Stability estimate for the aligned magnetic field in a periodic quantum waveguide from dirichlet-to-neumann map

In this article, we study the boundary inverse problem of determining the aligned magnetic fiaeld appearing in the magnetic Schr\"odinger equation in a periodic quantum cylindrical waveguide. Provided that the Dirichlet-to-Neumann map of the magnetic Schr\"odinger equation. We prove a Holder stability estimate with respect to the Dirichlet-to-Neumann map, by means of the geometrical optics solutions of the magnetic Schrodinger equation.Comment: 19 pages. arXiv admin note: text overlap with arXiv:1306.6601 by other author

Efficient Decoding Algorithms for the Compute-and-Forward Strategy

We address in this paper decoding aspects of the Compute-and-Forward (CF) physical-layer network coding strategy. It is known that the original decoder for the CF is asymptotically optimal. However, its performance gap to optimal decoders in practical settings are still not known. In this work, we develop and assess the performance of novel decoding algorithms for the CF operating in the multiple access channel. For the fading channel, we analyze the ML decoder and develop a novel diophantine approximation-based decoding algorithm showed numerically to outperform the original CF decoder. For the Gaussian channel, we investigate the maximum a posteriori (MAP) decoder. We derive a novel MAP decoding metric and develop practical decoding algorithms proved numerically to outperform the original one

Constructions à verbes supports, collocations et locutions verbales

Se trata de mostrar que los tres conceptos corresponden a tres realidades lingüísticas diferentes y de sacar las características que los diferencian para poder realizar una descripción fundada en criterios formales que atañen a la sintaxis libre y a la sintaxis fijada. Si las construcciones con verbo soporte presentan una combinatoria libre y las colocaciones también, éstas últimas no se limitan por ello a las construcciones verbales y presentan empleos coocurrentes apropiados; lo que les aproxima en cierta manera a las locuciones verbales fijadas. Los puntos de referencia fundamentales que permiten distinguir estas tres construcciones son: los blocajes de las substituciones paradigmáticas y la solidaridad sintagmática correlativos a las restricciones sintácticas.Il s'agit de montrer que les trois concepts correspondent à trois réalités linguistiques différentes et de dégager les caractéristiques qui les distinguent pour en permettre une description fondée sur des critères formels relevant de la syntaxe libre et de la syntaxe figée. Si les constructions à verbes supports relèvent de la combinatoire libre et que les collocations le soient également, ces dernières ne se limitent pas pour autant aux constructions verbales et expriment des emplois co-occurrents appropriés ; ce qui les rapproche d'une certaine manière des locutions verbales figées. Blocage des substitutions paradigmatiques et solidarités syntagmatiques, corrélées avec des contraintes syntaxiques sont les repères fondamentaux servant à la distinction entre les trois constructions

Estimation of the Default Risk of Publicly Traded Canadian Companies

In this paper, we investigate the hybrid contingent claim approach with publicly traded Canadian companies listed on the Toronto Stock Exchange. Our goal is to assess how combining their continuous valuation by the market with the value given in their financial statements improves our ability to predict their probability of default. Our results indicate that the predicted structural probabilities of default (PDs from the structural model) contribute significantly to explaining default probabilities when PDs are included alongside the retained accounting variables. We also show that quarterly updates to the PDs add a large amount of dynamic information to explain the probabilities of default over the course of a year. This flexibility would not be possible with a reduced-form model. We also conducted a preliminary analysis of correlations between sructural probabilities of default for the firms in our database. Our results indicate that there are substantial correlations in the studied data.Default risk, public firm, structural model, reduced form model, hybrid model, probit model, Toronto Stock Exchange, correlations between default probabilities

Estimation of the Default Risk of Publicly Traded Canadian Companies

Two models of default risk are prominent in the financial literature: Merton's structural model and Altman's non-structural model. Merton's structural model has the benefit of being responsive, since the probabilities of default can continually be updated with the evolution of firms' asset values. Its main flaw lies in the fact that it may over- or underestimate the probabilities of default, since asset values are unobservable and must be extrapolated from the share prices. Altman's nonstructural model, on the other hand, is more precise, since it uses firms' accounting data-but it is less flexible. In this paper, the authors investigate the hybrid contingent claims approach with publicly traded Canadian companies listed on the Toronto Stock Exchange. The authors' goal is to assess how their ability to predict companies' probability of default is improved by combining the companies' continuous market valuation (structural model) with the value given in their financial statements (non-structural model). The authors' results indicate that the predicted structural probabilities of default (PDs from the structural model) contribute significantly to explaining default probabilities when PDs are included alongside the retained accounting variables in the hybrid model. The authors also show that quarterly updates to the PDs add a large amount of dynamic information to explain the probabilities of default over the course of a year. This flexibility would not be possible with a non-structural model. The authors conduct a preliminary analysis of correlations between structural probabilities of default for the firms in their database. Their results indicate that there are substantial correlations in the studied data.Debt management; Credit and credit aggregates; Financial markets; Recent economic and financial developments; Econometric and statistical methods