On the relationship between bilevel decomposition algorithms and direct interior-point methods

Engineers have been using bilevel decomposition algorithms to solve certain nonconvex large-scale optimization problems arising in engineering design projects. These algorithms transform the large-scale problem into a bilevel program with one upperlevel problem (the master problem) and several lower-level problems (the subproblems). Unfortunately, there is analytical and numerical evidence that some of these commonly used bilevel decomposition algorithms may fail to converge even when the starting point is very close to the minimizer. In this paper, we establish a relationship between a particular bilevel decomposition algorithm, which only performs one iteration of an interior-point method when solving the subproblems, and a direct interior-point method, which solves the problem in its original (integrated) form. Using this relationship, we formally prove that the bilevel decomposition algorithm converges locally at a superlinear rate. The relevance of our analysis is that it bridges the gap between the incipient local convergence theory of bilevel decomposition algorithms and the mature theory of direct interior-point methods

Measuring inequality in a region: a SAM approach

In this paper, we apply SAM linear models to the economy in a Spanish region, Extremadura, from the usual household disaggregation of these matrices. The analysis aims to some issues related to income distribution. To achieve these goals, some relative multipliers are computed and we propose different simulations based on final demand and income transfers. Finally, we also compute the standard statistical measures of inequality and show how these measures change if different transfer policies are applied. JEL CODES: C69, D31, D59, H59

On the intrinsic and the spatial numerical range

For a bounded function $f$ from the unit sphere of a closed subspace $X$ of a Banach space $Y$, we study when the closed convex hull of its spatial numerical range $W(f)$ is equal to its intrinsic numerical range $V(f)$. We show that for every infinite-dimensional Banach space $X$ there is a superspace $Y$ and a bounded linear operator $T:X\longrightarrow Y$ such that $\bar{co} W(T)\neq V(T)$. We also show that, up to renormig, for every non-reflexive Banach space $Y$, one can find a closed subspace $X$ and a bounded linear operator $T\in L(X,Y)$ such that $\bar{co} W(T)\neq V(T)$. Finally, we introduce a sufficient condition for the closed convex hull of the spatial numerical range to be equal to the intrinsic numerical range, which we call the Bishop-Phelps-Bollobas property, and which is weaker than the uniform smoothness and the finite-dimensionality. We characterize strong subdifferentiability and uniform smoothness in terms of this property.Comment: 12 page

Retuning the radio astronomical search for axion dark matter with neutron stars

Primary charges multiply in the magnetosphere of neutron stars by electromagnetic cascade. This is accounted for the first time when computing the flux generated by axion-photon resonance, noting: (i) axions of up to dozens of meV of mass mix in the magnetized plasma; (ii) radio signal from isolated stars of inferable multiplicity factor is undetectable, which could extend up to infrared; (iii) observation of Galactic populations is also unpromising, as the boost is exiguous; (iv) telescopes could yet be sensitive to gravitational focusing of dark matter, e.g., SGR 1745-2900 orbiting Sgr A*.Comment: 9 pages, 1 figur

Model Based Development of Quality-Aware Software Services

Modelling languages and development frameworks give support for functional and structural description of software architectures. But quality-aware applications require languages which allow expressing QoS as a first-class concept during architecture design and service composition, and to extend existing tools and infrastructures adding support for modelling, evaluating, managing and monitoring QoS aspects. In addition to its functional behaviour and internal structure, the developer of each service must consider the fulfilment of its quality requirements. If the service is flexible, the output quality depends both on input quality and available resources (e.g., amounts of CPU execution time and memory). From the software engineering point of view, modelling of quality-aware requirements and architectures require modelling support for the description of quality concepts, support for the analysis of quality properties (e.g. model checking and consistencies of quality constraints, assembly of quality), tool support for the transition from quality requirements to quality-aware architectures, and from quality-aware architecture to service run-time infrastructures. Quality management in run-time service infrastructures must give support for handling quality concepts dynamically. QoS-aware modeling frameworks and QoS-aware runtime management infrastructures require a common evolution to get their integration

Linear multipliers applied to a social accounting matrix for Extremadura

The topics related to the income distribution are specially interesting when we try to measure the social and economic impacts of a economic policy given decission. When a strategy of balanced development is tried to imply in a given country or region, inequality, poverty, unemployment, etc, not only economic growth, are important topics. The study is going to be focused in Extremadura, one of the less developped regions in Spain. We'll use a Social Accounting Matrix made by the authors, and it shall let us to show the circular flow of income and the relationships between the accounts included in tha SAM. An exercise of linear multipliers on the matrix shall be presented to get outcomes about the effects of several exogenous shocks on the endogenous accounts that we'll want to choose. We'll compute different types of multipliers: production, income, employment, etc., and we'll try to show different ways to get a balanced endogenous development for Extremadura, and which decissions are better to get it.

Effects of the Tax on Retail Sales of Some Fuels on a regional economy: a computable general equilibrium approach

This paper simulates the effects on the economy of Extremadura that are produced by a new tax on retail sales of some fuels. A computable general equilibrium model involving various labour market scenarios is employed as a modelling framework. Model parameters are obtained by calibration, using a social accounting matrix for Extremadura updated to the year 2000. Further, we also include an additional simulation in which a hypothetical regional tax rate, to finance environmental policies, is considered. This second simulation assumes constant fiscal revenues. The results of the first simulation show that the effects of this tax are modest. The simulation shows household welfare losses, decreasing activity levels and generalised price reductions, except in production sectors more directly linked to the oil products sector. In addition, we also observe that this hypothetical additional regional fuel tax rate would reinforce the effects produced by the national tax rate.Tax on retail sales of some fuels, computable general equilibrium models, social accounting matrices, fiscal policy.

Intervención psicológica en un equipo de baloncesto

El trabajo psicológico con un equipo deportivo conlleva mayor dificultad que el trabajo que se desarrolla con disciplinas individuales (Buceta, 1996). En general, las diferencias de trabajo en las intervenciones colectivas pueden ser: Una mayor cantidad de personas en el staff técnico para coordinarse. Un mayor número de problemas a la vez, en ocasiones más complejos que en intervenciones individualizadas. Un proceso de intervención con mayores limitaciones (sujeto a una estructura temporal marcada por las ligas, tiempo más limitado en los entrenamientos, número de deportistas para trabajar, etc.). O las necesidades económicas de los propios psicólogos deportivos (el trabajar con intervenciones individuales permite la incorporación de un mayor número de estas, sin embargo, ser un miembro más del cuerpo técnico limita las intervenciones individuales)