A second order cone formulation of continuous CTA model

The final publication is available at link.springer.comIn this paper we consider a minimum distance Controlled Tabular Adjustment (CTA) model for statistical disclosure limitation (control) of tabular data. The goal of the CTA model is to find the closest safe table to some original tabular data set that contains sensitive information. The measure of closeness is usually measured using l1 or l2 norm; with each measure having its advantages and disadvantages. Recently, in [4] a regularization of the l1 -CTA using Pseudo-Huber func- tion was introduced in an attempt to combine positive characteristics of both l1 -CTA and l2 -CTA. All three models can be solved using appro- priate versions of Interior-Point Methods (IPM). It is known that IPM in general works better on well structured problems such as conic op- timization problems, thus, reformulation of these CTA models as conic optimization problem may be advantageous. We present reformulation of Pseudo-Huber-CTA, and l1 -CTA as Second-Order Cone (SOC) op- timization problems and test the validity of the approach on the small example of two-dimensional tabular data set.Peer ReviewedPostprint (author's final draft

The Nature and Validity of the RKKY limit of exchange coupling in magnetic trilayers

The effects on the exchange coupling in magnetic trilayers due to the presence of a spin-independent potential well are investigated. It is shown that within the RKKY theory no bias nor extra periods of oscillation associated with the depth of the well are found, contrary to what has been claimed in recent works. The range of validity of the RKKY theory is also discussed.Comment: 10, RevTe

Anti de Sitter Gravity from BF-Chern-Simons-Higgs Theories

It is shown that an action inspired from a BF and Chern-Simons model, based on the $AdS_4$ isometry group SO(3, 2), with the inclusion of a Higgs potential term, furnishes the MacDowell-Mansouri-Chamseddine-West action for gravity, with a Gauss-Bonnet and cosmological constant term. The $AdS_4$ space is a natural vacuum of the theory. Using Vasiliev's procedure to construct higher spin massless fields in AdS spaces and a suitable star product, we discuss the preliminary steps to construct the corresponding higher-spin action in $AdS_4$ space representing the higher spin extension of this model. Brief remarks on Noncommutative Gravity are made.Comment: 6 pages, plain Tex, Revised. References are are adde

Harmonic Analysis Operators Associated with Multidimensional Bessel Operators

In this paper we establish that the maximal operator and the Littlewood-Paley g-function associated with the heat semigroup defined by multidimensional Bessel operators are of weak type (1,1). Also, we prove that Riesz transforms in the multidimensional Bessel setting are of strong type (p,p), for every $1<p<\infty$, and of weak type (1,1).Comment: 38 page

Hankel Multipliers of Laplace Transform Type

In this paper we prove that the Hankel multipliers of Laplace transform type on $(0,1)^n$ are of weak type (1,1). Also we analyze Lp-boundedness properties for the imaginary powers of Bessel operator on $(0,1)^n$.Comment: 32 page

Chronicle of a Pandemic Foretold. CEPS Policy Insights No 2020-05 / March 2020

In just a few weeks, COVID-19 appeared in China and quickly spread to the rest of the world, including Europe and the United States. Many have rushed to describe the outbreak as a ‘black swan’ – an unpredictable event with extremely severe consequences. However, COVID-19 was not only predictable ex post: it was amply predicted ex ante. This allows us to draw some preliminary lessons: • First, economic policy will need to shift from its current focus on efficiency, towards a greater emphasis on resilience and sustainability. • Second, a more centralised governance to address health emergencies is needed. • Third, Europe should create a centre for the prevention of large-scale risks. • Fourth, digital technologies, if handled with care, can be an important part of both a mitigation and a response strategy. • Fifth, Europe should improve its science advice and communication functions. Finally, there are many ways to pursue enhanced resilience and responsiveness, but not all of them are compatible with sustainability and democratic values. The challenge is to find an adequate policy mix, which safeguards individual rights and liberties, protects the economy, and at the same time strengthens government preparedness for cases of epidemics and pandemics