Histogram packing, total variation, and lossless image compression

Publication in the conference proceedings of EUSIPCO, Toulouse, France, 200

Signal and System Approximation from General Measurements

In this paper we analyze the behavior of system approximation processes for stable linear time-invariant (LTI) systems and signals in the Paley-Wiener space PW_\pi^1. We consider approximation processes, where the input signal is not directly used to generate the system output, but instead a sequence of numbers is used that is generated from the input signal by measurement functionals. We consider classical sampling which corresponds to a pointwise evaluation of the signal, as well as several more general measurement functionals. We show that a stable system approximation is not possible for pointwise sampling, because there exist signals and systems such that the approximation process diverges. This remains true even with oversampling. However, if more general measurement functionals are considered, a stable approximation is possible if oversampling is used. Further, we show that without oversampling we have divergence for a large class of practically relevant measurement procedures.Comment: This paper will be published as part of the book "New Perspectives on Approximation and Sampling Theory - Festschrift in honor of Paul Butzer's 85th birthday" in the Applied and Numerical Harmonic Analysis Series, Birkhauser (Springer-Verlag). Parts of this work have been presented at the IEEE International Conference on Acoustics, Speech, and Signal Processing 2014 (ICASSP 2014

Adaptive Finite Difference Schemes Based On Interpolating Wavelets For Solving 2d Maxwell's Equations

[No abstract available]36003603Yee, K.S., Numerical Solution of Initial Boundary Value Problems Involving Maxwell's Equations in isotropic Media (1966) IEEE Trans. Antennas and Propagation, 14, pp. 302-307. , AprilHolmstrom, M., Wavelet based methods for time dependent PDEs (1997), Ph.D. dissertation, Uppsala UniversityP. Pinho, M. O. Domingues, P. J. S. G. Ferreira, S. M. Gomes, A. Gomide and J. R. Pereira' Interpolating wavelets and adaptive finite difference schemes for solving Maxwell's equations, 2006. Acceptd for publication on the IEEE Transactions on MagneticsDomingues, M.O., Ferreira, P.J.S.G., Gomes, S.M., Gomide, A., Pereira, J.R., Pinho, P., High Order Finite-Difference Schemes for Maxwell's Equations, 2006, , Submmite

Patterns of tick infestation and their Borrelia burgdorferi s.l. infection in wild birds in Portugal

Wild birds may act as reservoirs for zoonotic pathogens and may be mechanical carriers of pathogen infected vector ticks through long distances during migration. The aim of this study was to assess tick infestation patterns in birds in Portugal and the prevalence of tick infection by Borrelia burgdorferi s.l. using PCR techniques. Seven tick species were collected from birds including Haemaphysalis punctata, Hyalomma spp., Ixodes acuminatus, Ixodes arboricola, Ixodes frontalis, Ixodes ricinus and Ixodes ventalloi. We found that I. frontalis and Hyalomma spp. were the most common ticks infesting birds of several species and that they were widespread in Portugal. Turdus merula was the bird species that presented the highest diversity of infesting ticks and had one of the highest infestation intensities. B. burgdorferi s.l. was detected in 7.3% (37/505) of Ixodidae ticks derived from birds. The most common genospecies was Borrelia turdi (6.9%), detected in ticks collected from Parus major, T. merula and Turdus philomelos, but Borrelia valaisiana (0.2%) and one Borrelia sp. (0.2%) similar to Borrelia bissettii (96% of similarity of the flaB gene in Blastn) were also detected. This study contributed to a better knowledge of the Ixodidae tick fauna parasitizing birds in Western Europe and to the assessment of the prevalence of B. burgdorferi s.l. associated with birds and their ticks. © 2015 Elsevier GmbH. All rights reserved.This study was financially supported by the Portuguese Foundation for Science and Technology (FCT; SFRH/BPD/62898/2009)