Global P wave tomography of Earth's lowermost mantle from partition modeling

Determining the scale-length, magnitude, and distribution of heterogeneity in the lowermost mantle is crucial to understanding whole mantle dynamics, and yet it remains a much debated and ongoing challenge in geophysics. Common shortcomings of current se

Earth's structure from a bayesian analysis of seismic signals and noise

The prevailing drive of modern seismology is to improve our knowledge of the Earth's structure, composition, and dynamics through an analysis of seismic waveforms. With increasing computing power, number and quality of seismic stations, and length of data records, the resolution and spatial coverage of current Earth models has improved substantially over the past few decades. Yet many limitations remain. The advent of ambient noise seismology has provided the solution to many issues, such as the irregular distribution of earthquakes, biases from structures outside the model region, earthquake location errors, and lack of near-surface resolution. Despite improvements to data quality and quantity and the introduction of unconventional datasets such as ambient seismic noise, a persisting shortcoming of many tomographic inversions is ad-hoc error estimation, parameterization, and regularization, which prevent a meaningful portrayal of model complexity and uncertainty. With the rapid increase in computing power, non-linear techniques based on densely sampling favorable regions of model space are now becoming tractable for real-world tomographic problems and directly address these shortcomings. One such recently introduced and promising method is transdimensional and hierarchical Bayesian inference. This alternate approach allows model parameterization and resolution to be driven by the data. This thesis presents a collection of seismic inverse problems using real world datasets, some of which are tackled using fully non-linear Bayesian statistics. The benefits of a probabilistic approach are demonstrated for datasets targeting the uppermost crust down to the core through the development of novel methods of inversion and uncertainty quantification. To begin, an unconventional methodology for studying earthquake focal mechanisms in intraplate settings is presented through the inversion of ambient noise, receiver functions, and dispersion curves. The ambient seismic noise imaging approach of this study is subsequently applied to Tasmania - to which it is highly suited - and the resulting group and phase velocity maps help decipher Tasmania's enigmatic tectonic history. The same ambient noise dataset is further manipulated to yield a 3D shear velocity model of the region using a two-step transdimensional, hierarchical ensemble inference approach. Two prominent low-velocity anomalies offer insight into the Paleozoic evolution of the east Gondwana margin and support a connection between Tasmania and mainland Australia since the Cambrian. This approach is also applied to a larger dataset encompassing much of mainland southeast Australia. The Bayesian approach is also applied to a global dataset of differential body wave travel times in an effort to reveal P-wave velocity heterogeneity in the lowermost mantle. Another deep Earth application is demonstrated through an inversion for the time-dependent differential rotation of the inner core with respect to the rest of the mantle using careful measurements of earthquake doublets. The transdimensional nature of the inversion problem means that the data drive the number of free parameters constraining the differential rotation pattern, which exhibits much more complexity than the simple linear trend long-promoted by previous studies. The contents of this thesis help augment the diverse and wide-reaching applications for Bayesian statistics, which will continue to improve with future increases in computational power

Signal Modeling for Two-Dimensional Image Structures and Scale-Space Based Image Analysis

Model based image representation plays an important role in many computer vision tasks. Consequently, it is of high significance to model image structures with more powerful representation capabilities. In the literature, there exist bulk of researches for intensity based modeling. However, most of them suffer from the illumination variation. On the other hand, phase information, which carries most essential structural information of the original signal, has the advantage of being invariant to the brightness change. Therefore, phase based image analysis is advantageous when compared to purely intensity based approaches. This thesis aims to propose novel image representations for 2D image structures, from which useful local features can be extracted, which are useful for phase based image analysis. The first approach presents a 2D rotationally invariant quadrature filter. This model is able to handle superimposed intrinsically two-dimensional (i2D) patterns with flexible angles of intersection. Hence, it can be regarded as an extension of the structure multivector. The second approach is the monogenic curvature tensor. Coupling methods of differential geometry, tensor algebra, monogenic signal and quadrature filter, we can design a general model for 2D structures as the monogenic extension of a curvature tensor. Based on it, local representations for the intrinsically one-dimensional (i1D) and i2D structures are derived as the monogenic signal and the generalized monogenic curvature signal, respectively. From them, independent features of local amplitude, phase and orientation are simultaneously extracted. Besides, a generalized monogenic curvature scale-space can be built by applying a Poisson kernel to the monogenic curvature tensor. Compared with other related work, the remarkable advantage of our approach lies in the rotationally invariant phase evaluation of 2D structures in a multi-scale framework, which delivers access to phase-based processing in many computer vision tasks. To demonstrate the efficiency and power of the theoretic framework, some computer vision applications are presented, which include the phase based image reconstruction, detecting i2D image structures using local phase and monogenic curvature tensor for optical flow estimation

Extended Abstracts

Presented at the 21st International Conference on Auditory Display (ICAD2015), July 6-10, 2015, Graz, Styria, Austria.Mark Ballora “Two examples of sonification for viewer engagement: Hurricanes and squirrel hibernation cycles” / Stephen Barrass, “ Diagnostic Singing Bowls” / Natasha Barrett, Kristian Nymoen. “Investigations in coarticulated performance gestures using interactive parameter-mapping 3D sonification” / Lapo Boschi, Arthur Paté, Benjamin Holtzman, Jean-Loïc le Carrou. “Can auditory display help us categorize seismic signals?” / Cédric Camier, François-Xavier Féron, Julien Boissinot, Catherine Guastavino. “Tracking moving sounds: Perception of spatial figures” / Coralie Diatkine, Stéphanie Bertet, Miguel Ortiz. “Towards the holistic spatialization of multiple sound sources in 3D, implementation using ambisonics to binaural technique” / S. Maryam FakhrHosseini, Paul Kirby, Myounghoon Jeon. “Regulating Drivers’ Aggressiveness by Sonifying Emotional Data” / Wolfgang Hauer, Katharina Vogt. “Sonification of a streaming-server logfile” / Thomas Hermann, Tobias Hildebrandt, Patrick Langeslag, Stefanie Rinderle-Ma. “Optimizing aesthetics and precision in sonification for peripheral process-monitoring” / Minna Huotilainen, Matti Gröhn, Iikka Yli-Kyyny, Jussi Virkkala, Tiina Paunio. “Sleep Enhancement by Sound Stimulation” / Steven Landry, Jayde Croschere, Myounghoon Jeon. “Subjective Assessment of In-Vehicle Auditory Warnings for Rail Grade Crossings” / Rick McIlraith, Paul Walton, Jude Brereton. “The Spatialised Sonification of Drug-Enzyme Interactions” / George Mihalas, Minodora Andor, Sorin Paralescu, Anca Tudor, Adrian Neagu, Lucian Popescu, Antoanela Naaji. “Adding Sound to Medical Data Representation” / Rainer Mittmannsgruber, Katharina Vogt. “Auditory assistance for timing presentations” / Joseph W. Newbold, Andy Hunt, Jude Brereton. “Chemical Spectral Analysis through Sonification” / S. Camille Peres, Daniel Verona, Paul Ritchey. “The Effects of Various Parameter Combinations in Parameter-Mapping Sonifications: A Pilot Study” / Eva Sjuve. “Metopia: Experiencing Complex Environmental Data Through Sound” / Benjamin Stahl, Katharina Vogt. “The Effect of Audiovisual Congruency on Short-Term Memory of Serial Spatial Stimuli: A Pilot Test” / David Worrall. “Realtime sonification and visualisation of network metadata (The NetSon Project)” / Bernhard Zeller, Katharina Vogt. “Auditory graph evolution by the example of spurious correlations” /The compiled collection of extended abstracts included in the ICAD 2015 Proceedings. Extended abstracts include, but are not limited to, late-breaking results, works in early stages of progress, novel methodologies, unique or controversial theoretical positions, and discussions of unsuccessful research or null findings

Data Sonification in Creative Practice

Sonification is the process of data transmission with non-speech audio. While finding increasing acceptance as a scientific method, particularly where a visual representation of data is inadequate, it is still often derided as a ‘gimmick’. Composers have also shown growing interest in sonification as a compositional method. Both in science and in music, the criticism towards this method relates to poor aesthetics and gratuitous applications. This thesis aims to address these issues through an accompanying portfolio of pieces which use sonification as a compositional tool. It establishes the principles of ‘musification’, which can be defined as a sonification which uses musical structures; a sonification organised by musical principles. The practice-as-research portfolio explores a number of data sources, musical genres and science-music collaborations. The main contributions to knowledge derived from the project are a portfolio of compositions, a compositional framework for sonification and an evaluation framework for musification. This thesis demonstrates the validity of practice-as-research as a methodology in sonification research

Digital workflows for the management of existing structures in the pre- and post-earthquake phases: BIM, CDE, drones, laser-scanning and AI

La metodologia BIM, sviluppata in America negli anni '70, ha rivoluzionato l'industria delle costruzioni introducendo i principi di innovazione e digitalizzazione per la gestione dei progetti, in un settore settore produttivo troppo legato a logiche tradizionali. I numerosi processi digitali che sono stati sviluppati da allora hanno riguardato in gran parte la progettazione di nuovi edifici, e sono principalmente legati alla disciplina del construction management. Alcune prime sperimentazioni condotte nel tempo hanno mostrato come l'estensione di questa metodologia agli edifici esistenti comporti molte difficoltà. In questo panorama, il lavoro di tesi si concentra sulla gestione delle strutture nella fase pre e post-sisma con l'obiettivo di sviluppare processi digitali basati sull'uso di tecnologie innovative applicate sia agli edifici ordinari che a quelli storici. Il primo workflow sviluppato, relativo alla fase pre-sisma, è stato denominato scan-to-FEM, ed è finalizzato a particolarizzare il classico processo scan-to-BIM nel campo dell'ingegneria strutturale, analizzando così tutti i passaggi dal rilievo dell'edificio con le tecniche digitali di fotogrammetria e laser-scanning fino all'analisi strutturale e alla valutazione della sicurezza nei confronti delle azioni sismiche. I processi di gestione delle strutture post-sisma sono invece incentrati sulla stima della sicurezza della struttura e sulla definizione delle strategie di intervento, e si basano sull'analisi delle caratteristiche intrinseche della struttura e dei danni indotti dagli eventi sismici. L'intero processo di valutazione del livello operativo di un edificio è stato quindi rivisto alla luce delle moderne tecnologie digitali. Nel dettaglio, sono state sviluppate Reti Neurali Convoluzionali (CNN) per la crack detection, e l'estrazione delle informazioni numeriche associate alle lesioni, gestite poi grazie ai modelli BIM. I quadri fessurativi sono stati digitalizzati grazie allìintroduzione un nuovo oggetto BIM "lesione" (attualmente non codificato nello standard IFC), al quale è stato aggiunto un set di parametri in parte valutati con le CNN ed in parte qualitativi. Durante lo sviluppo di questi processi, sono stati sviluppati nuovi strumenti adhoc per la gestione degli edifici esistenti. In particolare, sono state definite specifiche per lo sviluppo di schede tecniche digitali dei danni, e per la creazione del nuovo oggetto BIM "lesione". I processi di gestione degli edifici danneggiati, grazie agli sviluppi tecnologici realizzati, sono stati applicati per la digitalizzazione dell'edificio storico della chiesa di San Pietro in Vinculis danneggiato a seguito di eventi sismici, grazie ai quali sono stati sperimentati i massimi benefici in termini di riduzione di tempo e risparmio di risorse

Potential fields data modeling: new frontiers in forward and inverse problems

Since the '50, potential fields data modeling has played an important role in analyzing the density and magnetization distribution in Earth's subsurface for a wide variety of applications. Examples are the characterization of ore deposits and the assessment of geothermal and petroleum potential, which turned out to be key contributors for the economic and industrial development after World War II. Current modeling methods mainly rely on two popular parameterization approaches, either involving a discretization of target geological bodies by means of 2D to 2.75D horizontal prisms with polygonal vertical cross-section (polygon-based approach) or prismatic cells (prism-based approach). Despite the great endeavour made by scientists in recent decades, inversion methods based on these parameterization approaches still suffers from a limited ability to (i) realistically characterize the variability of density and magnetization expected in a study area and (ii) take into account the strong non-uniqueness affecting potential fields theory. The prism-based approach is used in linear deterministic inverse methods, which provide just one single solution, preventing uncertainty estimation and statistical analysis on the parameters we would like to characterize (i.e, density or magnetization). On the contrary, the polygon-based approach is almost exclusively exploited in a trial-and-error modeling strategy, leaving the potential to develop innovative inverse methods untapped. The reason is two-fold, namely (i) its strongly non-linear forward problem requires an efficient probabilistic inverse modeling methodology to solve the related inverse problem, and (ii) unpredictable cross-intersections between polygonal bodies during inversion represent a challenging task to be tackled in order to achieve geologically plausible model solutions. The goal of this thesis is then to contribute to solving the critical issues outlined above, developing probabilistic inversion methodologies based on the polygon- and prism-based parameterization approaches aiming to help improving our capability to unravel the structure of the subsurface. Regarding the polygon-based parameterization strategy, at first a deep review of its mathematical framework has been performed, allowing us (i) to restore the validity of a recently criticized mathematical formulation for the 2D magnetic case, and (ii) to find an error sign in the derivation for the 2.75D magnetic case causing potentially wrong numerical results. Such preliminary phase allowed us to develop a methodology to independently or jointly invert gravity and magnetic data exploiting the Hamilton Monte Carlo approach, thanks to which collection of models allow researchers to appraise different geological scenarios and fully characterize uncertainties on the model parameters. Geological plausibility of results is ensured by automatic checks on the geometries of modelled bodies, which avoid unrealistic cross-intersections among them. Regarding the prism-based parameterization approach, the linear inversion method based on the probabilistic approach considers a discretization of target geological scenarios by prismatic bodies, arranged horizontally to cover it and finitely extended in the vertical direction, particularly suitable to model density and magnetization variability inside strata. Its strengths have been proven, for the magnetic case, in the characterization of the magnetization variability expected for the shallower volcanic unit of the Mt. Melbourne Volcanic Field (Northern Victoria Land, Antarctica), helping significantly us to unravel its poorly known inner geophysical architecture

Model Validation and Simulation

The Bauhaus Summer School series provides an international forum for an exchange of methods and skills related to the interaction between different disciplines of modern engineering science. The 2012 civil engineering course was held in August over two weeks at Bauhaus-Universität Weimar. The overall aim was the exchange of research and modern scientific approaches in the field of model validation and simulation between well-known experts acting as lecturers and active students. Besides these educational intentions the social and cultural component of the meeting has been in the focus. 48 graduate and doctoral students from 20 different countries and 22 lecturers from 12 countries attended this summer school. Among other aspects, this activity can be considered successful as it raised the sensitivity towards both the significance of research in civil engineering and the role of intercultural exchange. This volume summarizes and publishes some of the results: abstracts of key note papers presented by the experts and selected student research works. The overview reflects the quality of this summer school. Furthermore the individual contributions confirm that for active students this event has been a research forum and a special opportunity to learn from the experiences of the researchers in terms of methodology and strategies for research implementation in their current work

Seismic Assessment of Geothermal Potential - Concept and ApplicationCase Study of the German Continental Deep Drilling Site (KTB)

Geothermal reservoirs can embody safe, accessible and stable sources of renewable and environmentally friendly energy. In order to access and extract this energy, drilling of deep wells connected with vast financial investments is unavoidable. Thorough predrilling exploration followed by simulations of heat extraction can help to assess the site’s geothermal energy potential and thus lower the risk of possible financial losses. Extraction of heat enclosed in the deep rock can be simulated with a two-well geothermal system. Through one of the wells cool water is being injected into the reservoir, where it is heating up while travelling towards the production well. If certain conditions are fulfilled, water pumped to the surface carries the amount of energy sufficient for geothermal power production. With simulations of such geothermal systems it is possible to predict their profitability and sustainability. The extensive amount of scientific experiments performed during the Continental Deep Drilling Program (KTB) within the years 1985-1996 yielded a wide database of miscellaneous information concerning the continental crystalline crust. This and the fact that temperatures up to 265°C were measured in the KTB drill hole were the motives to choose the KTB site as case study representative for geothermal reservoirs located in crystalline environments.Geothermische Reservoire verkörpern Quellen erneuerbarer, sicherer und jahreszeitenunabhängiger Energie. Um diese Energie zu erreichen ist das Abteufen von tiefen Bohrlöchern unvermeidlich, was jedoch mit erheblichen finanziellen Kosten verbunden ist. Sorgfältige geophysikalische Untersuchungen und anschließende Simulationen der Wärmegewinnung können bei der Beurteilung des geothermischen Potentials der Lokation behilflich sein und somit das Risiko finanzieller Verluste senken. Extraktion von Wärme aus dem tiefen Gestein kann mit Hilfe geohydrothermaler Dubletten simuliert werden. Durch eine der Bohrungen wird das kühle Wasser in das Reservoir eingeführt, wo es sich auf dem Weg zum dem Produktions-Bohrloch erhitzt. Sind bestimmte Vorausetzungen erfüllt, kann das zur Oberfläche gepumpte Wasser eine ausreichende Menge an Energie zur geothermischen Stromerzeugung mit sich führen. Mit Simulationen solcher Geothermieanlagen ist es möglich ihre Rentabilität und Nachhaltigkeit vorherzusagen. Die zahlreichen wissenschaftlichen Experimente, die innerhalb des Projektes der Kontinentalen Tiefbohrung (KTB) in den Jahren 1985-1996 durchgeführt wurden, ergaben eine umfangreiche Datenbank. Dies und die Tatsache, dass Temperaturen bis zu 265°C in dem KTB Bohrloch gemessen wurden, waren die Beweggründe die KTB Lokation repräsentativ für geothermische Reservoire in kristallinem Gestein zu wählen

Automatic feature detection and interpretation in borehole data

Detailed characterisation of the structure of subsurface fractures is greatly facilitated by digital borehole logging instruments, however, the interpretation of which is typically time-consuming and labour-intensive. Despite recent advances towards autonomy and automation, the final interpretation remains heavily dependent on the skill, experience, alertness and consistency of a human operator. Existing computational tools fail to detect layers between rocks that do not exhibit distinct fracture boundaries, and often struggle characterising cross-cutting layers and partial fractures. This research proposes a novel approach to the characterisation of planar rock discontinuities from digital images of borehole logs by using visual texture segmentation and pattern recognition techniques with an iterative adaptation of the Hough transform. This approach has successfully detected non-distinct, partial, distorted and steep fractures and layers in a fully automated fashion and at a relatively low computational cost. Borehole geometry or breakouts (e.g.borehole wall elongation or compression) and imaging tool decentralisation problem affect fracture characterisation and the quality of extracted geological parameters. This research presents a novel approach to the characterisation of distorted fracture in deformed borehole geometry by using least square ellipse fitting and modified Hough transform. This approach approach has successfully detected distorted fractures in deformed borehole geometry using simulated data. To increase the fracture detection accuracy, this research uses multi-sensor data combination by combining extracted edges from different borehole data. This approach has successfully increased true positive detection rate. Performance of the developed algorithms and the results of their application have been promising in terms of speed, accuracy and consistency when compared to manual interpretation by an expert operator. It is highly anticipated that the findings of this research will increase significantly the reliance on automatic interpretation