Implementación de aplicaciones y herramientas de post-procesamiento de imágenes médicas vía web

Con la creciente generación de resonancias magnéticas, los servicios de radiología necesitan aplicaciones que les faciliten el trabajo de acceso remoto a los datos y a las herramientas que utilicen para la extracción de datos para realizar sus diagnósticos. El objetivo de este proyecto es el de estudiar e integrar en la plataforma web del grupo de Imagen Médica del PIC llamada PICNIC (PIC NeuroImaging Center) un conjunto de aplicaciones para el estudio y procesamiento de neuroimagen con la implementación de herramientas software en la plataforma grid del PIC.

A parameter-free approach for solving combinatorial optimization problems through biased randomization of efficient heuristics

This paper discusses the use of probabilistic or randomized algorithms for solving combinatorial optimization problems. Our approach employs non-uniform probability distributions to add a biased random behavior to classical heuristics so a large set of alternative good solutions can be quickly obtained in a natural way and without complex conguration processes. This procedure is especially useful in problems where properties such as non-smoothness or non-convexity lead to a highly irregular solution space, for which the traditional optimization methods, both of exact and approximate nature, may fail to reach their full potential. The results obtained are promising enough to suggest that randomizing classical heuristics is a powerful method that can be successfully applied in a variety of cases.

On the stability of the optimal value and the optimal set in optimization problems

The paper develops a stability theory for the optimal value and the optimal set mapping of optimization problems posed in a Banach space. The problems considered in this paper have an arbitrary number of inequality constraints involving lower semicontinuous (not necessarily convex) functions and one closed abstract constraint set. The considered perturbations lead to problems of the same type as the nominal one (with the same space of variables and the same number of constraints), where the abstract constraint set can also be perturbed. The spaces of functions involved in the problems (objective and constraints) are equipped with the metric of the uniform convergence on the bounded sets, meanwhile in the space of closed sets we consider, coherently, the Attouch-Wets topology. The paper examines, in a unified way, the lower and upper semicontinuity of the optimal value function, and the closedness, lower and upper semicontinuity (in the sense of Berge) of the optimal set mapping. This paper can be seen as a second part of the stability theory presented in [17], where we studied the stability of the feasible set mapping (completed here with the analysis of the Lipschitz-like property).

On slicewise monotone parameterized problems and optimal proof systems for TAUT

"Vegeu el resum a l'inici del document del fitxer adjunt"

Application of the combined integral method to Stefan problems

In this paper we present a new, accurate form of the heat balance integral method, termed the Combined Integral Method (or CIM). The application of this method to Stefan problems is discussed. For simple test cases the results are compared with exact and asymptotic limits. In particular, it is shown that the CIM is more accurate than the second order, large Stefan number, perturbation solution for a wide range of Stefan numbers. In the initial examples it is shown that the CIM reduces the standard problem, consisting of a PDE defined over a domain specified by an ODE, to the solution of one or two algebraic equations. The latter examples, where the boundary temperature varies with time, reduce to a set of three first order ODEs.

Improving the accuracy of heat balance integral methods applied to thermal problems with time dependent boundary conditions

In this paper the two main drawbacks of the heat balance integral methods are examined. Firstly we investigate the choice of approximating function. For a standard polynomial form it is shown that combining the Heat Balance and Refined Integral methods to determine the power of the highest order term will either lead to the same, or more often, greatly improved accuracy on standard methods. Secondly we examine thermal problems with a time-dependent boundary condition. In doing so we develop a logarithmic approximating function. This new function allows us to model moving peaks in the temperature profile, a feature that previous heat balance methods cannot capture. If the boundary temperature varies so that at some time t & 0 it equals the far-field temperature, then standard methods predict that the temperature is everywhere at this constant value. The new method predicts the correct behaviour. It is also shown that this function provides even more accurate results, when coupled with the new CIM, than the polynomial profile. Analysis primarily focuses on a specified constant boundary temperature and is then extended to constant flux, Newton cooling and time dependent boundary conditions.

An axiomatic justification of mediation in bankruptcy problems.

This paper provides a natural way of reaching an agreement between two prominent proposals in a bankruptcy problem. Particularly, using the fact that such problems can be faced from two different points of views, awards and losses, we justify the average of any pair of dual bankruptcy rules through the definition a double recursive process. Finally, by considering three posible sets of equity principles that a particular society may agree on, we retrieve the average of old and well known bankruptcy rules, the Constrained Equal Awards and the Constrained Equal Losses rules, Piniles’ rule and its dual rule, and the Constrained Egalitarian rule and its dual rule. Keywords: Bankruptcy problems, Midpoint, Bounds, Duality, Recursivity. JEL classification: C71, D63, D71.

A way to play bankruptcy problems.

The commitment among agents has always been a difficult task, especially when they have to decide how to distribute the available amount of a scarce resource among all. On the one hand, there are a multiplicity of possible ways for assigning the available amount; and, on the other hand, each agent is going to propose that distribution which provides her the highest possible award. In this paper, with the purpose of making this agreement easier, firstly we use two different sets of basic properties, called Commonly Accepted Equity Principles, to delimit what agents can propose as reasonable allocations. Secondly, we extend the results obtained by Chun (1989) and Herrero (2003), obtaining new characterizations of old and well known bankruptcy rules. Finally, using the fact that bankruptcy problems can be analyzed from awards and losses, we define a mechanism which provides a new justification of the convex combinations of bankruptcy rules. Keywords: Bankruptcy problems, Unanimous Concessions procedure, Diminishing Claims mechanism, Piniles’ rule, Constrained Egalitarian rule. JEL classification: C71, D63, D71.

La Primavera Àrab, primera gran crisi de l’acció exterior Post-Lisboa: la visibilitat, l’eficàcia i la coherència del nou marc institucional a prova

La reforma de Lisboa va establir un nou marc institucional en l'àmbit l'Acció Exterior de la Unió Europea. Un nou marc que ha de permetre a la UE consolidar-se com a actor global en el nou panorama internacional. S'espera que els canvis de Lisboa corregeixin algunes de les deficiències que la política exterior europea havia mostrat en crisis anteriors, mancances de visibilitat, eficàcia i coherència. Un any després de la seva entrada en vigor, les revoltes dels països àrabs durant la primavera de 2011 són la primera gran crisi que l'Acció Exterior post-Lisboa ha d'afrontar i l'oportunitat per avaluar si s'ha aconseguit corregir aquestes mancances del passat.

Análisis de supervivencia post-trasplante hepático por Cirrosis post-hepatitis C en pacientes coinfectados VIH/VHC, en comparación con monoinfectados por VHC.

La TARGA (terapia antirretroviral de gran activitat) ha camviat el pronóstic dels pacients infectats pel VIH. Actualment la cirrosi per VHC y el hepatocarcinoma son les principales causes de mort. El trasplantament hepátic (TH) es una indicació recent en aquests pacients. Objectius: Comparar la supervivència post-TH en pacients coinfectats VHC/VIH front a monoinfectats VHC. Conclusions: Els resultats preliminars en el nostre centre son inferiors en pacients coinfectats en comparació amb els controls, que podría ser degut a contraindicacions para el tractament antiviral i a una menor eficacia del mateix.

A Proportional Approach to Bankruptcy Problems with a guaranteed minimum

In a distribution problem, and specfii cally in bankruptcy issues, the Proportional (P) and the Egalitarian (EA) divisions are two of the most popular ways to resolve the conflict. The Constrained Equal Awards rule (CEA) is introduced in bankruptcy literature to ensure that no agent receives more than her claim, a problem that can arise when using the egalitarian division. We propose an alternative modi cation, by using a convex combination of P and EA. The recursive application of this new rule finishes at the CEA rule. Our solution concept ensures a minimum amount to each agent, and distributes the remaining estate in a proportional way. Keywords: Bankruptcy problems, Proportional rule, Equal Awards, Convex combination of rules, Lorenz dominance. JEL classi fication: C71, D63, D71.

Solidarity and uniform rules in bankruptcy problems

The idea of ensuring a guarantee (a minimum amount of the resources) to each agent has recently acquired great relevance, in both social and politi- cal terms. Furthermore, the notion of Solidarity has been treated frequently in redistribution problems to establish that any increment of the resources should be equally distributed taking into account some relevant characteris- tics. In this paper, we combine these two general concepts, guarantee and solidarity, to characterize the uniform rules in bankruptcy problems (Con- strained Equal Awards and Constrained Equal Losses rules). Keywords: Constrained Equal Awards, Constrained Equal Losses, Lower bounds, Bankruptcy problems, Solidarity. JEL classification: C71, D63, D71.

A New Approach for Bounding Awards in Bankruptcy Problems

The solution for the ‘Contested Garment Problem’, proposed in the Babylonic Talmud, suggests that each agent should receive at least some part of the resources whenever the demand overcomes the available amount. In this context, we propose a new method to define lower bounds on awards, an idea that has underlied the theoretical analysis of bankruptcy problems from its beginning (O’Neill, 1982) to present day (Dominguez and Thomson, 2006). Specifically, starting from the fact that a society establishes its own set of ‘Commonly Accepted Equity Principles’, our proposal ensures to each agent the smallest amount she gets according to all the admissible rules. As in general this new bound will not exhaust the estate, we analyze its recursive application for different sets of equity principles. Keywords: Bankruptcy problems, Bankruptcy rules, Lower bounds, Recursive process

Agile onboard : post-its virtuals

Agile onBoard és una aplicació basada en la idea d’un sistema de post-its virtuals per grups de treball d'una empresa que facin ús d'Scrum, amb la finalitat de veure fàcilment les tasques per projecte, la seva assignació de personal y el seu estat. A més a més, Agile onBoard ofereix possibilitats addicionals per l’usuari tals la personalització d'estats, creació de projectes o limitació de projectes per grups. És una aplicació senzilla d’utilitzar, i que no incorpora un seguit d’opcions i requisits que presenten altres alternatives que no fan més que dificultar i entorpir el senzill i directe procés d'escriure un post-it i penjar-lo a la pissarra tal i com es fa en un entorn real. L’aplicació està dissenyada seguint una estructura jeràrquica que defineix els permisos i les opcions que són accessibles a cada tipus d’usuari, per tal d’oferir una eina útil per tot tipus de projectes.