38 research outputs found
Lâappropriation des potentialitĂ©s du dispositif de formation Moodle entre : investissement engagĂ© et rĂ©sistance des Ă©tudiants en contexte algĂ©rien
RĂ©sumĂ© : Il est indĂ©niable que la numĂ©risation a profondĂ©ment bouleversĂ© et mĂ©tamorphosĂ© le paysage de lâenseignement au supĂ©rieur. Lâadoption de lâE Learning a influĂ© considĂ©rablement la vocation des enseignants ainsi que celle des Ă©tudiants, ces derniers sont dĂ©sormais appelĂ©s Ă assurer un nouveau statut. La situation sanitaire imprĂ©vue a accentuĂ© le recours aux TIC qui est devenue un quasi- impĂ©ratif dans le secteur pĂ©dagogique. Parmi ces diapositifs numĂ©riques lâadoption de la plateforme pĂ©dagogique Moodle Ă lâuniversitĂ© constituait une issue pour maintenir la continuitĂ© des cours et faire face aux dĂ©fis posĂ©s par le passage soudain au nouveau scĂ©nario pĂ©dagogique. Ce choix avait pour objectif dâamĂ©liorer l'expĂ©rience d'apprentissage des Ă©tudiants et promouvoir leur rĂ©ussite acadĂ©mique. La prĂ©sente contribution vise Ă dĂ©montrer lâintĂ©rĂȘt accordĂ© par les Ă©tudiants de français de lâuniversitĂ© Larbi Ben MâHidi dâOum El Bouaghi au dispositif de formation Moodle. Pour ce faire, nous avons lancĂ© une enquĂȘte par questionnaire en ligne destinĂ©s aux Ă©tudiants pour recueillir des donnĂ©es sur leurs usages, leurs difficultĂ©s et notamment leurs perceptions de l'utilisation de la plateforme Moodle.
Mots-clés : TIC, étudiants, plateforme Moodle, dispositif, formation universitaire en ligne
A New Hybrid Cryptosystem Involving DNA,Rabin, One Time Pad and Fiestel
Information security is a crucial need in the modern world. Data security is
a real concern, and many customers and organizations need to protect their
sensitive information from unauthorized parties and attackers. In previous
years, numerous cryptographic schemes have been proposed. DNA cryptography is a
new and developing field that combines the computational and biological worlds.
DNA cryptography is intriguing due to its high storage capacity, secure data
transport, and massive parallel computing. In this paper, a new combination is
proposed that offers good security by combining DNA, the Rabin algorithm, one
time pad, and a structure inspired by Fiestel. This algorithm employs two keys.
The first key is a DNA OTP key which is used for only one secure communication
session. The second key, which combines the public and private keys, is a Rabin
key. Additionally, by using a Feistel inspired scheme and randomness provided
by DNA, the ciphertext is made harder to obtain without the private key.Comment: 11 page
Multiphase induction motor drives - a technology status review
The area of multiphase variable-speed motor drives in general and multiphase induction motor drives in particular has experienced a substantial growth since the beginning of this century. Research has been conducted worldwide and numerous interesting developments have been reported in the literature. An attempt is made to provide a detailed overview of the current state-of-the-art in this area. The elaborated aspects include advantages of multiphase induction machines, modelling of multiphase induction machines, basic vector control and direct torque control schemes and PWM control of multiphase voltage source inverters. The authors also provide a detailed survey of the control strategies for five-phase and asymmetrical six-phase induction motor drives, as well as an overview of the approaches to the design of fault tolerant strategies for post-fault drive operation, and a discussion of multiphase multi-motor drives with single inverter supply. Experimental results, collected from various multiphase induction motor drive laboratory rigs, are also included to facilitate the understanding of the drive operatio
Suppression of Stochastic Domain Wall Pinning Through Control of Gilbert Damping
Finite temperature micromagnetic simulations were used to investigate the magnetisation structure, propagation dynamics and stochastic pinning of domain walls in rare earth-doped Ni80Fe20 nanowires. We first show how the increase of the Gilbert damping, caused by the inclusion rare-earth dopants such as holmium, acts to suppress Walker breakdown phenomena. This allows domain walls to maintain consistent magnetisation structures during propagation. We then employ finite temperature simulations to probe how this affects the stochastic pinning of domain walls at notch-shaped artificial defect sites. Our results indicate that the addition of even a few percent of holmium allows domain walls to pin with consistent and well-defined magnetisation configurations, thus suppressing dynamically-induced stochastic pinning/depinning phenomena. Together, these results demonstrate a powerful, materials science-based solution to the problems of stochastic domain wall pinning in soft ferromagnetic nanowires
Développement de la microscopie interférométrique pour une meilleure analyse morphologique des couches minces et épaisses des matériaux semiconducteurs et optiques
Les techniques d'interfĂ©romĂ©trie microscopiques, basĂ©es sur le principe de l'interfĂ©rence lumineuse, ont connu un dĂ©veloppement considĂ©rable au cours des derniĂšres annĂ©es. On distingue deux familles de techniques : la microscopie Ă saut de phase (PSM) bien adaptĂ©e pour l'analyse de dĂ©fauts peu profonds Ă l'Ă©chelle nanomĂ©trique et la microscopie Ă sonde de faible cohĂ©rence (CPM) pour permettre la mesure de reliefs beaucoup plus profonds.Le but de cette Ă©tude porte sur l'amĂ©lioration des performances du montage de l'interfĂ©romĂštre microscopique en termes de sa prĂ©cision, de sa rĂ©solution, de son contrĂŽle automatique et de son utilisation dans la caractĂ©risation des couches minces et Ă©paisses utilisĂ©es dans la microĂ©lectronique et dans l'optique. En particulier, de nouveaux algorithmes de contrĂŽle, de traitement et d'analyse ont Ă©tĂ© conçus pour faciliter la caractĂ©risation des couches, et pour corriger certaines erreurs dans les mĂ©thodes PSM et CPM.Pour mieux cerner les performances et les limites du systĂšme, nous avons effectuĂ© des Ă©tudes comparatives entre nos propres mesures en PSM et en CPM et les mesures faites avec d'autres techniques (stylet, AFM, MEB et microscopie confocale) Ă travers trois applications. Nous avons montrĂ© dans la premiĂšre application que la PSM pourrait ĂȘtre utilisĂ©e pour l'Ă©talonnage quantitatif du procĂ©dĂ© de recuit laser des couches de Si-poly pour les Ă©crans plats d'une maniĂšre souple, non-destructive et beaucoup plus rapide que les mĂ©thodes classiques. Dans la deuxiĂšme application, nous avons montrĂ© que l'utilisation de la CPM pourrait contribuer Ă un prototypage rapide des ĂlĂ©ments Optiques Diffractifs (EODs) en raison de sa rapiditĂ©, de sa prĂ©cision et de sa capacitĂ© de profiler correctement des couches transparentes Ă©paisses. Dans la troisiĂšme et derniĂšre application, une nouvelle technique interfĂ©romĂ©trique non-destructive a Ă©tĂ© dĂ©veloppĂ©e pour caractĂ©riser les interfaces enterrĂ©es sous une couche transparente.Interference microscopy techniques, based on the principle of optical interference, have gone through considerable development during the last few years. Two families of techniques can be distinguished : Phase Stepping Microscopy (PSM), which is well adapted for the analysis of nanometric surface roughness, and Coherence Probe Microscopy (CPM) for the measurement of deeper micronic surface relief.The aim of this work is to improve the performance of the interference microscopy system, in terms of its precision, resolution, automatic control and use in the characterization of thin and thick layers used in microelectronics and optics. In particular, new algorithms for controlling the system and for processing and analysing the data have been developed to facilitate the characterization of layers, and to correct certain errors in the PSM and CPM measurements.To better understand the performances and limits of the system, some comparative studies were carried out between PSM and CPM measurements and those made with other techniques (stylus, SEM, AFM, and confocal microscopy) through three applications. We have shown in the first application that PSM could be used for the quantitative optimisation of the laser annealing process of poly-Si layers for flat panel displays in a flexible, non-destructive and faster manner than by using classical methods. In the second application, we have shown that the use of CPM could contribute to a new method of rapid prototyping of Diffractive Optical Elements (DOEs) due to its rapidity, precision, and ability to correctly profile thick transparent layers. In the third and last application, a new non-destructive interference technique has been developed for characterizing interfaces buried under a transparent layer
Développement de la microscopie interférométrique pour une meilleure analyse morphologique des couches minces et épaisses des matériaux semiconducteurs et optiques
Les techniques d'interfĂ©romĂ©trie microscopiques, basĂ©es sur le principe de l'interfĂ©rence lumineuse, ont connu un dĂ©veloppement considĂ©rable au cours des derniĂšres annĂ©es. On distingue deux familles de techniques : la microscopie Ă saut de phase (PSM) bien adaptĂ©e pour l'analyse de dĂ©fauts peu profonds Ă l'Ă©chelle nanomĂ©trique et la microscopie Ă sonde de faible cohĂ©rence (CPM) pour permettre la mesure de reliefs beaucoup plus profonds.Le but de cette Ă©tude porte sur l'amĂ©lioration des performances du montage de l'interfĂ©romĂštre microscopique en termes de sa prĂ©cision, de sa rĂ©solution, de son contrĂŽle automatique et de son utilisation dans la caractĂ©risation des couches minces et Ă©paisses utilisĂ©es dans la microĂ©lectronique et dans l'optique. En particulier, de nouveaux algorithmes de contrĂŽle, de traitement et d'analyse ont Ă©tĂ© conçus pour faciliter la caractĂ©risation des couches, et pour corriger certaines erreurs dans les mĂ©thodes PSM et CPM.Pour mieux cerner les performances et les limites du systĂšme, nous avons effectuĂ© des Ă©tudes comparatives entre nos propres mesures en PSM et en CPM et les mesures faites avec d'autres techniques (stylet, AFM, MEB et microscopie confocale) Ă travers trois applications. Nous avons montrĂ© dans la premiĂšre application que la PSM pourrait ĂȘtre utilisĂ©e pour l'Ă©talonnage quantitatif du procĂ©dĂ© de recuit laser des couches de Si-poly pour les Ă©crans plats d'une maniĂšre souple, non-destructive et beaucoup plus rapide que les mĂ©thodes classiques. Dans la deuxiĂšme application, nous avons montrĂ© que l'utilisation de la CPM pourrait contribuer Ă un prototypage rapide des ĂlĂ©ments Optiques Diffractifs (EODs) en raison de sa rapiditĂ©, de sa prĂ©cision et de sa capacitĂ© de profiler correctement des couches transparentes Ă©paisses. Dans la troisiĂšme et derniĂšre application, une nouvelle technique interfĂ©romĂ©trique non-destructive a Ă©tĂ© dĂ©veloppĂ©e pour caractĂ©riser les interfaces enterrĂ©es sous une couche transparente.Interference microscopy techniques, based on the principle of optical interference, have gone through considerable development during the last few years. Two families of techniques can be distinguished : Phase Stepping Microscopy (PSM), which is well adapted for the analysis of nanometric surface roughness, and Coherence Probe Microscopy (CPM) for the measurement of deeper micronic surface relief.The aim of this work is to improve the performance of the interference microscopy system, in terms of its precision, resolution, automatic control and use in the characterization of thin and thick layers used in microelectronics and optics. In particular, new algorithms for controlling the system and for processing and analysing the data have been developed to facilitate the characterization of layers, and to correct certain errors in the PSM and CPM measurements.To better understand the performances and limits of the system, some comparative studies were carried out between PSM and CPM measurements and those made with other techniques (stylus, SEM, AFM, and confocal microscopy) through three applications. We have shown in the first application that PSM could be used for the quantitative optimisation of the laser annealing process of poly-Si layers for flat panel displays in a flexible, non-destructive and faster manner than by using classical methods. In the second application, we have shown that the use of CPM could contribute to a new method of rapid prototyping of Diffractive Optical Elements (DOEs) due to its rapidity, precision, and ability to correctly profile thick transparent layers. In the third and last application, a new non-destructive interference technique has been developed for characterizing interfaces buried under a transparent layer.STRASBOURG-Sc. et Techniques (674822102) / SudocSudocFranceF