A discrepancy principle for Poisson data: uniqueness of the solution for 2D and 3D data

This paper is concerned with the uniqueness of the solution of a nonlinear equation, named discrepancy equation. For the restoration problem of data corrupted by Poisson noise, we have to minimize an objective function that combines a data-fidelity function, given by the generalized Kullback–Leibler divergence, and a regularization penalty function. Bertero et al. recently proposed to use the solution of the discrepancy equation as a convenient value for the regularization parameter. Furthermore they devised suitable conditions to assure the uniqueness of this solution for several regularization functions in 1D denoising and deblurring problems. The aim of this paper is to generalize this uniqueness result to 2D and 3D problems for several penalty functions, such as an edge preserving functional, a simple case of the class of Markov Random Field (MRF) regularization functionals and the classical Tikhonov regularization

A variable metric forward--backward method with extrapolation

Forward-backward methods are a very useful tool for the minimization of a functional given by the sum of a differentiable term and a nondifferentiable one and their investigation has experienced several efforts from many researchers in the last decade. In this paper we focus on the convex case and, inspired by recent approaches for accelerating first-order iterative schemes, we develop a scaled inertial forward-backward algorithm which is based on a metric changing at each iteration and on a suitable extrapolation step. Unlike standard forward-backward methods with extrapolation, our scheme is able to handle functions whose domain is not the entire space. Both {an ${\mathcal O}(1/k^2)$ convergence rate estimate on the objective function values and the convergence of the sequence of the iterates} are proved. Numerical experiments on several {test problems arising from image processing, compressed sensing and statistical inference} show the {effectiveness} of the proposed method in comparison to well performing {state-of-the-art} algorithms

Serafino Zappacosta: An Enlightened Mentor and Educator.

With this article, the authors aim to honor the memory of Serafino Zappacosta, who had been their mentor during the early years of their career in science. The authors discuss how the combination of Serafino Zappacosta's extraordinary commitment to teaching and passion for science created a fostering educational environment that led to the creation of the "Ruggero Ceppellini Advanced School of Immunology." The review also illustrates how the research on the MHC and the inspirational scientific context in the Zappacosta's laboratory influenced the authors' early scientific interests, and subsequent professional work as immunologists

Re-interpretation of an ancient passive cooling strategy: a new system of wooden lattice openings

Abstract Traditional passive cooling strategies are a very important tool in Mediterranean architecture to face climate changes and to limit energy consumption, both in new and ancient buildings, toward sustainability and reduction of fossil fuel consumption. Starting from the traditional architectural culture, the aim of the study is to understand how using and re-interpreting ancient constructive elements that interact with the outdoor environment, in order to assure the indoor thermal-hygrometric comfort. In this regard, the paper proposes the study of a new system of wooden lattice openings to be installed in Mediterranean buildings. It originates from the Islamic architecture and it is used especially to control natural light into the buildings. Actually, it has also the function to regulate the airflow into the indoor environment, mitigating the climate conditions and ensuring the comfort of inhabitants. For this reason, the research proposes the analysis of this system through modern computational tools and demonstrates that it can guarantee better indoor summer conditions, improving wind velocity and air change rate in the room

Hestenes method for symmetric indefinite systems in interior-point method

This paper deals with the analysis and the solution of the Karush-Kuhn-Tucker (KKT) system that arises at each iteration of an Interior-Point (IP) method for minimizing a nonlinear function subject to equality and inequality constraints.This system is generally large and sparse and it can be reduced so that the coefficient matrix is still sparse, symmetric and indefinite, with size equal to the number of the primal variables and of the equality constraints. Instead of transforming this reduced system to a quasidefinite form by regularization techniques used in available codes on IP methods, under standard assumptions on the nonlinear problem, the system can be viewed as the optimality Lagrange conditions for a linear equality constrained quadratic programming problem, so that Hestenes multipliers' method can be applied. Numerical experiments on elliptic control problems with boundary and distributed control show the effectiveness of Hestenes scheme as inner solver for IP methods

Improving the indoor climate of the traditional Ottoman houses in the Medina of Algiers

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SoK: A Unified Data Model for Smart Contract Vulnerability Taxonomies

Modern blockchains support the execution of application-level code in the form of smart contracts, allowing developers to devise complex Distributed Applications (DApps). Smart contracts are typically written in high-level languages, such as Solidity, and after deployment on the blockchain, their code is executed in a distributed way in response to transactions or calls from other smart contracts. As a common piece of software, smart contracts are susceptible to vulnerabilities, posing security threats to DApps and their users. The community has already made many different proposals involving taxonomies related to smart contract vulnerabilities. In this paper, we try to systematize such proposals, evaluating their common traits and main discrepancies. A major limitation emerging from our analysis is the lack of a proper formalization of such taxonomies, making hard their adoption within, e.g., tools and disfavoring their improvement over time as a community-driven effort. We thus introduce a novel data model that clearly defines the key entities and relationships relevant to smart contract vulnerabilities. We then show how our data model and its preliminary instantiation can effectively support several valuable use cases, such as interactive exploration of the taxonomy, integration with security frameworks for effective tool orchestration, and statistical analysis for performing longitudinal studies

Recovery of ancient bioclimatic strategies for energy retrofit in historical buildings: the case of the Infants' Tower in the Alhambra

Abstract Among Mediterranean historical buildings, the Andalusi architecture is the result of an intuitive and experimental process of adaptation to the surrounding environment. The medieval Muslims coped with difficult climatic conditions in al-Andalus through passive cooling strategies, paying attention also to the thermal comfort. The paper focuses, in particular, on natural ventilation in the Infants' Tower in the Alhambra of Granada. It has eight mashrabiyas at the top whose performance is investigated through a CFD model, in order to understand their contribution to the improvement of indoor thermal comfort and rational energy use during summer

miRNA-mRNA integrative analysis in primary myelofibrosis CD34+ cells: role of miR-155/JARID2 axis in abnormal megakaryopoiesis

Primary myelofibrosis (PMF) is a myeloproliferative neoplasm characterized by megakaryocyte (MK) hyperplasia, bone marrow fibrosis, and abnormal stem cell trafficking. PMF may be associated with somatic mutations in JAK2, MPL, or CALR. Previous studies have shown that abnormal MKs play a central role in the pathophysiology of PMF. In this work, we studied both gene and microRNA (miRNA) expression profiles in CD34(+) cells from PMF patients. We identified several biomarkers and putative molecular targets such as FGR, LCN2, and OLFM4. By means of miRNA-gene expression integrative analysis, we found different regulatory networks involved in the dysregulation of transcriptional control and chromatin remodeling. In particular, we identified a network gathering several miRNAs with oncogenic potential (eg, miR-155-5p) and targeted genes whose abnormal function has been previously associated with myeloid neoplasms, including JARID2, NR4A3, CDC42, and HMGB3. Because the validation of miRNA-target interactions unveiled JARID2/miR-155-5p as the strongest relationship in the network, we studied the function of this axis in normal and PMF CD34(+) cells. We showed that JARID2 downregulation mediated by miR-155-5p overexpression leads to increased in vitro formation of CD41(+) MK precursors. These findings suggest that overexpression of miR-155-5p and the resulting downregulation of JARID2 may contribute to MK hyperplasia in PMF