From Methods to Images

This paper presents a system for automatically selecting images in an image database to be used as illustrations of an image method or analysis process. This problem is related to the teleteaching of image processing which uses already implemented libraries of algorithms. This is in the context of a teleteaching European project. We first give a Bayesian approach to this problem, by using an image basis. Then we show how to use the Haar transform for this purpose. Finally we give examples and discuss our approach. Received: June 8, 1998; revised December 17, 1998     

Development of an automated experimental setup for the study of ionic-exchange kinetics. Application to the ionic adsorption, equilibrium attainment and dissolution of apatite compounds

An ion-selective electrode and microcomputer-based experimental setup for the study of ionic-exchange kinetics between a powdered solid and the solution is described. The equipment is composed of easily available commercial devices and a data acquisition and regularization computer program is presented. The system, especially developed to investigate the ionic adsorption, equilibrium attainment and dissolution of hard mineralized tissues, provides good reliable results by taking into account the volume changes of the reacting solution and the electrode behaviour under different experimental conditions, and by avoiding carbonation of the solution. A second computer program, using the regularized data and the experimental parameters, calculates the quantities of protons consumed and calcium released in the case of equilibrium attainment and dissolution of apatite-like compounds. Finally, typical examples of ion-exchange and dissolution kinetics under constant pH of enamel and synthetic hydroxyapatite are examined.     

Stochastic simulation of Taylor's dispersion in the airways

A stochastic simulation was devised in order to obtain a more correct solution of the phenomenon of convection combined with axial and radial diffusion, which is also called Taylor's dispersion, as it could occur in the pulmonary tract. The fit with Aris' moments which can be deemed as a reference since they are obtained analytically without approximation, was quite good. On the other hand, Taylor's solution usually led to large discrepancies with these moments. Taylor's stipulation that his solution be used only under certain conditions was therefore confirmed. This solution is not applicable in the lungs.     

Multicast Parametric Synchronous Sampling of 320-Gb/s Return-to-Zero Signal

Technology for simultaneous demultiplexing of subrate tributaries is described and applied to 320-Gb/s return-to-zero input. The parametric architecture is scalable with respect to processed input rate and relies on cascaded all-optical multicasting and subrate sampling. Processing of 320-Gb/s input was achieved by creating eight channel copies, followed by a 20-THz-wide parametric gate. Multicasting was based on a self-seeded two-pump broadband fiber-optic parametric amplifier. The architecture was used to demonstrate error-free parallel demultiplexing of eight 320-Gb/s tributary channels at 40 Gb/s.     

EDELWEISS Read-out Electronics and Future Prospects

The read-out electronics of the EDELWEISS-II experiment is presented. Its implementation has been guided by two important design choices. The first one is putting cold electronics far from the detectors in order to attenuate possible background sources from electronic components. It implies strong constraints on noise optimization, line stray capacitance and thermal load. The second one is acquisition of fully digitized signals to minimize the E.M. noises and to take full advantage of digital processing possibilities for filtering and triggering. The resulting amplification scheme is presented for both ionization and heat channel, as well as performances of the full read-out scheme. Future prospects about the coming EDELWEISS-III experiment electronics are also discussed. This updated design takes advantage of the experience gained in previous steps of the experiment while aiming at fulfilling specific constraints of a future ton-scale experiment.     

Low Distortion Multicasting of an Analog Signal by Self-Seeded Parametric Mixer

We present a linear multicast of an analog signal in a two-pump self-seeded parametric device. The linearity of the parametric multicasting is assessed by two-tone measurements of the third-order intermodulation products and radio-frequency spectral analysis. Experimental results show the linear behavior of a four-photon mixer over a wide range of input signal power.      

Translation of Gbps Phase-Modulated Optical Signal From Near-Infrared to Visible Band

Phase-coded optical signal was spectrally translated from the conventional near-infrared communication band to the visible band. Spectrally narrow 780-nm pump was combined with phase-modulated 1575-nm signal in a small core photonic crystal fiber (PCF), to generate 518-nm idler through parametric process. The phase-modulated idler carrying 1-Gbps information was received in an error-free manner. The onset of the stimulated Brillouin scattering (SBS) was found to be a major limitation for conversion efficiency and noise performance. The SBS effect and the birefringence properties of the small core PCF were studied at both 780 and 1550 nm and their impact on the parametric process was analyzed.