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[en] Today's world is flooded with vast amounts of digital information coming from innumerable sources. Moreover, it seems clear that this trend will only intensify in the future. Industry, society and remarkably science are not indifferent to this fact. On the contrary, they are struggling to get the most out of this data, which means that they need to capture, transfer, store and process it in a timely and efficient manner, using a wide range of computational resources. And this task is not always simple. A very representative example of the challenges posed by the management and processing of large quantities of data is that of the Large Hadron Collider experiments, which handle tens of petabytes of physics information every year. Based on the experience of one of these collaborations, we have studied the main issues involved in the management of huge volumes of data and in the completion of sizeable workflows that consume it. In this context, we have developed a general-purpose architecture for the scheduling and execution of workflows with heavy data requirements: the Task Queue. This new system builds on the late-binding overlay model, which has helped experiments to successfully overcome the problems associated to the heterogeneity and complexity of large computational grids. Our proposal introduces several enhancements to the existing systems. The execution agents of the Task Queue architecture share a Distributed Hash Table (DHT) and perform job matching and assignment cooperatively. In this way, scalability problems of centralized matching algorithms are avoided and workflow execution times are improved. Scalability makes fine-grained micro-scheduling possible and enables new functionalities, like the implementation of a distributed data cache on the execution nodes and the integration of data location information in the scheduling decisions...(Author)
[en] Routine evaluation in X-ray photoelectron spectrometry comprises the standard evaluation steps 1) energy calibration 2) sample charging 3) spectrum processing 4) binding energy 5) layer thickness determination 6) quantitative analytics. This work shows the foundations and describes the development of computer codes for an on-site evaluation of measurement data with the help of an EPSON HX-20 computer. (Author, translated by G.Q.)
[en] The subject of this thesis is the study of the propagation of femtosecond laser pulses in transparent solids. The short duration of these pulses (a few 10"-"1"5 to a few 10"-"1"3 s) supplies high light intensities with modest energies. When they traverse a transparent medium, theses strong laser intensities induce important nonlinearities which affect the pulse propagation. These nonlinearities can lead to a self-guided propagation with high intensities on long distances. This propagation is called laser filamentation. By focusing pulse of 2 mJ, 160 fs and with 800 nm as central wavelength, I have induced a laser filamentation in a 2 cm thick fused silica sample. The experimental study of this nonlinear propagation is the first precise and complete characterization of a filament in a transparent solid medium. Comparison between experimental and numerical results given by numerical code permits to show that laser filamentation can take place in solid, media in the same way as in gases. Equilibrium between self-focusing due to Kerr effect and defocusing by the plasma is the origin of filamentation. Defocusing limits the laser intensity and avoids sample damaging. This close relation between propagation and damaging led me to consider more strongly focused pulses propagation inside fused silica. This type of propagation leads to high electronic densities that induce irreversible damages. Comparison between numerical and experimental results permits to precise the conditions for damages appearance while giving experimentally inaccessible physical quantities. I have also observed in fused silica a new type of modifications with a strong birefringence. As an application I have made optical elements like waveguides and diffraction gratings. (author)
[fr]L'objet de cette these est l'etude de la propagation des impulsions femtosecondes dans les solides transparents. La duree de ces impulsions tres courtes est typiquement de l'ordre de quelques 10"-"1"5 a quelques 10"-"1"3 s. Elles peuvent fournir de hautes intensites lumineuses pour des energies modestes. Par exemple, une impulsion de 1 μJ et 100 fs focalisee sur une tache de rayon 1 μm impose au milieu une intensite de 10"1"5 W/cm"2. Lorsqu'elles traversent un milieu transparent, ces fortes intensites laser induisent des non-linearites importantes qui affectent la propagation de l'impulsion. Ces non-linearites donnent lieu a des effets spectaculaires. Par exemple, depuis 1995, plusieurs groupes ont etudie la propagation auto-guidee d'impulsions femtosecondes dans l'atmosphere. La propagation d'une impulsion intense dans un milieu fait intervenir entre autre deux effets non-lineaires qui jouent deux roles opposes. L'effet Kerr optique tend a focaliser le faisceau alors que l'ionisation du milieu le defocalise. Schematiquement, on peut dire que si ces deux phenomenes se contrebalancent ils peuvent conduire a une propagation des impulsions laser avec de hautes intensites sur de longues distances. Ce regime de propagation est appele auto-guidage femtoseconde
[en] There are illogical and irrational rules in numbers writing and pronunciation in almost of languages. A part of the aim is to show the electronic applications possibility of logical and systematic rules which are proposed by Raoelina Andriambololona to write and pronounce numbers; we had studied and created the arithmetic operations representation corresponding in binary basis and in hexadecimal basis. The brand new found concept corresponds as well as the method which uses the matrix product calculation, in according with the writing and the pronunciation of numbers. It was shown how to concept the arithmetic operators in digital electronics; and we proposed and assumed to make headway and to do amelioration for technical conception of calculator and arithmetic unite those are at the basic function of all computers and almost domestic sophisticated machine. The left hand side- right hand side and increasing order writing of number is exploited to build a new computer programming for a scientific calculator.
[fr]Il y a des regles illogiques et non rationnelles pour l'ecriture et la prononciation des nombres dans presque toutes les langues. Pour plus de precision, Raoelina Andriambololona a propose de nouvelles regles qui peuvent etre appliquees dans toutes les langues. L'utilisation du calcul matriciel en arithmetique est parfaitement en accord avec ces regles. Ce travail consiste a etudier un nouveau concept plus logique puis a trouver toutes les consequences et les possibilites de ses applications. En electronique, on a etudie la representation, dans la base binaire et dans la base hexadecimale, des operations arithmetiques. De nouvelles techniques pour la conception electronique des operateurs arithmetiques sont inventees ; et nous avons propose d'ameliorer, en utilisant la numeration Malagasy, les techniques de conception des calculateurs et de l'Unite Arithmetique qui demeurent desormais dans tous les micro-ordinateurs et dans les appareils modernes ou sophistiquees de nos jours. On a aussi trouve des algorithmes correspondants en informatique ; et on a programme une machine calculatrice scientifique.
[en] In this study, the response of CANDU-6 nuclear reactor to several transients are investigated. The simulation of the system is performed by using RELAP5 thermalhydraulic system code. AECL performes the transient simulations of CANDU reactor by using the FIREBIRD code, developed by AECL for thermal hydraulic analysis of CANDU. All analysis for LOCA and ECCS effectiveness were done by using the FIREBIRD code. The investigations concerning the RELAP5 analysis of CANDU system are too few. Better normal operating conditions are achieved, the effect of pipe interconnecting the outlet headers in a loop is observed. It is found that, with the reactor outlet headers interconnected, the system is stable to perturbations but would exhibit divergent pressure, quality and flow oscillations if the interconnection is removed and if the quality at the reactor outlet header region is greater than 1-2% but less than 8%, specific large (100% of flow area) and small (10% of flow area) breaks in both inlet and outlet headers and in the pump suction are analysed. Results indicate that, l00% break in the inlet header has more probability of fuel failure than the same size break in the outlet header. The worst break location is found to be the pump suction with a break size of 100%. Higher void fractions, higher outlet header quality and heat temperatures are observed in the large break transients than that of small break transients. For small break transients, the break location in the inlet header results higher void fraction, outlet header quality and sheath temperatures than that of outlet header break transients. Emergency core cooling system (ECCS) is found to be effective for the cases analysed. Initiating trip parameters and time for scram and ECCS injection is also investigated
[en] The development of a system that renders possible a better man-computer interaction is studied for application in IBM 1620-mod. 2 of 40K computer used in IEA-SP (Brazil)
[pt]O desenvolvimento de um sistema capaz de tornar possivel uma melhor interacao homem-computador foi estudada para posterior aplicacao no computador IBM 1620-mod 2 de 40K utilizado pelos pesquisadores do IEA-SP, Brasil
[en] In particle accelerators, there are numerous beam instabilities. There are essentially space charge effects, chromatic effects and Beam Breakup instability. This instability results from progressively larger electromagnetic fields excited by the beam in subsequent sections of the accelerator, which affect the beam motion. This effect becomes more pronounced as the beam goes further down the accelerator. This instability put a limit on the beam intensity and drastically reduce the beam quality. We have studied theoretically the different processes of this phenomenon for an induction linac, and we have found the amplification laws for different beam conditions. From these results, we have developed a code of beam transport, and made some numerical studies on the Beam Breakup instability in the case of PlVAIR accelerator (8 cells, 8 MeV, 3,5 kA, 60 ns). We have evaluated the influence of the different parameters of the beam and of the accelerator, in particular the transverse impedance of the cells. Some experiments achieved on PlVAIR accelerator have allowed to observe this phenomenon and to reconcile with code predictions. We have determined the transverse impedance of the cells and extrapolated these results to AlRIX accelerator accelerator (64 cells, 8 MeV, 3,5 kA, 60 ns). (author)
[fr]Dans les accelerateurs de particules, il existe de nombreuses instabilites du faisceau. Elles sont dues principalement aux effets de charge d'espace, aux effets chromatiques, et a l'effet connu dans la litterature Anglo-saxonne sous le nom de 'Beam Breakup'. Cette instabilite provient de l'excitation par le faisceau de champs electromagnetiques dans les differentes cavites acceleratrices, qui impriment alors un mouvement au faisceau. Ce phenomene augmente au fur et mesure que le faisceau se propage dans l'accelerateur. Cette instabilite fixe la valeur maximale du courant pouvant etre transporte et reduit de facon importante la qualite du faisceau. Apres avoir etudie de maniere theorique, les differents processus qui peuvent developper cette instabilite dans un accelerateur a induction, nous avons etabli des lois d'evolution du phenomene, pour des conditions initiales du faisceau differentes ainsi que pour des conditions de transport particulieres. A partir de ces resultats, nous avons developpe un code de transport du faisceau et effectue une etude numerique de l'instabilite de Beam Breakup pour l'accelerateur a induction PIVAIR (8 cellules a induction, 8 MeV, 3,5 kA, 60 ns). Nous avons evalue l'influence des differents parametres du faisceau et de l'accelerateur, en particulier de l'impedance transverse des cellules a induction. Une serie d'experiences menee sur l'accelerateur PlVAIR a permis d'observer ce phenomene et de recaler le code. Nous avons determine l'impedance transverse des cellules a induction et extrapole les resultats a l'accelerateur AIRIX (64 cellules a induction, 20 MeV, 3,5 kA, 60 ns).
[en] A macro-generator is a translator which is able to interpret and translate a programme written in a macro-language. After a first part presenting the main notions and proposing a brief description of the TAS-86 language, the second part of this research thesis reports the development of the macro-generator language, and notably presents the additional functionalities provided by the macro generator. The development is illustrated by logical flowcharts and programming listings