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1

Integrated region-based segmentation using color components and texture features with prior shape knowledge

Emambakhsh M., Ebrahimnezhad H., Sedaaghi M. H.

International Journal of Applied Mathematics and Computer Science

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2010

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Vol. 20, no 4

711-726

EN

Segmentation is the art of partitioning an image into different regions where each one has some degree of uniformity in its feature space. A number of methods have been proposed and blind segmentation is one of them. It uses intrinsic image features, such as pixel intensity, color components and texture. However, some virtues, like poor contrast, noise and occlusion, can weaken the procedure. To overcome them, prior knowledge of the object of interest has to be incorporated in a top-down procedure for segmentation. Consequently, in this work, a novel integrated algorithm is proposed combining bottom-up (blind) and top-down (including shape prior) techniques. First, a color space transformation is performed. Then, an energy function (based on nonlinear diffusion of color components and directional derivatives) is defined. Next, signeddistance functions are generated from different shapes of the object of interest. Finally, a variational framework (based on the level set) is employed to minimize the energy function. The experimental results demonstrate a good performance of the proposed method compared with others and show its robustness in the presence of noise and occlusion. The proposed algorithm is applicable in outdoor and medical image segmentation and also in optical character recognition (OCR).

2

Energia powierzchniowa, dyssypacja i efekty skali w modelowaniu mikrostruktur martenzytycznych

Petryk H., Stupkiewicz S.

Czasopismo Techniczne. Mechanika

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2010

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R. 107, z. 4-M

99-108

PL

W niniejszym artykule przedstawiono energetyczne podejście do wieloskalowego modelowania ewolucji mikrostruktur martenzytycznych w stopach z pamięcią kształtu. Energia swobodna Helmholtza i energia dyssypowana w układzie reprezentowane są przez sumy członów odpowiadających energii objętościowej oraz energii powierzchniowej na granicach mikro-strukturalnych pomiędzy poszczególnymi wariantami martenzytu, fazami lub ziarnami. Ewolucja mikrostruktury jest wyznaczana drogą przyrostowej minimalizacji całkowitej energii dostarczanej do rozpatrywanego układu w procesie makroskopowo quasi-statycznym i izotermicznym. Ogólną procedurę zastosowano do numerycznych symulacji powstawania i ewolucji warstwowych struktur martenzytycznych indukowanych naprężeniowo w stopach z pamięcią kształtu. W energii powierzchniowej uwzględniono energię mikroodkształceń sprężystych w otoczeniu granic mikrostrukturalnych, wyznaczoną przy użyciu metody elementów skończonych. Policzone przykłady opisują ewolucję mikrostruktury martenzytycznej w formie laminatu trzeciego rzędu w stopie CuAlNi dla przemiany 1 1 [beta]-->[gamma]' oraz jej zależność od sposobu uwzględnienia dyssypacji energii powierzchniowej.

EN

The energy approach to multiscale modelling of evolution of martensitic microstructures in shape memory alloys (SMA) is presented. Both the Helmholtz free energy and the energy dissipated in the system comprise the usual bulk energy contributions as well as the interfacial energy terms corresponding to different scales, namely martensite-martensite, austenite-martensite and grain boundaries. Microstructure evolution is determined by incremental minimization of the energy supplied to the system in a macroscopically quasi-static and isothermal process. As an application of the general approach, the formation and evolution of stress-induced laminated microstructures in SMA has been studied. The interfacial energy of elastic micro-strains at microstructured interfaces has been estimated using the finite element method. Evolution of a rank-three laminated microstructure in a C uAlNi alloy undergoing the 1 1 [beta]-->[gamma]' transformation has been determined, showing the effect of size-dependent dissipation related to the release of interfacial energy.

3

Dissipated energy minimization in a combustion engine mount system by position dependent damping coefficients

Lipiński K., Kneba Z.

Vibrations in Physical Systems

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2008

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Vol. 23

241--246

EN

Multibody modelling of a combustion engine is presented in the paper. The engine’s vibrations are of primary interest as well as energy dissipated in the engine’s suspension. System’s excitation is proportional to engine’s rotational velocity, thus vibration’s amplitude converges to some constant, non-zero value for high rotational velocities. With the amplitude being constant, suspension’s dissipated energy grows significantly with the velocity. A method to reduce the energy is considered in the paper.