Methods for Detection and Correction of Sudden Pixel Sensitivity Drops

PDC 8.0 includes implementation of a new algorithm to detect and correct step discontinuities appearing in roughly one of every twenty stellar light curves during a given quarter. An example of such a discontinuity in an actual light curve is shown in fig. 1. The majority of such discontinuities are believed to result from high-energy particles (either cosmic or solar in origin) striking the photometer and causing permanent local changes (typically -0.5% in summed apertures) in quantum efficiency, though a partial exponential recovery is often observed. Since these features, dubbed sudden pixel sensitivity dropouts (SPSDs), are uncorrelated across targets they cannot be properly accounted for by the current detrending algorithm. PDC de-trending is based on the assumption that features in flux time series are due either to intrinsic stellar phenomena or to systematic errors and that systematics will exhibit measurable correlations across targets. SPSD events violate these assumptions and their successful removal not only rectifies the flux values of affected targets, but demonstrably improves the overall performance of PDC de-trending

System of System Integration for Hyperspectral Imaging Microscopy

Hyperspectral imaging (HSI) has become a leading tool in the medical field due to its capabilities for providing assessments of tissue pathology and separation of fluorescence signals. Acquisition speeds have been slow due to the need to acquire signal in many spectral bands and the light losses associated with technologies of spectral filtering. Traditional methods resulted in limited signal strength which placed limitations on time sensitive and photosensitive assays. For example, the distribution of cyclic adenosine monophosphate (cAMP) is largely undetermined because current microscope technologies lack the combination of speed, resolution, and spectral ability to accurately measure Forster resonance energy transfer (FRET). The work presented in this dissertation assesses the feasibility of integrating excitation-scanning hyperspectral imaging methods in widefield and confocal microscopy as a potential solution to improving acquisition speeds without compromising sensitivity and specificity. Our laboratory has previously proposed excitation-scanning approaches to improve signal-to-noise ratio (SNR) and showed that by using excitation-scanning, most-to-all emitted light at each excitation wavelength band can be detected which in turn, increases the SNR. This dissertation describes development and early feasibility studies for two novel prototype concepts as an alternative excitation-scanning HSI technology that may xvi increase acquisition speeds without compromising sensitivity or specificity. To achieve this, two new technologies for excitation-scanning HSI were conceptually designed: - LED-based spectral illumination for widefield microscopy - Supercontinuum-laser-based spectral illumination for spinning disk confocal microscopy. Next, design concepts were theoretically evaluated and optimized, leading to prototype testing. To evaluate the performance of each concept, prototype systems were integrated with other systems and subsystems, calibrated and feasibility assays were executed. This dissertation is divided into three main sections: 1) early development feasibility results of an excitation-scanning widefield system of systems prototype utilizing LED-based HSI, 2) Excitation-scanning HSI and image analysis methods used for endmember identification in fluorescence microscopy studies, and 3) early development feasibility of an excitation-scanning confocal SoS prototype utilizing a supercontinuum laser light source. Integration and testing results proved initial feasibility of both LED-based and broadband-based SoSs. The LED-based light source was successfully tested on a widefield microscope, while the broadband light source system was successfully tested on a confocal microscope. Feasibility for the LED-based system showed that further optical transmission optimization is needed to achieve high acquisition rates without compromising sensitivity or specificity. Early feasibility study results for the broadband-based system showed a successful proof of concept. Findings presented in this dissertation are expected to impact the fields of cellular physiology, medical sciences, and clinical diagnostics by providing the ability for high speed, high sensitivity microscopic imaging with spectroscopic discrimination

Thermal-Aware Networked Many-Core Systems

Advancements in IC processing technology has led to the innovation and growth happening in the consumer electronics sector and the evolution of the IT infrastructure supporting this exponential growth. One of the most difficult obstacles to this growth is the removal of large amount of heatgenerated by the processing and communicating nodes on the system. The scaling down of technology and the increase in power density is posing a direct and consequential effect on the rise in temperature. This has resulted in the increase in cooling budgets, and affects both the life-time reliability and performance of the system. Hence, reducing on-chip temperatures has become a major design concern for modern microprocessors. This dissertation addresses the thermal challenges at different levels for both 2D planer and 3D stacked systems. It proposes a self-timed thermal monitoring strategy based on the liberal use of on-chip thermal sensors. This makes use of noise variation tolerant and leakage current based thermal sensing for monitoring purposes. In order to study thermal management issues from early design stages, accurate thermal modeling and analysis at design time is essential. In this regard, spatial temperature profile of the global Cu nanowire for on-chip interconnects has been analyzed. It presents a 3D thermal model of a multicore system in order to investigate the effects of hotspots and the placement of silicon die layers, on the thermal performance of a modern ip-chip package. For a 3D stacked system, the primary design goal is to maximise the performance within the given power and thermal envelopes. Hence, a thermally efficient routing strategy for 3D NoC-Bus hybrid architectures has been proposed to mitigate on-chip temperatures by herding most of the switching activity to the die which is closer to heat sink. Finally, an exploration of various thermal-aware placement approaches for both the 2D and 3D stacked systems has been presented. Various thermal models have been developed and thermal control metrics have been extracted. An efficient thermal-aware application mapping algorithm for a 2D NoC has been presented. It has been shown that the proposed mapping algorithm reduces the effective area reeling under high temperatures when compared to the state of the art.Siirretty Doriast

Vérification efficace de systèmes à compteurs à l'aide de relaxations

Abstract : Counter systems are popular models used to reason about systems in various fields such as the analysis of concurrent or distributed programs and the discovery and verification of business processes. We study well-established problems on various classes of counter systems. This thesis focusses on three particular systems, namely Petri nets, which are a type of model for discrete systems with concurrent and sequential events, workflow nets, which form a subclass of Petri nets that is suited for modelling and reasoning about business processes, and continuous one-counter automata, a novel model that combines continuous semantics with one-counter automata. For Petri nets, we focus on reachability and coverability properties. We utilize directed search algorithms, using relaxations of Petri nets as heuristics, to obtain novel semi-decision algorithms for reachability and coverability, and positively evaluate a prototype implementation. For workflow nets, we focus on the problem of soundness, a well-established correctness notion for such nets. We precisely characterize the previously widely-open complexity of three variants of soundness. Based on our insights, we develop techniques to verify soundness in practice, based on reachability relaxation of Petri nets. Lastly, we introduce the novel model of continuous one-counter automata. This model is a natural variant of one-counter automata, which allows reasoning in a hybrid manner combining continuous and discrete elements. We characterize the exact complexity of the reachability problem in several variants of the model.Les systèmes à compteurs sont des modèles utilisés afin de raisonner sur les systèmes de divers domaines tels l’analyse de programmes concurrents ou distribués, et la découverte et la vérification de systèmes d’affaires. Nous étudions des problèmes bien établis de différentes classes de systèmes à compteurs. Cette thèse se penche sur trois systèmes particuliers : les réseaux de Petri, qui sont un type de modèle pour les systèmes discrets à événements concurrents et séquentiels ; les « réseaux de processus », qui forment une sous-classe des réseaux de Petri adaptée à la modélisation et au raisonnement des processus d’affaires ; les automates continus à un compteur, un nouveau modèle qui combine une sémantique continue à celles des automates à un compteur. Pour les réseaux de Petri, nous nous concentrons sur les propriétés d’accessibilité et de couverture. Nous utilisons des algorithmes de parcours de graphes, avec des relaxations de réseaux de Petri comme heuristiques, afin d’obtenir de nouveaux algorithmes de semi-décision pour l’accessibilité et la couverture, et nous évaluons positivement un prototype. Pour les «réseaux de processus», nous nous concentrons sur le problème de validité, une notion de correction bien établie pour ces réseaux. Nous caractérisions précisément la complexité calculatoire jusqu’ici largement ouverte de trois variantes du problème de validité. En nous basant sur nos résultats, nous développons des techniques pour vérifier la validité en pratique, à l’aide de relaxations d’accessibilité dans les réseaux de Petri. Enfin, nous introduisons le nouveau modèle d’automates continus à un compteur. Ce modèle est une variante naturelle des automates à un compteur, qui permet de raisonner de manière hybride en combinant des éléments continus et discrets. Nous caractérisons la complexité exacte du problème d’accessibilité dans plusieurs variantes du modèle

Diffeomorphic Transformations for Time Series Analysis: An Efficient Approach to Nonlinear Warping

The proliferation and ubiquity of temporal data across many disciplines has sparked interest for similarity, classification and clustering methods specifically designed to handle time series data. A core issue when dealing with time series is determining their pairwise similarity, i.e., the degree to which a given time series resembles another. Traditional distance measures such as the Euclidean are not well-suited due to the time-dependent nature of the data. Elastic metrics such as dynamic time warping (DTW) offer a promising approach, but are limited by their computational complexity, non-differentiability and sensitivity to noise and outliers. This thesis proposes novel elastic alignment methods that use parametric \& diffeomorphic warping transformations as a means of overcoming the shortcomings of DTW-based metrics. The proposed method is differentiable \& invertible, well-suited for deep learning architectures, robust to noise and outliers, computationally efficient, and is expressive and flexible enough to capture complex patterns. Furthermore, a closed-form solution was developed for the gradient of these diffeomorphic transformations, which allows an efficient search in the parameter space, leading to better solutions at convergence. Leveraging the benefits of these closed-form diffeomorphic transformations, this thesis proposes a suite of advancements that include: (a) an enhanced temporal transformer network for time series alignment and averaging, (b) a deep-learning based time series classification model to simultaneously align and classify signals with high accuracy, (c) an incremental time series clustering algorithm that is warping-invariant, scalable and can operate under limited computational and time resources, and finally, (d) a normalizing flow model that enhances the flexibility of affine transformations in coupling and autoregressive layers.Comment: PhD Thesis, defended at the University of Navarra on July 17, 2023. 277 pages, 8 chapters, 1 appendi

NASA Space Engineering Research Center Symposium on VLSI Design

The NASA Space Engineering Research Center (SERC) is proud to offer, at its second symposium on VLSI design, presentations by an outstanding set of individuals from national laboratories and the electronics industry. These featured speakers share insights into next generation advances that will serve as a basis for future VLSI design. Questions of reliability in the space environment along with new directions in CAD and design are addressed by the featured speakers

Using MTP measurements to characterise atmospheric gravity waves in the tropopause region

Atmosphärische Schwerewellen, die nahe am Erdboden angeregt werden, können weit in die Atmosphäre propagieren. Wenn sie brechen, übertragen sie ihre Energie und ihren Impuls an die Hintergrundströmung und treiben damit die globale Zirkulation der mittleren Atmosphäre. Um das Verständnis über die Entstehung und Ausbreitung von Schwerewellen durch die Atmosphäre weiter zu vergrößern, werden u.a. Messkampagnen mit Forschungsflugzeugen durchgeführt, bei denen besonders die Tropopausen-Region im Fokus steht. Diese ist als Barriere für die Ausbreitung von Schwerewellen in größere Höhen bekannt. Mit Hilfe eines passiven Mikrowellenradiometers, dem Microwave Temperature Profiler (MTP), können vom Flugzeug aus Temperaturmessungen sowohl ober- als auch unterhalb der aktuellen Flughöhe gemacht werden. Da atmosphärische Schwerewellen Temperaturschwankungen hervorrufen, bieten die Messungen des MTP eine gute Möglichkeit Schwerewellen direkt messen und charakterisieren zu können. In der folgenden Arbeit wird untersucht, welche Temperaturfluktuationen vom MTP erfasst werden können und wie gut die Eigenschaften von Schwerewellen, wie ihre horizontale und vertikale Wellenzahl und die intrinsische Frequenz, aus den Temperaturdaten des MTP abgeleitet werden können. Hierzu wird eine Kalibrationsmessung im Labor ausgewertet, um die Detektionsgrenze für Temperaturstörungen festlegen zu können. Des Weiteren wird mit Hilfe von Strahlungstransportsimulationen bestimmt, über welchen Bereich der Atmosphäre Informationen in den MTP-Daten enthalten sind. Es wird gezeigt, dass das MTP atmosphärische Temperaturen mit einer Präzision von 0,37 K messen kann, und eine Analyse von Welleneigenschaften für Temperaturfluktuationen von mindestens 1,5 K Amplitude möglich ist. Das MTP kann über einen Bereich von 2-3 km um die Flughöhe Informationen über die potentielle Temperatur, die Stabilität der Schichtung der Luftmassen, sowie dort auftretende Wellen sammeln. Um Schwerewellen charakterisieren zu können, wurde ein neuer Algorithmus zur Auswertung der aus den MTP-Daten abgeleiteten Tempeaturprofilen entwickelt. In dieser Arbeit wird der Algorithmus vorgestellt und seine Kapazitäten in der Erkennung von Wellen-Eigenschaften in MTP-Daten in einer Studie mit synthetischen Daten getestet. Es wird gezeigt, dass die vertikale Wellenlänge und intrinsische Frequenz mit einer Unsicherheit von maximal 30 % bestimmt werden können. Mit Hilfe von MTP-Daten ist es damit möglich, die Bedingungen für Wellen-Ausbreitung innerhalb der Tropopausen-Region zu bewerten. Schließlich wird der neue Algorithmus benutzt, um Messdaten der DEEPWAVEKampagne, die 2014 in Neuseeland stattfand, auszuwerten. Hier zeigt die Auswertung der MTP-Daten, dass auf Flug-Niveau gemessene Impulsflüsse nicht immer bis zur Stratosphäre gelangen. Die Messungen des MTP bieten einen einzigartigen und wichtigen Einblick in die vorherrschenden Bedingungen für Wellenausbreitung durch die Tropopausenregion.Atmospheric gravity waves, which have sources close to the Earth’s surface, can propagate deep into the atmosphere. When these waves break, the energy and momentum they carry is transferred to the background wind. Thus, they drive the global circulation within the middle atmosphere. As one approach to enhance the understanding of the source processes and the propagation of gravity waves through the atmosphere, measurement campaigns with research aircraft have been conducted, which focus on the troposphere region. This region is known to be a barrier for propagation of gravity waves into higher altitudes. With the help of a passive microwave radiometer, the Microwave Temperature Profiler (MTP), measurements of temperature, both, above and below the aircraft can be conducted. As atmospheric gravity waves cause temperature fluctuations, the MTP provides the possibility to directly measure and characterise gravity waves. In the following thesis it will be assessed, which temperature fluctuation signals can be resolved by the MTP instrument and how well characteristics of gravity waves, such as their horizontal and vertical wavenumbers and the intrinsic frequency, can be derived. Calibration measurements in a laboratory will be analysed to define the lower threshold of detectable temperature fluctuation amplitudes. Moreover, radiative transfer calculations will be carried out to investigate which part of the atmosphere the MTP measurements are sensitive to. It will be shown that the MTP is able to measure atmospheric temperatures with a precision of 0:37 K, and that an analysis of wave characteristics is possible from temperature fluctuations with amplitudes of at least 1:5 K. The MTP is sensitive to a vertical altitude region of 2-3 km around the research aircraft, and is able to collect information on the potential temperatures and static stability of the air masses surrounding the aircraft, as well as on gravity waves within this region. To characterise the gravity waves, a new algorithm for further analysis of the temperature profiles derived from MTP measurements has been developed. This algorithm will be described within this thesis and its capabilities of detecting wave characteristics will be tested in a synthetic data study. It will be shown, that the vertical wavelengths and intrinsic frequencies can be derived with a maximum uncertainty of 30 %. Hence, through the use of MTP data, it is possible to assess propagation conditions for gravity waves within the tropopause region. Finally, the algorithm will be used to evaluate measurements from the DEEPWAVE campaign, which took place in New Zealand in 2014. For these data, the analysis shows that momentum fluxes derived from flight-level measurements, do not always reach the stratosphere. The measurements by the MTP instrument provide a unique and important insight to the prevailing conditions of wave propagation through the tropopause region

UTB/TSC Undergraduate Catalog 2007-2008

https://scholarworks.utrgv.edu/brownsvillelegacycatalogs/1033/thumbnail.jp

Image 100 procedures manual development: Applications system library definition and Image 100 software definition

An outline for an Image 100 procedures manual for Earth Resources Program image analysis was developed which sets forth guidelines that provide a basis for the preparation and updating of an Image 100 Procedures Manual. The scope of the outline was limited to definition of general features of a procedures manual together with special features of an interactive system. Computer programs were identified which should be implemented as part of an applications oriented library for the system