413 research outputs found
Sistemi vocalici in diatopia
No full text[S. Calamai è responsabile dei §§ 2.1, 2.2, 3.4, 4.2 e delle parti introduttive
Bott–Chern cohomology and q-complete domains
No full textIn studying the Bott–Chern and Aeppli cohomologies for q-complete manifolds, we introduce the class of cohomologically Bott–Chern q-complete manifolds
An affine Birkhoff--Kellogg type result in cones with applications to functional differential equations
No full textIn this short note we prove, by means of classical fixed point index, an
affine version of a Birkhoff--Kellogg type theorem in cones. We apply our
result to discuss the solvability of a class of boundary value problems for
functional differential equations subject to functional boundary conditions. We
illustrate our theoretical results in an example.Comment: 11 page
Between linguistics and social psychology of language: the perception of non-native accents
No full textListeners can make several attitudinal judgments about a speaker based only on his/her speech. In many cases these judgments are in line with social stereotypes which are associated with the group that is represented by a certain language variety. The
matched- and verbal-guise techniques have been extensively used in the studies of language attitudes, in order to obtain reliable results on language as a marker of group identity. This paper presents a concise state-of-the art of research focusing on language attitudes, with particular attention to Italian, and provides grounds for methodological reflection through the discussion of a pilot study conducted by the author focusing on differences in how Standard Italian and three varieties of foreign accented speech (Albanian, Romanian and General American) are perceived by a sample of 97 high school students in a medium-sized city in central Italy
NONTRIVIAL SOLUTIONS OF BOUNDARY VALUE PROBLEMS FOR SECOND ORDER FUNCTIONAL DIFFERENTIAL EQUATIONS
No full textIn this paper we present a theory for the existence of multiple nontrivial solutions for a class of perturbed Hammerstein integral equations. Our methodology, rather than to work directly in cones, is to utilize the theory of fixed point index on affine cones. This approach is fairly general and covers a class of nonlocal boundary value problems for functional differential equations. Some examples are given in order to illustrate our theoretical results
La modulazione di frequenza in due varietà toscane (Pisa e Firenze). Una indagine preliminare
No full text
Experimental modal analysis of structural systems by using the fast relaxed vector fitting method
No full textSystem identification (SI) techniques can be used to identify the dynamic parameters of mechanical systems and civil infrastructures. The aim is to rapidly and consistently model the object of interest, in a quantitative and principled manner. This is also useful in establishing the capacity of a structure to serve its purpose, thus as a tool for structural health monitoring (SHM). In this context, input–output SI techniques allow precise and robust identification regardless of the actual input. However, one of the most popular and widely used approaches, the Rational Fraction Polynomial (RFP) method, has several drawbacks. The fitting problem is nonlinear and generally non-convex, with many local minima; even if linearised via weighting, it can become severely ill-conditioned. Here, a novel proposal for the broadband macro-modelling of structures in the frequency domain with several output and/or input channels is presented. A variant of the vector fitting approach, the Fast Relaxed Vector Fitting (FRVF), applied so far in the literature only for the identification of electrical circuits, is translated and adapted to serve as a technique for structural SI and compared with other traditional techniques. A study about the robustness of the FRVF method with respect to noise is carried out on a numerical system. Finally, the method is applied to two experimental case studies: a scaled model of a high-aspect-ratio (HAR) wing and the well known benchmark problem of the three-storey frame of Los Alamos laboratories. Promising results were achieved in terms of accuracy and computational performance
Nonzero Positive Solutions of Elliptic Systems with Gradient Dependence and Functional BCs
No full textWe discuss, by topological methods, the solvability of systems of second-order elliptic differential equations subject to functional boundary conditions under the presence of gradient terms in the nonlinearities. We prove the existence of nonnegative solutions and provide a non-existence result. We present some examples to illustrate the applicability of the existence and non-existence results
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