Algorithms and Systems for IoT and Edge Computing

The idea of distributing the signal processing along the path that starts with the acquisition and ends with the final application has given light to the Internet of Things and Edge Computing, which have demonstrated several advantages in terms of scalability, costs, and reliability. In this dissertation, we focus on designing and implementing algorithms and systems that allow performing a complex task on devices with limited resources. Firstly, we assess the trade-off between compression and anomaly detection from both a theoretical and a practical point of view. Information theory provides the rate-distortion analysis that is extended to consider how information content is processed for detection purposes. Considering an actual Structural Health Monitoring application, two corner cases are analysed: detection in high distortion based on a feature extraction method and detection with low distortion based on Principal Component Analysis. Secondly, we focus on streaming methods for Subspace Analysis. In this context, we revise and study state-of-the-art methods to target devices with limited computational resources. We also consider a real case of deployment of an algorithm for streaming Principal Component Analysis for signal compression in a Structural Health Monitoring application, discussing the trade-off between the possible implementation strategies. Finally, we focus on an alternative compression framework suited for low-end devices that is Compressed Sensing. We propose a different decoding approach that splits the recovery problem into two stages and effectively adopts a deep neural network and basic linear algebra to reconstruct biomedical signals. This novel approach outperforms the state-of-the-art in terms of quality of reconstruction and requires lower computational resources

Subspace based data-driven designs of fault detection systems

The thesis focuses on advanced methods of fault detection and diagnosis suitable for application in large-scale processes. The theory of fault diagnosis mainly comprises development of mathematical models for observing critical changes in the process under consideration. The so-called residual signal is used for the purpose of detecting abnormal events and diagnosing their nature. For large-scale processes, it is difficult to build their models mathematically. Therefore, very often historical data from regular sensor measurements, event-logs and records are used to directly identify relationship between plant's input and output. On these lines, the thesis presents a data-driven design of fault detection systems which reduces the computation burden by identifying only the key components and not the entire process model itself. The novel design method is also studied within the context of parameter varying systems. Since many processes undergo temporary fluctuation of their crucial parameters, which can not be ruled out as faults, the fault detection system must be able to adapt to these changes. This is realized in the thesis with two efficient algorithms, which are based on recursive identification techniques. The theoretical contribution in this thesis also revolves around improvising the novel data-drive design of fault detection systems. In other words, the identification procedure is optimized by reformulating it as “closed-loop” identification or identification of Kalman filter. Also, the algorithm is numerically optimized by using QR based decomposition technique. The thesis also presents application results of different algorithms derived in this work. As benchmarks, the Tennessee Eastman chemical plant and the continuously stirred tank heater are considered. The novel algorithms are compared with the existing popular techniques from the literature.Die Arbeit konzentriert sich auf fortgeschrittene Methoden zur Fehlererkennung und Diagnose für den Einsatz in Mehrgrößen Systemen. Üblicherweise umfasst die Fehlerdiagnose Entwicklung von mathematischen Modellen zur Beobachtung der Veränderungen in den ursprünglichen Prozessen. Dabei wird ein so genanntes Residuensignal zur von Fehlern benutzt, welches im Fehlerfall einen Ausschlag zeigt. Für Mehrgrößen Systeme, ist es im Allgemeinen schwierig, mathematische Modelle zu erstellen, die mathematisch abgeleitet werden können. Deshalb werden Daten aus dem Prozess, z.B. aus regelmäßigen Messungen, Event-Logs oder Records verwendet, um Beziehungen zwischen Prozess-Eingang und Ausgang abzubilden. Davon ausgehend werden in der vorliegenden Arbeit Verfahren entwickelt um ein Datenbasiertes Fehlererkennungssystem zu generieren, welches ohne Modelidentifikation arbeitet. In dieser Arbeit wird das Problem der Datenbasierten Fehlererkennung weiter im Rahmen der so genannten Parameter Varianten Systeme untersucht. Da viele Prozesse vorübergehenden Parameterschwankungen unterliegen, die nicht als Fehler ausgeschlossen werden können, muss das Fehlererkennung System in der Lage sein, die Veränderungen zu adaptieren. Ein solches lernendes Fehlererkennungssystem ist hier an Hand von zwei effizienten Algorithmen und mit rekursiver Identifikation realisiert. Der Beitrag in dieser Arbeit ist auch ein modifiziertes, optimales Subraum Identifikation basiertes Entwurf. Darüber hinaus wird das Identifikationsverfahren auf die Hauptkomponenten beschränkt und das ursprüngliche Problem wird für die optimale Parameterschätzung als „Closed-Loop“ Identifikation oder Identifikation des Kalman Filters umformuliert. Die gesamte Konstruktion ist numerisch über eine QR Zerlegung numerisch optimiert. Die Arbeit stellt auch Ergebnisse der Applikation verschiedener Algorithmen vor. Als Versuchstand wurden das Tennessee Eastman Prozess und eine kontinuierlich gerührte Tankheizung verwendet. Die Algorithmen dieser Arbeit werden mit dem ursprünglichen und anderen Identifikationsverfahren verglichen

Alternatives for Jet Engine Control. Volume 1: Modelling and Control Design with Jet Engine Data

This document compiles a comprehensive list of publications supported by, or related to, National Aeronautics and Space Administration Grant NSG-3048, entitled "Alternatives for Jet Engine Control". Dr. Kurt Seldner was the original Technical Officer for the grant, at Lewis Research Center. Dr. Bruce Lehtinen was the final Technical Officer. At the University of Notre Dame, Drs. Michael K. Sain and R. Jeffrey Leake were the original Project Directors, with Dr. Sain becoming the final Project Director. Publications cover work over a ten-year period. The Final Report is divided into two parts. Volume i, "Modelling and Control Design with Jet Engine Data", follows in this report. Volume 2, "Modelling and Control Design with Tensors", has been bound separately

A Time-linearized Navier-Stokes Solver for Annular Gas Seal Rotordynamic Analysis

A time-linearized CFD solver for analyzing rotordynamics of gas seals is presented offering an improvement over existing linearized CFD solvers. Previous linearized solvers required structured grids and axisymmetric domains, limiting the complexity of the geometries of the seals that could be analyzed. A preexisting, full-order, in-house CFD solver was available which operated on fully 3D and unstructured grids and was well suited for complex seal geometries. A linearized version of the in-house code is developed as a companion to the full-order solver, retaining its unstructured and fully 3D features. Furthermore, boundary conditions are developed for the linearized solver allowing it to take advantage of the geometric symmetries that were required by earlier linearized solvers without necessarily being limited to them. Additionally, a linearization procedure is presented which is general enough to be used for the many various features of the full-order solver. As the in-house code continues to be developed and new features are included, the same linearization procedure can be used to keep the companion code up to date. The full-order, in-house solver and the time-linearized companion code combine to become a powerful CFD-perturbation solver accessible to all complexities of seal geometries. This dissertation also presents an analytical formula that describes features of cavity flow as it pertains to annular gas seals in order to progress the fundamental understanding of the flow physics of roughened seals. An existing semi-empirical analytical formula, developed to describe the cavity flow of aircraft bomb bays, is modified using the full-order, in-house CFD solver. The numeric model is validated against experimental measurements and used to adjust empirical parameters of the formula to match cavity flow conditions unique to annular seals. The modified analytical formula is able to predict features of cavity flows found in annular gas seals better than existing formulae. Finally, the companion, time-linearized CFD solver is verified using two simple cases and the combined full-order and time-linearized CFD-perturbation solver is used to predict rotordynamic properties for two gas seal geometries. The first case used to verify the linearized solver is a channel flow with an oscillating back-pressure and the second is a stationary flow with an oscillating wall. The first gas seal case the combined CFD-perturbation solver is used for is a straight seal based on the High Pressure Oxidizer Turbopump (HPOTP) of the Space Shuttle Main Engine (SSME). The second is a stepped labyrinth seal. The rotordynamic predictions are compared with established bulk-flow models of the two cases and conclusions are presented

Aeronautical engineering: A continuing bibliography with indexes, supplement 146, March 1982

This bibliography lists 442 reports, articles, and other documents introduced into the NASA scientific and technical system in February 1982

A preconditioned Krylov subspace approach to a tightly coupled aeromechanical system

A tightly coupled approach is attempted to compute a modest fluid-structure interaction for high subsonic flow through a converging nozzle with deformable walls. A globally convergent Newton statement and a matrix-free GMRES linear equation solver are used to linearize and solve the coupled system of equations without explicitly forming the left hand side jacobian matrix associated with the Newton method. A variable forcing function term is successfully incorporated into the Newton statement to balance inner (linear) and outer (nonlinear) iterations. The fluid-structure system is solved for comparison purposes using a loosely coupled approach. Residual convergence stagnated in the tightly coupled system approach but converged successfully in the loosely coupled approach using the same coding for domain calculations. A novel approach using time derivative preconditioning is incorporated to speed convergence of the GMRES linear equation solver. No algebraic preconditioning is used. The fluid flow equations showed significant improvements using the time derivative preconditioning method but the error term generated in the structural equations overwhelmed the physical solution increment. The Taylor Weak Statement derivation of the finite element form of the fluid flow equations with time derivative preconditioning shows a strong connection to the Streamwise Upwind Petrov Galerkin (SUPG) method. This connection is exploited to develop a theoretical basis for the damping term and the time scale parameter common to the SUPG method

ECOS 2012

The 8-volume set contains the Proceedings of the 25th ECOS 2012 International Conference, Perugia, Italy, June 26th to June 29th, 2012. ECOS is an acronym for Efficiency, Cost, Optimization and Simulation (of energy conversion systems and processes), summarizing the topics covered in ECOS: Thermodynamics, Heat and Mass Transfer, Exergy and Second Law Analysis, Process Integration and Heat Exchanger Networks, Fluid Dynamics and Power Plant Components, Fuel Cells, Simulation of Energy Conversion Systems, Renewable Energies, Thermo-Economic Analysis and Optimisation, Combustion, Chemical Reactors, Carbon Capture and Sequestration, Building/Urban/Complex Energy Systems, Water Desalination and Use of Water Resources, Energy Systems- Environmental and Sustainability Issues, System Operation/ Control/Diagnosis and Prognosis, Industrial Ecology

Abstracts on Radio Direction Finding (1899 - 1995)

The files on this record represent the various databases that originally composed the CD-ROM issue of "Abstracts on Radio Direction Finding" database, which is now part of the Dudley Knox Library's Abstracts and Selected Full Text Documents on Radio Direction Finding (1899 - 1995) Collection. (See Calhoun record https://calhoun.nps.edu/handle/10945/57364 for further information on this collection and the bibliography). Due to issues of technological obsolescence preventing current and future audiences from accessing the bibliography, DKL exported and converted into the three files on this record the various databases contained in the CD-ROM. The contents of these files are: 1) RDFA_CompleteBibliography_xls.zip [RDFA_CompleteBibliography.xls: Metadata for the complete bibliography, in Excel 97-2003 Workbook format; RDFA_Glossary.xls: Glossary of terms, in Excel 97-2003 Workbookformat; RDFA_Biographies.xls: Biographies of leading figures, in Excel 97-2003 Workbook format]; 2) RDFA_CompleteBibliography_csv.zip [RDFA_CompleteBibliography.TXT: Metadata for the complete bibliography, in CSV format; RDFA_Glossary.TXT: Glossary of terms, in CSV format; RDFA_Biographies.TXT: Biographies of leading figures, in CSV format]; 3) RDFA_CompleteBibliography.pdf: A human readable display of the bibliographic data, as a means of double-checking any possible deviations due to conversion

Space programs summary no. 37-54, volume 3 for the period 1 October to 30 November 1968. Supporting research and advanced development

Spacecraft propulsion, biological environment, guidance and control, electronic components, power supplies, propellants, instrumentation, telecommunication, and mission plannin

Six Decades of Flight Research: An Annotated Bibliography of Technical Publications of NASA Dryden Flight Research Center, 1946-2006

Titles, authors, report numbers, and abstracts are given for nearly 2900 unclassified and unrestricted technical reports and papers published from September 1946 to December 2006 by the NASA Dryden Flight Research Center and its predecessor organizations. These technical reports and papers describe and give the results of 60 years of flight research performed by the NACA and NASA, from the X-1 and other early X-airplanes, to the X-15, Space Shuttle, X-29 Forward Swept Wing, X-31, and X-43 aircraft. Some of the other research airplanes tested were the D-558, phase 1 and 2; M-2, HL-10 and X-24 lifting bodies; Digital Fly-By-Wire and Supercritical Wing F-8; XB-70; YF-12; AFTI F-111 TACT and MAW; F-15 HiDEC; F-18 High Alpha Research Vehicle, F-18 Systems Research Aircraft and the NASA Landing Systems Research aircraft. The citations of reports and papers are listed in chronological order, with author and aircraft indices. In addition, in the appendices, citations of 270 contractor reports, more than 200 UCLA Flight System Research Center reports, nearly 200 Tech Briefs, 30 Dryden Historical Publications, and over 30 videotapes are included