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Computation of the filtration laws through porous media for a non-Newtonian fluid obeying the power law

Computational Geosciences 1997年第2期1卷 127-153页

作者： Gipouloux, Olivier Equipe d'Analyse Numerique UMR 5585 Universite de Saint Etienne F-42023 Saint Etienne Cedex 23 Rue du Docteur Michelon France

We consider a stationary flow of an incompressible non-Newtonian flow through a porous medium, induced by an injection velocity when inertial effects are negligible. At the pore scale, the governing equations are based on a nonlinear relation between the stress and the rate of deformation. In such a situation, the limit problem obtained when the pore size tends to zero, is called the homogenized problem that leads to the filtration law. This filtration law is given by a non-linear system coupling a local problem on a typical cell of the porous medium to a global problem at the scale of the whole porous medium. We propose, in this work, a numerical method to solve this homogenized problem and apply this method when the velocity dependent viscosity is given by the power law. Finally, we propose some numerical experiments to illustrate our approach. © Baltzer Science Publishers BV.

关键词： Filtration law Homogenization Non-Newtonian fluid numerical algorithm Porous medium Power law

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Image Enhancement with Applications in Biomedical Processing 3rd

Image Enhancement with Applications in Biomedical Processing

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3rd Conference on Information Technology, Systems Research and Computational Physics (ITSRCP)

作者： Charytanowicz, Malgorzata Kulczycki, Piotr Lukasik, Szymon Kowalski, Piotr A. Polish Acad Sci Syst Res Inst Ctr Informat Technol Data Anal Methods Newelska 6 PL-01447 Warsaw Poland Lublin Univ Technol Elect Engn & Comp Sci Fac Nadbystrzycka 36A PL-20618 Lublin Poland AGH Univ Sci & Technol Div Informat Technol & Biometr Fac Phys & Appl Comp Sci Mickiewicza 30 PL-30059 Krakow Poland

ISBN: (纸本)9783030180584;9783030180577

The images obtained by X-Ray or computed tomography (CT) may be contaminated with different kinds of noise or show lack of sharpness, too low or high intensity and poor contrast. Such image deficiencies can be induced by adverse physical conditions and by the transmission properties of imaging devices. A number of enhancement techniques in image processing may improve the quality of the image. These include: point arithmetic operations, smoothing and sharpening filters and histogram modifications. The choice of the technique, however, depends on the type of image deficiency. In this paper, the primary aim is to propose an efficient image enhancement method based on non-parametric estimation so as to enable medical images to have better contrast. To evaluate the method performance, X-Ray and CT images have been studied. Experimental results verify that applying this approach can engender good image enhancement performance when compared with classical techniques.

关键词： Image enhancement Contrast stretching Nonparametric estimation numerical algorithm X-ray images

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Parallelism of double Divide and Conquer algorithm for singular value decomposition

Parallelism of double Divide and Conquer algorithm for singu...

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International Conference on Parallel and Distributed Computing and Networks

作者： Konda, Taro Tsuboi, Hiroaki Takata, Masami IIwasaki, Masashi Nakamura, Yoshimasa Kyoto Univ Grad Sch Informat Dept Appl Math & Phys Sakyo Ku Yoshida Honmachi Kyoto Japan Nara Womens Univ Grad Sch Humanity & Sci Nara Japan JST SORST Osaka Japan

ISBN: (纸本)9780889866379

This paper presents some numerical evaluations of parallel double Divide and Conquer for singular value decomposition. For eigenvalue decomposition and singular value decomposition, double Divide and Conquer was recently proposed. It rst computes eigen/singular values by a compact version of Divide and Conquer. The corresponding eigen/singular vectors are then computed by twisted factorization. The speed and accuracy of double Divide and Conquer are as good or even better than standard algorithms such as QR and the original Divide and Conquer. In addition, it is expected that double Divide and Conquer has great parallelism because each step is theoretically parallel and heavy communication is not required. This paper numerically evaluates a parallel implementation of dDC with MPI on some large scale problems using a distributed memory architecture and a massively parallel super computer, especially in terms of parallelism. It shows high scalability and super linear speed-up is observed in some cases.

关键词： parallel computing singular value decomposition eigenvalue decomposition numerical algorithm linear algebra

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Mathematical Modeling and Computational Simulation of the Diffusive Behavior of Adenocarcinoma Biomarker Particles 5th

Mathematical Modeling and Computational Simulation of the Di...

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5th Workshop on Engineering Applications (WEA)

作者： Vallejo, Esteban Suarez, Gustavo Torres, William Uribe, Adolfo Univ Pontificia Bolivariana Math Grp GMAT Cir 1 70-01 Medellin 050031 Colombia Clin Las Amer Video Endoscopy Unit Dg 75B 2A-80-140 Medellin 050025 Colombia

ISBN: (纸本)9783030003500;9783030003494

Colorectal adenocarcinoma is one of the carcinogenic diseases that most affects the health of the world population. This disease is manifested biologically by the segregation of biomarker substances in the human system. This paper presents the development of a numerical-mathematical model for the study of the diffuse behavior of particles segregated by this type of cancer. Flow conditions, characteristics and properties of the diffusive medium are determined, and the study domain is defined. A mathematical description is elaborated to represent the behavior of the phenomenon by means of constitutive laws of the biosystem. A numerical-computational algorithm is constructed that makes possible the analysis of the different behavioral conditions;in this paper one of the multiples settings is showed. The computational implementation is done using Taylor series defined by finite differences with a refinement of the grid that can be controlled by the user. In addition, a structural element is incorporated with which it is intended to evaluate the level of concentration in the structure-substance contact zone. As a platform for the implementation of the algorithm, Matlab program is used. The results have been plotted by surface curves. Concentration levels are obtained at three points of interest, including concentrations at the structure-substance contact point, with concentration values of 1 * 10(-6) kg/m(3). The research is oriented in the search of an alternative that allows the detection of colorectal cancer in its early phase.

关键词： Colorectal adenocarcinoma Mathematical modeling numerical algorithm Simulation Diffusive behavior

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Methodically Unified Procedures for Outlier Detection, Clustering and Classification 4th

Methodically Unified Procedures for Outlier Detection, Clust...

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Future Technologies Conference (FTC)

作者： Kulczycki, Piotr Polish Acad Sci Ctr Informat Technol Data Anal Methods Syst Res Inst Krakow Poland AGH Univ Sci & Technol Fac Phys & Appl Comp Sci Div Informat Technol & Syst Res Krakow Poland

ISBN: (纸本)9783030325206;9783030325190

In the practice of data analysis some problems for manysided researches are caused by the methodological variety of specific algorithms, often leading to laborious interpretations and time-consuming studies. This paper presents the concept of methodically unified procedures, based on kernel estimators, for three fundamental tasks: outlier detection, clustering, and classification. Their clear interpretation facilitates the applications and potential individual modifications. The investigated procedures are distribution-free, enabling analysis and exploration of data with any distributions, also when elements are grouped in several separated parts. The results obtained depend not only on the values of particular attributes, but above all on the complex relationships between them.

关键词： Outlier detection Clustering Classification Distribution free methods Kernel estimators numerical algorithm

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On Homotopy Continuation for Speech Restoration 6th

On Homotopy Continuation for Speech Restoration

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6th International Workshop on Computational Topology in Image Context (CTIC)

作者： Onchis, Darian M. Real, Pedro Univ Vienna Fac Math Vienna Austria Univ Seville Dept Appl Math 1 Seville Spain

ISBN: (纸本)9783319394404;9783319394411

In this paper, a homotopy-based method is employed for the recovery of speech recordings from missing or corrupted samples taken in a noisy environment. The model for the acquisition device is a compressed sensing scenario using Gabor frames. To recover an approximation of the speech file, we used the basis pursuit denoising method with the homotopy continuation algorithm. We tested the proposed method with various speech recordings.

关键词： Homotopy continuation Speech restoration Basis pursuit l(1) regularization Gabor frames numerical algorithm

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Reaction Control System using Hybrid Micro-Thrusters for Guided Sounding Rocket

Reaction Control System using Hybrid Micro-Thrusters for Gui...

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6th International Conference on Recent Advances in Space Technologies (RAST)

作者： Chelaru, Teodor Viorel Chelaru, Adrian Univ POLTTEHN Bucharest Res Ctr Aeronaut & Space Ghe Polizu I Bucharest Romania INCAS Natl Inst Aerosp Res Elie Carafoli Bucharest 061126 Romania

ISBN: (纸本)9781467363969;9781467363952

The paper intend to develop a calculus model for an innovative Reaction Control System (RCS) using hybrid rocket engine technology. Our RCS uses several hybrid micro-thrusters with their thrust modulated by a separate control system. For RCS, each of the thrusters will be able to burn a few minutes and its thrust will be modulated within certain limits by controlling the oxidizer flow. In order to reduce size and weight of the RCS we will use a single oxidizer tank which will have as output a flow distributor. The basic idea is not to stop any of the engines during system's operation but to minimize their thrust reducing the oxidizer flow. This approach is avoiding the inconvenience of repeated stopping and starting of the engine, which can create reliability problems to the entire RCS. By creating thrust imbalance between various hybrid micro thrusters, one can create torques with which the attitude or the trajectory of the vehicle can be adjusted. In terms of calculation model developed, it starts from our theoretical and experimental studies, which aimed to build a computational model for hybrid rocket engine highlighting the scalability, stability and its controllability. These studies were presented in RAST 2011 and are based on our own experiments performed in Electromecanica Ploiesti. Based on this concept we achieve a calculation of the performances of the RCS and an evaluation in their size. Conclusions and any discussion will be focused on technological possibilities for achieving the system and possible areas of application for the RCS.

关键词： hybrid rocket engine nozzle orbital/suborbital vehicle numerical algorithm computation model combustion

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REMARKS ON algorithmS WITH numerical CONSTANTS

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COMMUNICATIONS OF THE ACM 1970年第9期13卷 575-&页

作者： DUNHAM, CB Univ. of Western Ont. London Canada

No abstract available.

关键词： numerical algorithm numerical constants

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A numerical-CALCULATION FOR SOME NONLINEAR OPTIMAL-CONTROL PROBLEMS WITH A TERMINAL CONSTRAINT USING SYNTHETIC RICCATI TRANSFORMATION AND ITS APPLICATIONS TO THE MANIPULATOR CONTROL PROBLEM

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ELECTRONICS AND COMMUNICATIONS IN JAPAN PART III-FUNDAMENTAL ELECTRONIC SCIENCE 1994年第5期77卷 76-86页

作者： CAI, D YAMAURA, H SHIDAMA, Y SHINSHU UNIV FAC ENGNNAGANO 380JAPAN

This paper describes a new numerical calculation algorithm for the nonlinear quadratic optimal problem with nonlinear terminal constraint. Synthetic Riccati transformation proposed earlier by the authors is utilized to solve the forementioned problem. The state differential equation is changed into two differential equations with respect to the two substates vector selected from the state vector. Then, based on the maximum principle and Kronecker's product, two differential equations with respect to the adjoint variables can be derived. To solve the forementioned differential equations, synthetic Riccati transformation is introduced to obtain a Riccati differential equation and an accessory differential equation. Thus, we can calculate the initial values of the adjoint variables by solving Riccati equations backward in time. The convergence condition about this algorithm also is provided. As the application of this algorithm, an attempt is made to apply it to an optimal trajectory control problem for a two-link manipulator. As the result of the simulation, it is confirmed that the algorithm not only has a performance of both fast convergence and high computation accuracy but also is not subject to the selection of the normal parameter for computation.

关键词： NONLINEAR CONTROL OPTIMAL CONTROL numerical algorithm algorithm CONVERGENCE MANIPULATOR CONTROL

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A numerical Analysis of the M/G/1/N Queue with Vacations

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IFAC Proceedings Volumes 2014年第2期47卷 504-509页

作者： Sofiane Ouazine Karim Abbas Department of Mathematics Exact Sciences Faculty University of Bejaia Campus of Targua Ouzemour 06000 Bejaia Algeria LAMOS Laboratory Exact Sciences Faculty University of Bejaia Campus of Targua Ouzemour 06000 Bejaia Algeria

In this paper we discuss the applicability of a computational approach based on a Taylor series expansion for the numerical evaluation of the M/G/1/N queueing model with, so called, working vacations and vacation interruptions. Specifically, we develop the performance measures of the considered system into a Taylor series with respect to the vacation parameter. Our objective is to understand how the vacation rate affects the system performance. numerical results are carried out to illustrate the efficiency of our approach.

关键词： Taylor series expansion numerical algorithm Queues Vacations Performance measures Deviation matrix

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