• Progress in Superconductivity and Cryogenics
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• v.11 no.3
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• pp.31-34
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• 2009

An HTS power cable is generally composed of 2 layers for conducting and 1 layer for shielding. For the analysis of AC loss of an HTS power cable, 2-dimensional magnetic field analysis is carried out. The magnetization loss in HTS cable core was calculated, and the transport current loss was obtained from the monoblock equation and the elliptical Norris Equation. And the total AC loss of the cable was expected by the sum of magnetization loss and transport current loss. The variation of ac loss with respect to the gap and uncertain factor between the superconducting tapes was investigated, and the ac loss of 22.9kV/50MVA high-Tc superconducting power cable was calculated. These results well agree with those of experiment.

• Journal of Korea Water Resources Association
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• v.43 no.6
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• pp.533-541
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• 2010

It is basic for a flood prediction to calculate direct runoff from rainfall in a basin by the rainfall-runoff model. The direct runoff is calculated from rainfall excess or effective rainfall based on a rainfall-runoff model. The total rainfall minus rainfall loss equals rainfall excess with time. This loss can be treated equal to an infiltration loss under the assumption that the infiltration is a major one among the losses in the rainfall-runoff model. Practically obtaining the infiltration loss $\Phi$ index method, W index method or modified ones of these have been used. In this study it is assumed the loss of rainfall in a basin be a well-known Horton infiltration mechanism. And in case that the parameter set is given in the Horton infiltration model a procedure and assumption for calculating hourly infiltration loss and rainfall excess are offered and the results of its application are compared with those of $\Phi$ index method. By this study it is well shown the value of Horton infiltration function is exponentially decay with time as the Horton infiltration mechanism.

• Communications for Statistical Applications and Methods
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• v.21 no.3
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• pp.235-243
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• 2014

Constrained Bayesian estimates overcome the over shrinkness toward the mean which usual Bayes and empirical Bayes estimates produce by matching first and second empirical moments; subsequently, a constrained Bayes estimate is recommended to use in case the research objective is to produce a histogram of the estimates considering the location and dispersion. The well-known squared error loss function exclusively emphasizes the precision of estimation and may lead to biased estimators. Thus, the balanced loss function is suggested to reflect both goodness of fit and precision of estimation. In insurance pricing, the accurate location estimates of risk and also dispersion estimates of each risk group should be considered under proper loss function. In this paper, by applying these two ideas, the benefit of the constrained Bayes estimates and balanced loss function will be discussed; in addition, application effectiveness will be proved through an analysis of real insurance accident data.

• Journal of Electrical Engineering and Technology
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• v.9 no.6
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• pp.2013-2018
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• 2014

According to the manufacturing process of the laminated stator core for an inserted permanent magnet synchronous motor (IPMSM), the iron loss may be different. It is because the mechanical stress imposed to electrical steel sheet is strongly dependent on the manufacturing process. This paper proposes a new iron loss measurement algorithm which utilizes the induced voltage of a search coil and exciting current. The method is effective even when the distribution of magnetic flux density is not uniform along the magnetic flux path as well as uniform. The developed iron loss measurement system is applied to bonded- and embossed-type segmented stator cores of an IPMSM, and the iron losses are quantitatively compared.

• Journal of Magnetics
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• v.17 no.4
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• pp.280-284
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• 2012

This paper presents a method for evaluating interior permanent magnet synchronous motor (IPMSM) performance over the entire operation region. Using a d-q axis equivalent circuit model consisting of motor parameters such as the permanent magnetic flux, copper resistance, core loss resistance, and d-q axis inductance, a conventional mathematical model of an IPMSM has been developed. It is well understood that in IPMSMs, magnetic operating conditions cause cross saturation and that the iron loss resistance - upon which core losses depend - changes according to the motor speed; for the sake of convenience, however, d-q axis machine models usually neglect the influence of magnetic cross saturation and assume that the iron loss resistance is constant. This paper proposes an analysis method based on considering a magnetic cross saturation and estimating a core loss resistance that changes with the operating conditions and speed. The proposed method is then verified by means of a comparison between the computed and the experimental results.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.7
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• pp.79-87
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• 1997

Untill now, the most well-known cofiguration for waveguide grating router(WGR) is composed of radiative star couplers and arrayed waveguide grating(AWG), which usually suffer form the rdiation loss of around 3dB or more. Therefore, te improved design of WGRs is needed to reduce the loss. In ths paper, we propose a novel WGR composed of multimode interference couplers which have good unifiormity, fabrication tolerance, and very low excess loss, and suggest the efficient algorithm to find the proper path length differences of AWG for given channel spacing and channel assignment to each output prot. The simulated spectral responses of the proposed WGR using the finite difference beam propagation method (BPM) show that the excess loss is less than 0.3dB and the crosstalk less than -25dB in case of 4x4 WGR, and the excess loss less than 0.4dB and the crosstalk less than -25dB in case of 8x8 WGR for all the channel wavelengths.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.760-761
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• 2008

This paper deals with the core loss as well as torque characteristics according to the change of stator shape in an interior permanent magnet synchronous motor (IPMSM). The finite element method and functional core loss data obtained by the steinmetz equation are used in order to estimate the core loss. To minimize the core loss caused by the shape of tooth tip, slot-area and volume of permanent magnet, those are all the same in each model. In the end, the ratio between tooth width and yoke thickness to minimize the core loss in the IPMSM is presented in this paper.

• International Journal of Quality Innovation
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• v.6 no.2
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• pp.31-45
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• 2005

The target costing technique, mathematically discussed by Sauers, only uses the $C_p$ index along with Taguchi loss function and ${\bar{X}}-R$ control charts to set up goal control limits. The new specification limits derived from Taguchi loss function is linked through the $C_p$ value to ${\bar{X}}-R$ control charts to obtain goal control limits. This study further considers the reflected normal loss function as well as the $C_{pk}$ index along with its lower confidence interval in forming goal control limits. With the use of lower confidence interval to replace the point estimator of the $C_{pk}$ index and reflected normal loss function proposed by Spiring to measure the loss to society, this modified and improved target costing technique would become more robust and applicable in practice. Finally, an example is provided to illustrate how this modified and improved target costing technique works.

• Proceedings of the KIEE Conference
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• 2009.04b
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• pp.55-57
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• 2009

This paper deals with an improved core loss calculation under the load conditions, namely, no-load, AC-load and DC-load of multi-pole PM generator from curve fitting method using modified Steinmetz equation considered anomalous loss. For an accurate calculation, magnetic field analyses in stator core considering the time harmonics are performed. And using the nonlinear finite element analysis (FEA), we applied separated rotating and alternating magnetic field to core loss calculation. In order to verify the core loss results by proposed method, the experimental system for no-load core loss measurement has been implemented with DC motor, power analyzer and manufactured PM generator. And, the analysis results with rotational speed agree extremely well with those obtained by measurement.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.04a
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• pp.473-480
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• 1997

This paper presents the feasibility of the assumption that incident sound to panels might have a Gaussian distribution, instead of the well-known uniform distribution in the analysis of sound transmission loss of panels. Being compared with the latter, it seems that the former is physically more concrete. To prove the assumption, the problems with diffuse fields in reverberation room are considered by case study and comparisions of the prediction with the measurement of sound transmission loss of walls are performed. The results show good agreement between the two values.