Made available in DSpace on 2014-10-09T12:30:16Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:06:30Z (GMT). No. of bitstreams: 1 01389.pdf: 6990402 bytes, checksum: 16d6c8571bfc43606103b6548556e3df (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

This work is a study of an information theoretic model which is used to develop a complexity measure of an algorithm. The measure is defined to reflect the computational cost and structure of the given algorithm. In this study computational costs are expressed as the execution times of the algorithm, where the algorithm is coded as a program in a machine independent language, and analysed in terms of its representation as a pseudograph. It is shown that this measure aids in deciding which sections of the algorithm should be optimized, segmented or expressed as subprograms. The model proposed is designed to yield a measure which reflects both the program flow and computational cost. Such a measure allows an 'optimal' algorithm to be selected from a set of algorithms, all of which solve the given problem. This selection is made with a more meaningful criterion for decision than simply execution cost. The measure can also be used to further analyse a given algorithm and point to where code optimization techniques should be applied. However it does not yield a method of generating equivalent algorithms. / Science, Faculty of / Computer Science, Department of / Graduate

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The research overviewed in this dissertation concerns highly accurate variational calculations of small molecular systems without assuming the Born--Oppenheimer approximation. The centerpiece of the research is the use of different forms of explicitly correlated Gaussian basis functions. These basis functions allow analytical evaluation of all necessary matrix elements and provide a very powerful tool for solving quantum mechanical problems encountered in various areas of physics. Most of the derivations presented in the dissertation are done within the formalism of matrix differential calculus that has proven to be a very handy and effective way of dealing with explicitly correlated Gaussians. As this fomalism is not widely used in physics or chemistry, some mathematical background is provided. The expressions obtained theoretically were implemented in a computer code that was run quite extensively on several parallel computer systems during the period of the author's Ph.D. study. The results of many such calculations are presented and discussed. The dissertation is primarily based on the content of the papers that were published in coathorship with my scientific advisor and other collaborators in several scientific journals. It also includes some topics that were not considered in the publications but are essential for the completeness and good understanding of the presented work.

Berggren, O. (2014) COMSOL Multiphysics – Ett energitekniskt analysverktyg vid numerisk simulering av köldbryggor och analys av fukt i konstruktionsdetaljer. Examensuppsats i ämnet energiteknik. Institutionen för tillämpad elektronik och fysik vid Umeå Universitet. Konsultföretaget Tyréns har vid sitt kontor i Umeå önskat att utvärdera tillämpningen av programvaran COMSOL Multiphysics. Arbetet bestod av att på nytt simulera och analysera en energiteknisk problemställning, som sedan tidigare ska ha genomförts vid Tyréns. Det valda projektet kallas i detta arbete för referensprojektet och är en del av projekteringen av kulturhuset Väven i Umeå. I referensprojektet behandlas analyserna av köldbryggor och fuktkondensation för flertalet konstruktionsdetaljer, där en av analyserna valdes ut för vidare utvärdering i detta arbete. Målet med utvärderingen var att undersöka om resultaten från arbetet var jämförbara med referensprojektets resultat. I detta ingick det även en presentation av en översiktlig kostnadskalkyl för programvaran COMSOL Multiphysics. Resultaten från analysen av köldbryggan och kondensationen av fukt i konstruktionsdetaljen var i jämförelse med resultaten från referensprojektet något förhöjda, i snitt 20 %. Det genomförda arbetet påvisar att det är möjligt att återskapa de tidigare utförda simuleringarna från referensprojektet i enlighet med det krav och standarder som ställs. De erhållna resultaten är, trots en viss skillnad, jämförbara med de från referensprojektet och är giltiga för att användas vid en verklig projektering. Det slutsatser som kan dras utifrån de erhållna resultaten är att utfall av kondens kan undvikas och att den genomsnittliga värmegenomgångskoefficienten, , indikerar att entrétorgets energiprestanda ej kommer att nå upp till kraven i BBR. Detta trots att -värdet kan antas uppfylla kraven. Då simuleringarna har utförts utan problem i COMSOL Multiphysics och tillgodosett detta arbete med giltiga resultat, anses programvaran vara ett lämpligt simuleringsverktyg hos Tyréns. Kostnaden är dock för en flytande licens av Flixo, i jämförelse till COMSOL Multiphysics mycket lägre. COMSOL Multiphysics är vid utredningstillfället drygt fyra gånger så kostsamt. Fördelen med COMSOL Multiphysics är dock att det kan behandla flera olika typer av fysikaliska problemställningar i en-, två- och tredimensioner med endast grundprogrammet. För att användningen av COMSOL Multiphysics ska vara ekonomisk försvarbart, krävs det att programvaran också används vid tillämpningar utöver simuleringar kring köldbryggor och kondensation av fukt. / Berggren, O. (2014) COMSOL Multiphysics – An analysis tool for energy applications when conducting numerical simulations on thermal bridges and analysis of moisture in construction details. Master thesis in Energy Engineering. Department of Applied Physics and Electronics at Umeå University. The consultant company Tyréns has at its office in Umeå decided to evaluate the application of the software COMSOL Multiphysics.  The evaluation consisted of a simulation on an energy engineering problem with its origin from a project at Tyréns, performed in COMSOL Multiphysics. The chosen project for this task was a part of the design plans of the culture house Väven in Umeå. These design plans includes the analysis of a thermal bridge and moisture on a variety of construction details, where one of them was selected to be investigated further. The main purpose of the investigation was to analyze if the results obtained from the simulations performed in COMSOL Multiphysics were equivalent compared to the results from the design plans. The investigation also included the presentation of an overall cost estimation for the software COMSOL Multiphysics. The obtained results from the analysis of the thermal bridge and moisture in the construction were in both cases slightly raised compared to the results from the design plans, in average an increase of 20 %. The work undertaken concludes that there is fully possible to recreate the previously executed simulations extracted from the design plans in accordance to the requirements and standards that are set. The obtained results are equivalent, even though a minor difference, compared with the results from the design plans and are valid too be used in a real life scenario. The obtained conclusions are that it is possible to prevent moisture in the construction detail. However, the overall U-value, , indicates that the energy efficiency of the entrance square is not good enough to reach the requirements of the SNBBP (Swedish National Board of Housing, Building and Planning). Even though the U-value for the construction detail, , can be assumed to meet the criteria’s of the SNBBP. Due to the fact that the simulations were conducted with COMSOL Multiphysics without any major problems and provided valid results, it is considered that the software is an appropriate tool to perform simulations at Tyréns. However, the cost for a floating license of the software Flixo is much less then for COMSOL Multiphysics. COMSOL Multiphysics is at the time of this study four times as expensive as Flixo. COMSOL Multiphysics has though an advantage because it can treat problems with a multiphysical nature in one, two and three dimensions with the use of only its standard edition. To ensure that the use of COMSOL Multiphysics can be economical viable, it is necessary that the software is used in multiple applications besides performing simulations on thermal bridges and moisture in construction details.

This thesis is missing pages 152 and 194, neither of which are in the other copies of this thesis. -Digitization Centre / Restricted Hartree-Fock calculations for light even-even nuclei have been carried out using simple effective interactions. The primary emphasis is on the nature of the intrinsic states, and, in particular, on the deformation of these states. In order to find the equilibrium deformations a representation of deformed cylindrically symmetric states is used. A self-consistent technique for finding the equilibrium size and shape is proposed. There is a strong secondary emphasis on the role of the effective interaction, and four rather different interactions are used. Two of these incorporate a dependence on the density on the nuclear system, and this density dependence improves the systematic behaviour of the energies and sizes of light nuclei. / Thesis / Doctor of Philosophy (PhD)

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The LHC has begun collecting data and the first results have now been published. This is truly an exciting time in the field as we wait for the experimental data to exclude or verify new physics beyond the Standard Model. In order to make a precise prediction for the LHC one must go beyond the leading order of our perturbation series. In this thesis I present the extension of tools for the automation of one loop calculations for supersymmetric models. The second part of the thesis contains the application of these tools to neutralino pair production in the Minimal Supersymmetric Model.