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Reconstruction of the 1783 Scilla landslide, Italy: numerical investigations on the flow-like behaviour of landslides

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LANDSLIDES 2019年第6期16卷 1065-1076页

作者： Wang, Liang Zaniboni, Filippo Tinti, Stefano Zhang, Xue Univ Bologna Dipartimento Fis & Astron DIFA Viale Berti Pichat 8 I-40127 Bologna Italy Univ Liverpool Dept Civil Engn & Ind Design Liverpool Merseyside England

This paper presents a mass flow model that includes gravity force, material stresses, drag force and topography effects solving a set of hyperbolic partial differential equations by using a so-called depth-averaged technique. The model is non-linear and general enough to tackle various problems of interest for geophysics and environmental engineering, such as the dynamic evolution of flow-like avalanches, the dam break problem (involving only water flow) and the generation of tsunami waves by landslides. The model is based on a Eulerian fluid solver, using a second-order central scheme with a minmod-like limiter;is tested against a number of typical benchmark cases, including analytical solutions and experimental laboratory data;and also compared with other numerical codes. Through this model, we study a historical tsunamigenic event occurred in 1783 in Scilla, Italy, that resulted to be catastrophic with a toll exceeding 1500 fatalities. The landslide is reconstructed by a mixture debris flow, and results are compared with the observational data and other numerical simulations.

关键词： Geophysical flow models numerical algorithm Cartesian coordinate system Flow-like landslides

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Mechanism of Solute and Thermal Characteristics in a Casson Hybrid Nanofluid Based with Ethylene Glycol Influenced by Soret and Dufour Effects

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ENERGIES 2021年第20期14卷 6818页

作者： Hafeez, Muhammad Bilal Sumelka, Wojciech Nazir, Umar Ahmad, Hijaz Askar, Sameh Gdansk Univ Technol Fac Mech Engn & Ship Technol Narutowicza 11-12 PL-80233 Gdansk Poland Poznan Univ Tech Inst Struct Anal Piotrowo 5 St PL-60965 Poznan Poland Inst Space Technol Dept Appl Math & Stat POB 2750 Islamabad 44000 Pakistan Int Telemat Univ Uninettuno Sect Math Corso Vittorio Emanuele II 39 I-00186 Rome Italy King Saud Univ Coll Sci Dept Stat & Operat Res POB 2455 Riyadh 11451 Saudi Arabia

This article models a system of partial differential equations (PDEs) for the thermal and solute characteristics under gradients (concentration and temperature) in the magnetohydrodynamic flow of Casson liquid in a Darcy porous medium. The modelled problems are highly non-linear with convective boundary conditions. These problems are solved numerically with a finite element approach under a tolerance of 10-8. A numerical algorithm (finite element approach) is provided and a numerical procedure is discussed. Convergence is also observed via 300 elements. Simulations are run to explore the dynamics of flow and the transport of heat and mass under parametric variation. To examine the impact of a temperature gradient on the transport of mass and the role of a concentration gradient on the transport of heat energy, simulations are recorded. Remarkable changes in temperature and concentration are noted when Dufour and Soret numbers are varied.

关键词： numerical algorithm heat energy mass transfer convergence finite element method

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numerical algorithms for Caputo fractional-order differential equations

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INTERNATIONAL JOURNAL OF CONTROL 2017年第6期90卷 1201-1211页

作者： Xue, Dingyu Bai, Lu Northeastern Univ Sch Informat Sci & Engn Shenyang Peoples R China Shenyang Univ Sch Informat Engn Shenyang Peoples R China

The initial value problems (IVPs) of Caputo fractional-order differential equations are very important in control systems modelling and simulation. A series of numerical algorithms are proposed in the paper in solving systematically various kinds of Caputo equations. For linear Caputo equations, the divergent problems of the existing Taylor auxiliary function are pointed out, and two effective algorithms are presented to transform the nonzero IVPs into zero ones, where the closed-form solutions are available. Furthermore, algorithms for nonlinear Caputo equation are also presented, aiming at finding numerical solutions to all kinds of Caputo equations. Error analysis for the proposed algorithms is provided, and numerical examples are presented to illustrate the accuracy and effectiveness of the algorithms.

关键词： Fractional calculus Caputo differential equation nonzero initial value problem numerical algorithm

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A new approach to thermal segregation in petroleum reservoirs: algorithm and case studies

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JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING 2021年 201卷 108367-108367页

作者： Baghooee, Hadise Montel, Francois Galliero, Guillaume Yan, Wei Shapiro, Alexander Tech Univ Denmark DTU Danish Hydrocarbon Res & Technol Ctr Lyngby Denmark Tech Univ Denmark DTU CERE Ctr Energy Resources Engn Dept Chem & Biochem Engn Lyngby Denmark Univ Pau & Pays Adour LFCR Lab Fluides Complexes & Leurs Reservoirs UMR 5150 CNRS Total UPPAE2S UPPA Pau France Tech Univ Denmark DTU CERE Ctr Energy Resources Engn Dept Chem Lyngby Denmark

In many petroleum reservoirs, the fluid properties vary through the reservoir thickness. Variation of the composition, i.e. compositional grading, can affect reserve estimation, production and enhanced oil recovery strategies. Apart from gravity, the geothermal gradient may also contribute to the fluid distribution. Thermodiffusion is the governing phenomenon determining the contribution of the geothermal gradient. The non-equilibrium thermodynamics models are applied for the calculation of the compositional gradients under the varying temperature. In order to determine the variations in pressure and composition with depth and to be able to indicate if/where a gas-oil contact exists, we have developed a model based on the principles of irreversible thermodynamics, within the approach to thermodiffusion in porous media proposed by Montel et al. (2019). Based on the relationships where pressure, chemical potentials, and thermal gradient are linked, the distribution of hydrocarbons in a petroleum reservoir is described. A computational algorithm accounting for non-ideality of the mixture, characterization, and phase transitions has been developed. The model and the computational procedure have been validated by comparison with the case studies reported in the literature for a North Sea reservoir, and with sample component distributions produced by application of molecular dynamics simulations. It has been shown that the model is capable of predicting the fluid distributions with depth with no or a minimum of adjustable parameters. The thermal gradient modifies the predicted fluid distributions making them closer to the observed data points. Depending on the mixture composition, the thermal diffusion may either enforce the effect of gravity or counteract it.

关键词： Gravity segregation Thermal gradient Thermodiffusion numerical algorithm Reservoir cases

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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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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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Computing Contraction Metrics: Comparison of Different Implementations

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IFAC-PapersOnLine 2021年第9期54卷 310-316页

作者： P. Giesl S. Hafstein I. Mehrabinezhad Department of Mathematics University of Sussex Falmer BN1 9QH United Kingdom Faculty of Physical Sciences University of Iceland Dunhagi 5 IS-107 Reykjavik Iceland

We discuss the implementation of a novel demanding algorithm to compute contraction metrics for nonlinear systems. We compare MATLAB- and C++-implementations and study the effect of parallelizing the code. Further, we explore the use of different low-level math-libraries for the C++-implementation and the use of an undocumented code-path that considerably speeds up MATLAB code on AMD’s Ryzen processors.

关键词： Contraction metric Riemannian metric Lyapunov function numerical algorithm Mesh-free collocation

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A complex fractional mathematical modeling for the love story of Layla and Majnun

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CHAOS SOLITONS & FRACTALS 2021年 150卷 111091-111091页

作者： Kumar, Pushpendra Erturk, Vedat Suat Murillo-Arcila, Marina Cent Univ Punjab Sch Basic & Appl Sci Dept Math & Stat Bathinda 151001 Punjab India Ondokuz Mayis Univ Fac Arts & Sci Dept Math TR-55200 Atakum Samsun Turkey Univ Politecn Valencia Inst Univ Matemat Pura & Aplicada Valencia 46022 Spain

In this article, we provide numerical simulations to show the importance and the effects of fractional order derivatives in psychological studies. As it is well-known, complex variables are more realistic for defining structures in different cases. In this paper, we evidence that such dynamics become more realistic when we use fractional derivatives. We study a non-integer order, non-linear mathematical model for defining a love story of Layla and Majnun (a couple in a romantic relationship). We exemplify all necessary practical calculations to study this serious psychological phenomena. The existence of the unique solution for the given model is exhibited. We use a very recent and strong modified Predictor-Corrector algorithm to evaluate the model structure. Stability of the proposed method is also given. We exemplify that the given complex fractional model is more realistic and represents reality more closely. The proposed model is very basic, significant, and efficient at introducing distinct natures by only replacing one control parameter. In this study, we found that in some of the cases there are stable limit cycles, in some cases periodic behaviours and sometimes transiently chaotic solutions exist which cannot be observed for integer order models at same parameter values. The principal contribution of this article is to exhibit the importance of non-integer order derivatives for analysing complex dynamics. The use of complex variables makes this study more effective because they have both magnitude and phase to better explore the love and can describe different emotions such as coexisting love and hate. (c) 2021 Elsevier Ltd. All rights reserved.

关键词： Psychological modelling Complex variables Fractional mathematical model numerical algorithm New generalised Caputo type fractional derivative

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Outlier Detection, Clustering, and Classification - Methodologically Unified Procedures for Conditional Approach 12th

Outlier Detection, Clustering, and Classification - Methodol...

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12th International Conference on Computational Collective Intelligence (ICCCI)

作者： Kulczycki, Piotr Franus, Krystian Polish Acad Sci Syst Res Inst Warsaw Poland AGH Univ Sci & Technol Fac Phys & Appl Comp Sci Krakow Poland

ISBN: (纸本)9783030630065;9783030630072

The subject of the study are three fundamental procedures of contemporary data analysis: outliers detection, clustering and classification. The issue is considered in a conditional approach - introduction of specific (e.g. current) values to the model allows in practice a significantly precise description of the reality under research. The same methodology has been used for all three above tasks, which considerably facilitates the interpretations, potential modifications and practical applications of the material investigated. Using non-parametric methods frees the procedures under investigation from a distribution in the considered dataset.

关键词： Data analysis Data mining Outliers detection Clustering Classification Conditional approach Distribution free methods numerical algorithm

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Memory-dependent derivative versus fractional derivative (I): Difference in temporal modeling

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JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS 2021年 384卷 112923-112923页

作者： Wang, Jin-Liang Li, Hui-Feng Qingdao Univ Technol Coll Sci Res Inst ESMD Method & Its Applicat Qingdao 266520 Shandong Peoples R China

Since the memory-dependent derivative (MDD) was developed in 2011, it has become a new branch of Fractional Calculus which is still in the ascendant nowadays. How to understand MDD and fractional derivative (FD)? What are the advantages and disadvantages for them? How do they behave in Modeling? These questions guide going deep into the illustration of memory effect. Though the FD is defined on an interval, it mainly reflects the local change. Relative to the FD, the physical meaning of MDD is much clearer. The time-delay reflects the duration of memory effect, and the kernel function reflects the dependent weight. The results show that the MDD is more suitable for temporal modeling. In addition, a numerical algorithm for MDD is also developed here. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Memory-dependent derivative (MDD) Fractional derivative (FD) Memory effect Logistic model numerical algorithm Time-delay

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