• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.6B
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• pp.1106-1113
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• 2000

In this, paper, a DFT based polyphase filter bank for the fractional ratio oversampling is proposed. Proper fractional oversampling ratio gives lower aliasing than the critical sampling and, at the same time, lower computational load than the integer ratio oversampling. In addition, filter bank design becomes easier by the reduced aliasing effect of fractional ratio oversampling. Proposed fractional ratio oaversampling polyphase structure is applied to a subband adaptive filter for acoustic echo cancellation where long adaptive filter are ofter required. Echo cancellation results show that fractional ratio oversampling gives comparable performance to the integer ratio oversampling with less computational load.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.9
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• pp.454-459
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• 2003

Conventional integral-slot design in permanent magnet(PM) motor tends to have a high cogging torque and large end turns, which contribute to copper losses. The fractional-slot design is effective compared to integral-slot design in the cogging torque and electromotive force(EMF) waveform. The effectiveness of fractional slot can be maximized by selecting optimal pole to slot ratio. This paper presents the effect of pole to slot ratio on the cogging torque and EMF waveform in the PM motor with fractional-slot. The effectiveness of the proposed designs has been confirmed by comparing waveform of EMF. cogging torque and torque ripple between conventional and new models.

• Journal of the Korean Statistical Society
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• v.27 no.4
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• pp.385-396
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• 1998

A computing method of fractional Bayes factor (FBF) for a point null hypothesis is explained. We propose alternative form of FBF that is the product of density ratio and a quantity using the generalized Savage-Dickey density ratio method. When it is difficult to compute the alternative form of FBF analytically, each term of the proposed form can be estimated by MCMC method. Finally, two examples are given.

• Journal of Korea Foundry Society
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• v.17 no.6
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• pp.598-607
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• 1997

Fractional melting process involves heating an alloy within its liquid-solid region simultaneously ejecting liquid from the solid-liquid mixture. The extent of the purification obtained is comparable to that obtained in multi-pass zone refining. The new fractional melting process in which centrifugal force was used for separating the liquid from the mixture has been developed and applied to the purification of the metallic grade. Refining ratio depends on partition ratio, cake wetness and diffusion in the solid, and it was controlled by various processing parameters such as rotating speed and heating rate. The new parameter called "refining partition coefficient" has been suggested to estimate the effects of processing variables on the refining ratio. Because major impurities in MG-silicon such as Fe, Al, Ni have a low segregation coefficient, good purification effect is expected. The results of refining MG-silicon(98%) showed that 3N-Si was obtained in refined solid of 50% of the original sample.

• Journal of the Korean Data and Information Science Society
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• v.17 no.2
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• pp.619-631
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• 2006

When X and Y have independent Poisson distributions, we develop a Bayesian one-sided testing procedures for the ratio of two Poisson means. We propose the objective Bayesian one-sided testing procedures for the ratio of two Poisson means based on the fractional Bayes factor and the intrinsic Bayes factor. Some real examples are provided.

• 한국데이터정보과학회:학술대회논문집
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• 2006.04a
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• pp.295-306
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• 2006

When X and Y have independent Poisson distributions, we develop a Bayesian one-sided testing procedures for the ratio of two Poisson means. We propose the objective Bayesian one-sided testing procedures for the ratio of two Poisson means based on the fractional Bayes factor and the intrinsic Bayes factor. Some real examples are provided.

• Journal of the Korean Data and Information Science Society
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• v.18 no.3
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• pp.833-845
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• 2007

When X and Y have independent exponential distributions, we develop a Bayesian testing procedure for the ratio of two quantiles under reference prior. The noninformative prior such as reference prior is usually improper which yields a calibration problem that makes the Bayes factor to be defined up to a multiplicative constant. So we develop a Bayesian testing procedure based on fractional Bayes factor and intrinsic Bayes factor. We show that the posterior density under the reference prior is proper and propose the Bayesian testing procedure for the ratio of two quantiles using fractional Bayes factor and intrinsic Bayes factor. Simulation study and a real data example are provided.

• Journal of Power Electronics
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• v.13 no.6
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• pp.1008-1015
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• 2013

By using fractional calculus and the circuit-averaging technique, the modeling and analysis of a Buck converter with fractional order inductor and fractional order capacitor in discontinuous conduction mode (DCM) operations is investigated in this study. The equivalent averaged circuit model of the fractional order Buck converter in DCM operations is established. DC analysis is conducted by using the derived DC equivalent circuit model. The transfer functions from the input voltage to the output voltage, the duty cycle to the output voltage, the input impedance, and the output impedance of the fractional order Buck converter in DCM operations are derived from the corresponding AC-equivalent circuit model. Results show that the DC equilibrium point, voltage ratio, and all derived transfer functions of the fractional order Buck converter in DCM operations are affected by the inductor order and/or capacitor order. The fractional order inductor and fractional order capacitor are designed, and PSIM simulations are performed to confirm the correctness of the derivations and theoretical analysis.

• Proceedings of the KIEE Conference
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• 2002.04a
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• pp.74-76
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• 2002

Conventional integral slot design tend to have a high cogging torque and large end turns which contribute to copper losses. The fractional slot is more effective compared to integral slot in the cogging torque and EMF waveform. The effectiveness of fractional slot can be maximized by selecting optimal pole to slot ratio. This paper presents the effect of pole to slot ratio on the cogging torque and EMF waveform in the fractional slotted permanent magnet(PM) motor. The effectiveness of the proposed designs had been confirmed by comparing cogging torque, and EMF waveform between conventional and new models which are analyzed by Finite Element Method(FEM).

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.1
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• pp.436-450
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• 2017

Recently, the method based on fractional order partial differential equation has been used in image processing. Usually, the optional order of fractional differentiation is determined by a lot of experiments. In this paper, a denoising model is proposed based on adaptive fractional order anisotropic diffusion. In the proposed model, the complexity of the local image texture is reflected by the local variance, and the order of the fractional differentiation is determined adaptively. In the process of the adaptive fractional order model, the discrete Fourier transform is applied to compute the fractional order difference as well as the dynamic evolution process. Experimental results show that the peak signal-to-noise ratio (PSNR) and structural similarity index measurement (SSIM) of the proposed image denoising algorithm is better than that of other some algorithms. The proposed algorithm not only can keep the detailed image information and edge information, but also obtain a good visual effect.