Impact of a Lossy Image Compression on Parameter Estimation with Periodic Active Thermal Imaging.

Periodic thermal imaging is a method of active thermography based on a periodic thermal stimulation of an inspected sample material and the analysis of its thermal response when a steady regime is reached. The original data, a sequence of images sampling the thermal response on a large number of periods, are usually stored in a raw format. For accurate exploitation of these measurements, the whole sequence of images requiresa significant amount of storage space. In this report, we address the question of the lossy compression of these sequences of images when they are applied to perform physical parameter estimation. The study investigates the impact of lossy image compression on the performance of the physical parameter estimation procedure, and shows the possibility of preserving robust estimation with high compression rate. Perspectives and applications are then discussed. Performing good enough estimate of physical parameters with compressed images would permit the use of portable thermal cameras with limited resources in terms of data storage. This would enable the use of periodic active thermal imaging to perform relatively low cost embedded characterization of thermal properties of materials

Imaging the first light: experimental challenges and future perspectives in the observation of the Cosmic Microwave Background Anisotropy

Measurements of the cosmic microwave background (CMB) allow high precision observation of the Last Scattering Surface at redshift $z\sim$1100. After the success of the NASA satellite COBE, that in 1992 provided the first detection of the CMB anisotropy, results from many ground-based and balloon-borne experiments have showed a remarkable consistency between different results and provided quantitative estimates of fundamental cosmological properties. During 2003 the team of the NASA WMAP satellite has released the first improved full-sky maps of the CMB since COBE, leading to a deeper insight into the origin and evolution of the Universe. The ESA satellite Planck, scheduled for launch in 2007, is designed to provide the ultimate measurement of the CMB temperature anisotropy over the full sky, with an accuracy that will be limited only by astrophysical foregrounds, and robust detection of polarisation anisotropy. In this paper we review the experimental challenges in high precision CMB experiments and discuss the future perspectives opened by second and third generation space missions like WMAP and Planck.Comment: To be published in "Recent Research Developments in Astronomy & Astrophysics Astrophysiscs" - Vol I

NASA Tech Briefs, June 2012

Topics covered include: iGlobe Interactive Visualization and Analysis of Spatial Data; Broad-Bandwidth FPGA-Based Digital Polyphase Spectrometer; Small Aircraft Data Distribution System; Earth Science Datacasting v2.0; Algorithm for Compressing Time-Series Data; Onboard Science and Applications Algorithm for Hyperspectral Data Reduction; Sampling Technique for Robust Odorant Detection Based on MIT RealNose Data; Security Data Warehouse Application; Integrated Laser Characterization, Data Acquisition, and Command and Control Test System; Radiation-Hard SpaceWire/Gigabit Ethernet-Compatible Transponder; Hardware Implementation of Lossless Adaptive Compression of Data From a Hyperspectral Imager; High-Voltage, Low-Power BNC Feedthrough Terminator; SpaceCube Mini; Dichroic Filter for Separating W-Band and Ka-Band; Active Mirror Predictive and Requirement Verification Software (AMP-ReVS); Navigation/Prop Software Suite; Personal Computer Transport Analysis Program; Pressure Ratio to Thermal Environments; Probabilistic Fatigue Damage Program (FATIG); ASCENT Program; JPL Genesis and Rapid Intensification Processes (GRIP) Portal; Data::Downloader; Fault Tolerance Middleware for a Multi-Core System; DspaceOgreTerrain 3D Terrain Visualization Tool; Trick Simulation Environment 07; Geometric Reasoning for Automated Planning; Water Detection Based on Color Variation; Single-Layer, All-Metal Patch Antenna Element with Wide Bandwidth; Scanning Laser Infrared Molecular Spectrometer (SLIMS); Next-Generation Microshutter Arrays for Large-Format Imaging and Spectroscopy; Detection of Carbon Monoxide Using Polymer-Composite Films with a Porphyrin-Functionalized Polypyrrole; Enhanced-Adhesion Multiwalled Carbon Nanotubes on Titanium Substrates for Stray Light Control; Three-Dimensional Porous Particles Composed of Curved, Two-Dimensional, Nano-Sized Layers for Li-Ion Batteries 23 Ultra-Lightweight; and Ultra-Lightweight Nanocomposite Foams and Sandwich Structures for Space Structure Applications

Energy localization and heat generation in composite energetic systems under high-frequency mechanical excitation

In this work, the ability to use high frequency mechanical excitation to generate significant heating within plastic bonded explosives, as well as single energetic particles embedded within a viscoelastic binder, is studied. In this work, the fundamental mechanisms associated with the conversion of high-frequency mechanical excitation to heat as applied to these composite energetic systems are thoroughly investigated. High-frequency contact excitation has been used to generate a significant amount of heat within samples of PBX 9501 and representative inert mock materials. Surface temperature rises on the order of 10 °C were observed at certain frequencies over a range from 50 kHz to 40 MHz at thermal steady state conditions. The mechanical responses of these samples were also measured to explore the connection between the thermal and bulk motion of the samples. It was found that significant heating of the samples near the transducer resonance was driven by the bulk motion of the material while heating observed at higher frequencies were attributed to particle-scale interactions. To further investigate the interactions occurring at the particle scale, similar excitation was applied to samples of an elastic binder embedded with individual inert or energetic particles. Samples were excited over a range of 100 kHz to 20 MHz, and two distinct frequency regions were observed with separate characteristic heating trends. Through the comparison of the measured surface motion of the sample to the spatial temperature maps of the surface, it was determined that for heating observed in the samples at excitation frequencies above 1 MHz, the heat generation was due viscoelastic effects of the binder near the sample surface. However, at excitation frequencies near the transducer resonance of 215 kHz, it was determined that significant heat was generated at the inclusion and was associated with particle-binder interactions. For these cases of particle associated heating, an analytical heat conduction model was fit to the collected surface temperature data to estimate the heating rates and temperatures associated with the embedded particles. To investigate the potential of stress concentrations to generate localized heating near an inclusion due to viscoelastic losses, an analytical solution of the stress and temperature fields caused by wave scattering effects due to a spherical inclusion within a lossy binder was developed. Results indicate that under certain excitation and sample configurations, significant heating can occur due to stress concentrations caused by constructive interference of the waves near the inclusion and temperatures are predicted to approach or exceed realistic decomposition temperatures of various energetic materials. This analysis indicates that significant heating of the embedded particles can be induced without the presence of delamination or voids; however, this phenomenon it thought to mainly be a precursor or driver to more dynamic events associated with debonding between the particle and binder. Finally, high speed X-ray phase contrast imaging and high speed visible microscopy were used to demonstrate the individual heating mechanisms associated with the heating and subsequent decomposition of an HMX particle within a viscoelastic binder under ultrasonic excitation. Additional analysis of the transient surface temperature of the sample was used to characterize and quantify the heat generation produced from each observed heating mechanism. The results and developed methods presented in this work should prove useful in the understanding of the conversion of mechanical to thermal energy via various mechanisms within composite energetic systems. (Abstract shortened by ProQuest.

Data Compression for Helioseismology

Die effiziente Kompression von Daten wird eine wichtige Rolle für mehrere bevorste- hende und geplante Weltraummissionen spielen, die Helioseismologie betreiben werden, wie beispielsweise Solar Orbiter. Solar Orbiter ist die nächste Mission, die Helioseismologie beinhaltet, und soll im Oktober 2018 gestartet werden. Das Hauptmerkmal von Solar Orbiter ist der Orbit. Die Umlaufbahn des Satelliten wird zur Ekliptik geneigt sein, sodass der Satellit einen solaren Breitengrad von bis zu 33 Grad erreichen wird. Dies wird erstmals ermöglichen, die Pole der Sonne mit Hilfe von lokaler Helioseismologie zu studieren. Zusätzlich dazu können kombinierte Beobachtungen von Solar Orbiter und einem anderen Instrument dazu benutzt werden, die tiefen Schichten der Sonne mittels stereoskopischer Helioseismologie zu erforschen. Die Aufnahmen der Dopplergeschwindigkeit und der Kontinuumsintensität, die für Helioseismologie benötigt werden, werden vom Polarimetric and Helioseismic Imager (PHI) geliefert werden. Große Hindernisse für Helioseismologie mit Solar Orbiter sind die niedrige Datenüber- tragungsrate und die (wahrscheinlich) kurzen Beobachtungszeiten. Außerdem erfordert die Untersuchung der Pole der Sonne Beobachtungen in der Nähe des Sonnenrandes, sogar von dem geneigten Orbit von Solar Orbiter aus. Dies kann zu systematischen Fehlern führen. In dieser Doktorarbeit gebe ich eine erste Einschätzung ab, wie stark Helioseismologie von verlustbehafteter Datenkompression beeinflusst wird. Mein Schwerpunkt liegt dabei auf der Solar Orbiter Mission, die von mir erzielten Ergebnisse sind aber auch auf andere geplante Missionen übertragbar. Zunächst habe ich mit Hilfe synthetischer Daten die Eignung des PHI Instruments für Helioseismologie getestet. Diese basieren auf Simulationen der Konvektion nahe der Sonnenoberfläche und einem Modell von PHI. Ich habe eine sechs Stunden lange Zeitreihe synthetischer Daten erstellt, die die gleichen Eigenschaften wie die von PHI erwarteten Daten haben. Hierbei habe ich mich auf den Einfluss der Punktspreizfunktion, der Vibrationen des Satelliten und des Photonenrauschen konzentriert. Die von diesen Daten abgeleitete spektrale Leistungsdichte der solaren Oszillationen legt nahe, dass PHI für Helioseismologie geeignet sein wird. Aufgrund der niedrigen Datenübertragungsrate von Solar Orbiter müssen die von PHI für die Helioseismologie gewonnenen Daten stark komprimiert werden. Ich habe den Einfluss von Kompression mit Hilfe von Daten getestet, die vom Helioseismic and Magnetic Imager (HMI) stammen. HMI ist ein Instrument an Bord des Solar Dynam- ics Observatory Satelliten (SDO), der 2010 gestartet worden ist. HMI erstellt mit hoher zeitlicher Abfolge Karten der Kontinuumsintensität, der Dopplergeschwindigkeit und des kompletten Magnetfeldvektors für die komplette von der Erde aus sichtbare Hemispäre der Sonne. Mit Hilfe mit von HMI aufgenommenen Karten der Dopplergeschwindigkeit konnte ich zeigen, dass das Signal-zu-Rausch Verhältnis von Supergranulation in der Zeit-Entfernungs Helioseismologie nicht stark von Datenkompression beeinflusst wird. Außerdem habe ich nachgewiesen, dass die Genauigkeit und Präzision von Messungen der Sonnenrotation mittels Local Correlation Tracking von Granulation durch verlust- behaftete Datenkompression nicht wesentlich verschlechtert werden. Diese Ergebnisse deuten an, dass die niedrige Datenübertragungsrate von Solar Orbiter nicht unbedingt ein großes Hinderniss für Helioseismologie sein muss

Quantum Communication, Sensing and Measurement in Space

The main theme of the conclusions drawn for classical communication systems operating at optical or higher frequencies is that there is a well‐understood performance gain in photon efficiency (bits/photon) and spectral efficiency (bits/s/Hz) by pursuing coherent‐state transmitters (classical ideal laser light) coupled with novel quantum receiver systems operating near the Holevo limit (e.g., joint detection receivers). However, recent research indicates that these receivers will require nonlinear and nonclassical optical processes and components at the receiver. Consequently, the implementation complexity of Holevo‐capacityapproaching receivers is not yet fully ascertained. Nonetheless, because the potential gain is significant (e.g., the projected photon efficiency and data rate of MIT Lincoln Laboratory's Lunar Lasercom Demonstration (LLCD) could be achieved with a factor‐of‐20 reduction in the modulation bandwidth requirement), focused research activities on ground‐receiver architectures that approach the Holevo limit in space‐communication links would be beneficial. The potential gains resulting from quantum‐enhanced sensing systems in space applications have not been laid out as concretely as some of the other areas addressed in our study. In particular, while the study period has produced several interesting high‐risk and high‐payoff avenues of research, more detailed seedlinglevel investigations are required to fully delineate the potential return relative to the state‐of‐the‐art. Two prominent examples are (1) improvements to pointing, acquisition and tracking systems (e.g., for optical communication systems) by way of quantum measurements, and (2) possible weak‐valued measurement techniques to attain high‐accuracy sensing systems for in situ or remote‐sensing instruments. While these concepts are technically sound and have very promising bench‐top demonstrations in a lab environment, they are not mature enough to realistically evaluate their performance in a space‐based application. Therefore, it is recommended that future work follow small focused efforts towards incorporating practical constraints imposed by a space environment. The space platform has been well recognized as a nearly ideal environment for some of the most precise tests of fundamental physics, and the ensuing potential of scientific advances enabled by quantum technologies is evident in our report. For example, an exciting concept that has emerged for gravity‐wave detection is that the intermediate frequency band spanning 0.01 to 10 Hz—which is inaccessible from the ground—could be accessed at unprecedented sensitivity with a space‐based interferometer that uses shorter arms relative to state‐of‐the‐art to keep the diffraction losses low, and employs frequency‐dependent squeezed light to surpass the standard quantum limit sensitivity. This offers the potential to open up a new window into the universe, revealing the behavior of compact astrophysical objects and pulsars. As another set of examples, research accomplishments in the atomic and optics fields in recent years have ushered in a number of novel clocks and sensors that can achieve unprecedented measurement precisions. These emerging technologies promise new possibilities in fundamental physics, examples of which are tests of relativistic gravity theory, universality of free fall, frame‐dragging precession, the gravitational inverse‐square law at micron scale, and new ways of gravitational wave detection with atomic inertial sensors. While the relevant technologies and their discovery potentials have been well demonstrated on the ground, there exists a large gap to space‐based systems. To bridge this gap and to advance fundamental‐physics exploration in space, focused investments that further mature promising technologies, such as space‐based atomic clocks and quantum sensors based on atom‐wave interferometers, are recommended. Bringing a group of experts from diverse technical backgrounds together in a productive interactive environment spurred some unanticipated innovative concepts. One promising concept is the possibility of utilizing a space‐based interferometer as a frequency reference for terrestrial precision measurements. Space‐based gravitational wave detectors depend on extraordinarily low noise in the separation between spacecraft, resulting in an ultra‐stable frequency reference that is several orders of magnitude better than the state of the art of frequency references using terrestrial technology. The next steps in developing this promising new concept are simulations and measurement of atmospheric effects that may limit performance due to non‐reciprocal phase fluctuations. In summary, this report covers a broad spectrum of possible new opportunities in space science, as well as enhancements in the performance of communication and sensing technologies, based on observing, manipulating and exploiting the quantum‐mechanical nature of our universe. In our study we identified a range of exciting new opportunities to capture the revolutionary capabilities resulting from quantum enhancements. We believe that pursuing these opportunities has the potential to positively impact the NASA mission in both the near term and in the long term. In this report we lay out the research and development paths that we believe are necessary to realize these opportunities and capitalize on the gains quantum technologies can offer

High Power Microwave Operational Exposure Detection using Thermoacoustic Wave Generation in Lossy Dielectric Polymers

A feasibility analysis for the use of microwave-induced thermoacoustic (TA) wave generation in lossy dielectric media to detect pulsed high power microwave directed energy weapons in force health protection applications was conducted based on a series of empirical and computational investigations. A potential target volume material, carbon-loaded polytetrafluoroethylene, was identified for further study based on anticipated complex dielectric properties, with laboratory measurements of select electromagnetic (EM), thermal, and elastic material properties of relevance to the TA effect conducted to determine parameter values. A planar geometry TA-based signal chain model using thin film piezoelectric sensors was developed for both finite element method based numerical simulation and in-beam response testing, with TA signal output evaluated in the time and frequency domain using both approaches. Based on empirically-derived complex permittivity values, a single-term Cole-Cole dielectric relaxation model approximation was developed over the 2-110 GHz microwave frequency region to permit a more general evaluation of EM coupling efficiency of the material. Modeling and simulation of the idealized signal chain allowed the analysis of TA waveform dependency on microwave beam parameters not otherwise accessible during in-beam response testing. High frequency TA signal data was suitably fit to a pulse width sensitivity impulse response function model for the target geometry and found to be in good agreement for personnel exposure applications

Active and passive approaches for image authentication

Ph.DDOCTOR OF PHILOSOPH

Wide Band Embedded Slot Antennas for Biomedical, Harsh Environment, and Rescue Applications

For many designers, embedded antenna design is a very challenging task when designing embedded systems. Designing Antennas to given set of specifications is typically tailored to efficiently radiate the energy to free space with a certain radiation pattern and operating frequency range, but its design becomes even harder when embedded in multi-layer environment, being conformal to a surface, or matched to a wide range of loads (environments). In an effort to clarify the design process, we took a closer look at the key considerations for designing an embedded antenna. The design could be geared towards wireless/mobile platforms, wearable antennas, or body area network. Our group at UT has been involved in developing portable and embedded systems for multi-band operation for cell phones or laptops. The design of these antennas addressed single band/narrowband to multiband/wideband operation and provided over 7 bands within the cellular bands (850 MHz to 2 GHz). Typically the challenge is: many applications require ultra wide band operation, or operate at low frequency. Low frequency operation is very challenging if size is a constraint, and there is a need for demonstrating positive antenna gain