Search results for " Regular"
showing 10 items of 197 documents
MR3714763 Reviewed Bargetz, C.(A-INSB); Nigsch, E. A.(A-WIEN-WPI); Ortner, N.(A-INSB) Convolvability and regularization of distributions. (English su…
2018
Referring to the theory of vector-valued distributions due to L. Schwartz, the authors, starting from a formulation due to Hirata and Shiraishi, carry out a study about generalizations of the convolvability and regularization of distributions, without test functions but by means of kernels. Further topological features, such as boundedness and relative compactness of subsets of distributions, are exhibited in light of previous results.
Fast nonstationary preconditioned iterative methods for ill-posed problems, with application to image deblurring
2013
We introduce a new iterative scheme for solving linear ill-posed problems, similar to nonstationary iterated Tikhonov regularization, but with an approximation of the underlying operator to be used for the Tikhonov equations. For image deblurring problems, such an approximation can be a discrete deconvolution that operates entirely in the Fourier domain. We provide a theoretical analysis of the new scheme, using regularization parameters that are chosen by a certain adaptive strategy. The numerical performance of this method turns out to be superior to state-of-the-art iterative methods, including the conjugate gradient iteration for the normal equation, with and without additional precondi…
On the discrete linear ill‐posed problems
1999
An inverse problem of photo‐acoustic spectroscopy of semiconductors is investigated. The main problem is formulated as the integral equation of the first kind. Two different regularization methods are applied, the algorithms for defining regularization parameters are given. Diskrečiųjų blogai sąlygotų uždavinių klausimu Santrauka Darbe nagrinejamas foto‐akustines spektroskopijos puslaidininkiuose uždavinys, kuriame i vertinami nešeju difuzijos ir rekombinacijos procesai. Reikia atstatyti šaltinio funkcija f(x), jei žinoma antrosios eiles difuzijos lygtis ir atitinkamos kraštines salygos. Naudojantis matavimu, atliktu ivairiuose dažniuose, rezultatais sprendžiamas atvirkštinis uždavinys, kel…
Multicomponent line profile restoring by means of ill-posed inverse task solution
2017
The investigation of the criteria of usage of the Tikhonov regularization method for multicomponent overlapping line profiles restoring was done by means of model task solution. The influence of the width and kind of the instrumental function, number of the components of the profile and distance between components are discussed.
IL PIRO PIRO BOSCHERECCIO TRINGA GLAREOLA IN ITALIA È UNO SVERNANTE REGOLARE
2019
The Wood Sandpiper,Tringa glareola, is a regular wintering species in Italy. We revised wintering status of Wood Sandpiper analysing 75 sightings (99 individuals) from December 2001 until January 2019. Data were collected from direct monitoring in Latium and Sicily and integrated by bibliography and national/regional data base. The species is regularly wintering with an estimate population of 1-9 individuals per year (mean value 1.32 individuals/sighting; DS=0.71). Tringa glareola was recorded in 40 sites, 20 Provinces and 10 Regions. Preferred wintering places are in Latium, Sicily and Sardinia. Utilised sites during last wintering seasons are increasing.
Characterization of the Clarke regularity of subanalytic sets
2017
International audience; In this note, we will show that for a closed subanalytic subset $A \subset \mathbb{R}^n$, the Clarke tangential regularity of $A$ at $x_0 \in A$ is equivalent to the coincidence of the Clarke's tangent cone to $A$ at $x_0$ with the set \\$$\mathcal{L}(A, x_0):= \bigg\{\dot{c}_+(0) \in \mathbb{R}^n: \, c:[0,1]\longrightarrow A\;\;\mbox{\it is Lipschitz}, \, c(0)=x_0\bigg\}.$$Where $\dot{c}_+(0)$ denotes the right-strict derivative of $c$ at $0$. The results obtained are used to show that the Clarke regularity of the epigraph of a function may be characterized by a new formula of the Clarke subdifferential of that function.
Differential inclusions involving normal cones of nonregular sets in Hilbert spaces
2017
This thesis is dedicated to the study of differential inclusions involving normal cones of nonregular sets in Hilbert spaces. In particular, we are interested in the sweeping process and its variants. The sweeping process is a constrained differential inclusion involving normal cones which appears naturally in several applications such as elastoplasticity, electrical circuits, hysteresis, crowd motion, etc.This work is divided conceptually in three parts: Study of positively alpha-far sets, existence results for differential inclusions involving normal cones and characterizations of Lyapunov pairs for the sweeping process. In the first part (Chapter 2), we investigate the class of positivel…
Evaluation of the areal material distribution of paper from its optical transmission image
2011
International audience; The goal of this study was to evaluate the areal mass distribution (defined as the X-ray transmission image) of paper from its optical transmission image. A Bayesian inversion framework was used in the related deconvolution process so as to combine indirect optical information with a priori knowledge about the type of paper imaged. The a priori knowledge was expressed in the form of an empirical Besov space prior distribution constructed in a computationally effective way using the wavelet transform. The estimation process took the form of a large-scale optimization problem, which was in turn solved using the gradient descent method of Barzilai and Borwein. It was de…
Apprentissage implicite de régularités : Mise en évidence d'une différence d'apprentissage entre tâches motrices continues et discrètes
2005
This research is concerned with the implicit learning of regularities in continuous motor tasks (e.g., tracking tasks) and discrete tasks (e.g., Serial Reaction Time tasks). First, a reanalysis of Wulf and collaborator's studies, dealing with implicit motor learning, made it possible to highlight methodological problems and potential biases that provide alternative explanations for the apparent implicit learning obtained in their continuous tracking experiments. Indeed, by respecting a more rigorous methodology, it appears that it is quite difficult to obtain such learning in a continuous task. This led us to try to understand why it was easier to draw benefit from a repetition in a discret…
Cooperation between Different CRISPR-Cas Types Enables Adaptation in an RNA-Targeting System
2021
CRISPR-Cas systems are immune systems that protect bacteria and archaea against their viruses, bacteriophages. Immunity is achieved through the acquisition of short DNA fragments from the viral invader’s genome.