Search results for " norma"
showing 10 items of 623 documents
A note on the exterior centralizer
2009
The notion of the exterior centralizer \({C_G^{^\wedge}(x)}\) of an element x of a group G is introduced in the present paper in order to improve some known results on the non-abelian tensor product of two groups. We study the structure of G by looking at that of \({C_G^{^\wedge}(x)}\) and we find some bounds for the Schur multiplier M(G) of G.
On the Efficiency of Affine Invariant Multivariate Rank Tests
1998
AbstractIn this paper the asymptotic Pitman efficiencies of the affine invariant multivariate analogues of the rank tests based on the generalized median of Oja are considered. Formulae for asymptotic relative efficiencies are found and, under multivariate normal and multivariatetdistributions, relative efficiencies with respect to Hotelling'sT2test are calculated.
Chiarezza normativa e certezza del diritto nell'attività del Comitato per la legislazione del primo biennio (1998-1999)
2004
Sempre più negli ordinamenti contemporanei si registra un legame tra l'uso delle diverse fonti normative e gli equilibri della forma di governo. La crescita del peso dell'esecutivo, infatti, si accompagna ad una crescita dei poteri normativi del governo, che mette in luce l'ulteriore esigenza di procedere ad una semplificazione dell'ordinamento e di garantire la chiarezza dei suoi atti. A tale scopo è intervenuta la modifica del regolamento della Camera dei deputati del 1998, che ha riformato e ridefinito l'attività di istruttoria legislativa, svolta dalle Commissioni competenti per materia nel corso del procedimento legislativo; ma sopratutto ha introdotto un nuovo organo, il Comitato per …
Topology-based goodness-of-fit tests for sliced spatial data
2023
In materials science and many other application domains, 3D information can often only be extrapolated by taking 2D slices. In topological data analysis, persistence vineyards have emerged as a powerful tool to take into account topological features stretching over several slices. In the present paper, we illustrate how persistence vineyards can be used to design rigorous statistical hypothesis tests for 3D microstructure models based on data from 2D slices. More precisely, by establishing the asymptotic normality of suitable longitudinal and cross-sectional summary statistics, we devise goodness-of-fit tests that become asymptotically exact in large sampling windows. We illustrate the test…
Appropriate kernels for Divisive Normalization explained by Wilson-Cowan equations
2018
The interaction between wavelet-like sensors in Divisive Normalization is classically described through Gaussian kernels that decay with spatial distance, angular distance and frequency distance. However, simultaneous explanation of (a) distortion perception in natural image databases and (b) contrast perception of artificial stimuli requires very specific modifications in classical Divisive Normalization. First, the wavelet response has to be high-pass filtered before the Gaussian interaction is applied. Then, distinct weights per subband are also required after the Gaussian interaction. In summary, the classical Gaussian kernel has to be left- and right-multiplied by two extra diagonal ma…
On the Computation of Symmetrized M-Estimators of Scatter
2016
This paper focuses on the computational aspects of symmetrized Mestimators of scatter, i.e. the multivariate M-estimators of scatter computed on the pairwise differences of the data. Such estimators do not require a location estimate, and more importantly, they possess the important block and joint independence properties. These properties are needed, for example, when solving the independent component analysis problem. Classical and recently developed algorithms for computing the M-estimators and the symmetrized M-estimators are discussed. The effect of parallelization is considered as well as new computational approach based on using only a subset of pairwise differences. Efficiencies and…
Co-citation Percentile Rank and JYUcite : a new network-standardized output-level citation influence metric and its implementation using Dimensions A…
2022
AbstractJudging value of scholarly outputs quantitatively remains a difficult but unavoidable challenge. Most of the proposed solutions suffer from three fundamental shortcomings: they involve (i) the concept of journal, in one way or another, (ii) calculating arithmetic averages from extremely skewed distributions, and (iii) binning data by calendar year. Here, we introduce a new metric Co-citation Percentile Rank (CPR), that relates the current citation rate of the target output taken at resolution of days since first citable, to the distribution of current citation rates of outputs in its co-citation set, as its percentile rank in that set. We explore some of its properties with an examp…
Le travail, au-delà de l'évaluation : normes et résistances
2018
National audience; Certains milieux de travail connaissent une véritable inflation des normes. Leurs finalités sont multiples : instaurer de la transparence, garantir au « client » un service de qualité, orienter et contrôler les comportements, responsabiliser les acteurs et les inciter à « l'excellence », mieux évaluer le personnel. En constituant un véritable corset, voire un carcan, ces normes peuvent empêcher les salariés de réaliser un travail de qualité, être une source de démotivation - voire de souffrance au travail - et fragiliser les collectifs de travail en place. Elles peuvent aussi générer des actions de résistance, individuelles et/ou collectives. Damien Collard invite le lect…
Finding condensed descriptions for multi-dimensional data.
1976
Abstract We describe two programs that may be used to find condensed descriptions for data available in a contingency table or in a covariance matrix in the case that these data follow a multinomial or a multivariate normal distribution, respectively. The programs perform a stepwise model search among multiplicative models by computing appropriate likelihood-ratio test statistics.
Contribution to variational analysis : stability of tangent and normal cones and convexity of Chebyshev sets
2014
The aim of this thesis is to study the following three problems: 1) We are concerned with the behavior of normal cones and subdifferentials with respect to two types of convergence of sets and functions: Mosco and Attouch-Wets convergences. Our analysis is devoted to proximal, Fréchet, and Mordukhovich limiting normal cones and subdifferentials. The results obtained can be seen as extensions of Attouch theorem to the context of non-convex functions on locally uniformly convex Banach space. 2) For a given bornology β on a Banach space X we are interested in the validity of the following "lim inf" formula (…).Here Tβ(C; x) and Tc(C; x) denote the β-tangent cone and the Clarke tangent cone to …