• Title, Summary, Keyword: homogeneous extension

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A Mathematical Model and an Algorithm for Dimensioning Problem of B-ISDN Extension (B-ISDN 확장 시 링크용량 설계 모형 및 알고리듬에 관한 연구)

  • 주종혁
    • Journal of the Society of Korea Industrial and Systems Engineering
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    • v.24 no.62
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    • pp.11-20
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    • 2001
  • At the initial deployment of B-ISDN, the heterogeneity of services and the bandwidth requirement make dimensioning of B-ISDN much more complicated than the dimensioning of homogeneous circuit or packet switched networks. Therefore B-ISDN must be extended gradually according to future telecommunication technology or service demands. In this paper, we propose a mathematical formulation for dimensioning problem of B-ISDN extension, considering the characteristics of ATM(Asynchronous Transfer Mode) such as various quality of services, the statistical multiplexing effects of VPCs(Virtual Path Connections) and the modularity of transmission links allocated when new B-ISDN nodes are given. The algorithm based on the simultaneous linear approximation technique and Lagrangian relaxation method and some numerical results are also presented.

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A bivariate extension of the Hosking and Wallis goodness-of-fit measure for regional distributions

  • Kjeldsen, Thomas Rodding;Prosdocimi, Ilaria
    • Proceedings of the Korea Water Resources Association Conference
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    • pp.239-239
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    • 2015
  • This study presents a bivariate extension of the goodness-of-fit measure for regional frequency distributions developed by Hosking and Wallis [1993] for use with the method of L-moments. Utilising the approximate joint normal distribution of the regional L-skewness and L-kurtosis, a graphical representation of the confidence region on the L-moment diagram can be constructed as an ellipsoid. Candidate distributions can then be accepted where the corresponding the oretical relationship between the L-skewness and L-kurtosis intersects the confidence region, and the chosen distribution would be the one that minimises the Mahalanobis distance measure. Based on a set of Monte Carlo simulations it is demonstrated that the new bivariate measure generally selects the true population distribution more frequently than the original method. An R-code implementation of the method is available for download free-of-charge from the GitHub code depository and will be demonstrated on a case study of annual maximum series of peak flow data from a homogeneous region in Italy.

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Energy release rate for kinking crack using mixed finite element

  • Salah, Bouziane;Hamoudi, Bouzerd;Noureddine, Boulares;Mohamed, Guenfoud
    • Structural Engineering and Mechanics
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    • v.50 no.5
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    • pp.665-677
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    • 2014
  • A numerical method, using a special mixed finite element associated with the virtual crack extension technique, has been developed to evaluate the energy release rate for kinking cracks. The element is two dimensional 7-node mixed finite element with 5 displacement nodes and 2 stress nodes. The mixed finite element ensures the continuity of stress and displacement vectors on the coherent part and the free edge effect. This element has been formulated starting from a parent element in a natural plane with the aim to model different types of cracks with various orientations. Example problems with kinking cracks in a homogeneous material and bimaterial are presented to assess the computational accuracies.

SONOGRAPHIC FINDING OF MAXILLOFACIAL MASS (악안면 종창에 대한 초음파 소견)

  • Kim, Hyoun-Tae
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.14 no.1_2
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    • pp.143-145
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    • 1992
  • Fourteen masses in the maxillofacial areas which are not diagnosised simply as abscess were studied with ultrasound to evaluate its diagnostic role. Benign mass showed homogeneous echopattern with smooth margin and cyst a few internal echo with smooth margin. But malignant mass showed irregular margin, inhomogeneous echotexture and deep extension. Ultrasonography considered as an initial noninvasive imaging modality for the evaluation of maxillofacial masses.

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A CHARACTERIZATION OF ELLIPTIC HYPERBOLOIDS

  • Kim, Dong-Soo;Son, Booseon
    • Honam Mathematical Journal
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    • v.35 no.1
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    • pp.37-49
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    • 2013
  • Consider a non-degenerate open convex cone C with vertex the origin in the $n$2-dimensional Euclidean space $E^n$. We study volume properties of strictly convex hypersurfaces in the cone C. As a result, for example, if the volume of the region of an elliptic cone C cut off by the tangent hyperplane P of M at $p$ is independent of the point $p{\in}M$, then it is shown that the hypersurface M is part of an elliptic hyperboloid.

Kinematics of filament stretching in dilute and concentrated polymer solutions

  • McKinley, Gareth H.;Brauner, Octavia;Yao, Minwu
    • Korea-Australia Rheology Journal
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    • v.13 no.1
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    • pp.29-35
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    • 2001
  • The development of filament stretching extensional rheometers over the past decade has enabled the systematic measurement of the transient extensional stress growth in dilute and semi-dilute polymer solutions. The strain-hardening in the extensional viscosity of dilute solutions overwhelms the perturbative effects of capillarity, inertia & gravity and the kinematics of the extensional deformation become increasingly homogeneous at large strains. This permits the development of a robust open-loop control algorithm for rapidly realizing a deformation with constant stretch history that is desired for extensional rheometry. For entangled fluids such as concentrated solutions and melts the situation is less well defined since the material functions are governed by the molecular weight between entanglements, and the fluids therefore show much less pronounced strain-hardening in transient elongation. We use experiments with semi-dilute/entangled and concentrated/entangled monodisperse polystyrene solutions coupled with time-dependent numerical computations using nonlinear viscoelastic constitutive equations such as the Giesekus model in order to show that an open-loop control strategy is still viable for such fluids. Multiple iterations using a successive substitution may be necessary, however, in order to obtain the true transient extensional viscosity material function. At large strains and high extension rates the extension of fluid filaments in both dilute and concentrated polymer solutions is limited by the onset of purely elastic instabilities which result in necking or peeling of the elongating column. The mode of instability is demonstrated to be a sensitive function of the magnitude of the strain-hardening in the fluid sample. In entangled solutions of linear polymers the observed transition from necking instability to peeling instability observed at high strain rates (of order of the reciprocal of the Rouse time for the fluid) is directly connected to the cross-over from a reptative mechanism of tube orientation to one of chain extension.

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NORMAL SYSTEMS OF COORDINATES ON MANIFOLDS OF CHERN-MOSER TYPE

  • Schmalz, Gerd;Spiro, Andrea
    • Journal of the Korean Mathematical Society
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    • v.40 no.3
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    • pp.461-486
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    • 2003
  • It is known that the CR geometries of Levi non-degen-erate hypersurfaces in $\C^n$ and of the elliptic or hyperbolic CR submanifolds of codimension two in $\C^4$ share many common features. In this paper, a special class of normalized coordinates is introduced for any CR manifold M which is one of the above three kinds and it is shown that the explicit expression in these coordinates of an isotropy automorphism $f{\in}Aut(M)_o {\subset}Aut(M),\;o{\in}M$, is equal to the expression of a corresponding element of the automorphism group of the homogeneous model. As an application of this property, an extension theorem for CR maps is obtained.

Extension of Rational Interpolation Functions for FE Analysis of Rotating Beams (회전하는 보의 유한요소해석을 위한 유리형상함수의 확장)

  • Kim, Yong-Woo;Jeong, Jae-Ho
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.19 no.6
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    • pp.591-598
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    • 2009
  • Starting from the rotating beam finite element in which the interpolating shape functions satisfy the governing static homogeneous differential equation of Euler-Bernoulli rotating beams, we derived new shape functions that satisfy the governing differential equation which contains the terms of hub radius and setting angle. The shape functions are rational functions which depend on hub radius, setting angle, rotational speed and element position. Numerical results for uniform and tapered cantilever beams with and without hub radius and setting angle are compared with the available results. It is shown that the present element offers an accurate method for solving the free vibration problems of rotating beams.

An Emission Characteristics of a Controlled Auto-Ignition Gasoline Engine (제어자발화 가솔린기관의 배기 특성)

  • Kim, H.S.
    • Journal of the Korea Society For Power System Engineering
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    • v.13 no.3
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    • pp.5-10
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    • 2009
  • This work deals with a controlled auto-ignition (CAI) single cylinder gasoline engine, focusing on the extension of operating conditions. The fuel is injected indirectly into electrically heated inlet air flow. In order to keep a homogeneous air-fuel mixing, the fuel injector is cooled by the water of a specially designed coolant passage. The engine emission characteristics were investigated under the wide range of operating conditions such as 32 to 63 in the air-fuel ratio, 1000 to 1800 rpm in the engine speed, and 150 to $180^{\circ}C$ in the inlet air temperature. The ultra lean-burn can be achieved by the auto-ignition of gasoline fuel due to the heated inlet air in the compression ignition gasoline engine. It is confirmed that the emission concentrations of carbon monoxide, hydrocarbons and nitrogen oxide can be significantly reduced by CAI combustion compared with the combustion of a conventional spark ignition engine.

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A Study on the Immateriality in Contemporary Interior Space (현대 실내공간에서의 비물질적 특성에 관한 연구)

  • 신홍경;옥창수
    • Korean Institute of Interior Design Journal
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    • v.13 no.3
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    • pp.76-83
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    • 2004
  • Nowadays, our societies use digital technology in new architectural shape and space design to transcend three dimension limit so the boundary of the imagination world and actuality world has been collapsed. Traditional spatial value has been collapsed. Also indetermination and temporary assumption in time, fluidness and dematerialized, simultaneity and reiteration in image are relative with this circumstances. In architectural shape, media characteristics which secede from traditional characteristics of place tectonic value have occurred. Therefore, indifference and interests in shape, inter-permeation in interior and exterior space, homogeneous equivalence spatial extension have occurred. The purpose in this study examines dematerialized in contemporary space design and light materials and also investigates general and architectural background. The results of this study are as follows. First, circumstances of human have changed from physically limited boundary to unfixed, nonphysical, lightness and vague things. Second, casting off volume in shape and also dissembling exclusive and constructive Third, interior and exterior space by transparency intimates media possibility of information screen. Fourth, seek information and organic response, ambivalent transformation, accumulation of image and new mutual understanding system.