Edge Potential Functions (EPF) and Genetic Algorithms (GA) for Edge-Based Matching of Visual Objects

Edges are known to be a semantically rich representation of the contents of a digital image. Nevertheless, their use in practical applications is sometimes limited by computation and complexity constraints. In this paper, a new approach is presented that addresses the problem of matching visual objects in digital images by combining the concept of Edge Potential Functions (EPF) with a powerful matching tool based on Genetic Algorithms (GA). EPFs can be easily calculated starting from an edge map and provide a kind of attractive pattern for a matching contour, which is conveniently exploited by GAs. Several tests were performed in the framework of different image matching applications. The results achieved clearly outline the potential of the proposed method as compared to state of the art methodologies. (c) 2007 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works

Gradient flows of interacting Laguerre cells as discrete porous media flows

We study a class of discrete models in which a collection of particles evolves in time following the gradient flow of an energy depending on the cell areas of an associated Laguerre (i.e. a weighted Voronoi) tessellation. We consider the high number of cell limit of such systems and, using a modulated energy argument, we prove convergence towards smooth solutions of nonlinear diffusion PDEs of porous medium type

Stabilizing Consensus with Many Opinions

We consider the following distributed consensus problem: Each node in a complete communication network of size $n$ initially holds an \emph{opinion}, which is chosen arbitrarily from a finite set $\Sigma$. The system must converge toward a consensus state in which all, or almost all nodes, hold the same opinion. Moreover, this opinion should be \emph{valid}, i.e., it should be one among those initially present in the system. This condition should be met even in the presence of an adaptive, malicious adversary who can modify the opinions of a bounded number of nodes in every round. We consider the \emph{3-majority dynamics}: At every round, every node pulls the opinion from three random neighbors and sets his new opinion to the majority one (ties are broken arbitrarily). Let $k$ be the number of valid opinions. We show that, if $k \leqslant n^{\alpha}$, where $\alpha$ is a suitable positive constant, the 3-majority dynamics converges in time polynomial in $k$ and $\log n$ with high probability even in the presence of an adversary who can affect up to $o(\sqrt{n})$ nodes at each round. Previously, the convergence of the 3-majority protocol was known for $|\Sigma| = 2$ only, with an argument that is robust to adversarial errors. On the other hand, no anonymous, uniform-gossip protocol that is robust to adversarial errors was known for $|\Sigma| > 2$

Self-Stabilizing Repeated Balls-into-Bins

We study the following synchronous process that we call "repeated balls-into-bins". The process is started by assigning $n$ balls to $n$ bins in an arbitrary way. In every subsequent round, from each non-empty bin one ball is chosen according to some fixed strategy (random, FIFO, etc), and re-assigned to one of the $n$ bins uniformly at random. We define a configuration "legitimate" if its maximum load is $\mathcal{O}(\log n)$. We prove that, starting from any configuration, the process will converge to a legitimate configuration in linear time and then it will only take on legitimate configurations over a period of length bounded by any polynomial in $n$, with high probability (w.h.p.). This implies that the process is self-stabilizing and that every ball traverses all bins in $\mathcal{O}(n \log^2 n)$ rounds, w.h.p

Studio di fattibilità di una variante della SRT222 all'abitato di Greve in Chianti

Lo studio nasce dall’esigenza di risolvere la situazione di congestionamento e di disagio creata dal traffico, in particolare da quello pesante, attualmente transitante sulla SRT222, che attraversa l’intero abitato di Greve in Chianti. Lo studio della fattibilità tecnica della Variante è accompagnato da un’analisi approfondita dell’impatto dell’infrastruttura sul territorio sotto l’aspetto ambientale, economico e sociale, condotta con metodologie basate sull’integrazione delle tecniche di Analisi MultiCriteri (AMC) con i Sistemi Informativi Geografici (GIS). Il processo decisionale di valutazione, strutturato attraverso l’Analisi Gerarchica (AHP), conduce all’individuazione del corridoio infrastrutturale di minimo impatto attraverso la zonizzazione dei livelli di sensibilità del territorio, desunti dall’individuazione dei criteri e degli attributi di valutazione, spazialmente rappresentati mediante mappe geografiche georeferenziate e ricomposti in maniera pesata sulla base delle preferenze dei decisori. All’interno del corridoio viene quindi definito e geometricamente caratterizzato un tracciato ottimale con l’obiettivo, oltre che della minimizzazione dei costi di realizzazione, del rispetto delle prescrizioni normative sul dimensionamento geometrico e funzionale della strada e delle intersezioni, indicate dal DM 05/11/2001, essenziali per garantire un adeguato livello di comfort e sicurezza per gli utenti che utilizzeranno la nuova infrastruttura. Lo studio quindi, oltre a proporre una soluzione progettuale per la fattispecie di Greve, definisce e perfeziona una metodologia di supporto alle decisioni finalizzata ad integrare le modalità progettuali in ambito stradale con le crescenti esigenze di compatibilità ambientale, con benefici in termini di trasparenza, partecipazione, tempo e costi

The web will kill them all: new media, digital utopia, and political struggle in the Italian 5-Star Movement

This article examines the role of discourses about new media technology and the web in the rise of the 5-Star Movement (Movimento 5 Stelle, or M5S) in Italy. Founded by comedian and activist Beppe Grillo and web entrepreneur Gianroberto Casaleggio in 2009, this movement succeeded in becoming the second largest party at the 2013 national elections in Italy. This article aims to discuss how elements of digital utopia and web-centric discourses have been inserted into the movement’s political message, and how the construction of the web as a myth has shaped the movement’s discourse and political practice. The 5-Star Movement is compared and contrasted with other social and political movements in western countries which have displayed a similar emphasis on new media, such as the Occupy movement, the Indignados movement, and the Pirate Parties in Sweden and Germany. By adopting and mutating cyber-utopian discourses from the so-called Californian ideology, the movement symbolically identifies itself with the web. The traditional political establishment is associated with “old” media (television, radio, and the printed press), and represented as a “walking dead,” doomed to be superseded and buried by a web-based direct democracy

A mixed finite element discretization of dynamical optimal transport

In this paper we introduce a new class of finite element discretizations of the quadratic optimal transport problem based on its dynamical formulation. These generalize to the finite element setting the finite difference scheme proposed by Papadakis et al. [SIAM J Imaging Sci, 7(1):212--238,2014]. We solve the discrete problem using a proximal-splitting approach and we show how to modify this in the presence of regularization terms which are relevant for imaging applications