Angiography is an invasive procedure since contrast medium is injected into circulatory system of patients and the mostly preferred technique is X-ray angiography. For diagnosis, treatment planning, and risk assessment purposes, interventional radiologists utilize visual inspection to determine connectivity relations between vessels. This situation leads angiography to be more invasive, since it requires additional injection of contrast medium and X-ray dose. This thesis work presents a 3-D vascular connectivity tracking toolkit for automated extraction of vascular networks in 3-D medical images. The proposed method automatically extracts the vascular network connected to a user-defined point in a user-defined direction, and requires no further user interaction. The toolkit prevents additional injection of contrast agent and X-ray dose, saves time for the interventional radiologist. While the algorithm is applicable on all 3-D angiography images, performance of the method is observed on 3-D catheter angiography image of cerebrovascular structures. The algorithm iteratively tracks gravity centers of vascular branches in the user-defined direction, preserving connection to the user-defined point. Curvy branches are tracked even if they have discontinuous portions. Since this tracking method does not depend on lumen diameter and intensity differences, branches with stenoses and branches having large intensity difference can be successfully tracked. Skeletonization and junction detection methods are described, which are used to detect the sub branches, indirectly connected to the point. These methods are capable of handling bifurcations, trifurcations, and junctions having more branches. However, false junctions occurring due to superposition of vessels are not eliminated.

No description available.

No description available.

This work theorizes the contemporary attraction to three-dimensional media. In doing so, it reframes ongoing debates surrounding digital three-dimensional media in order to critique the neoliberal social relations such media engender. I argue that the contemporary interest in dimensionality, especially regarding digital media, is symptomatic of a broad cultural shift, wherein millions of lives are now essentially being lived through two-dimensional, "flat" media, which have consequently generated a lack of spatial relationships and a craving or desire for "depth." This "desire for depth" has arisen in contemporary society because people are being "spread too thin" through a combination of the radical connectivity afforded by digital technology and the demand for limitless flexibility imposed by the market: a condition I call hyper-extensionality. My work examines how neoliberal capitalism necessitates the individualized, radical connectivity now experienced by millions of people, and subsequently generates our attraction to three-dimensionality in digital media. Through analyses of select, prominent forms of three-dimensional media, I show that commercial three-dimensional media largely functions to maintain the status quo by helping alleviate the feeling of "depthlessness" in the social unconscious.

In this study, excavation of jet-grouted tunnels in ground with strong time-dependent behavior is analyzed. The constant growth of population has led to a constant increase in the price of lands and thus infrastructures. Underground alternatives are becoming more economical. Furthermore, advances in the construction technology have made it feasible to construct tunnels in difficult ground conditions. By providing a grouted arch ahead of the tunnel face, jet-grouting has proved effective for the stability and performance of tunnels in difficult conditions. Given the limited depth of jet-grouting into the face, the jet-grouted arch is loaded soon after installation, when the rigidity of the grouted material is growing significantly. The simultaneous loading and hardening of the jet-grouting makes the tunnel response depend on the excavation rate. Furthermore, in difficult tunneling conditions, the ground material is associated with highly viscous behavior. This behavior is synonymous with delayed deformation depending on the level and duration of the ground loading by the tunnel excavation. In order to show the importance of the time-dependent behaviors, the full-face and the sequential excavation method are compared using three-dimensional and two-dimensional finite element analyses. First, a three-dimensional model is constructed and its results are validated against available analytical solutions for time-independent behaviors. The hardening of the jet-grouting is then introduced into the model by embedding jet-grouting elements through the analysis. In order to account for the ground viscous behavior, an advanced viscoplastic constitutive model is adopted, numerically implemented in FORTRAN, and used in conjunction with finite element software ABAQUS. The excavation methods are compared for the well documented study case of Tartaiguille tunnel. The results indicate that the full-face method outperforms the sequential method in the studied case by installing the tunnel invert closer to the face. The two-dimensional analysis of the tunnel is conducted by using the convergence-confinement method. To this end, a new approach is introduced to use the method for tunnels in time-dependent conditions. The effect of the jet-grouting hardening and the ground viscous behavior is characterized within the new approach by deriving the ground convergence curves. The reverse dependency of these mechanisms on the tunnel advance rate leads to an optimum advance rate, at which minimum tunnel convergence develops. / text

The research presented in this doctoral dissertation introduces a developmental path to realize micro coaxial transmission lines for wafer-level microwave and millimeter wave circuits. The micro coax lines conceptualized in this research are three-dimensional, with a uniquely low vertical profile of 20 mu m. They are distinguishable from other transmission line topologies due to frequency limitless, cross-talk free performance in high density circuits resulting from the totally shielded construction. Design and optimization was done using equations and electromagnetic simulations. Extensive process development has been carried out to fabricate these devices on CMOS grade silicon wafers using processes amenable to the IC manufacturing industry. Micro coax lines of three different core types including air, semi-dielectric and all-dielectric cores were designed, fabricated and analyzed from 1 - 40 GHz with respect to line impedance and the volume of polyimide (dielectric) in the micro coax cavity. The insertion loss of the lines was found to vary from 2 to 9 dB/cm depending on the width the center conductor, total cross-sectional area and core type. The versatility of the micro coax technology developed in the earlier part of this research has been successfully integrated with RF MEMS to embed a MEM varactor inside the micro coax cavity capable of achieving a capacitance ratio around 7 with an actuation voltage of 40 - 60V. The vertical integration capability of the micro coax was demonstrated by locating a millimeter wave slot antenna on the top side shield of a rectangular micro coax line, also acting as the electromagnetically coupled feed for the antenna. The antenna was designed to operate in the full range of the unlicensed 57 - 64 GHz spectrum capable of Gbps data rates. A 15 dB bandwidth of 17% and a hemispherical radiation pattern was achieved. Lastly, a diversified application involving the application of an integrated micro coax probe-microfluidic chamber approach to detect bacteria through impedance measurements has been introduced. In summary, the development and implementation of micro coax technology on a large scale is bound to create a paradigm shift in the development of high density microwave and millimeter wave circuits for RF MEMS and integrated antennas.

Das Ziel der hier durchgeführten Studie war es, die Möglichkeiten der zerstörungsfreien Untersuchungsmethode, 3-D-Röntgenmikrotomographie, bei der Bewertung von Wurzelkanalfüllungen anhand der modifizierten lateralen Kondensation, der lateralen Kondensation und bei Thermafil zu untersuchen. Es sollte gezeigt werden, dass die einzelnen Bestandteile der Wurzelkanalfüllung zu differenzieren und im Anschluss auch zu quantifizieren sind. Die ersten 21 mit dieser zerstörungsfreien Methode untersuchten Proben wurden im Anschluss nochmals mit einer klassischen Untersuchungsmethode, der Lichtmikroskopie, beurteilt. Die hier erzielten Ergebnisse wurden bei einem Methodenvergleich mit den Ergebnissen der 3-D-Röntgenmikrotomographie verglichen und auf eine mögliche Korrelation überprüft. Ziel war es zu überprüfen, ob verschiedene Methoden zur Qualitätsprüfung von Wurzelkanalfüllungen als gleichwertig angenommen werden können. Im Rahmen dieser Untersuchung wurde eine neue modifizierte laterale Kondensation eingeführt, die hinsichtlich ihrer Qualität anhand der bereits genannten Parameter mit zwei bereits eingeführten Wurzelkanalfüllmethoden verglichen werden sollte. Die 3-D-Röntgenmikrotomographie ermöglichte eine selektive Darstellung der einzelnen Komponenten in 400 bis 750 Ebenen, welche ebenfalls quantifizierbar waren. Es wurden Füllgrade zwischen 71 % und 92 % erzielt. Das Thermafil-System schien den auf lateraler Kondensation basierenden Systemen bezüglich der bestimmten Volumen vereinzelt signifikant überlegen. Bei der lichtmikroskopischen Auswertung ergaben sich diesbezüglich ähnliche Ergebnisse. Die Farbstoffpenetrationstiefen zeigten weder tendenzielle noch signifikante Unterschiede zwischen den einzelnen Fülltechniken. Beim Vergleich der Methoden zur Bewertung der Obturation bezüglich der erhobenen Volumen konnte keine Korrelation nachgewiesen werden. Auch beim Vergleich der Farbstoffpenetrationstiefen und der bestimmten Volumen bei der 3-D-Röntgenmikrotomographie konnten keine Korrelationen ermittelt werden. Unter Berücksichtigung der Grenzen dieser Untersuchung lässt sich festhalten, dass die Methode der 3-D-Röntgenmikrotomographie zur Bewertung und zum Vergleich von Wurzelkanalfüllungen geeignet ist. Die Ergebnisse korrelieren jedoch nicht mit denen der Lichtmikroskopie.

Four studies including ten experiments adresses interrelations between some major and classical issues in visual perception: 3-D perception, colour constancy, colour perception and colour vision deficiencies. The main experimental paradigm to investigate the issues is within that of simulated shape from shading. 3-D impressions are induced by projecting space-modulated illuminations onto flat surfaces (displays), varying the colours and layout of the displays and the colour and modulation of the illumination. Study I includes four experiments investigating three types of space- modulated illumination. All experiments confirmed earlier findings that chromatic colour and complex display layout with reflectance edges crossed by illumination edges enhances shape from shading. In Study II the impressions of shape from shading and real 3-D objects were compared between persons with deutan colour vision deficiencies and normals. As predicted, the deutans show fewer and less distinct 3-D impressions in situations with their specific "problem colours" red and green. They also show a generally lower tendency for 3-D impressions, interpreted as a generally weaker colour constancy. Study III presents the AMBEGUJAS phenomenon; a novel twofold ambiguous shape from shading situation, continuously alternating between two different 3-D impressions coupled with different colour attributions. One solution is of an object with two clear surface colours, the other one of an object with greyish (desaturated) colours in coloured illumination which means classical colour constancy. The phenomenon illustrates the visual processes of separating reflectance and illumination characteristics and may provide a useful experimental setting to study colour constancy. In Study IV the AMBEGUJAS phenomenon is found to be robust as to chromaticness and different luminance contrasts for both normals and deutans. However, the deutans show slower shifts between percepts and a less pronounced desaturation of colour, which indicates a weaker colour constancy. The studies add evidence to the contribution of colour to 3-D shape perception, validated in a novel way by the results on "colour-blinds". The AMBEGUJAS phenomenon provides further support that the factors affecting shape from shading and the deutans different impressions are to be understood with reference to colour constancy. The deutans different impressions compared to normals are remarkable per se, but probably with very limited implications to everyday life. / <p>Diss. (sammanfattning) Umeå : Umeå university, 1996, härtill 4 uppsatser</p> / digitalisering@umu

George Enescu (1881-1955) is known primarily today in conjunction with the world of violin playing. Celebrated as a violin virtuoso throughout the capitals of Europe and North America in the first half of this century, and later admired as a teacher of luminary talents such as Yehudi Menuhin, Arthur Grumiaux, and Ida Haendel, Enescu exerted a considerable influence on the developments of the international music scene. This was nowhere more apparent than in Paris and Bucharest, cities in which Enescu spent most of his life active as performer, conductor, and composer. As his career progressed, Enescu dedicated an increasing amount of time and energy to composition, producing an impressive list of works, many of which were of monumental proportions. Contemporary with Bartok and Kodály, Enescu found himself caught in the current of nationalism that asserted itself in Europe during the first decades of the twentieth century. Seeking a personal, expressive idiom in which he could fuse the musical elements of both Western tradition and his native Rumanian folk heritage, Enescu experimented with diverse compositional trends and styles. Expanding the reaches of tonality with heightened chromaticism, in which microtonal as well as modal inflections were both to play significant roles, Enescu’s idiom evolved into a highly plastic language, comprising a great variety of stylistic characteristics. In order to assimilate the heterogeneous elements into one unified expression, Enescu relied on traditional compositional techniques such as sonata form, cyclic thematic structure, and motivic development. The focus of this paper is to examine to what extent these compositional techniques are incorporated into his work and to direct attention to those elements, i.e., both structural and non-structural, that were most distinctive of Enescu’s musical style. Owing to its concentration of key stylistic elements and its stature as perhaps the most accomplished piano composition in Enescu’s output, the Sonata for Piano in D Major, Op. 24, No. 3 (1934) will serve as model for this analytical study. Chapter One provides by way of an introduction a brief overview of the formative years in Enescu’s life and defines the position of the Sonata within the complete ceuvre. Chapters Two, Three, and Four constitute the main body of the paper and contain analyses of each of the Sonata’s three movements. In these chapters discussion revolves around the more significant structural features of the work such as the overall cyclic design, simultaneously examining the methods Enescu employs to integrate folk inflection throughout the Sonata. Chapter Five comprises the summary. The most significant features of the Sonata are recapitulated and parallels to numerous other works are drawn, in an attempt to present the Sonata as a culmination of Enescu’s compositional style.

L'instabilité des cavités souterraines (mines, carrières, tunnels,...) peut induire les mouvements de terrains d'amplitude suffisante pour endommager les bâtiments et les infrastructures en surface. Les méthodes traditionnelles, utilisées dans les pratiques d'ingénieur pour prévoir les déformations dans les structures, sont basées sur les caractéristiques des mouvements de terrain en condition de terrain vierge sans prendre en compte l'effet de la présence des structures en surface. L'objectif de cette thèse est de prédire les déformations des ouvrages en tenant compte de l'influence de l'interaction sol-structure, d'une part ; et d'évaluer la performance d'une solution de protection (tranchée périphérique), d'autre part. Cela a été achevé par la réalisation d'études paramétriques utilisant deux approches complémentaires : une approche expérimentale à l'aide d'un modèle réduit physique 3D sous gravité normale et une modélisation numérique 3D par la méthode des éléments finis. En particulier l'effet d'un certain nombre de paramètres géométriques et mécaniques a pu être investigué dans l'étude de l'interaction sol-structure : la position de la structure par rapport à la cuvette d'affaissement, le poids de la structure et la raideur relative entre le sol et la structure. Concernant l'étude de l'efficacité de tranchées périphériques, l'effet de la position de la structure, de la position de la tranchée vis-à-vis de la structure et de la rigidité de la tranchée a été analysé. Les résultats obtenus ont abouti à une meilleure compréhension du problème d'interaction sol-structure et ont montré l'importance de cet effet qui doit être pris en compte dans l'évaluation de la vulnérabilité du bâti. Le transfert des mouvements du sol à la structure est faible (moins de 2,5%), dans le cas modélisé : structure rigide et interface glissante. Les différents résultats ont permis par ailleurs de mettre en évidence l'efficacité de la tranchée périphérique pour réduire les sollicitations affectant les structures. La tranchée doit être remplie avec un matériau très déformable et surtout placée à une distance de l'ordre d'un mètre de la structure.