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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Grafické demo v OpenGL řízené hudbou / Graphics Demo in OpenGL Controlled by Music

Koza, Tomáš Unknown Date (has links)
The goal of this thesis was to create graphical demo in OpenGL, which would appropriately react on music, which is inseparable part of graphical demos. Work consists of two main parts, first is programming of real-time graphical engine, second is creating graphical demo which would run on graphical engine created in first part. First part focues on programming of OpenGL based application, which would render scene in real-time using techniques from computer graphics. Second part focuses mainly on graphical activity, which includes 3D modelling, texturing, creating animation and connection to music (reaction of environment and animations to changes in music)
52

Chip-last embedded low temperature interconnections with chip-first dimensions

Choudhury, Abhishek 18 November 2010 (has links)
Small form-factor packages with high integration density are driving the innovations in chip-to-package interconnections. Metallurgical interconnections have evolved from the conventional eutectic and lead-free solders to fine pitch copper pillars with lead-free solder cap. However, scaling down the bump pitch below 50-80µm and increasing the interconnect density with this approach creates a challenge in terms of accurate solder mask lithography and joint reliability with low stand-off heights. Going beyond the state of the art flip-chip interconnection technology to achieve ultra-fine bump pitch and high reliability requires a fundamentally- different approach towards highly functional and integrated systems. This research demonstrates a low-profile copper-to-copper interconnect material and process approach with less than 20µm total height using adhesive bonding at lower temperature than other state-of-the-art methods. The research focuses on: (1) exploring a novel solution for ultra-fine pitch (< 30µm) interconnections, (2) advanced materials and assembly process for copper-to-copper interconnections, and (3) design, fabrication and characterization of test vehicles for reliability and failure analysis of the interconnection. This research represents the first demonstration of ultra-fine pitch Cu-to-Cu interconnection below 200°C using non-conductive film (NCF) as an adhesive to achieve bonding between silicon die and organic substrate. The fabrication process optimization and characterization of copper bumps, NCF and build-up substrate was performed as a part of the study. The test vehicles were studied for mechanical reliability performance under unbiased highly accelerated stress test (U-HAST), high temperature storage (HTS) and thermal shock test (TST). This robust interconnect scheme was also shown to perform well with different die sizes, die thicknesses and with embedded dies. A simple and reliable, low-cost and low-temperature direct Cu-Cu bonding was demonstrated offering a potential solution for future flip chip packages as well as with chip-last embedded active devices in organic substrates.
53

Electroplated multi-path compliant copper interconnects for flip-chip packages

Okereke, Raphael Ifeanyi 22 May 2014 (has links)
The international technology roadmap for semiconductors (ITRS) 2012 report foresees the use of porous dielectric materials with a low dielectric constant in conjunction with copper interconnects as a way to reduce the resistive-capacitive (RC) delay in microelectronic applications. However, the introduction of pores in the dielectric not only serves as stress raisers but also diminishes the structural strength of the material. The challenge therefore with the implementation of low-k dielectrics for high-performance flip-chip packages is to create a reliable die to organic substrate interconnect solution which induces low stresses on the die to prevent the cohesive cracking and the interfacial delamination of the dielectric material. Potential interconnect solutions that meet this challenge are MEMS-like compliant freestanding micro-structures. These structures are designed to work as spring-like elements which allow the free lateral and out-of-plane motion between the silicon die and the organic substrate under assembly conditions as well as under thermal or power cycling. Thus, the focus of this research is to design, fabricate, and characterize electrically and mechanically an innovative compliant interconnect approach that addresses these challenges. The proposed interconnect is scalable in dimensions and pitch, and consists multiple electrical paths which will provide redundancy against interconnect failure. The multi-path design employs parallel electrical paths which effectively split a larger cross-sectional area into several smaller areas making the overall design more compliant than otherwise. This research proposes wafer-level, high-yield, CMOS-compatible fabrication procedure using sequential photolithography and copper electroplating. The proposed interconnects are symmetric and are amenable to easy reflow assembly to substrates. The mechanical compliance of the fabricated structures is studied through nano-indentation, while the electrical characteristics are assessed through fabricated prototypes. The xvi thermo-mechanical reliability of compliant interconnects is also demonstrated. Lastly, the dimensional scalability of the interconnects is also demonstrated.
54

Interactive Volume Rendering For Medical Images

Orhun, Koray 01 September 2004 (has links) (PDF)
Volume rendering is one of the branches of scientific visualization. Its popularity has grown in the recent years, and due to the increase in the computation speed of the graphics hardware of the desktop systems, became more and more accessible. Visualizing volumetric datasets using volume rendering technique requires a large amount of trilinear interpolation operations that are computationally expensive. This situation used to restrict volume rendering methods to be used only in high-end graphics workstations or with special-purpose hardware. In this thesis, an application tool has been developed using hardware accelerated volume rendering techniques on commercial graphics processing devices. This implementation has been developed with a 3D texture based approach using bump mapping for building an illumination model with OpenGL API. The aim of this work is to propose visualization methods and tools for rendering medical image datasets at interactive rates. The methods and tool are validated and compared with a commercially available software.
55

Numerical study for acoustic micro-imaging of three dimensional microelectronic packages

Chean Shen, Lee January 2014 (has links)
Complex structures and multiple interfaces of modern microelectronic packages complicate the interpretation of acoustic data. This study has four novel contributions. 1) Contributions to the finite element method. 2) Novel approaches to reduce computational cost. 3) New post processing technologies to interpret the simulation data. 4) Formation of theoretical guidance for acoustic image interpretation. The impact of simulation resolution on the numerical dispersion error and the exploration of quadrilateral infinite boundaries make up the first part of this thesis's contributions. The former focuses on establishing the convergence score of varying resolution densities in the time and spatial domain against a very high fidelity numerical solution. The latter evaluates the configuration of quadrilateral infinite boundaries in comparison against traditional circular infinite boundaries and quadrilateral Perfectly Matched Layers. The second part of this study features the modelling of a flip chip with a 140µm solder bump assembly, which is implemented with a 230MHz virtual raster scanning transducer with a spot size of 17µm. The Virtual Transducer was designed to reduce the total numerical elements from hundreds of millions to hundreds of thousands. Thirdly, two techniques are invented to analyze and evaluate simulated acoustic data: 1) The C-Line plot is a 2D max plot of specific gate interfaces that allows quantitative characterization of acoustic phenomena. 2) The Acoustic Propagation Map, contour maps an overall summary of intra sample wave propagation across the time domain in one image. Lastly, combining all the developments. The physical mechanics of edge effects was studied and verified against experimental data. A direct relationship between transducer spot size and edge effect severity was established. At regions with edge effect, the acoustic pulse interfacing with the solder bump edge is scattered mainly along the horizontal axis. The edge effect did not manifest in solder bump models without Under Bump Metallization (UBM). Measurements found acoustic penetration improvements of up to 44% with the removal of (UBM). Other acoustic mechanisms were also discovered and explored. Defect detection mechanism was investigated by modelling crack propagation in the solder bump assembly. Gradual progression of the crack was found have a predictable influence on the edge effect profile. By exploiting this feature, the progress of crack propagation from experimental data can be interpreted by evaluating the C-Scan image.
56

Přestavba experimentálního vozidla Formula Faster / Experimental Car Formula Faster Rebuild

Zarambukas, Michalis January 2011 (has links)
The main purpose of this diploma thesis is the experimental vehicle Formula Faster engine reconstruction. The current Ford Kent 1600cc engine will be replace by the Škoda 1.4 MPI engine. The next task is to analyse kinematic properties of the front axle and subsequent optimization and transformation of steering rod placing which relates to wheel toe and bump travel. The last part is concerned with steering wheel mounting transformation, concretely with reconstruction to obtain removable steering wheel using rapid coupling.
57

Pair Cascades in Blazars and Radio Galaxies

Roustazadeh Sheikhyousefi, Parisa 18 April 2012 (has links)
No description available.
58

Validation and Inferential Methods for Distributional Form and Shape

Mayorov, Kirill January 2017 (has links)
This thesis investigates some problems related to the form and shape of statistical distributions with the main focus on goodness of fit and bump hunting. A bump is a distinctive characteristic of distributional shape. A search for bumps, or bump hunting, in a probability density function (PDF) has long been an important topic in statistical research. We introduce a new definition of a bump which relies on the notion of the curvature of a planar curve. We then propose a new method for bump hunting which is based on a kernel density estimator of the unknown PDF. The method gives not only the number of bumps but also the location of their centers and base points. In quantitative risk applications, the selection of distributions that properly capture upper tail behavior is essential for accurate modeling. We study tests of distributional form, or goodness-of-fit (GoF) tests, that assess simple hypotheses, i.e., when the parameters of the hypothesized distribution are completely specified. From theoretical and practical perspectives, we analyze the limiting properties of a family of weighted Cramér-von Mises GoF statistics W2 with weight function psi(t)=1/(1-t)^beta (for beta<=2) which focus on the upper tail. We demonstrate that W2 has no limiting distribution. For this reason, we provide a normalization of W2 that leads to a non-degenerate limiting distribution. Further, we study W2 for composite hypotheses, i.e., when distributional parameters must be estimated from a sample at hand. When the hypothesized distribution is heavy-tailed, we examine the finite sample properties of W2 under the Chen-Balakrishnan transformation that reduces the original GoF test (the direct test) to a test for normality (the indirect test). In particular, we compare the statistical level and power of the pairs of direct and indirect tests. We observe that decisions made by the direct and indirect tests agree well, and in many cases they become independent as sample size grows. / Thesis / Doctor of Philosophy (PhD)
59

The dynamics of Alfvén eigenmodes excited by energetic ions in toroidal plasmas

Tholerus, Emmi January 2016 (has links)
The future fusion power plants that are based on magnetic confinement will deal with plasmas that inevitably contain energetic (non-thermal) particles. These particles come, for instance, from fusion reactions or from external heating of the plasma. Ensembles of energetic ions can excite eigenmodes in the Alfvén frequency range to such an extent that the resulting wave fields redistribute the energetic ions, and potentially eject them from the plasma. The redistribution of ions may cause a substantial reduction of heating efficiency. Understanding the dynamics of such instabilities is necessary to optimise the operation of fusion experiments and of future fusion power plants. Two models have been developed to simulate the interaction between energetic ions and Alfvén eigenmodes. One is a bump-on-tail model, of which two versions have been developed: one fully nonlinear and one quasilinear. The quasilinear version has a lower dimensionality of particle phase space than the nonlinear one. Unlike previous similar studies, the bump-on-tail model contains a decorrelation of the wave-particle phase in order to model stochasticity of the system. When the characteristic time scale for macroscopic phase decorrelation is similar to or shorter than the time scale of nonlinear wave-particle dynamics, the nonlinear and the quasilinear descriptions quantitatively agree. A finite phase decorrelation changes the growth rate and the saturation amplitude of the wave mode in systems with an inverted energy distribution around the wave-particle resonance. Analytical expressions for the correction of the growth rate and the saturation amplitude have been derived, which agree well with numerical simulations. A relatively weak phase decorrelation also diminishes frequency chirping events of the eigenmode. The second model is called FOXTAIL, and it has a wider regime of validity than the bump-on-tail model. FOXTAIL is able to simulate systems with multiple eigenmodes, and it includes effects of different individual particle orbits relative to the wave fields. Simulations with FOXTAIL and the nonlinear bump-on-tail model have been compared in order to determine the regimes of validity of the bump-on-tail model quantitatively. Studies of two-mode scenarios confirmed the expected consequences of a fulfillment of the Chirikov criterion for resonance overlap. The influence of ICRH on the eigenmode-energetic ion system has also been studied, showing qualitatively similar effects as seen by the presence of phase decorrelation. Another model, describing the efficiency of fast wave current drive, has been developed in order to study the influence of passive components close to the antenna, in which currents can be induced by the antenna generated wave field. It was found that the directivity of the launched wave, averaged over model parameters, was lowered by the presence of passive components in general, except for low values of the single pass damping of the wave, where the directivity was slightly increased, but reversed in the toroidal direction. / De framtida fusionskraftverken baserade på magnetisk inneslutning kommer att hantera plasmor som oundvikligen innehåller energetiska (icke-termiska) partiklar. Dessa partiklar kommer exempelvis från fusionsreaktioner eller från externa uppvärmningsmekanismer av plasmat. Ensembler av energetiska joner kan excitera egenmoder i Alfvén-frekvensområdet i en sådan utsträckning att de resulterande vågfälten omfördelar de energetiska jonerna i rummet, och potentiellt slungar ut jonerna ur plasmat. Omfördelningen av joner kan orsaka en väsentligen minskad uppvärmningseffekt. Det är nödvändigt att förstå dynamiken hos denna typ av instabilitet för att kunna optimera verkningsgraden hos experiment och hos framtida fusionskraftverk. Två modeller har utvecklats för att simulera interaktionen mellan energetiska joner och Alfvén-egenmoder. Den första är en bump-on-tail-modell, av vilken två versioner har utvecklats: en fullt icke-linjär och en kvasi-linjär. I den kvasi-linjära versionen har partiklarnas fasrum en lägre dimensionalitet än i den icke-linjära versionen. Till skillnad från tidigare liknande studier innehåller denna bump-on-tail-modell en dekorrelation av våg-partikelfasen för att modellera stokasticitet hos systemet. När den karakteristiska tidsskalan för makroskopisk fasdekorrelation är ungefär samma som eller kortare än tidsskalan för icke-linjär våg-partikeldynamik så stämmer den icke-linjära och den kvasi-linjära beskrivningen överens kvantitativt. En ändlig fasdekorrelation förändrar vågmodens tillväxthastighet och satureringsamplitud i system med en inverterad energifördelning omkring våg-partikelresonansen. Analytiska uttryck för korrektionen av tillväxthastigheten och satureringsamplituden har härletts, vilka stämmer väl överens med numeriska simuleringar. En relativt svag fasdekorrelation försvagar även "frequency chirping events" (snabba frekvensskiftningar i korttids-Fourier-transformen av egenmodens amplitudutveckling) hos egenmoden. Den andra modellen, kallad FOXTAIL, har ett mycket bredare giltighetsområde än bump-on-tail-modellen. FOXTAIL kan simulera system med flera egenmoder, och den inkluderar effekter av olika enskilda partikelbanor relativt vågfälten. Simuleringar med FOXTAIL och med bump-on-tail-modellen har jämförts för att kvantitativt bestämma bump-on-tail-modellens giltighetsområde. Studier av scenarier med två egenmoder bekräftar de förväntade effekterna av när Chirikov-kriteriet för resonansöverlapp uppfylls. Även inflytandet av ICRH på dynamiken mellan egenmoder och energetiska joner har studerats, vilket har visat kvalitativt liknande effekter som har observerats i närvaron av fasdekorrelation. En annan modell, vilken beskriver effektiviteten hos "fast wave current drive" (strömdrivning med snabba magnetosoniska vågor), har utvecklats för att studera inflytandet av passiva komponenter nära antennen, i vilka strömmar kan induceras av vågfälten som genereras av antennen. Det visades att den utskickade vågens direktivitet, medelvärdesbildat över modellparametrar, generellt sett minskade vid närvaron av passiva komponenter, förutom vid låg "sinlge pass damping" (dämpning av vågen vid propagering genom hela plasmat), då direktiviteten istället ökade något, men bytte tecken i toroidal riktning. / <p>QC 20160927</p>
60

Introduction to some modes of convergence : Theory and applications

Bolibrzuch, Milosz January 2017 (has links)
This thesis aims to provide a brief exposition of some chosen modes of convergence; namely uniform convergence, pointwise convergence and L1 convergence. Theoretical discussion is complemented by simple applications to scientific computing. The latter include solving differential equations with various methods and estimating the convergence, as well as modelling problematic situations to investigate odd behaviors of usually convergent methods.

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