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

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

n/

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

Machine learning use for prognostic purposes in multiple sclerosis

The course of multiple sclerosis begins with a relapsing-remitting phase, which evolves into a secondarily progressive form over an extremely variable period, depending on many factors, each with a subtle influence. To date, no prognostic factors or risk score have been validated to predict disease course in single individuals. This is increasingly frustrating, since several treatments can prevent relapses and slow progression, even for a long time, although the possible adverse effects are relevant, in particular for the more effective drugs. An early prediction of disease course would allow differentiation of the treatment based on the expected aggressiveness of the disease, reserving high-impact therapies for patients at greater risk. To increase prognostic capacity, approaches based on machine learning (ML) algorithms are being attempted, given the failure of other approaches. Here we review recent studies that have used clinical data, alone or with other types of data, to derive prognostic models. Several algorithms that have been used and compared are described. Although no study has proposed a clinically usable model, knowledge is building up and in the future strong tools are likely to emerge

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

nzeb target for existing buildings case study of historical educational building in mediterranean climate

Abstract A key element of the Energy Performance of Building Directive 2010/31/EU is the introduction of nearly zero energy building (NZEB) standard for new constructions. However, considering the very low rate of new built volume, the major change for achieve the sustainable grow of the European economy, appears to be the renovation of existing building stock. But, is it possible to reach very low or nearly zero energy standard during refurbishment design? Proposed paper tries to answer this question, evaluating if the refurbishment of historic architectures to very low energy need is possible and economically feasible. With reference to a case study, this paper investigates the cost-optimal energy refurbishment of a Renaissance-style palace, located in the center of Naples, South Italy. The adopted methodology consists of various steps. Firstly, a model of the building has been accurately built and calibrated. Then, it has been used to evaluate possible interventions concerning both the envelope and the energy systems. The best solutions, chosen according to the European methodology of cost-optimality, have been combined in a last simulation. The results show that great energy savings as well as economic and environmental improvements are possible, although heritage buildings present a less flexibility in the proposal of energy efficiency measures