Global ETD Search

31	Higher Radix Floating-Point Representations for FPGA-Based Arithmetic Catanzaro, Bryan Christopher 22 April 2005 (has links) (PDF) Field Programmable Gate Arrays (FPGAs) are increasingly being used for high-throughput floating-point computation. It is forecasted that by 2009, FPGAs will provide an order of magnitude greater sustained floating-point throughput than conventional processors. FPGA implementations of floating-point operators have historically been designed to use binary floating-point representations, as do general purpose processors. Binary representations were chosen as the standard over three decades ago because they provide maximal numerical accuracy per bit of floating-point data. However, the unique nature of FPGA-based computation makes numerical accuracy per unit of FPGA resources a more important measure of the usefulness of a given floating-point representation. From this viewpoint, higher radix floating-point representations are well suited to FPGA-based computations, especially high precision calculations which require the support of denormalized numbers. This work shows that higher radix representations lead to more efficient use of FPGA resources. For example, a hexadecimal floating-point adder provides a 30% lower Area-Time product than its binary counterpart, and a hexadecimal floating-point multiplier has a 13% lower Area-Time product than its binary counterpart. This savings occurs while still delivering equal worst-case and better average-case numerical accuracy. This work presents a family of higher radix floating-point representations that are designed specifically to interoperate with standard IEEE floating-point, allowing the creation of floating-point datapaths which operate on standard binary floating-point data, yet use higher radix representations internally. Such datapaths provide higher performance by any measure: they are more accurate numerically, consume less FPGA resources and have shorter latencies. When taking into consideration the unique nature of FPGA-based computing systems, this work shows that binary floating-point representations are not optimal for most FPGA-based arithmetic computations. Higher radix representations can therefore be a useful tool for building efficient custom floating-point datapaths on FPGAs. FPGA computer arithmetic floating-point fixed-point floating fixed point radix rounding add multiply numerical accuracy throughput latency binary hexadecimal denormalized Electrical and Computer Engineering
32	An index theorem for operators with horn singularities Lapp, Frank 05 November 2013 (has links) Die abgeschlossenen Erweiterungen der sogenannten geometrischen Operatoren (Spin-Dirac, Gauß-Bonnet und Signatur-Operator) auf Mannigfaltigkeiten mit metrischen Hörnern sind Fredholm-Operatoren und ihr Index wurde von Matthias Lesch, Norbert Peyerimhoff und Jochen Brüning berechnet. Es wurde gezeigt, dass die Einschränkungen dieser drei Operatoren auf eine punktierte Umgebung des singulären Punkts unitär äquivalent zu irregulär singulären Operator-wertigen Differentialoperatoren erster Ordnung sind. Die Lösungsoperatoren der dazugehörigen Differentialgleichungen definierten eine Parametrix, mit deren Hilfe die Fredholmeigenschaft bewiesen wurde. In der vorliegenden Doktorarbeit wird eine Klasse von irregulären singulären Differentialoperatoren erster Ordnung, genannt Horn-Operatoren, eingeführt, die die obigen Beispiele verallgemeinern. Es wird bewiesen, dass ein elliptischer Differentialoperator erster Ordnung, dessen Einschränkung auf eine punktierte Umgebung des singulären Punkts unitär äquivalent zu einem Horn-Operator ist, Fredholm ist, und sein Index wird berechnet. Schließlich wird dieser abstrakte Index-Satz auf geometrische Operatoren auf Mannigfaltigkeiten mit "multiply warped product"-Singularitäten angewendet, welche eine wesentliche Verallgemeinerung der metrischen Hörner darstellen. / The closed extensions of geometric operators (Spin-Dirac, Gauss-Bonnet and Signature operator) on a manifold with metric horns are Fredholm operators, and their indices were computed by Matthias Lesch, Norbert Peyerimhoff and Jochen Brüning. It was shown that the restrictions of all three operators to a punctured neighbourhood of the singular point are unitary equivalent to a class of irregular singular operator-valued differential operators of first order. The solution operators of the corresponding differential equations defined a parametrix which was applied to prove the Fredholm property. In this thesis a class of irregular singular differential operators of first order - called horn operators - is introduced that extends the examples mentioned above. It is proved that an elliptic differential operator of first order whose restriction to the neighbourhood of the singular point is unitary equivalent to a horn operator is Fredholm and its index is computed. Finally, this abstract index theorem is applied to compute the indices of geometric operators on manifolds with multiply warped product singularities that extend the notion of metric horns considerably. Fredhol-Index metrisches Horn Spin-Dirac Gauß-Bonnet Signatur mehrfach gewarpte Produkte singuläre Mannigfaltigkeit Atiyah-Singer Fredholm index metric horn Spin Dirac Gauss-Bonnet Signature multiply warped products singular manifold Atiyah-Singer 510 Mathematik 27 Mathematik SK 620 ddc:510
33	Estimation multi-robuste efficace en présence de données influentes Michal, Victoire 08 1900 (has links) No description available. Robustesse Imputation multi-robuste Biais conditionnel Inférence basée sur le plan de sondage Unités influentes Non-réponse Robustness Multiply robust imputation Conditional bias Design-based inference Influential units Item nonresponse
34	Strength Properties of Paper produced from Softwood Kraft Pulp : Pulp Mixture, Reinforcement and Sheet Stratification Karlsson, Hanna January 2010 (has links) For paper producers, an understanding of the development of strength properties in the paper is of uttermost importance. Strong papers are important operators both in the traditional paper industry as well as in new fields of application, such as fibre-based packaging, furniture and light-weight building material. In the work reported in this thesis, three approaches to increasing paper strength were addressed: mixing different pulps, multilayering and reinforcement with man-made fibres. In specific: The effects of mixing Swedish softwood kraft pulp with southern pine or with abaca (Musa Textilis) were investigated. Handsheets of a softwood kraft pulp with the addition of abaca fibres were made in a conventional sheet former. It was seen that the addition of abaca fibres increased the tearing resistance, fracture toughness, folding endurance and air permeance. Tensile strength, tensile stiffness and tensile energy absorption, however, decreased somewhat. Still it was possible to add up to about 60% abaca without any great loss in tensile strength. As an example, with the addition of 30% abaca, the tear index was increased by 36%, while the tensile index was decreased by 8%. To study the effect of stratification, a handsheet former for the production of stratified sheets, the LB Multilayer Handsheet Former was evaluated. The advantage of this sheet former is that it forms a stratified sheet at low consistency giving a good ply bond. It was shown to produce sheets with good formation and the uniformity, evaluated as the variation of paper properties, is retained at a fairly constant level when the number of layers in the stratified sheets is increased. The uniformity of the sheets produced in the LB Multilayer Handsheet Former is generally at the same level as of those produced in conventional sheet formers. The effects of placing southern pine and abaca in separate layers, rather than mixing them homogeneously with softwood pulp were studied. Homogeneous and stratified sheets composed of softwood and southern pine or softwood and abaca were produced in the LB Multilayer Handsheet Former. It was found that by stratifying a sheet, so that a pulp with a high tear index and a pulp with a high tensile index are placed in separate layers, it was possible to increase the tear index by approximately 25%, while the tensile index was decreased by 10-20%. Further, by mixing a pulp with less conformable fibres and no fines with a pulp with more flexible fibres and fines, a synergy in tensile strength (greater strength than that predicted by linear mass fraction additivity) was obtained. The effects of stratifying sheets composed of softwood and abaca were compared to the effects of refining the softwood pulp. Homogeneous and stratified sheets composed of softwood with three different dewatering resistances and abaca were also produced in the LB Multilayer Handsheet Former. It was found that by stratifying the sheets the tear index was retained while the tensile index was increased by the refining. The effects of reinforcing softwood pulp of different dewatering resistances with man-made fibres with low bonding ability were also investigated. Man-made fibres (i.e. regenerated cellulose, polyester and glass fibres) were added in the amounts 1, 3, or 5 wt% to softwood pulp of three different dewatering resistances. It was found that with refining of a softwood pulp and subsequent addition of long fibres with low bonding ability the tensile-tear relationship can be shifted towards higher strength values. The bonding ability of the man-made fibres was evaluated by pull-out tests and the results indicated that, in relation to the fibre strength, regenerated cellulose (lyocell) was most firmly attached to the softwood network while the glass fibres were most loosely attached. paper strength tensile strength tearing resistance folding endurance fracture toughness handsheet former stratify multilayer multiply reinforcement refining beating abaca glass fibre polyester lyocell softwood bond strength Cellulose and paper engineering Cellulosa- och pappersteknik
35	Rozdělení extrémních hodnot a jejich aplikace / Extreme Value Distributions with Applications Fusek, Michal January 2013 (has links) The thesis is focused on extreme value distributions and their applications. Firstly, basics of the extreme value theory for one-dimensional observations are summarized. Using the limit theorem for distribution of maximum, three extreme value distributions (Gumbel, Fréchet, Weibull) are introduced and their domains of attraction are described. Two models for parametric functions estimation based on the generalized extreme value distribution (block maxima model) and the generalized Pareto distribution (threshold model) are introduced. Parameters estimates of these distributions are derived using the method of maximum likelihood and the probability weighted moment method. Described methods are used for analysis of the rainfall data in the Brno Region. Further attention is paid to Gumbel class of distributions, which is frequently used in practice. Methods for statistical inference of multiply left-censored samples from exponential and Weibull distribution considering the type I censoring are developed and subsequently used in the analysis of synthetic musk compounds concentrations. The last part of the thesis deals with the extreme value theory for two-dimensional observations. Demonstrational software for the extreme value distributions was developed as a part of this thesis.
36	Epidemic models and inference for the transmission of hospital pathogens Forrester, Marie Leanne January 2006 (has links) The primary objective of this dissertation is to utilise, adapt and extend current stochastic models and statistical inference techniques to describe the transmission of nosocomial pathogens, i.e. hospital-acquired pathogens, and multiply-resistant organisms within the hospital setting. The emergence of higher levels of antibiotic resistance is threatening the long term viability of current treatment options and placing greater emphasis on the use of infection control procedures. The relative importance and value of various infection control practices is often debated and there is a lack of quantitative evidence concerning their effectiveness. The methods developed in this dissertation are applied to data of methicillin-resistant Staphylococcus aureus occurrence in intensive care units to quantify the effectiveness of infection control procedures. Analysis of infectious disease or carriage data is complicated by dependencies within the data and partial observation of the transmission process. Dependencies within the data are inherent because the risk of colonisation depends on the number of other colonised individuals. The colonisation times, chain and duration are often not visible to the human eye making only partial observation of the transmission process possible. Within a hospital setting, routine surveillance monitoring permits knowledge of interval-censored colonisation times. However, consideration needs to be given to the possibility of false negative outcomes when relying on observations from routine surveillance monitoring. SI (Susceptible, Infected) models are commonly used to describe community epidemic processes and allow for any inherent dependencies. Statistical inference techniques, such as the expectation-maximisation (EM) algorithm and Markov chain Monte Carlo (MCMC) can be used to estimate the model parameters when only partial observation of the epidemic process is possible. These methods appear well suited for the analysis of hospital infectious disease data but need to be adapted for short patient stays through migration. This thesis focuses on the use of Bayesian statistics to explore the posterior distributions of the unknown parameters. MCMC techniques are introduced to overcome analytical intractability caused by partial observation of the epidemic process. Statistical issues such as model adequacy and MCMC convergence assessment are discussed throughout the thesis. The new methodology allows the quantification of the relative importance of different transmission routes and the benefits of hospital practices, in terms of changed transmission rates. Evidence-based decisions can therefore be made on the impact of infection control procedures which is otherwise difficult on the basis of clinical studies alone. The methods are applied to data describing the occurrence of methicillin-resistant Staphylococcus aureus within intensive care units in hospitals in Brisbane and London Bayesian inference Markov chain Monte Carlo reversible jump transdimensional stochastic epidemic model susceptible-infected model SI model generalised linear model hospital epidemiology infectious diseases infection control nosocomial infection hospital-acquired infection multiply-resistant organisms antibioticresistant bacteria Staphylococcus aureus sensitivity detectability
37	Zabezpečení vysokorychlostních komunikačních systémů / Protection of highspeed communication systems Smékal, David January 2015 (has links) The diploma thesis deals with 128–bit AES data encryption and its implementation in FPGA network card using VHDL programming language. The theoretical part explains AES encryption and decryption, its individual steps and operating modes. Further was described the VHDL programming language, development environment Vivado, FPGA network card Combo–80G and configurable framework NetCOPE. The practical part is the implementation of AES–128 in VHDL. A simulation was used to eliminate errors, then the synthesis was performed. These steps were made using Vivado software. Last step of practical part was testing of synthesized firmware on COMBO–80G card. Total of 4 projects were implemented in FPGA card. Two of them were AES encryption and decryption with ECB mode and another two describe the encryption and decryption with CBC mode.
38	Student-led cell group ministry as 'n model vir jeugbediening / Student-led cell group ministry as a model for youth ministry Nel, Adriaan Marthinus 06 1900 (has links) Text in Afrikaans / Die een biljoen tieners wereldwyd (Borgman 1997:3) is nie meer dieselfde as 'n paar jaar gelede nie, maar raak daagliks moeiliker om te bereik. 'n Generasie wat wereldburgerskap ontvang het en deur die Televisie vermaak en die Media beinvloed word. Jongmense, skrikkerig vir "commitment", nie anti-godsdiens nie, maar soekend om te bepaal watter een die regte God is. Die kerk het vir die Millennium generasie tieners "boring" geraak want weekliks word hulle vermaak. Die uitdaging vir jeugbedienings lê daarin dat hierdie moderne tiener uit hulle geestelike verveeldheid uitgehelp sal word sodat hulle iets kan begin doen met dit wat hulle vir jare al weet. Die Tienerleier selgroep model is gerig op die verstaan van Millennium tieners en hulle geestelik te help groei. Met die oop steel in gedagte word elke tiener wat Jesus Christus as 'n werklikheid ontdek het gemotiveer om hierdie werklikheid met 'n ander tiener te gaan deel. / The one billion teenagers in the world (Borgman 1997:3) today are very different than a few years ago. The process to reach them with the Gospel is recently more difficult than ever. As citizens of the Global village they enjoy the entertainment on television and dress in the way the media proclaims. Modern youth are scared of commitment, not really anti-religion but searching for the true God. The youth of today look to the church to show them something, no, SOMEONE but instead the church became boring to them. We need to help them step out of their own boredom and do something with what they know (Hutchcraft 1996:168). With the focus on spiritual growth, and the vacant chair to remind them of their lost friends, the student-led cell group model can be one of the most effective strategies for reaching and serving the teenager of the next century. / Philosophy, Practical & Systematic Theology / M. Diac. (Jeugwerk) Jeugfilosofie Na binne-gerigte jeugbediening Generasies Millennium tiener Tienerleier selgroepe Selgroep byeenkoms Verdeling Vier dodelike dekades Selleier opleiding Bybelse fundering Geloofsgroei Uitreiking Oikos Vermaak Administrasie Volwasse mentors Youth philosophy Inside focus Generations Millennial teenager Student-Led cell groups Cell group meeting Multiply a group Four deadly decades Celleader training Bible foundation Growth in faith Outreach Oikos Entertainment Administration Adult mentors 259.23 Generation X Church group work with teenagers Church work with teenagers Group ministry Church group work with youth
39	Student-led cell group ministry as 'n model vir jeugbediening / Student-led cell group ministry as a model for youth ministry Nel, Adriaan Marthinus 06 1900 (has links) Text in Afrikaans / Die een biljoen tieners wereldwyd (Borgman 1997:3) is nie meer dieselfde as 'n paar jaar gelede nie, maar raak daagliks moeiliker om te bereik. 'n Generasie wat wereldburgerskap ontvang het en deur die Televisie vermaak en die Media beinvloed word. Jongmense, skrikkerig vir "commitment", nie anti-godsdiens nie, maar soekend om te bepaal watter een die regte God is. Die kerk het vir die Millennium generasie tieners "boring" geraak want weekliks word hulle vermaak. Die uitdaging vir jeugbedienings lê daarin dat hierdie moderne tiener uit hulle geestelike verveeldheid uitgehelp sal word sodat hulle iets kan begin doen met dit wat hulle vir jare al weet. Die Tienerleier selgroep model is gerig op die verstaan van Millennium tieners en hulle geestelik te help groei. Met die oop steel in gedagte word elke tiener wat Jesus Christus as 'n werklikheid ontdek het gemotiveer om hierdie werklikheid met 'n ander tiener te gaan deel. / The one billion teenagers in the world (Borgman 1997:3) today are very different than a few years ago. The process to reach them with the Gospel is recently more difficult than ever. As citizens of the Global village they enjoy the entertainment on television and dress in the way the media proclaims. Modern youth are scared of commitment, not really anti-religion but searching for the true God. The youth of today look to the church to show them something, no, SOMEONE but instead the church became boring to them. We need to help them step out of their own boredom and do something with what they know (Hutchcraft 1996:168). With the focus on spiritual growth, and the vacant chair to remind them of their lost friends, the student-led cell group model can be one of the most effective strategies for reaching and serving the teenager of the next century. / Philosophy, Practical and Systematic Theology / M. Diac. (Jeugwerk) Jeugfilosofie Na binne-gerigte jeugbediening Generasies Millennium tiener Tienerleier selgroepe Selgroep byeenkoms Verdeling Vier dodelike dekades Selleier opleiding Bybelse fundering Geloofsgroei Uitreiking Oikos Vermaak Administrasie Volwasse mentors Youth philosophy Inside focus Generations Millennial teenager Student-Led cell groups Cell group meeting Multiply a group Four deadly decades Celleader training Bible foundation Growth in faith Outreach Oikos Entertainment Administration Adult mentors 259.23 Generation X Church group work with teenagers Church work with teenagers Group ministry Church group work with youth
40	Calcul flottant haute performance sur circuits reconfigurables / High-performance floating-point computing on reconfigurable circuits Pasca, Bogdan Mihai 21 September 2011 (has links) De plus en plus de constructeurs proposent des accélérateurs de calculs à base de circuits reconfigurables FPGA, cette technologie présentant bien plus de souplesse que le microprocesseur. Valoriser cette flexibilité dans le domaine de l'accélération de calcul flottant en utilisant les langages de description de circuits classiques (VHDL ou Verilog) reste toutefois très difficile, voire impossible parfois. Cette thèse a contribué au développement du logiciel FloPoCo, qui offre aux utilisateurs familiers avec VHDL un cadre C++ de description d'opérateurs arithmétiques génériques adapté au calcul reconfigurable. Ce cadre distingue explicitement la fonctionnalité combinatoire d'un opérateur, et la problématique de son pipeline pour une précision, une fréquence et un FPGA cible donnés. Afin de pouvoir utiliser FloPoCo pour concevoir des opérateurs haute performance en virgule flottante, il a fallu d'abord concevoir des blocs de bases optimisés. Nous avons d'abord développé des additionneurs pipelinés autour des lignes de propagation de retenue rapides, puis, à l'aide de techniques de pavages, nous avons conçu de gros multiplieurs, possiblement tronqués, utilisant des petits multiplieurs. L'évaluation de fonctions élémentaires en flottant implique souvent l'évaluation en virgule fixe d'une fonction. Nous présentons un opérateur générique de FloPoCo qui prend en entrée l'expression de la fonction à évaluer, avec ses précisions d'entrée et de sortie, et construit un évaluateur polynomial optimisé de cette fonction. Ce bloc de base a permis de développer des opérateurs en virgule flottante pour la racine carrée et l'exponentielle qui améliorent considérablement l'état de l'art. Nous avons aussi travaillé sur des techniques de compilation avancée pour adapter l'exécution d'un code C aux pipelines flexibles de nos opérateurs. FloPoCo a pu ainsi être utilisé pour implanter sur FPGA des applications complètes. / Due to their potential performance and unmatched flexibility, FPGA-based accelerators are part of more and more high-performance computing systems. However, exploiting this flexibility for accelerating floating-point computations by manually using classical circuit description languages (VHDL or Verilog) is very difficult, and sometimes impossible. This thesis has contributed to the development of the FloPoCo software, a C++ framework for describing flexible FPGA-specific arithmetic operators. This framework explicitly separates the description of the combinatorial functionality of an arithmetic operator, and its pipelining for a given precision, operating frequency and target FPGA.In order to be able to use FloPoCo for designing high performance floating-point operators, we first had to design the optimized basic blocks. We first developed pipelined addition architectures exploiting the fast-carry lines present in modern FPGAs. Next, we focused on multiplication architectures. Using tiling techniques, we proposed novel architectures for large multipliers, but also truncated multipliers, based on the multipliers found in modern FPGA DSP blocks. We also present a generic FloPoCo operator which inputs the expression of a function, its input and output precisions, and builds an optimized polynomial evaluator for the fixed-point evaluation of this function. Using this building block we have designed floating-point operators for the square-root and exponential functions which significantly outperform existing operators. Finally, we also made use of advanced compilation techniques for adapting the execution of a C program to the flexible pipelines of our operators. FPGA Virgule flottante FloPoCo Chemin de données arithmétique Pipeline pour une fréquence donnée Addition pipelinée Additionneur rapide Multiplication Karatsuba-Offman Carré Multiplieur tronqué Multiplication par pavage Virgule fixe Approximation polynomiale Racine carrée flottante Exponentielle flottante Accumulation flottante Schéma d'évaluation de Horner Somme de carrés flottante Synthèse de haut niveau Nid de boucles parfait Multiplication de matrices Jacobi Dilemme du fabricant de table Méthode des différences tabulées Communications pipelinées FPGA Floating-point FloPoCo Arithmetic datapath Frequency-driven pipelining Pipelined addition Short-latency adder Multiplication Karatsuba-Offman Squarer Truncated multiplier Multiplication tiling Fixed-point Polynomial approximation Floating-point square root Floating-point exponential Floating-point accumulation Horner datapath Floating-point sum-of-products High-level synthesis Perfect loop nests Matrix-matrix multiply Jacobi stencil Table maker's dilemma Pipelined communications Pipelined communications

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