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Covello, James Anthony. "Nonlinear Bounded-Error Target State Estimation Using Redundant States." Diss., The University of Arizona, 2006. http://hdl.handle.net/10150/195557.
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When the primary measurement sensor is passive in nature--by which we mean that it does not directly measure range or range rate--there are well-documented challenges for target state estimation. Most estimation schemes rely on variations of the Extended Kalman Filter (EKF), which, in certain situations, suffer from divergence and/or covariance collapse. For this and other reasons, we believe that the Kalman filter is fundamentally ill-suited to the problems that are inherent in target state estimation using passive sensors. As an alternative, we propose a bounded-error (or set-membership) approach to the target state estimation problem. Such estimators are nearly as old as the Kalman filter, but have enjoyed much less attention. In this study we develop a practical estimator that bounds the target states, and apply it to the two-dimensional case of a submarine tracking a surface vessel, which is commonly referred to as Target Motion Analysis (TMA). The estimator is robust in the sense that the true target state does not escape the determined bounds; and the estimator is not unduly pessimistic in the sense that the bounds are not wider than the situation dictates. The estimator is--as is the problem itself--nonlinear and geometric in nature. In part, the simplicity of the estimator is maintained by using redundant states to parameterize the target's velocity. These redundant states also simplify the incorporation of other measurements that are frequently available to the system. The estimator's performance is assessed in a series of simulations and the results are analyzed. Extensions of the algorithm are considered.
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Schwarz, Lucia. "Error Models for Quantum State and Parameter Estimation." Thesis, University of Oregon, 2014. http://hdl.handle.net/1794/18526.
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Within the field of Quantum Information Processing, we study two subjects: For quantum state tomography, one common assumption is that the experimentalist possesses a stationary source of identical states. We challenge this assumption and propose a method to detect and characterize the drift of nonstationary quantum sources. We distinguish diffusive and systematic drifts and examine how quickly one can determine that a source is drifting. Finally, we give an implementation of this proposed measurement for single photons.
For quantum computing, fault-tolerant protocols assume that errors are of certain types. But how do we detect errors of the wrong type? The problem is that for large quantum states, a full state description is impossible to analyze, and so one cannot detect all types of errors. We show through a quantum state estimation example (on up to 25 qubits) how to attack this problem using model selection. We use, in particular, the Akaike Information Criterion. Our example indicates that the number of measurements that one has to perform before noticing errors of the wrong type scales polynomially both with the number of qubits and with the error size.
This dissertation includes previously published co-authored material.
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Marka, Madhavi. "Object-based unequal error protection." Thesis, Mississippi State : Mississippi State University, 2002. http://library.msstate.edu/etd/show.asp?etd=etd-06242002-152555.
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Lawson, W. Gregory 1975. "Probabilistic state estimation in regimes of nonlinear error growth." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/30291.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2005.Includes bibliographical references (p. 273-286).
State estimation, or data assimilation as it is often called, is a key component of numerical weather prediction (NWP). Nearly all implementable methods of state estimation suitable for NWP are forced to assume that errors remain in regimes of linear error growth and retain distributions of Gaussian uncertainty, yet nonlinear systems like the atmosphere can readily allow regimes of nonlinear error growth and, in turn, produce distributions of non- Gaussian uncertainty. State-of-the-art, ensemble-based methods of state estimation suitable for NWP are examined to gauge the consequences and relevance of violating the linear error growth assumption. For quite generic sources of non-Gaussian uncertainty, the methods are observed to fail, as they must, and the obtained analyses become probabilistically unreliable before becoming inaccurate. The mispositioning of coherent features is identified as a specific, geophysically relevant source of non-Gaussian uncertainty that can easily cause the state-of-the-art methods of state estimation to fail. However, an understanding of relevant phenomenology sometimes allows these same methods to remain successful owing to an available redefinition of the involved errors. The redefinition is phrased as an alternative error model. It is recognized and exploited that non-Gaussian additive Eulerian errors can come from Gaussian Lagrangian position errors. A two-step, augmented state vector approach is developed that is suitable for use with coherent features and that relies only on implementable methods of state estimation.
(cont.) By combining the dual Eulerian and Lagrangian state information into one vector, an ensemble can approximate their covariance, thus allowing each component's uncertainty to be reduced. The first step of the two-step approach reduces the feature position errors in an effort to render the residual additive errors Gaussian, thereby allowing the second step of an implementable state estimation method to proceed successfully. Philosophically, the two-step approach uses physical knowledge of the problem (as phrased by the error model) to compensate for neglected important non-Gaussian uncertainty structure in the state estimation process. The proposed two-step approach successfully allows use of implementable methods of state estimation to obtain probabilistically reliable analyses in regimes of nonlinear error growth, something unavailable using current standards.
by W. Gregory Lawson.
Ph.D.
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Carr, James. "Error analysis of X-ray photon correlation spectroscopy measurements." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=117183.
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The use of a theory to extract parameters from experimental data requires proper understanding of the statistical variation. Furthermore, the improvement of any experimental technique requires a sound understanding of the sources of error and an accurate model of how experimental parameters effect signal strength and noise. The second order intensity-intensity correlation function is the standard measured quantity in dynamic light scattering and x-ray photon correlation spectroscopy (XPCS) experiments. In this thesis we compare the measured variances of the correlation function to a model based on the statistics of dynamic light scattering. Agreement between the dynamic light scattering model and the x-ray photon correlation spectroscopy data is shown. XPCS experiments are typically conducted with low photon flux and are used to study long time constants. To achieve sufficient statistics area detectors are used. We show that there are appreciable correlations between near neighbour pixels. These correlations reveal important features that must be included to accurately draw conclusions from XPCS experiments.L'utilisation d'une théorie pour extraire des paramètres depuis des données expérimentales nécessite une compréhension des variations statistiques. De plus, l'amélioration d'une technique expérimentale repose sur la compréhension des sources d'erreurs and d'un modèle précis de l'effet des paramètres expérimentaux sur le signal et le bruit. La fonction de corrélation intensité-intensité de deuxième ordre est une quantité de mesure standardisée pour les expériences de diffusion de lumière dynamique et de spectroscopie de corrélation de photons en rayons X (X-ray Photon Correlation Spectroscopy, XPCS). Dans cette thèse, nous comparons les variances mesurées de la fonction de corrélation à un modèle basé sur les statistiques de diffusion de lumière dynamique. Nous démontrons l'accord entre le modèle de diffusion de lumière dynamique et les données XPCS. Les expériences XPCS sont en général effectuées avec un faible flux de photons et sont utilisées pourétudier les constantes à long terme. Pour atteindre des statistiques susantes, de détecteurs à résolution spatiale sont utilisés. Nous montrons l'existence de corrélations entre pixels voisins. Ces corrélations révèlent d'importantes caractéristiques qui doivent tre inclues afin de tirer des conclusions précises des expériences XPCS.
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Ji, Wenyan. "Error analysis and system improvements in phase-stepping methods for photoelasticity." Thesis, University of Sheffield, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284401.
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Ilarraza, Arantza Díaz de, Koldo Gojenola, Maite Oronoz, Maialen Otaegi, and Iñaki Alegria. "Syntactic error detection and correction in date expressions using finite-state transducers." Universität Potsdam, 2008. http://opus.kobv.de/ubp/volltexte/2008/2718/.
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This paper presents a system for the detection and correction of syntactic errors. It combines a robust morphosyntactic analyser and two groups of finite-state transducers specified using the Xerox Finite State Tool (xfst). One of the groups is used for the description of syntactic error patterns while the second one is used for the correction of the detected errors. The system has been tested on a corpus of real texts, containing both correct and incorrect sentences, with good results.
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Walia, Gursimran Singh. "Using error modeling to improve and control software quality an empirical investigation /." Diss., Mississippi State : Mississippi State University, 2009. http://library.msstate.edu/etd/show.asp?etd=etd-04032009-070637.
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Walia, Gursimran Singh. "Empirical Validation of Requirement Error Abstraction and Classification: A Multidisciplinary Approach." MSSTATE, 2006. http://sun.library.msstate.edu/ETD-db/theses/available/etd-05152006-151903/.
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Software quality and reliability is a primary concern for successful development organizations. Over the years, researchers have focused on monitoring and controlling quality throughout the software process by helping developers to detect as many faults as possible using different fault based techniques. This thesis analyzed the software quality problem from a different perspective by taking a step back from faults to abstract the fundamental causes of faults. The first step in this direction is developing a process of abstracting errors from faults throughout the software process. I have described the error abstraction process (EAP) and used it to develop error taxonomy for the requirement stage. This thesis presents the results of a study, which uses techniques based on an error abstraction process and investigates its application to requirement documents. The initial results show promise and provide some useful insights. These results are important for our further investigation.
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Behrens, Diogo. "Error isolation in distributed systems." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-203428.
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In distributed systems, if a hardware fault corrupts the state of a process, this error might propagate as a corrupt message and contaminate other processes in the system, causing severe outages. Recently, state corruptions of this nature have been observed surprisingly often in large computer populations, e.g., in large-scale data centers. Moreover, since the resilience of processors is expected to decline in the near future, the likelihood of state corruptions will increase even further.
In this work, we argue that preventing the propagation of state corruption should be a first-class requirement for large-scale fault-tolerant distributed systems. In particular, we propose developers to target error isolation, the property in which each correct process ignores any corrupt message it receives.
Typically, a process cannot decide whether a received message is corrupt or not. Therefore, we introduce hardening as a class of principled approaches to implement error isolation in distributed systems. Hardening techniques are (semi-)automatic transformations that enforce that each process appends an evidence of good behavior in the form of error codes to all messages it sends. The techniques “virtualize” state corruptions into more benign failures such as crashes and message omissions: if a faulty process fails to detect its state corruption and abort, then hardening guarantees that any corrupt message the process sends has invalid error codes. Correct processes can then inspect received messages and drop them in case they are corrupt.
With this dissertation, we contribute theoretically and practically to the state of the art in fault-tolerant distributed systems. To show that hardening is possible, we design, formalize, and prove correct different hardening techniques that enable existing crash-tolerant designs to handle state corruption with minimal developer intervention. To show that hardening is practical, we implement and evaluate these techniques, analyzing their effect on the system performance and their ability to detect state corruptions in practice.
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Balasubramanian, Ravishankar. "Adjoint-based error estimation and grid adaptation for functional outputs from CFD simulations." Diss., Mississippi State : Mississippi State University, 2005. http://sun.library.msstate.edu/ETD-db/ETD-browse/browse.
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Diamantidis, Periklis-Konstantinos. "Attitude Navigation using a Sigma-Point Kalman Filter in an Error State Formulation." Thesis, KTH, Rymd- och plasmafysik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-214459.
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Kalman filtering is a well-established method for fusing sensor data in order to accuratelyestimate unknown variables. Recently, the unscented Kalman filter (UKF) has beenused due to its ability to propagate the first and second moments of the probability distribution of an estimated state through a non-linear transformation. The design of ageneric algorithm which implements this filter occupies the first part of this thesis. The generality and functionality of the filter were tested on a toy example and the results are within machine accuracy when compared to those of an equivalent C++ implementation.Application of this filter to the attitude navigation problem becomes non-trivial when coupled to quaternions. Challenges present include the non-commutation of rotations and the dimensionality difference between quaternions and the degrees of freedom of the motion. The second part of this thesis deals with the formulation of the UKF in the quaternion space. This was achieved by implementing an error-state formulation of the process model, bounding estimation in the infinitesimal space and thus de-coupling rotations from non-commutation and bridging the dimensionality discrepancy of quaternions and their respective covariances.The attitude navigation algorithm was then tested using an IMU and a magnetometer.Results show a bounded estimation error which settles to around 1 degree. A detailed look of the filter mechanization process was also presented showing expected behavior for estimation of the initial attitude with error tolerance of 1 mdeg. The structure and design of the proposed formulation allows for trivially incorporating other sensors inthe estimation process and more intricate modelling of the stochastic processes present,potentially leading to greater estimation accuracy.Kalman filtrering är en vältablerad metod for att sammanväga sensordata för att erhålla noggranna estimat av okända variabler. Nyligen har den typ av kalman filter som kallas unscented Kalman filter (UKF) ökat i populäritet pa grund av dess förmåga att propagera de första och andra momenten för sannolikhetsfördelningen för ett estimera tillstånd genom en ickelinjär transformation. Designen av en generisk algoritm som implementerar denna typ av filter upptar den första delen av denna avhandling. Generaliteten och funktionaliteten för detta filter testades på ett minimalt exempel och resultaten var identiska med de för en ekvivalent C++-implementation till den noggrannhet som tillåts av den nita maskinprecisionen. Användandet av detta filter för attitydnavigering blir icke-trivialt när det anvands forkvaternioner. De utmaningar som uppstar inkluderar att rotationer inte kommuterar och att de finns en skillnad i dimensionalitet mellan kvaternioner och antalet frihetsgrader i rörelsen. Den andra delen av denna avhandling behandlar formuleringen av ett UKF för ett tillstånd som inkluderar en kvaternion. Detta gjordes genom att implementera en så kallad error state-formulering av processmodellen, vilken begränsar estimeringen till ett innitesimalt tillstånd och därigenom undviker problemen med att kvaternionmultiplikation inte kommuterar och överbryggar skillnaden i dimensionalitet hos kvaternioner och deras motsvarande vinkelosäkerheter.Attitydnavigeringen testades sedan med hjälp av en IMU och en magnetometer.Resultaten visade ett begränsat estimeringsfel som ställer in sig kring 1 grad. Strukturen och designen av den föreslagna formuleringen möjliggör på ett rattframt satt tillägg av andra sensorer i estimeringsprocessen och mer detaljerad modellering av de stokastiska processerna, vilket potentiellt leder till högre estimering noggrannhet.
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Asturiol, Bofill David. "Basis set superposition error effects, excited-state potential energy surface and photodynamics of thymine." Doctoral thesis, Universitat de Girona, 2010. http://hdl.handle.net/10803/7943.
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En aquesta tesi he estudiat l'efecte de l'error de superposició de base (BSSE) en la planaritat d'algunes molècules. He observat que l'ús d'alguns mètodes de càlcul amb determinades funcions de base descriuen mínims d'energia no planars per les bases nitrogenades de l'ADN. He demostrat que aquests problemes es poden arreglar utilitzant el mètode Counterpoise per corregir el BSSE en els càlculs. En aquesta tesi també he estudiat la fotofísica de la timina i els resultats mostren que existeixen dos camins de relaxació des de l'estat excitat que permeten la regeneració de l'estructura inicial de forma ultraràpida.The effect of the basis set superposition error (BSSE) on the planarity of some molecules has been studied in this thesis. I have observed that the use of some correlated methods with certain basis sets lead to non-planar minima structures of nucleobases. I have shown that the use of the Counterpoise method fixes these pitfalls in all cases. I have also studied the photophysics of thymine in this thesis and my results show that there exist two decay paths that can regenerate the initial structure of thymine in less than tenths of picoseconds upon photon absorption.
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Zhou, Zhou. "MIMO-OFDM Symbol Detection via Echo State Networks." Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/95945.
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Echo state network (ESN) is a specific neural network structure composed of high dimensional nonlinear dynamics and learned readout weights. This thesis considers applying ESN for symbol detection in multiple-input, multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) systems. A new ESN structure, namely, windowed echo state networks (WESN) is introduced to further improve the symbol detection performance. Theoretical analysis justifies WESN has an enhanced short-term memory (STM) compared with the standard ESN such that WESN can offer better computing ability. Additionally, the bandwidth spent as the training set is the same as the demodulation reference signals defined in 3GPP LTE/LTE-Advanced systems for the ESN/WESN based symbol detection. Meanwhile, a unified training framework is developed for both comb and scattered pilot
patterns. Complexity analysis demonstrates the advantages of ESN/WESN based symbol detector compared to conventional symbol detectors such as linear minimum mean square error (LMMSE) and sphere decoder when the system is employed with a large number of OFDM sub-carriers. Numerical evaluations show that ESN/WESN has an improvement of symbol detection performance as opposed to conventional methods in both low SNR regime and power amplifier (PA) nonlinear regime. Finally, it demonstrates that WESN can generate a better symbol detection result over ESN.Artificial neural networks (ANN) are widely used in recognition tasks such as recommendation systems, robotics path planning, self-driving, video tracking, image classifications, etc. To further explore the applications of ANN, this thesis considers using a specific ANN, echo state network (ESN) for a wireless communications task: MIMO-OFDM symbol detection. Furthermore, it proposed an enhanced version of the standard ESN, namely, windowed echo state network (WESN). Theoretical analyses on the short term memory (STM) of ESN and WESN show that the later one has a longer STM. Besides, the training set size of this ESN/WESN based method is chosen the same as the pilot symbols used in conventional communications systems. The algorithm complexity analysis demonstrates the ESN/WESN based method performs with lower complexity compared with conventional methods, such as linear mean square error (LMMSE) and sphere decoding. Comprehensive simulations examine how the symbol detection performance can be improved by using ESN and its variant WESN when the transmission link is non-ideal.
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Farrell, Michael David. "Error-State Estimation and Control for a Multirotor UAV Landing on a Moving Vehicle." BYU ScholarsArchive, 2020. https://scholarsarchive.byu.edu/etd/7879.
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Though multirotor unmanned aerial vehicles (UAVs) have become widely used during the past decade, challenges in autonomy have prevented their widespread use when moving vehicles act as their base stations. Emerging use cases, including maritime surveillance, package delivery and convoy support, require UAVs to autonomously operate in this scenario. This thesis presents improved solutions to both the state estimation and control problems that must be solved to enable robust, autonomous landing of multirotor UAVs onto moving vehicles.Current state-of-the-art UAV landing systems depend on the detection of visual fiducial markers placed on the landing target vehicle. However, in challenging conditions, such as poor lighting, occlusion, or extreme motion, these fiducial markers may be undected for significant periods of time. This thesis demonstrates a state estimation algorithm that tracks and estimates the locations of unknown visual features on the target vehicle. Experimental results show that this method significantly improves the estimation of the state of the target vehicle while the fiducial marker is not detected.This thesis also describes an improved control scheme that enables a multirotor UAV to accurately track a time-dependent trajectory. Rooted in Lie theory, this controller computes the optimal control signal based on an error-state formulation of the UAV dynamics. Simulation and hardware experiments of this control scheme show its accuracy and computational efficiency, making it a viable solution for use in a robust landing system.
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Parker, William David. "Speeding Up and Quantifying Approximation Error in Continuum Quantum Monte Carlo Solid-State Calculations." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1284495775.
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Boisvert, Mario. "Minimizing state error propagation in low-bit rate speech codec for voice over IP." Thesis, University of Ottawa (Canada), 2003. http://hdl.handle.net/10393/26360.
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Today's Internet and intranets are packet-switched networks where the Internet Protocol (IP) is the most widespread of all network protocols in use. Such network protocol poses serious constraints on the real-time transmission of packets such as in the case of voice applications, namely Voice over IP (VoIP) applications. The "best effort" delivery mechanism and the lack of guarantee of Quality of Service (QoS) of packet networks are known to cause packet arrival problems that result in packet losses. Obviously, the loss of packets impairs the quality of the speech at the receiving end.
In this thesis, we focus on two main areas in the implementation of VoIP systems. Initially, we review speech compression techniques to better understand the operation and characteristics of speech codecs. This allows us to select a promising speech codec, namely, the ITU-T G.729A speech codec that will be used during our demonstrations and investigations. Secondly, we review the operation of packet-switched networks, more specifically IP networks, for the purpose of understanding the degradation effects they cause to VoIP systems. With this knowledge, we formalize a set of constraints and requirements that allows us to properly analyze the effect of packet losses over IP networks.
Finally, we propose a closed-loop over the network method to assist the codec in improving its speech quality performance in periods of packet losses. The method, named State Error Correction (SEC), is described in detail and its performance is assessed through simulations.
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Jeffrey, Dennis Bernard. "Dynamic state alteration techniques for automatically locating software errors." Diss., [Riverside, Calif.] : University of California, Riverside, 2009. http://proquest.umi.com/pqdweb?index=0&did=1899476671&SrchMode=2&sid=2&Fmt=2&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1268336630&clientId=48051.
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Thesis (Ph. D.)--University of California, Riverside, 2009.Includes abstract. Title from first page of PDF file (viewed March 11, 2010). Available via ProQuest Digital Dissertations. Includes bibliographical references (p. 223-234). Also issued in print.
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May, Nora Csanyi. "A rigorous approach to comprehensive performance analysis of state-of-the-art airborne mobile mapping systems." Columbus, Ohio : Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1199309957.
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Kieweg, Michael. "An a posteriori error analysis for distributed elliptic optimal control problems with pointwise state constraints." kostenfrei kostenfrei, 2007. http://nbn-resolving.de/urn:nbn:de:bvb:384-opus-7184.
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Rapo, Mark Andrew. "Error and uncertainty in estimates of Reynolds stress using ADCP in an energetic ocean state." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/39198.
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Includes bibliographical references (leaves 189-191).Thesis (S.M. in Oceanographic Engineering)--Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Mechanical Engineering; and the Woods Hole Oceanographic Institution), 2006.
(cont.) To that end, the space-time correlations of the error, turbulence, and wave processes are developed and then utilized to find the extent to which the environmental and internal processing parameters contribute to this error. It is found that the wave-induced velocities, even when filtered, introduce error variances which are of similar magnitude to that of the Reynolds stresses.
The challenge of estimating the Reynolds stress in an energetic ocean environment derives from the turbulence process overlapping in frequency, or in wavenumber, with the wave process. It was surmised that they would not overlap in the combined wavenumber-frequency spectrum, due to each process having a different dispersion relationship. The turbulence process is thought to obey a linear dispersion relationship, as the turbulent flow is advected with the mean current (Taylor's frozen turbulence approximation). However, the Acoustic Doppler Current Profiler (ADCP) looks at radial wavenumbers and frequencies, and finds overlap. Another approach is to exploit the physical differences of each process, namely that the wave induced velocities are correlated over much larger distances than the turbulence induced velocities. This method was explored for current meters by Shaw and Trowbridge. Upon adapting the method for the ADCP, it is found that the resulting Reynolds stress estimates are of the correct order of magnitude, but somewhat noisy. The work of this thesis is to uncover the source of that noise, and to quantify the performance limits of estimating the Reynolds Stress when using ADCP measurements that are contaminated with strong wave-induced velocities.
by Mark Rapo.
S.M.in Oceanographic Engineering
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Tidefelt, Henrik. "Applied Output Error Identification: SI Engine Under Normal Operating Conditions." Thesis, Linköping University, Department of Electrical Engineering, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-2380.
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This report presents work done in the field of output error identification, with application to spark ignition (SI) engine identification for the purpose of air to fuel ratio control. The generic parts of the project consist mainly in setting out the basis for the design of output error identification software. Efficiency issues related to linear state space models have also been explored, and although the software design is not made explicit in this report, many of the important concepts have been implemented in order to provide powerful abstractions for the application to SI engine identification.
The SI engine identification data was obtained under normal operating conditions. The goal is to re- estimate models without utilizing a virtual measurement which has been used successfully to estimate models in the past. This turns out to be a difficult problem much related to the lack of excitation in the system input, shortcomings of the fuel dynamics model and the unknown and hard to estimate exhaust sensor characteristics. Indeed, the larger of the previously estimated models are found not to be identifiable in the present situation. However, trivial restrictions of the models (not meaning restriction to trivial models) avoid that problem.
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Chen, Jiaxiong. "Power System State Estimation Using Phasor Measurement Units." UKnowledge, 2013. http://uknowledge.uky.edu/ece_etds/35.
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State estimation is widely used as a tool to evaluate the real time power system prevailing conditions. State estimation algorithms could suffer divergence under stressed system conditions. This dissertation first investigates impacts of variations of load levels and topology errors on the convergence property of the commonly used weighted least square (WLS) state estimator. The influence of topology errors on the condition number of the gain matrix in the state estimator is also analyzed. The minimum singular value of gain matrix is proposed to measure the distance between the operating point and state estimation divergence.
To study the impact of the load increment on the convergence property of WLS state estimator, two types of load increment are utilized: one is the load increment of all load buses, and the other is a single load increment. In addition, phasor measurement unit (PMU) measurements are applied in state estimation to verify if they could solve the divergence problem and improve state estimation accuracy.
The dissertation investigates the impacts of variations of line power flow increment and topology errors on convergence property of the WLS state estimator. A simple 3-bus system and the IEEE 118-bus system are used as the test cases to verify the common rule. Furthermore, the simulation results show that adding PMU measurements could generally improve the robustness of state estimation.
Two new approaches for improving the robustness of the state estimation with PMU measurements are proposed. One is the equality-constrained state estimation with PMU measurements, and the other is Hachtel's matrix state estimation with PMU measurements approach. The dissertation also proposed a new heuristic approach for optimal placement of phasor measurement units (PMUs) in power system for improving state estimation accuracy. In the problem of adding PMU measurements into the estimator, two methods are investigated. Method I is to mix PMU measurements with conventional measurements in the estimator, and method II is to add PMU measurements through a post-processing step. These two methods can achieve very similar state estimation results, but method II is a more time-efficient approach which does not modify the existing state estimation software.
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Ramesh, Chithrupa, Henrik Sandberg, and Karl Henrik Johansson. "Stability analysis of multiple state-based schedulers with CSMA." KTH, Reglerteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-111461.
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In this paper, we identify sufficient conditions for Lyapunov Mean Square Stability (LMSS) of a contention-based network of first-order systems, with state-based schedulers. The stability analysis helps us to choose policies for adapting the scheduler threshold to the delay from the network and scheduler. We show that three scheduling laws can result in LMSS: constant-probability laws and additively increasing or decreasing probability laws. Our results counter the notions that increasing probability scheduling laws alone can guarantee stability of the closed-loop system, or that decreasing probability scheduling laws are required to mitigate congestion in the network.QC 20130116
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Lindblom, Johannes. "Turbo Decoding With Early State Decisions." Thesis, Linköping University, Department of Electrical Engineering, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-11694.
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Turbo codes was first presented in 1993 by C. Berrou, A. Glavieux and P. Thitimajshima. Since then this class of error correcting codes has become one of the most popular, because of its good properties. The turbo codes are able to come very close to theoretical limit, the Shannon limit. Turbo codes are for example used in the third generation of mobile phone (3G) and in the standard IEEE 802.16 (WiMAX).
There are some drawbacks with the algorithm for decoding turbo codes. The deocoder uses a Maximum A Posteriori (MAP) algorithm, which is a complex algorith. Because of the use of many variables in the decoder the decoding circuit will consume a lot of power due to memory accesses and internal communication. One way in which this can be reduced is to make early decisions.
In this work I have focused on making early decision of the encoder states. One major part of the work was also to be sure that the expressions were written in a way that as few variables as possible are needed. A termination condition is also introduced. Simulations based on estimations of the number of memory accesses, shows that the number of memory accesses will significantly decrease.
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Steeno, Gregory Sean. "Robust and Nonparametric Methods for Topology Error Identification and Voltage Calibration in Power Systems Engineering." Diss., Virginia Tech, 1999. http://hdl.handle.net/10919/39305.
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There is a growing interest in robust and nonparametric methods with engineering applications, due to the nature of the data. Here, we study two power systems engineering applications that employ or recommend robust and nonparametric methods; topology error identification and voltage calibration.
Topology errors are a well-known, well-documented problem for utility companies. A topology error occurs when a line's status in a power network, whether active or deactive, is misclassified. This will lead to an incorrect Jacobian matrix used to estimate the unknown parameters of a network in a nonlinear regression model. We propose a solution using nonlinear regression techniques to identify the correct status of every line in the network by deriving a statistical model of the power flows and injections while employing Kirchhoff's Current Law. Simulation results on the IEEE-118 bus system showed that the methodology was able to detect where topology errors occurred as well as identify gross measurement errors.
The Friedman Two-Way Analysis of Variance by Ranks test is advocated to calibrate voltage measurements at a bus in a power network. However, it was found that the Friedman test was only slightly more robust or resistant in the presence of discordant measurements than the classical F-test. The resistance of a statistical test is defined as the fraction of bad data necessary to switch a statistical conclusion. We mathematically derive the maximum resistance to rejection and to acceptance of the Friedman test, as well as the Brown-Mood test, and show that the Brown-Mood test has a higher maximum resistance to rejection and to acceptance than the Friedman test. In addition, we simulate the expected resistance to rejection and to acceptance of both tests and show that on average the Brown-Mood test is slightly more robust to rejection while on average the Friedman test is more robust to acceptance.Ph. D.
27
Akgun, Mahir. "The Effect Of Apologetic Error Messages And Mood States On Computer Users." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/3/12608479/index.pdf.
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The main aim of this study, in which 310 university students participated, is to investigate whether or not computer interfaces offering human-like apologetic error messages influence users&rsquoself-appraisals of performances and actual performances in the computerized environment. For the study, an online instructional material which includes deliberate design problems leading to user frustration was developed. The study is comprised of three phases. In the first phase, based on the CCSARP (Cross-Cultural Study of Speech Act Realization Patterns) coding manual and the studies conducted with the framework provided by the manual, apology strategy sequences were elicited from Turkish participants. Two of these apology strategy sequences were selected for producing two apology error messages. In addition to these apology messages, one plain computer error message was also developed for experimental control. The second phase of the study was conducted to determine whether these three messages were perceived as apologies. It was found out that the two apology messages were perceived as apologies and the plain computer message was not perceived as an apology. In the third phase these three messages were used to investigate the relationship between mood, self-appraisal of performance and actual performance after the transmission of the apologetic error messages. The findings of this study show that the frequencies of apology strategies preferred in the computerized environment are similar with those utilized in the social context. Statistical analyses also reveal that the influence of apology messages on self-appraisal of performance depends on participants&rsquo
mood state and the contents of the apology messages.
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Zhong, Shan. "Measurement calibration/tuning & topology processing in power system state estimation." Texas A&M University, 2003. http://hdl.handle.net/1969.1/1595.
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State estimation plays an important role in modern power systems. The errors in the telemetered measurements and the connectivity information of the network will greatly contaminate the estimated system state. This dissertation provides solutions to suppress the influences of these errors.
A two-stage state estimation algorithm has been utilized in topology error identification in the past decade. Chapter II discusses the implementation of this algorithm. A concise substation model is defined for this purpose. A friendly user interface that incorporates the two-stage algorithm into the conventional state estimator is developed.
The performances of the two-stage state estimation algorithms rely on accurate determination of suspect substations. A comprehensive identification procedure is described in chapter III. In order to evaluate the proposed procedure, a topology error library is created. Several identification methods are comparatively tested using this library.
A remote measurement calibration method is presented in chapter IV. The un-calibrated quantities can be related to the true values by the characteristic functions. The conventional state estimation algorithm is modified to include the parameters of these functions. Hence they can be estimated along with the system state variables and used to calibrate the measurements. The measurements taken at different time instants are utilized to minimize the influence of the random errors.
A method for auto tuning of measurement weights in state estimation is described in chapter V. Two alternative ways to estimate the measurement random error variances are discussed. They are both tested on simulation data generated based on IEEE systems. Their performances are compared. A comprehensive solution, which contains an initialization process and a recursively updating process, is presented.
Chapter VI investigates the errors introduced in the positive sequence state estimation due to the usual assumptions of having fully balanced bus loads/generations and continuously transposed transmission lines. Several tests are conducted using different assumptions regarding the availability of single and multi-phase measurements. It is demonstrated that incomplete metering of three-phase system quantities may lead to significant errors in the positive sequence state estimates for certain cases. A novel sequence domain three-phase state estimation algorithm is proposed to solve this problem.
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Kumar, Rahul. "Load Balancing Parallel Explicit State Model Checking." Diss., CLICK HERE for online access, 2004. http://contentdm.lib.byu.edu/ETD/image/etd455.pdf.
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Sienknecht, Ronald Theodore Jr. "An Empirical Analysis of Rating Effectiveness for a State Quality Award." Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/34129.
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This research clarified existing inconsistencies in self-assessment literature, and added to the body of knowledge for rating effectiveness of organizational assessments by defining relationships among rating effectiveness criteria (ratee, rater, rating scale, rating process) and measures (interrater reliability, halo error, leniency and severity, range restriction) based on extensive literature review. A research framework was developed from this review, and was employed in computing rating effectiveness measures at the individual (i.e., examiner or eight rating scale dimensions) and sector (e.g., Private Manufacturing Sector, Private Service Sector, Public Local Sector, Public State & Federal Sector) levels for a State Quality Award (SQA) using data from the 1998 applications.
Interrater reliability (measured by intraclass correlations for each rating scale dimension) was low to moderate, and differed by dimension. Halo error (measured by the determinant of the dimension intercorrelation matrices for each examiner) was present for all examiners. Leniency and severity (measured by presence of statistically significant Rater main effect for each dimension) was present for 11 of 32 cases, and differed by dimension. Range restriction (measured by variance analysis for each dimension) was present for 22 of 32 cases, and differed by dimension. A post-hoc principle component analysis indicated poor internal reliability for the rating scale. To improve, the SQA should replace the existing rating scale and provide in-depth training on all elements of the rating process. The importance of the SQA using boxplots, histograms, and rating effectiveness measures to make fully informed decisions was discussed.Master of Science
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Chen, Yiqi. "Computation of Initial State for Tail-Biting Trellis." Ohio University / OhioLINK, 2005. http://www.ohiolink.edu/etd/view.cgi?ohiou1125026574.
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Pece, Carlos Alessandro Zanetti. "An engineering vector-like approach to attitude kinematics & nominal attitude state tracking control." Instituto Tecnológico de Aeronáutica, 2002. http://repositorio.utfpr.edu.br/jspui/handle/1/481.
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CAPES, Fundação Casimiro Montenegro FilhoNo tratamento do movimento rotacional tridimensional de corpos rígidos é inevitável lidar-se com o fato de que rotações não são quantidades vetoriais. Elas podem, no entanto, ser tratadas como tais quando o ângulo de rotação é (muito) pequeno. Neste contexto, ou seja, o da análise infinitesimal, as derivadas temporais das variáveis de rotação mantêm um relacionamento simples (às vezes mesmo do tipo vetorial) com os componentes do vetor velocidade angular. Convencionalmente, esta distinta característica não pode ser associada a rotações grandes, nem mesmo medianas. Nesta tese é demonstrado que a relação diferencial entre o vetor rotação e o vetor velocidade angular pode, na realidade, ser expressa em termos de uma simples derivada temporal, desde que o ângulo de rotação seja mantido numa faixa moderada. O artifício permitindo tal simplicidade na equação cinemática (cinemática linear de atitude) com um ângulo de rotação moderado é a escolha criteriosa da base a partir da qual a derivada temporal é observada. Este resultado é utilizado vantajosamente em conjunto com uma versão generalizada das equações de movimento de Euler na construção de uma lei de controle simples. Essa lei realiza, concomitantemente, o rastreamento linear nominal de atitude e o rastreamento linear nominal de velocidade angular (rastreamento linear nominal de estado rotacional), dentro de uma faixa moderada de erro de rastreamento de atitude. O trabalho analítico apresentado é único no sentido em que este combina cinemática rotacional, dinâmica rotacional e controle de forma tal que linearidade nominal entre as variáveis de erro de estado é atingida mesmo para erros moderados de rastreamento de atitude. Pela primeira vez, uma lei de controle permite explicitamente que a dinâmica de erro de estado rotacional em malha fechada seja escolhida e motivada por conceitos físicos úteis da teoria linear de controle. O texto também inclui simulações numéricas que validam e ilustram os resultados teóricos obtidos.
In dealing with rigid body three-dimensional rotational motion, one is inevitably led to face the fact that rotations are not vector quantities. They may, however, be treated as such when the angle of rotation is (very) small. In this context, i.e. the infinitesimal case analysis, the time derivatives of the rotation variables hold simple (sometimes vector-like) relationships to the components of the angular velocity vector. Conventionally, this distinctive characteristic cannot be associated with general moderate-to-large rotations. In this thesis, it is demonstrated that the kinematical differential relationship between the rotation vector and the angular velocity vector may, in fact, be expressed in terms of a mere time derivative, provided that the angle of rotation is kept within moderate bounds. The key to achieve such simplicity in the kinematical equation (linear attitude kinematics) within moderate angles of rotation is a judicious choice of the basis from which the time derivative is observed. This result is used to advantage within a generalised version of Euler’s motion equations to construct a simple control law, which nominally realises both linear attitude tracking and linear angular velocity tracking (nominal linear attitude state tracking), within moderate attitude tracking errors. The analytical work presented here is unique in the sense that it combines attitude kinematics, dynamics and control in such a way that nominal linearity between the attitude state error variables is achieved within moderate attitude tracking errors. For the first time, an attitude control law explicitly enables the nominal closed-loop attitude state error dynamics to be chosen and motivated by useful physical concepts from linear control theory. The text also includes numerical simulations that validate and illustrate the theoretically achieved results.
33
Sevim, Alaettin. "Including state excitation in the fixed-interval smoothing algorithm and implementation of the maneuver detection method using error residuals." Thesis, Monterey, California : Naval Postgraduate School, 1990. http://handle.dtic.mil/100.2/ADA246336.
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Thesis (M.S. in Engineering Science)--Naval Postgraduate School, December 1990.Thesis Advisor: Titus, Harold A. Second Reader: Burl, Jeff. "December 1990." Description based on title screen as viewed on April 2, 2010. DTIC Identifier(s): Noise processing, maneuver detection. Author(s) subject terms: Kalman filter, smoothing, noise process, maneuver detection. Includes bibliographical references (p. 98-99). Also available in print.
34
Behrens, Diogo, Marco Serafini, Sergei Arnautov, Flavio Junqueira, and Christof Fetzer. "Scalable error isolation for distributed systems: modeling, correctness proofs, and additional experiments." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-203622.
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Ding, Minhua. "Multiple-input multiple-output wireless system designs with imperfect channel knowledge." Thesis, Kingston, Ont. : [s.n.], 2008. http://hdl.handle.net/1974/1335.
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Behrens, Diogo, Marco Serafini, Sergei Arnautov, Flavio Junqueira, and Christof Fetzer. "Scalable error isolation for distributed systems: modeling, correctness proofs, and additional experiments." Technische Universität Dresden, 2015. https://tud.qucosa.de/id/qucosa%3A29539.
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Ruckstuhl, Yvonne [Verfasser], and Tijana [Akademischer Betreuer] Janjic. "Joint state and parameter estimation to address model error in convective scale numerical weather prediction systems / Yvonne Ruckstuhl ; Betreuer: Tijana Janjic." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2019. http://d-nb.info/1191691586/34.
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Nusrat, Nazia. "Development of novel electrical power distribution system state estimation and meter placement algorithms suitable for parallel processing." Thesis, Brunel University, 2015. http://bura.brunel.ac.uk/handle/2438/10902.
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The increasing penetration of distributed generation, responsive loads and emerging smart metering technologies will continue the transformation of distribution systems from passive to active network conditions. In such active networks, State Estimation (SE) tools will be essential in order to enable extensive monitoring and enhanced control technologies. In future distribution management systems, the novel electrical power distribution system SE requires development in a scalable manner in order to accommodate small to massive size networks, be operable with limited real time measurements and a restricted time frame. Furthermore, a significant phase of new sensor deployment is inevitable to enable distribution system SE, since present-day distribution networks lack the required level of measurement and instrumentation. In the above context, the research presented in this thesis investigates five SE optimization solution methods with various case studies related to expected scenarios of future distribution networks to determine their suitability. Hachtel's Augmented Matrix method is proposed and developed as potential SE optimizer for distribution systems due to its potential performance characteristics with regard to accuracy and convergence. Differential Evolution Algorithm (DEA) and Overlapping Zone Approach (OZA) are investigated to achieve scalability of SE tools; followed by which the network division based OZA is proposed and developed. An OZA requiring additional measurements is also proposed to provide a feasible solution for voltage estimation at a reduced computation cost. Realising the requirement of additional measurements deployment to enable distribution system SE, the development of a novel meter placement algorithm that provides economical and feasible solutions is demonstrated. The algorithm is strongly focused on reducing the voltage estimation errors and is capable of reducing the error below desired threshold with limited measurements. The scalable SE solution and meter placement algorithm are applied on a multi-processor system in order to examine effective reduction of computation time. Significant improvement in computation time is observed in both cases by dividing the problem into smaller segments. However, it is important to note that enhanced network division reduces computation time further at the cost of accuracy of estimation. Different networks including both idealised (16, 77, 356 and 711 node UKGDS) and real (40 and 43 node EG) distribution network data are used as appropriate to the requirement of the applications throughout this thesis.
39
Brockwell, Erik. "State and industrial actions to influence consumer behavior." Doctoral thesis, Umeå universitet, Nationalekonomi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-93334.
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This thesis consists of an introductory part and three papers. Paper [I] examines how taxes affect consumption of commodities that are detrimental to health and the environment. Specifically, this paper examines if a tax increase leads to a significantly larger change in consumption than a producer price change, which is referred to as the signaling effect from taxation. The analysis uses aggregated cross-sectional time series data and information on major legislation introductions in Sweden, Denmark and the United Kingdom from 1970 to 2009. We find the main result to be that the signaling effect is significant for “Electricity” in Sweden and Denmark and significant for “Electricity” and “Petrol” in the United Kingdom. Paper [II] examines how sin taxation changes long-term consumer behavior regarding commodities which are deemed harmful for both health and the environment. These include tobacco, alcoholic beverages, sugar and confectionary, household energy, and motor fuel. Specifically, we examine the signaling effect from taxation which is seen if a tax increase leads to a significantly larger change in consumption than a producer price change. The empirical analysis is conducted by a US panel data study, during the period 1988-2012 for the four US census regions, using the Almost Ideal Demand System (AIDS). We find the main result to be that the signaling effect from taxation is significant for tobacco as well as for electricity and motor fuel. Paper [III] examines state and industry responses on consumption of cigarettes and petroleum in the United States from 1998-2012. Upon facing consumption choices, the consumer faces two competing sets of messages, one from the government and another from the industry. The objective of the state is to steer consumption in the right direction due to the harmful effects from consumption and asymmetric information among consumers. This is done mainly via taxation and state media expenditures. The industry, on the other hand, seeks to incentivize the public to ignore or reject state research and signals as well as maximizing net economic returns. This is mainly done via industry media and lobbying expenditures. We find that the main results indicate, for cigarettes, industrial media and lobbying expenditure is statistically significant on consumption. For petroleum, we find that producer prices, state media expenditure, and industrial lobbying expenditure are statistically significant on consumption.
40
Steinig, Simeon [Verfasser], and Kunibert G. [Akademischer Betreuer] Siebert. "Adaptive finite elements for state-constrained optimal control problems - convergence analysis and a posteriori error estimation / Simeon Steinig. Betreuer: Kunibert G. Siebert." Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2014. http://d-nb.info/106430897X/34.
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Fraval, Elliot, and elliot fraval@gmail com. "Minimising the Decoherence of Rare Earth Ion Solid State Spin Qubits." The Australian National University. Research School of Physical Sciences and Engineering, 2006. http://thesis.anu.edu.au./public/adt-ANU20061010.124211.
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[Mathematical symbols can be only approximated here. For the correct
display see the Abstract in the PDF files linked below] This work has
demonstrated that hyperfine decoherence times sufficiently long for
QIP and quantum optics applications are achievable in rare earth ion
centres. Prior to this work there were several QIP proposals using
rare earth hyperfine states for long term coherent storage of optical
interactions [1, 2, 3]. The very long T_1 (~weeks [4]) observed for
rare-earth hyperfine transitions appears promising but hyperfine T_2s
were only a few ms, comparable to rare earth optical transitions and
therefore the usefulness of such proposals was doubtful.
¶
This work demonstrated an increase in hyperfine T_2 by a factor of 7 ×
10^4 compared to the previously reported hyperfine T_2 for
Pr^[3+]:Y_2SiO_5 through the application of static and dynamic
magnetic field techniques. This increase in T_2 makes previous QIP
proposals useful and provides the first solid state optically active
Lamda system with very long hyperfine T_2 for quantum optics
applications.
¶
The first technique employed the conventional wisdom of applying a
small static magnetic field to minimise the superhyperfine interaction
[5, 6, 7], as studied in chapter 4. This resulted in hyperfine
transition T_2 an order of magnitude larger than the T_2 of optical
transitions, ranging fro 5 to 10 ms. The increase in T_2 was not
sufficient and consequently other approaches were required.
¶
Development of the critical point technique during this work was
crucial to achieving further gains in T_2. The critical point
technique is the application of a static magnetic field such that the
Zeeman shift of the hyperfine transition of interest has no first
order component, thereby nulling decohering magnetic interactions to
first order. This technique also represents a global minimum for back
action of the Y spin bath due to a change in the Pr spin state,
allowing the assumption that the Pr ion is surrounded by a thermal
bath. The critical point technique resulted in a dramatic increase of
the hyperfine transition T_2 from ~10 ms to 860 ms.
¶
Satisfied that the optimal static magnetic field configuration for
increasing T_2 had been achieved, dynamic magnetic field techniques,
driving either the system of interest or spin bath were investigated.
These techniques are broadly classed as Dynamic Decoherence Control
(DDC) in the QIP community. The first DDC technique investigated was
driving the Pr ion using a CPMG or Bang Bang decoupling pulse
sequence. This significantly extended T_2 from 0.86 s to 70 s. This
decoupling strategy has been extensively discussed for correcting
phase errors in quantum computers [8, 9, 10, 11, 12, 13, 14, 15], with
this work being the first application to solid state systems.
¶
Magic Angle Line Narrowing was used to investigate driving the spin
bath to increase T_2. This experiment resulted in T_2 increasing from
0.84 s to 1.12 s. Both dynamic techniques introduce a periodic
condition on when QIP operation can be performed without the qubits
participating in the operation accumulating phase errors relative to
the qubits not involved in the operation.
¶
Without using the critical point technique Dynamic Decoherence Control
techniques such as the Bang Bang decoupling sequence and MALN are not
useful due to the sensitivity of the Pr ion to magnetic field
fluctuations. Critical point and DDC techniques are mutually
beneficial since the critical point is most effective at removing high
frequency perturbations while DDC techniques remove the low frequency
perturbations. A further benefit of using the critical point technique
is it allows changing the coupling to the spin bath without changing
the spin bath dynamics. This was useful for discerning whether the
limits are inherent to the DDC technique or are due to experimental
limitations.
¶
Solid state systems exhibiting long T_2 are typically very specialised
systems, such as 29Si dopants in an isotopically pure 28Si and
therefore spin free host lattice [16]. These systems rely on on the
purity of their environment to achieve long T_2. Despite possessing a
long T_2, the spin system remain inherently sensitive to magnetic
field fluctuations. In contrast, this work has demonstrated that
decoherence times, sufficiently long to rival any solid state system
[16], are achievable when the spin of interest is surrounded by a
concentrated spin bath. Using the critical point technique results in
a hyperfine state that is inherently insensitive to small magnetic
field perturbations and therefore more robust for QIP applications.
42
Karabatsiakis, Alexander [Verfasser]. "Accelerated immunosenescence, the glial S100B protein and error-monitoring in remitted depression: A study to identify new candidates for state markers of depression / Alexander Karabatsiakis." Hannover : Bibliothek der Tierärztlichen Hochschule Hannover, 2011. http://d-nb.info/101333440X/34.
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Cheng, Sibo. "Error covariance specification and localization in data assimilation with industrial application Background error covariance iterative updating with invariant observation measures for data assimilation A graph clustering approach to localization for adaptive covariance tuning in data assimilation based on state-observation mapping Error covariance tuning in variational data assimilation: application to an operating hydrological model." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPAST067.
Full textAbstract:
Les méthodes d’assimilation de données et plus particulièrement les méthodes variationnelles sont mises à profit dans le domaine industriel pour deux grands types d’applications que sont la reconstruction de champ physique et le recalage de paramètres. Une des difficultés de mise en œuvre des algorithmes d’assimilation est que la structure de matrices de covariance d’erreurs, surtout celle d’ébauche, n’est souvent pas ou mal connue. Dans cette thèse, on s’intéresse à la spécification et la localisation de matrices de covariance dans des systèmes multivariés et multidimensionels, et dans un cadre industriel. Dans un premier temps, on cherche à adapter/améliorer notre connaissance sur les covariances d’analyse à l’aide d’un processus itératif. Dans ce but nous avons développé deux nouvelles méthodes itératives pour la construction de matrices de covariance d’erreur d’ébauche. L’efficacité de ces méthodes est montrée numériquement en expériences jumelles avec des erreurs indépendantes ou relatives aux états vrais. On propose ensuite un nouveau concept de localisation pour le diagnostic et l’amélioration des covariances des erreurs. Au lieu de s’appuyer sur une distance spatiale, cette localisation est établie exclusivement à partir de liens entre les variables d’état et les observations. Finalement, on applique une combinaison de ces nouvelles approches et de méthodes plus classiques existantes, pour un modèle hydrologique multivarié développé à EDF. L’assimilation de données est mise en œuvre pour corriger la quantité de précipitation observée afin d’obtenir une meilleure prévision du débit d’une rivière en un point donnéData assimilation techniques are widely applied in industrial problems of field reconstruction or parameter identification. The error covariance matrices, especially the background matrix in data assimilation are often difficult to specify. In this thesis, we are interested in the specification and localization of covariance matrices in multivariate and multidimensional systems in an industrial context. We propose to improve the covariance specification by iterative processes. Hence, we developed two new iterative methods for background matrix recognition. The power of these methods is demonstrated numerically in twin experiments with independent errors or relative to true states. We then propose a new concept of localization and applied it for error covariance tuning. Instead of relying on spatial distance, this localization is established purely on links between state variables and observations. Finally, we apply these new approaches, together with other classical methods for comparison, to a multivariate hydrological model. Variational assimilation is implemented to correct the observed precipitation in order to obtain a better river flow forecast
44
Giri, Suman. "A Framework for Estimating Energy Consumed by Electric Loads Through Minimally Intrusive Approaches." Research Showcase @ CMU, 2015. http://repository.cmu.edu/dissertations/564.
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This dissertation explores the problem of energy estimation in supervised Non-Intrusive Load Monitoring (NILM). NILM refers to a set of techniques used to estimate the electricity consumed by individual loads in a building from measurements of the total electrical consumption. Most commonly, NILM works by first attributing any significant change in the total power consumption (also known as an event) to a specific load and subsequently using these attributions (i.e. the labels for the events) to estimate energy for each load. For this last step, most proposed solutions in the field impart simplifying assumptions to make the problem more tractable. This has severely limited the practicality of the proposed solutions. To address this knowledge gap, we present a framework for creating appliance models based on classification labels and aggregate power measurements that can help relax many of these assumptions. Within the framework, we model the problem of utilizing a sequence of event labels to generate energy estimates as a broader class of problems that has two major components (i) With the understanding that the labels arise from a process with distinct states and state transitions, we estimate the underlying Finite State Machine (FSM) model that most likely generated the observed sequence (ii) We allow for the observed sequence to have errors, and present an error correction algorithm to detect and correct them. We test the framework on data from 43 appliances collected from 19 houses and find that it improves errors in energy estimates when compared to the case with no correction in 19 appliances by a factor of 50, leaves 17 appliances unchanged, and negatively impacts 6 appliances by a factor of 1.4. This approach of utilizing event sequences to estimate energy has implications in virtual metering of appliances as well. In a case study, we utilize this framework in order to substitute the need of plug-level sensors with cheap and easily deployable contacless sensors, and find that on the 6 appliances virtually metered using magnetic field sensors, the inferred energy values have an average error of 10:9%.
45
Gazzoni, Wanessa Carla. "Estudo do emaranhamento quantico com base na teoria da codificação cloassica." [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/261091.
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Orientadores: Reginaldo Palazzo Junior, Carlile LavorTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
Made available in DSpace on 2018-08-11T20:14:12Z (GMT). No. of bitstreams: 1 Gazzoni_WanessaCarla_D.pdf: 915784 bytes, checksum: d9b26e53c10c74a95fabe11a016027ce (MD5) Previous issue date: 2008
Resumo: Este trabalho apresenta algumas contribuições para um melhor entendimento do emaranhamento quântico e suas aplicações. Com o propósito de obter a classificação de estados quânticos puros arbitrários em separáveis ou emaranhados, apresentamos um critério de separabilidade do qual tal classificação decorre. Este critério está baseado em uma interpretação homológicageométrica, que nos permitiu formalizar algumas conclusões acerca da quantificação do emaranhamento em estados puros arbitrários com três qubits. A partir desta interpretação, foi possível também associar a descriçãao do conteúdo dos kets de um estado puro arbitrário a conceitos de teoria da codificação clássica. Tendo como base esta associação, propomos uma forma bastante simplificada para determinar a descrição matemática de estados puros arbitrários que satisfazem o máximo emaranhamento global. De acordo com conceitos da teoria da codificação, analisamos os estados de máximo emaranhamento global com relaçãoo 'a proteção contra erros que esses estados possuem. Neste contexto, apresentamos uma nova classe de estados que ainda Não havia sido mencionada na literatura.
Abstract: In this thesis we present some contributions to a better understanding of quantum entanglement and its applications. With the purpose of obtaining a classification of the arbitrary pure quantum states as separable or entangled, a separability criterion is presented. This criterion is based on an homologic-geometric interpretation which allowed us to formalize some conclusions on the entanglement quantification of arbitrary pure states with three qubits. From this interpretation, it was possible to associate a description of the kets' content of an arbitrary pure state with the concepts of the classical coding theory. Based on this association, we propose a simplified form to determine a mathematical description of arbitrary quantum states satisfying the maximum global entanglement. From the concepts of coding theory we considered the states of maximum global entanglement with respect to its inherent error protection. In this context, we present a new class of states satisfying all the previous properties and which were not known in the open literature.
Doutorado
Telecomunicações e Telemática
Doutor em Engenharia Elétrica
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Horning, Marcus. "Feedback Control for Maximizing Combustion Efficiency of a Combustion Burner System." University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1459356183.
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Bonnoit, Thierry. "Architectures pour des circuits fiables de hautes performances." Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00838425.
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Les technologies nanométriques ont réduit la fiabilité des circuits électroniques, notamment en les rendant plus sensible aux phénomènes extérieurs. Cela peut provoquer une modification des composants de stockage, ou la perturbation de fonctions logiques. Ce problème est plus préoccupant pour les mémoires, plus sensibles aux perturbations extérieures. Les codes correcteurs d'erreurs constituent l'une des solutions les plus utilisées, mais les contraintes de fiabilité conduisent à utiliser des codes plus complexes, et qui ont une influence négative sur la bande passante du système. Nous proposons une méthode qui supprime la perte de temps due à ces codes lors de l'écriture des données en mémoire, et la limite aux seuls cas où une erreur est détectée lors de la lecture. Pour cela on procède à la décontamination du circuit après qu'une donnée erronée ait été propagée dans le circuit, ce qui nécessite de restaurer certains des états précédents de quelques composants de stockage par l'ajout de FIFO. Un algorithme identifiant leurs lieux d'implémentation a également été créé. Nous avons ensuite évalué l'impact de cette méthode dans le contexte plus large suivant : la restauration d'un état précédent de l'ensemble du circuit en vue de corriger une erreur transistoire susceptible de se produire n'importe où dans le circuit.
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Neal, David A. "Utilizing Correct Prior Probability Calculation to Improve Performance of Low-Density Parity-Check Codes in the Presence of Burst Noise." DigitalCommons@USU, 2012. https://digitalcommons.usu.edu/etd/1402.
Full textAbstract:
Low-density parity-check (LDPC) codes provide excellent error correction performance and can approach the channel capacity, but their performance degrades significantly in the presence of burst noise. Bursts of errors occur in many common channels, including the magnetic recording and the wireless communications channels. Strategies such as interleaving have been developed to help compensate for bursts errors. These techniques do not exploit the correlations that can exist between the noise variance on observations in and out of the bursts. These differences can be exploited in calculations of prior probabilities to improve accuracy of soft information that is sent to the LDPC decoder.
Effects of using different noise variances in the calculation of prior probabilities are investigated. Using the true variance of each observation improves performance. A novel burst detector utilizing the forward/backward algorithm is developed to determine the state of each observation, allowing the correct variance to be selected for each. Comparisons between this approach and existing techniques demonstrate improved performance. The approach is generalized and potential future research is discussed.
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Simón, Colomar David, John-Olof Nilsson, and Peter Händel. "Smoothing for ZUPT-aided INSs." KTH, Signalbehandling, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-107414.
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Due to the recursive and integrative nature of zero-velocity-update-aided (ZUPT-aided) inertial navigation systems (INSs), the error covariance increases throughout each ZUPT-less period followed by a drastic decrease and large state estimate corrections as soon as ZUPTs are applied. For dead-reckoning with foot-mounted inertial sensors, this gives undesirable discontinuities in the estimated trajectory at the end of each step. However, for many applications, some degree of lag can be tolerated and the information provided by the ZUPTs at the end of a step can be made available throughout the step, eliminating the discontinuities. For this purpose, we propose a smoothing algorithm for ZUPT-aided INSs. For near real-time applications, smoothing is applied to the data in a step-wise manner requiring a suggested varying-lag segmentation rule. For complete off-line processing, full data set smoothing is examined. Finally, the consequences and impact of smoothing are analyzed and quantified based on real-data.QC 20130114
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Silveira, Eduarda Martins Correa da. "Crescimento econômico e restrição externa no Brasil: uma análise a partir da hipótese de Thirlwall." Universidade do Vale do Rio dos Sinos, 2015. http://www.repositorio.jesuita.org.br/handle/UNISINOS/3882.
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O objetivo principal desta dissertação foi verificar se o balanço de pagamentos é uma limitação para o crescimento econômico brasileiro, no período que compreende os anos de 1995 até 2013, considerando o arcabouço teórico de Thirlwall (1979). Para o alcance desse objetivo, foram estimadas as funções demanda por importações e exportações através de dois modelos econométricos: vetorial de correção de erros (VAR/VEC) e modelo estrutural em formato de estado de espaço para o período 1995-2013. As funções demanda por exportações e importações também foram estimadas por meio do modelo estrutural em formato de estado de espaço para o período 2001-2013, com a intenção de verificar o impacto da elevação dos preços das commodities e o aumento na demanda por esses bens nos parâmetros calculados. Pela análise, para esse período, nota-se que o processo de commoditização da pauta de exportações brasileira aprofundou o problema da restrição externa brasileira. Na estimação da função demanda por exportações, utilizando o modelo VAR/VEC, foi incluída uma variável que representou o preço das commodities. Os resultados empíricos deste trabalho confirmam que o balanço de pagamentos é uma restrição ao crescimento econômico brasileiro, dado tanto pela razão entre as elasticidades-renda das exportações e importações, como também pela baixa sensibilidade das exportações ao câmbio real. Logo, o ajuste da balança comercial via alterações suaves da taxa de câmbio tem pouca eficácia para o caso brasileiro. Além disso, as exportações são mais sensíveis aos preços das commodities do que à taxa de câmbio real.
The main objective of the present dissertation was to verify if the balance of payments was a limitation to Brazilian economic growth, in the period of the years 1995 to 2013, considering the Thirwall's Law (1979). In order to achieve this goal, export and import demand functions were estimated by two econometric models: vector error correction (VAR/VEC) and structural state space model for the period of 1995-2013. The export and import demand functions were also estimated by the structural state space model for the period of 2001-2013, with the intention of verifying the impact of the commodities price increase and the increase in the demand for these goods in the estimated parameters. According to the analysis of this period, it has been noticed that commoditization process in the Brazilian exports agenda has increased the problem of Brazilian external constraint. In the estimation of the export demand function, using the VAR/VEC model, it was included a variable which represented commodities price. The empiric results of this paper confirm that the balance of payments is a constraint to the Brazilian economic growth, given the ratio between exports and imports income elasticities and, also, the exports low sensitivity to the real exchange. Thus, the adjustment of the balance of trade by soft alterations in the exchange rate have little efficiency for the Brazilian case. Furthermore, the exports are more sensitive to the commodities price than to the real exchange rate.