• Journal of Magnetics
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• v.18 no.2
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• pp.197-201
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• 2013

This paper presents the conversion parameter values of the magnetic properties of magnetic fluids. These values were determined for three magnetic fluid samples containing particles with diameters between 30 ${\AA}$ and 170 ${\AA}$. The factors that may affect the value of this parameter (size of particle, magnetic properties, the presence of clusters and aggregates) are also studied. The determined values for the conversion parameter (${\gamma}$) are between 0.25 and 0.76 and the determined limit value is 0.8. Because many applications require magnetic fluids with the saturation magnetization as high as possible and the viscosity as low as possible [1], it has been considered necessary to determine this parameter which describes the quality of magnetic fluids.

• Journal of Advanced Navigation Technology
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• v.20 no.4
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• pp.361-366
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• 2016

This paper presents an arbitrary impedance transformer with unequal split, based on S- to admittance parameter conversion. When compared even/ odd- mode analysis, the parameter conversion design method constitutes a simple design method to include phase delay information and arbitrary port impedances and asymmetrical configurations. To validate this design method, we designed a 50 to $12.5{\Omega}$ impedance transformer with a 3:1 unequal power split, at an operating frequency of 1 GHz. To implement the proposed impedance transformer, the low impedance transmission lines of calculated result are fabricated by the transmission line connected shunt open stub. Good experimental performances were obtained, in full agreement with simulated results.

• Proceedings of the IEEK Conference
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• 2003.07e
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• pp.2228-2231
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• 2003

In this paper, a transcoding algorithm for the Selectable Mode Vocoder (SMV) and the G.723.1 speech coder via direct parameter transformation is proposed. In contrast to the conventional tandem transcoding algorithm, the proposed algorithm converts the parameters of one coder to the Other Without going through the decoding md encoding process. The proposed algorithm is composed of four parts: the parameter decoding, line spectral pair (LSP) conversion, pitch period conversion, excitation conversion and rate selection. The evaluation results show that the proposed algorithm achieves equivalent speech quality to that of tandem transcoding with reduced computational complexity and delay.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.40 no.6
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• pp.61-70
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• 2003

In this paper, a transcoding algorithm for the Selectable Mode Vocoder (SMV) and the G.723.1 speech coder via direct parameter transformation is proposed. In contrast to the conventional tandem transcoding algorithm, the proposed algorithm converts the parameters of one coder to the other without going through the decoding and encoding process. The proposed algorithm is composed of four parts: the parameter decoding, line spectral pair (LSP) conversion, pitch period conversion, excitation conversion and rate selection. The evaluation results show that the proposed algorithm achieves equivalent speech quality to that of tandem transcoding with reduced computational complexity and delay.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.6
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• pp.1105-1110
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• 2007

This paper describes an equivalent circuit modeling of 4-port connector system. A coupled transmission line was designed and fabricated, mimicking a 4-port connector system, and then S-parameters were measured using 4 port VNA (Vector Network Analyzer). The S-parameters from measurement and from Full-wave simulator coincided quite nice. By using these S parameters, an equivalent circuit parameters for a 4-port system was obtained. The time domain response from the equivalent circuit model matched to the signals, which was measured using TDR(Time Domain Reflectometry) meter. We were also convinced that there should be enough bandwidth to get a meaningful time domain result from Fourier inverse transformation of the S parameters. In addition, we applied the conversion algorithm to the 4-port connector system, which calculates the S-parameters of a 4 port system using the data from a 2-port VNA with the other ports open. Comparison of the two data, one from measurement and the other one from the conversion algorithm, was made in this manuscript.

• Journal of Electrical Engineering and Technology
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• v.13 no.6
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• pp.2329-2334
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• 2018

This paper discusses the thermal effect of the number of permanent-magnet (PM) layers in an outer rotor machine. Depending on the number of axial-layer of PM, the operating temperature is compared analytically and experimentally. The electromagnetic analysis is performed using 3-dimensional time varying finite element method to get the heat sources depending on axial-layered PM models. Then thermal analysis is conducted using the lumped-parameter-thermal-network method for each case. Two outer rotor machines, which have the different number of axial-layer of PM, are manufactured and tested to validate the analysis results.

• Journal of Power Electronics
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• v.14 no.4
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• pp.806-813
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• 2014

Planar electromagnetic interference (EMI) filters are widely used to restrain the conducted EMI of switching power supplies. Such filters are characterized by small size, low parasitic parameters, and better high-frequency performance than the passive discrete EMI filter. However, EMI filter performance cannot be exactly predicted by using existing methods. Therefore, this paper proposes a method to use scattering parameters (S-parameters) for the measurement of EMI filter performance. A planar EMI filter sample is established. From this sample, the relationship between S-parameters and insertion gain (IG) of EMI filter is derived. To determine the IG under different impedances, the EMI filter is theoretically calculated and practically measured. The differential structure of the near-field coupling model is also deduced, and the IG is calculated under standard impedance conditions. The calculated results and actual measurements are compared to verify the feasibility of the theory.

• Journal of Radiation Protection and Research
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• v.15 no.2
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• pp.101-112
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• 1990

For the performance assessment of the radioactive waste disposal system (repository), a biosphere model is suggested. This biosphere model is intended to calculate the annual doses to man caused by the contaminated river water for eight pathways and four radionuclides. This model can also be applied to assess the radiological effects of contaminated well water. To account for the uncertainties on the model parameter values, parameter distributions are assigned to these model parameters. Then, Monte Carlo simulation method with Latin Hypercube sampling technique is used. Also, sensitivity analysis is performed by using the Spearman rank correlation coefficients. It is found that these methods are a very useful tool to treat uncertainties and sensitivities on the model parameter values and to analyze the biosphere model. A conversion factor is proposed to calculate the annual dose rate to humans arising from a unit radionuclide concentration in river water. This conversion factor allows for the substitution of the biosphere model in a probabilistic performance assessment computer code by one single variable.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.40 no.6
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• pp.71-83
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• 2003

In this paper, a novel transcoding algorithm for the G.729A and the Selectable Mode Vocoder(SMV) vocoders via direct parameter transformation is proposed. In contrast to the conventional tandem transcoding algorithm, the proposed algorithm converts the parameters of one coder to the other without going through the decoding and encoding processes. In transcoder from SMV to G.729A, LSP conversion algorithm, pitch delay conversion algorithm and transcoding algorithm in lower rate are proposed, and in transcoder from G.729A to SMV, LSP conversion algorithm, pitch delay conversion algorithm and rate selection algorithm are proposed. Evaluation results show that while exhibiting better computational and delay characteristics, the proposed algorithm produces equivalent or Improved speech quality to that produced by the tandem transcoding algorithm.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.40 no.5
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• pp.322-331
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• 2003

Advances of high-definition television(HDTV) and personal computers call for the mutual conversion between interlaced signal and progressive signal. Especially, deinterlacing which is known as an interlaced to progressive conversion has been recently required and investigated. In this paper, we propose new deinterlacing algorithm considering sub-pixel motion information. In order to reduce the error of motion estimation, we analyze the effect of inaccurate sub-pixel motion information and model it as zero-mean Gaussian noises added respectively to each low resolution image(field). The error caused by inaccurate motion information is reduced by determining regularization parameter according to the error of motion estimation in each channel. The validity of the proposed algorithm is demonstrated both theoretically and experimentally in this paper.