• Journal of the Korean Data and Information Science Society
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• 제23권4호
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• pp.797-805
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• 2012

Many circular distributions are known to be not only asymmetric but also bimodal. Hidden truncation method of generating asymmetric distribution is applied to a bivariate circular distribution to generate an asymmetric circular distribution. While many other existing asymmetric circular distributions can only model an asymmetric data, this new circular model has great flexibility in terms of asymmetry and bi-modality. Some properties of the new model, such as the trigonometric moment generating function, and asymptotic inference about the truncation parameter are presented. Simulation and real data examples are provided at the end to demonstrate the utility of the novel distribution.

• Journal of the Korean Data and Information Science Society
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• 제22권6호
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• pp.1217-1222
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• 2011

In this paper, we show that any circular density can be closely approximated by an exponential family of distributions. Therefore we propose an exponential family of distributions as a new family of circular distributions, which is absolutely suitable to model any shape of circular distributions. In this family of circular distributions, the trigonometric moments are found to be the uniformly minimum variance unbiased estimators (UMVUEs) of the parameters of distribution. Simulation result and goodness of fit test using an asymmetric real data set show usefulness of the novel circular distribution.

• Structural Engineering and Mechanics
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• 제85권5호
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• pp.645-654
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• 2023

Based on first-order shear deformation theory, a wave propagation model of graphene platelets reinforced metal foams (GPLRMFs) circular plates is built in this paper. The expressions of phase-/group- velocities and wave number are obtained by using Laplace integral transformation and Hankel integral transformation. The effects of GPLs pattern, foams distribution, GPLs weight fraction and foam coefficient on the phase and group velocity of GPLRMFs circular plates are discussed in detail. It can be inferred that GPLs distribution have great impacts on the wave propagation problems, and Porosity-I type distribution has the largest phase velocity and group velocity, followed by Porosity-III, and finally Porosity-II; With the increase of the GPLs weight fraction, the phase- and group- velocities for the GPLRMFs circular plate will be increased; With the increase of the foam coefficient, the phase- and group- velocities for the GPLRMFs circular plate will be decreased.

• Communications for Statistical Applications and Methods
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• 제2권2호
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• pp.166-175
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• 1995

When a neutral particle beam(NPB) aimed at the object and receive a small number of neutron signals at the detector without any errors, it obeys Poisson law. Under the two assumptions that neutral particle scattering distribution and aiming errors have a circular Gaussian distributions that neutral particle scattering distribution and aiming errors have a circular Gaussian distribution respectively, an exact probability distribution of neutral particles vecomes a Poisson-power function distribution. We study and prove some properties, such as limiting distribution, unimodality, stochastical ordering, computational recursion fornula, of this distribution. We also prove monotone likelihood ratio(MLR) property of this distribution. Its MLR property can be used to find a criteria for the hypothesis testing problem.

• Communications for Statistical Applications and Methods
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• 제14권3호
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• pp.517-530
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• 2007

We studied a modelling process for unimodal and multimodal circular data by using von Mises and its mixture distribution. In particular we suggested EM algorithm to find ML estimates of the mixture model. Simulation results showed the suggested methods are very accurate. Applications to two kinds of real data sets are also included.

• 대한교통학회지
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• 제25권4호
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• pp.109-121
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• 2007

자료결측의 심각성은 현실적으로 거의 대부분의 조사에서 발생한다. 비단 교통분야뿐만 아니라 인문사회 분야나 기상학, 생물학, 지구과학 등 모든 분야에서 인력식이든 기계식이든 조사 방식에 관계없이 발생한다. 교통자료 수집장비에서의 자료결측의 발생은 현실적으로 불가피한 현상으로 볼 수 있으며, 이와 같은 자료 수집과정에서 발생하는 결측을 신뢰성있게 추정하여 보정하였던 선행연구의 대부분은 교통량 자료의 결측값 보정시 통계적 검증없이 시간적인 임의의 종속성만 고려함으로서, 보정 성능이 떨어지는 단점을 노출하고 있다. 이들 연구에서 적용했던 기법들 또한, 교통량 자료가 가지고 있는 가장 큰 특징인 주기적 순환성(periodic circularity)이 제대로 반영되지 못함으로서 적용상 한계를 노출하고 있다. 본 연구는 현실적으로 거의 대부분의 조사과정에서 발생하는 자료결측의 심각성에 대한 인식을 토대로 대안으로 순환분포모형을 제안하였다. 이러한 자료결측 현상에 대응하고자 하였던 기존의 ad-hoc 또는 heuristic 보정 기법과 모형 기반 및 알고리즘 기반의 보정 기법에 관한 선행 연구의 고찰을 통하여 이들 기법들의 한계점을 확인하였다.

• The Journal of Advanced Prosthodontics
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• 제5권4호
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• pp.434-439
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• 2013

PURPOSE. The aim of the present study was to evaluate the effects of posts with different morphologies on stress distribution in an endodontically treated mandibular premolar by using finite element models (FEMs). MATERIALS AND METHODS. A mandibular premolar was modeled using the ANSYS software program. Two models were created to represent circular and oval fiber posts in this tooth model. An oblique force of 300 N was applied at an angle of $45^{\circ}$ to the occlusal plane and oriented toward the buccal side. von Mises stress was measured in three regions each for oval and circular fiber posts. RESULTS. FEM analysis showed that the von Mises stress of the circular fiber post (426.81 MPa) was greater than that of the oval fiber post (346.34 MPa). The maximum distribution of von Mises stress was in the luting agent in both groups. Additionally, von Mises stresses accumulated in the coronal third of root dentin, close to the post space in both groups. CONCLUSION. Oval fiber posts are preferable to circular fiber posts in oval-shaped canals given the stress distribution at the postdentin interface.

• Steel and Composite Structures
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• 제49권6호
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• pp.713-728
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• 2023

This paper aims to investigate the free vibration analysis of FG plates, taking into account the effects of even and uneven porosity. The study employs the Hellinger-Reisner functional and obtains the element's bending stress and membrane stress fields from the analytical solution of the governing equations of the thick plate and plane problem, respectively. The displacement field serves as the second independent field. While few articles on free vibration analysis of circular plates exist, this paper investigates the free vibration of both rectangular and circular plates. After validating the proposed element, the paper investigates the effects of porosity distributions on the natural frequency of the FG porous plate. The study calculates the natural frequency of thin and thick bending plates with different aspect ratios and support conditions for various porosity and volume fraction index values. The study uses three types of porosity distributions, X, V, and O, for the uneven porosity distribution case. For O and V porosity distribution modes, porosity has a minor effect on the natural frequency for both circular and rectangular plates. However, in the case of even porosity distribution or X porosity distribution, the effect of porosity on the natural frequency of circular and rectangular plates increases with an increase in the volume fraction index.

• Applied Microscopy
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• 제18권2호
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• pp.167-176
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• 1988

Extrachromosomal circular DNA complexes from erythrocytes and splenocytes isolated from Carassius carassius were examined by mica-press-absorption method. The method was described that released small polydisperse circular DNA molecules in situ from the erythrocytes and the splenocytes and that allows selective observation of the small circular DNA complexes bound to cellular components. The released polydisperse circular DNA complexes were absorbed preferentially on mica in a divalent cation-free medium then processed for electron microscopy. Small circular DNAs showed a heterogeneous size distribution of $2{\sim}10{\mu}m$ with a mean contour length of $4.3{\mu}m$ for the circulating erythrocytes and that of $0.7{\sim}3.6{\mu}m$ with a mean contour of length $2.04{\mu}m$ for the splencytes. Cells contained $100{\sim}300$ copies and $300{\sim}700$ copies obtained from the erythrocytes and the splenocytes, repectively. Possible biological functional implications for size distribution of extrachromosomal circular DNAs are discussed.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 1999년도 추계학술발표대회 논문집
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• pp.223-226
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• 1999

This paper presents the theoretical analysis method to determine the stress concentrations around the circular cutouts with various geometrical parameters. The purposes of this study are to investigate on the stress distribution around the circular cutouts due to interaction between two circular cutouts and to develop the design method in composite plates. The composite laminated plate with 2 equal collinear circular cutouts under inplane loads is treated as an quasi-isotropic, symmetric, finite, square, multiply connected and thin plate. The effects of cutout sizes, distances between two circular cutouts and inplane load conditions on stress distribution are studied in detail.