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Investigation of time-lapse 4D seismic tuning and spectral responses to CO₂-EOR for enhanced characterization and monitoring of a thin carbonate reservoirKrehel, Austin January 1900 (has links)
Master of Science / Department of Geology / Abdelmoneam Raef / Advancements, applications, and success of time-lapse (4D) seismic monitoring of carbonate reservoirs is limited by these systems’ inherent heterogeneity and low compressibility relative to siliciclastic systems. To contribute to the advancement of 4D seismic monitoring in carbonates, an investigation of amplitude envelope across frequency sub-bands was conducted on a high-resolution 4D seismic data set acquired in fine temporal intervals between a baseline and eight monitor surveys to track CO₂-EOR from 2003-2005 in the Hall-Gurney Field, Kansas. The shallow (approximately 900 m) Plattsburg ‘C Zone’ target reservoir is an oomoldic limestone within the Lansing-Kansas City (LKC) supergroup – deposited as a sequence of high-frequency, stacked cyclothems. The LKC reservoir fluctuates around thin-bed thickness within the well pattern region and is susceptible to amplitude tuning effects, in which CO₂ replacement of initial reservoir fluid generates a complex tuning phenomena with reduction and brightening of amplitude at reservoir thickness above and below thin-bed thickness, respectively.
A thorough analysis of horizon snapping criteria and parameters was conducted to understand the sensitivity of these autonomous operations and produce a robust horizon tracking workflow to extend the Baseline Survey horizon data to subsequent Monitor Surveys. This 4D seismic horizon tracking workflow expedited the horizon tracking process across monitor surveys, while following a quantitative, repeatable approach in tracking the LKC and maintaining geologic integrity despite low signal-to-noise ratio (SNR) data and misties between surveys. Analysis of amplitude envelope data across frequency sub-bands (30-80 Hz) following spectral decomposition identified geometric features of multiple LKC shoal bodies at the reservoir interval. In corroboration with prior geologic interpretation, shoal boundaries, zones of overlap between stacked shoals, thickness variation, and lateral changes in lithofacies were delineated in the Baseline Survey, which enhanced detail of these features’ extent beyond capacity offered from well log data. Lineaments dominated by low-frequency anomalies within regions of adjacent shoals’ boundaries suggest thicker zones of potential shoal overlap. Analysis of frequency band-to-band analysis reveals relative thickness variation. Spectral decomposition of the amplitude envelope was analyzed between the Baseline and Monitor Surveys to identify spectral and tuning changes to monitor CO₂ migration. Ambiguity of CO₂ effects on tuning phenomena was observed in zones of known CO₂ fluid replacement. A series of lineaments highlighted by amplitude brightening from the Baseline to Monitor Surveys is observed, which compete with a more spatially extensive effect of subtle amplitude dimming. These lineaments are suggestive of features below tuning thickness, such as stratigraphic structures of shoals, fractures, and/or thin shoal edges, which are highlighted by an increased apparent thickness and onset of tuning from CO₂.
Detailed analysis of these 4D seismic data across frequency sub-bands provide enhanced interpretation of shoal geometry, position, and overlap; identification of lateral changes in lithofacies suggestive of barriers and conduits; insight into relative thickness variation; and the ability of CO₂ tuning ambiguity to highlight zones below tuning thickness and improve reservoir characterization. These results suggest improved efficiency of CO₂ -EOR reservoir surveillance in carbonates, with implications to ensure optimal field planning and flood performance for analogous targets.
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Judgment of Intonation in the Context of Three-Part Woodwind Ensemble PerformancesHenry, Robert E. 08 1900 (has links)
The purpose of the study was to determine judgments of trained musicians regarding the intonation of complex tones in the context of synthesized woodwind ensemble performances. Problems included in the study were (1) estimation of the point in pitch deviation which would result in out-of-tune judgments, (2) investigation of timbral effects on judged intonation, and (3) investigation of effects of mistuning within differential voices.
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Automated Selected of Mixed Integer Program Solver ParametersStewart, Charles 30 April 2010 (has links)
This paper presents a method that uses designed experiments and statistical models to extract information about how solver parameter settings perform for classes of mixed integer programs. The use of experimental design facilitates fitting a model that describes the response surface across all combinations of parameter settings, even those not explicitly tested, allowing identification of both desirable and poor settings. Identifying parameter settings that give the best expected performance for a specific class of instances and a specific solver can be used to more efficiently solve a large set of similar instances, or to ensure solvers are being compared at their best.
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Tuning Parameter Selection in L1 Regularized Logistic RegressionShi, Shujing 05 December 2012 (has links)
Variable selection is an important topic in regression analysis and is intended to select the best subset of predictors. Least absolute shrinkage and selection operator (Lasso) was introduced by Tibshirani in 1996. This method can serve as a tool for variable selection because it shrinks some coefficients to exact zero by a constraint on the sum of absolute values of regression coefficients. For logistic regression, Lasso modifies the traditional parameter estimation method, maximum log likelihood, by adding the L1 norm of the parameters to the negative log likelihood function, so it turns a maximization problem into a minimization one. To solve this problem, we first need to give the value for the parameter of the L1 norm, called tuning parameter. Since the tuning parameter affects the coefficients estimation and variable selection, we want to find the optimal value for the tuning parameter to get the most accurate coefficient estimation and best subset of predictors in the L1 regularized regression model. There are two popular methods to select the optimal value of the tuning parameter that results in a best subset of predictors, Bayesian information criterion (BIC) and cross validation (CV). The objective of this paper is to evaluate and compare these two methods for selecting the optimal value of tuning parameter in terms of coefficients estimation accuracy and variable selection through simulation studies.
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Phase/amplitude estimation for tuning and monitoringGyongy, Istvan January 2008 (has links)
The benefits of good loop tuning in the process industries have long been recognized. Ensuring that controllers are kept well-configured despite changes in process dynamics can bring energy and material savings, improved product quality as well as reduced downtime. A number of loop tuning packages therefore exist that can, on demand, check the state of a loop and adjust the controller as necessary. These methods generally apply some form of upset to the process to identify the current plant dynamics, against which the controller can then be evaluated. A simple approach to the automatic tuning of PI controllers injects variable frequency sinewaves into the loop under normal plant operation. The method employs a phase-locked loop-based device called a phase-frequency/estimation and uses 'design-point' rules, where the aim is for the Nyquist locus of the loop to pass through a particular point on the complex plane. A number of advantages are offered by the scheme: it can carry out both 'one shot' tuning and continuous adaptation, the latter even with the test signal set to a lower amplitude than that of noise. A published article is included here that extends the approach to PID controllers, with simulations studies and real-life test showing the method to work consistently well for a for a wide range of typical process dynamics, the closed-loop having a response that compares well with that produced by standard tuning rules. The associated signal processing tools are tested by applying them to the transmitter of a Coriolis mass-flow meter. Schemes are devised for the tracking and control of the second mode of measurementtube oscillation alongside the so-called 'driven mode', at which the tubes are usually vibrated, leading to useful information being made available for measurement correction purposes. Once a loop has been tuned, it is important to assess it periodically and to detect any performance losses resulting from events such as changes in process or disturbance dynamics and equipment malfunction such as faulty sensors and actuators. Motivated by the effective behaviour of the controller tuners, a loop monitor developed here, also using probing sinewaves coupled with 'design-point' ideas. In this application, the effect on the process must be minimal, so the device must work with lower still SNRs. Thus it is practical to use a fixed-frequency probing signal, together with a different tool set for tracking it. An extensive mathematical framework is developed describing the statistical properties of the signal parameter estimates, and those of the indices derived from these estimates indicating the state of the loop. The result is specific practical guidelines for the application of the monitor (e.g. for the choices of test signal amplitude and test duration). Loop monitoring itself has traditionally been carried out by passive methods that calculate various performance indicators from routine operating data. Playing a central role amongst these metrics is the Harris Index (HI) and its variants, which compare the output variance to a 'minimum achievable' figure. A key advantage of the active monitor proposed here is that it is able not only to detect suboptimal control but also to suggest how the controller should be adjusted. Moreover, the monitor’s index provides a strong indication of changes in damping factor. Through simple adjustments to the algorithm (by raising the amplitude of the test signal or adding high frequency dither to the control signal), the method can be applied even in the presence of actuator non-linearity, allowing it to identify the cause of performance losses. This is confirmed by real-life trials on a non-linear flow rig.
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Optimalizace založená na bezderivačních a metaheuristických metodách / Optimization using derivative-free and metaheuristic methodsMárová, Kateřina January 2016 (has links)
Evolutionary algorithms have proved to be useful for tackling many practical black-box optimization problems. In this thesis, we describe one of the most powerful evolutionary algorithms of today, CMA- ES, and apply it in novel way to solve the problem of tuning multiple coupled PID controllers in combustion engine models. Powered by TCPDF (www.tcpdf.org)
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Conception de solutions technologiques et d’outils pour le traitement d’organes par ultrasons focalisés guidés par IRMLourenco de Oliveira, Philippe 11 December 2009 (has links)
Le traitement par ultrasons focalisés (HIFU) associé au contrôle par l’Imagerie de Résonance Magnétique (IRM) est une méthode prometteuse pour les thermothérapies de type non invasive sur patient en respiration libre. Une solution technologique pour l’amélioration du transfert de puissance électrique vers le transducteur ultrason autour d’un système d’adaptation d’impédance ajustable a été réalisée. Un chapitre a été consacré à la caractérisation des transducteurs par la mesure et simulation du champ acoustique spatial. Les deux derniers chapitres, concernent le développement d’outils logiciels autour de l’IRM. Une méthode de caractérisation des paramètres thermiques des tissus chauffés, utile pour une qualité d’asservissement de température optimale, a été développée. Enfin, une étude de faisabilité a été menée sur le couplage des mesures de déplacements rapides par ultrasons avec les mesures robustes fournies par IRM, ceci pour un meilleur suivi du mouvement des organes mobiles. / Treatment with Focused Ultrasound (HIFU) combined with Magnetic Resonance Imaging (MRI) control is a promising method for xxx thermotherapy on patient free breathing. A technological solution for improving the transfer of electrical power to the ultrasonic transducer around a adjustable impedance matching system has been achieved. A chapter was devoted to the characterization of transducers acoustic field by measure and simulation. The last two chapters concern the development of software tools around the MRI. A method to determinate the thermal parameters of tissues heated, useful to compute an optimal temperature control was developed. Finally, a feasibility study has been conducted on the combination of fast ultrasound motion estimation with robust MRI motion estimation, this to improve the quality of the motion tracking.
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Discrete Parameter Estimation for Rare Events: From Binomial to Extreme Value DistributionsSchneider, Laura Fee 26 April 2019 (has links)
No description available.
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[en] FRAMEWORK TO SUPPORT DATABASE TUNING / [pt] FRAMEWORK PARA APOIAR A SINTONIA FINA DE BANCO DE DADOSANA CAROLINA BRITO DE ALMEIDA 05 August 2014 (has links)
[pt] Há uma crescente demanda por ferramentas que automatizem tarefas complexas relacionadas ao SGBD, tais como aquelas relacionadas às atividades de sintonia fina. Nestas ferramentas, existe uma falta de clareza sobre as decisões e as ações que são tomadas de forma automática. Essa tese propõe um framework para execução das heurísticas de sintonia fina para apoiar o DBA (e possivelmente outros usuários) nas escolhas envolvidas na atividade de sintonia fina. Esse trabalho de pesquisa inclui uma proposta de ontologia para a sintonia fina (automática ou não) que proporciona uma abordagem formal para decisões e inferências. A contribuição inovadora dessa abordagem é oferecer transparência e
confiabilidade acerca das alternativas disponíveis para possíveis cenários no SGBD, por meio de justificativas concretas para as decisões que foram tomadas. Além disso, através do uso de uma ontologia específica, proporcionar a geração automática de novas práticas de sintonia fina, que podem ser obtidas a partir das práticas existentes (uso de inferências) ou de novas regras e conceitos que venham a surgir no futuro. Esta abordagem permite também a realização de combinações de heurísticas de sintonia fina em alto nível. / [en] There is a strong demand for automation of Database Management Systems (DBMS) tasks, as those related to self-management and self-tuning activities. However, whenever automatic decisions are made, there is also a lack of clearness about the considered decisions and actions. This thesis proposes a framework to support the DBA (and possibly other database users) on choices concerning tuning activities. This research work includes the proposal of an ontology for (autonomous or not) database tuning that enables a formal approach for decisions and inferences. The goals are to offer transparency and confidence on the available tuning alternatives with respect to the possible DBMS scenarios through a concrete justification about the decisions that are made. Moreover, new tuning practices may be obtained automatically as soon as new rules, concepts and practices are known. Finally, our approach enables an actual combination, at a high level of abstraction, of distinct database tuning strategies.
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[en] AUTOMATIC REINDEXING IN RELATIONAL DATABASES / [pt] RECRIAÇÃO AUTOMÁTICA DE ÍNDICES EM UM SGBD RELACIONALEDUARDO MARIA TERRA MORELLI 15 February 2007 (has links)
[pt] Uma dentre as muitas tarefas desempenhadas por DBAs
consiste em tentar
garantir que os tempos de respostas dos comandos
submetidos por usuários a um
grande SGBDR não excedam valores previamente acordados.
Esta dissertação
segue uma linha de estudos denominada auto-sintonia de
índices, que preconiza a
realização de ajustes automáticos na execução de consultas
SQL, visando reduzirlhes
tempos de resposta, a partir de alterações no conjunto de
índices: criação,
eliminação e recriação. Este trabalho teve como ponto de
partida a dissertação de
Marcos Salles [32], que seguiu a mesma linha, propondo um
mecanismo
automático de criação de índices. Esta dissertação estende
[32], primeiro
submetendo sua implementação a uma carga de trabalho
alternativa e depois
realizando eliminações e reconstruções de índices
automáticas, levando em
consideração níveis de preenchimento de páginas
alternativos. Também foram
realizados testes utilizando ferramentas comerciais,
Oracle 10g e SQL Server
2005, para avaliar quão eficaz comportou-se a
implementação proposta em [32].
Vale ressaltar que os testes realizados limitaram-se à
criação de índices, já que as
ferramentas não oferecem facilidades de reconstrução
automática. Diferentemente
dos trabalhos publicados nessa linha de estudos e das
ferramentas comerciais
disponíveis, foi criado um protótipo que não se limita a
sugerir novos índices;
também são eliminados os que deixaram de ser
interessantes, porém, antes ocorre
uma avaliação para verificar se a reconstrução não seria
mais adequada. Criou-se,
inclusive, uma heurística rudimentar que avalia um índice
a ser destruído e
recomenda sua reconstrução, caso atenda a determinados
requisitos. / [en] One of the most important tasks of Database Administrators
certainly is to
guarantee optimal response times to statements submitted
by users of big
RDBMS. Our dissertation deals with Index Self-tuning,
which means creating,
dropping or recreating indexes automatically, in order to
decrease SQL queries
durations. We start from Marcos Salles´ dissertation [32],
which proposed an
automatic way of creating indexes. We extend [32] in many
ways: first using a
different workload, TPC-H like. Second, following created
indexes inspecting its
usage. Finally, we have gotten to drop and, mostly,
recreate indexes using
different fillfactor in leaf pages. Also, we have
elaborated many tests using
commercial tools, Microsoft SQL Server 2005 and Oracle 10g
in order to ratify
[32] ideas. Unfortunatelly, we could not test automatic
dropping and recreating in
these tools, as long as they do not offer this kind of
functionalities. Unlike related
work and commercial tools, we have created a code
prototype that not only
suggests new indexes creations, but also drops and
recreates indexes using an own
heuristics. To validate our ideas we have used a TPC-C
like workload, but we had
to make some changes to increase updates and force
reindexing.
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