Distributed coordination of multi-agent systems (MASs) has been widely studied in various emerging engineering applications, including connected vehicles, wireless networks, smart grids, and cyber-physical systems. In these contexts, agents make the decision locally, relying on the interaction with their immediate neighbors over the connected communication networks. The study of distributed coordination for the multi-agent system (MAS) with constraints is significant yet challenging, especially in terms of ubiquitous uncertainties, the heavy communication burden, and communication delays, to name a few. Hence, it is desirable to develop distributed algorithms for the constrained MAS with these practical issues. In this dissertation, we develop the theoretical results on robust distributed model predictive control (DMPC) algorithms for two types of control problems (i.e., formation stabilization problem and consensus problem) of the constrained and uncertain MAS and apply robust DMPC algorithms in applications of cooperative marine vehicles. More precisely, Chapter 1 provides a systematic literature review, where the state-of-the-art DMPC for formation stabilization and consensus, robust MPC, and MPC for motion control of marine vehicles are introduced. Chapter 2 introduces some notations, necessary definitions, and some preliminaries. In Chapter 3, we study the formation stabilization problem of the nonlinear constrained MAS with un- certainties and bounded time-varying communication delays. We develop a min-max DMPC algorithm with the self-triggered mechanism, which significantly reduces the communication burden while ensuring closed-loop stability and robustness. Chapter 4 investigates the consensus problem of the general linear MAS with input constraints and bounded time-varying delays. We design a robust DMPC-based consensus protocol that integrates a predesigned consensus protocol with online DMPC optimization techniques. Under mild technical assumptions, the estimation errors propagated over prediction due to delay-induced inaccurate neighboring information are proved bounded, based on which a robust DMPC strategy is deliberately designed to achieve robust consensus while satisfying control input constraints. Chapter 5 proposes a Lyapunov-based DMPC approach for the formation tracking control problem of co-operative autonomous underwater vehicles (AUVs) subject to environmental disturbances. A stability constraint leveraging the extended state observer-based auxiliary control law and the associated Lyapunov function is incorporated into the optimization problem to enforce the stability and enhance formation tracking performance. A collision-avoidance cost is designed and employed in the DMPC optimization problem to further guarantee the safety of AUVs. Chapter 6 presents a tube-based DMPC approach for the platoon control problem of a group of heterogeneous autonomous surface vehicles (ASVs) with input constraints and disturbances. In particular, a coupled inter-vehicle safety constraint is added to the DMPC optimization problem; it ensures that neighboring ASVs maintain the safe distance and avoid inter-vehicle collision. Finally, we summarize the main results of this dissertation and discuss some potential directions for future research in Chapter 7. / Graduate / 2023-04-19

Global maternal and newborn mortality have made much progress in recent years. Forexample, newborn deaths have almost halved since the 1990s, and the global maternalmortality rate (MMR) has been reduced by nearly 38 percent during the same period.Maternal and newborn deaths are still unacceptably high, and an estimated 2.7 millionnewborns die worldwide each year, most of them in low-income countries (Lawn et al.,2016). The Mayuge District in rural southeastern Uganda is a district experiencing significantmaternal and newborn health difficulties. According to Willey et al. (2018), 438 expectantmothers die from childbirth-related complications per 100,000 live births, and 23 newbornsdie per 1000 live births in the Mayuge District. The 3-delays model is used in researchconcerning maternal and newborn health worldwide and works to simplify and categorize thecauses of poor maternal and newborn health (Bergström et al., 2009). The delays aredescribed as follows; (1) delay in seeking care; (2) delay in reaching a healthcare facility; and(3) delay in receiving appropriate care.This study focuses on the first delay, which is the delay in seeking healthcare, and examinesif stigma and social identity affect health-seeking behavior in the district. Other identifiedfactors affecting health-seeking behavior will be presented during the study and compiledalongside possible recommended interventions to combat the issues. According to the resultspresented in this study, stigmatization, culture, tradition, and misinformation are evidentdrivers for the delay in seeking healthcare in the Mayuge district in Uganda. This studyfurther reveals that inherited social identity could be identified as traditional aspects andaffect people's health-seeking behavior. It is shown that the district suffers from poormaternal and newborn health caused by all of the three delays presented in this study.However, the results of this study show that the first delay is one of the least researched andthat the local government gives little to no attention to the delay in seeking healthcare in thedistrict.

Les répercussions de la crise économique et politique que le Liban connait aujourd’hui ne se sont pas limitées à ses frontières. Un nombre très important d’individus résidants à l’extérieur de ce pays ont été touchés directement depuis le début de la crise. En effet, depuis octobre 2019, toute personne détenant des dépôts auprès des banques commerciales libanaises se voit refuser l’accès à ces fonds, surtout pour les transferts internationaux. Ces mesures mises en place par les banques commerciales représentent, en l'absence de législation appropriée, un contrôle des capitaux de facto dépourvu de toute légalité aux yeux du droit libanais. Compte tenu de la corruption qui ravage les institutions étatiques et des interférences politiques dans l’appareil judiciaire libanais, un recours depuis le Liban s’avère impossible aujourd’hui pour les déposants étrangers. Ces derniers recherchent désespérément un forum compétent afin d’exercer leurs droits dans l’espoir de récupérer un jour leurs économies investies dans les banques libanaises. De ces déposants, un nombre important réside au Québec. Ce groupe de personnes a subi un préjudice commun susceptible d’engendrer des litiges similaires. Ainsi se pose la question traitée par ce mémoire. En ce qui concerne les déposants québécois, et en considérant les objectifs de l’action collective québécoise, cette procédure pourrait-elle satisfaire leurs besoins d’accès à la justice? Afin de répondre à cette question, plusieurs problématiques se posent. Notamment, la compétence des tribunaux québécois de se saisir de ce litige, la satisfaction de ce dernier aux critères d’autorisation de l’action collective et les difficultés inhérentes à cette procédure dans le contexte factuel particulier. Ainsi, le lecteur comprendra, ce mémoire aura l’aspect d’une étude de cas pratique hypothétique. Toutefois, les enjeux juridiques seront traités en détail et de manière exhaustive. L’objectif principal demeure la faisabilité de ce recours selon le droit positif québécois. / The repercussions of the economic and political crisis that Lebanon is experiencing today are not limited to its borders. A very large number of individuals residing outside this country have been directly affected since the beginning of this crisis. Indeed, since October 2019, any person holding deposits in Lebanese commercial banks has been denied access to these funds, especially in the case of international transfers. These measures put in place by the commercial banks represent a de facto capital control that is, absent appropriate legislation, illegal under Lebanese law. Given the corruption that plagues state institutions and the political interference in the Lebanese judiciary, recourse from Lebanon is impossible today for foreign depositors. These account holders are desperately seeking a competent forum to exercise their rights in the hope of one day recovering their savings invested in Lebanese banks. Of these depositors, a large number resides in Quebec. This group of people have suffered a common prejudice that could lead to similar litigation. This raises the question addressed by this thesis. With respect to Quebec plaintiffs and considering the objectives of the Quebec class action, could this procedure satisfy their need for access to justice? In order to answer this question, several elements must be considered. In particular, the jurisdiction of the Quebec courts to hear this case, whether it meets the criteria for certification of a class action and the difficulties inherent to this procedure considering the peculiar factual context. Thus, the reader will understand that this thesis will have the aspect of a hypothetical practical case study. However, the legal issues will be dealt with in detail and in a comprehensive manner. The main objective remains to determine the feasibility of this recourse within the framework of Quebec's positive law.

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Weather-related delays in the aviation sector will always occur, however, through effective delay management and improved weather forecasting, the impact and duration of delays can be reduced. The research examined the type of weather that caused departure delays, due to adverse weather at the departure station, namely O. R. Tambo International Airport (ORTIA), over the period 2010 to 2013. It was found that the most significant weather that causes such delays are thunderstorms, followed by fog. Other noteworthy elements are rainfall, without the influence of other weather elements, and icing. It was also found that the accuracy of a weather forecast does not impact on the number of departure delays, and thus departure delays due to weather at the departure station are largely unavoidable. However, the length and impact of such delays can be reduced through improved planning. The study highlights that all weather-related delays can be reduced by improved weather forecasts, effective assessment of the weather forecast, and collaborative and timely decision making. A weather impact index system was designed for ORTIA and recommendations for delay reductions are made. / Geography / M. Sc. (Geography)

This study addresses the specific barriers related to time delays in the treatment of patients who suffered acute myocardial infarction at the Al Ain Hospital accident and emergency unit in the United Arab Emirates. A comprehensive background of the UAE is given for the benefit of students who have limited access to the background and challenges facing medical and nursing personnel in providing thrombolythic therapy to patients who suffered from acute myocardial infarction. The study will contribute to the continuous quality management and improvement of overall nursing and medical care of the AMI patient who is eligible for thrombolysis. An extensive literature review addresses the clinical manifestations and treatment of the patient suffering from AMI as well as the adverse effects of time delays in treatment during the acute phase of the disease. The researcher selected a quantitative, non-experimental descriptive and retrospective study. Data was collected by a structured instrument to gather the desired responses from the files of 457 selected patients admitted to the Al Ain Hospital. This study emphasizes the need to improve patient care by all health care personnel in an accident and emergency unit to prevent the delays in treatment in life threatening conditions such as myocardial infarction ensuring optimal and prompt time to thrombolyse. The improvement of awareness and commitment by health care providers such as nurses, doctors and ambulance personnel, can be achieved through education and training, commitment and dedication, absolute cooperation, collaboration and constant update on performance. Regular audits are essential with regard to door-to-needle time and performance of all health care providers. This study ultimately show that time constrains in attending to patients presenting with myocardial infarction should be addressed in utmost urgency. / Health Studies / M. A. (Health Studies)

Cette thèse est centralisée sur cette question : comment est-ce que le système visuel peut coder efficacement la position des objets en mouvement, en dépit des diverses sources d'incertitude ? Cette étude déploie une hypothèse sur la connaissance a priori de la cohérence temporelle du mouvement (Burgi et al 2000; Yuille and Grzywacz 1989). Nous avons ici étendu le cadre de modélisation précédemment proposé pour expliquer le problème de l'ouverture (Perrinet and Masson, 2012). C'est un cadre d'estimation de mouvement Bayésien mis en oeuvre par un filtrage particulaire, que l'on appelle la prévision basé sur le mouvement (MBP). Sur cette base, nous avons introduit une théorie du codage de position basée sur le mouvement, et étudié comment les mécanismes neuronaux codant la position instantanée de l'objet en mouvement pourraient être affectés par le signal de mouvement le long d'une trajectoire. Les résultats de cette thèse suggèrent que le codage de la position basé sur le mouvement peut constituer un calcul neuronal générique parmi toutes les étapes du système visuel. Cela peut en partie compenser les effets cumulatifs des délais neuronaux dans le codage de la position. En outre, il peut expliquer des changements de position basés sur le mouvement, comme par example, l'Effect de Saut de Flash. Comme un cas particulier, nous avons introduit le modèle de MBP diagonal et avons reproduit la réponse anticipée de populations de neurones dans l'aire cortical V1. Nos résultats indiquent qu'un codage en position efficace et robuste peut être fortement dépendant de l'intégration le long de la trajectoire. / Coding the position of moving objects is an essential ability of the visual system in fulfilling precise and robust tracking tasks. This thesis is focalized upon this question: How does the visual system efficiently encode the position of moving objects, despite various sources of uncertainty? This study deploys the hypothesis that the visual systems uses prior knowledge on the temporal coherency of motion (Burgi et al 2000; Yuille and Grzywacz 1989). We implemented this prior by extending the modeling framework previously proposed to explain the aperture problem (Perrinet and Masson, 2012), so-called motion-based prediction (MBP). This model is a Bayesian motion estimation framework implemented by particle filtering. Based on that, we have introduced a theory on motion-based position coding, to investigate how neural mechanisms encoding the instantaneous position of moving objects might be affected by motion. Results of this thesis suggest that motion-based position coding might be a generic neural computation among all stages of the visual system. This mechanism might partially compensate the accumulative and restrictive effects of neural delays in position coding. Also it may account for motion-based position shifts as the flash lag effect. As a specific case, results of diagonal MBP model reproduced the anticipatory response of neural populations in the primary visual cortex of macaque monkey. Our results imply that an efficient and robust position coding might be highly dependent on trajectory integration and that it constitutes a key neural signature to study the more general problem of predictive coding in sensory areas.

Design trade-offs between estimation performance, processing delay and communication cost for a sensor scheduling problem is discussed. We consider a heterogeneous sensor network with two types of sensors: the first type has low-quality measurements, small processing delay and a light communication cost, while the second type is of high quality, but imposes a large processing delay and a high communication cost. Such a heterogeneous sensor network is common in applications, where for instance in a localization system the poor sensor can be an ultrasound sensor while the more powerful sensor can be a camera. Using a time-periodic Kalman filter, we show how one can find an optimal schedule of the sensor communication. One can significantly improve estimation quality by only using the expensive sensor rarely. We also demonstrate how simple sensor switching rules based on the Riccati equation drives the filter into a stable time-periodic Kalman filter. ￜ 2008 IEEE. / <p>QC 20110224</p>

The aim of this thesis is to investigate the dynamical behaviors of spatially extended systems with fluctuating time delays. In recent years, the study of spatially extended systems and systems with fluctuating delays has experienced a fast growth. In ubiquitous natural and laboratory situations, understanding the action of time-delayed signals is a crucial for understanding the dynamical behavior of these systems. Frequently, the length of the delay is found to change with time. Spatially extended systems are widely studied in many fields, such as chemistry, ecology, and biology. Self-organization, turbulence, and related nonlinear dynamic phenomena in spatially extended systems have developed into one of the most exciting topics in modern science. The first part of this thesis considers the discrete system. Diffusively coupled map lattices with a fluctuating delay are used in the study. The uncoupled local dynamics of the considered system are represented by the delayed logistic map. In particular, the influences of diffusive coupling and fluctuating delay are studied. To observe and understand the influences, the results for the considered system are compared with coupled map lattices without delay and with a constant delay as well as with the uncoupled logistic map with fluctuating delays. Identifying different patterns, determining the existence of traveling wave solutions, and specifying the fully synchronized stable state are the focus of this part of the study. The Lyapunov exponent, the master stability function, spectrum analysis, and the structure factor are used to characterize the different states and the transitions between them. The second part examines the continuous system. The delay is introduced into the reactionterm of the Fisher-KPP equation. The focus of this part of study is the time-delay-induced Turing instability in one-component reaction-diffusion systems. Turing instability has previously only been found in multiple-component reaction-diffusion systems. However, this work demonstrates with the help of the stability exponent that fluctuating delay can result in Turing instability in one-component reaction-diffusion systems as well. / Ziel der vorliegenden Arbeit ist die Untersuchung der Einflüsse der zeitlich fluktuierenden Verzögerungen in räumlich ausgedehnten diffusiven Systemen. Durch den Vergleich von Systemen mit konstanter Verzögerung bzw. Systemen ohne räumliche Kopplung erhält man ein tieferes Verständnis und eine bessere Beschreibungsweise der Dynamik des räumlich ausgedehnten diffusiven Systems mit fluktuierenden Verzögerungen. Im ersten Teil werden diskrete Systeme in Form von diffusiven Coupled Map Lattices untersucht. Als die lokale iterierte Abbildung des betrachteten Systems wird die logistische Abbildung mit Verzögerung gewählt. In diesem Teil liegt der Fokus auf Musterbildung, Existenz von Multiattraktoren und laufenden Wellen sowie der Möglichkeit der vollen Synchronisation. Masterstabilitätsfunktion, Lyapunov Exponent und Spektrumsanalyse werden benutzt, um das dynamische Verhalten zu verstehen. Im zweiten Teil betrachten wir kontinuierliche Systeme. Hier wird die Fisher-KPP Gleichung mit Verzögerungen im Reaktionsteil untersucht. In diesem Teil liegt der Fokus auf der Existenz der Turing Instabilität. Mit Hilfe von analytischen und numerischen Berechnungen wird gezeigt, dass bei fluktuierenden Verzögerungen eine Turing Instabilität auch in 1-Komponenten-Reaktions-Diffusionsgleichungen gefunden werden kann