Assessing the asymmetric effects on branch rivalry of Spanish financial sector restructuring

Spanish financial institutions have been heavily affected by the banking crisis that began in 2008. Many of them, especially Spanish savings banks (or Cajas), had to merge with other institutions or had to be rescued. We address the question of up to what point the nature of competition in this sector has changed as a result of the crisis. Although institutions compete in many ways, we concentrate on their presence in the main street through bank branches open to the public (i.e., retail banking competition). Our measure of inter-firm rivalry is based on a geographical proximity measure that we calculate for the years 2008 (before the crisis) and 2012 (the last available data set). The technical approach is based on multidimensional unfolding, a methodology which allows us to graphically represent the asymmetric nature of such rivalry. These maps visualise the salient aspects of the system during the two dates analysed, and can be understood without a detailed technical knowledge.

     

Solving stochastic structural optimization problems by RSM-based stochastic approximation methods — gradient estimation in case of intermediate variables

Reliability-based structural optimization methods use mostly the following basic design criteria: I) Minimum weight (volume or costs) and II) high strength of the structure. Since several parameters of the structure, e.g. material parameters, loads, manufacturing errors, are not given, fixed quantities, but random variables having a certain probability distribution P,stochastic optimization problems result from criteria (I), (II), which can be represented by (1) $$\mathop {\min }\limits_{x \in D} F(x)withF(x): = Ef(\omega ,x).$$ Here,f=f(ω,x) is a function on ? ^r depending on a random element ω, “E” denotes the expectation operator andD is a given closed, convex subset of ? ^r . Stochastic approximation methods are considered for solving (1), where gradient estimators are obtained by means of the response surface methodology (RSM). Moreover, improvements of the RSM-gradient estimator by using “intermediate” or “intervening” variables are examined.     

Regularity, Local and Microlocal Analysis in Theories of Generalized Functions

We introduce a general context involving a presheaf and a subpresheaf ℬ of  . We show that all previously considered cases of local analysis of generalized functions (defined from duality or algebraic techniques) can be interpretated as the ℬ-local analysis of sections of  . But the microlocal analysis of the sections of sheaves or presheaves under consideration is dissociated into a “frequential microlocal analysis” and into a “microlocal asymptotic analysis”. The frequential microlocal analysis based on the Fourier transform leads to the study of propagation of singularities under only linear (including pseudodifferential) operators in the theories described here, but has been extended to some non linear cases in classical theories involving Sobolev techniques. The microlocal asymptotic analysis is a new spectral study of singularities. It can inherit from the algebraic structure of ℬ some good properties with respect to nonlinear operations.      

Reduced filament coupling in Bi(2223)/BaZrO3/Ag composite tapes

Multifilamentary Bi(2223)/Ag tapes often exhibit AC loss levels comparable to those measured in monofilamentary samples, which is partly due to the large coupling currents induced in the low resistive sheath material. Surrounding the individual filaments by electrically insulating barrier layers suppresses these currents and strongly reduces the coupling. We demonstrate this effect with various types of magnetic and self-field AC loss measurements on a series of Bi(2223)/BaZrO₃/Ag tapes. We also discuss the influence of barrier thickness, twist pitch length and filament arrangement on the measured losses in these composite conductors.     

Filament architectures in AC conductors: the influence of intergrowths

Filament isolation is an extremely important factor in multi-filamentary conductors, and attempts have been made to achieve this by incorporating a resistive oxide sheath around individual filaments. However, filament-bridging intergrowths have been observed in conductors with and without the resistive sheath. We present magnetisation results on BSCCO-2223/Ag conductors with different filament configurations, and analyse the data taking into account the effects of magnetic coupling between filaments. All samples studied display some degree of filament bridging.     

An algorithm recursively computing the exact fourier coefficients ofB-splines with nonequidistant knots

An algorithm has been developed for the numerical computation of the Fourier coefficients ofB-splinesM of arbitrary order and possibly nonequidistant and coincident knots. Ifk is the order ofM, then there is a matrixA, depending only onM such that each Fourier coefficient ofM can be obtained fromA by 0(k ²) operations. The computation ofA itself needs a number of operations of the order ofk ⁴. A program of the algorithm is given in an informal language and some numerical results are presented.

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Zusammenfassung Es wird ein Algorithmus beschrieben, der es gestattet, die Fourierkoeffizienten vonB-SplinefunktionenM von beliebiger Ordnung und mit möglicherweise nichtäquidistanten und zusammenfallenden Knoten numerisch exakt zu berechnen. Istk die Ordnung vonM, so gibt es eine nur vonM abhängige Matrix derart, dass jeder Fourierkoeffizient vonM ausA mit 0(k ²) Operationen erhalten werden kann. Die Berechnung vonA selbst benötigt eine Anzahl Operationen von der Ordnungk ⁴. Ein Rechenprogramm für den Algorithmus wird mit Hilfe einer informellen Programmiersprache (INFL) gegeben. Schliesslich werden die mit dem Programm berechneten Resultate von sechs verschiedenen Beispielen dargestellt.