The black caiman (Melanosuchus niger) and the yacare caiman (Caiman yacare) have in the past been exposed to overexploitation due to the economic profit for their hides, and therefore suffered from great declines in population sizes, especially black caimans. Legal regulation efforts made it possible for these two species to recover and today they are widely distributed in South America. Evaluation of protection and management of populations of top predators like these caimans depend on the ability to detect the animals. The probability of detecting a crocodile, or any animal, is affected by several factors such as habitat complexity and behaviour why it is of importance to acknowledge such matter in order to obtain reliable results for further implications. This study aims to investigate the detection probability and abundances in these two species as a contribution to the monitoring efforts at a local scale. Night counts were performed in Cedral lagoon located in the Beni region in Bolivia. By using the relation between marked animals and resightings of them, as well as the abundance estimate produced by the Lincoln-Petersen estimator, estimates of detection probabilities could be accounted for the total caiman population (black plus yacare caimans) and the black caiman population. Very low sighting probabilities (p = 0.03) were obtained when based on marked animals who tend to be more wary after a capture event. Those based on the L-P output were higher (total caiman population p = 0.15, black caimans p = 0.15). Population sizes were estimated to 25 ± 8.5 black caimans and 34 ± 12 caimans in total. The population size based on marked animals was 12 ± 25.4 caimans.

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.

Doctor of Philosophy / Department of Statistics / Weixing Song / The regression model has been given a considerable amount of attention and played a significant role in data analysis. The usual assumption in regression analysis is that the variances of the error terms are constant across the data. Occasionally, this assumption of homoscedasticity on the variance is violated; and the data generated from real world applications exhibit heteroscedasticity. The practical importance of detecting heteroscedasticity in regression analysis is widely recognized in many applications because efficient inference for the regression function requires unequal variance to be taken into account. The goal of this thesis is to propose new testing procedures to assess the adequacy of fitting parametric variance function in heteroscedastic regression models. The proposed tests are established in Chapter 2 using certain minimized L[subscript]2 distance between a nonparametric and a parametric variance function estimators. The asymptotic distribution of the test statistics corresponding to the minimum distance estimator under the fixed model and that of the corresponding minimum distance estimators are shown to be normal. These estimators turn out to be [sqrt]n consistent. The asymptotic power of the proposed test against some local nonparametric alternatives is also investigated. Numerical simulation studies are employed to evaluate the nite sample performance of the test in one dimensional and two dimensional cases. The minimum distance method in Chapter 2 requires the calculation of the integrals in the test statistics. These integrals usually do not have a tractable form. Therefore, some numerical integration methods are needed to approximate the integrations. Chapter 3 discusses a nonparametric empirical smoothing lack-of-fit test for the functional form of the variance in regression models that do not involve evaluation of integrals. empirical smoothing lack-of-fit test can be treated as a nontrivial modification of Zheng (1996)'s nonparametric smoothing test and Koul and Ni (2004)'s minimum distance test for the mean function in the classic regression models. The asymptotic normality of the proposed test under the null hypothesis is established. Consistency at some fixed alternatives and asymptotic power under some local alternatives are also discussed. Simulation studies are conducted to assess the nite sample performance of the test. The simulation studies show that the proposed empirical smoothing test is more powerful and computationally more efficient than the minimum distance test and Wang and Zhou (2006)'s test.

Knowledge of the lane that a target is located in is of particular interest in on-road surveillance and target tracking systems. We formulate the problem and propose two approaches for on-road target estimation with lane tracking. The first approach for lane tracking is lane identification based ona Hidden Markov Model (HMM) framework. Two identifiers are developed according to different optimality goals of identification, i.e., the optimality for the whole lane sequence and the optimality of the current lane where the target is given the whole observation sequence. The second approach is on-road target tracking with lane estimation. We propose a 2D road representation which additionally allows to model the lateral motion of the target. For fusion of the radar and image sensor based measurement data we develop three, IMM-based, estimators that use different fusion schemes: centralized, distributed, and sequential. Simulation results show that the proposed two methods have new capabilities and achieve improved estimation accuracy for on-road target tracking.

No description available.

Les appareils d'acquisition d'image 3D sont désormais omniprésents dans plusieurs domaines scientifiques, dont l'imagerie biomédicale, la science des matériaux ou encore l'industrie. La plupart de ces appareils (IRM, scanners à rayons X, micro-tomographes, microscopes confocal, PET scans) produisent un ensemble de données organisées sur une grille régulière que nous nommerons des données digitales, plus couramment des pixels sur des images 2D et des voxels sur des images 3D. Lorsqu'elles sont bien récupérées, ces données approchent la géométrie de la forme capturée (comme des organes en imagerie biomédicale ou des objets dans l'ingénierie). Dans cette thèse, nous nous sommes intéressés à l'extraction de la géométrie sur ces données digitales, et plus précisément, nous nous concentrons à nous approcher des quantités géométriques différentielles comme la courbure sur ces objets. Ces quantités sont les ingrédients critiques de plusieurs applications comme la reconstruction de surface ou la reconnaissance, la correspondance ou la comparaison d'objets. Nous nous focalisons également sur les preuves de convergence asymptotique de ces estimateurs, qui garantissent en quelque sorte la qualité de l'estimation. Plus précisément, lorsque la résolution de l'appareil d'acquisition est augmenté, notre estimation géométrique est plus précise. Notre méthode est basée sur les invariants par intégration et sur l'approximation digitale des intégrations volumiques. Enfin, nous présentons une méthode de classification de la surface, qui analyse les données digitales dans un système à plusieurs échelles et classifie les éléments de surface en trois catégories : les parties lisses, les parties planes, et les parties singulières (discontinuités de la tangente). Ce type de détection de points caractéristiques est utilisé dans plusieurs algorithmes géométriques, comme la compression de maillage ou la reconnaissance d'objet. La stabilité aux paramètres et la robustesse au bruit sont évaluées en fonction des méthodes de la littérature. Tous nos outils pour l'analyse de données digitales sont appliqués à des micro-structures de neige provenant d'un tomographe à rayons X, et leur intérêt est évalué et discuté. / 3D image acquisition devices are now ubiquitous in many domains of science, including biomedical imaging, material science, or manufacturing. Most of these devices (MRI, scanner X, micro-tomography, confocal microscopy, PET scans) produce a set of data organized on a regular grid, which we call digital data, commonly called pixels in 2D images and voxels in 3D images. Properly processed, these data approach the geometry of imaged shapes, like organs in biomedical imagery or objects in engineering. In this thesis, we are interested in extracting the geometry of such digital data, and, more precisely, we focus on approaching geometrical differential quantities such as the curvature of these objects. These quantities are the critical ingredients of several applications like surface reconstruction or object recognition, matching or comparison. We focus on the proof of multigrid convergence of these estimators, which in turn guarantees the quality of estimations. More precisely, when the resolution of the acquisition device is increased, our geometric estimates are more accurate. Our method is based on integral invariants and on digital approximation of volumetric integrals. Finally, we present a surface classification method, which analyzes digital data in a multiscale framework and classifies surface elements into three categories: smooth part, planar part, and singular part (tangent discontinuity). Such feature detection is used in several geometry pipelines, like mesh compression or object recognition. The stability to parameters and the robustness to noise are evaluated with respect to state-of-the-art methods. All our tools for analyzing digital data are applied to 3D X-ray tomography of snow microstructures and their relevance is evaluated and discussed.

Como tentativa para compensar a ausência de resposta, aplicou-se o estimador ponderado por pesos amostrais nos dados de um inquérito domiciliar que registrou uma taxa global de resposta igual a 79,10 por cento . O procedimento procurou viabilizar a aplicação do ajuste ao nível dos elementos, usando os pesos obtidos a partir da taxa diferencial de resposta verificada na amostra composta pelas famílias. Fixado o número de cômodos do domicílio como a variável critério para a formação das classes ponderadas, calcularam-se as médias ajustadas e suas variâncias para o peso e a estatura dos menores de 19 anos, usando-se as estimativas calculadas na amostra constituída pelos elementos pertencentes às famílias que efetivamente responderam ao inquérito. A consistência dos resultados obtidos sugere que estudos devem ser desenvolvidos a fim de buscar soluções que minimizem as pressuposições necessárias à aplicação do procedimento e determinem níveis de abrangência que possam ser considerados satisfatórios. / The weighting adjustment by sample weights was applied on the data from a survey sampling with a total response rate of 79,10 per cent , in order to compensate for the unit nonresponse. The weighting factors were gotten by the differential response rate calculated on the household sample to facilitate the application procedure. The variable used to define the weighting classes was the number of rooms of the dwellings. Also, the adjusted means and their variances were calculaled for weight and height of persons with ages under 19 years, using the measures obtained from the same age group individuals related to the respondent households. The consistency of the results support the sugestion that more research has to be done to search for procedures that will minimize the necessary assumptions that underlie them and that can assure wider application levels.

Atualmente, otimizar uma arquitetura ou um sistema de software não significa, necessariamente, aumentar o seu desempenho computacional. Devido a popularização de sistemas embutidos energizados por bateria, um item de grande importância a ser otimizado é o consumo de energia. De forma a obedecer às restrições de consumo, pesquisadores têm concentrado seus esforços na criação de ferramentas que possibilitam a modelagem, a otimização e a estimação do consumo de energia. Nos últimos anos, FPGAs têm apresentado um grande desenvolvimento nos quesitos densidade, velocidade e capacidade de armazenamento. Essas características tornaram possível a construção de sistemas complexos formados por um ou mais processadores soft-core. Esse tipo de processador permite uma personalização detalhada de suas características arquiteturais, possibilitando uma melhor adequação às restrições de tempo e espaço em um projeto. O objetivo deste trabalho é construir um estimador de potência para softwares que têm como alvo o processador soft-core Nios II da Altera, permitindo saber com antecedência quanta energia será consumida devido à execução de programas e aplicações de robótica móvel. O modelo implementado neste trabalho foi testado com vários benchmarks padronizados e os resultados obtidos provaram ser bastante adequados para estimar a energia consumida por um programa, obtendo erros de estimação máximos de 4,78% / Nowadays, optimization of hardware and software systems does not necessarily mean increasing their computational performance. Due to the popularization of battery-operated embedded systems, energy comsumption has become a very critical issue. Several tools have been created to model, optimize, and estimate energy consumption, allowing power constraints to be achieved. Lately, FPGAs have presented great advancements on density, speed and storage capacity. Such characteristics made possible the implementation of complex systems comprising one or more soft-core processors. This kind of processors allows detailed customization of its architectural features, enabling timinig, and area constraints of a design to be reached. The aim of this work is to build a power estimator to predict the energy comsumption of a software running on the Altera Nios II soft-core processor. The implemented estimation model presented on this dissertation has been tested with several standard benchmarks and the results obtained have proven to be suitable for estimating the energy consumption of a software with a maximum error of 4.78%

Growing demand and concern over climate change are key drivers for renewable sources of electricity and grid modernization. Grid modernization, or the so called smart grid, not only enables renewable sources but also opens the door to new applications with far-reaching impacts such as preventing or restoring outages (self-healing capabilities), and enabling consumers to have greater control over their electricity consumption and to actively participate in the electricity market. According to the Electric Power Research Institute (EPRI), one of the biggest challenges facing smart grid deployment is related to the cyber security of the systems. The current cyber-security landscape is characterized by rapidly evolving threats and vulnerabilities that pose challenges for the reliability, security, and resilience of the electricity sector. Power system state estimators (PSSE) are critical tools for grid reliability, under a system observable scenario, they allow power flow optimization and detection of incorrect data. In this work cyber-attacks are modeled as malicious data injections on system measurements, parameters and topology. The contributions of this work are twofold. First, a model for cyber-attack as a false data injection detection and identification is presented. The presented model considers the minimization of the composed measurement error while applying the Lagrangian relaxation. The presented contribution, enables false data injection attacks detection even if this belongs to the subspace spanned by the columns of the Jacobian matrix and in network areas with low measurement redundancy Second, state-of-the-art solutions consider correction of parameters or topology when measurements are free of error. However, how may one correct measurements if parameters or topology might be simultaneously in error? To solve this problem, a relaxed model is presented and solved iteratively in a continuous manner. Once identified and detected, cyber-attacks in parameters, topology and measurements are corrected. The proposed solution is based on a Taylor series relaxed, composed normalized error (CNE) hybrid approach with Lagrange multipliers. Validation is made on the IEEE-14 and IEEE-57 bus systems. Comparative results highlight the proposed methodology’s contribution to the current state-of-the-art research on this subject. Providing mitigation, response and system recovery capabilities to the state estimator with reduced computational burden, the proposed model and methodology have strong potential to be integrated into SCADA state estimators for real-world applications. / O aumento da demanda e a preocupação com as mudanças climáticas são importantes motivadores para as fontes de energia renováveis e a modernização da rede elétrica. A modernização da rede elétrica inteligentes (REI) ou smart grid, não somente possibilita as fontes de energia renováveis mas também abre portas à novas aplicações de grande impacto como a prevenção e restauração automática de falhas e a possibilidade dos consumidores terem grande controle sobre o consumo de eletricidade e atuação participativa no mercado de energia. De acordo com o Instituto Norte Americano de Pesquisas do Setor Elétrico, um dos principais desafios a ser enfrentado no desenvolvimento das REIs é relacionado a segurança cibernética dos sistemas. O cenário da segurança cibernética atual é caracterizado pela rápida evolução dos riscos e vulnerabilidades que impõe desafios para a confiabilidade, segurança e resiliência do setor elétrico. Neste contexto, estimadores de estado do sistema de potência são ferramentas críticas para a confiabilidade da rede, sob um cenário de observabilidade do sistema eles possibilitam o fluxo de potência do sistema e a análise de dados incorretos. Neste trabalho, ataques cibernéticos são modelados como injeção de dados incorretos em medidas, parâmetros e topologia do sistema. A metodologia proposta possibilita detecção de ataques mesmo se eles pertencerem ao subespaço ortogonal formado pelas colunas da matriz Jacobiana e em áreas do sistema com reduzida redundância de medidas. A solução proposta pelo estado da arte considera correções em parâmetros ou topologia quando medidas estão livres de erros. Porém, como pode-se corrigir medidas se parâmetros ou a topologia estão simultaneamente com erros? Para resolver este problema um modelo relaxado é proposto e resolvido iterativamente. Assim que detectado e identificado, ataques cibernéticos em parâmetros, topologia e/ou medidas são corrigidos. As contribuições específicas do trabalho são: cálculo do desvio padrão para pseudomedidas (iguais à zero) e medidas de baixa magnitude baseado em medidas correlatas e propriedades da covariância; modelo baseado em relaxação lagrangiana e erro composto de medida para identificação e detecção de ataques cibernéticos; estratégia hibrida de relaxamento iterativo (EHRI) para correção de ataque cibernético em parâmetros da rede de modo contínuo e com reduzido esforço computacional e metodologia baseada em ciclo holístico de resiliência para estimadores de estado sob ataques cibernéticos simultâneos em parâmetros, topologia e medidas. A validação é feita através dos sistemas de teste do IEEE de 14 e 57 barras, testes comparativos elucidam as contribuições da metodologia proposta ao estado da arte nesta área de pesquisa. Trazendo as capacidades de mitigação, resposta e recuperação ao estimador de estado com esforço computacional reduzido, o modelo e metodologia propostos tem grande potencial de ser integrado em SCADAs para aplicação em casos reais.

A maior presença de correntes harmônicas no sistema de distribuição, principalmente devido à geração distribuída, tem chamado atenção sobre suas possíveis consequências. O trabalho apresenta um método para a avaliação de harmônicas em um sistema elétrico através de um estimador de estados. A proposta é um método de supervisão da rede de distribuição utilizando o menor número de medidores possível. Isso foi feito identificando topologias de rede que viabilizam o uso de pseudomedidas no lugar de medidores. O método é aplicado a um estudo de caso baseado no modelo IEEE 13 barras e os resultados do estimador de estados foram comparados a uma simulação. Também é feita uma análise de sensibilidade do código, observando os resultados quando se adicionam erros sobre as medidas e sobre os parâmetros das linhas do sistema. / The growth of harmonic currents in distribution system, mainly due the distributed generation, is calling attention of the specialists to its possible consequences. This work presents a method to assessment of harmonics in an electric power system through a state estimator. The proposal is a method to monitor the distribution network using as few measurement devices as possible. It was performed identifying network topologies where a pseudomeasurement can replace a measurement device. The method was applied to a study case based on the IEEE 13 buses model and its results were compared to a simulation. A sensitivity analysis of the code also was performed, errors were added to measurements and lines parameters to assess the errors in the state estimator results.