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controllers for discrete-time systems and time-delayed systems. By using bilinear transformation and orthogonal transformation, earlier research results obtained in the continuous-time case are extended to discrete-time situation. The complete set of stabilizing PID controllers for the discrete-time systems is thus obtained. Moreover, this set remains to be a union of convex sets when one particular parameter is fixed. Thus a method to design robust and non-fragile digital PID controllers is proposed by following a similar design procedure for the continuous-time systems. In order to find the stabilizing controller set for systems with time-delays, the relationship between the Nyquist Criterion and Pontryagin’s theory is investigated. The conditions under which one can correctly apply the Nyquist Criterion to time-delayed systems are derived. Then, the complete set of stabilizing PID controllers for arbitrary order LTI systems with time-delay up to a given value is obtained. Furthermore, the stability issue of a system with fixed-delay is also studied and a formula which provides complete knowledge of the distribution of the closed-loop poles is presented. Based on this formula, stabilizing P and PI controller sets for the system with fixed-delay can be computed.

La détermination des caractéristiques vibratoires est une étape cruciale lors du processus de certification d'une structure ou lors de l'évaluation de sa détérioration. Quelle que soit la technique utilisée, l'identification des modes d'une structure nécessite d'effectuer des essais de vibration. Durant ces essais, on effectue des mesures qui permettent d'observer la réponse du système à une excitation connue, partiellement connue ou inconnue. Les méthodes d'identification modale sont des méthodes globales. Elles permettent de déterminer les modes de la structure à partir d'un post-traitement des données mesurées. Certaines techniques d'identification modale, telles que les méthodes basées sur la minimisation d'erreur de modélisation ARX ou les méthodes sous-espaces, se sont fortement répandues dans le monde industriel ces quinze dernières années. Cependant, malgré ce succès, ces méthodes ne fourniront jamais les paramètres modaux exacts de la structure étudiée. En effet, à cause de nombreuses sources d'erreurs (e.g. bruits sur les capteurs, bruits environnementaux), l'identification modale à partir de données réelles ne peut mener qu'à des estimations des paramètres modaux. Une estimation est par définition entachée d'une erreur statistique, la variance. Le but de cette thèse est l'étude approfondie de l'estimation de cette erreur statistique. Le manuscrit est découpé en trois partie. La première concerne la description détaillée de deux familles d'identification modale (minimisation d'erreur de modélisation ARX et méthodes sous-espace). La seconde partie décrit le principe de l'estimation des incertitudes et fournit les chaînes de propagation des variances. La troisième partie présente une validation poussée de ces méthodes dans le but d'une utilisation opérationnelle. / Determinination of vibration characteristics is a crucial step for structure certification or health monitoring. Whatever the method, modes identification of a structure requires vibration tests. During these tests, measurements are made in order to observe responses of the system to known, partially known or unknown excitations. Modal identification methods are global methods. They allow the determination of modes from data post-treatment. Some modal identification methods, such as those based on ARX modelisation error minimisation or subspace methods, have been largely spread into the industry for about fifteen years. Despite this succes, these methods will never provide exact results. Indeed, due to numerous error sources (e.g. sensor noises, environmental noises), modal identifications based on measured data can only lead to modal parameters estimations. By definition, an estimation is subject to statistical errors, also called variances. The purpose of this thesis is to give an in-depth study of these statistical errors estimation. This document is divided in three parts. Firstly, a description of two kind of modal identification methods (ARX modelisation error minimisation and subspace methods) is given. Secondly, the uncertainty estimation principle is explained and propagation schemes of variances are given. Finally, the third part provides an in-depth validation of these methods in order to proceed to industrial utilisations.

Nous avons montré que, dans l'intestin, les cellules exprimant le marqueur spécifique des lymphocytes Natural Killer (NK), NKp46 peuvent être divisées en deux compartiments, par rapport au facteur de transcription RORyt. Les cellules NKp46+RORyt- sont des cellules NK intestinales immatures. Cependant, les cellules NKp46+RORyt- s'apparentent aux cellules "lymphoid tissue-inducer" (LTi), puisqu'elles requièrent RORyt pour leur développement et produisent de l'IL-22, cytokine essentielle pour l'homéostasie et la réponse antimicrobienne épithéliale. Notre recherche actuelle vise à établir les relations ontogéniques et la signature génétique de ces cellules au niveau pan-génomique. La fonction in vivo des cellules NKp46+ intestinales est adressée dans un modèle unique d'infection par voie orale avec Listeria monocytogenes. L'ensemble de nos résultats a montré que les cellules NKp46+ ont une place légitime dans la famille émergente des cellules intestinales de l'immunité innée. / Natural Killer (NK) cells are NKp46+CD3- innate lymphocytes, which exhibit cytotoxicityand cytokine production, mainly IFN-γ, as major effector functions. In mammals, theexpression of natural cytotoxic receptor NKp46 is essentially restricted to NK cellcompartment. However, we showed that in mouse intestine, NKp46 marker defines aheterogeneous cell population, differentially expressing the retinoic acid orphan receptorRORγt. NKp46+RORγt- cells harbor reduced cytotoxicity and IFN-γ production, consistentwith an immature NK cell phenotype. In contrast, NKp46+RORγt+ cells resemble lymphoidtissue inducer cells (LTi) in their developmental requirement for RORγt and their ability toproduce IL-22. This cytokine is critical for epithelial homeostasis and antimicrobial responseat several epithelial sites.By using a genome wide profiling approach, we confirmed that gut NKp46+RORγt- cellsare the only gut NKp46+ cell population related to conventional splenic NK cells, while gutNKp46+RORγt+ cells are linked to LTi cells. Transcriptional signatures specific of distinct gutNKp46+ cell subsets are currently under intensive investigation in order to determine novelfunctional properties.We assessed gut NKp46+ cell subsets in vivo function during oral infection with entericpathogen Listeria monocytogenes (L.m.). Although immune responses to systemic L.minfection have been widely characterized in mice, L.m. cannot breach mouse intestinal barrier,thus limiting the knowledge of early immune responses at the natural site of infection. Using aunique transgenic mouse lineage restoring L.m. intestinal invasiveness, we showed that gutNKp46+RORγt- and NKp46+RORγ t+ cells respond to L.m. infection by producing IFN-γ andIL-22, respectively. Further investigation of the cellular mechanisms leading to gut NKp46+cell subset activation, as well as the contribution of these cells to the control of bacterialdissemination is in progress.Altogether our data provide novel insight into intestinal innate immunity and highlight gutNKp46+ cell subsets as “legitimate” members of the emerging family of intestinal innatelymphoid cells

A backbone network is the central part of the communication network, which provides connectivity within the various systems across large distances. Disruptions in a backbone network would cause severe consequences which could manifest in the service outage on a large scale. Depending on the size and the importance of the network, its failure could leave a substantial impact on the area it is associated with. The failures of the network services could lead to a significant disturbance of human activities. Therefore, making backbone communication networks more resilient directly affects the resilience of the area. Contemporary urban and regional development overwhelmingly converges with the communication infrastructure expansion and their obvious mutual interconnections become more reciprocal. Spreading failures are of particular interest. They usually originate in a single network segment and then spread to the rest of network often causing a global collapse. Two types of spreading failures are given focus, namely: epidemics and cascading failures. How to make backbone networks more resilient against spreading failures? How to tune the topology or additionally protect nodes or links in order to mitigate an effect of the potential failure? Those are the main questions addressed in this thesis. First, the epidemic phenomena are discussed. The subjects of epidemic modeling and identification of the most influential spreaders are addressed using a proposed Linear Time-Invariant (LTI) system approach. Throughout the years, LTI system theory has been used mostly to describe electrical circuits and networks. LTI is suitable to characterize the behavior of the system consisting of numerous interconnected components. The results presented in this thesis show that the same mathematical toolbox could be used for the complex network analysis. Then, cascading failures are discussed. Like any system which can be modeled using an interdependence graph with limited capacity of either nodes or edges, backbone networks are prone to cascades. Numerical simulations are used to model such failures. The resilience of European National Research and Education Networks (NREN) is assessed, weak points and critical areas of the network are identified and the suggestions for its modification are proposed.

A backbone network is the central part of the communication network, which provides connectivity within the various systems across large distances. Disruptions in a backbone network would cause severe consequences which could manifest in the service outage on a large scale. Depending on the size and the importance of the network, its failure could leave a substantial impact on the area it is associated with. The failures of the network services could lead to a significant disturbance of human activities. Therefore, making backbone communication networks more resilient directly affects the resilience of the area. Contemporary urban and regional development overwhelmingly converges with the communication infrastructure expansion and their obvious mutual interconnections become more reciprocal. Spreading failures are of particular interest. They usually originate in a single network segment and then spread to the rest of network often causing a global collapse. Two types of spreading failures are given focus, namely: epidemics and cascading failures. How to make backbone networks more resilient against spreading failures? How to tune the topology or additionally protect nodes or links in order to mitigate an effect of the potential failure? Those are the main questions addressed in this thesis. First, the epidemic phenomena are discussed. The subjects of epidemic modeling and identification of the most influential spreaders are addressed using a proposed Linear Time-Invariant (LTI) system approach. Throughout the years, LTI system theory has been used mostly to describe electrical circuits and networks. LTI is suitable to characterize the behavior of the system consisting of numerous interconnected components. The results presented in this thesis show that the same mathematical toolbox could be used for the complex network analysis. Then, cascading failures are discussed. Like any system which can be modeled using an interdependence graph with limited capacity of either nodes or edges, backbone networks are prone to cascades. Numerical simulations are used to model such failures. The resilience of European National Research and Education Networks (NREN) is assessed, weak points and critical areas of the network are identified and the suggestions for its modification are proposed.

A Laringotraqueíte Infecciosa (LTI) é uma doença respiratória altamente contagiosa, que acomete principalmente galinhas, é causada por um Gallid herpesvirus tipo 1. As aves infectam-se através do trato respiratório e por via ocular, sendo as aves com infecção clínica as principais transmissoras do vírus. Outras fontes de transmissão são as aves com infecções latentes, materiais de cama e fômites contaminados. Os sinais clínicos geralmente aparecem entre 6 a 12 dias da exposição natural e em infecções experimentais entre 4 a 7 dias pós infecção (p.i). Na forma subclínica pode-se observar uma leve traqueíte mucoide, sinusite, conjuntivite, com morbidade variável e baixa mortalidade. Na forma severa, as aves apresentam depressão, dispneia, espirros, corrimento nasal, conjuntivite, expectoração de secreção sanguinolenta. A taxa de morbidade é alta, comprometendo 100% do lote e a mortalidade pode ocorrer em até 70% do plantel, embora taxas de 10 a 20% sejam as mais frequentes. O agente causador desta doença pode ser propagado na membrana corio-alantóide (MCA) de embriões de frango em desenvolvimento e replicado em células de rim de frangos adultos, como também, em uma variedade de células epiteliais de embrião como do rim, do fígado e do pulmão. Existem vários procedimentos para o diagnóstico da LTI como: a observação de sinais clínicos, a observação de lesões macroscópicas e lesões histopatológicas e o uso de técnicas moleculares como: RFLP, PCR e PCR em tempo real. Como a PCR em tempo real apresenta uma maior sensibilidade quando comparada com outros métodos de diagnóstico, permite quantificar o número de cópias amplificadas do genoma viral, assim como, a diferenciação da doença na fase aguda ou crônica, reduzindo o número de possíveis falsos positivos, esta foi usada para a detecção deste vírus. O objetivo deste trabalho foi isolar o VLTI em ovos embrionados, descrever as lesões macroscópicas causadas pelo vírus, detectar o vírus pela reação de PCR em tempo real, usando como alvo da reação o gene ICP4, padronizar uma reação de PCR em Tempo Real usando a glicoproteína E como alvo da reação e propor o seu uso no diagnóstico de rotina. / The Infectious Laryngotracheitis (ILT) is a highly contagious respiratory disease that affects mainly chickens; caused by a Gallid herpesvirus type 1. Infect birds, by the respiratory tract and by the ocular route, the birds with clinical infection the main transmission of the virus. Other transmission sources are birds with latent infections, bedding materials and contaminated fomites. Clinical signs generally appear between 6 to 12 days exposure of the natural and in experimental infections between 4 and 7 days post infection (p.i). In subclinical form can observe a slight mucoid tracheitis, sinusitis, conjunctivitis, variable morbidity and low mortality. In the severe form, the birds present depression, dyspnea, sneezing, nasal discharge, conjunctivitis, expectoration of bloody discharge. The morbidity rate is high, impairing the lot 100% and mortality may occur in up to 70% of the flock, although 10 to 20% rates are the most frequent. The causative agent of this disease can be propagated in chorioallantoic membrane (CAM) of chicken embryos develop and replicated in adult chicken kidney cells as well as in a variety of epithelial-cell embryo as kidney, liver and lung. There are several procedures for the diagnosis of LTI as observation of clinical signs, observation of gross lesions and histopathological lesions, and the use of molecular techniques as RFLP, PCR and real time PCR. As the real-time PCR has greater sensitivity compared to other diagnostic methods to quantify the number of amplified copies of the viral genome, as well as the differentiation of the disease in the acute or chronic phase, reducing the number of potential false positives, this was used for detection of virus. The objective of this study was to isolate the VLTI in embryonated eggs, describe macroscopic lesions caused by the virus, detect the virus by PCR reaction in real time, using as a target of reaction the ICP4 gene, standardize a PCR reaction in real time using the glycoprotein E as a target of reaction and propose their use in routine diagnosis.

A Laringotraqueíte Infecciosa (LTI) é uma doença respiratória altamente contagiosa, que acomete principalmente galinhas, é causada por um Gallid herpesvirus tipo 1. As aves infectam-se através do trato respiratório e por via ocular, sendo as aves com infecção clínica as principais transmissoras do vírus. Outras fontes de transmissão são as aves com infecções latentes, materiais de cama e fômites contaminados. Os sinais clínicos geralmente aparecem entre 6 a 12 dias da exposição natural e em infecções experimentais entre 4 a 7 dias pós infecção (p.i). Na forma subclínica pode-se observar uma leve traqueíte mucoide, sinusite, conjuntivite, com morbidade variável e baixa mortalidade. Na forma severa, as aves apresentam depressão, dispneia, espirros, corrimento nasal, conjuntivite, expectoração de secreção sanguinolenta. A taxa de morbidade é alta, comprometendo 100% do lote e a mortalidade pode ocorrer em até 70% do plantel, embora taxas de 10 a 20% sejam as mais frequentes. O agente causador desta doença pode ser propagado na membrana corio-alantóide (MCA) de embriões de frango em desenvolvimento e replicado em células de rim de frangos adultos, como também, em uma variedade de células epiteliais de embrião como do rim, do fígado e do pulmão. Existem vários procedimentos para o diagnóstico da LTI como: a observação de sinais clínicos, a observação de lesões macroscópicas e lesões histopatológicas e o uso de técnicas moleculares como: RFLP, PCR e PCR em tempo real. Como a PCR em tempo real apresenta uma maior sensibilidade quando comparada com outros métodos de diagnóstico, permite quantificar o número de cópias amplificadas do genoma viral, assim como, a diferenciação da doença na fase aguda ou crônica, reduzindo o número de possíveis falsos positivos, esta foi usada para a detecção deste vírus. O objetivo deste trabalho foi isolar o VLTI em ovos embrionados, descrever as lesões macroscópicas causadas pelo vírus, detectar o vírus pela reação de PCR em tempo real, usando como alvo da reação o gene ICP4, padronizar uma reação de PCR em Tempo Real usando a glicoproteína E como alvo da reação e propor o seu uso no diagnóstico de rotina. / The Infectious Laryngotracheitis (ILT) is a highly contagious respiratory disease that affects mainly chickens; caused by a Gallid herpesvirus type 1. Infect birds, by the respiratory tract and by the ocular route, the birds with clinical infection the main transmission of the virus. Other transmission sources are birds with latent infections, bedding materials and contaminated fomites. Clinical signs generally appear between 6 to 12 days exposure of the natural and in experimental infections between 4 and 7 days post infection (p.i). In subclinical form can observe a slight mucoid tracheitis, sinusitis, conjunctivitis, variable morbidity and low mortality. In the severe form, the birds present depression, dyspnea, sneezing, nasal discharge, conjunctivitis, expectoration of bloody discharge. The morbidity rate is high, impairing the lot 100% and mortality may occur in up to 70% of the flock, although 10 to 20% rates are the most frequent. The causative agent of this disease can be propagated in chorioallantoic membrane (CAM) of chicken embryos develop and replicated in adult chicken kidney cells as well as in a variety of epithelial-cell embryo as kidney, liver and lung. There are several procedures for the diagnosis of LTI as observation of clinical signs, observation of gross lesions and histopathological lesions, and the use of molecular techniques as RFLP, PCR and real time PCR. As the real-time PCR has greater sensitivity compared to other diagnostic methods to quantify the number of amplified copies of the viral genome, as well as the differentiation of the disease in the acute or chronic phase, reducing the number of potential false positives, this was used for detection of virus. The objective of this study was to isolate the VLTI in embryonated eggs, describe macroscopic lesions caused by the virus, detect the virus by PCR reaction in real time, using as a target of reaction the ICP4 gene, standardize a PCR reaction in real time using the glycoprotein E as a target of reaction and propose their use in routine diagnosis.

The extensive use of a least-squares problem formulation in many fields is partly motivated by the existence of an analytic solution formula which makes the theory comprehensible and readily applicable, but also easily embedded in computer-aided design or analysis tools. While the mathematics behind convex optimization has been studied for about a century, several recent researches have stimulated a new interest in the topic. Convex optimization, being a special class of mathematical optimization problems, can be considered as generalization of both least-squares and linear programming. As in the case of a linear programming problem there is in general no simple analytical formula that can be used to find the solution of a convex optimization problem. There exists however efficient methods or software implementations for solving a large class of convex problems. The challenge and the state of the art in using convex optimization comes from the difficulty in recognizing and formulating the problem. The main goal of this thesis is to investigate the potential advantages and benefits of convex optimization techniques in the field of system identification. The primary work focuses on parametric discrete-time system identification models in which we assume or choose a specific model structure and try to estimate the model parameters for best fit using experimental input-output (IO) data. By developing a working knowledge of convex optimization and treating the system identification problem as a convex optimization problem will allow us to reduce the uncertainties in the parameter estimation. This is achieved by reecting prior knowledge about the system in terms of constraint functions in the least-squares formulation.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-11-06T21:15:29Z No. of bitstreams: 1 SauloRufinoDeSa_DISSERT.pdf: 3478146 bytes, checksum: 9f2991a36a301f1a974d7af46a7c48a8 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-11-20T23:52:10Z (GMT) No. of bitstreams: 1 SauloRufinoDeSa_DISSERT.pdf: 3478146 bytes, checksum: 9f2991a36a301f1a974d7af46a7c48a8 (MD5) / Made available in DSpace on 2017-11-20T23:52:10Z (GMT). No. of bitstreams: 1 SauloRufinoDeSa_DISSERT.pdf: 3478146 bytes, checksum: 9f2991a36a301f1a974d7af46a7c48a8 (MD5) Previous issue date: 2017-08-17 / Os Objetos de Aprendizagem (OAs) s?o recursos modulares reutiliz?veis importantes para a Educa??o a Dist?ncia (EaD) e integram os Ambientes Virtuais de Aprendizagem (AVAs), compondo o leque de op??es que podem ser utilizadas pelos professores em seu projeto de ensino. Os OAs podem ficar diretamente hospedados em um AVA ou armazenados em um Reposit?rio de Objetos de Aprendizagem (ROA), que s?o pr?prios para hosped?-los de forma centralizada, descrevendo suas caracter?sticas e utilizando metadados padronizados com mecanismo de busca eficiente para encontrar o objeto solicitado. Para que os objetos sejam acessados e utilizados em mais de um AVA, ? necess?rio a exist?ncia de mecanismos que os tornem interoper?veis. Este artigo trata da proposta de uma arquitetura e interface para integra??o dos objetos de um reposit?rio com o AVA Moodle utilizando a especifica??o LTI. / The Learning Objects (LO) are importants modular and reusable resources to Distance Education thatt composes the Learning Management Systems (LMS), building a tool kit that can be used for teachers in their learning project and a course?s activity fluxs.The LOs can ber hosted directly into LMS or stored into Learning Objects Repositories (LOR), that are suitable to host them in centered form, describing their details using metadata and with eficient search engine for find the requested object. The stored objects in the LOR can be accessed and used in severals LMSs that include them, increasing the resource available variety to mount a course whith their evaluative activities. This dissertation aproachs the proposal of architecture for integration of the Distance Education Secretary?s (DES) LOR of Federal University of Rio Grande do Norte with LMS Moodle using tha LTI especification developed by IMS Global Leaning Consortion.