A Constrained EM Algorithm for Independent Component Analysis

We introduce a novel way of performing independent component analysis using a constrained version of the expectation-maximization (EM) algorithm. The source distributions are modeled as D one-dimensional mixtures of gaussians. The observed data are modeled as linear mixtures of the sources with additive, isotropic noise. This generative model is fit to the data using constrained EM. The simpler “soft-switching” approach is introduced, which uses only one parameter to decide on the sub- or supergaussian nature of the sources. We explain how our approach relates to independent factor analysis

Politica mondiale e pathos nazionale

II concetto di "nazione" rimanda sempre alla relazione con la "potenza" politica; ed evidentemente, se "nazionale" deve significare qualcosa di unitario, allora "nazionale" sarà anche uno speciale pathos che, in un gmppo di uomini uniti dalla comunità di lingua, dalla confessione, dai costumi o dai destini si ricollega all'idea di una propria organizzazione politica rivolta alla "potenza", già esistente o auspicata; e ciò tanto più specificamente quanto più l'accento viene posto sulla "potenza". Di fronte alla molteplicità di significato, empiricamente riscontrabile, del concetto di valore costituito dall'idea di nazione", una casistica sociologica dovrebbe sviluppare un'analisi di tutte le singole forme di sentimenti di comunanza e di solidarietà, per individuare le condizioni in cui esse si producono e le loro conseguenze sull'agire di comunità dei partecipanti. Questa analisi non può essere tentata in questa sede. Piuttosto ci interessa esaminare ancora un po' più da vicino un altro fenomeno, cioè il fatto che l'idea di "nazione" si trova, nei suoi portatori, in relazioni molto strette con determinati interessi di "prestigio"

1985-86 UNOPA Executive Board Minutes

by Gesche Schifferdecker and Helen May “Global history” has become a prominent subject in North American and European academia claims Sanjay Subrahmanyam from the University of California in his essay “Global Intellectual History Beyond Hegel and Marx“. "But is histoire globale or ‘global history’ so transparent after all as a description? The mere fact that a word appears in myriad book and article titles is no real guarantee of anything” (127). In his review of the anthology "Global Intelle..

Collective treatment of the giant resonances in spherical nuclei

In a collective treatment the energies of the giant resonances are given by the boundary conditions at the nuclear surface, which is subject to vibration in spherical nuclei. The general form of the coupling between these two collective motions is given by angular-momentum and parity conservation. The coupling constants are completely determined within the hydrodynamical model. In the present treatment the influence of the surface vibrations on the total photon-absorption cross section is calculated. It turns out that in most of the spherical nuclei this interaction leads to a pronounced structure in the cross section. The agreement with the experiments in medium-heavy nuclei is striking; many of the experimental characteristics are reproduced by the present calculations. In some nuclei, however, there seem to be indications of single-particle excitations which are not yet contained in this work

A Convergent Finite Element Scheme for the Q-Tensor Model of Liquid Crystals Subjected to an Electric Field

We study the Landau-de Gennes Q-tensor model of liquid crystals subjected to an electric field and develop a fully discrete numerical scheme for its solution. The scheme uses a convex splitting of the bulk potential, and we introduce a truncation operator for the Q-tensors to ensure well-posedness of the problem. We prove the stability and well-posedness of the scheme. Finally, making a restriction on the admissible parameters of the scheme, we show that up to a subsequence, solutions to the fully discrete scheme converge to weak solutions of the Q-tensor model as the time step and mesh are refined. We then present numerical results computed by the numerical scheme, among which, we show that it is possible to simulate the Fr\'eedericksz transition with this scheme

Confucianisme et puritanisme

La meilleure manière peut-être de situer ce qui vient d’être dit dans notre perspective d’ensemble serait d’élucider le rapport entre le rationalisme confucianiste – cette appellation en effet convient bien au confucianisme – et le rationalisme qui nous est géographiquement et historiquement le plus proche : le rationalisme protestant. Le niveau de rationalisation qu’exprime une religion peut être évalué, avant tout, selon deux critères, qui du reste sont liés entre eux à plus d’un titre. D’a..