Visuelle Analyse großer Partikeldaten

Partikelsimulationen sind eine bewährte und weit verbreitete numerische Methode in der Forschung und Technik. Beispielsweise werden Partikelsimulationen zur Erforschung der Kraftstoffzerstäubung in Flugzeugturbinen eingesetzt. Auch die Entstehung des Universums wird durch die Simulation von dunkler Materiepartikeln untersucht. Die hierbei produzierten Datenmengen sind immens. So enthalten aktuelle Simulationen Billionen von Partikeln, die sich über die Zeit bewegen und miteinander interagieren. Die Visualisierung bietet ein großes Potenzial zur Exploration, Validation und Analyse wissenschaftlicher Datensätze sowie der zugrundeliegenden Modelle. Allerdings liegt der Fokus meist auf strukturierten Daten mit einer regulären Topologie. Im Gegensatz hierzu bewegen sich Partikel frei durch Raum und Zeit. Diese Betrachtungsweise ist aus der Physik als das lagrange Bezugssystem bekannt. Zwar können Partikel aus dem lagrangen in ein reguläres eulersches Bezugssystem, wie beispielsweise in ein uniformes Gitter, konvertiert werden. Dies ist bei einer großen Menge an Partikeln jedoch mit einem erheblichen Aufwand verbunden. Darüber hinaus führt diese Konversion meist zu einem Verlust der Präzision bei gleichzeitig erhöhtem Speicherverbrauch. Im Rahmen dieser Dissertation werde ich neue Visualisierungstechniken erforschen, welche speziell auf der lagrangen Sichtweise basieren. Diese ermöglichen eine effiziente und effektive visuelle Analyse großer Partikeldaten

LSST Science Book, Version 2.0

A survey that can cover the sky in optical bands over wide fields to faint magnitudes with a fast cadence will enable many of the exciting science opportunities of the next decade. The Large Synoptic Survey Telescope (LSST) will have an effective aperture of 6.7 meters and an imaging camera with field of view of 9.6 deg^2, and will be devoted to a ten-year imaging survey over 20,000 deg^2 south of +15 deg. Each pointing will be imaged 2000 times with fifteen second exposures in six broad bands from 0.35 to 1.1 microns, to a total point-source depth of r~27.5. The LSST Science Book describes the basic parameters of the LSST hardware, software, and observing plans. The book discusses educational and outreach opportunities, then goes on to describe a broad range of science that LSST will revolutionize: mapping the inner and outer Solar System, stellar populations in the Milky Way and nearby galaxies, the structure of the Milky Way disk and halo and other objects in the Local Volume, transient and variable objects both at low and high redshift, and the properties of normal and active galaxies at low and high redshift. It then turns to far-field cosmological topics, exploring properties of supernovae to z~1, strong and weak lensing, the large-scale distribution of galaxies and baryon oscillations, and how these different probes may be combined to constrain cosmological models and the physics of dark energy.Comment: 596 pages. Also available at full resolution at http://www.lsst.org/lsst/sciboo

Electron Beam X-Ray Computed Tomography for Multiphase Flows and An Experimental Study of Inter-channel Mixing

This thesis consists of two parts. In the first, a high speed X-ray Computed Tomography (CT) system for multiphase flows is developed. X-ray Computed Tomography (CT) has been employed in the study of multiphase flows. The systems developed to date often have excellent spatial resolution at the expense of poor temporal resolution. Hence, X-ray CT has mostly been employed to examining time averaged phase distributions. In the present work, we report on the development of a Scanning Electron Beam X-ray Tomography (SEBXT) CT system that will allow for much higher time resolution with acceptable spatial resolution. The designed system, however, can have issues such as beam-hardening and limited angle artifacts. In the present study, we developed a high speed, limited angle SEBXT system along with a new CT reconstruction algorithm designed to enhance the CT reconstruction results of such system. To test the performance of the CT system, we produced example CT reconstruction results for two test phantoms based on the actual measured sinograms and the simulated sinograms. The second part examines, the process by which fluid mixes between two parallel flow channels through a narrow gap. This flow is a canonical representation of the mixing and mass transfer processes that often occur in thermo-hydraulic systems. The mixing can be strongly related to the presence of large-scale periodic flow structures that form within the gap. In the present work, we have developed an experimental setup to examine the single-phase mixing through the narrow rectangular gaps connecting two rectangular channels. Our goal is to elucidate the underlying flow processes responsible for inter-channel mixing, and to produce high-fidelity data for validation of computational models. Dye concentration measurements were used to determine the time average rate of mixing. Particle Imaging Velocimetry (PIV) was used to measure the flow fields within the gap. A Proper Orthogonal Decomposition (POD) of the PIV flow fields revealed the presence of coherent flow structure. The decomposed flow fields were then used to predict the time averaged mixing, which closely matched the experimentally measured values.PHDNaval Architecture & Marine EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/138666/1/seongjin_2.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138666/2/seongjin_1.pd

Software Development and Detector Characterization of the EUCLID Near-Infrared Spectro-Photometer

The Euclid space mission, approved by the European Space Agency, is planned to perform an extensive survey over a 6 years period, beginning end of 2020. The satellite will be equipped with two instruments, a visible imager and a near-infrared spectro-photometer (NISP). These instruments will allow to measure the shape and redshift of galaxies over a large fraction of the extragalactic sky in order to study the evolution of cosmic structures, the accelerated expansion of the Universe and the nature of dark matter. This thesis has been carried out in the context of the INFN team participating in Euclid. I have contributed to the development of a software simulating the Euclid Spacecraft commanding and responding towards the NISP Instrument Control Unit. By this simulator the testing and validation of the functionalities of the Control Unit Application Software are made possible. My PhD activity abroad (6 months) was done at the CPPM Lab in Marseille collaborating with the local group in charge of the characterization of NISP infrared detectors. I took part in data acquisition shifts during calibration campaigns and I carried out an analysis on infrared detector dark current's dependence on temperature. By this analysis it was proved that the dark current of infrared detectors is compliant with Euclid requirements and that its behaviour in the range of Euclid operation temperatures is well understood

Black holes and how to find them : on the detection of compact objects at several scales

This dissertation is structured in four chapters. First, the reader is introduced to current detection methods for astrophysical black holes at different scales. The following three chapters correspond to different research projects regarding black hole detection. The second chapter presents the kinematic detection of a supermassive black hole at the center of the dwarf spherical galaxy Leo I. Chapter three presents a novel idea for the detection of supermassive black hole binaries using the effect their gravitational waves produce on lower frequency gravitational waves in our vicinity. Finally, chapter four describes the spectroscopic follow-up of LIGO-Virgo-Kagra gravitational wave sources conducted using the Hobby Eberly Telescope at McDonald Observatory.Physic

Engineering Education and Research Using MATLAB

MATLAB is a software package used primarily in the field of engineering for signal processing, numerical data analysis, modeling, programming, simulation, and computer graphic visualization. In the last few years, it has become widely accepted as an efficient tool, and, therefore, its use has significantly increased in scientific communities and academic institutions. This book consists of 20 chapters presenting research works using MATLAB tools. Chapters include techniques for programming and developing Graphical User Interfaces (GUIs), dynamic systems, electric machines, signal and image processing, power electronics, mixed signal circuits, genetic programming, digital watermarking, control systems, time-series regression modeling, and artificial neural networks

LSST Science Book, Version 2.0

A survey that can cover the sky in optical bands over wide fields to faint magnitudes with a fast cadence will enable many of the exciting science opportunities of the next decade. The Large Synoptic Survey Telescope (LSST) will have an effective aperture of 6.7 meters and an imaging camera with field of view of 9.6 deg^2, and will be devoted to a ten-year imaging survey over 20,000 deg^2 south of +15 deg. Each pointing will be imaged 2000 times with fifteen second exposures in six broad bands from 0.35 to 1.1 microns, to a total point-source depth of r~27.5. The LSST Science Book describes the basic parameters of the LSST hardware, software, and observing plans. The book discusses educational and outreach opportunities, then goes on to describe a broad range of science that LSST will revolutionize: mapping the inner and outer Solar System, stellar populations in the Milky Way and nearby galaxies, the structure of the Milky Way disk and halo and other objects in the Local Volume, transient and variable objects both at low and high redshift, and the properties of normal and active galaxies at low and high redshift. It then turns to far-field cosmological topics, exploring properties of supernovae to z~1, strong and weak lensing, the large-scale distribution of galaxies and baryon oscillations, and how these different probes may be combined to constrain cosmological models and the physics of dark energy

A Herschel Space Observatory View of the Andromeda Galaxy

In this thesis we study the energy balance that sets the structure of the interstellar medium (ISM) phases, which in turn control the processes of star-formation (SF). Understanding the energy balance of the ISM is an essential step towards understanding the processes which shape evolution of galaxies across the cosmic time, and lead to the diversity of galaxy properties in the Universe. This work focuses on M31, an ideal laboratory to study the ISM due to its proximity, external perspective, and as it is a representative of the large, star-forming, metal-rich galaxies where most of the SF in the local Universe occurs. We present the Survey of Lines in M31 (SLIM) with contributing new Integral Field Spectroscopic Herschel [CII] and Calar Alto Halpha data, which allow us to study the dominant neutral gas coolant – [CII] on ~50 pc scales. We combine archival ISO [CII] measurements in the bulge of M31 with ancillary data to identify potential heating sources responsible for gas heating in the absence of young stars. For the first time in extragalactic studies, we directly constrain the ISRF intensity and spectral shape, based on PHAT modelling of the spectral energy distributions (SEDs) and extinction of the individual stars in M31 from the PHAT. We find that a significant amount (~20–90%) of the [CII] emission comes from outside SF regions. We find that the [CII] – SFR correlation holds even at the small scales (~50 pc), although the relation typically has a flatter slope than found at larger ~kpc) scales, where [CII] traces the SFR approximately linearly. The photoelectric (PE) heating mechanism seems as the largest contributor to gas heating (where FUV flux is generated by evolved stellar populations), however photoionization and cosmic rays heating mechanisms are likely to be responsible for the observed [CII] “excess” in the bulge. We also find that the attenuated UV energy relative to the total attenuated energy correlates well with the [CII]/TIR ratio, suggesting that it is the soft photon heating of dust that is driving the variation in the [CII]/TIR ratio across this disk. We propose that a better method to approximate the PE heating efficiency (than [C ii]/TIR) is an estimate of the energy absorbed by dust in the PE heating wavelength range (UVatt), that together with the [CII] emission allows us to determine the “true” PE efficiency [CII]=UVatt. Our preliminary results suggest that the UVatt is generated predominantly by B0–B3 type stars (~60%), and only approximately 30% is coming from O-stars. This means that in M31, SFR tracers such as UV & [C ii] might be dominated by heating generated by stars ~10 Myr old, not only recent SF, which would lead to the overestimate of SFRs

Engineering planetary lasers for interstellar communication

Transmitting large amounts of data efficiently among neighboring stars will vitally support any eventual contact with extrasolar intelligence, whether alien or human. Laser carriers are particularly suitable for high-quality, targeted links. Space laser transmitter systems designed by this work, based on both demonstrated and imminent advanced space technology, could achieve reliable data transfer rates as high as 1 kb/s to matched receivers as far away as 25 pc, a distance including over 700 approximately solar-type stars. The centerpiece of this demonstration study is a fleet of automated spacecraft incorporating adaptive neural-net optical processing active structures, nuclear electric power plants, annular momentum control devices, and ion propulsion. Together the craft sustain, condition, modulate, and direct to stellar targets an infrared laser beam extracted from the natural mesospheric, solar-pumped, stimulated CO2 emission recently discovered at Venus. For a culture already supported by mature interplanetary industry, the cost of building planetary or high-power space laser systems for interstellar communication would be marginal, making such projects relevant for the next human century. Links using high-power lasers might support data transfer rates as high as optical frequencies could ever allow. A nanotechnological society such as we might become would inevitably use 10 to the 20th power b/yr transmission to promote its own evolutionary expansion out of the galaxy