As modern technology continues to affect civilization, the issue of electronic rights grows in a global conversation. The right to be forgotten is a data protection regulation specific to the European Union but its consequences are creating an international stir in the fields of mass communication and law. Freedom of expression and privacy rights are both founding values of the United States which are protected by constitutional amendments written before the internet also changed those fields. In a study that analyzes the legal process of when these two fundamental values collide, this research offers insight into both personal and judicial views of informational priority. This thesis conducts a legal analysis of cases that cite the infamous precedents of Melvin v. Reid and Sidis v. F-R Pub. Corp., to examine the factors on which U.S. courts of law determinewhether freedom or privacy rules.

Les Contrôleurs du VIH sont de rares individus capables de contrôler spontanément la réplication virale en l’absence de traitement. De nombreuses études montrent que les Contrôleurs développent des réponses T antivirales remarquablement efficaces. Les cellules T CD4+ spécifiques de Gag pourraient jouer un rôle particulier car cette population est préservée en comparaison aux patients traités et corrèle négativement avec la charge virale. Afin d’étudier cette population, nous avons réalisé une analyse transcriptionnelle et protéique multiplexée sur cellule unique, à partir de cellules T CD4+ détectées ex vivo par marquage tétramère de CMH-II contre le peptide Gag293 (Tet+). Nous avons comparé l’expression de 44 gènes et 6 protéines membranaires chez 9 patients Contrôleurs et 9 patients traités. Nous avons d’une part validé la forte fréquence de cellules T CD4+ Tet+ chez les Contrôleurs en comparaison aux patients traités et, d’autre part, montré que les cellules T CD4+ Tet+ des Contrôleurs, étaient activées et engagées dans une différenciation Th1 avancée et présentant un profil cytotoxique. De plus, les cellules T CD4+ Tet+ de Contrôleurs ont montré un état d’épuisement limité, reflété par une expression faible de PD-1, qui pourrait être l’une des raisons du maintien de leur fréquence et de leurs fonctions. Dans une deuxième étude, nous avons étudié les cellules T folliculaires « helper » (Tfh) dans la population T CD4+ spécifique de Gag chez les Contrôleurs du VIH. Les Tfh jouent un rôle essentiel dans la maturation d’affinité des anticorps en aidant les cellules B. Afin de déterminer si ce sous-type cellulaire joue un rôle dans le contrôle de l’infection à VIH, nous avons analysé le phénotype et la fonction des Tfh circulantes (cTfh) : cellules T CD4+ CD45RA- CXCR5+). Nous avons utilisé un marquage tétramère de CMH-II contre le peptide Gag293, pour détecter les cTfh spécifiques du VIH (cTfh Tet+), et nous avons montré que cette population est préférentiellement maintenue chez les Contrôleurs du VIH. L’analyse phénotypique de la population cTfh Tet+ a montré une intensité d’expression (MFI) de PD-1 plus importante dans le groupe de patients traités, suggérant une activation immune anormale chez ces patients. La fonction des cTfh, analysée pour leur capacité à induire la sécrétion d’IgG en coculture avec des cellules B mémoires autologues, n’a pas montré de différences majeures entre les groupes en terme de production d’IgG totales. Cependant, la production d’IgG spécifiques anti-VIH est significativement plus efficace chez les Contrôleurs, en particulier pour la réponse anti-Env qui est plus de 30 fois supérieure à celle des patients traités. Enfin, la fréquence des cTfh Tet+ a corrélé positivement avec la production d’IgG spécifiques, supportant l'idée d'un rôle important de la fonction Tfh dans la réponse humorale anti-VIH. L’ensemble de ces résultats indique que la population T CD4+ spécifique de Gag supporte chez les Contrôleurs les deux bras de la réponse immunitaire antivirale : d’une part, une réponse de type cellulaire Th1 montrant un profil cytotoxique et, d’autre part, une réponse de type humorale, reflétée par des interactions cTfh/B préservées, résultant en une réponse B mémoire vigoureuse. Le maintien de la fonction et de la fréquence de ces cellules spécifiques de Gag pourrait donc jouer un rôle important dans le contrôle du VIH / HIV Controllers are rare individuals able to spontaneously control viral replication in the absence of treatment. Several studies showed that controllers develop effective anti-viral T cell responses. Gag-specific CD4+ T cells could play a particular role in HIV control, because this population is preserved in comparison with the treated patients and correlates negatively with the viral load. In order to study this population, we performed a multiplexed single cell transcriptional and protein analysis from CD4+ T cells detected ex vivo by MHC-II tetramer labeling against the Gag293 peptide (Tet+). We compared the expression of 44 genes and 6 surface proteins in 9 Controllers patients and 9 treated patients. Firstly, we validated the high frequency of Tet+ CD4+ T cells in controllers compared to the treated patients, then we showed that Tet+ CD4+ T cells from controllers were activated and engaged in advanced Th1 differentiation with a cytotoxic profile. In addition, Tet+ CD4+ T cells from controllers showed a limited state of exhaustion, reflected by a lower expression of PD-1, which could be one of the reasons for maintaining their frequency and functions. In a second study, we studied follicular helper T cells (Tfh) among the Gag-specific CD4+ T cell population of HIV controllers. Tfh plays an essential role in the affinity maturation of the antibody response by providing help to B cells. To determine whether this CD4+ T cell subset may contribute to the spontaneous control of HIV infection, we analyzed the phenotype and function of circulating Tfh (cTfh: T cells CD4+ CD45RA- CXCR5+). We performed a MHC-II tetramer labeling against Gag293 peptide to detect HIV-specific cTfh (cTfh Tet +), and showed that this population is preferentially maintained in HIV controllers. Phenotypic analysis of Tet+ cTfh population showed a higher intensity of PD-1 expression (MFI) in the treated group suggesting abnormal immune activation in these patients. The function of cTfh, analyzed by the capacity to promote IgG secretion in cocultures with autologous memory B cells, did not show major differences between groups in terms of total IgG production. However, the production of HIV-specific IgG is significantly more efficient in the controller group, especially for the anti-Env response that is more than 30-fold greater than those of the treated patients. Finally, the frequency of Tet+ cTfh correlated positively with the production of specific IgG, supporting the idea of an important role of Tfh function in the humoral antiHIV response. Taken together, these results indicate that Gag-specific CD4+ T cell population supports the two arms of the antiviral immune response in HIV controllers: the cell-mediated response through a preferential differentiation toward Th1 cell type showing a cytotoxic profile, and the humoral response, reflected by preserved cTfh / B interactions, resulting in a vigorous memory response. Maintaining the function and frequency of these Gag-specific CD4+ T cells could therefore play an important role in HIV control

This thesis presents the design of various controllers for a highly maneuverable, high performance aircraft, namely the modified F-18. The aircraft was required to perform high angle-of-attack maneuvers, for which the aircraft behaves in as a highly nonlinear system. An adaptive PID controller was used to control the aircraft through these high angle-of-attack maneuvers. Several nonlinear controllers were then developed based on the adaptive PID control, and were tested for robustness. This thesis also looks at an improvement in the aircraft which may improve performance in high angle-of-attack maneuvers. The contributions of this thesis are in the areas of control, in general, and specifically in the area of aircraft control. Successful application of linear adaptive control and nonlinear control were presented. In the area of aircraft control, controllers were presented which produce good performance for high angle-of-attack maneuvers, while maintaining implementability. Also, some insight is gained into what aircraft changes could improve performance. / Graduation date: 1995

University of Macau / Faculty of Science and Technology / Department of Electrical and Electronics Engineering

This dissertation develops a general framework for designing stabilizing feedback controllers and observers for dynamics with state/time dependent gains on the control signals and measured outputs. These gains have potential singularity periods but satisfy a technically non-trivial condition referred to as persistence of excitation. A persistence filter design constitutes the primary theoretical innovation of this work around which the controller and observer development is centered. Application areas of singular gain systems considered in this study include robotics, biomechanics, intelligent structures and spacecrafts. Several representative problems involving singular, time-dependent gains are addressed. The specific contributions of this dissertation are outlined as follows: (i) a stabilizing feedback for linear, single-input systems with time-varying, singular control scaling is designed that allows arbitrary exponential convergence rate for the closed-loop dynamics. An adaptive control generalization of this result allows asymptotic convergence in presence of unknown plant parameters. An extension to a special, single-input nonlinear system in the controller canonical form is also proposed. It is proven that this control design results in bounded tracking error signals for a trajectory tracking objective; (ii) observer design for linear, single-output systems with time-varying, singular measurement gains is considered. A persistence filter similar in structure to the control counterpart aids an observer design that guarantees exponential state reconstruction with arbitrary convergence rates; (iii) the observer and controller designs are combined to obtain an exponentially stabilizing output feedback controller for linear, single-input, single-output dynamics with singular gains on both the control and measurements. A novel separation property is established as a consequence. The construction motivates applications to stabilization with reversible transducers which can switch between sensor and actuator modes. The results are verified on two illustrative applications, vibration control using piezoelectric devices and inverted pendulum stabilization with a DC motor. The linear result is further generalized to include state dependent gains; (iv) application of the persistence filter theory to spacecraft attitude stabilization using intermittent actuation is explored. The intermittence is characterized by a time-varying, periodically singular control gain. A nonlinear persistence filter allows construction of an exponentially stabilizing controller and simulations verify convergence with intermittent actuation where conventional proportional-derivative control fails; (v) a stabilization result for a special multi-input, linear system with time-varying matrix control gains is presented. The matrix gain is assumed to be diagonal but allows fewer controls than states subject to a controllability assumption in absence of the singular gain matrix. The single-input adaptive control results are shown to extend to the multi-input case. An application to angular velocity stabilization of an underactuated rigid spacecraft is considered. / text

Η παρούσα διπλωματική ασχολείταιμε τις σύγχρονες μεθόδους που εφαρμόζονται στα συστήματα ηλεκτρικής ενέργειας για την βελτίωση των χαρακτηριστικών τους χρησιμοποιώντας αφενός τις τεχνολογικές εξελίξεις στον τομέα των ημιαγωγικών διακοπτικών στοιχείων και αφετέρου την εγκατεστημένη θεωρία ελέγχου. Στο κεφάλαιο 1 επιχειρείται μια εισαγωγή στις έννοιες των συστημάτων μεταφοράς ηλεκτρικής ενέργειας (ΣΗΕ) καθώς και στην αρχή λειτουργίας τους.Στη συνέχεια γίνεται αναφορά στην έννοια της ποιότητας ισχύος και στα προβλήματα που παρουσιάζονται στα ηλεκτρικά δίκτυα. Τέλος αναφέρονται τα προβλήματα εκείνα που με την πάροδο του χρόνου έκαναν επιτακτική την εισχώρηση της τεχνολογίας των ηλεκτρονικών ισχύος στο πεδίο τους και ιδιαίτερα στην κατεύθυνση της αντιστάθμισης αέργου ισχύοςπου αποτελεί ένα απο τα κυριότερα προβλήματα. Στο κεφάλαιο 2 συνεχίζουμε αναλύοντας τη μορφή που παίρνουν τα σύγχρονα ΣΗΕ μετά την είσοδο της τεχνολογίας των FACTS ξεκινώντας από τα θυρίστορ ,ηλεκτρονικούς διακόπτες ισχύος,που αποτελούν δομικά στοιχεία των νέων διατάξεων και επόμενα τις γενικότερες διατάξεις που χρησιμοποιούνται στα ΣΗΕ που συνδυάζουν τα νέα στοιχεία ακόμα και με τους μηχανικούς διακόπτες που ήταν ο προηγούμενος τρόπος ελέγχου των ΣΗΕ. Στο κεφάλαιο 3 γίνεται μια πιο ενδελεχή αναφορά στα κυκλώματα τεχνολογίας ηλεκτρονικών ισχύος που χρησιμοποιύνται ώστε να πάρουν μορφή οι προηγούμενες διατάξεις ,ξεκινώντας από τη βασική μονάδα του μετατροπέα ημιγέφυρας δομικό στοιχείο των DC/AC μετατροπέων.Ακόμα στο κεφάλαιο αυτό αναφερόμαστε στον έλεγχοτων διατάξεων ,αναλύοντας τα συστήματα αναφοράς και τις τεχνικές που υπάρχουν για να καταστεί δυνατή η οδήγησή τους. Στο κεφάλαιο 4 τα πράγματα γίνονται πιο συγκεκριμένα και αναφερόμαστε στο στατικό αντισταθμιστή (STATCOM).Παρουσιάζονται τα κυκλώματα ελέγχου που περιέχει έτσι ώστε να γίνεται δυνατός ο έλεγχος τάσης είτε διάφορες άλλες δυνατότητες που μπορεί να προσφέρει στο πλαίσιο της καλύτερης λειτουργίας των σύγχρονων ΣΗΕ.Επίσης αναπτύσσεται το μαθηματικό και δυναμικό μοντέλο με τις εξισώσεις στα βήματα του οποίου θα κινηθεί και η προσομοίωση του επόμενου κεφαλαίου. Στο κεφάλαιο 5 γίνεται προσομοίωση της λειτουργίας του στατικού αντισταθμιστή και παρουσιάζονται διάφορα διαγράμματα από τα επιμέρους κυκλώματα που αναδεικνύουν τη λειτουργία του.Κύριο αντικείμενο και εδώ αποτελεί η θεωρία ελέγχου και ιδιαίτερη μνεία γίνεται στην χρησιμοποίηση των PI ελεγκτών εκείνω οι οποίοι ρυθμίζουν παραμέτρους του συστήματος και μετουσιώνουν τη μετάβαση από τα παλαιότερα συστήματα που χρησιμοποιούνταν στα ΣΗΕ όπως ο έλεγχος με μηχανικούς διακόπτες. Στο κεφάλαιο 6 τέλος προχωράμε σε κάποιες ιδέες και προτάσεις για μελλοντική έρευνα ως αποτέλεσμα της ενασχόλησης με την συγκεκριμένη διπλωματική εργασία. / In capter 1 there is an intoduction to the Electrical Power Systems terminology,as well as their function and principles.Next,the meaining of power quality is presented along with the problems that occur at the electrical main grids.More emphsis is given to the ones that gradually enforced the use power electronics for reactive power compensation. In chapter 2,an analysis is made about the form of the modern Electrical Power Systems after the development of the FACT technology,starting from thyristors ,electronic power switches,which are elementsof the new layout and continuing with other modern devices which combine these new elements even with the old mechanical switches. In chapter 3,the electronic power systems' circuits are examined more thorouglyin order to understand the layout of the aforementioned structures,starting from the elementary unit of the half bridge power converter.Moreover,the control of these structures is examined,analyzing the reference systems and the various techniques in order to drive them. Chapter 4, presents the static compensator (STATCOM) along with its control circuits.In addition, the mathematical and dynamic model is developed, forming equations where the simulation of the next chapter is based. In chapter 5,there is a simulation of STATCOM's function (in MATLAB software) and various diagrams are presented showing different variables during its operation.Main purpose of this section is the presentation of the control theory,highlighting the use of PI controllers which adjust the system's parameteres and realize the transition from the older structures used in Electrical Power Systems ,such us mechanical switching. In chapter 6,we present some ideas in terms of future survey as a result of our dealing with the certain thesis

This master thesis deals with the virtual gate position and liquid level control system. The main characteristics of automatic control systems, fuzzy logic systems, their properties and formation principles are reviewed. Conventional and advanced control methods are presented pointing out their benefits, drawbacks and problems to be solved. Physical modelling and simulation issues are also discussed. Physical, mathematical, simulation and animation models of the system are produced. Position and level controllers are designed. The simulation of gate position and liquid level control processes is performed. The simulation model is built up using MATLAB Simulink and Fuzzy Logic Toolbox. The simulation results prove that the proportional controller fits very well for controlling gate position. However, the results of liquid level control “upwards” using PI controller are only satisfactory. Unsatisfactory results are obtained using the same controller for liquid level control “downwards”. Substantially better results are achieved using fuzzy logic controller. The models produced can be useful for further investigations and learning purposes.

The focus of this research is on deriving small signal stability models for different Flexible AC Transmission Systems devices by introducing a simple systematic method that is applicable to any dynamic device. Two different small signal models for Unified Power Flow Controllers are introduced. One model is called the power control mode and the other model is the voltage control mode. The two models are compared from transient stability point of view to show the necessity of developing both models for UPFC. The thesis also shows how to derive the small signal stability model of Static Synchronous Compensator, as the shunt branch of UPFC. The small signal stability models of both devices are then validated to ensure the accuracy of the derived models. STATCOM and UPFC power control mode are validated against PSCAD. The UPFC voltage control mode is validated against nonlinear solution of system equations.

The focus of this research is on deriving small signal stability models for different Flexible AC Transmission Systems devices by introducing a simple systematic method that is applicable to any dynamic device. Two different small signal models for Unified Power Flow Controllers are introduced. One model is called the power control mode and the other model is the voltage control mode. The two models are compared from transient stability point of view to show the necessity of developing both models for UPFC. The thesis also shows how to derive the small signal stability model of Static Synchronous Compensator, as the shunt branch of UPFC. The small signal stability models of both devices are then validated to ensure the accuracy of the derived models. STATCOM and UPFC power control mode are validated against PSCAD. The UPFC voltage control mode is validated against nonlinear solution of system equations.

Thesis (M.S.) -- Mississippi State University. Department of Electrical and Computer Engineering. / Title from title screen. Includes bibliographical references.