http://www.bibsonomy.org/burst/user/andreab/modelBibSonomy BuRST Feed for /user/andreab/model2008-07-26T22:49:51+02:00Earth Surface Processes Publicationshttp://www.bibsonomy.org/bibtex/2dfa6ab3223f72b2c1fd073e3fa999739/andreabandreab2007-10-18T11:58:42+02:00model topography mountains earth imported geophysics <span style="color:#555555;">S. D. <a href="http://www.bibsonomy.org/author/Willett">Willett</a> and R. <a href="http://www.bibsonomy.org/author/Slingerland">Slingerland</a> and N. <a href="http://www.bibsonomy.org/author/Hovius">Hovius</a> </span>(<em>2001</em>)Thu Oct 18 11:58:42 CEST 2007American Journal of Science455-485Uplift shortening and steady-state topography in active mountain belts3012001model topography mountains earth imported geophysics ABSTRACT. We present a tectonic, surface process model used to investigate the role of horizontal shortening in convergent orogens and the effects on steady-state topography. The tectonic model consists of a specified velocity field for the Earth’s surface and includes a constant uplift rate and a constant horizontal strain rate which varies to reflect the relative importance of frontal accretion and underplating in an orogenic wedge. The surface process model includes incision of a network of rivers formed by collection of applied precipitation and diffusive hillslope mass transfer. Three non-dimensional parameters describe this model: a ratio of the maximum horizontal velocity to the vertical velocity, a Peclet number expressing the efficiency of the hillslope diffusion relative to the uplift rate, and a fluvial “erosion number” reflecting the fluvial incision efficiency relative to the uplift rate. A series of models are presented demonstrating the resultant steady-state landforms parameterized by these three numbers. A finite velocity ratio results in an asymmetric form to the model mountain range, although the magnitude of the asymmetry also depends on the Peclet number. Topographic steady-state is achieved faster for models with no horizontal component to the velocity field. With finite horizontal velocity, topographic steady state is achieved only at the scale of the entire mountain range; even the first order drainage basins are unstable with time in the presence of horizontal shortening. We compare our model results to topographic profiles from active mountain ranges in Taiwan, New Zealand, and the Olympic Mountains of Washington state. All these examples exhibit asymmetric topographic form with the asymmetry consistent with the polarity of subduction, suggesting that horizontal tectonic motion is affecting the macro-geomorphic form of these ranges. SpringerLink - Journal Articlehttp://www.bibsonomy.org/bibtex/2162eb7b3982f6edd7a1322c661d7bed7/andreabandreab2007-10-13T20:31:04+02:00analysis multistates model imported time series stream mail bayesian <span style="color:#555555;">Jon <a href="http://www.bibsonomy.org/author/Kleinberg">Kleinberg</a> </span><em>Data Mining and Knowledge Discovery</em><em>7(4):373--397</em><em>#oct#2003. </em>Sat Oct 13 20:31:04 CEST 2007Data Mining and Knowledge Discovery#oct#4373--397Bursty and Hierarchical Structure in Streams72003analysis multistates model imported time series stream mail bayesian A fundamental problem in text data mining is to extract meaningful structure from document streams that arrive continuously over time. E-mail and news articles are two natural examples of such streams, each characterized by topics that appear, grow in intensity for a period of time, and then fade away. The published literature in a particular research field can be seen to exhibit similar phenomena over a much longer time scale. Underlying much of the text mining work in this area is the following intuitive premise—that the appearance of a topic in a document stream is signaled by a “burst of activity,” with certain features rising sharply in frequency as the topic emerges. ER -http://www.bibsonomy.org/bibtex/2631924a8b2f1ab8a8e2c38a43f1dbc5f/andreabandreab2007-05-25T23:45:57+02:00tagora complex zipf tagging preferential complexity co-occurence network distribution attachment model frequency <span style="color:#555555;">Harry <a href="http://www.bibsonomy.org/author/Halpin">Halpin</a> and Valentin <a href="http://www.bibsonomy.org/author/Robu">Robu</a> and Hana <a href="http://www.bibsonomy.org/author/Shepherd">Shepherd</a> </span><em>Proceedings of the 16th nternational World Wide Web Conference (WWW'07), </em><em>New York, NY, USA, </em><em>ACM Press, </em>(<em>2007</em>)Fri May 25 23:45:57 CEST 2007New York, NY, USAProceedings of the 16th nternational World Wide Web Conference (WWW'07)The Complex Dynamics of Collaborative Tagging2007tagora complex zipf tagging preferential complexity co-occurence network distribution attachment model frequency The debate within the Web community over the optimal means by which to organize information often pits formalized classications against distributed collaborative tagging systems. A number of questions remain unanswered, however, regarding the nature of collaborative tagging systems including whether coherent categorization schemes can emerge from unsupervised tagging by users. This paper uses data from the social bookmarking site del.icio.us to examine the dynamics of collaborative tagging systems. In particular, we examine whether the distribution of the frequency of use of tags for “popular” sites with a long history (many tags and many users) can be described by a power law distribution, often characteristic of what are considered complex systems. We produce a generative model of collaborative tagging in order to understand the basic dynamics behind tagging, including how a power law distribution of tags could arise. We empirically examine the tagging history of sites in order to determine how this distribution arises over time and to determine the patterns prior to a stable distribution. Lastly, by focusing on the high-frequency tags of a site where the distribution of tags is a stabilized power law, we show how tag co-occurrence networks for a sample domain of tags can be used to analyze the meaning of particular tags given their relationship to other tags.http://www.bibsonomy.org/bibtex/23916bdfa0a69023faabbd3a037c2c0e1/andreabandreab2007-05-23T20:24:56+02:00physics model fluctuation granular energy citingme minimal <span style="color:#555555;">Yair <a href="http://www.bibsonomy.org/author/Srebro">Srebro</a> and Dov <a href="http://www.bibsonomy.org/author/Levine">Levine</a> </span><em>Physical Review Letters</em><em>93(24):240601</em>(<em>2004</em>)Wed May 23 20:24:56 CEST 2007Physical Review Letters24240601Exactly Solvable Model for Driven Dissipative Systems932004physics model fluctuation granular energy citingme minimal http://www.bibsonomy.org/bibtex/2d9fd1ea1b4a9ffdaf68332409cf90b6e/andreabandreab2007-04-11T19:16:19+02:00yulesimon loreto Yule tagora model d4.1 cattuto study 2006 analytic folksonomy memory Simon servedio <span style="color:#555555;">Ciro <a href="http://www.bibsonomy.org/author/Cattuto">Cattuto</a> and Vittorio <a href="http://www.bibsonomy.org/author/Loreto">Loreto</a> and Vito D.P. <a href="http://www.bibsonomy.org/author/Servedio">Servedio</a> </span><em>Europhysics Letters</em><em>76(2):208-214</em>(<em>2006</em>)Wed Apr 11 19:16:19 CEST 2007Europhysics Letters2208-214A Yule-Simon process with memory762006yulesimon loreto Yule tagora model d4.1 cattuto study 2006 analytic folksonomy memory Simon servedio The Yule-Simon model has been used as a tool to describe the growth of diverse systems, acquiring a paradigmatic character in many fields of research. Here we study a modified Yule-Simon model that takes into account the full history of the system by means of a hyperbolic memory kernel. We show how the memory kernel changes the properties of preferential attachment and provide an approximate analytical solution for the frequency distribution density as well as for the frequency-rank distribution.http://www.bibsonomy.org/bibtex/28b100f88154692615b1e31e2e243e78c/andreabandreab2007-02-27T13:07:01+01:00model vocabulary tagora statistics tagging folksonomy flickr d4.1 <span style="color:#555555;">Cameron <a href="http://www.bibsonomy.org/author/Marlow">Marlow</a> and Mor <a href="http://www.bibsonomy.org/author/Naaman">Naaman</a> and Danah <a href="http://www.bibsonomy.org/author/Boyd">Boyd</a> and Marc <a href="http://www.bibsonomy.org/author/Davis">Davis</a> </span><em>Collaborative Web Tagging Workshop at WWW2006, </em><em>May2006. </em>Tue Feb 27 13:07:01 CET 2007Collaborative Web Tagging Workshop at WWW2006May{Position Paper, Tagging, Taxonomy, Flickr, Article, ToRead}2006model vocabulary tagora statistics tagging folksonomy flickr d4.1 In recent years, tagging systems have become increasingly popular. These systems enable users to add keywords (i.e., “tags”) to Internet resources (e.g., web pages, images, videos) without relying on a controlled vocabulary. Tagging systems have the potential to improve search, spam detection, reputation systems, and personal organization while introducing new modalities of social communication and opportunities for data mining. This potential is largely due to the social structure that underlies many of the current systems. Despite the rapid expansion of applications that support tagging of resources, tagging systems are still not well studied or understood. In this paper, we provide a short description of the academic related work to date. We offer a model of tagging systems, specifically in the context of web-based systems, to help us illustrate the possible benefits of these tools. Since many such systems already exist, we provide a taxonomy of tagging systems to help inform their analysis and design, and thus enable researchers to frame and compare evidence for the sustainability of such systems. We also provide a simple taxonomy of incentives and contribution models to inform potential evaluative frameworks. While this work does not present comprehensive empirical results, we present a preliminary study of the photosharing and tagging system Flickr to demonstrate our model and explore some of the issues in one sample system. This analysis helps us outline and motivate possible future directions of research in tagging systems.http://www.bibsonomy.org/bibtex/255983b1b3af5ddb694c176e3af0e644f/andreabandreab2006-12-21T18:33:55+01:00model statistical network river theory rivernetworks erosion physics <span style="color:#555555;">Jayanth R. <a href="http://www.bibsonomy.org/author/Banavar">Banavar</a> and Francesca <a href="http://www.bibsonomy.org/author/Colaiori">Colaiori</a> and Allesandro <a href="http://www.bibsonomy.org/author/Flammini">Flammini</a> and Achille <a href="http://www.bibsonomy.org/author/Giacometti">Giacometti</a> and Amos <a href="http://www.bibsonomy.org/author/Maritan">Maritan</a> and Andrea <a href="http://www.bibsonomy.org/author/Rinaldo">Rinaldo</a> </span><em>Physical Review Letters</em><em>78(23):4522-4525</em>(<em>1997</em>)Thu Dec 21 18:33:55 CET 2006Physical Review Letters234522-4525Sculpting of a Fractal River Basin781997model statistical network river theory rivernetworks erosion physics The principle of reparametrization invariance is used to derive a dynamical equation for the erosion of the landscape of the drainage basin of river networks. The stationary solutions of the equation are found to have scaling behavior that is consistent with observational data. Our analytic prediction of the main stream profile is confirmed by numerical results and is amenable to direct observational verification.[cond-mat/0602611] k-core (bootstrap) percolation on complex networks: Critical phenomena and nonlocal effectshttp://www.bibsonomy.org/bibtex/251186ba16a6e366133245628b780071c/andreabandreab2006-12-18T20:20:02+01:00simulation network imported model percolation kcore networks models physics graphs theory <span style="color:#555555;">A. V. <a href="http://www.bibsonomy.org/author/Goltsev">Goltsev</a> and S. N. <a href="http://www.bibsonomy.org/author/Dorogovtsev">Dorogovtsev</a> and J. F. F. <a href="http://www.bibsonomy.org/author/Mendes">Mendes</a> </span><em>Physical Review E</em>(<em>2006</em>)Mon Dec 18 20:20:02 CET 2006Physical Review E056101k-core (bootstrap) percolation on complex networks: Critical phenomena and nonlocal effects732006simulation network imported model percolation kcore networks models physics graphs theory We develop the theory of the k-core (bootstrap) percolation on uncorrelated random networks with arbitrary degree distributions. We show that the k-core percolation is an unusual, hybrid phase transition with a jump emergence of the k-core as at a first order phase transition but also with a critical singularity as at a continuous transition. We describe the properties of the k-core, explain the meaning of the order parameter for the k-core percolation, and reveal the origin of the specific critical phenomena. We demonstrate that a so-called ``corona'' of the k-core plays a crucial role (corona is a subset of vertices in the k-core which have exactly k neighbors in the k-core). It turns out that the k-core percolation threshold is at the same time the percolation threshold of finite corona clusters. The mean separation of vertices in corona clusters plays the role of the correlation length and diverges at the critical point. We show that a random removal of even one vertex from the k-core may result in the collapse of a vast region of the k-core around the removed vertex. The mean size of this region diverges at the critical point. We find an exact mapping of the k-core percolation to a model of cooperative relaxation. This model undergoes critical relaxation with a divergent rate at some critical moment.[cond-mat/0609341] The dynamical collision network in granular gaseshttp://www.bibsonomy.org/bibtex/24d8844a74d4a378c21ae7fdf939d2ed3/andreabandreab2006-12-18T20:10:08+01:00statistics granular models network simulation physics kcore imported model <span style="color:#555555;">Jose Ignacio <a href="http://www.bibsonomy.org/author/Alvarez-Hamelin">Alvarez-Hamelin</a> and Andrea <a href="http://www.bibsonomy.org/author/Puglisi">Puglisi</a> </span>(<em>2006</em>)Mon Dec 18 20:10:08 CET 2006The dynamical collision network in granular gases2006statistics granular models network simulation physics kcore imported model We dynamically construct the interaction network in a granular gas, using the sequence of collisions collected in an MD event driven simulation of inelastic hard disks from time 0 till time t. The network is decomposed into its k-core structure: particles in a core of index k have collided at least k times with other particles in the same core. The difference between cores k+1 and k is the so-called k-shell, and the set of all shells is a complete and on-overlapping decomposition of the system. Because of energy dissipation, the gas cools down: its initial spatially homogeneous dynamics, characterized by the Haff law, i.e. a t^{-2} energy decay, is unstable towards a strongly inhomogeneous phase with clusters and vortices, where energy decays as t^{-1}. The clear transition between those two phases appears in the evolution of the k-shells structure in the collision network. In the homogeneous regime the k-shell structure evolves as in a growing network with fixed number of vertices and randomly added links: the shell distribution is strongly peaked around the most populated shell, which has an index k\_{max} ~ 0.9 <d> with <d> the average number of collisions experienced by a particle. During the final non-homogeneous regime a growing fraction of collisions is concentrated in small, almost closed, 'communities' of particles: k\_{max} is no more linear in <d> and the distribution of shells becomes extremely large developing a power-law tail ~ k^{-3} for high shell indexes. We propose the k-shell decomposition as a quantitative characterization of Molecular Chaos violation.http://www.bibsonomy.org/bibtex/236d933318b0e03fab1987ea7d9639b38/andreabandreab2006-12-05T17:34:04+01:00model tagora yule review d4.1 power models simon paper submission article zipf law <span style="color:#555555;">Michael <a href="http://www.bibsonomy.org/author/Mitzenmacher">Mitzenmacher</a> </span><em>submitted to Internet Mathematics</em>(<em>2004</em>)Tue Dec 05 17:34:04 CET 2006submitted to Internet Mathematics A Brief History of Generative Models for Power Law and Lognormal Distributions - submission version 2004model tagora yule review d4.1 power models simon paper submission article zipf law Recently, I became interested in a current debate over whether file size distributions are best modelled by a power law distribution or a lognormal distribution. In trying to learn enough about these distributions to settle the question, I found a rich and long history, spanning many fields. Indeed, several recently proposed models from the computer science community have antecedents in work from decades ago. Here, I briefly survey some of this history, focusing on underlying generative models that lead to these distributions. One finding is that lognormal and power law distributions connect quite naturally, and hence, it is not surprising that lognormal distributions have arisen as a possible alternative to power law distributions across many fields. http://www.bibsonomy.org/bibtex/27cef5c65c8874e9d263a188b08993dfb/andreabandreab2006-12-05T17:30:15+01:00power article simon paper law d4.1 tagora zipf models review model yule <span style="color:#555555;">Michael <a href="http://www.bibsonomy.org/author/Mitzenmacher">Mitzenmacher</a> </span><em>Internet Mathematics</em><em>1(2):226-251</em>(<em>2004</em>)Tue Dec 05 17:30:15 CET 2006Internet Mathematics 2 226-251A Brief History of Generative Models for Power Law and Lognormal Distributions1 2004power article simon paper law d4.1 tagora zipf models review model yule Original Yule paperhttp://www.bibsonomy.org/bibtex/2f271b1f55e014f7d4f2c8525a0f11d29/andreabandreab2006-12-05T17:21:21+01:00evolution d4.1 yule theory zipf model <span style="color:#555555;">G. <a href="http://www.bibsonomy.org/author/Udny Yule">Udny Yule</a> </span><em>Royal Society of London Philosophical Transactions Series B</em>(<em>1925</em>)Tue Dec 05 17:21:21 CET 2006Royal Society of London Philosophical Transactions Series B21--87A Mathematical Theory of Evolution, Based on the Conclusions of Dr. J. C. Willis, F.R.S.2131925evolution d4.1 yule theory zipf model http://www.bibsonomy.org/bibtex/24b420549ea2f612a7ca28d81327dcec7/andreabandreab2006-12-05T12:13:07+01:00simon tex zipf tagora model statistics linguistics d4.1 <span style="color:#555555;">P. <a href="http://www.bibsonomy.org/author/Lansky">Lansky</a> and T. <a href="http://www.bibsonomy.org/author/Radil-Weiss">Radil-Weiss</a> </span><em>Journal Journal of mathematical psychology</em><em>21(1):53-65</em>(<em>1980</em>)Tue Dec 05 12:13:07 CET 2006Journal Journal of mathematical psychology153-65A Generalization of the Yule-Simon Model, with Special Reference to Word-Association Tests and Neural Cell Assembly Formation.211980simon tex zipf tagora model statistics linguistics d4.1 DBLP Record 'conf/acl/Baayen91'http://www.bibsonomy.org/bibtex/25130f4955af49c18e6339ae833dfe006/andreabandreab2006-12-04T17:08:06+01:00imported simon statistics d4.1 distribution language tagora model words mandelbrot zipf stochastic models frequency linguistics <span style="color:#555555;">R. <a href="http://www.bibsonomy.org/author/Harald Baayen">Harald Baayen</a> </span><em>ACL, </em><em>page271-278. </em>(<em>1991</em>)Mon Dec 04 17:08:06 CET 2006ACL271-278A Stochastic Process for Word Frequency Distributions.1991imported simon statistics d4.1 distribution language tagora model words mandelbrot zipf stochastic models frequency linguistics http://www.bibsonomy.org/bibtex/211ff73ed92f9fcbd9f997ed83f7d17e9/andreabandreab2006-12-01T16:29:10+01:00theory physics urn d4.1 tagora preferetial model network models attachment <span style="color:#555555;">M.V. <a href="http://www.bibsonomy.org/author/Simkin">Simkin</a> and V.P. <a href="http://www.bibsonomy.org/author/Roychowdhury">Roychowdhury</a> </span>(<em>2006</em>)Fri Dec 01 16:29:10 CET 2006Re-inventing Willis2006theory physics urn d4.1 tagora preferetial model network models attachment Scientists often re-invent things which were long known. Here we review these activities as related to the mechanism of producing power law distributions, originally proposed in 1922 by Yule to explain experimental data on the sizes of biological genera, collected by Willis. We estimate that scientists are busy re-discovering America about 2/3 of time.QUALCOSAhttp://www.bibsonomy.org/bibtex/2d745ef299afb2901be71685a08dbcacc/andreabandreab2006-11-10T15:23:17+01:00physics model statistical urns polya soc <span style="color:#555555;">M. <a href="http://www.bibsonomy.org/author/Marsili">Marsili</a> and A. <a href="http://www.bibsonomy.org/author/Valleriani">Valleriani</a> </span><em>Eur. Phys. J. B</em>(<em>1998</em>)Fri Nov 10 15:23:17 CET 2006Eur. Phys. J. B417-420Self organization of interacting polya urns31998physics model statistical urns polya soc We introduce a simple model which shows non-trivial self organized critical properties. The model describes a system of interacting units, modelled by Polya urns, subject to perturbations and which occasionally break down. Three equivalent formulations - stochastic, quenched and deterministic - are shown to reproduce the same dynamics. Among the novel features of the model are a non-homogeneous stationary state, the presence of a non-stationary critical phase and non-trivial exponents even in mean field. We discuss simple interpretations in term of biological evolution and earthquake dynamics and we report on extensive numerical simulations in dimensions d=1,2 as well as in the random neighbors limit.http://www.bibsonomy.org/bibtex/25dee47ed88d3095cd8850b80186811e2/andreabandreab2006-10-17T20:17:55+02:00model percolation myown etching coastline physics erosion prl 2004 stochastic coastal cnrbest5 <span style="color:#555555;">B. <a href="http://www.bibsonomy.org/author/Sapoval">Sapoval</a> and A. <a href="http://www.bibsonomy.org/author/Baldassarri">Baldassarri</a> and A. <a href="http://www.bibsonomy.org/author/Gabrielli">Gabrielli</a> </span><em>Physical Review Letters</em><em>93(9):098501</em>(<em>2004</em>)Tue Oct 17 20:17:55 CEST 2006Physical Review Letters9098501Self-Stabilized Fractality of Seacoasts through Damped Erosion932004model percolation myown etching coastline physics erosion prl 2004 stochastic coastal cnrbest5 Erosion of rocky coasts spontaneously creates irregular seashores. But the geometrical irregularity, in turn, damps the sea waves, decreasing the average wave amplitude. There may then exist a mutual self-stabilization of the wave amplitude together with the irregular morphology of the coast. A simple model of such stabilization is studied. It leads, through a complex dynamics of the earth-sea interface, to the appearance of a stationary fractal seacoast with a dimension close to 4=3. Fractal geometry here plays the role of a morphological attractor directly related to percolation geometry. http://www.bibsonomy.org/bibtex/2dbedac03f6c8c1ffffad95f847d72103/andreabandreab2006-10-17T19:23:12+02:00lattice myown coarsening vortices pre 2002 granular gases xy model <span style="color:#555555;">A. <a href="http://www.bibsonomy.org/author/Baldassarri">Baldassarri</a> and U. <a href="http://www.bibsonomy.org/author/Marini Bettolo Marconi">Marini Bettolo Marconi</a> and A. <a href="http://www.bibsonomy.org/author/Puglisi">Puglisi</a> </span><em>Physical Review E (Statistical, Nonlinear, and Soft Matter Physics)</em><em>65(5):051301</em>(<em>2002</em>)Tue Oct 17 19:23:12 CEST 2006Physical Review E (Statistical, Nonlinear, and Soft Matter Physics)5051301Cooling of a lattice granular fluid as an ordering process652002lattice myown coarsening vortices pre 2002 granular gases xy model We present a microscopic model of granular medium to study the role of dynamical correlations and the onset of spatial order induced by the inelasticity of the interactions on the velocity field. In spite of its simplicity and intrinsic limitations, it features several aspects of the rich phenomenology observed in granular materials and allows to make contact with other topics of statistical mechanics such as diffusion processes, domain growth, aging phenomena. Interestingly, while local observables, being controlled by the largest wavelength fluctuations, seem to suggest a purely diffusive behavior, the formation of spatially extended structures and topological defects, such as vortices and shocks, reveals a more complex scenario. Finally, only for quasielastic systems, we observe a neat scale separation, which represents a fundamental hypothesis to develop a granular hydrodynamics.http://www.bibsonomy.org/bibtex/21950c2468045bd7036f3171ea2a42525/andreabandreab2006-10-17T19:22:29+02:00etching percolation 2000 pre myown model simulations <span style="color:#555555;">A. <a href="http://www.bibsonomy.org/author/Gabrielli">Gabrielli</a> and A. <a href="http://www.bibsonomy.org/author/Baldassarri">Baldassarri</a> and B. <a href="http://www.bibsonomy.org/author/Sapoval">Sapoval</a> </span><em>Physical Review E (Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics)</em><em>62(3):3103-3115</em>(<em>2000</em>)Tue Oct 17 19:22:29 CEST 2006Physical Review E (Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics)33103-3115Surface hardening and self-organized fractality through etching of random solids622000etching percolation 2000 pre myown model simulations When a finite volume of etching solution is in contact with a disordered solid, complex dynamics of the solid-solution interface develop. If the etchant is consumed in the chemical reaction, the dynamics stop spontaneously on a self-similar fractal surface. As only the weakest sites are corroded, the solid surface gets progressively harder and harder. At the same time, it becomes rougher and rougher uncovering the critical spatial correlations typical of percolation. From this, the chemical process reveals the latent percolation criticality hidden in any random system. Recently, a simple minimal model was introduced by Sapoval et al. to describe this phenomenon. Through analytic and numerical study, we obtain a detailed description of the process. The time evolution of the solution corroding power and of the distribution of resistance of surface sites is studied in detail. This study explains the progressive hardening of the solid surface. Finally, this dynamical model appears to belong to the universality class of gradient percolation.http://www.bibsonomy.org/bibtex/2f0e5fd0f0eba8d57eb8d2f0089ef7b9e/andreabandreab2006-10-17T19:20:31+02:00model friction granular experiments myown fluctuations statistics prl stick-slip cnrbest5 2006 <span style="color:#555555;">A. <a href="http://www.bibsonomy.org/author/Baldassarri">Baldassarri</a> and F. <a href="http://www.bibsonomy.org/author/Dalton">Dalton</a> and A. <a href="http://www.bibsonomy.org/author/Petri">Petri</a> and S. <a href="http://www.bibsonomy.org/author/Zapperi">Zapperi</a> and G. <a href="http://www.bibsonomy.org/author/Pontuale">Pontuale</a> and L. <a href="http://www.bibsonomy.org/author/Pietronero">Pietronero</a> </span><em>Physical Review Letters</em><em>96(11):118002</em>(<em>2006</em>)Tue Oct 17 19:20:31 CEST 2006Physical Review Letters11118002Brownian Forces in Sheared Granular Matter962006model friction granular experiments myown fluctuations statistics prl stick-slip cnrbest5 2006 We present results from a series of experiments on a granular medium sheared in a Couette geometry and show that their statistical properties can be computed in a quantitative way from the assumption that the resultant from the set of forces acting in the system performs a Brownian motion. The same assumption has been utilized, with success, to describe other phenomena, such as the Barkhausen effect in ferromagnets, and so the scheme suggests itself as a more general description of a wider class of driven instabilities.