127 research outputs found
Master index
Pla general, del mural cerĂ mic que decora una de les parets del vestĂbul de la Facultat de QuĂmica de la UB. El mural representa diversos sĂmbols relacionats amb la quĂmica
Methods for testing of analog circuits
PrĂĄce se zabĂœvĂĄ metodami pro testovĂĄnĂ lineĂĄrnĂch analogovĂœch obvodĆŻ v kmitoÄtovĂ© oblasti. CĂlem je navrhnout efektivnĂ metody pro automatickĂ© generovĂĄnĂ testovacĂho plĂĄnu. SnĂĆŸenĂm poÄtu mÄĆenĂ a vĂœpoÄetnĂ nĂĄroÄnosti lze vĂœraznÄ snĂĆŸit nĂĄklady za testovĂĄnĂ. PrĂĄce se zabĂœvĂĄ multifrekveÄnĂ parametrickou poruchovou analĂœzou, kterĂĄ byla plnÄ implementovĂĄna do programu Matlab. Vhodnou volbou testovacĂch kmitoÄtĆŻ lze potlaÄit chyby mÄĆenĂ a chyby zpĆŻsobenĂ© vĂœrobnĂmi tolerancemi obvodovĂœch prvkĆŻ. NavrĆŸenĂ© metody pro optimĂĄlnĂ volbu kmitoÄtĆŻ byly statisticky ovÄĆeny metodou MonteCarlo. Pro zvĂœĆĄenĂ pĆesnosti a snĂĆŸenĂ vĂœpoÄetnĂ nĂĄroÄnosti poruchovĂ© analĂœzy byly vyvinuty postupy zaloĆŸenĂ© na metodÄ nejmenĆĄĂch ÄtvercĆŻ a pĆibliĆŸnĂ© symbolickĂ© analĂœze.The thesis deals with methods for testing of linear analog circuits in the frequency domain. The goal is to develop new efficient methods for automatic test plan generation. To reduce test costs a minimum number of measurements as well as less computational demands are the fundamental aims. The thesis is focused on the multi-frequency parametric fault diagnosis which was fully implemented in the Matlab program. The fundamental problem consists in selection of test frequencies which can reduce the influences of measurement errors and errors caused by tolerances of well-working components. The proposed methods for test frequency selection were statistically verified by the MonteCarlo method. To improve the accuracy and reduce the computational complexity of fault diagnosis, the methods based on least-square techniques and approximate symbolic analysis were presented.
RTNI - A symbolic integrator for Haar-random tensor networks
We provide a computer algebra package called Random Tensor Network Integrator
(RTNI). It allows to compute averages of tensor networks containing multiple
Haar-distributed random unitary matrices and deterministic symbolic tensors.
Such tensor networks are represented as multigraphs, with vertices
corresponding to tensors or random unitaries and edges corresponding to tensor
contractions. Input and output spaces of random unitaries may be subdivided
into arbitrary tensor factors, with dimensions treated symbolically. The
algorithm implements the graphical Weingarten calculus and produces a weighted
sum of tensor networks representing the average over the unitary group. We
illustrate the use of this algorithmic tool on some examples from quantum
information theory, including entropy calculations for random tensor network
states as considered in toy models for holographic duality. Mathematica and
Python implementations are supplied.Comment: Code available (for Mathematica and python) at
https://github.com/MotohisaFukuda/RTN
The SM and NLO multileg working group: Summary report
This report summarizes the activities of the SM and NLO Multileg Working
Group of the Workshop "Physics at TeV Colliders", Les Houches, France 8-26
June, 2009.Comment: 169 pages, Report of the SM and NLO Multileg Working Group for the
Workshop "Physics at TeV Colliders", Les Houches, France 8-26 June, 200
Topics in Programming Languages, a Philosophical Analysis through the case of Prolog
[EN]Programming languages seldom find proper anchorage in philosophy of logic, language and science. is more, philosophy of language seems to be restricted to natural languages and linguistics, and even philosophy of logic is rarely framed into programming languages topics. The logic programming paradigm and Prolog are, thus, the most adequate paradigm and programming language to work on this subject, combining natural language processing and linguistics, logic programming and constriction methodology on both algorithms and procedures, on an overall philosophizing declarative status. Not only this, but the dimension of the Fifth Generation Computer system related to strong Al wherein Prolog took a major role. and its historical frame in the very crucial dialectic between procedural and declarative paradigms, structuralist and empiricist biases, serves, in exemplar form, to treat straight ahead philosophy of logic, language and science in the contemporaneous age as well.
In recounting Prolog's philosophical, mechanical and algorithmic harbingers, the opportunity is open to various routes. We herein shall exemplify some:
- the mechanical-computational background explored by Pascal, Leibniz, Boole, Jacquard, Babbage, Konrad Zuse, until reaching to the ACE (Alan Turing) and EDVAC (von Neumann), offering the backbone in computer architecture, and the work of Turing, Church, Gödel, Kleene, von Neumann, Shannon, and others on computability, in parallel lines, throughly studied in detail, permit us to interpret ahead the evolving realm of programming languages. The proper line from lambda-calculus, to the Algol-family, the declarative and procedural split with the C language and Prolog, and the ensuing branching and programming languages explosion and further delimitation, are thereupon inspected as to relate them with the proper syntax, semantics and philosophical élan of logic programming and Prolog
Programmiersprachen und Rechenkonzepte
Die GI-Fachgruppe 2.1.4 "Programmiersprachen und Rechenkonzepte" veranstaltete vom 3. bis 5. Mai 2004 im Physikzentrum Bad Honnef ihren jĂ€hrlichen Workshop. Dieser Bericht enthĂ€lt eine Zusammenstellung der BeitrĂ€ge. Das Treffen diente wie in jedem Jahr gegenseitigem Kennenlernen, der Vertiefung gegenseitiger Kontakte, der Vorstellung neuer Arbeiten und Ergebnisse und vor allem der intensiven Diskussion. Ein breites Spektrum von BeitrĂ€gen, von theoretischen Grundlagen ĂŒber Programmentwicklung, Sprachdesign, Softwaretechnik und Objektorientierung bis hin zur ĂŒberraschend langen Geschichte der Rechenautomaten seit der Antike bildete ein interessantes und abwechlungsreiches Programm. Unter anderem waren imperative, funktionale und funktional-logische Sprachen, Software/Hardware-Codesign, Semantik, Web-Programmierung und Softwaretechnik, generative Programmierung, Aspekte und formale TestunterstĂŒtzung Thema. Interessante BeitrĂ€ge zu diesen und weiteren Themen gaben AnlaĂ zu Erfahrungsaustausch und FachgesprĂ€chen auch mit den Teilnehmern des zeitgleich im Physikzentrum Bad Honnef stattfindenden Workshops "Reengineering". Allen Teilnehmern möchte ich dafĂŒr danken, daĂ sie mit ihren VortrĂ€gen und konstruktiven DiskussionsbeitrĂ€gen zum Gelingen des Workshops beigetragen haben. Dank fĂŒr die Vielfalt und QualitĂ€t der BeitrĂ€ge gebĂŒhrt den Autoren. Ein Wort des Dankes gebĂŒhrt ebenso den Mitarbeitern und der Leitung des Physikzentrums Bad Honnef fĂŒr die gewohnte angenehme und anregende AtmosphĂ€re und umfassende Betreuung
Implementation and Evaluation of Algorithmic Skeletons: Parallelisation of Computer Algebra Algorithms
This thesis presents design and implementation approaches for the parallel algorithms of computer algebra. We use algorithmic skeletons and also further approaches, like data parallel arithmetic and actors. We have implemented skeletons for divide and conquer algorithms and some special parallel loops, that we call ârepeated computation with a possibility of premature terminationâ. We introduce in this thesis a rational data parallel arithmetic. We focus on parallel symbolic computation algorithms, for these algorithms our arithmetic provides a generic parallelisation approach.
The implementation is carried out in Eden, a parallel functional programming language based on Haskell. This choice enables us to encode both the skeletons and the programs in the same language. Moreover, it allows us to refrain from using two different languagesâone for the implementation and one for the interfaceâfor our implementation of computer algebra algorithms.
Further, this thesis presents methods for evaluation and estimation of parallel execution times. We partition the parallel execution time into two components. One of them accounts for the quality of the parallelisation, we call it the âparallel penaltyâ. The other is the sequential execution time. For the estimation, we predict both components separately, using statistical methods. This enables very confident estimations, although using drastically less measurement points than other methods. We have applied both our evaluation and estimation approaches to the parallel programs presented in this thesis. We haven also used existing estimation methods.
We developed divide and conquer skeletons for the implementation of fast parallel multiplication. We have implemented the Karatsuba algorithm, Strassenâs matrix multiplication algorithm and the fast Fourier transform. The latter was used to implement polynomial convolution that leads to a further fast multiplication algorithm. Specially for our implementation of Strassen algorithm we have designed and implemented a divide and conquer skeleton basing on actors. We have implemented the parallel fast Fourier transform, and not only did we use new divide and conquer skeletons, but also developed a map-and-transpose skeleton. It enables good parallelisation of the Fourier transform. The parallelisation of Karatsuba multiplication shows a very good performance. We have analysed the parallel penalty of our programs and compared it to the serial fractionâan approach, known from literature. We also performed execution time estimations of our divide and conquer programs.
This thesis presents a parallel map+reduce skeleton scheme. It allows us to combine the usual parallel map skeletons, like parMap, farm, workpool, with a premature termination property. We use this to implement the so-called âparallel repeated computationâ, a special form of a speculative parallel loop. We have implemented two probabilistic primality tests: the RabinâMiller test and the Jacobi sum test. We parallelised both with our approach. We analysed the task distribution and stated the fitting configurations of the Jacobi sum test. We have shown formally that the Jacobi sum test can be implemented in parallel. Subsequently, we parallelised it, analysed the load balancing issues, and produced an optimisation. The latter enabled a good implementation, as verified using the parallel penalty. We have also estimated the performance of the tests for further input sizes and numbers of processing elements. Parallelisation of the Jacobi sum test and our generic parallelisation scheme for the repeated computation is our original contribution.
The data parallel arithmetic was defined not only for integers, which is already known, but also for rationals. We handled the common factors of the numerator or denominator of the fraction with the modulus in a novel manner. This is required to obtain a true multiple-residue arithmetic, a novel result of our research. Using these mathematical advances, we have parallelised the determinant computation using the GauĂ elimination. As always, we have performed task distribution analysis and estimation of the parallel execution time of our implementation. A similar computation in Maple emphasised the potential of our approach. Data parallel arithmetic enables parallelisation of entire classes of computer algebra algorithms.
Summarising, this thesis presents and thoroughly evaluates new and existing design decisions for high-level parallelisations of computer algebra algorithms
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