1,358,676 research outputs found
René Girard
No full textSi tratta del numero monografico della rivista Studi Perugini, a. V, n. 10, curato da Ambrogio Santambrogio e Luigi Cimmino, dedicato all'opera di Reneé Girard. Contiene saggi di: R. Girard, L. Cimmino, P. Livingston, P. Dumouchel, E. Gans, R. J. Golsan, A. McKenna, S. Tomelleri, G. Fornari, W. Palaver. Con un inedito di Girard e una sua lunga intervsita fatta da M. Stella Barberi
Il marxismo analitico
No full textSi tratta del numero monografico di Studi Perugini (curato da A. Santambrogio e Luigi Cimmino) che ha lo scopo di presentare in Italia i temi e gli autori del cosiddetto marxismo analitico (saggi di: G. A. Cohen, E. O. Wright, J. E. Roemer, Ph. van Parijs, A. Carling, M. A. Lebowitz, T. Mayer, F. S. Trincia)
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Cimmino simultaneously iterative holographic projection
No full textThe Cimmino algorithm is an iterative algorithm used for solving linear equations ( Ax = b ) and is part of a wider family of algebraic reconstruction algorithms. Despite being used in computed tomography and digital signal processing, we present an approach for using it in holographic projections in the Fraunhofer region. Following the work carried out by our group on Kaczmarz holography, an earlier algebraic linear equation solver, we compare the performance and speed of Cimmino against this algorithm. Three versions of the Cimmino algorithm, Cimmino full, Cimmino eye, and Cimmino FFT, are evaluated and compared to both Kaczmarz and Gerchberg-Saxton. Interestingly, the derivation and simplification of Kaczmarz and Cimmino leads to the input-output algorithm originally derived by Fienup and while the solution is well-known, the link between these algorithms is not and despite being around since the 1930s, it was originally used to solve linear equations and not phase retrieval. While the Cimmino full and Cimmino eye reflect fairly poorly against Cimmino FFT and Kaczmarz in terms of image quality and speed, the Cimmino FFT delivers better results in terms of image quality than all algorithms considered. It is significantly faster than Kaczmarz, being only a few milliseconds slower than Gerchberg-Saxton
Proprietà pragmatiche delle dislocazioni a sinistra e delle anteposizioni in italiano. Un approccio contrastivo con l’inglese
No full textNella letteratura italiana, le dislocazioni a sinistra e le anteposizioni sono ritenute, generalmente, strutture topicalizzanti (si vedano, tra gli altri, Benincà et al. 1988, Berretta 1995, Ferrari et al. 2008; per un punto di vista differente cfr., almeno, Berruto 1985). In particolare, Benincà et al. 1988 assegnano una funzione anaforica ai casi di anteposizione dell’oggetto diretto, privi di ripresa pronominale. Nella letteratura inglese, l’ipotesi che entrambe le strutture siano topicalizzanti è accettata da alcuni (cfr. Lambrecht 1994), ma rifiutata esplicitamente da altri (cfr. Prince 1998). Inoltre, nella descrizione delle proprietà pragmatiche delle due strutture in inglese sono presi in considerazione ulteriori parametri, assenti nella descrizione dell’italiano, come la presenza di presupposizioni legate al contesto di occorrenza (Birner e Ward 1998).
A partire da un dialogo tra le due tradizioni di studio, in questo lavoro ci si pone l’obiettivo di 1) individuare le proprietà pragmatiche di dislocazioni ed anteposizioni valide a livello interlinguistico, 2) distinguere le peculiarità d’uso delle strutture in ciascuna lingua.
A tale scopo, è stato adottato un approccio contrastivo e corpus-based. Le costruzioni sintattiche indagate sono state cercate in due corpora, ciascuno di 250'000 parole, di testi giornalistici online redatti in italiano ed inglese e non tradotti. I testi sono stati raccolti nel corso del 2011 in un progetto più ampio sugli ordini marcati nell’italiano giornalistico online, a confronto con inglese, tedesco, francese e spagnolo.
Le occorrenze di dislocazione a sinistra ed anteposizione presenti nei due corpora sono state analizzate prendendo in considerazione tre parametri: (i) lo statuto informativo dell’elemento dislocato ed anteposto, seguendo la tripartizione Dato, Inferibile e Nuovo; (ii) la topicalità dell’elemento, distinguendo tra le categorie di Topic e Comment; infine, (iii) il Fuoco della struttura, unita alla valutazione della presenza/assenza di presupposizioni legate al contesto.
I risultati ottenuti costituiscono un aspetto centrale, accanto a considerazioni sulla frequenza e la forma sintattica dei costrutti, nella descrizione empirica e la distinzione teorica di dislocazioni a sinistra ed anteposizioni in italiano ed inglese (cfr. Cimmino In prep.)
Absolute configuration of fungal metabolites phyllostin and scytolide by ORD, ECD, and VCD computational analysis
No full textDue to recent advance in theoretical predictions of chiroptical properties, and the progress in computation and instrumental technology, all three methods of Optical Rotatory Dispersion (ORD), Electronic (ECD) and Vibrational Circular Dichroism (VCD) can provide nowadays very reliable approaches for assignment of the molecular absolute configuration (AC) in solution. However, in some instances, to avoid any ambiguity in configurational assignment, the use of more than one single method is justified.
In this work we present a determination of AC of two bioactive fungal metabolites, phyllostin[1] and scytolide,[2] by combined employment of theoretical/experimental analysis of their ORD, ECD, and VCD properties. We provide evidences justifying the necessity of multiple methods for safest possible AC assignment of both compounds.
References
[1] A. Evidente, A. Cimmino, A. Andolfi, M. Vurro, M.C. Zonno, A. Motta, J. Agric. Food Chem. 56 884 (2008)
[2] W.A. Ayer, Y. Fukazawa, H. Orszanska, Nat. Prod. Lett. 2 77 (1993
Partitioning strategies for the block Cimmino algorithm
No full textInternational audienceIn the context of the block Cimmino algorithm, we study preprocessing strategies to obtain block partitionings that can be applied to general linear systems of equations Ax = b. We study strategies that transform the matrix AAT into a matrix with a block tridiagonal structure. This provides a partitioning of the linear system for row projection methods because block Cimmino is essentially equivalent to block Jacobi on the normal equations and the resulting partition will yield a two- block partition of the original matrix. Therefore the resulting block partitioning should improve the rate of convergence of block row projection methods such as block Cimmino. We discuss a way of obtaining a partitioning using a dropping strategy that gives more blocks at the cost of relaxing the two-block partitioning. We then use a hypergraph partitioning that works directly on the matrix A to reduce directly the connections between blocks. We give numerical results showing the performance of these techniques both in their eéect on the convergence of the block Cimmino algorithm and in their ability to exploit parallelism
On Cimmino Integrals as residues of Zeta Functions
No full textThe following paper is a variation on a theme of
Gianfranco Cimmino on some integral representation
formulas for the solution of a linear equations system.
Cimmino was probably motivated for giving a representation
formula suitable not only for theoretical investigations
but also for applied computation.
In this paper we will prove that the Cimmino integrals
are strictly related to the residues of some zeta-like
functions associated to the linear system
Boundary Value Problems for the Cimmino System Via Quaternionic Analysis
No full textIn this paper, we study a class of boundary value problems for a first order linear partial differential equation (all of whose solutions are harmonic functions), which is called the Cimmino system. With the help of the one-to-one correspondence between the theory of quaternion valued hyperholomorphic functions and that of Cimmino system's solutions, necessary and sufficient conditions for the solvability of the non-homogeneous Cimmino system coupled by the boundary conditions are derived and its general solution is explicitly described. (C) 2012 Elsevier Inc. All rights reserved
Introduction to Vico’s Oration on the Death of Donn’Angela Cimmino
No full textWhen Angela Cimmino died, Vico wrote a funeral oration on her virtues. The essay makes a rhetorical analysis of it, showing the classical and christian intertextuality, style, and the agiographic and pedagogic aspects that come from the description of Angela Cimmino's death
A NOVEL PARTITIONING METHOD FOR ACCELERATING THE BLOCK CIMMINO ALGORITHM
No full textWe propose a novel block-row partitioning method in order to improve the convergence rate of the block Cimmino algorithm for solving general sparse linear systems of equations. The convergence rate of the block Cimmino algorithm depends on the orthogonality among the block rows obtained by the partitioning method. The proposed method takes numerical orthogonality among block rows into account by proposing a row inner-product graph model of the coefficient matrix. In the graph partitioning formulation defined on this graph model, the partitioning objective of minimizing the cutsize directly corresponds to minimizing the sum of interblock inner products between block rows thus leading to an improvement in the eigenvalue spectrum of the iteration matrix. This in turn leads to a significant reduction in the number of iterations required for convergence. Extensive experiments conducted on a large set of matrices confirm the validity of the proposed method against a state-of-the-art method
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