963 resultados para DC-bus voltages


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We report the results of the growth of Cu-Sn-S ternary chalcogenide compounds by sulfurization of dc magnetron sputtered metallic precursors. Tetragonal Cu2SnS3 forms for a maximum sulfurization temperature of 350 ºC. Cubic Cu2SnS3 is obtained at sulfurization temperatures above 400 ºC. These results are supported by XRD analysis and Raman spectroscopy measurements. The latter analysis shows peaks at 336 cm-1, 351 cm-1 for tetragonal Cu2SnS3, and 303 cm-1, 355 cm-1 for cubic Cu2SnS3. Optical analysis shows that this phase change lowers the band gap from 1.35 eV to 0.98 eV. At higher sulfurization temperatures increased loss of Sn is expected in the sulphide form. As a consequence, higher Cu content ternary compounds like Cu3SnS4 grow. In these conditions, XRD and Raman analysis only detected orthorhombic (Pmn21) phase (petrukite). This compound has Raman peaks at 318 cm-1, 348 cm-1 and 295 cm-1. For a sulfurization temperature of 450 ºC the samples present a multi-phase structure mainly composed by cubic Cu2SnS3 and orthorhombic (Pmn21) Cu3SnS4. For higher temperatures, the samples are single phase and constituted by orthorhombic (Pmn21) Cu3SnS4. Transmittance and reflectance measurements were used to estimate a band gap of 1.60 eV. For comparison we also include the results for Cu2ZnSnS4 obtained using similar growth conditions.

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The use of multicores is becoming widespread inthe field of embedded systems, many of which have real-time requirements. Hence, ensuring that real-time applications meet their timing constraints is a pre-requisite before deploying them on these systems. This necessitates the consideration of the impact of the contention due to shared lowlevel hardware resources like the front-side bus (FSB) on the Worst-CaseExecution Time (WCET) of the tasks. Towards this aim, this paper proposes a method to determine an upper bound on the number of bus requests that tasks executing on a core can generate in a given time interval. We show that our method yields tighter upper bounds in comparison with the state of-the-art. We then apply our method to compute the extra contention delay incurred by tasks, when they are co-scheduled on different cores and access the shared main memory, using a shared bus, access to which is granted using a round-robin arbitration (RR) protocol.

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The usage of COTS-based multicores is becoming widespread in the field of embedded systems. Providing realtime guarantees at design-time is a pre-requisite to deploy real-time systems on these multicores. This necessitates the consideration of the impact of the contention due to shared low-level hardware resources on the Worst-Case Execution Time (WCET) of the tasks. As a step towards this aim, this paper first identifies the different factors that make the WCET analysis a challenging problem in a typical COTS-based multicore system. Then, we propose and prove, a mathematically correct method to determine tight upper bounds on the WCET of the tasks, when they are co-scheduled on different cores.

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The current industry trend is towards using Commercially available Off-The-Shelf (COTS) based multicores for developing real time embedded systems, as opposed to the usage of custom-made hardware. In typical implementation of such COTS-based multicores, multiple cores access the main memory via a shared bus. This often leads to contention on this shared channel, which results in an increase of the response time of the tasks. Analyzing this increased response time, considering the contention on the shared bus, is challenging on COTS-based systems mainly because bus arbitration protocols are often undocumented and the exact instants at which the shared bus is accessed by tasks are not explicitly controlled by the operating system scheduler; they are instead a result of cache misses. This paper makes three contributions towards analyzing tasks scheduled on COTS-based multicores. Firstly, we describe a method to model the memory access patterns of a task. Secondly, we apply this model to analyze the worst case response time for a set of tasks. Although the required parameters to obtain the request profile can be obtained by static analysis, we provide an alternative method to experimentally obtain them by using performance monitoring counters (PMCs). We also compare our work against an existing approach and show that our approach outperforms it by providing tighter upper-bound on the number of bus requests generated by a task.

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Contention on the memory bus in COTS based multicore systems is becoming a major determining factor of the execution time of a task. Analyzing this extra execution time is non-trivial because (i) bus arbitration protocols in such systems are often undocumented and (ii) the times when the memory bus is requested to be used are not explicitly controlled by the operating system scheduler; they are instead a result of cache misses. We present a method for finding an upper bound on the extra execution time of a task due to contention on the memory bus in COTS based multicore systems. This method makes no assumptions on the bus arbitration protocol (other than assuming that it is work-conserving).

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Dissertação para a obtenção do grau de Mestre em Engenharia Electrotécnica Ramo de Energia

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The CD209 gene family that encodes C-type lectins in primates includes CD209 (DC-SIGN), CD209L (L-SIGN) and CD209L2. Understanding the evolution of these genes can help understand the duplication events generating this family, the process leading to the repeated neck region and identify protein domains under selective pressure. We compiled sequences from 14 primates representing 40 million years of evolution and from three non-primate mammal species. Phylogenetic analyses used Bayesian inference, and nucleotide substitutional patterns were assessed by codon-based maximum likelihood. Analyses suggest that CD209 genes emerged from a first duplication event in the common ancestor of anthropoids, yielding CD209L2 and an ancestral CD209 gene, which, in turn, duplicated in the common Old World primate ancestor, giving rise to CD209L and CD209. K(A)/K(S) values averaged over the entire tree were 0.43 (CD209), 0.52 (CD209L) and 0.35 (CD209L2), consistent with overall signatures of purifying selection. We also assessed the Toll-like receptor (TLR) gene family, which shares with CD209 genes a common profile of evolutionary constraint. The general feature of purifying selection of CD209 genes, despite an apparent redundancy (gene absence and gene loss), may reflect the need to faithfully recognize a multiplicity of pathogen motifs, commensals and a number of self-antigens

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Contient : « Le livre des parties d'Oultre mer, lequel fu fait, ordonné et compilé par honorable et vaillant seigneur Jehan de Mandeville... Escript (fol. 62) par moy, Ogier de Caumont, en la cité de Liege, et finy le penultieme jour de juillet l'an mil CCC IIIIxx??? et XVI. » Cf. R. Röhricht, Bibliotheca geographica Palestinae, p. 79 ; On lit : « Hunc librum acquisivit monasterio Sancti Victoris prope Parisius frater Johannes Lamasse, dum esset prior ejusdem ecclesie. Scriptum anno Domini 1424 » ; Prière à la Vierge ; « Dit de la rose », pièce en l'honneur de la Vierge ; Les peines de l'enfer ; « Scriptum quoddam super degradatione et combustione quorumdam fratrum ordinis Predicatorum, qui... opinionem suam ab ecclesia damnata de conceptione purissime Virginis matris Domini Jhesu deffendere nitebantur... Actum anno Domini millesimo quingentesimo nono. » Cf. Du Boulay, Historia Universitatis Parisiensis, t. VI, p. 45 ; Pater Noster et Ave Maria, en vers ; Vers sur le plaisir de boire. « Ad primum morsum, nisi potavero mort sum... » (15 vers) ; « Statutum sacre facultatis Theologie studii Parisiensis super materia conceptionis immaculate gloriosissime Virginis... » (1497) ; Paraphrase, en vers français, de l'Ave maris stella ; « Clericus sic ethimologizatur : Per c intelligitur quod sit clarus... » ; « Almalarius (sic), qui loquitur de duobus ebdomadis passionis Christi. Due ebdomade passionis Christi significant duo tempora ante legem et sub lege... » ; Explications, en latin, du Pater et du Credo. « Elegit Dominus Deus noster Jhesus Christus septem apostolos... » ; « Tabula fidei christiane. Septem virtutes principales : fides, spes... » ; Notes de comput. « Ad habendum ciclum solarem, secundum Gallandum, sive litteram dominicalem... » ; Prière à la Vierge ; « La deputaison » ou « le mireur du corps et de l'ame. Une grant vision est en ce livre escripte... » ; Prières à la Vierge ; I ; II ; III ; Note relative à « Jehan Le Mire, jadis trésorier des guerres » (1339) ; La maison de sapience ; Poème moral sur la mort du Christ ; Vers latins, en l'honneur de S. Jean-Baptiste ; « Missa pro evitanda mortalitate, quam dominus papa Clemens sextus constituit et fecit... » ; « Le Testament maistre Jehan de Meun. » Cf. Histoire littéraire, t. XXVIII (1880), p. 416 (art. de P. Paris) ; Roman de Fauvel, par Gervais Du Bus. Cf. Histoire littéraire, t. XXXII (1898), p. 108 (art. de M. G. Paris) ; Vers latins contre les femmes ; Autre pièce contre les femmes ; Autre pièce sur les femmes. « Se j'avoye une fame qui ne me mentist point... » ; Prière. « Doulx Diex, qui es sans fin et sans initium... » ; « Les heures de la Croiz [en vers], ausquellez le pape Jehan XXII donna i an ex xl jours de vray pardon à quelconque persone, qui par devocion dira ceste office du mistère de la Passion Jhesu Crist » ; Prière à la Vierge

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Contient : « Liber Fortunæ, » poème religieux et moral, sous forme d'un songe, daté de 1345 ; « Testament maistre JEHAN DE MEUN, que on appelle le livre du Père, et du Filz et du saint Esperit » ; Grand codicille de JEAN DE MEUNG ; Passion de Jésus-Christ, en prose. « Qui de Dieu est de Dieu parole et garde ses euvres... » ; « Estrille Fauvel ; » en deux livres (16 déc. 1314), par GERVAIS DU Bus. — Cf. G. Paris, dans Histoire littéraire, XXXII, 136