Conception of an E-learning scheme at the University of Algarve

With the proliferation of the Internet use, a growth of e-learning courses has been verified. We arrived to the moment where it is not enough for Universities to have standard courses to offer to the students, because there is an increasing population which tends to choose his formation according to their objectives, styles, needs and learning preferences (the student profile). This way, the universities are faced with a new challenge, which is to offer, together with the standard courses, modules specially tailored to the user desires, based on the identification of the customers needs. In this paper, a model for the distance formation through Internet is discussed, that is being developed in the University of Algarve, which makes possible each individual to learn in agreement with his/her profile

Laser excitation of the 1s-hyperfine transition in muonic hydrogen

The CREMA collaboration is pursuing a measurement of the ground-state hyperfine splitting (HFS) in muonic hydrogen ($\mu$p) with 1 ppm accuracy by means of pulsed laser spectroscopy to determine the two-photon-exchange contribution with $2\times10^{-4}$ relative accuracy. In the proposed experiment, the $\mu$p atom undergoes a laser excitation from the singlet hyperfine state to the triplet hyperfine state, {then} is quenched back to the singlet state by an inelastic collision with a H$_2$ molecule. The resulting increase of kinetic energy after the collisional deexcitation is used as a signature of a successful laser transition between hyperfine states. In this paper, we calculate the combined probability that a $\mu$p atom initially in the singlet hyperfine state undergoes a laser excitation to the triplet state followed by a collisional-induced deexcitation back to the singlet state. This combined probability has been computed using the optical Bloch equations including the inelastic and elastic collisions. Omitting the decoherence effects caused by {the laser bandwidth and }collisions would overestimate the transition probability by more than a factor of two in the experimental conditions. Moreover, we also account for Doppler effects and provide the matrix element, the saturation fluence, the elastic and inelastic collision rates for the singlet and triplet states, and the resonance linewidth. This calculation thus quantifies one of the key unknowns of the HFS experiment, leading to a precise definition of the requirements for the laser system and to an optimization of the hydrogen gas target where $\mu$p is formed and the laser spectroscopy will occur.Comment: 21 pages, 4 figure

A Matlab toolbox for simulating transputer and digital signal processors applications

The performance demands of modern control and signal processing systems is increasing beyond the capacity of conventional sequential processors, requiring parallel processing solutions to satisfy the real-time requirements. In this paper a new version of Matlab toolbox for simulating homogeneous systems built with Inmos transputers or digital signal processors is presented. This toolbox extended the capabilities of a previous approach. Its development aims to help the designer to compare, effortlessly, the performance of alternative parallel solutions, and also to monitor the program execution, within each processing node. This simulator is under further development to extend its applicability to parallel heterogeneous systems. Copyright (C) 1998 IFAC

Student model for an E-learning scheme

With the proliferation of the Internet use, a growth of e-learning courses has been verified. We arrived to the moment where it is not enough for Universities to have standard courses to offer to the students, because there is an increasing population which tends to choose his formation according to their objectives, styles, needs and learning preferences (the student profile). This way, the universities are faced with a new challenge, which is to offer, together with the standard courses, modules specially tailored to the user desires, based on the identification of the customers needs. In this paper, the first step for the creation of a student model for an e-learning scheme that is being developed in the University of Algarve is described. To achieve this goal, a series of tasks have been undertaken, in order to gather information of a representative group, and subsequent treatment of the gathered data, so that it can be integrated in the tool of e-learning available in University of Algarve under the name of “Tutoria electrónica”

Diffusion of muonic hydrogen in hydrogen gas and the measurement of the 1ss hyperfine splitting of muonic hydrogen

The CREMA collaboration is pursuing a measurement of the ground-state hyperfine splitting (HFS) in muonic hydrogen ($\mu$p) with 1 ppm accuracy by means of pulsed laser spectroscopy. In the proposed experiment, the $\mu$p atom is excited by a laser pulse from the singlet to the triplet hyperfine sub-levels, and is quenched back to the singlet state by an inelastic collision with a H$_2$ molecule. The resulting increase of kinetic energy after this cycle modifies the $\mu$p atom diffusion in the hydrogen gas and the arrival time of the $\mu$p atoms at the target walls. This laser-induced modification of the arrival times is used to expose the atomic transition. In this paper we present the simulation of the $\mu$p diffusion in the H$_2$ gas which is at the core of the experimental scheme. These simulations have been implemented with the Geant4 framework by introducing various low-energy processes including the motion of the H$_2$ molecules, i.e. the effects related with the hydrogen target temperature. The simulations have been used to optimize the hydrogen target parameters (pressure, temperatures and thickness) and to estimate signal and background rates. These rates allow to estimate the maximum time needed to find the resonance and the statistical accuracy of the spectroscopy experiment