• Title/Summary/Keyword: isotropy

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Seismic Traveltime Tomography in Inhomogeneous Anisotropic Media (불균질 이방성 매질에서의 탄성파 주시 토모그래피)

  • Jeong, Chang-Ho;Suh, Jung-Hee
    • 한국지구물리탐사학회:학술대회논문집
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    • 2007.06a
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    • pp.209-214
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    • 2007
  • In Korean geology that crystalline rock is dominant, the properties of subsurface including the anisotropy are distributed complexly and changed abruptly. Because of such geological environments, cross-hole seismic traveltime tomography is widely used to obtain the high resolution image of the subsurface for the engineering purposes in the geotechnical sites. However, because the cross-hole tomography has a wide propagation angle coverage relatively, its data tend to include the seismic velocity anisotropy comparing with the surface seismic methods. It can cause the misinterpretation that the cross-hole seismic data including the anisotropic effects are analyzed and treated with the general processing techniques assuming the isotropy. Therefore, we need to consider the seismic anisotropy in cross-hole seismic traveltime tomography. The seismic anisotropic tomography algorithm, which is developed for evaluation of the velocity anisotropy, includes several inversion schemes in order to make the inversion process stable and robust. First of all, the set of the inversion parameters is limited to one slowness, two ratios of slowness and one direction of the anisotropy symmetric axis. The ranges of the inversion parameters are localized by the pseudo-beta transform to obtain the reasonable inversion results and the inversion constraints are controlled efficiently by ACB(Active Constraint Balancing) method. Especially, the inversion using the Fresnel volume is applied to the anisotropic tomography and it can make the anisotropic tomography more stable than ray tomography as it widens the propagation angle coverage.

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Task Based Design of a Two-DOF Manipulator with Five-Bar Link Mechanism (5절 링크구조를 갖는 2자유도 매니퓰레이터의 작업지향설계)

  • Kim, Jin-Young;Cho, Hyung-Suck
    • Journal of Institute of Control, Robotics and Systems
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    • v.6 no.1
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    • pp.66-72
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    • 2000
  • As the demand for the design of modular manipulators or special purpose manipulators has increased, task based design to design an optimal manipulator for a given task become more and more important. However, the complexity with a large number of design parameters, and highly nonlinear and implicit functions are characteristics of a general manipulator design. To achieve the goal of task based design, it is necessary to develop a methodology to solve the complexity. This paper addresses how to determine the kinematic parameters of a two-degrees of freedom manipulator with parallelogram five-bar link mechanism from a given task, namely, how to map a given task into the kinematic parameters. With simplified example of designing a manipulator with five-bar link mechanism, the methodology for task based design is presented. And it introduces formulations of a given task and manipulator specifications, and presents a new dexterity measure for manipulator design. Also the optimization problem with constraints is solved by using a genetic algorithm that provides robust search in complex spaces.

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SCALAR CURVATURES ON SU(3)/T(k, l)

  • Pyo, Yong-Soo;Shin, Hyun-Ju;Park, Joon-Sik
    • Honam Mathematical Journal
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    • v.33 no.4
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    • pp.547-556
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    • 2011
  • In this paper, we estimated the Ricci curvature and the scalar curvature on SU(3)/T (k, l) under the condition (k, l) ${\in}\mathbb{R}^2$ (${\mid}k{\mid}+{\mid}l{\mid}{\neq}0$), where the four isotropy irreducible representations in SU(3)/T (k, l) are, not necessarily, mutually equivalent or inequivalent.

EQUIVARIANT VECTOR BUNDLES OVER GRAPHS

  • Kim, Min Kyu
    • Journal of the Korean Mathematical Society
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    • v.54 no.1
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    • pp.227-248
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    • 2017
  • In this paper, we reduce the classification problem of equivariant (topological complex) vector bundles over a simple graph to the classification problem of their isotropy representations at vertices and midpoints of edges. Then, we solve the reduced problem in the case when the simple graph is homeomorphic to a circle. So, the paper could be considered as a generalization of [3].

Dynamic optimal design of an anthropomorphic robot manipulator (인체형 로봇 매니퓰레이터의 동역학적 최적설계)

  • 이상헌;이병주;광윤근
    • 제어로봇시스템학회:학술대회논문집
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    • 1994.10a
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    • pp.82-87
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    • 1994
  • In this study, dynamic optimal design far a two degree-of-freedom anthropomorphic robot module is performed. Several dynamic design indices associated with the inertia matrix and the inertia power array are introduced. Analysis for the relationship between the dynamic parameters and the design indices shows that trade-offs exist between the isotropy and the dynamic design indices related to the actuator size. A composite design index is employed to deal with multi-criteria based design with different weighting factors, in a systematic manner. We demonstrate the fact that dynamic optimization is another significant step to enhance the system performances, followed by kinematic optimization.

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Computer Simulation of Microstructure of Particle Sediment

  • Kim, Jong-Cheol;Keun Auh;David M. Martin
    • The Korean Journal of Ceramics
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    • v.5 no.1
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    • pp.30-34
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    • 1999
  • Particle settling behavior was studied by the computer simulation using simultaneous particle condensation and relaxation. This three-dimensional settling algorithm includes the estimation of powder sediment density. Density distribution through the powder sediment was compared and was agreed well with the experimental findings. Settling density depended strongly of the degree of particle relaxation. Sediment strength and isotropy also depended on the degree of particle relaxation. Sever particle bridging was found near sharp corners.

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AN ENERGY FUNCTION FOR TRANSVERSELY-ISOTROPIC ELASTIC MATERIAL AND THE PONYTING EFFECT

  • Akinola, Ade
    • Journal of applied mathematics & informatics
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    • v.6 no.3
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    • pp.873-884
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    • 1999
  • On the basis of the semi-linear material of John invoking the theory of homogenization for heterogeneous media and the theory of invariants for isotropic scalar functions an energy function is built for a transversely-isotropic medium in finite elastic deformation. The ponyting Effect for material in simple shear is reviewed for this case of transversal isotropy. It is shown that this effect is apprehended by the constructed energy function.

Optimal design of finger phalanges

  • Choi, H.R.;Chung, W.K.;Youm, Y.
    • 제어로봇시스템학회:학술대회논문집
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    • 1992.10b
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    • pp.360-365
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    • 1992
  • An optimal design method to determine the lengths of finger phalanges is proposed especially for anthropomorphic design. The quality of designs are quantified by several measures of global isotropy for design, Also, for an example, optimal design of two fingers is performed and the results are compared with the anatomical data.

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Resonance on a Uniaxial Substrate with a Superstrate-Loaded Ractangular Patch antenna (덮게층을 갖는 일축성 매질위의 패치안테나의 공진해석)

  • 장승호;윤중한;이화춘;최병하
    • Proceedings of the IEEK Conference
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    • 1999.06a
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    • pp.195-198
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    • 1999
  • Complex resonant frequency of on a uniaxial substrate with a superstrate-loaded microstrip structure is investigate. The study is performed by Galerkin’s method. The numerical convergence using sinusoidal basis function. Numerical results for the effects of anisotropy in the substrate, superstrate permittivity, in the complex resonant frequency of the rectangular microstrip structure are also presented. Half-power bandwidth are increased due to the positive uniaxial an isotropy and superstrate.

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COMPLEX SCALING AND GEOMETRIC ANALYSIS OF SEVERAL VARIABLES

  • Kim, Kang-Tae;Krantz, Steven G.
    • Bulletin of the Korean Mathematical Society
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    • v.45 no.3
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    • pp.523-561
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    • 2008
  • The purpose of this paper is to survey the use of the important method of scaling in analysis, and particularly in complex analysis. Applications are given to the study of automorophism groups, to canonical kernels, to holomorphic invariants, and to analysis in infinite dimensions. Current research directions are described and future paths indicated.