Search

Your search keyword '"Trevisan, Francesco"' showing total 111 results
Start Over Author "Trevisan, Francesco" Publication Year Range Last 10 years
111 results on '"Trevisan, Francesco"'

1. The curved Mimetic Finite Difference method: allowing grids with curved faces

Author

Pitassi, Silvano, Ghiloni, Riccardo, Petretti, Igor, Trevisan, Francesco, and Specogna, Ruben

Subjects
Mathematics - Numerical Analysis
Abstract

We present a new mimetic finite difference method for diffusion problems that converges on grids with \textit{curved} (i.e., non-planar) faces. Crucially, it gives a symmetric discrete problem that uses only one discrete unknown per curved face. The principle at the core of our construction is to abandon the standard definition of local consistency of mimetic finite difference methods. Instead, we exploit the novel and global concept of $P_{0}$-consistency. Numerical examples confirm the consistency and the optimal convergence rate of the proposed mimetic method for cubic grids with randomly perturbed nodes as well as grids with curved boundaries., Comment: Accepted manuscript

Published
2022
Full Text
View/download PDF

2. Explicit geometric construction of sparse inverse mass matrices for arbitrary tetrahedral grids

Author

Pitassi, Silvano, Trevisan, Francesco, and Specogna, Ruben

Subjects
Mathematics - Numerical Analysis
Abstract

The geometric reinterpretation of the Finite Element Method (FEM) shows that Raviart Thomas and Nedelec mass matrices map from degrees of freedoms (DoFs) attached to geometric elements of a tetrahedral grid to DoFs attached to the barycentric dual grid. The algebraic inverses of the mass matrices map DoFs attached to the barycentric dual grid back to DoFs attached to the corresponding primal tetrahedral grid, but they are of limited practical use since they are dense. In this paper we present a new geometric construction of sparse inverse mass matrices for arbitrary tetrahedral grids and possibly anisotropic materials, debunking the conventional wisdom that the barycentric dual grid prohibits a sparse representation for inverse mass matrices. In particular, we provide a unified framework for the construction of both edge and face mass matrices and their sparse inverses. Such a unifying principle relies on novel geometric reconstruction formulas, from which, according to a well established design strategy, local mass matrices are constructed as the sum of a consistent and a stabilization term. A major difference with the approaches proposed so far is that the consistent term is defined geometrically and explicitly, that is, without the necessity of computing the inverses of local matrices. This provides a sensible speedup and an easier implementation. We use these new sparse inverse mass matrices to discretize a three dimensional Poisson problem, providing the comparison between the results obtained by various formulations on a benchmark problem with analytical solution., Comment: 6 figures, submitted on 29 July 2020

Published
2020

4. The economics of contests : theory and evidence

Author

Trevisan, Francesco, Hopkins, Ed, and Kornienko, Tatiana

Subjects
330.01, contests, competition, cost of effort, skill levels, team building optimisation, outside options
Abstract

This thesis consists of three chapters devoted to the study of the economics of contests. Each chapter can be read independently. A special attention is placed on teams’ behaviour and team-incentive schemes. These questions are particularly important as the way in which institutions reward individuals shapes the inequality of the group to which these individuals belong. Chapter 1. Optimal Prize Allocations in Group Contests. We characterize the optimal prize allocation, namely the allocation that maximizes a group’s effectiveness, in a model of contests. The model has the following features: (i) it allows for heterogeneity between and within groups; (ii) it classifies contests as “easy” and “hard” depending on whether the marginal costs are concave or convex. Thus, we show that in an “easy” contest the optimal prize allocation assigns the entire prize to one group member, the most skilled one. Conversely, all group members receive a positive share of the prize when the contest is “hard” and players have unbounded above marginal productivities. If the contest is “hard” and the marginal productivities are bounded above, then only the most skilled group members are certain of receiving a positive share of the prize for any distribution of abilities. Finally, we study the effects of a change in the distribution of abilities within a group. Our analysis shows that if the contest is either “easy” or a particular subset of “hard”, then the more the heterogeneity within a group, the higher its probability of winning the prize. Chapter 2. Inequalities within Groups: Theory and Evidence. We study the design of a team in multi-team contests. Is it better to distribute prizes among players equally, or to just one player? And is it better to spend a budget on a diverse team with stars and rookies, or on an equal team? First, we study these questions theoretically. We find that depending on the production function, it is either optimal to (i) hire superstars and rookies, and reward superstars the most, or (ii) hire a homogeneous team and reward everyone equally. Then, we test the first set of predictions in the lab. Unlike the theory, superstars or concentrated rewards alone do not help a team win. Both must be used together. Chapter 3. Model of War of Attrition with Outside Options. We study a model of war of attrition with outside options. In a society that allocates rewards via tournaments, individuals decide how much resources dedicate towards winning the prize. Conflicts are of incomplete information and agents’ type consist of their drawn valuation of the prize and valuation of the outside option. We show that this model can be reduced to a standard war of attrition with one signal. Further, we derive the symmetric perfect Bayesian equilibrium of the game and discuss possible applications.

Published
2020
Full Text
View/download PDF

7. Modeling of anechoich chambers with equivalent materials and equivalent sources

Author

Chialina, Silvano, Cicuttin, Matteo, Codecasa, Lorenzo, Solari, Giovanni, Specogna, Ruben, and Trevisan, Francesco

Subjects
Computer Science - Computational Engineering, Finance, and Science
Abstract

Numerical simulation of anechoic chambers is a hot topic since it can provide useful data about the performance of the EMC site. However, the mathematical nature of the problem, the physical dimensions of the simulated sites and the frequency ranges pose nontrivial challenges to the simulation. Computational requirements in particular will quickly become unmanageable if adequate techniques are not employed. In this work we describe a novel approach, based on equivalent elements, that enables the simulation of large chambers with modest computational resources. The method is then validated against real measurement results.

Published
2015

9. Sub-Gigahertz Path Loss Measurement Campaign in Marine Environment: A Case Study.

Author

De Piante, Marco, Midrio, Michele, Rinaldo, Roberto, Scagnetto, Ivan, Specogna, Ruben, and Trevisan, Francesco

Subjects
RADIO wave propagation, DEW point, DATA transmission systems, MARINE communication, AREA measurement
Abstract

This paper focuses on the characterization of radio propagation, and data communication in a marine environment. More specifically, we consider signal propagation when three different sub-gigahertz industrial, scientific, and medical (ISM) bands, i.e., 169 MHz, 434 MHz, and 868 MHz, are used. The main focus of the paper is to evaluate the path loss (PL), i.e., the power loss that a propagation radio wave would experience when communication occurs between a sail boat and a buoy. We describe the measurement results obtained performing three different radio power measurement campaigns, at the three different aforementioned ISM sub-gigahertz bands. We also want to correlate the radio propagation quality with the weather conditions present in the measurement areas. The obtained results show that higher distances are achieved by transmitting at lower frequencies, i.e., 169 MHz, and, on average, the propagation is directly dependent from the dew point index. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

24. Processing of hybrid laminates integrating ZrB2/SiC and SiC layers.

Author

Padovano, Elisa, Trevisan, Francesco, Biamino, Sara, and Badini, Claudio

Subjects
*LAMINATED materials, *TAPE casting, *SPECIFIC gravity, *MECHANICAL properties of condensed matter, *FLEXURAL modulus, *ADHESIVE tape, *ELASTIC modulus
Abstract

Tape casting technique was used to develop hybrid laminates constituting by SiC and ZrB2–SiC layers; the main aim is obtaining a structure which integrate the unique properties of these materials and potentially extent their application temperature range. Multilayer with ZrB2–SiC layers stacked in between SiC ones were successfully processed. Thin cracks propagated in the composite layers without affecting SiC ones; their formation was due to residual stresses developed in the two materials because of the differences in their shrinkage and coefficients of thermal expansion. However, these cracks did not significantly affect the material properties: relative density, elastic modulus and flexural strength of hybrid laminates was indeed only slightly lower than those of laminates made up of layers with the same composition. [ABSTRACT FROM AUTHOR]

Published
2020
Full Text
View/download PDF

25. Waveform engineering: State-of-the-art and future trends (invited paper)

Author

RAFFO, Antonio, VADALA', Valeria, BOSI, Gianni, TREVISAN, Francesco, Avolio, Gustavo, VANNINI, Giorgio, Raffo, A, Vadala', V, Bosi, G, Trevisan, F, Avolio, G, and Vannini, G

Subjects
Linear and nonlinear measurements, Linear and nonlinear measurement, Nonlinear modeling, Waveform engineering, Microwave transistors, Power amplifiers, Power amplifier, Computer-Aided Design, Electrical and Electronic Engineering, ING-INF/01 - ELETTRONICA, Microwave transistor, NO
Abstract

The term waveform engineering denotes all those circuit design techniques that are based on shaping the transistor voltage and current waveforms. From a general perspective, these design techniques can be grouped in two main categories according to the adopted design tool: measurement- and model-based. In the last two decades, thanks to the proliferation of setups enabling calibrated waveform acquisition at microwave frequencies, waveform engineering has attracted continuously increasing interest in the microwave engineering community. In this article, a comprehensive analysis of the waveform-engineering based design techniques is reported, paying particular attention to the advantages and drawbacks associated to each approach.

Published
2017

30. Complementary Discrete Geometric h-Field Formulation for Wave Propagation Problems

Author

Cicuttin, Matteo, Codecasa, Lorenzo, Specogna, Ruben, and Trevisan, Francesco

Subjects
Adaptive mesh refinement, Complementarity, Discrete Geometric Approach (DGA), Finite Integration Technique (FIT), Wave propagation, Electrical and Electronic Engineering, Electronic, Optical and Magnetic Materials, Electronic, Optical and Magnetic Materials
Published
2016

49. Additive manufacturing of titanium alloys in the biomedical field: processes, properties and applications.

Author

Trevisan, Francesco, Calignano, Flaviana, Aversa, Alberta, Marchese, Giulio, Lombardi, Mariangela, Biamino, Sara, Ugues, Daniele, and Manfredi, Diego

Subjects
*TITANIUM alloys, *BIOMEDICAL engineering, *MEDICAL equipment, *ELECTRON beam furnaces, *COMPUTED tomography
Abstract

The mechanical properties and biocompatibility of titanium alloy medical devices and implants produced by additive manufacturing (AM) technologies – in particular, selective laser melting (SLM), electron beam melting (EBM) and laser metal deposition (LMD) – have been investigated by several researchers demonstrating how these innovative processes are able to fulfil medical requirements for clinical applications. This work reviews the advantages given by these technologies, which include the possibility to create porous complex structures to improve osseointegration and mechanical properties (best match with the modulus of elasticity of local bone), to lower processing costs, to produce custom-made implants according to the data for the patient acquired via computed tomography and to reduce waste. [ABSTRACT FROM AUTHOR]

Published
2018
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results