• Title/Summary/Keyword: von Mises 분포

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Quantification of Storm Direction for a River Basin (하천유역에 대한 호우 방향성의 정량화)

  • Park, Chang-Yeol;Yoo, Chul-Sang
    • Journal of the Korean Society of Hazard Mitigation
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    • v.10 no.6
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    • pp.109-117
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    • 2010
  • This study quantified the storm direction for a river basin by applying the von Mises distribution, also determined the representative storm direction. Additionally, the whole procedure was repeated for several storm types such as frontal, typhoon and convective storms for their comparison. From the results derived by analyzing a total of 101 storm events for the Naesung river basin, the von Mises distribution was found to explain the directional characteristics of storms. The representative moving directions derived for three different storm types were significantly different each other, which is coincident with the climate of Korea. The results derived in this study could be helpful to estimate more quantitatively the difference in the runoff response with respect to the moving direction of a storm.

Quantification of Directional Properties of Channel Network and Hill Slope (하천망과 사면의 방향성 정량화)

  • Park, Changyeol;Yoo, Chulsang
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.31 no.3B
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    • pp.233-242
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    • 2011
  • This study quantified directional properties of channel network and hill slope for a river basin by applying the von Mises distribution, also examined the relation between them. Ultimately, it was examined that whether the directional properties of channel network and hill slope have a certain relation, which might be considered to the rainfall-runoff modeling. From the results derived by analyzing the Naesung stream basin, the von Mises distribution was found well to explain the directional characteristics of directional properties of channel network. There was a clear relation between directional properties of channel network and hill slope. The higher-order streams also showed very obvious modal characteristics. The results derived in this study could be helpful to estimate more quantitatively the difference in the runoff response with respect to the directional properties of channel network and hill slope.

Modified Test Statistic for Identity of Two Distribution on Credit Evaluation (신용평가에서 두 분포의 동일성 검정에 대한 수정통계량)

  • Hong, C.S.;Park, H.S.
    • The Korean Journal of Applied Statistics
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    • v.22 no.2
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    • pp.237-248
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    • 2009
  • The probability of default on the credit evaluation study is represented as a linear combination of two distributions of default and non-default, and the distribution of the probability of default are generally known in most cases. Except the well-known Kolmogorov-Smirnov statistic for testing the identity of two distribution, Kuiper, Cramer-Von Mises, Anderson-Darling, and Watson test statistics are introduced in this work. Under the assumption that the population distribution is known, modified Cramer-Von Mises, Anderson-Darling, and Watson statistics are proposed. Based on score data generated from various probability density functions of the probability of default, the modified test statistics are discussed and compared.

Decision of the Representative Moving Direction of a Storm Event (호우사상의 대표 이동방향 결정)

  • Yoo, Chul-Sang;Park, Chang-Yeol
    • Journal of the Korean Society of Hazard Mitigation
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    • v.10 no.2
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    • pp.91-102
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    • 2010
  • This study analyzed methodologies for determining the representative direction of a storm event. The mean direction, median direction, and modal direction of von Mises distribution were considered as representative directions. In addition, the results with and without considering the storm moving distance were also compared. As results, the modal directions of von Mises distribution were found to explain the directional characteristics of a moving storm much better than other methods. Also, it was found that the storm moving distance has a significant effect on the determination of representative directions of a moving storm, whose uncertainty can also be decreased significantly by considering the moving distance.

Bone Mineral Density and Stress Distribution in Human Patella

  • Han, Seung-Moo;Jared Davis
    • Journal of Biomedical Engineering Research
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    • v.19 no.1
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    • pp.53-58
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    • 1998
  • This study examined the distribution of bone mineral density(BMD) and the von Mises stress in the patella. The BMD of eighteen patellae were determined by using quantitative computed tomography and imaging analysis software. It was found that the BMD of the patella varied with location. BMD values were largest at the superior and lateral regions and decreased inferiorly and medially. This distribution appeared to correspond to the organization of trabeculae within the patella. A two-dimensional finite element analysis was performed on each patella. It was also found that the maximum von Mises stress in the patella occurred along the cortical shell on the non-articular surface. The trabecular von Mises stress existed in the posterior region of the patella. These findings demonstrated the potential for finite element studies in vivo. Further, such studies may lead to the development of custom-made, patient-specific patella prostheses.

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EDF 통계량을 이용한 다변량 정규성 검정

  • Kim, Nam-Hyeon
    • Proceedings of the Korean Statistical Society Conference
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    • 2005.05a
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    • pp.31-36
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    • 2005
  • EDF에 근거한 Cramer-von Mises 형태의 통계량을 합교원리를 이용하여 다변량으로 일반화한다. 그리고 제안된 통계량의 귀무가설에서의 극한분포를 적절한 공분산함수를 가진 가우스 과정의 적분의 형태로 표현하고 통계량의 근사적인 계산방법을 고려한다.

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Testing Multivariate Normality Based on EDF Statistics (EDF 통계량을 이용한 다변량 정규성검정)

  • Kim Nam-Hyun
    • The Korean Journal of Applied Statistics
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    • v.19 no.2
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    • pp.241-256
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    • 2006
  • We generalize the $Cram{\acute{e}}r$-von Mises Statistic to test multivariate normality using Roy's union-intersection principle. We show the limit distribution of the suggested statistic is representable as the integral of a suitable Gaussian process. We also consider the computational aspects of the proposed statistic. Power performance is assessed in a Monte Carlo study.

Testing Exponentiality Based on EDF Statistics for Randomly Censored Data when the Scale Parameter is Unknown (척도모수가 미지인 임의중도절단자료의 EDF 통계량을 이용한 지수 검정)

  • Kim, Nam-Hyun
    • The Korean Journal of Applied Statistics
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    • v.25 no.2
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    • pp.311-319
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    • 2012
  • The simplest and the most important distribution in survival analysis is exponential distribution. Koziol and Green (1976) derived Cram$\acute{e}$r-von Mises statistic's randomly censored version based on the Kaplan-Meier product limit estimate of the distribution function; however, it could not be practical for a real data set since the statistic is for testing a simple goodness of fit hypothesis. We generalized it to the composite hypothesis for exponentiality with an unknown scale parameter. We also considered the classical Kolmogorov-Smirnov statistic and generalized it by the exact same way. The two statistics are compared through a simulation study. As a result, we can see that the generalized Koziol-Green statistic has better power in most of the alternative distributions considered.

A Simple Calculational Method by using Modified Von Mises Transformation applied to the Coaxial Turbulent Jet Mixing (유동함수를 이용한 난류제트혼합유동 계산에 관한 연구)

  • Choi Dong-Whan
    • Journal of the Korean Society of Propulsion Engineers
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    • v.9 no.2
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    • pp.97-104
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    • 2005
  • A simple but efficient grid generation technique by using the modified compressible form of stream function has been formulated. Transformation of a physical plane to a streamline plane, the Von Mises Transformation, has been widely used to solve the differential equations governing flow phenomena, however, limitation arises in low velocity region of boundary layer, mixing layer and wake region where the relatively large grid spacing is inevitable. Modified Von Mises Transformation with simple mathematical adjustment for the stream function is suggested and applied to solve the confined coaxial turbulent jet mixing with simple $\kappa-\epsilon$ turbulence model. Comparison with several experimental data of axial mean velocity, turbulent kinetic energy, and Reynolds shear stress distribution shows quite good agreement in the mixing layer except in the centerline where the turbulent kinetic energy distributions were somewhat under estimated. This formulation is strongly suggested to be utilized specially for free turbulent mixing layers in axisymmetric flow conditions such as the investigation of mixing behavior, jet noise production and reduction for Turbofan engines.

Direction Estimation of Multiple Sound Sources Using Circular Probability Distributions (순환 확률분포를 이용한 다중 음원 방향 추정)

  • Nam, Seung-Hyon;Kim, Yong-Hoh
    • The Journal of the Acoustical Society of Korea
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    • v.30 no.6
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    • pp.308-314
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    • 2011
  • This paper presents techniques for estimating directions of multiple sound sources ranging from $0^{\circ}$ to $360^{\circ}$ using circular probability distributions having a periodic property. Phase differences containing direction information of sources can be modeled as mixtures of multiple probability distributions and source directions can be estimated by maximizing log-likelihood functions. Although the von Mises distribution is widely used for analyzing this kind of periodic data, we define a new class of circular probability distributions from Gaussian and Laplacian distributions by adopting a modulo operation to have $2{\pi}$-periodicity. Direction estimation with these circular probability distributions is done by implementing corresponding EM (Expectation-Maximization) algorithms. Simulation results in various reverberant environments confirm that Laplacian distribution provides better performance than von Mises and Gaussian distributions.