Existence of a 2n FFT algorithm with a number of multiplications lower than 2n+1

First we give a decomposition of an FFT of length 2n into a number of one-dimensional polynomial products. If these products are computed with minimum multiplication algorithms, we show that the 2n FFT can be computed with less than 2n+1 nontrivial complex multiplications. A variation of this algorithm is also shown to give the same multiplication count as the `split-radix? FFT.     

Study and optimization of a flexible electrochromic device based on polyaniline

The synthesis of polyaniline (PANI) thin films was made onto commercially available  cm polyethylene terephthalate (PET)/indium tin oxide (ITO) substrates. By depositing a gold frame previously to the electrochemical PANI synthesis, homogeneous electrochromic PANI layers were obtained. Complete flexible cells could then be built by using a transparent gel electrolyte and a simple PET/ITO counter-electrode. Branched poly(ethyleneimine) (BPEI)-H₃PO₄ and polymethylemethacrylate (PMMA)-PC-LiClO₄ were both tested as electrolytes, but only the latter led to a non-degrading system when the device undergoes several switching potential steps. This flexible, middle-scale and inexpensive device enabled to get a 18% transmission contrast at 780 nm within 3 min.     

Toxocariasis and functional intestinal disorders. Presentation of 4 cases]

We report 4 cases of adults patients, suffering from irritable bowel syndrome, which had been attributed late to toxocariasis and for whom the treatment led to recovery. Hypereosinophilia was present only in 3 cases. These cases show that toxocariasis is not limited anymore to its two classical expressions: visceral larva migrans and ocular toxocariasis. So it is useful to think of it to confirm and treat it in the case of patients suffering from irritable bowel syndrome. This enables shorter diagnosis delay (14 months in average for our patients) and this is essential for therapeutic efficiency.     

A least mean squares blind equalization techniques for OFDM systems

Classical multicarrier systems based on the discrete Fourier transform(dft) make use of aguard interval (gi) in order to enable a low complexity equalization scheme. Thisguard interval consists of a redundant prefix cyclically appended to each block of modulated symbols so as to exploit the cyclic convolution property of thedft. Therefore, besides decreasing the useful transmitted symbol rate, this technique is very specific todft-basedofdm systems. In order to implement a digital modulator, an oversampled version of the continuous signal that would be produced by the all-analog ideal modulator is often computed. This amounts to appending null symbols to the block of symbols to be modulated. This work shows that forcing the presence of these null symbols at the appropriate places on the receiver side is sufficient to equalize the channel. Here, a linear equalizer is adapted by minimizing a quadratic criterion based on the energy of the subband signals that should be zero. Since no knowledge about theuseful data is required, this method performs blind equalization. Moreover, it requires neither a guard interval nor any reference symbol. As a result, for a given channel bitrate budget, the data rate is increased     

Ventral intraparietal area of the macaque: congruent visual and somatic response properties

Fusions of the human immunodeficiency virus type 1 (HIV-1) transactivator protein Tat to the green fluorescent protein (GFP) were used to study the intracellular localization, trafficking, and interactions of Tat in human cells. Tagging Tat with GFP did not change its nuclear localization or ability to act as a transactivator. Tat-GFP expressed at low levels was found in the nucleus, whereas overexpression resulted in nucleolar accumulation. A Tat-GFP hybrid protein containing in addition the HIV-1 Rev nuclear export signal (NES) localized predominantly to the cytoplasm. This shuttle protein, Tat-GFP-NES, transactivated the HIV-1 long terminal repeat. Thus a Tat molecule being only transiently present in the nucleus is active and nucleolar accumulation of Tat is not prerequisite for function. A coexpression assay previously used to define protein interaction domains in the HIV-1 Rev protein [R. H. Stauber, E. Afonina, S. Gulnik, J. Erickson, and G. N. Pavlakis (1998a). Virology 251, 38-48.] indicated that Tat exists predominantly as a monomer and does not form stable multimers with B23 in living cells. Using a heterokaryon fusion assay, we found that Tat-GFP was able to shuttle between the nucleus and the cytoplasm. Tat therefore has the potential to perform functions in the nucleus as well as in the cytoplasm.     

Image coding with an L(infinity) norm and confidence interval criteria

A new image coding technique based on an L(infinity)-norm criterion and exploiting statistical properties of the reconstruction error is investigated. The original image is preprocessed, quantized, encoded, and reconstructed within a given confidence interval. Two important classes of preprocessing, namely linear prediction and iterated filterbanks, are used. The approach is also shown to be compatible with previous techniques. The approach allows a great flexibility in that it can perform lossless coding as well as a controlled lossy one: specifications are typically that only p% the reconstructed pixels are different from the original ones.     

Subspace methods for the blind identification of multichannel FIRfilters

This paper addresses a problem arising in a context of digital communications. A digital source is transmitted through a continuous channel (the propagation medium), and several measurements are performed at the receiver, either by means of several sensors, or by oversampling the received signal compared to the emission rate. Given only these observations, the baseband equivalents of the corresponding channels have to be recovered. An orthogonality property between “signal” and “noise” subspaces is exploited to build some quadratic form whose minimization yields the desired estimates up to a scale factor. This is in the same spirit as recent works by Tong et al. (see Proc. 25th Asilomar Conf., p.856-860, 1991) but requires fewer computations. Numerical simulations demonstrate the performance of the proposed methods in a channel identification context     

Basefield transforms with the convolution property

We present a general framework for constructing transforms in the field of the input which have a convolution-like property. The construction is carried out over the reals, but is shown to be valid over more general fields. We show that these basefield transforms can be viewed as “projections” of the discrete Fourier transform (DFT). Furthermore, by imposing an additional condition on the projections, one may obtain self-inverse versions of the basefield transforms. Applying the theory to the real and complex fields, we show that the projection of the complex DFT results in the discrete combinational Fourier transform (DCFT) and that the imposition of the self-inverse condition on the DCFT yields the discrete Hartley transform (DHT). Additionally, we show that the method of projection may be used to derive efficient basefield transform algorithms by projecting standard FFT algorithms from the extension field to the basefield. Using such an approach, we show that many of the existing real Hartley algorithms are projections of well-known FFT algorithms