Dissertations / Theses on the topic 'Estimation par interval'
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Rabehi, Djahid. "Estimation par Intervalles des Systèmes Cyber-physiques." Thesis, Orléans, 2019. http://www.theses.fr/2019ORLE3038.
Full textCyber-Physical Systems are smart integrations of computation, networking, and physical processes. In this thesis, we deal with interval observers for cyber-physical systems in which the continuous-time physical systems are estimated and monitored using discrete-time data transmitted over network.The contributions of the presented material are threefold: (i) we design an interval impulsive observer for continuous-time linear systems with sporadically available measurements; (ii) we propose a finite L1-gain event-triggered interval impulsive observer for continuous-time linear systems, in which we develop a co-design procedure to simultaneously design the observer gain and the event-triggering condition; (iii) using the interval impulsive observer, we develop a secure estimation strategy for multi-output systems under cyber-attacks
Mohammedi, Irryhl. "Contribution à l’estimation robuste par intervalle des systèmes multivariables LTI et LPV : Application aux systèmes aérospatiaux." Electronic Thesis or Diss., Bordeaux, 2024. http://www.theses.fr/2024BORD0142.
Full textThe work of this thesis aims at developing new approaches based on a new particular class of state estimators, the so-called interval or ensemble filters.Like the class of interval observers, the objective is to estimate, in a guaranteed way, the upper and lower bounds of the states of a system, at each time instant.The proposed approach is based on the theory of monotonic systems and on the knowledge of the domain of membership, supposedly bounded, of the uncertainties of the system, such as disturbances, noise and bias of sensors, etc.The key element of the proposed approach is to use a filter structure advantage, rather than an observer-based structure (relying only on a dynamic structure of the studied system).The synthesis of the filter parameters is based on the resolution of a constrained optimization problem of linear and bilinear matrix inequalities (LMI and BMI) allowing to guarantee simultaneously the existence conditions of the filter as well as a performance level, either in an energy context for LTI systems, or in an amplitude context or in a mixed energy/amplitude context for LPV systemsThe proposed synthesis methodology is illustrated on an academic example and is compared with other existing methods in the literature. Finally, the methodology is applied to the case of attitude and acceleration control of a satellite, under realistic simulation conditions
Filali, Rayen. "Estimation et commande robustes de culture de microalgues pour la valorisation biologique de CO2." Phd thesis, Supélec, 2012. http://tel.archives-ouvertes.fr/tel-00765421.
Full textKharkovskaia, Tatiana. "Conception d'observateurs par intervalle pour les systèmes à paramètres distribués avec incertitudes." Thesis, Ecole centrale de Lille, 2019. http://www.theses.fr/2019ECLI0019.
Full textThis work presents new results on interval state estimation for uncertain distributed systems, the state of which has an infinite dimension and is described by partial (PDEs) or (FDEs) functional differential equations. An interval observer evaluates at each time instant a set of admissible values for the state (an interval), consistently with the measured output. The design is based on the positive systems theory. Chapters 2 and 3 focus on an interval observer design for a parabolic PDE with Dirichlet boundary conditions. The method in Chapter 2 is based on a finite-element Galerkin approximation, the interval inclusion of the state is calculated using the error estimates of the approximation. Chapter 3 presents an interval observer in the form of PDEs without Galerkin projection. In both chapters, the obtained interval estimates are applied to the design of a dynamic output feedback stabilizing controller. Chapter 4 deals with a second-order delay differential equation with uncertainties corresponding, for instance, to a mechanical system with delayed position measurements, which has form of an FDE. The proposed method contains two consecutive interval observers. The first one estimates, at each instant of time, the interval for the delay-free position using new delay-dependent conditions on positivity. Then, derived estimates of the position are used to design the second observer providing an interval for the velocity. All the obtained results are supported by numerical simulations. In particular, Chapter 2 includes experiments on the Black–Scholes model
Zammali, Chaima. "Robust state estimation for switched systems : application to fault detection." Electronic Thesis or Diss., Sorbonne université, 2020. http://www.theses.fr/2020SORUS124.
Full textThis thesis deals with state estimation and fault detection for a class of switched linear systems. Two interval state estimation approaches are proposed. The first one is investigated for both continuous and discrete-time linear parameter varying switched systems subject to measured polytopic parameters. The second approach is concerned with a new switching signal observer, combining sliding mode and interval techniques, for a class of switched linear systems with unknown input. State estimation remains one of the fundamental steps to deal with fault detection. Hence, robust solutions for fault detection are considered using set-membership theory. Two interval techniques are achieved to deal with fault detection for discrete-time switched systems. First, a commonly used interval observer is designed based on an L∞ criterion to obtain accurate fault detection results. Second, a new interval observer structure (TNL structure) is investigated to relax the cooperativity constraint. In addition, a robust fault detection strategy is considered using zonotopic and ellipsoidal analysis. Based on optimization criteria, the zonotopic and ellipsoidal techniques are used to provide a systematic and effective way to improve the accuracy of the residual boundaries without considering the nonnegativity assumption. The developed techniques in this thesis are illustrated using academic examples and the results show their effectiveness
Khemane, Firas. "Estimation fréquentielle par modèle non entier et approche ensembliste : application à la modélisation de la dynamique du conducteur." Thesis, Bordeaux 1, 2011. http://www.theses.fr/2010BOR14282/document.
Full textThis thesis deals with system identification and modeling of fractional transfer functions using bounded and uncertain frequency responses. Therefor, both of fractional differentiation and integration definitions are extended into intervals. Set membership approaches are then applied to estimate coefficients and derivative orders as intervals. These methods are applied to estimate certain Linear Time Invariant systems (LTI), uncertain LTI systems and Linear Parameter Varying systems (LPV). They are notably adopted to model driver's dynamics, since most of studies on one or several individuals shave shown that the collected reactions are not identical and are varying from an experiment to another
Dinh, Ngoc Thach. "Observateur par intervalles et observateur positif." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112335/document.
Full textThis thesis presents new results in the field of state estimation based on the theory of positive systems. It is composed of two separate parts. The first one studies the problem of positive observer design for positive systems. The second one which deals with robust state estimation through the design of interval observers, is at the core of our work.We begin our thesis by proposing the design of a nonlinear positive observer for discrete-time positive time-varying linear systems based on the use of generalized polar coordinates in the positive orthant. For positive systems, a natural requirement is that the observers should provide state estimates that are also non-negative so they can be given a physical meaning at all times. The idea underlying the method is that first, the direction of the true state is correctly estimated in the projective space thanks to the Hilbert metric and then very mild assumptions on the output map allow to reconstruct the norm of the state. The convergence rate can be controlled.Later, the thesis is continued by studying the so-called interval observers for different families of dynamic systems in continuous-time, in discrete-time and also in a context "continuous-discrete" (i.e. a class of continuous-time systems with discrete-time measurements). Interval observers are dynamic extensions giving estimates of the solution of a system in the presence of various type of disturbances through two outputs giving an upper and a lower bound for the solution. Thanks to interval observers, one can construct control laws which stabilize the considered systems
Li, Qiaochu. "Contribution à la planification d'expériences, à l'estimation et au diagnostic actif de systèmes dynamiques non linéaires : application au domaine aéronautique." Thesis, Compiègne, 2015. http://www.theses.fr/2015COMP2231/document.
Full textIn this work, we will study the uncertainty integration problem in a bounded error context for the dynamic systems, whose input and the initial state have to be optimized so that some other operation could be more easily and better obtained. This work is consisted of 6 chapters : the chapter 1 is an introduction to the general subject which we will discuss about. The chapter 2 represents the basic tools of interval analysis.The chapter 3 is dedicated to state estimation and parameter estimation. We explain at the first, how to solve the ordinary differential equation using interval analysis, which will be the basic tool for the state estimation problem given the initial condition of studied systems. On the other ride, we will look into the parameter estimation problem using interval analysis too. Based on a simple hypothesis over the uncertain variable, we calculate the system's parameter in a bounded error form, considering the operation of intervals as the operation of sets. Guaranteed results are the advantage of interval analysis, but the big time consumption is still a problem for its popularization in many non linear estimation field. We present our founding techniques to accelerate this time consuming processes, which are called contractor in constraint propagation field. At the end of this chapter, différent examples will be the test proof for our proposed methods.Chapter 4 presents the searching for optimal input in the context of interval analysis, which is an original approach. We have constructed several new criteria allow such searching. Some of them are intuitive, the other need a theoretical proof. These criteria have been used for the search of optimal initial States and le better parameter estimation results. The comparisons are done by using multiple applications and the efficiency is proved by evidence.In chapter 5, we applied the approaches proposed above in diagnosis by state estimation and parameter estimation. We have developed a complete procedure for the diagnosis. The optimal input design has been reconsidered in an active diagnosis context. Both state and parameter estimation are implemented using an aeronautical application in literature.The last chapter given a brief summary over the realized subject, some further research directions are given in the perspective section.All the algorithms are written in C/C++ on a Linux based operation system
Boulanger, Xavier. "Modélisation du canal de propagation Terre-Espace en bandes Ka et Q/V : synthèse de séries temporelles, variabilité statistique et estimation de risque." Thesis, Toulouse, ISAE, 2013. http://www.theses.fr/2013ESAE0009/document.
Full textNowadays, C and Ku bands used for fixed SATCOM systems are totally congested. However, the demand of the end users for high data rate multimedia services is increasing. Consequently, the use of higher frequency bands (Ka: 20 GHz and Q/V 40/50 GHz) is under investigation. For frequencies higher than 5 GHz, radiowave propagation is strongly affected by tropospheric attenuation. Among the different contributors, rain is the most significant. To compensate the deterioration of the propagation channel, Fade Mitigation Techniques (FMT) are used. The lack of experimental data needed to optimize the real-time control loops of FMT leads tothe use of rain attenuation and total attenuation time series synthesizers. The manuscript is a compilation of five articles. The first contribution is dedicated to the temporal modelling of total impairments. The second article aims at providing significant improvements on the rain attenuation time series synthesizer recommended by ITU-R. The last three contributions are a critical analysis and a modelling of the variability observed on the 1st order statistics used to validate propagation channel models. The variance of the statistical estimator of the complementary cumulative distribution functions of rainfall rate and rain attenuation is highlighted. A worldwide model parameterized in compliance with propagation measurements is proposed. It allows the confidence intervals to be estimated and the risk on a required availability associated with a given propagation margin prediction to be quantified. This approach is extended to the variability of joint statistics. It allows the impact of site diversity techniques on system performances at small scale (few kms) and large scale (few hundred of kms) to be evaluated
Dandach, Hoda. "Prédiction de l'espace navigable par l'approche ensembliste pour un véhicule routier." Thesis, Compiègne, 2014. http://www.theses.fr/2014COMP1892/document.
Full textIn this thesis, we aim to characterize a vehicle stable state domain, as well as vehicle state estimation, using interval methods.In the first part of this thesis, we are interested in the intelligent vehicle state estimation.The Bayesian approach is one of the most popular and used approaches of estimation. It is based on the calculated probability of the density function which is neither evident nor simple all the time, conditioned on the available measurements.Among the Bayesian approaches, we know the Kalman filter (KF) in its three forms(linear, non linear and unscented). All the Kalman filters assume unimodal Gaussian state and measurement distributions. As an alternative, the Particle Filter(PF) is a sequential Monte Carlo Bayesian estimator. Contrary to Kalman filter,PF is supposed to give more information about the posterior even when it has a multimodal shape or when the noise follows non-Gaussian distribution. However,the PF is very sensitive to the imprecision due by bias or noise, and its efficiency and accuracy depend mainly on the number of propagated particles which can easily and significantly increase as a result of this imprecision. In this part, we introduce the interval framework to deal with the problems of the non-white biased measurements and bounded errors. We use the Box Particle Filter (BPF), an estimator based simultaneously on the interval analysis and on the particle approach. We aim to estimate some immeasurable state from the vehicle dynamics using the bounded error Box Particle algorithm, like the roll angle and the lateral load transfer, which are two dynamic states of the vehicle. BPF gives a guaranteed estimation of the state vector. The box encountering the estimation is guaranteed to encounter thereal value of the estimated variable as well.In the second part of this thesis, we aim to compute a vehicle stable state domain.An algorithm, based on the set inversion principle and the constraints satisfaction,is used. Considering the longitudinal velocity and the side slip angle at the vehicle centre of gravity, we characterize the set of these two state variables that corresponds to a stable behaviour : neither roll-over nor sliding. Concerning the roll-over risk,we use the lateral transfer ratio LTR as a risk indicator. Concerning the sliding risk, we use the wheels side slip angles. All these variables are related geometrically to the longitudinal velocity and the side slip angle at the centre of gravity. Using these constraints, the set inversion principle is applied in order to define the set ofthe state variables where the two mentioned risks are avoided. The algorithm of Sivia is implemented. Knowing the vehicle trajectory, a maximal allowed velocityon every part of this trajectory is deduced
Amri, Mohamed-Hédi. "Fusion ensembliste de donn´ees pour la surveillance des personnes d´ependantes en habitat intelligent." Thesis, Orléans, 2015. http://www.theses.fr/2015ORLE2030/document.
Full textOur research work is a part of the project FUI 14 FEDER Collectivités E-monitor’âge. This project takes place within the framework of Ambient Assisted Living (AAL) which aims to improve the safety and the comfort of elderly people living in smart nursing homes. This work aims to monitor the activities of elderly persons using information from different sensors. The ADL (Activities of Daily Living) are used to evaluate the ability of the person to perform on their own a selection of the activities which are essential for an independent living in the everyday life. Generally, process knowledge and measurements coming from sensors are prone to indeterminable noise. In our work, we suppose that these errors are unknown but bounded. Taking into account this hypothesis, we show how to solve the estimation issue using set-membership computations techniques. Our algorithm, based on set-membership approach, consists of two steps. The prediction step, based on the use of a random walk mobility with minimum assumptions (maximum speed of moving), employs the previous state estimate to provide the prediction zone where the person may be located. The correction step uses the informations coming from the sensors to refine this predicted zone. This step uses a relaxed constraints propagation technique, q-relaxed intersection, to deal with faulty measurements. This proposed method allows us to compute the uncertainty domain for the reconstructed localization of moving targets as dealing with outliers
Guerine, Ahmed. "Contribution à l'étude du comportement dynamique d'un système d'engrenage en présence d'incertitudes." Thesis, Rouen, INSA, 2016. http://www.theses.fr/2016ISAM0013/document.
Full textIn the present work, the dynamic behavior of a gear system with uncertain parameters is studied. One of the principal hypotheses in the use of methods for taking into account uncertainties is that the model is deterministic, that is to say that parameters used in the model have a defined and fixed value. Furthermore, the knowledge of variation response of a gear system involving damping coefficients, mesh stiffness, friction coefficient, assembly defect, manufacturing defect or the input blades in the case of wind turbine is essential. In the first part, we investigate the dynamic response of a gear system with uncertain parameters modeled as random variables. A Monte Carlo simulation, a perturbation method and a polynomial chaos method are carried out. In the second part, two approaches are used to analyze the dynamic behavior of a wind turbine gear system : the probabilistic approach and the interval analysis method. The objective is to compare the two approaches to define their advantages and disadvantages in terms of precision and computation time
Silva, Paulo Henrique Ferreira da. "Multivariate Copula-based SUR Tobit Models : a modified inference function for margins and interval estimation." Universidade Federal de São Carlos, 2015. https://repositorio.ufscar.br/handle/ufscar/7226.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
In this thesis, we extend the analysis of multivariate Seemingly Unrelated Regression (SUR) Tobit models by modeling their nonlinear dependence structures through copulas. The capability in coupling together the diferent - and possibly non-normal - marginal distributions allows the exible modeling for the SUR Tobit models. In addition, the ability to capture the tail dependence of the SUR Tobit models where some data are censored (e.g., in econometric analysis, clinical essays, wide range of political and social phenomena, among others, data are commonly left-censored at zero point, or right-censored at a point d > 0) is another useful feature of copulas. Our study proposes a modified version of the (classical) Inference Function for Margins (IFM) method by Joe & Xu (1996), which we refer to as MIFM method, to obtain the (point) estimates of the marginal and copula association parameters. More specifically, we use a (frequentist) data augmentation technique at the second stage of the IFM method (the first stage of the MIFM method is equivalent to the first stage of the IFM method) to generate the censored observations and then estimate the copula parameter. This procedure (data augmentation and copula parameter estimation) is repeated until convergence. Such modification at the second stage of the usual method is justified in order to obtain continuous marginal distributions, which ensures the uniqueness of the resulting copula, as stated by Sklar (1959)'s theorem; and also to provide an unbiased estimate of the copula association parameter (the IFM method provides a biased estimate of the copula parameter in the presence of censored observations in the margins). Since the usual asymptotic approach, that is the computation of the asymptotic covariance matrix of the parameter estimates, is troublesome in this case, we also propose the use of resampling procedures (bootstrap methods, like standard normal and percentile by Efron & Tibshirani (1993), and basic bootstrap by Davison & Hinkley (1997)) to obtain con_dence intervals for the copula-based SUR Tobit model parameters.
Nesta tese de doutorado, consideramos os chamados modelos SUR (da expressão Seemingly Unrelated Regression) Tobit multivariados e estendemos a análise de tais modelos ao empregar funções de cópula para modelar estruturas com dependência não linear. As cópulas, dentre outras características, possuem a importante habilidade (vantagem) de capturar/modelar a dependência na(s) cauda(s) do modelo SUR Tobit em que alguns dados são censurados (por exemplo, em análise econométrica, ensaios clínicos e em ampla gama de fenômenos políticos e sociais, dentre outros, os dados são geralmente censurados à esquerda no ponto zero, ou à direita em um ponto d > 0 qualquer). Neste trabalho, propomos uma versão modificada do método clássico da Inferência para as Marginais (IFM, da expressão Inference Function for Margins), originalmente proposto por Joe & Xu (1996), a qual chamamos de MIFM, para estimação (pontual) dos parâmetros do modelo SUR Tobit multivariado baseado em cópula. Mais especificamente, empregamos uma técnica (frequentista) de ampliação de dados no segundo estágio do método IFM (o primeiro estágio do método MIFM é igual ao primeiro estágio do método IFM) para gerar as observações censuradas e, então, estimamos o parâmetro de dependência da cópula. Repetimos tal procedimento (ampliação de dados e estimação do parâmetro da cópula) até obter convergência. As razões para esta modificação no segundo estágio do método usual, são as seguintes: primeiro, construir/obter distribuições marginais contínuas, atendendo, então, ao teorema de unicidade da cópula resultante de Sklar (Sklar, 1959); e segundo, fornecer uma estimativa não viesada para o parâmetro da cópula (uma vez que o método IFM produz estimativas viesadas do parâmetro da cópula na presença de observações censuradas nas marginais). Tendo em vista a dificuldade adicional em calcular/obter a matriz de covariâncias assintótica das estimativas dos parâmetros, também propomos o uso de procedimentos de reamostragem (métodos bootstrap, tais como normal padrão e percentil, propostos por Efron & Tibshirani (1993), e básico, proposto por Davison & Hinkley (1997)) para a construção de intervalos de confiança para os parâmetros do modelo SUR Tobit baseado em cópula.
Tillet, Joris. "Safe localization and control of a towed sensor." Thesis, Brest, École nationale supérieure de techniques avancées Bretagne, 2021. http://www.theses.fr/2021ENTA0013.
Full textThe oceans’ exploration becomes more and more reachable, especially thanks to robotics progress. Applications for underwater robots are plentiful. In this thesis, we particularly focus on the search of wrecks, as the Cordelière, which sank in the Bay of Brest (France) in 1512. The proposed robotic system consists of towing a magnetometer likely to detect the ferromagnetic materials of the wreck. The sensor cannot be directly embedded because it is sensitive to the perturbations from the robot. This is why it is deported. Two issues are studied to approach this system. The first one is linked to the control of the magnetometer’s position, whereas we can only act on the towing robot. A feedback linearization method is used to design a controller. Then, this controller is validated under some state constraints by using tools from interval analysis. The second issue relates to underwater localization in a reliable manner. Ways to approach uncertainties and outliers gathered by acoustic sensors are studied. The interval analysis allows to obtain first results, and the fuzzy logic completes the approach by giving more suppleness in the prioritization of the constraints. Finally, some expérimentations are presented with different robots, and especially the localization of a ROV in a pool
Bahamyirou, Asma. "Sur les intervalles de confiance bayésiens pour des espaces de paramètres contraints et le taux de fausses découvertes." Mémoire, Université de Sherbrooke, 2015. http://hdl.handle.net/11143/6986.
Full textFlissak, Julia Caroline. "Análise do desenvolvimento intrapuparial de sarconesia chlorogaster (Wiedemann, 1830) (Diptera, calliphoridae) para estimativa de intervalo pós-morte (IPM)." reponame:Repositório Institucional da UFPR, 2017. http://hdl.handle.net/1884/46201.
Full textDissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências Biológicas, Programa de Pós-Graduação em Ciências Biológicas (Entomologia). Defesa: Curitiba, 20/02/2017
Inclui referências: 30-34
Área de concentração : Entomologia
Resumo: Sarconesia chlorogaster (Wiedemann, 1830) (Diptera, Calliphoridae) é uma espécie de importância forense endêmica da região Sul que possui a morfologia dos estágios imaturos descrita e os tempos de desenvolvimento em seis temperaturas já registrados na literatura. A duração de seu desenvolvimento pupal é cerca de 70% do tempo do desenvolvimento total do imaturo. Portanto, em um contexto forense, as mudanças que acontecem nesse estágio, se refinadas, podem fornecer maior acurácia e confiabilidade ao cálculo do IPM mínimo usando imaturos de S. chlorogaster. Considerando a importância desta espécie, o objetivo principal deste trabalho foi identificar e descrever as mudanças morfológicas temporais do desenvolvimento das pupas de S. chlorogaster. Para isso, foi acompanhado o desenvolvimento de S. chlorogaster em dieta artificial em duas temperaturas constantes (20 e 25ºC). A partir do momento em que a larva de terceiro instar se enterrou, foram mortas e fixadas 10 pupas a cada oito (8) horas. De cada uma das 10 pupas, a morfologia externa foi descrita e fotografada, a cada oito (8) horas, durante às 416 horas que durou o estágio de pupa. Foram definidos, baseado em caracteres morfológicos, sete fases de desenvolvimento intrapuparial, pupariação, apólise larva- pupa, pupa criptocefálica, pupa fanerocefálica, apólise adulto-pupa, adulto farado e emergência. Das 45 características descritas morfologicamente, 15 são potencialmente informativas para estimar a idade de S. chlorogaster. De maneira geral, o formato do corpo (presença ou ausência de tagmatização), a coloração geral, a presença visível do gancho do cefaloesqueleto (porção da mandíbula), os apêndices torácicos, a mudança na coloração dos olhos e a formação das cerdas são caracteres que podem ser usados para definir idades específicas. Com estes resultados, é possível estimar o intervalo pós-morte de um corpo, utilizando características morfológicas intrapupariais. A descrição detalhada, que aumenta o grau de confiabilidade, derivada de uma técnica de análise morfológica de rotina, tende a permitir uma utilização mais ampla e confiável dessas informações para a estimativa do IPM. Palavras-chaves: Entomologia forense, morfologia interna, moscas necrófagas
Abstract: Sarconesia chlorogaster (Wiedemann, 1830) (Diptera, Calliphoridae) is a key forensic species endemic to the Southern region which has the immature stages morphology described and the development larval rate at six temperatures estimated. The duration of the pupal stage is about 70% of the time of total immature development. Thus, in a forensic context, changes occuring at this stage, if refined, can add accuracy and reliability to estimates of the minimum IPM using immature S. chlorogaster. Considering the importance of S. chlorogaster, the main objective of this work was to identify and to describe the temporal changes in the intrapupal development of S. chlorogaster. The intrapupal development were described for immatures reared in artificial diet in two constant temperatures (20 and 25ºC). From the moment the third instar larvae were buried, 10 pupae were killed and fixed in a eight (8) hours interval. From each of the 10 pupae, the external morphology was described and photographed during the 416 hours of the pupal stage. Based on morphological characters, seven stages of intrapuparial development, pupariation, larval-pupal apolysis, cryptocephalic pupa, phanerocephalic pupa, pupal-adult apolysis, pharate adult and emergence were defined. Of the 45 morphological diagnostic characteristics described, 15 are potentially informative to estimate S. chlorogaster age of. In general, the shape of the body (presence or absence of tagmatization), immature color, the presence of the mouth hook (portion of the jaw), the presence of thoracic appendages, the change in the color of the eyes and the formation of the bristles are characters useful to estimate specific ages. With these chronological changes in morphology it is possible to estimate the postmortem interval of a body, using intrapuparial morphology. A detailed morphological analysis, which enhances reliability and is based on routine techniques such as microscopy, tends to allow a wider use of this information to estimate post mortem interval. Keywords: Forensic entomology, internal morphology, necrophagous flies
Alhakim, Rshdee. "Optimisation des performances de réseaux de capteurs dynamiques par le contrôle de synchronisation dans les systèmes ultra large bande." Thesis, Grenoble, 2013. http://www.theses.fr/2013GRENT101/document.
Full textThe basic concept of Impulse-Radio UWB (IR-UWB) technology is to transmit and receive baseband impulse waveform streams of very low power density and ultra-short duration pulses (typically at nanosecond scale). These properties of UWB give rise to fine time-domain resolution, rich multipath diversity, low power and low cost on-chip implementation facility, high secure and safety, enhanced penetration capability, high user capacity, and potential spectrum compatibility with existing narrowband systems. Due to all these features, UWB technology has been considered as a feasible technology for WSN applications. While UWB has many reasons to make it a useful and exciting technology for wireless sensor networks and many other applications, it also has some challenges which must be overcome for it to become a popular approach, such as interference from other UWB users, accurate modelling of the UWB channel in various environments, wideband RF component (antennas, low noise amplifiers) designs, accurate synchronization, high sampling rate for digital implementations, and so on. In this thesis, we will focus only on one of the most critical issues in ultra wideband systems: Timing Synchronization
Beaumont, Guillaume. "Traitements correctifs des effets de décohérence acoustique induits par les fluctuations du milieu de propagation : algorithmes d’estimation bayésienne des directions d’arrivée en milieu fluctuant." Thesis, Ecole nationale supérieure Mines-Télécom Atlantique Bretagne Pays de la Loire, 2020. http://www.theses.fr/2020IMTA0200.
Full textThe purpose of these works is to propose new "physically informed" bayesian algorithms for DOA estimationin presence of random fluctuations due to the presence of internal waves in the propagation medium. First we will seehow to describe these fluctuations as a local perturbation of the celerity of the medium and then the impact of such waveson a propagated signal. In doing so, we are able to observe the corruption of this signal and to propose a statistical modelof this perturbation.After a state of the art of DOA estimation techniques in both constant an uncertain media, we will propose a modelizationof the fluctuations as a multiplicative phase noise following a multivariate gaussian distribution. Very close to thetheoretical model, this distribution allows us to develop the paSAMP algorithm, an Approximate Message Passingtechnique inspired form phase retrieval litterature which integrates this multiplicative phase noise model. In order to getcloser to the theoretical model, we propose to upgrade the phase noise prior using a multivariate Von Mises prior,allowing us to propose new bayesian methods for DOA estimation such as the VitAMin and the VistaBEM algorithms asextensions of resp. the paSAMP and the paVBEM algorithms. The first results on synthetic measurement considering aunivariate Von Mises phase noise seems are promising regarding the robustness of these algorithms to this new noisemodel.To conclude, we will see with the processing of real data from the ALMA campaign that it is possible to retrieve quantitiesfrom the theoretical model through signal statistics. Moreover, these quantities allow us to identify known phenomenon inthe propagation medium with only passive measurement. Such knowledge can then be use for tomography or as "smartinitialization" of the different algorithms
Tran, Tuan Anh. "Cadre unifié pour la modélisation des incertitudes statistiques et bornées : application à la détection et isolation de défauts dans les systèmes dynamiques incertains par estimation." Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30292/document.
Full textThis thesis deals with state estimation in discrete-time dynamic systems in the context of the integration of statistical and bounded error uncertainties. Motivated by the drawbacks of the interval Kalman filter (IKF) and its improvement (iIKF), we propose a filtering algorithm for linear systems subject to uncertain Gaussian noises, i.e. with the mean and covariance matrix defined by their membership to intervals. This new interval Kalman filter (UBIKF) relies on finding a punctual gain matrix minimizing an upper bound of the set of estimation error covariance matrices by respecting the bounds of the parametric uncertainties. An envelope containing all possible estimates is then determined using interval analysis. The UBIKF reduces not only the computational complexity of the set inversion of the matrices intervals appearing in the iIKF, but also the conservatism of the estimates. We then discuss different frameworks for representing incomplete or imprecise knowledge, including the cumulative distribution functions, the possibility theory and the theory of belief functions. Thanks to the last, a model in the form of a mass function for an uncertain multivariate Gaussian distribution is proposed. A box particle filter based on this theory is developed for non-linear dynamic systems in which the process noises are bounded and the measurement errors are represented by an uncertain Gaussian mass function. Finally, the UBIKF is applied to fault detection and isolation by implementing the generalized observer scheme and structural analysis. Through various examples, the capacity for detecting and isolating sensor/actuator faults of this tool is illustrated and compared to other approaches
Collet, Silvana Giacomini. "Métodos de pesquisa em nutrição de ruminantes: indicadores de índice fecal, n-alcanos e fibra em detergente ácido para estimativa do consumo e/ou fluxo intestinal de nutrientes." Universidade do Estado de Santa Catarina, 2011. http://tede.udesc.br/handle/handle/842.
Full textThe aim of this study was to validate the use of n-alkanes C31, C32 and C33 on estimates of intake and digestibility and assess the accuracy of the use of indicators and acid detergent fiber (ADF), compared to the lignin in the studies of duodenal flow of nutrients. In addition, was to studied the use of indicators of fecal content in the estimation of digestibility and forage intake in lambs receiving ryegrass green. Two assays were conducted digestibility "in vivo" with 16 days each (11 for adaptation and 5 collection). The treatments consisted of diets composed by Italian ryegrass (Lolium multiflorum Lam.), in two successive cycles of grazing (28 and 35 days regrowth). The n-alkane C33 showed fecal recovery close to 1,0 in both tests and was more accurate in predicting the digestibility of C31. The intestinal flows of dry matter (DM) estimated from the C31, FDA or lignin were similar. In addition, the flow estimates obtained by internal ADF and lignin markers proved closely associated (linear coefficient = 1,016, r2 = 0,809). In local validation of the use of n-alkanes to estimate the consumption pair C33: C32 showed better relationship with the observed dry matter intake, since it held the correction for recovery rate of fecal C32. For the study of fecal indicators index the best estimates of consumption of organic matter (IOM) were obtained when using the amounts excreted nitrogen (g / day) and neutral detergent fiber (NDF, g / day) associated with the content forage NDF (r² = 0,78, rsd = 0,095). In conclusion, estimates of consumption and / or digestibility using the technique of n-alkanes should be preceded by local validation tests, studies of the intestinal flow of nutrients the FDA can be used instead of the lignin and estimates of forage intake in sheep may be made depending on the amount of nitrogen excreted per day and NDF
Os objetivos deste trabalho foram validar o uso dos n-alcanos C31, C32 e C33 em estimativas de consumo e digestibilidade e avaliar a exatidão do uso destes indicadores e da fibra em detergente ácido (FDA), em comparação à lignina, nos estudos de fluxo duodenal de nutrientes. Além disso, foi estudado o uso de indicadores de índice fecal na estimativa da digestibilidade e do consumo de forragem em ovinos recebendo azevém anual verde. Foram conduzidos dois ensaios de digestibilidade in vivo com 16 dias de duração cada (11 de adaptação e 5 de coleta). Os animais utilizados foram oito ovinos machos, castrados, mantidos em gaiolas de metabolismo. A dieta fornecida foi composta exclusivamente de azevém anual (Lolium multiflorum Lam.) verde em dois ciclos de desenvolvimento (28 e 35 dias de rebrote). O n-alcano C33 apresentou recuperação fecal próxima de 1,0 em ambos os ensaios e se mostrou mais exato na predição da digestibilidade aparente que o C31. Os fluxos intestinais de matéria seca (MS) estimados a partir do C31, FDA ou lignina foram semelhantes. Além disso, as estimativas de fluxo obtidas pelos marcadores internos FDA e lignina se mostraram estreitamente associadas (coeficiente linear = 1,016; r2 = 0,809). Na validação local da utilização dos n-alcanos para estimativa do consumo o par C33:C32 mostrou melhor relação com o consumo de matéria seca observado, desde que realizada a correção pra taxa de recuperação fecal do C32. Para o estudo com indicadores de índices fecais as melhores estimativas do consumo de matéria orgânica (CMO) foram obtidas quando se utilizou as quantidades excretadas de nitrogênio (g/dia) e fibra em detergente neutro (FDN, g/dia) associados ao teor de FDN na forragem (r² = 0,78; dpr = 0,095). Em conclusão, estimativas do consumo e/ou digestibilidade aparente utilizando a técnica dos n-alcanos devem ser precedidas de ensaios de validação local; nos estudos do fluxo intestinal de nutrientes o FDA pode ser utilizado em substituição a lignina e estimativas do consumo de forragem em ovinos podem ser efetuadas em função da quantidade de nitrogênio e FDN excretados por dia
Ermida, Ana Catarina Marques. "Luminol : contributo para a estimativa do intervalo postmortem e de restos estilizados." Master's thesis, 2015. http://hdl.handle.net/10316/29793.
Full textPerante restos esqueletizados, identificados ou não, é de considerar a relevância da avaliação do tempo decorrido desde a morte do indivíduo, designado por intervalo postmortem (PMI1) Esta é uma das atribuições do antropólogo forense, saber há quanto tempo aconteceu a morte o que, obviamente, tem importantes consequências legais. O PMI é um dos principais desafios da Antropologia Forense, e vários são os métodos referenciados que o pretendem determinar, analisando factores intrínsecos e extrínsecos aos restos esqueletizados. É de salientar a necessidade de desenvolver uma técnica precisa, económica, fácil e reprodutível, que opere como teste presuntivo ou de orientação, com número de amostras considerável, que permita a significância estatística dos resultados obtidos. A reacção química que ocorre na presença de luminol, quimioluminescência, é assinalada como uma ferramenta de trabalho no sentido de avaliar o PMI, devido à sua elevada afinidade para a hemoglobina, que fica protegida no tecido ósseo pelo seu elevado conteúdo mineral, após o suprimento de sangue ter cessado postmortem. Esta técnica é já aplicada em locais de crime, na detecção de sangue, devido à grande sensibilidade da hemoglobina, podendo assim ser usada também em amostras de osso, segundo o mesmo princípio. O estudo da técnica do luminol surge como um método a investigar, com o objectivo de complementar os restantes métodos de avaliação do tempo decorrido desde a morte de restos esqueletizados já existentes, contribuindo para uma avaliação mais precisa do PMI e com a finalidade de permitir a distinção entre ossos de interesse médico-legal (em Portugal, amostras com menos de 15 anos) e ossos sem significado médico-legal (amostras com mais de 15 anos). 1 Foi decidida a utilização da sigla em inglês por uma questão de uniformização ix A amostra em estudo é constituída por 51 indivíduos de ambos os sexos, todos adultos, com idades entre os 20 e os 98 anos e com tempo decorrido desde a morte conhecido. O osso seleccionado foi a clavícula, com ausência de patologias ósseas. Os resultados obtidos na presente dissertação, com falsos positivos a atingir os 100%, descartam a possibilidade de, pelo menos sem a investigação de uma amostra de maiores dimensões e variedade, ser possível a distinção entre ossadas de pertinência forense e sem interesse médico-legal, para a realidade portuguesa. Contudo, a hipótese da reacção de quimioluminescência ser aplicada como teste presuntivo, sobretudo para restos esqueletizados fragmentados, mantém-se, com uma percentagem de falsos negativos de 22 a 25%. Comparando os dois tipos de escala empregues, embora mais subjectiva, a escala de 5 níveis apresenta resultados mais detalhados e descritivos, existindo duas categorias (“muito fraco positivo” e “forte positivo”) com assertividade de 100%, sendo, portanto, a mais indicada para uso futuro. Os resultados da estatística de Kappa, com valores compreendidos entre 0,79 e 0,97, revelaram confiança inter e intraobservador no teste de aplicação de luminol, como teste de presunção. A diagnose do PMI, baseada nos registos da reacção do luminol com a hemoglobina, não pode ser usada isoladamente. É necessária a interpretação das circunstâncias de recolha, das condições ambientais e também uma análise crítica dos dados resultantes do exame antropológico.
When facing skeletonized remains, identified or not, it is important to consider the relevance of assessing the time since death of the individual, known as postmortem interval (PMI). This is one of the duties of forensic anthropologists - knowing how long ago the death happened - which obviously has important legal consequences. The PMI is one of the main challenges of Forensic Anthropology, and several are the referenced methods that aim to determine it, considering intrinsic and extrinsic factors to the skeletonized remains. Therefore, it should be emphasized the need to develop a precise, economic, easy and reproducible technique, which will operate as a presumptive test or guidance, using a considerable number of samples, in order to allow the statistical significance of the results obtained. The chemical reaction that occurs in the presence of luminol, chemiluminescence, is noted as a work tool to evaluate the PMI. This is given by luminol’s high affinity for hemoglobin, which is secured in bone tissue by its high mineral content, after the blood supply ceases postmortem. This technique is already applied on blood detection at crime scenes, due to hemoglobin’s high sensitivity. So, according to the same principle, it can also be used in bone samples. The study of the luminol technic appears as a method to investigate, with the purpose of complementing the already used methods for the evaluation of the PMI of skeletonized remains. It contributes to a more accurate assessment of the PMI, in order to allow distinction between bones of forensic interest (in Portugal, samples with less than 15 years) and bones without medical-legal meaning (samples with more than 15 years). The test sample consists of 51 individuals of both sexes, all in adult age, between 20 and 98 years, with a known time since death. The selected bone was the collarbone, with no bone diseases. The results obtained in this thesis, with false positives achieving the 100%, rule out the possibility to distinguish between bones of forensic interest to the Portuguese reality, xi at least not without the investigation of a sample of larger dimensions and variety. However, the hypothesis of the chemiluminescent reaction being applied as a presumptive test is still applicable, especially for skeletonized fragmented remains, since the method showed a percentage of false negatives from 22 to 25%. When comparing the two types of scales employed, it can be verified that the 5 levels range, although more subjective, grants more detailed and descriptive results. It presents two categories ("very weak positive" and "strong positive") with assertion of 100%, and, therefore, it is the most suitable scale for future use. The results of Kappa statistics, with values between 0.79 and 0.97, showed inter and intraobserver agreement when applying the luminol test as a presumption test. The PMI diagnosis, based on the records of the hemoglobin reaction with luminol, cannot be used alone. The interpretation of the circumstances of collection and environmental conditions, as well as a critical analysis of the resulting data of the anthropological examination, is required
Buekenhout, Ines. "Quando só restam ossos: estudo da degradação e alteração óssea para estimativa do intervalo post-mortem." Master's thesis, 2014. http://hdl.handle.net/10316/31498.
Full textEstimation of the postmortem interval (PMI) is critical to reconstruct the events surrounding the death of an individual, reason why in recent years forensic anthropologists have played an important role in this area. Despite representing a pertinent question in legal issues, the estimation of PMI is of particular difficulty, not only because of the lack of reliable methods that currently exist to estimate it but also due to the variability of the cadaveric decomposition process. Many studies have demonstrated the variability of the decomposition process, where both extrinsic and intrinsic characteristics to the individual play an important role, as they have also shown that the deposition context and surrounding environment are important to the body’s degradation. Although there has been an increase in the number of studies dealing with these issues, it is clear that there is need for more research, especially ones that focus on skeletonized remains and buried remains. As a result of these difficulties, this thesis has been developed in order to assess the taphonomic changes and their relationship with PMI in 86 skeletonized remains that make up the Collection of Identified Skeletons from the XXIst Century. These remains have been recovered from a burial environment, whereas the changes of the atlas, axis, humerus, femur and first metatarsal were analyzed. In order to verify a possible relationship between PMI and the remains, there were also taken into account extrinsic (such as the date of burial and exhumation and season in which the corpses were buried) and intrinsic (such as gender, age at death and weight of the bones) variables to the individual; determined the stage of decomposition of the remains and analyzed their surface, weight, color, stains, cracks, degradation and exfoliation. However, analysis of the association between the variables in study and PMI did not lead to strong conclusions, with only the number of stains present on the axis showing a slight dependence with the interval. Conversely, the relationship shows a great variability, so if unknown we would not be able to establish with credibility the PMI. Also, the classification of skeletal remains according to stages of degradation showed that the relationship between them and PMI was quite variable for the same time intervals, and therefore does not allow to establish the PMI with credibility. Besides these associations we observed the differential influence of diverse environments on bone degradation; the greater survival of long bones in burial context; increasing degradation of bone with a higher age at death; weight reduction of bone specimens with increasing age at death for each gender; low practicality in establishing the PMI by studying the atlas; unpromising results in the relationship between the PMI of this sample (which is long) and color, stains, cracks and exfoliation of bone surface. We have to bear in mind that, in the present study, the sample is mainly represented by individuals with an advanced age at death and a thirteen to fourteen year old PMI, which may have influenced some of the statistical results. Therefore we cannot trustfully evaluate the relationship between the observed features, PMI and age at death; perhaps a more diverse study sample may have more promising results. Nonetheless, this study also demonstrates how difficult it is to estimate the PMI for the forensic anthropologist since, even for skeletal remains of identical PMI, their classification according to categories of decomposition can be quite variable, making the establishment of a predictive formula complex. Therefore it is important to cross observations with other variables that are known to have influence on the degradation process of the body. Despite the limitations encountered, this thesis allows a better characterization of skeletons that were buried in coffins and may offer new approaches for future studies.
Pina, Rita Sabino Abrantes de. "Utilização de Danio rerio como modelo para a estimativa do intervalo post morten com base no estado de metilação." Master's thesis, 2018. http://hdl.handle.net/10773/25408.
Full textThe post mortem interval (PMI) describes the period of time elapsed from the time of death. A precise estimation of PMI has a strong impact in a crime investigation; however it is a complex task due to the influence of intrinsic and extrinsic factors. There are several methods for PMI determination including pathological, biochemical and entomological. Those methodologies have low precision and several practical limitations leading to emergence of genetic-molecular methods based on the degradation of nucleic acids. DNA methylation is a stable and time-varying epigenetic modification, making it useful for the development of a method to determining PMI. Thus, the methylation levels of a model organism – zebrafish – were analysed during the time since death, in order to create a robust model for the PMI estimation. In this study, we evaluated the variation in global methylation levels and at the promoter region of EDARADD gene during 6 post mortem intervals (0h, 1h, 4h, 24h, 48h e 72h). We performed an optimization of several parameters such us sampling, extraction and amplification of zebrafish genomic DNA. An increase of global methylation levels in the initial post-mortem intervals was observed, followed by an abrupt decrease until 48h post-mortem. Following of the amplification of EDARADD’s promoter region by q-PCR and HRM analysis, it was possible to differentiate the samples according to relative PMI.
Mestrado em Biologia Molecular e Celular
McNealis, Vanessa. "Estimateur bootstrap de la variance d'un estimateur de quantile en contexte de population finie." Thesis, 2019. http://hdl.handle.net/1866/24001.
Full textThis thesis introduces smoothed pseudo-population bootstrap methods for the purposes of variance estimation and the construction of confidence intervals for finite population quantiles. In an i.i.d. context, Hall et al. (1989) have shown that resampling from a smoothed estimate of the distribution function instead of the usual empirical distribution function can improve the convergence rate of the bootstrap variance estimator of a sample quantile. We extend the smoothed bootstrap to the survey sampling framework by implementing it in pseudo-population bootstrap methods. Given a kernel function and a bandwidth, it consists of smoothing the pseudo-population from which bootstrap samples are drawn using the original sampling design. Two designs are discussed, namely simple random sampling and Poisson sampling. The implementation of the proposed algorithms requires the specification of the bandwidth. To do so, we develop a plug-in selection method along with grid search selection methods based on bootstrap estimates of two performance metrics. We present the results of a simulation study which provide empirical evidence that the smoothed approach is more efficient than the standard approach for estimating the variance of a quantile estimator together with mixed results regarding confidence intervals.
Ferreira, Maria Teresa dos Santos. "Para lá da morte : estudo tafonómico de decomposição cadavérica e da degradação óssea e implicações na estimativa do intervalo pós-morte." Doctoral thesis, 2013. http://hdl.handle.net/10316/21839.
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