• Title, Summary, Keyword: Logarithmic transformation

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A brief study on the geometric mean (기하평균에 대한 소고)

  • Yeo, In-Kwon
    • The Korean Journal of Applied Statistics
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    • v.33 no.4
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    • pp.357-364
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    • 2020
  • We review the characteristics of a geometric mean and statistical inferences based on geometric means. We also show that the statistical results obtained by the logarithmic transform and back-transformation are related to geometric means and explain how to interpret the results produced in this process.

Vector decomposition of the evolution equations of the conformation tensor of Maxwellian fluids

  • Cho, Kwang-Soo
    • Korea-Australia Rheology Journal
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    • v.21 no.2
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    • pp.143-146
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    • 2009
  • Breakthrough of high Weisenberg number problem is related with keeping the positive definiteness of the conformation tensor in numerical procedures. In this paper, we suggest a simple method to preserve the positive definiteness by use of vector decomposition of the conformation tensor which does not require eigenvalue problem. We also derive the constitutive equation of tensor-logarithmic transform in simpler way than that of Fattal and Kupferman and discuss the comparison between the vector decomposition and tensor-logarithmic transformation.

Estimation of Proportional Control Signal from EMG (EMG 신호에서의 비례제어신호 추정에 관한 연구)

  • Choi, Kwang-Hyeon;Byun, Youn-Shik;Park, Sang-Hui
    • Journal of Biomedical Engineering Research
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    • v.5 no.2
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    • pp.133-142
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    • 1984
  • The EMG signal can be considered as a signal source that expresses the intention of man because it is a electrical signal generated when the man contracts muscles. For proportional control of prostheses, the control signal proportional to the mousle contraction level must be estimated. Typically a foul-wave rectifier and low-pass filter are used to estimate the proportional control signal from the EMG signal. In this paper, it is proposed to use a logarithmic transformation and a linear minimum mean square error estimator. A logarithmic transformation maps the myoelectric signal into an additive control signal-plus-noise domain and the Kalman filter is used to estimate the control signal as a linear minimum mean square error estimator. The performance of this estimator is verified by the computer simulation and the estimator is applied to the EMG obtained from the biceps brachii muscle of normal subjects.

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Flood Frequency Analysis by the Box-Cox Transformation

  • 이순혁;조성갑;박명곤
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.32 no.E
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    • pp.20-32
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    • 1990
  • Abstract This study was conducted to pursue the normalization of frequency distribution by making an approach to the coefficient of skewness to nearly zero through the Box-Cox transformation, to get probable flood flows can be calculated by means of the transformation equation which has been derivated by Box-Cox transformation in the annual maximum series of the applied watersheds. It has been concluded that Box-Cox transfromation is proved to be more efficient than logarithmic, square root and SMEMAX transformation which is based on the trigonometric solution of a right triangle whose three verteces repesent the smallest, median and largest observed values of a population in making the coefficient of skewness nearer to zero. Consequently it is shown that probable flood flows according to the return period based on Box-Cox transformation are closer to the observed data as compared to other methods including SMEMAX transformation and fitted probability distributions such as the three parameter lognormal and the type I extremal distribution for the applied watersheds.

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Optimum Conditions for Transformation of Synechocystis sp. PCC 6803

  • Zang, Xiaonan;Liu, Bin;Liu, Shunmei;Arunakumara, K.K.I.U.;Zhang, Xuecheng
    • Journal of Microbiology
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    • v.45 no.3
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    • pp.241-245
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    • 2007
  • This study was conducted to determine the optimal conditions for introduction of exogenous DNA into Synechocystis sp. PCC 6803. Of the three transformation techniques studied, electroporation, ultrasonic transformation and natural transformation, natural transformation showed the highest efficiency. Additionally, this study demonstrated that the higher plasmid concentration and longer homologous recombining fragments resulted in a greater number of transformants. For successful transformation, the lowest concentration of plasmid was $0.02\;{\mu}g/ml$, and the shortest homologous recombining fragment was 0.2 kb. Use of Synechocystis sp. PCC 6803 in the logarithmic growth phase resulted in two-fold higher transformation rate than that of the same organism when cells in the latent phase or the plateau phase were used for transformation. Pretreatment of the host strain, Synechocystis sp. PCC 6803, with EDTA (2 mM) for two days prior to transformation increased the transformation efficiency by 23%. Additionally, incubation of the cells and DNA for 5 h under light conditions increased the transformation efficiency by two orders of magnitude. Moreover, recovery treatment of the cells before they were plated onto antibiotic medium also increased the transformation efficiency.

A Software Reliability Growth Model Based on Gompertz Growth Curve (Gompertz 성장곡선 기반 소프트웨어 신뢰성 성장 모델)

  • Park Seok-Gyu;Lee Sang-Un
    • The KIPS Transactions:PartD
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    • v.11D no.7
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    • pp.1451-1458
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    • 2004
  • Current software reliability growth models based on Gompertz growth curve are all logarithmic type. Software reliability growth models based on logarithmic type Gompertz growth curve has difficulties in parameter estimation. Therefore this paper proposes a software reliability growth model based on the logistic type Gompertz growth curie. Its usefulness is empirically verified by analyzing the failure data sets obtained from 13 different software projects. The parameters of model are estimated by linear regression through variable transformation or Virene's method. The proposed model is compared with respect to the average relative prediction error criterion. Experimental results show that the pro-posed model performs better the models based on the logarithmic type Gompertz growth curve.

Genetic Transformation of Bacillus subtilis by the Bacteriolytic Enzyme from Alkafophilic Bacillus sp. (호알칼리성 Bacillus sp.가 생산되는 Bacteriolytic Enzyme을 이용한 Bacillus subtilis의 형질전환)

  • 유주현;이인숙;옥승호;박희경;염도영;배동훈
    • Microbiology and Biotechnology Letters
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    • v.21 no.5
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    • pp.453-460
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    • 1993
  • The extracellular bacteriolytic enzyme from alkalophilic Bacillus sp. YJ-451 was endopeptidase which hydrolyzes the peptide bond at the amino group of D-glutamic acid in the peptidoglycan. Protoplast transfomation system of B. subtilis by the lytic enzyme that differs, in mechanisms, from lysozyme which was used to transformation of B. subtilis was investigated. High protoplast yield was obtained from cells cultured in PAB at the late logarithmic growth phase.

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Parametric Sensitivity Analysis Using Fourier Transformation (푸리에 변환을 이용한 파라미터 민감도 해석)

  • Baek, Moon-Yeal;Lee, Kyo-Seung
    • Journal of the Korea Society For Power System Engineering
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    • v.9 no.4
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    • pp.58-64
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    • 2005
  • 주파수 영역 민감도 해석법은 동적 시스템의 전달함수에 대한 설계 파라미터의 변화에 의한 효과를 파악하기 위해 사용되어 왔으며, 이때의 민감도 함수는 시스템 설계 파라미터에 대한 시스템 전달 함수의 편미분 값이다. 일반적으로 종래의 주파수 영역 민감도 해석은 직접 미분법이나 라플라스 변환이 사용되어 왔다. 라플라스 변환을 사용하는 경우에 시스템의 차수가 증가할수록 역행렬 조작은 매우 많은 시간을 필요로 하며 또한 어려운 작업이다. 본논문에서는 이러한 다점을 보완하기 위하여 푸리에변환을 이용한 민감도 기법을 제시하였다. 파라미터의 변화에 대한 진폭-주파수 특성의 민감도 해석을 간단한 2자유도 모델과 로터 다이나믹 시스템에 적용하였다.

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Deformation Invariant Optical Correlator Using Photorefractive Medium (광굴절 매질을 이용한 공간계 불변 광상관기에 관한 연구)

  • Kim, Ran-Sook;Ihm, Jong-Tae;Son, Hyon;Park, Han-Kyu
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.26 no.6
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    • pp.97-101
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    • 1989
  • Scale and rotation invariant polar-logarithmic coordinate transformation is used to achieve deformation invariant pattern recognition. The coordinate transformation is produce by a computer generated hologram (CGH). The mask fabricated by a photo (UV light) pattern generator for the 1nr-$theta$ coordinate transformation is made of the CGH whose transmission function is derived by the use of Lee's method. The optically produced coordinate transformed function is derived by the use of Lee's method. The optically produced coordinate transmission input pattern is interfaced on real-time holography. Variations of autocorrelation for scaled and rotated input patterns are suggested experimentally using implemented optical correlator.

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