• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.8
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• pp.426-432
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• 2004

This paper presents a systematic approach of measurement, modeling and analysis of grounding system impedance in the field of lightning protection system and intelligent power equipments. The measurement and analysis system of ground impedance is based on a computer aided technique. The magnitude and phase of ground impedance were determined by the novel measurement and analysis using the revised fall-of-potential method. The ground impedances of the ground rod of 50 m long are considerably dependent on the frequency. The ground impedance is mainly resistive in the frequency range of 3-20 kHz. At higher frequencies, the reactive components of the ground impedances are no longer negligible and the inductance of the ground rod was found to be the core factor deciding the ground impedance. Although the steady-state ground resistance of the ground rod of 50 m was less than that of the ground rod of 10 m, the ground impedances of the ground rod of 50 m over the frequency range of more than 60 kHz were much greater than those of the ground rod of 10 m. Furthermore, the equivalent circuit model based on the measured data was proposed. and the calculated results were in approximately agreement with the measured data.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.5
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• pp.393-399
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• 2011

An empirical formula proposed by Petersson and Plunt(PP's formula) and finite element analysis for impedance calculation of ship equipment foundations are investigated by comparing the analysis results with those of experimental results. The PP's formula well estimates resonant frequency of the foundations and impedance level except around the resonant region although the impedance level around the resonant frequency is heavily dependent upon the assumed loss factor. The results show that the PP's formula and finite element models can be complementarily used to estimate the impedance characteristics of various types of foundation of ships in design stage.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.783-786
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• 2010

This paper presents a finite element analysis on impedance parameters of anchor plates of structural cables under the change in cable forces. To achieve the objective, four approaches are implemented as follows: Firstly, theoretical background of electro-mechanical impedance is described. Secondly, anchor plates of structural cables are selected to experimentally examine the relationship between impedance parameters and cable force changes. Thirdly, finite element analysis is performed to verify the experimental results. Fourthly, a comparison between the experimental and numerical analysis on impedance parameters of anchor plate of structural cables under cable force changes is carried out.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.3
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• pp.1-5
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• 2011

In order to analyze the impedance properties of high integrated impedance network with multiple terminals, this paper introduces the concept of impedance relation matrix(IRM). The linear relation between the terminal voltages and currents is represented in the form of IRM and this matrix can be utilized to calculate the impedance between any two terminals. Furthermore, IRM representation for 2-port impedance network can be also defined. The whole impedance network is divided into the several 2-port sub-networks and each sub-network is analyzed in a form of the IRM representation. An illustrated example is given to show that the proposed method is simple and effective to analyze the impedance of a sensor array which has a very large number of impedance elements.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.2174_2175
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• 2009

This Paper present about loop impedance characteristic based on korea internal electrical environment. Analysis parameters were touch voltage, electrical shock current and human body resistance. Result, For protect of electrical shock must measuring of loop impedance. And current capacity & loop impedance are must important parameters.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.11a
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• pp.231-234
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• 2007

This paper presents an analysis method of transient ground impedance using the lightning impulse and variable frequency currents. The transient ground impedance strongly depends on the configuration and size of grounding electrodes and the shapes of impulse currents, and the inductance of grounding electrodes has a significant affect on the transient impedance of the grounding system. There are some differences between the effective impulse ground impedance which was introduced some papers and the transient ground impedance. The transient ground impedance measured from the peak value of impulse voltage and the peak value of impulse current is more reliable than the effective impulse ground impedance.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.10
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• pp.1861-1868
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• 2009

A ground electrode subjected to lightning surge current shows the transient impedance behaviors. The ground electrode for protection against lightning should be evaluated in view of the transient grounding impedance and conventional grounding impedance, not ground resistance. The transient impedance characteristics of ground electrodes are influenced by the shape of ground electrode and the soil characteristics, as well as the waveform of lightning surge current. In order to propose a simulation method of analyzing the transient impedance characteristics of the grounding system in practical use, this paper suggests a theoretical analysis method of distributed parameter circuit model to simulate the transient impedance characteristics of counterpoise subjected to lightning surge current. EMTP and Matlab programs were employed to compute the transient grounding impedances of three counterpoises with different lengths. As a consequence, the simulated results using the proposed distributed parameter circuit model are in good agreement with the measured results.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.325-329
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• 2003

In this paper. the stability and performance analysis of wave-based teleoperation system is presented. For stability and performance analysis with respect to the variation of characteristic impedance b, loop gains of communication channel and minimum value of trasmitted impedance from slave side to the master side are considered. The stability of slave side may be enhanced by increasing characteristic impedance b, whereas exssively high value of b may degrade the performance, which imply a tradeoff between stability and performance.

• Transactions on Control, Automation and Systems Engineering
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• v.4 no.1
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• pp.2-8
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• 2002

This paper discusses haptic display for grasping a virtual object by two fingers. Much research has been done on fundamental analysis for stability of haptic display. But it is difficult to apply the results immediately to grasping situations by two fingers, since the studies usually deal with a single device and a single object and the fingertip force in grasping situations has two components, internal and external components. The conventional methods, which specify the coupling impedance at each contact point separately, have no other alternative but to specify the impedance for the sum of the internal and external components. So even if only the impedance for the external force should be changed, the impedance for the internal force is also changed at the same time. In this paper, a new method, in which the coupling impedance is specified separately for the internal and external forces, is proposed and the stability of the proposed method is discussed using passivity analysis for 1 -DOF(Degree-Of-Freedom) system. Finally, some experiments are performed to study the effects of the proposed method.

• Journal of Biosystems Engineering
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• v.33 no.4
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• pp.269-275
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• 2008

This study was conducted to design an impedance sensor that can measure soil water content of soils. Partial least square regression (PLSR) was applied to soil impedance data preprocessed with a smoothing method. An optimal sub-spectrum size and wavelength range were determined by comparing the coefficient of determination ($R^2$) and root mean square error (RMSE) of the PLSR models obtained using soil impedance data. various PLS analysis. Based on the PLSR analysis, it would be concluded that the optimal spectrum measurement range was $32.0{\sim}50.0\;MHz$ with the optimal sub-spectrum size of about 18.5 MHz.