Publications related to Self-similarity

Development and clinical validation of computational imaging biomarkers for neurodegenerative diseases

Neurodegenerative and neuroinflammatory disorders often involve complex pathophysiological mechanisms that are â to this date â only partially understood. A more comprehensive understanding of those microstructural processes and their characterization ...

EPFL2024

Fractal analysis in the quantification of medical imaging associated with multiple sclerosis pathology

Maria-Alexandra Paun

Backgrounds: Multiple sclerosis (MS) is an inveterate phlogistic situation characterized by focal and vaguely diffusive de-myelination and neurodegeneration, in the sphere of central nervous system (CNS). The brain's chronic inflammatory reaction includes ...

IMR PRESS2022

Lamplighters and the bounded cohomology of Thompson's group

Nicolas Monod

We prove the vanishing of the bounded cohomology of lamplighter groups for a wide range of coefficients. This implies the same vanishing for a number of groups with self-similarity properties, such as Thompson's group F. In particular, these groups are bou ...

SPRINGER BASEL AG2022

Microscopic field theory for structure formation in systems of self-propelled particles with generic torques

Ignacio Pagonabarraga Mora, Elena Sesé Sansa

We derive a dynamical field theory for self-propelled particles subjected to generic torques and forces by explicitly coarse-graining their microscopic dynamics, described by a many-body Fokker-Planck equation. The model includes both intrinsic torques ind ...

AIP Publishing2022

Self-Structuring Of Cellular And Channel Type In Complex System Dynamics In The Framework Of Scale Relativity Theory

Maria-Alexandra Paun

In the framework of Scale Relativity Theory, by analyzing dynamics of complex system structural units based on multifractal curves, both Schrodinger and Madelung approaches are functional and complementary. The Madelung selected approach involve synchronou ...

UNIV POLITEHNICA BUCHAREST, SCI BULL2022

On the 5G Communications: Fractal-Shaped Antennas for PPDR Applications

Maria-Alexandra Paun

In this study, one method of using antennas based on fractals to cover few kinds of public protection and disaster relief (PPDR) communications was presented. Dedicated antenna forms, necessary for antenna design by 5G implementation, were enhanced to suit ...

WILEY-HINDAWI2021

Single-phase SPH modelling of plunge pool dynamic pressures at a near-prototype scale

Pedro Filipe De Almeida Manso

The turbulent plunging jet of a nearly incompressible fluid into a stagnant fluid is of great importance in many practical applications, especially for the engineering of hydropower. As an example, the dynamic load exerted by the impact of turbulent high-v ...

Taylor & Francis Ltd2021

Adhesive wear regimes on rough surfaces and interaction of micro-contacts

Jean-François Molinari, Son-Jonathan Pham-Ba

We develop an analytical model of adhesive wear between two unlubricated rough surfaces, forming micro-contacts under normal load. The model is based on an energy balance and a crack initiation criteria. We apply the model to the problem of self-affine rou ...

2021

Three-dimensional fluid-driven stable frictional ruptures

Brice Tanguy Alphonse Lecampion, Alexis Alejandro Sáez Uribe

We investigate the quasi-static growth of a fluid-driven frictional shear crack that propagates in mixed mode (II+III) on a planar fault interface that separates two identical half-spaces of a three-dimensional solid. The fault interface is characterized b ...

2022

The emergence of small-scale self-affine surface roughness from deformation

Till Junge

Most natural and man-made surfaces appear to be rough on many length scales. There is presently no unifying theory of the origin of roughness or the self-affine nature of surface topography. One likely contributor to the formation of roughness is deformati ...

AMER ASSOC ADVANCEMENT SCIENCE2020

System and method for decoding reed-muller codes

Emmanuel Abbé, Min Ye

Various embodiments are directed to Reed-Muller decoding systems and methods based on recursive projections and aggregations of cosets decoding, exploiting the self-similarity of RM codes, and extended with list-decoding procedures and with outer-code conc ...

2020

Emergence of self-affine surfaces during adhesive wear

Jean-François Molinari, Enrico Milanese, Ramin Aghababaei, Tobias Brink

Friction and wear depend critically on surface roughness and its evolution with time. An accurate control of roughness is essential to the performance and durability of virtually all engineering applications. At geological scales, roughness along tectonic ...

Nature Research2019

On the self-similarity of wind turbine wakes in a complex terrain using large eddy simulation

Arslan Salim Dar

We perform large eddy simulation of flow in a complex terrain under neutral atmospheric stratification. We study the self-similar behavior of a turbine wake as a function of varying terrain complexity and perform comparisons with a flat terrain. By plottin ...

Copernicus GmbH2019

A model for the effect of pressure gradient on turbulent axisymmetric wakes

Fernando Porté Agel, Sina Shamsoddin

Turbulent axisymmetric wakes under pressure gradient have received little attention in the literature, in spite of their fundamental and practical importance, for example, in the case of wind turbine wakes over topography. In this paper, we develop an anal ...

Cambridge University Press2018

Self-Similar Multiresonant Nanoantenna Arrays for Sensing from Near- to Mid-Infrared

Hatice Altug, Andreas Tittl, Daniel Rodrigo Lopez, Aurélian Michel John-Herpin, Odeta Limaj

Tailoring nanoscale light concentration and electromagnetic near-field enhancement over a broad spectral range is crucial for many photonics applications such as infrared spectroscopy, photodetection, and light harvesting. So far, broadband light enhanceme ...

2018

Self-Similarity of Plasmon Edge Modes on Koch Fractal Antennas

Olivier Martin, Jérémy Butet, Gabriel David Bernasconi

We investigate the plasmonic behavior of Koch snowflake fractal geometries and their possible application as broadband optical antennas. Lithographically defined planar silver Koch fractal antennas were fabricated and characterized with high spatial and sp ...

2017

Size Ratio of Fluvial Grains’ Intermediate Axes Assessed by Image Processing and Square-Hole Sieving

Severin Stähly

The comparability of grain sizes emerging from different methods are discussed, including image-based grain-size analysis. Waterworked gravel-bed surfaces from laboratory and field experiments are analyzed in detail. Grain sizes estimated using freely avai ...

American Society of Civil Engineers2017

Turbulent planar wakes under pressure gradient conditions

Fernando Porté Agel, Sina Shamsoddin

Accurate prediction of the spatial evolution of turbulent wake flows under pressure gradient conditions is required in some engineering applications such as the design of high-lift devices and wind farms over topography. In this paper, we aim to develop an ...

Cambridge University Press2017

Wavelet Statistics of Sparse and Self-Similar Images

Michaël Unser, Emrah Bostan, Julien René Pierre Fageot

It is well documented that natural images are compressible in wavelet bases and tend to exhibit fractal properties. In this paper, we investigate statistical models that mimic these behaviors. We then use our models to make predictions on the statistics of ...

Siam Publications2015

Using electrical resistance networks to enhance performance assessments of water distribution networks

Ian Smith, Gaudenz Moser, Stephanie Ann German

Pressurized fluid-distribution networks are strategic elements of civil infrastructure. In the case of fresh-water distribution networks, where leaks are common and where real performance is unknown, advanced sensor-based diagnostic methodologies have the ...

2015