arXiv subjects

Alessandra Papini

Publications and source records attributed to Alessandra Papini.

4 recordsLinked to original sources

arXiv2026

Heat and mass transfer through fabric: a model for fabric drying with heated cylinders

Textile drying is a key operation in the textile production cycle as it represents one of the most energy-intensive stages and plays a critical role in determining both product quality and overall process efficiency. In this work we propose a mathematical model for the drying process of a generic textile material using heated cylinders, operating under low-pressure conditions. The model's parameters are estimated by nonlinear least squares regression. Given a specific fabric, the developed model allows to predict the drying time and the residual moisture content. The model is validated using real world data provided by a major Italian textile company.

math.NA↗

arXiv2023

ATE-SG: Alternate Through the Epochs Stochastic Gradient for Multi-Task Neural Networks

This paper introduces novel alternate training procedures for hard-parameter sharing Multi-Task Neural Networks (MTNNs). Traditional MTNN training faces challenges in managing conflicting loss gradients, often yielding sub-optimal performance. The proposed alternate training method updates shared and task-specific weights alternately through the epochs, exploiting the multi-head architecture of the model. This approach reduces computational costs per epoch and memory requirements. Convergence properties similar to those of the classical stochastic gradient method are established. Empirical experiments demonstrate enhanced training regularization and reduced computational demands. In summary, our alternate training procedures offer a promising advancement for the training of hard-parameter sharing MTNNs.

cs.LG↗

arXiv2021

Takagi factorization of matrices depending on parameters and locating degeneracies of singular values

In this work we consider the Takagi factorization of a matrix valued function depending on parameters. We give smoothness and genericity results and pay particular attention to the concerns caused by having either a singular value equal to $0$ or multiple singular values. For these phenomena, we give theoretical results showing that their co-dimension is $2$, and we further develop and test numerical methods to locate in parameter space values where these occurrences take place. Numerical study of the density of these occurrences is performed.

math.NA↗

arXiv2021

Decompositions and coalescing eigenvalues of symmetric definite pencils depending on parameters

In this work, we consider symmetric positive definite pencils depending on two parameters. That is, we are concerned with the generalized eigenvalue problem $A(x)-\lambda B(x)$, where $A$ and $B$ are symmetric matrix valued functions in ${\mathbb R}^{n\times n}$, smoothly depending on parameters $x\in \Omega\subset {\mathbb R}^2$; further, $B$ is also positive definite. In general, the eigenvalues of this multiparameter problem will not be smooth, the lack of smoothness resulting from eigenvalues being equal at some parameter values (conical intersections). We first give general theoretical results on the smoothness of eigenvalues and eigenvectors for the present generalized eigenvalue problem, and hence for the corresponding projections, and then perform a numerical study of the statistical properties of coalescing eigenvalues for pencils where $A$ and $B$ are either full or banded, for several bandwidths. Our numerical study will be performed with respect to a random matrix ensemble which respects the underlying engineering problems motivating our study.

math.NA↗