of The Korea Fluid Power Systems Society
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• v.2 no.2
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• pp.8-13
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• 2005

This paper investigates a fast, accurate and inexpensive hydraulic motor speed control system using high speed on-off solenoid valves. In order to retain the advantages of the two position valve and obtain better performance, the valves are operated by pulse width modulation(PWM) control. PWM signal is generated from a LabWIEW program in microcomputer in order to set up various duty ratio and frequency of carrier wave in PWM signal with varying system parameters. As the results of experiments, the speed control of a hydraulic motor was successfully implemented using on-off solenoid valves. In order to attenuate the pressure ripple and speed variation due to discontinuously controlled flow through the on-off valves, a resonator hose fabricated for automobile power steering system was connected between the valve and a hydraulic motor. From experimental results obtained in the hydraulic motor system with a resonator hose, it was ascertained that the resonator hose showed excellent performances in reducing pressure ripple and motor speed variation.

• Journal of Arbitration Studies
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• v.23 no.1
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• pp.85-105
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• 2013

The entertainment industry has developed along with current Korean wave fever, and so entertainment-related disputes are increasing rapidly. Litigation is a poor fit for entertainment disputes because of characteristics such as temporal sensitivity. Thus, in the US, the entertainment industry resolves these disputes through ADR mechanisms like arbitration, but cases of settling such disputes through arbitrations are very rare in Korea. This study examined the characteristics and types of entertainment disputes and considered the compatibility of arbitration as a method for settling disputes, and then suggested tasks for revitalizing arbitration systems as entertainment dispute resolution procedures. Arbitrations have many merits, such as the rapid pace of procedures, confidentiality, satisfying the long-term desires of business relationships, the low cost of settling disputes, judgments rendered by experts, etc.; thus, it is a very suitable mechanism to settle entertainment-related disputes. The study proposes necessary steps for revitalizing arbitration systems for entertainment disputes. First, awareness of entertainment industry workers about the arbitration system should be raised. Second, special educational programs for members the of Korean Commercial Arbitration Board related to entertainment should be set up and operated together with encouraging positive attitudes toward actions like establishing a dedicated arbitration unit on entertainment disputes. Third, neutral, professional arbitrators should be secured and aggressive disclosures made. Fourth, a professional ADR organization such as an "Entertainment Arbitration Committee" should be established.