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The author offers a reflection on the question of Christian identity in a changing Europe. He points out that it was only as the number of practicing Christians in public life diminished that the question of the Christian identity of the continent arose. He questions the kinds of uncritical identification of European and Christian culture that arises in the fact of increased Islamic immigration. He surveys the principal options facing Christians and Christian culture as Europe faces an uncertain future.

Published: Nov-Dec 2017

L’article Democracy Promotion at a Local Level : Experiences, Perspectives and Policy of Swiss International Cooperation de Martin Dahinden présente une analyse fine et complexe de ce qui peut constituer une politique concrète et efficace d’aide à la démocratisation ; il en souligne les limites possibles, la complexité des niveaux d’intervention et la nécessité de la mettre en œuvre dans le cadre d’une société civile spécifique et d’enjeux de pouvoir locaux. Cette aide à la démocratisation s’...

The Internet and other communication networks are development tools, quite as important as educational, agricultural and training programmes. Information, Information Technologies and data networks have (and have had) a fundamental role in the development of ‘northern societal and cultural environments’, though the Internet is still seen by some people in developed countries simply as a pastime, as a new multimedia entertainment providing nice graphics and images. In a society sated with information, the need for Information and Information Technologies are perhaps not always fully appreciated. The role of networks as valuable development tools may therefore be better understood in the African context. The purpose ofthis article, however, is not only to point out the importance of electronic communication networks such as the Internet in helping the processes of development in Africa, but also to offer readers of the Africa Bibliography an up-to-date guide to the extent and kinds of connectivity currently operating or being planned in African countries, and to some of the problems – political, financial, technical – that the new information technology faces today.

Translation from "La laicité face à l'Islam" (Secularism confronts Islam), 2005

Roy Olivier. Vue d'ensemble. In: Cahiers du monde russe et soviétique, vol. 32, n°1, Janvier-mars 1991. En Asie Centrale soviétique Ethnies, nations, États. pp. 153-155.

The ability to design efficient distributed communications systems heavily depends on a proper understanding of the distortion incurred by their constituting elements. To this end, we study the mean squared reconstruction error behavior of the distributed Karhunen-Lo\`{e}ve transform. We provide a general formula to compute this distortion under asymptotic considerations in a pure approximation viewpoint. Using a simple illustrative example, we show how this approach allows to obtain closed-form formulas that permit to efficiently assess the performance of the distributed scheme.

We consider the task of recovering correlated vectors at a central decoder based on fixed linear measurements obtained by distributed sensors. Two different scenarios are considered: In the case of universal reconstruction, we look for a sensing and recovery mechanism that works for all possible signals, whereas in the case of almost sure reconstruction, we allow to have a small set (with measure zero) of unrecoverable signals. We provide achievability bounds on the number of samples needed for both scenarios. The bounds show that only in the almost sure setup can we effectively exploit the signal correlations to achieve effective gains in sampling efficiency. In addition, we propose an efficient and robust distributed sensing and reconstruction algorithm based on annihilating filters.

Hearing aids are electronic, battery-operated sensing devices which aim at compensating various kinds of hearing impairments by means of appropriate signal processing. Most of today's hearing aid systems consist of two appliances working independently of each other. However, collaboration using a wireless communication link would allow to improve the overall beamforming capability of the system, hence providing better rejection of interfering signals. In this paper, the problem is considered from an information-theoretic viewpoint. We provide the necessary theoretical background to precisely quantify the gain achieved by collaboration as a function of the communication bit-rate. The beamforming capability is then discussed for the setup considered in this work.

It is disclosed an acoustic tomography method to improve the time of flight estimation, said method comprising the steps of: sequentially triggering a set of N transmitters so as to generate a sequence of N acoustic waves through a volume being scanned; receiving each of said acoustic waves after transmission through said volume with a set of M receivers, which are called received signals; delaying by varying delays the N different said received signals that each receiver receives from the N different transmitters, and adding them together to form a new received signal, which is called transmit-beamformed signal for that receiver; delaying by varying delays the M different said transmit-beamformed signals for each receiver and adding them together at each receiver to form a new signal, which we call transmit-receive-beamformed signal.

Accurate calibration is a requirement of many array signal processing techniques. We investigate the calibration of a transducer array using time delays. We derive a strategy based on the mean square error criterion and discuss how time delays that are not available can be interpolated from existing ones. The proposed method is made robust to noise and model mismatch by means of a novel iterative technique for distance matrix denoising. The convergence of the method is proved. Finally, the accuracy of the proposed calibration algorithm is assessed both in simulated scenarios and using experimental data obtained from an ultrasound scanner designed for breast cancer detection.

Most space-time coding schemes can be classified either as non-coherent (decoding is performed without forming an explicit channel estimate) or coherent (decoding is performed conditioned upon a channel estimate as if it were the actual channel realisation). In this thesis, we consider a correlated quasi-static Rayleigh flat fading channel with additive white Gaussian noise. We prove that optimal non-coherent decoding can always be decomposed into a channel estimation step followed by a coherent decoding step. Surprisingly, the required estimators of this coherent approach do not in general minimise the mean square error between the estimated and actual channel realisation. We investigate the characteristics of these estimators and discuss their optimality.