Dissertations / Theses on the topic 'Symbolic state space analysis'
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Lippolis, Domenico. "How well can one resolve the state space of a chaotic map?" Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/33841.
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All physical systems are affected by some noise that limits the resolution that can be attained in partitioning their state space. For chaotic, locally hyperbolic flows, this resolution depends on the interplay of the local stretching/contraction and the smearing due to noise. My goal is to determine the `finest attainable' partition for a given hyperbolic dynamical system and a given weak additive
white noise. That is achieved by computing the local eigenfunctions of the Fokker-Planck evolution operator in linearized neighborhoods of the periodic orbits of the corresponding deterministic system, and using overlaps of
their widths as the criterion for an optimal partition. The Fokker-Planck evolution is then represented by a finite transition graph, whose spectral determinant yields time averages of dynamical observables. The method applies in
principle to both continuous- and discrete-time dynamical systems. Numerical tests of such optimal partitions on unimodal maps support my hypothesis.
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Smario, David J. "Multicorrelation analysis and state space reconstruction /." Online version of thesis, 1994. http://hdl.handle.net/1850/11443.
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Shoubaki, Ehab. "UNIFIED LARGE AND SMALL SIGNAL STATE-SPACE BASED MODELING AND SYMBOLIC SIMULATION FOR PWM CONVERTERS." Doctoral diss., University of Central Florida, 2009. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3960.
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In this Dissertation, which concentrates on discrete modeling for control purposes of DC/DC converters and simulation through symbolic techniques. A Unified Discrete State-Space Model for power converters in CCM is presented. Two main approaches to arriving at the discrete model are used. The first approach involves an impulse function approximation of the duty cycle modulation of the converter switches, and this approach results in a small signal discrete model. The Second approach is direct and does not involve any approximation of the modulation, this approach yields both a large signal nonlinear discrete model and a linear small signal model. Harmonic analysis of the converter's states at steady-state is done for steady-state waveform acquisition, which increases the accuracy of the model especially for finding the control to inductor current frequency response. Also the harmonic Analysis technique is used to both obtain the response of the converter to a load transient and to finding the optimal duty cycle response that minimizes the disturbance. Finally the Discrete model is verified for the Half-Bridge DC/DC topology for its three main control schemes (Asymmetric, Symmetric, DCS). A GUI platform in MATLAB is presented as a wrapper that utilizes the models and analysis presented in this thesis. Symbolic simulation techniques are developed in general manner for linear piecewise circuits and then through State-Space formalism specialized for DC/DC converters. A general symbolic solver programmed in JAVA that implements said techniques is presented.Ph.D.
School of Electrical Engineering and Computer Science
Engineering and Computer Science
Electrical Engineering PhD
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Freese, John Richard. "A symbolic analysis of state educational policy and reaction in a selected state, 1915-1925." Diss., The University of Arizona, 1993. http://hdl.handle.net/10150/186216.
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The role of nonpublic schools within American society has often been debated and challenged, yet for over three hundred and fifty years such schools have existed within what is now the United States. A significant portion of these nonpublic schools have been parochial schools operated by Lutheran denominations. Lutheran parochial schools were established by most European Lutheran immigrant groups to the United States, but the majority were established by German immigrants. German Lutheran immigrants to the United States initially established and maintained parochial schools to perpetuate their language, their culture, and their doctrinal standards. During World War I, extraordinary pressures from society and from the state came to bear on German Lutheran parochial schools. This study examined the public opinions and state policies within Nebraska from 1915-1925, as applied to German Lutheran parochial schools. The symbolic approach toward organizations was the analytical frame used for this study.
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Schmidt, Karsten. "Explicit state space verification." Doctoral thesis, [S.l. : s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=967940745.
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Zhu, Kunping. "Stability analysis and stabilization of fuzzy state space models." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=980973309.
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Frühwirth-Schnatter, Sylvia. "Fully Bayesian Analysis of Switching Gaussian State Space Models." Department of Statistics and Mathematics, WU Vienna University of Economics and Business, 2000. http://epub.wu.ac.at/812/1/document.pdf.
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In the present paper we study switching state space models from a Bayesian point of view. For estimation, the model is reformulated as a hierarchical model. We discuss various MCMC methods for Bayesian estimation, among them unconstrained Gibbs sampling, constrained sampling and permutation sampling. We address in detail the problem of unidentifiability, and discuss potential information available from an unidentified model. Furthermore the paper discusses issues in model selection such as selecting the number of states or testing for the presence of Markov switching heterogeneity. The model likelihoods of all possible hypotheses are estimated by using the method of bridge sampling. We conclude the paper with applications to simulated data as well as to modelling the U.S./U.K. real exchange rate. (author's abstract)Series: Forschungsberichte / Institut für Statistik
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Agrawal, Sitij. "Linear state-space analysis and optimization of StreamIt programs." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/33099.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004.Includes bibliographical references (p. 95-97).
The following thesis entails the construction, testing, modification, and analysis of two systems that couple sample ion introduction methods with a Differential Mobility Spectrometer (DMS). The sample ionization methods used with a custom designed interface for the DMS were Electrospray Ionization (ESI) and Atmospheric Pressure Matrix Assisted Laser Desorption Ionization (AP-MALDI). In addition to system development, Fourier transform and decision tree analyses were explored as alternatives to lead-cluster mapping and genetic algorithms for analyzing and classifying data produced by the systems for large biomolecules. Findings from testing and experiments using the prototype system have led to a second generation design of the interface. Results from data analysis have also provided new insights into different methods for classifying data whose form changes drastically for different sample introduction methods.
by Sitij Agrawal.
M.Eng.
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Lampka, Kai. "A symbolic approach to the state graph based analysis of high-level Markov reward models." [S.l.] : [s.n.], 2007. http://deposit.ddb.de/cgi-bin/dokserv?idn=985513926.
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Zhu, Kunping [Verfasser]. "Stability Analysis and Stabilization of Fuzzy State Space Models / Kunping Zhu." Aachen : Shaker, 2006. http://d-nb.info/1166513394/34.
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Li, Chen. "State Space Modeling and Power Flow Analysis of Modular Multilevel Converters." Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/71811.
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For the future of sustainable energy, renewable energy will need to significantly penetrate existing utility grids. While various renewable energy sources are networked with high-voltage DC grids, integration between these high-voltage DC grids and the existing AC grids is a significant technical challenge. Among the limited choices available, the modular multi-level converter (MMC) is the most prominent interface converter used between the DC and AC grids. This subject has been widely pursued in recent years. One of the important design challenges when using an MMC is to reduce the capacitor size associated with each module. Currently, a rather large capacitor bank is required to store a certain amount of line-frequency related circulating energy. Several control strategies have been introduced to reduce the capacitor voltage ripples by injecting certain harmonic current. Most of these strategies were developed using trial and error and there is a lack of a systematic means to address this issue. Most recently, Yadong Lyu has proposed to control the modulation index in order to reduce capacitor ripples. The total elimination of the unwanted circulating power associated with both the fundamental line frequency and the second-order harmonic was demonstrated, and this resulted in a dramatic reduction in capacitor size. To gain a better understanding of the intricate operation of the MMC, this thesis proposes a state-space analysis technique in the present paper. Combining the power flow analysis with the state trajectory portrayed on a set of two-dimensional state plans, it clearly delineates the desired power transfer from the unwanted circulating energy, thus leading to an ultimate reduction in the circulation energy and therefore the required capacitor volume.Master of Science
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Pasquali, Flavia. "State space models for the analysis and forecasting of climatic time series." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/23081/.
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We analyse climatic time series with state space models in order to compute the forecast distribution. The task is challenging since the temperature series are characterised by large temporal and cross-sectional dimensions. We modify and apply the three-step method proposed in Li et al. Journal of Econometrics 2020, which exploit the cross information in order to improve prediction.
We fit the linear Gaussian state space model to different univariate time series, estimating the model parameters with the Kalman filter and computing the prediction errors. The prediction error time series are then jointly analysed by means of a dynamic factor model. The estimation procedure follows the two-step approach suggested by Doz, Giannone, and Reichlin in the context of macro-economic time series nowcasting. Finally, the simulation smoother by Durbin and Koopman allows to sample scenarios conditional on the observed time series and to reconstruct the forecast distribution.
The results we obtained are promising. They demonstrate the feasibility of the entire procedure. Our explorations involved just a climatic parameter (the maximum temperature) and a reduced sample of data (8 years on a weekly basis for twenty climatic stations) , but we preliminarily tested the whole approach on much longer time series - up to 150 years - with a richer cross-sectional structure - up to 10.000 stations - experiencing viable computational times and very promising estimation results.
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Suciu, Floarea. "Performance analysis of timed Petri nets by decomposition of the state space." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0028/MQ34234.pdf.
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Halikias, George D. "A state-space analysis for a class of H∞ optimal control problems." Thesis, Imperial College London, 1990. http://hdl.handle.net/10044/1/46325.
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Özveren, Cüneyt M. "Analysis and control of discrete event dynamic systems : a state space approach." Thesis, Massachusetts Institute of Technology, 1989. http://hdl.handle.net/1721.1/14183.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1989.GRSN 409176
Includes bibliographical references (leaves 263-267).
by Cüneyt Mehmet Özveren.
Ph.D.
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Daly, Matthew Sean. "State space partition techniques for multiterminal and multicommodity flows in stochastic networks." Diss., Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/25637.
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Al, zghool Raed Ahmad Hasan. "Estimation for state space models quasi-likelihood and asymptotic quasi-likelihood approaches /." Access electronically, 2008. http://ro.uow.edu.au/theses/91.
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Lafleur, Jarret Marshall. "A Markovian state-space framework for integrating flexibility into space system design decisions." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/43749.
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The past decades have seen the state of the art in aerospace system design progress from a scope of simple optimization to one including robustness, with the objective of permitting a single system to perform well even in off-nominal future environments. Integrating flexibility, or the capability to easily modify a system after it has been fielded in response to changing environments, into system design represents a further step forward. One challenge in accomplishing this rests in that the decision-maker must consider not only the present system design decision, but also sequential future design and operation decisions. Despite extensive interest in the topic, the state of the art in designing flexibility into aerospace systems, and particularly space systems, tends to be limited to analyses that are qualitative, deterministic, single-objective, and/or limited to consider a single future time period.
To address these gaps, this thesis develops a stochastic, multi-objective, and multi-period framework for integrating flexibility into space system design decisions. Central to the framework are five steps. First, system configuration options are identified and costs of switching from one configuration to another are compiled into a cost transition matrix. Second, probabilities that demand on the system will transition from one mission to another are compiled into a mission demand Markov chain. Third, one performance matrix for each design objective is populated to describe how well the identified system configurations perform in each of the identified mission demand environments. The fourth step employs multi-period decision analysis techniques, including Markov decision processes (MDPs) from the field of operations research, to find efficient paths and policies a decision-maker may follow. The final step examines the implications of these paths and policies for the primary goal of informing initial system selection.
Overall, this thesis unifies state-centric concepts of flexibility from economics and engineering literature with sequential decision-making techniques from operations research. The end objective of this thesis' framework and its supporting analytic and computational tools is to enable selection of the next-generation space systems today, tailored to decision-maker budget and performance preferences, that will be best able to adapt and perform in a future of changing environments and requirements. Following extensive theoretical development, the framework and its steps are applied to space system planning problems of (1) DARPA-motivated multiple- or distributed-payload satellite selection and (2) NASA human space exploration architecture selection.
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Bengtsson, Thomas. "Time series discrimination, signal comparison testing, and model selection in the state-space framework /." free to MU campus, to others for purchase, 2000. http://wwwlib.umi.com/cr/mo/fullcit?p9974611.
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Zaum, Daniel [Verfasser]. "System Level Analysis of Mixed-Signal Systems using State Space Models / Daniel Zaum." München : Verlag Dr. Hut, 2011. http://d-nb.info/1017353360/34.
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Mohamed, Jama A. "Existence and stability analysis of ferroresonance using the generalized state-space averaging technique." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/46272.
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Thesis (Sc.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2000.Includes bibliographical references (p. [195]-200).
Ferroresonance can induce an undesired over-voltage often accompanied with a phase reversal which can damage power distribution transformers and motors and cause injury to the system operators. Similarly, under some conditions, power distribution transformers can excite subharmonic frequencies which in turn can damage the transformer winding and loads connected to the grid lines. While present analysis tools are based on analytical or experimental investigations, no rigorous systematic way exists to analyze ferroresonance and subharmonic problems in power distribution transformers. The purpose of this thesis is to develop a systematic methodology to study ferroresonance and subharmonic problems in power distribution transformers, particularly, their existence, stability, and bifurcations. The methodology proposed for studying the ferroresonance problem is the generalized state-space averaging technique. Both single-phase and three-phase ferroresonance are considered. Appropriate models are developed for the single phase and three-phase power distribution transformers which are suitable for the study of the ferroresonance problem, i.e, low frequency models. The theory of the incremental-input describing function is revisited and a subtle flaw in the formulation of the theory is modified to address the stability of general systems, particularly at synchronous frequency. A generalized Nyquist criterion is presented to assess the stability of the periodic solutions. The modified incremental-input describing function theory is applied to single-phase ferroresonance systems.
by Jama A Mohamed.
Sc.D.
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Han, Chao. "3D state space analysis and free-edge effect of piezoelectric laminated thick plates." Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/3d-state-space-analysis-and-freeedge-effect-of-piezoelectric-laminated-thick-plates(13cf01e1-8c3a-419e-aaf0-31b818b9c069).html.
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The accurate evaluation of interlaminar stresses is of great significance in the analysis and design of laminated and piezoelectric laminated structures because complex behaviours of these stresses near free edges initiate edge delamination that raises concerns about the structural integrity and reliability. This thesis presented 3D hybrid analyses on the interlaminar stresses to investigate the electromechanical coupling and free edge effects of piezoelectric laminated plates with an emphasis on the realistic distributions of the 3D stress and electric fields near free edges. In this research, the state space equations for simply-supported and free-edge piezoelectric laminates under transverse loads and infinite long free-edge piezoelectric laminates under uniaxial extension were obtained in the framework of 3D piezoelasticity by considering all the independent elastic and piezoelectric constants. The equations satisfy the traction-free and open-circuit boundary conditions at free edges and the continuity conditions across all interfaces. On the basis of the transfer matrix and recursive solution approaches, 3D exact solutions were sought by a novel non-uniform layer refinement technique to evaluate the accuracy of the finite element method (FEM), and realistic gradients of interlaminar stresses and electric fields were captured. The FEM results were in good agreement with those from the present solutions except for the regions near free edges. For simply-supported and free-edge laminates, stress variations with material properties, geometries and stacking sequences were obtained. The interlaminar stress τxz was dominant at corners and τyz also tended to contribute to delamination. In the infinite long free-edge laminates, σz, τyz, Ey and Ez exhibited significant gradients near free edges. Furthermore, the considerable influence of the electromechanical coupling effect on interlaminar stresses revealed that piezoelectric laminates were more susceptible to edge delamination and the application of closed-circuited surface conditions might prevent such edge delamination. The present analytical solution demonstrated an improvement in precision over other 2D analytical and numerical solutions and could serve as a benchmark for the determination of interlaminar stresses and electric fields near the free edges of the piezoelectric laminates.
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Jacobson, Jay Alan. "State space partitioning methods for solving a class of stochastic network problems." Diss., Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/24928.
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Foley, Dawn Christine. "Applications of State space realization of nonlinear input/output difference equations." Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/16818.
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Thompson, Barrett Michael. "An analysis of the state space graph for integer permutation with application to local search." Thesis, Georgia Institute of Technology, 1988. http://hdl.handle.net/1853/25027.
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Pola, Contreras Daniel. "An improved prognosis strategy with temperature dependent state-space model for the analysis of the state-of-health and state-for-charge in lithium-ion batteries." Tesis, Universidad de Chile, 2014. http://www.repositorio.uchile.cl/handle/2250/130476.
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Magíster en Ciencias de la Ingeniería, Mención EléctricaIngeniero Civil Eléctrico
Actualmente existe una gran cantidad de equipos y dispositivos que utilizan baterías como su fuente primaria o secundaria de energía. Para estos sistemas es crítico contar con información del desempeño de sus baterías, dado que este conocimiento puede ayudar a tomar decisiones apropiadas y asegurar autonomía en el tiempo. Dos importantes variables que deben ser monitoreadas son el "Estado-de-Salud" (SOH, del inglés State-of-Health) y el "Estado-de-Carga" (SOC, del inglés State-of-Charge). Este trabajo se enfoca en generar esquemas de pronóstico para ambas variables, donde se tome en cuenta la temperatura de operación. Con este propósito, se diseñaron y realizaron un conjunto de pruebas de laboratorio con celdas de Ion-Litio donde se caracterizó el impacto de la temperatura en factores tales como la energía entregada en un ciclo, la impedancia interna, o tendencia de degradación. A partir de estos datos, y esquemas existentes en la literatura, se proponen modelos empíricos para la degradación y para la descarga de una batería mediante una representación de espacio-estados, definiendo directamente un estado como el SOH y el SOC respectivamente. Las estimaciones y predicciones a largo plazo se efectúan bajo un enfoque Bayesiano, basado en el filtro de partículas. Además, se propone la implementación de lazos de control externos para corregir condiciones iniciales erróneas de los estados, y un módulo de detección de outliers para trabajar con datos perdidos o inválidos. La validación de estos esquemas se realiza con datos generados en laboratorio, además de datos de degradación publicados por NASA Ames Prognostic Center of Excellence. El esquema propuesto para el SOH es capaz de incorporar explícitamente el efecto de la temperatura de operación (bajo el concepto de "Capacidad Usable"), y estimar y pronosticar el SOH a una temperatura de referencia. Por otro lado, el esquema para el SOC fue validado incluyendo una mejor representación de la fenomenología del proceso de descarga comparada a la existente, y se deja una propuesta de cómo incluir el efecto de la temperatura en el modelo. La implementación de estos esquemas de pronóstico permite la incorporación de la temperatura de operación, que a pesar de su gran influencia en el comportamiento de las baterías es considerada constante en muchos casos presentes en la literatura; además de incluir algunas mejoras prácticas en los algoritmos de estimación. Las propuestas de este trabajo dejan las bases para avanzar en la incorporación de otros fenómenos importantes como la profundidad de descarga, o la magnitud de la corriente de descarga.
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Melanson, Megan Fabienne. "Extending radical space? : a historical comparative analysis of sub-state violent contention in Quebec and Corsica." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/33324.
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This thesis offers a comparative historical analysis of sub-state violent contention in Quebec and Corsica. It focuses specifically on the Front de Libération du Québec (FLQ) and the Fronte di Liberazione Naziunale Corsu (FLNC), in 1963 to 1971 and 1976 to 1990, respectively. The thesis argues that the FLQ and the FLNC sought to extend radical ideological space to promote independence in order to achieve revolutionary social and economic change through campaigns of violence and kidnappings. Theoretically, the thesis draws on the contentious politics and social movements literatures, which it notably combines with Radical Flank Effect (RFE). RFEs are interactive processes that aim to map the beneficial and/or detrimental impact of radical group action on moderate groups. Whilst commonly used to understand the political outcomes of social movements, RFE is used in this thesis in conjunction with social movement literature to compare the relationship between these violent movements and their more moderate opponents. To understand the internal dynamics of these movements, I have identified four key elements of contrast: membership, ideology, network structure and strategy. I draw on, for example, McAdam, Tarrow and Tilly's (2001) mobilization method, which aids an understanding of membership and ideology by framing the interaction amongst challengers, their opponents and the media. This thesis seeks to understand FLQ and FLNC mobilization in light of the aim to shape and develop radical ideological space in the sub-states of Quebec and Corsica. It draws on an extensive study of archival data that includes police reports that have only recently been made available in Canada, transcripts of court cases, newspapers, and an interview with a former member of the FLNC, as well as secondary sources. The central orienting question is: what explains the contrasting patterns of sub-state violent contention in Quebec and Corsica? More specifically, why did the FLQ dissolve in 1971, yet the FLNC continued its violent trajectory, albeit less political and nationalist, until 2014? The FLQ and the FLNC differently subscribed to Marxism and postcolonialism. The FLQ was committed to a Marxist program of revolutionary change, and this commitment was shared by the FLNC until the collapse of communism in central and Eastern Europe in 1989. FLQ members considered themselves 'urban revolutionaries' and employed Marxism to understand the economic disparity in industrial Montreal. Early Corsican violent contention, in contrast, included Maoist influences, in particular, through their demand for agrarian reform. The two groups viewed the relationship between their sub-states (Quebec and Corsica) and central states (Canada and France) through a colonial lens, and understood their mobilization against these states and elite minorities (the Anglophone elite in Quebec and the pieds noirs in Corsica) in this light. Both violent movements targeted this colonial relationship. Both the FLQ and FLNC manifestos were economically and politically focused, land and culture were additionally highlighted by the FLNC. This thesis found that sub-state violent contention in the very different contexts of Quebec and Corsica shared an overall pattern, an arc of violent mobilization. The initial mobilization developed from a frustration with moderate political groups; radicalization grew and new tactics were embraced; until turning points that included the assassination of Pierre Laporte by the FLQ and the division of the FLNC into competitive factions, and then a decline of activity, mobilization and recruitment. Although the FLQ and the FLNC contrasted greatly in terms of membership, ideology, organization and strategy, both groups attempted to extend radical space through the use of violent contention in these two very different nations. Ultimately, however, while the FLQ and the FLNC were able to extend or maintain radical space at times, yet they failed to sustain the extension of ideological radical space on the basis on their revolutionary manifestos.
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Jo, Seung-Koo. "An analysis and schematic review of circulation and open space on central Kansas State University campus." Kansas State University, 1991. http://hdl.handle.net/2097/36102.
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Castet, Jean-François. "Reliability, multi-state failures and survivability of spacecraft and space-based networks." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/45871.
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Spacecraft fulfill a myriad of critical functions on orbit, from defense and intelligence to science, navigation, and telecommunication. Spacecraft can also cost several hundred millions of dollars to design and launch, and given that physical access for maintenance remains difficult if not impossible to date, designing high reliability and survivability into these systems is an engineering and financial imperative. While reliability is recognized as an essential attribute for spacecraft, little analysis has been done pertaining to actual field reliability of spacecraft and their subsystems. This thesis consists of two parts. The first part fills the gap in the current understanding of spacecraft failure behavior on orbit through extensive statistical analysis and modeling of anomaly and failure data of Earth-orbiting spacecraft. The second part builds on these results to develop a novel theoretical basis (interdependent multi-layer network approach) and algorithmic tools for the analysis of survivability of spacecraft and space-based networks. Space-based networks (SBNs) allow the sharing of on-orbit resources, such as data storage, processing, and downlink. Results indicate and quantify the incremental survivability improvement of the SBN over the traditional monolith architecture. A trade-space analysis is then conducted using non-descriptive networkable subsystems/technologies to explore survivability characteristics of space-based networks and help guide design choices.
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Upadhyay, Indrima. "ANALYSIS OF Q- LEARNING BASED GAME PLAYING AGENTS FOR ABSTRACT BOARD GAMES WITH INCREASING STATE-SPACE COMPLEXITY." Miami University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=miami1627681408588176.
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Tsuji, Karl Sei. "Lead-lag relationships among precious metals prices and economic determinants of capital flows: A state-space analysis." Diss., The University of Arizona, 1996. http://hdl.handle.net/10150/187508.
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Lead-lag relationships among precious-metals prices and their early-warning potential of shifts in exchange rates and inflation is debated. By examining a suite of precious-metals prices by multivariate State-Space analysis, this research goes beyond previous studies that focus upon gold, and avoids ad-hoc lag-length specification that plagues other methods. Precious-metals prices and structural economic variables are selected in accord with economic theory from a reduced-form model that recognizes both stock and flow components of precious-metals markets. Structure of the ARMA equations corresponding to the resulting State-Space models allows for testing lead-lag relationships among the variables. With monthly first-differenced real price and rate data, current prices of gold, silver, and platinum are sensitive to not only the interest-rate component of the cost of carry but also to expected future own-prices. But among these precious metals, only gold prices lead platinum prices, which suggests precious-metals are traded in more separable markets and are less substitutable as assets in a monthly time-frame than commonly perceived and that speculative activity from the gold market spills over into silver before platinum. Precious-metals prices do not lead exchange rates but exchange rates do lead platinum prices which suggests that exchange-rate disequilibria impacts gold and silver more quickly than the less-liquid platinum market. Furthermore, gold prices, with monthly first-differenced data in both nominal and real terms, do not lead interest rates, exchange rates, or inflation, and hypotheses that gold prices exhibit leading relationships to these structural economic variables are rejected. Likewise, the potential of precious-metals prices as early-warning indicators of shifts in economic determinants of capital flows is questioned.
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Hester, Michael. "America's #1 fan a rhetorical analysis of presidential sports encomia and the symbolic power of sports in the articulation of civil religion in the United States /." unrestricted, 2005. http://etd.gsu.edu/theses/available/etd-04202005-135131/.
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Thesis (Ph. D.)--Georgia State University, 2005.Mary Stuckey, committee chair; Carol Winkler, M. Lane Bruner, David Cheshier, James Darsey, Daniel Franklin, committee members. Electronic text (316 p.) : digital, PDF file. Description based on contents viewed July 16, 2007. Includes bibliographical references (p. 301-316).
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PIZZINGA, ADRIAN HERINGER. "STATE SPACE MODELS WITH RESTRICTIONS IN COMPONENTS OF INTEREST: APPLICATIONS IN DYNAMIC STYLE ANALYSIS FOR BRAZILIAN INVESTMENT FUNDS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2004. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=4745@1.
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COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOREsta Dissertação procura, sob um enfoque freqüentista, discutir tecnologias para que se imponham restrições no processo de estimação de componentes não observáveis associadas a um modelo em Espaço de Estado (EE) arbitrário. O escopo do texto abrange desde procedimentos propostos pioneiramente por Howard Doran para restrições de igualdade, lineares e/ou não lineares, invariantes ou variantes no tempo, em modelos em EE lineares, até a adoção e o ajuste de estruturas mais delicadas, como os modelos em EE não lineares. Entende-se que estes últimos se constituem em uma alternativa relevante, caso seja requerida, por exemplo, a imposição de restrições de desigualdade. Técnicas e estratégias de implementação são apresentadas, debatidas e comparadas, incluindo-se também o processo de estimação de parâmetros desconhecidos e a questão de diagnósticos. Ao final, são apresentados exercícios empíricos com base nas tecnologias discutidas. Os modelos propostos para esta ilustração visam à realização da análise dinâmica de estilo baseado no retorno para carteiras de investimento brasileiras (a versão estática desses modelos fora introduzida por William Sharpe, para carteiras norte-americanas), os quais devem, eventualmente, abranger dois tipos de restrições nas componentes de interesse, quais sejam, um de igualdade e outro de desigualdade.
This Dissertation aims, in a frequentist way, to discuss technologies for imposing restrictions in non-observable components associated with an arbitrary State Space (SS) model. The text scope ranges from procedures proposed originally by Howard Doran for equality, linear or non- linear, time invariant or time varying restrictions in a linear SS model, to adoption and estimation of more complicated structures like non-linear SS models. It is understood that these last ones are a relevant alternative, in cases of, for instance, inequality restrictions requirement. Implementation techniques and strategies are given, debated and compared, also including unknown parameters estimation and diagnostics analysis. At the end, empirical exercises are presented based on discussed methodologies. The proposed models for this illustration aim at dynamic return based style analysis for Brazilian investment portfolios (the static version of these models had been introduced by William Sharpe, for American portfolios), which shall eventually satisfy two kinds of restrictions on components of interest, namely one of equality and other of inequality.
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Allgaier, Nicholas. "Reverse Engineering the Human Brain: An Evolutionary Computation Approach to the Analysis of fMRI." ScholarWorks @ UVM, 2015. http://scholarworks.uvm.edu/graddis/383.
Full textAbstract:
The field of neuroimaging has truly become data rich, and as such, novel analytical methods capable of gleaning meaningful information from large stores of imaging data are in high demand. Those methods that might also be applicable on the level of individual subjects, and thus potentially useful clinically, are of special interest. In this dissertation we introduce just such a method, called nonlinear functional mapping (NFM), and demonstrate its application in the analysis of resting state fMRI (functional Magnetic Resonance Imaging) from a 242-subject subset of the IMAGEN project, a European study of risk-taking behavior in adolescents that includes longitudinal phenotypic, behavioral, genetic, and neuroimaging data.
Functional mapping employs a computational technique inspired by biological evolution to discover and mathematically characterize interactions among ROI (regions of interest), without making linear or univariate assumptions. Statistics of the resulting interaction relationships comport with recent independent work, constituting a preliminary cross-validation. Furthermore, nonlinear terms are ubiquitous in the models generated by NFM, suggesting that some of the interactions characterized here are not discoverable by standard linear methods of analysis. One such nonlinear interaction is discussed in the context of a direct comparison with a procedure involving pairwise correlation, designed to be an analogous linear version of functional mapping. Another such interaction suggests a novel distinction in brain function between drinking and non-drinking adolescents: a tighter coupling of ROI associated with emotion, reward, and interceptive processes such as thirst, among drinkers. Finally, we outline many improvements and extensions of the methodology to reduce computational expense, complement other analytical tools like graph-theoretic analysis, and possibly allow for voxel level functional mapping to eliminate the necessity of ROI selection.
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Banga, Mainak. "Partition based Approaches for the Isolation and Detection of Embedded Trojans in ICs." Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/34924.
Full textAbstract:
This thesis aims towards devising a non-destructive testing methodology for ICs fabricated
by a third party manufacturer to ensure the integrity of the chip. With the growing trend of
outsourcing, the sanity of the final product has emerged to be a prime concern for the end
user. This is especially so if the components are to be used in mission-critical applications
such as space-exploration, medical diagnosis and treatment, defense equipments such as
missiles etc., where a single failure can lead to a disaster. Thus, any extraneous parts
(Trojans) that might have been implanted by the third party manufacturer with a malicious
intent during the fabrication process must be diagnosed before the component is put to use.
The inherent stealthy nature of Trojans makes it difficult to detect them at normal IC outputs. More so, with the restriction that one cannot visually inspect the internals of an IC after it has been manufactured. This obviates the use of side-channel signal(s) that acts like a signature of the IC as a means to assess its internal behavior under operational conditions.
In this work, we have selected power as the side-channel signal to characterize the internal
behavior of the ICs. We have used two circuit partitioning based approaches for isolating and
enhancing the behavioral difference between parts of a genuine IC and one with a sequence
detector Trojan in it. Experimental results reveal that these approaches are effective in
exposing anomalous behavior between the targeted ICs. This is reflected as difference in
power-profiles of the genuine and maligned ICs that is magnified above the process variation
ensuring that the discrepancies are observable.
Master of Science
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Anniballi, Giulio. "Analysis of superconducting Rutherford cables through a lumped parameter circuit." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.
Find full textAbstract:
The upgrade of the LHC, High Luminosity Large Hadron Collider requires more powerful bending magnets. Four of the 1232 dipoles based on Nb-Ti technology will be replaced with magnets made of Nb3Sn in order to create space for collimators.
This technology will allow the induction magnetic field of the magnets to pass from 8 to 11 Tesla. In this way, shorter magnets are needed for the same integrated field.
Nb3Sn has never been used in magnet technology and its use represents a technological challenge. One of the main characteristic of Nb3Sn is its fragility. This feature could damage one or more of the forty strands of the Rutherford Cable during cool down and assembling phase, creating a breakage. The current flow will be interrupted in correspondence to the breakage and in order to preserve the transport current, it has to flow from the broken strand to others (current distributions).
The aim of this thesis focuses on the analysis of a Rutherford superconducting cable with a breakage through lumped parameter circuits.
In the first phase, a steady state model has been developed to allow us to calculate the values of the adjacent and crossing strands as a function of the spatial coordinate during current plateau.
In order to reduce the complexity of the problem, the developed circuit is made of only three strands. Each of these strands represent a typology in which the forty strands of the cable have been divided : broken, adjacent and crossing strands.
The model has been validated by a comparison with numerical software THEA (Thermal, Hydraulic and Electric Analysis of a generic superconducting cable).
Subsequently of the validation, some parametric studies have been carried out in order to understand which physical parameters of the cable play a key role in the current distribution.
In the second phase, the time dependence of the model has been implemented by adding dynamic components.
The circuit under exam has been solved through state space representation.
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Baldwin, Mark W. "Modal Analysis Techniques in Wide-Area Frequency Monitoring Systems." Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/26522.
Full textAbstract:
The advent of synchronized wide-area frequency measurements obtained from frequency disturbance recorders and phasor measurement units has presented the power industry with special opportunities to study power system dynamics. I propose the use of wide-area frequency measurements in identifying system disturbances based on power system post-event modal properties.
In this work, power system dynamics are examined from an internal system energy viewpoint. Since an electric power system is composed of coupled rotating machines (large generators) which have air gap magnetic fields that are essentially static, or quasi-static, the power system may be modeled as a system with energy stored in quasi-static magnetic fields. The magnetic fields in the machines do change with time but may be modeled as static as far as wave propagation is concerned. The dynamic model that I develop treats this magnetic energy specifically as potential energy. Each rotating machine also contains an inertia due to the mass and motion of its rotor train and so each machine contains a rotational kinetic energy. Thus the internal system energy for a power system dynamic model may be considered to be contained in potential (magnetic) and kinetic (rotating mass) energies. This notion of internal energy lends itself to the use of a state-space model where each system state is associated with either a kinetic energy or a potential energy. An n-machine system would have a total of 2n states and would thus be a 2n-th order system. For many power system disturbances, I postulate that a linearized version of this model may be used to examine system natural response in terms of frequency and phasor measurements. The disturbances that I will investigate include generator and line outages. For any particular outage, the power system exhibits a very specific natural response in terms of its kinetic and potential energies. Kinetic energy in the system is directly related to each specific machine's rotational speed. I propose that the kinetic energy corresponds directly with bus frequencies through a linear transformation. Likewise magnetic field energy in each machine corresponds directly with a torque angle. The potential energy in the system thus corresponds directly with bus angles through a linear transformation.
The primary focus of this work is on frequency deviation modal characteristics – specifically damped oscillation frequencies, mode shapes, and damping ratios. This work presents how specific disturbances on a power system will lead to specific oscillation frequencies in the deviation quantities and that these oscillation frequencies may be used to identify the disturbance. The idea of disturbance identification stems out of previous work done in locating disturbances by using a distributed parameter (DP) model of an electric power system. This DP model, which assumes a wave-like motion of frequency and phase quantities, was used to locate disturbances via a triangulation method. This present work, instead of using a DP model of the power system, assumes lumped parameters and focuses on disturbance identification strictly via modal characteristics – particularly oscillation frequency in the frequency deviations. This model is not concerned with geographic location but focuses on system topology, loading, and machine mass as lumped parameters. Advantages of disturbance identification include mainly reliability enhancements but can also be used in marketing applications.
The state-space model used to realize this theory is verified via simulation using small, "academic" systems which should prove useful in classroom settings. Additionally the model is verified on a larger test system in order prove its validity and potential usefulness on large power systems.Ph. D.
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Kashefi, Kaviani Ali. "Dynamic Modeling and Analysis of Single-Stage Boost Inverters under Normal and Abnormal Conditions." FIU Digital Commons, 2012. http://digitalcommons.fiu.edu/etd/655.
Full textAbstract:
Inverters play key roles in connecting sustainable energy (SE) sources to the local loads and the ac grid. Although there has been a rapid expansion in the use of renewable sources in recent years, fundamental research, on the design of inverters that are specialized for use in these systems, is still needed. Recent advances in power electronics have led to proposing new topologies and switching patterns for single-stage power conversion, which are appropriate for SE sources and energy storage devices. The current source inverter (CSI) topology, along with a newly proposed switching pattern, is capable of converting the low dc voltage to the line ac in only one stage. Simple implementation and high reliability, together with the potential advantages of higher efficiency and lower cost, turns the so-called, single-stage boost inverter (SSBI), into a viable competitor to the existing SE-based power conversion technologies.
The dynamic model is one of the most essential requirements for performance analysis and control design of any engineering system. Thus, in order to have satisfactory operation, it is necessary to derive a dynamic model for the SSBI system. However, because of the switching behavior and nonlinear elements involved, analysis of the SSBI is a complicated task.
This research applies the state-space averaging technique to the SSBI to develop the state-space-averaged model of the SSBI under stand-alone and grid-connected modes of operation. Then, a small-signal model is derived by means of the perturbation and linearization method. An experimental hardware set-up, including a laboratory-scaled prototype SSBI, is built and the validity of the obtained models is verified through simulation and experiments. Finally, an eigenvalue sensitivity analysis is performed to investigate the stability and dynamic behavior of the SSBI system over a typical range of operation.
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Shoubaki, Ehab Hamed. "UNIFIED LARGE AND SMALL SIGNAL DISCRETE-SPACE MODELING FOR PWM CONVERTERS IN CCM." Master's thesis, University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3961.
Full textAbstract:
In this Thesis a Unified Discrete State-Space Model for power converters in CCM is presented. Two main approaches to arriving at the discrete model are used. The first approach involves an impulse function approximation of the duty cycle modulations of the converter switches , and this approach results in a small signal discrete model. The Second approach is direct and does not involve any approximation of the modulations , this approach yields both a large signal nonlinear discrete model and a linear small signal model. Harmonic analysis of the converter states at steady-state is done for steady-state waveform acquisition , which increases the accuracy of the model especially for finding the control to inductor current frequency response. Finally the Discrete model is verified for the Half-Bridge DC/DC topology for its three main control schemes (Asymmetric , Symmetric , DCS). A GUI platform in MATLAB is presented as a wrapper that utilizes the models and analysis presented in this thesis.M.S.E.E.
Department of Electrical and Computer Engineering
Engineering and Computer Science
Electrical Engineering
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Hu, Nan. "A unified discrepancy-based approach for balancing efficiency and robustness in state-space modeling estimation, selection, and diagnosis." Diss., University of Iowa, 2016. https://ir.uiowa.edu/etd/2224.
Full textAbstract:
Due to its generality and flexibility, the state-space model has become one of the most popular models in modern time domain analysis for the description and prediction of time series data. The model is often used to characterize processes that can be conceptualized as "signal plus noise," where the realized series is viewed as the manifestation of a latent signal that has been corrupted by observation noise.
In the state-space framework, parameter estimation is generally accomplished by maximizing the innovations Gaussian log-likelihood. The maximum likelihood estimator (MLE) is efficient when the normality assumption is satisfied. However, in the presence of contamination, the MLE suffers from a lack of robustness. Basu, Harris, Hjort, and Jones (1998) introduced a discrepancy measure (BHHJ) with a non-negative tuning parameter that regulates the trade-off between robustness and efficiency. In this manuscript, we propose a new parameter estimation procedure based on the BHHJ discrepancy for fitting state-space models. As the tuning parameter is increased, the estimation procedure becomes more robust but less efficient. We investigate the performance of the procedure in an illustrative simulation study. In addition, we propose a numerical method to approximate the asymptotic variance of the estimator, and we provide an approach for choosing an appropriate tuning parameter in practice. We justify these procedures theoretically and investigate their efficacy in simulation studies.
Based on the proposed parameter estimation procedure, we then develop a new model selection criterion in the state-space framework. The traditional Akaike information criterion (AIC), where the goodness-of-fit is assessed by the empirical log-likelihood, is not robust to outliers. Our new criterion is comprised of a goodness-of-fit term based on the empirical BHHJ discrepancy, and a penalty term based on both the tuning parameter and the dimension of the candidate model. We present a comprehensive simulation study to investigate the performance of the new criterion. In instances where the time series data is contaminated, our proposed model selection criterion is shown to perform favorably relative to AIC.
Lastly, using the BHHJ discrepancy based on the chosen tuning parameter, we propose two versions of an influence diagnostic in the state-space framework. Specifically, our diagnostics help to identify cases that influence the recovery of the latent signal, thereby providing initial guidance and insight for further exploration. We illustrate the behavior of these measures in a simulation study.
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Nassef, M. A. "Computer-aided analysis and design of non-linear and time variant multiport microwave networks using state space techniques with practical applications." Thesis, University of Kent, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375056.
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COSTA, LEANDRO SANTOS DA. "CONDITIONAL CAPM IN SPACE-STATE FORM WITH CONDITIONAL HETEROCEDASTIC DISTURBANCE: AN APPLICATION TO THE PERFORMANCE ANALYSIS OF THE BRAZILIAN EQUITY FUNDS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2016. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=27685@1.
Full textAbstract:
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
Os resultados empíricos apresentados na literatura sobre o CAPM em geral refletem as falhas teóricas do modelo em sua forma incondicional. Deste modo, duas linhas de pesquisas principais surgiram na tentativa de relaxar alguns dos pressupostos do modelo, dando origem aos chamados modelos de multifatores e modelos condicionais. Em síntese, os modelos condicionais são aqueles nos quais o valor esperado do retorno de um ativo é explicitado de forma condicional a um conjunto de informação disponível no período anterior, e a sensibilidade ao fator de risco, beta, bem como o intercepto da equação de regressão, alfa, são considerados parâmetros variantes no tempo. Este trabalho tem dois objetivos principais: (i) avaliar de forma comparativa o tratamento dos modelos CAPM condicionais na forma em espaço de estados estimados a partir do filtro de Kalman com os erros da equação de observação nas formas homocedástica e heterocedástica, com base no trabalho de Ortas, Salvador e Moneva (2014); (ii) avaliar como o uso de medidas condicionais obtidas a partir do modelo CAPM condicional sob a abordagem aqui descrita pode melhorar a prática atual de avaliação de performance dos fundos de investimentos a partir de uma amostra do mercado brasileiro. Os resultados obtidos indicam que a modelagem heterocedástica, do ponto de vista da qualidade de ajuste aos dados da amostra, é capaz de melhorar os resultados em relação ao modelo homocedástico e aos modelos incondicionais correspondentes, proporcionando, portanto, melhores práticas de avaliação de desempenho dos fundos.
The empirical results presented in the literature on the CAPM generally reflect the theoretical flaws of the model in their unconditional form. Thus, two main lines of research have emerged in an attempt to relax some of the model assumptions in its original form, giving rise to so-called multi-factor models and conditional models. In summary, the conditional models are those in which the expected value of the return of an asset is explained conditionally to a set of information available in the previous period, and the sensitivity to the risk factor, beta, as well as the intercept of the equation regression, alpha, are assumed to be time varying parameter. This work has two main objectives: (i) assess comparatively the treatment of conditional CAPM models in state-space form and estimates from the Kalman filter with the residuals of the observation equation in homocedastic and heteroskedastic forms, based on the work of Ortas, Salvador and Moneva (2014); (ii) evaluate how the use of conditional measurements obtained from the conditional CAPM under the approach previously described can improve the current practice of performance evaluation of investment funds from a sample of the Brazilian market. The results obtained indicate that heteroskedastic modeling, from the point of view of the quality of fit for the sample data, is able to provide better results in relation to homocedastic model and corresponding unconditional models, providing better practices for performance evaluation of funds.
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Ribeiro, FabrÃcio AmÃrico. "Geoeducacional strategy in south-south cooperation: an analysis of projects of integration international universities - UNILA and UNILAB." Universidade Federal do CearÃ, 2016. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=17104.
Full textAbstract:
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgicoThis research seeks to portray and analyze the process of internationalization and the international cooperation of higher education in Brazil, since 2010 mainly, when it is inaugurated the Federal University of Latin American Integration (UNILA) in the city Foz do IguaÃu-PR, with regional integration proposal, through the teaching of Latin American countries and the Caribbean, and also that year it was founded the University of International Integration of African Brazilian Lusophone (UNILAB) having an integrative proposal between the nations that make up the Community of Portuguese Language Countries (CPLC), comprising Angola, Cape Verde, Guinea Bissau, Mozambique, Portugal, Sao Tome and Principe, East Timor, Equatorial Guinea and Brazil in the city of RedenÃÃo-CE. With these universities Brazil presents to the world, an internationalization project by higher education, through a cooperation project called South, with a promise to ensure the humanistic, scientific and technological knowledge and the partnership in South Atlantic area, which appears as an area of political interest to Brazil for some time. The main aim of this research is to understand the strategies for internationalization of higher education in a globalized world, and to know how Brazil has been acting in this process. In this study we used as methodological basis, a descriptive exploratory survey on the perception of internationalization of higher education, from international universities in Brazil, and geopolitical and economic interests in Latin America and Africa. We interviewed teachers, administrative staff, students and people from the society, to get a sense of social actors involved and we based on literary scholars authors on the subject. We seek to understand in this study, how educational policies may interfere with power relations and local arrangements, allowing greater regional role in a globalized world. We obtained as results that the challenges are many, internally and externally, in the institution and in the municipalities involved, but it is geographically feasible and relevant for educational policies in the South Atlantic zone.
Essa pesquisa procura apresentar e analisar o processo de internacionalizaÃÃo e a cooperaÃÃo internacional do ensino superior no Brasil a partir principalmente do ano de 2010, quando à inaugurada a Universidade Federal da IntegraÃÃo Latino Americana (UNILA) na cidade de Foz do IguaÃu-PR, com a proposta de integraÃÃo regional, atravÃs do ensino dos paÃses da AmÃrica Latina e Caribe e tambÃm nesse ano foi fundada a Universidade da IntegraÃÃo Internacional da Lusofonia Afro-Brasileira (UNILAB) possuindo uma proposta integradora, entre as naÃÃes que compÃem a Comunidade dos PaÃses de LÃngua Portuguesa (CPLP), formada por: Angola, Cabo Verde, GuinÃ-Bissau, MoÃambique, Portugal, SÃo Tomà e PrÃncipe, Timor-Leste, Guinà Equatorial e Brasil na cidade de RedenÃÃo-CE. Com essas universidades o Brasil apresenta ao mundo um projeto de internacionalizaÃÃo, por meio do ensino superior, atravÃs de uma proposta de cooperaÃÃo denominada Sul-Sul, com a promessa de garantir o conhecimento humanÃstico, cientÃfico, tecnolÃgico e a cooperaÃÃo solidÃria na zona do AtlÃntico Sul, que se apresenta como Ãrea de interesse polÃtico para o Brasil hà algum tempo. O principal objetivo dessa pesquisa à compreender as estratÃgias para a internacionalizaÃÃo do ensino superior em um mundo globalizado, e como o Brasil vem agindo nesse processo. Nesse estudo utilizamos como embasamento metodolÃgico um levantamento descritivo e exploratÃrio sobre a percepÃÃo da internacionalizaÃÃo do ensino superior, a partir das universidades de integraÃÃo internacional no Brasil, e os interesses geopolÃticos e econÃmicos na AmÃrica Latina e na Ãfrica. Entrevistamos professores, tÃcnicos administrativos, alunos e pessoas da prÃpria sociedade, para obter uma visÃo dos atores sociais envolvidos e nos embasamos na literatura de autores estudiosos no assunto. Procuramos entender nesse estudo, como polÃticas educacionais podem interferir nas relaÃÃes de poder e nos arranjos locais, possibilitando uma maior atuaÃÃo regional em um mundo globalizado. Obtivemos como resultados que os desafios sÃo muitos, a nÃvel interno e externo, na prÃpria instituiÃÃo e nos municÃpios envolvidos, porÃm à geograficamente viÃvel e de relevÃncia para as polÃticas educacionais na zona do AtlÃntico Sul.
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Arana, Andrew Jex. "Power Systems Analysis in the Power-Angle Domain." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/30001.
Full textAbstract:
The idea of performing power systems dynamic analysis in the power-angle domain has been hinted at by previous researchers, but this may be the first published document to develop detailed techniques by which entire power systems can be represented and solved in the power-angle domain. With the widespread deployment of phasor measurement units and frequency data recorders the industry is looking for more real-time analytical tools to turn real-time wide-area measurements into useful information. Applications based on power-angle domain analysis are simple enough that they may be used online.
Power-angle domain analysis is similar to DC load-flow techniques in that a flat voltage profile is used and it is assumed that real power and voltage angle are completely decoupled from reactive power and voltage magnitude. The linearized equations for the dynamics of generators and loads are included in the model, which allows the electromechanical response to be solved using conventional circuit analysis techniques. The effect of generation trips, load switching, and line switching can be quickly approximated with nodal analysis or mesh analysis in the power-angle domain.
The analysis techniques developed here are not intended to be as accurate as time-domain simulation, but they are simpler and fast enough to be put online, and they also provide a better analytical insight into the system. Power-angle domain analysis enables applications that are not readily available with conventional techniques, such as the estimation of electromechanical propagation delays based on system parameters, the formulation of electromechanical equivalents, modal analysis, stability analysis, and event location and identification based on a small number of angle or frequency measurements. Fault studies and contingency analysis are typically performed with detailed time-domain simulations, where the electromechanical
response of the system is a function of every machine in the interconnection and the lines connecting them. All of this information is rarely known for the entire system for each operating condition; as a result, for many applications it may be more suitable to compute an approximation of the system response based on the current operating state of only the major lines and generators. Power-angle domain analysis is adept at performing such approximations.Ph. D.
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Ceccon, Stefano. "Extending Bayesian network models for mining and classification of glaucoma." Thesis, Brunel University, 2013. http://bura.brunel.ac.uk/handle/2438/8051.
Full textAbstract:
Glaucoma is a degenerative disease that damages the nerve fiber layer in the retina of the eye. Its mechanisms are not fully known and there is no fully-effective strategy to prevent visual impairment and blindness. However, if treatment is carried out at an early stage, it is possible to slow glaucomatous progression and improve the quality of life of sufferers. Despite the great amount of heterogeneous data that has become available for monitoring glaucoma, the performance of tests for early diagnosis are still insufficient, due to the complexity of disease progression and the diffculties in obtaining sufficient measurements. This research aims to assess and extend Bayesian Network (BN) models to investigate the nature of the disease and its progression, as well as improve early diagnosis performance. The exibility of BNs and their ability to integrate with clinician expertise make them a suitable tool to effectively exploit the available data. After presenting the problem, a series of BN models for cross-sectional data classification and integration are assessed; novel techniques are then proposed for classification and modelling of glaucoma progression. The results are validated against literature, direct expert knowledge and other Artificial Intelligence techniques, indicating that BNs and their proposed extensions improve glaucoma diagnosis performance and enable new insights into the disease process.
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Guo, Linyi. "Constructing an Informative Prior Distribution of Noises in Seasonal Adjustment." Thesis, Université d'Ottawa / University of Ottawa, 2020. http://hdl.handle.net/10393/41069.
Full textAbstract:
Time series data is very common in our daily life. Since they are related to time,
most of them show a periodicity. The existence of this periodic in
uence leads
to our research problem, seasonal adjustment. Seasonal adjustment is generally
applied around us, especially in areas of economy and nance. Over the last few
decades, scholars around the world made a lot of contributions in this area, and
one of the latest methods is X-13ARIMA-SEATS, which is built on ARIMA models
and linear lters. On the other hand, state space modelling (abbreviated to SSM)
is also a popular method to solve this problem and researchers including J. Durbin,
S.J. Koopman and and A. Harvery have contributed a lot of work to it. Unlike
linear lters and ARIMA models, the study on SSM starts relatively late, thus it
has not been studied and developed widely for the seasonal adjustment problem.
And SSMs have a lot advantages over those ARIMA-based and lter-based methods
such as
exibility, the understandable structure and the potential to do partial
pooling, but in practice, its default decomposition result behaves bad in some cases,
such as excessively spiky trend series; on the contrary, X-13ARIMA-SEATS could
output good decomposition result for us to analyze, but it can't be tweaked or
combined as easily as generative models and behaves like a black-box. In this paper,
we shall use Bayesian inference to combine both methods' characteristics together.
Simultaneously, to show the advantage of using SSMs concretely, we shall give a
simple application in partial pooling and talk about how to apply the Bayesian
analysis to partial pooling.
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Mallik, Wrik. "Aeroelastic Analysis of Truss-Braced Wing Aircraft: Applications for Multidisciplinary Design Optimization." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/71650.
Full textAbstract:
This study highlights the aeroelastic behavior of very flexible truss-braced wing (TBW) aircraft designs obtained through a multidisciplinary design optimization (MDO) framework. Several improvements to previous analysis methods were developed and validated.
Firstly, a flutter constraint was developed and the effects of the constraint on the MDO of TBW transport aircraft for both medium-range and long-range missions were studied while minimizing the take-off gross weight (TOGW) and the fuel burn as the objective functions. Results show that when the flutter constraint is applied at 1.15 times the dive speed, it imposes a 1.5% penalty on the take-off weight and a 5% penalty on the fuel consumption while minimizing these two objective functions for the medium-range mission. For the long-range mission, the penalties imposed by the similar constraint on the minimum TOGW and minimum fuel burn designs are 3.5% and 7.5%, respectively. Importantly, the resulting TBW designs are still superior to equivalent cantilever designs for both of the missions as they have both lower TOGW and fuel burn. However, a relaxed flutter constraint applied at 1.05 times the dive speed can restrict the penalty on the TOGW to only 0.3% and that on the fuel burn to 2% for minimizing both the objectives, for the medium-range mission. For the long-range mission, a similar relaxed constraint can reduce the penalty on fuel burn to 2.9%. These observations suggest further investigation into active flutter suppression mechanisms for the TBW aircraft to further reduce either the TOGW or the fuel burn.
Secondly, the effects of a variable-geometry raked wingtip (VGRWT) on the maneuverability and aeroelastic behavior of passenger aircraft with very flexible truss-braced wings (TBW) were investigated. These TBW designs obtained from the MDO environment while minimizing fuel burn resemble a Boeing 777-200 Long Range (LR) aircraft both in terms of flight mission and aircraft configuration. The VGRWT can sweep forward and aft relative to the wing with the aid of a Novel Control Effector (NCE) mechanism. Results show that the VGRWT can be swept judiciously to alter the bending-torsion coupling and the movement of the center of pressure of wing. Such behavior of the VGRWT is applied to both achieve the required roll control as well as to increase flutter speed, and thus, enable the operation of TBW configurations which have up to 10% lower fuel burn than comparable optimized cantilever wing designs.
Finally, a transonic aeroelastic analysis tool was developed which can be used for conceptual design in an MDO environment. Routine transonic aeroelastic analysis require expensive CFD simulations, hence they cannot be performed in an MDO environment. The present approach utilizes the results of a companion study of CFD simulations performed offline for the steady Reynolds Averaged Navier Stokes equations for a variety of airfoil parameters. The CFD results are used to develop a response surface which can be used in the MDO environment to perform a Leishman-Beddoes (LB) indicial functions based flutter analysis. A reduced-order model (ROM) is also developed for the unsteady aerodynamic system. Validation of the strip theory based aeroelastic analysis with LB unsteady aerodynamics and the computational efficiency and accuracy of the ROM is demonstrated. Finally, transonic aeroelastic analysis of a TBW aircraft designed for the medium-range flight mission similar to a Boeing 737 next generation (NG) with a cruise Mach number of 0.8 is presented. The results show the potential of the present approach to perform a more accurate, yet inexpensive, flutter analysis for MDO studies of transonic transport aircraft which are expected to undergo flutter at transonic conditions.Ph. D.
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Mergner, Sascha. "Applications of state space models in finance an empirical analysis of the time-varying relationship between macroeconomics, fundamentals and pan-European industry portfolios." Göttingen Univ.-Verl. Göttingen, 2008. http://d-nb.info/999977679/04.
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Zugl.: Göttingen, Univ., Diss., 2008 u. d. T.: Mergner, Sascha: Applications of advanced time series models to analyze the time-varying relationship between macroeconomics, fundamentals and pan-European industry portfoliosZusätzliches Online-Angebot unter http://www.sub.uni-goettingen.de
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Vega, del Valle Iliusi Donaji [Verfasser]. "Reconstruction and analysis of the state space for the identification of dynamical states in real-world time series / Iliusi Donaji Vega del Valle." Berlin : Freie Universität Berlin, 2017. http://d-nb.info/1130148289/34.
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Kadlec, Milan. "Citlivostní analýza různých typů rekonstruktoru stavu." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2012. http://www.nusl.cz/ntk/nusl-219797.
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This master thesis is focused on the sensitivity analysis of selected kinds of state reconstructors. They are realized in a general form, via direct and parallel programing. Quantity that determines the quality of sensitivity is output signal difference of the reconstructor with the general form of the system. Testing will be based on different initial state conditions and on the parameters change of the feedback A matrix due to the rested reconstructors.