Understanding of carbon cycling in coniferous forests that represent a large carbon sink is crucial for our understanding of natural processes under global climate change. Recognition of fungi as fundamental decomposers can contribute to this understanding. Fungi are able to decompose numbers of substrates and possess a variety of enzymes to do so In this study I present litter decomposing fungi in mountain spruce forest from national park Šumava. The aim of my thesis was to follow succession and community changes of fungi from the early stages of decomposition of Picea abies needles until degradation of organic matter in the organic horizon of the soil. This aim was accomplished partly by recording the extracellular enzyme production of fungi in different stages of decomposition from needles attached to the twigs of a fallen tree to a litter material in later stages of decomposition on the soil surface. In addition to testing of fungi on their natural substrata - needle litter, enzyme activities were also measured in laboratory agar cultures, which allow comparison of diverse fungi with different origins. Enzyme activities were aimed at enzymes decomposing cellulose and compounds found in litter. Although ecology of endophytic and saprothrophic fungi suggest differences in enzyme production, these...

Cette thèse contribue à répondre au problème de la gestion optimale des ressources en eau dans les réseaux de navigation intérieure du point de vue de la théorie du contrôle. Les objectifs principales à atteindre consistent à garantir la navigabilité des réseaux de voies navigables, veiller à la réduction des coûts opérationnels et à la longue durée de vie des équipements. Lors de la conception de lois de contrôle, les caractéristiques des réseaux doivent être prises en compte, à savoir leurs dynamiques complexes, des retards variables et l’absence de pente. Afin de réaliser la gestion optimale, le contrôle efficace des structures hydrauliques doit être assuré. A cette fin, une approche de modélisation orientée contrôle est dérivée. Cependant, la formulation obtenue appartient à la classe des systèmes de descripteurs retardés, pour lesquels la commande prédictive MPC et l’estimation d’état sur horizon glissant MHE peuvent être facilement adaptés à cette formulation, tout en permettant de gérer les contraintes physiques et opérationnelles de manière naturelle. En raison de leur grande dimensionnalité, une mise en œuvre centralisée n’est souvent ni possible ni souhaitable. Compte tenu du fait que les réseaux de navigation intérieure sont des systèmes fortement couplés, une approche distribuée est proposée, incluant un protocole de communication entre agents. Malgré l’optimalité des solutions, toute erreur peut entraîner une gestion inefficace du système. Par conséquent, les dernières contributions de la thèse concernent la conception de stratégies de supervision permettant de détecter et d’isoler les pannes des équipements. Toutes les approches présentées sont appliquées à une étude de cas réaliste basée sur le réseau de voies navigables du nord e la France afin de valider leur efficacité. / This thesis addresses the problem of optimal management of water resources in inland navigation networks from a control theory perspective. The main objectives to be attained consist in guaranteeing the navigability condition of the network, minimizing the operational cost and ensuring a long lifespan of the equipment. However, their complex dynamics, large time delays and negligible bottom slopes complicate their management. In order to achieve the optimal management, the efficient control of the hydraulic structures must be ensured. To this end, a control-oriented modeling approach is derived. The resulting formulation belongs to the class of delayed desciptor systems, for which model predictive control and moving horizon estimation can be easily adapted, as well as being able to deal with physical and operational constraints in a natural manner. However, a centralized implementation is often neither possible nor desirable. As these networks are strongly coupled systems, a distributed approach is followed, featuring a communication protocol among agents. Despite the optimality of the solutions, any malfunction can lead to an inefficient system management. Therefore, the last part of the thesis regards the design of supervisory strategies that allow to detect and isolate faults. All the presented approaches are applied to a realistic case study based on the inland navigation network in the north of France to validate their effectiveness.

This thesis considers the problem of calculating and observing the mixing of modes of positive and negative frequency in inhomogeneous, dispersive media. Scattering of vacuum modes of the electromagnetic field at a moving interface in the refractive index of a dielectric medium is discussed. Kinematics arguments are used to demonstrate that this interface may, in a regime of linear dispersion, act as the analogue of the event horizon of a black hole to modes of the field. Furthermore, a study of the dispersion of the dielectric shows that five distinct configurations of modes of the inhomogeneous medium at the interface exist as a function of frequency. Thus it is shown that the interface is simultaneously a black- and white-hole horizon-like and horizonless emitter. The role, and importance, of negative-frequency modes of the field in mode conversion at the horizon is established and yields a calculation of the spontaneous photonic flux at the interface. An algorithm to calculate the scattering of vacuum modes at the interface is introduced. Spectra of the photonic flux in the moving and laboratory frame, for all modes and all realisable increase in the refractive index at the interface are computed. As a result of the various mode configurations, the spectra are highly structured in intervals with black-hole, white-hole and no horizon. The spectra are dominated by a negative-frequency mode, which is the partner in any Hawking-type emission. An experiment in which an incoming positive-frequency wave is populated with photons is assembled to observe the transfer of energy to outgoing waves of positive and negative frequency at the horizon. The effect of mode conversion at the interface is clearly shown to be a feature of horizon physics. This is a classical version of the quantum experiment that aims at validating the mechanism of Hawking radiation.

Au coeur de l’existence et de l’oeuvre de Bousquet(18971950) se trouve la blessure qu’il reçut à la guerre de 14-18 et qui le condamna à la paralysie. Cette expérience tragique fut la source d’une oeuvre originale et diverse, dans laquelle les correspondances, et plus particulièrement les correspondances amoureuses, tiennent une place importante. Elles sont l’espace dans lequel se déploie une quête d’identité qui passe par la relation à l’altérité, et plus précisément, par la relation amoureuse. L’écriture est vécue par Bousquet comme une tentative de salut, une lutte contre le mal, une quête du sens et de la vérité à travers le langage. Cette écriture intime sonde les profondeurs intérieures de l’homme et s’élève vers la hauteur spirituelle par l’Amour. La recherche de l’unité et de l’essentiel conduit progressivement à l’expression d’une vision du monde qui est aussi une poétique et un enseignement sur la « vraie vie ». / At the core of Joë Bousquet’s life and work (18971950) lies the wound he received during WWI which was to leave him paralysed. Such a tragic experience brought about a unique though diverse achievement, especially through his love letters. Indeed they provide matter for an identity questwhich means how one relates to others, more particularly when love is involved. For Bousquet writing is tantamount to reaching for salvation, it compares with fighting back evil, it is like a quest for meaning and truth by means of words. That deepseated writing probes the inner parts of the human soul, eventually rising up to spiritual heights by means of love. The search for unity and the essential truth also gradually results in a poetical viewing of the world, as well as a lesson of ‘true life’.

In Chapter 2, we propose several two-timescale simulation-based actor-critic algorithms for solution of infinite horizon Markov Decision Processes (MDPs) with finite state-space under the average cost criterion. On the slower timescale, all the algorithms perform a gradient search over corresponding policy spaces using two different Simultaneous Perturbation Stochastic Approximation (SPSA) gradient estimates. On the faster timescale, the differential cost function corresponding to a given stationary policy is updated and averaged for enhanced performance. A proof of convergence to a locally optimal policy is presented. Next, a memory efficient implementation using a feature-vector representation of the state-space and TD (0) learning along the faster timescale is discussed. A three-timescale simulation based algorithm for solution of infinite horizon discounted-cost MDPs via the Value Iteration approach is also proposed. An approximation of the Dynamic Programming operator T is applied to the value function iterates. A sketch of convergence explaining the dynamics of the algorithm using associated ODEs is presented. Numerical experiments on rate based flow control on a bottleneck node using a continuous-time queueing model are presented using the proposed algorithms. Next, in Chapter 3, we develop three simulation-based algorithms for finite-horizon MDPs (FHMDPs). The first algorithm is developed for finite state and compact action spaces while the other two are for finite state and finite action spaces. Convergence analysis is briefly sketched. We then concentrate on methods to mitigate the curse of dimensionality that affects FH-MDPs severely, as there is one probability transition matrix per stage. Two parametrized actor-critic algorithms for FHMDPs with compact action sets are proposed, the ‘critic’ in both algorithms learning the policy gradient. We show w.p1convergence to a set with the necessary condition for constrained optima. Further, a third algorithm for stochastic control of stopping time processes is presented. Numerical experiments with the proposed finite-horizon algorithms are shown for a problem of flow control in communication networks. Towards stochastic optimization, in Chapter 4, we propose five algorithms which are variants of SPSA. The original one measurement SPSA uses an estimate of the gradient of objective function L containing an additional bias term not seen in two-measurement SPSA. We propose a one-measurement algorithm that eliminates this bias, and has asymptotic convergence properties making for easier comparison with the two-measurement SPSA. The algorithm, under certain conditions, outperforms both forms of SPSA with the only overhead being the storage of a single measurement. We also propose a similar algorithm that uses perturbations obtained from normalized Hadamard matrices. The convergence w.p.1 of both algorithms is established. We extend measurement reuse to design three second-order SPSA algorithms, sketch the convergence analysis and present simulation results on an illustrative minimization problem. We then propose several stochastic approximation implementations for related algorithms in flow-control of communication networks, beginning with a discrete-time implementation of Kelly’s primal flow-control algorithm. Convergence with probability1 is shown, even in the presence of communication delays and stochastic effects seen in link congestion indications. Two relevant enhancements are then pursued :a) an implementation of the primal algorithm using second-order information, and b) an implementation where edge-routers rectify misbehaving flows. Also, discrete-time implementations of Kelly’s dual algorithm and primal-dual algorithm are proposed. Simulation results a) verifying the proposed algorithms and, b) comparing stability properties with an algorithm in the literature are presented.

S’intéressant aux différents rôles du son dans les jeux vidéo d’horreur, ce mémoire vise à exposer le travail cognitif effectué par le joueur lors de son activité de jeu. De la structuration des sons jusqu’à la production de sens à partir de leurs fonctions, cette recherche mesure l’implication du phénomène sonore dans la mise en scène de la peur vidéoludique. Dans cette optique, elle présente, critique et développe une pluralité de concepts portant sur la jouabilité, les postures d’écoute, la diégèse, les générateurs sonores, les fonctions sonores systémiques et immersives ainsi que sur la création de la peur à l’aide de différentes stratégies sonores. / Focusing on the different roles of sound in horror videogames, this master thesis aims to expose the cognitive process of a gamer during his gameplay activity. From the structure of the soundscape to the production of meaning through the sound’s functions, this research measures the implication of audio in the creation of a mise en scène of videoludic fear. As a means to do so, it presents, evaluates and develops a plurality of concepts about gameplay, modes of listening, diegesis, sound generators, systemic and immersive audio functions, and the building of fear with different sound strategies.

The traditional landings with large warships near the coastline have been replaced by means of vessels moving beyond the horizon from the coast where the landing will take place. The old landing crafts have been replaced by transport helicopters and close air support, a threat that the amphibious battalion lacks resources to meet. The Swedish Armed Forces faces a possible acquisition of MANPADS and therefore the main purpose with this study was to examine the systems: FIM-92 Stinger RMP, Mistral and RBS70 NG, in order to assess which one of them who had the greatest potential to be effective when used by the amphibious battalion in a coastal defense operation. The study was conducted as a multiple criteria decision analysis, based on the concept of military utility. The result indicated that the RBS70 NG was the system that best met the requirements and demonstrated the greatest potential to be military efficient, although Mistral with minor exceptions fulfilled the requirements. As the study was delimited to a theoretical study based on three specific scenarios, further studies are recommended with simulations, as well as field trials before the result can be given a higher validity. The result, however, already helps us to understand how MANPADS contributes with military utility in coastal defense operations. / De traditionella landstigningarna med stora fartyg uppträdandes kustnära har ersatts med metoder innebärandes att fartygen rör sig bortom horisonten från den kust där landsättningen/landstigningen ska ske. De gamla landstigningsbåtarna har i hög grad ersatts med helikoptrar som understödda av attackhelikoptrar och flygplan utgör den nya dimensionerande hotbilden. En hotbild som amfibiebataljonen saknar resurser för att möta. Då Försvarsmakten står inför en eventuell anskaffning av ett buret luftvärnssystem till amfibiebataljonen har denna undersöknings främsta syfte varit att bedöma vilket av systemen FIM-92 Stinger RMP, Mistral eller RBS70 NG som uppvisat störst potential att vara militärt effektivt när de nyttjas av en amfibiebataljon i kustförsvarsoperationer. Undersökningen genomfördes som en komparativ analys med multimålmetod och tre olika typfall som grund. Jämförelsen tog sin utgångspunkt kring teoribildningen om militär nytta och då mer specifikt militär effektivitet. Resultatet indikerade att RBS70 NG var det system som bäst mötte amfibiebataljonens krav och därmed uppvisade störst potential att vara militärt effektivt, även om Mistral med enstaka undantag också uppfyllde kraven till synes utan begränsningar. Då studien avgränsats till en teoretisk jämförelse i tre specifika typfall, rekommenderas fortsatta studier med såväl simuleringar som praktiska prov innan resultatet kan ges en högre validitet. Resultatet bidrar däremot redan nu till en förståelse för vad som ökar den militära effektivitetenvid genomförande av kustförsvarsoperationer.

Cette thèse traite des phénomènes liés aux mathématiques financières et économiques. Elle est composée de deux sujets de recherche indépendants. La première partie est consacrée à deux contributions au problème de Merton. Pour commencer, nous étudions le problème de l’investissement optimal et de la consommation de Merton dans le cas de marchés discrets dans un horizon infini. Nous supposons qu’il y a des frictions sur les marchés en raison de la perte due aux échanges financières. Ces frictions sont modélisées par des fonctions de pénalités non linéaires où les modèles classiques de coût de transactions étudiés par Magill et Constantinides [31] et les marchés illiquides étudiés par Cetin, Jarrow et Protter dans [6] sont inclus dans cette formulation. Dans ce contexte, la région de solvabilité est définie en tenant compte de cette fonction de pénalité et chaque investisseur doit maximiser son utilité, dérivée de la consommation. Nous donnons la programmation dynamique du modèle et nous prouvons l’existence et l’unicité de la fonction valeur. Des stratégies optimales d’investissement et de consommation sont également construites. Ensuite, nous étendons le modèle de Merton à un problème à plusieurs investisseurs. Notre approche consiste à construire un modèle d’équilibre général déterministe dynamique. Nous prouvons ensuite l’existence d’un équilibre du problème qui est un ensemble de contrôles composés de processus de consommation et de portefeuille, ainsi que les processus de prix qui en découlent afin que la politique de consommation de chaque investisseur maximise son profil. Les résultats obtenus dans cette partie étendent principalement les résultats récemment obtenus par Chebbi et Soner [10] ainsi qu’aux d’autres résultats obtenus dans ce cadre dans la littérature. Dans la deuxième partie, nous traitons le problème de l’existence d’un équilibre d’une économie de production avec des ensembles d’allocations réalisables non-bornés où les consommateurs peuvent avoir des préférences non-transitives non-complètes. Nous introduisons une propriété asymptotique sur les préférences pour les consommations réalisables afin de prouver l’existence d’un équilibre. Nous montrons que cette condition est vraie lorsque l’ensemble des allocations réalisables est compact ou aussi lorsque les préférences sont représentées par des fonctions d’utilité dans le cas où l’ensemble des niveaux d’utilité rationnels individuels réalisables est compact. Cette hypothèse généralise la condition de CPP de Allouch [1] et couvre l’exemple de Page et al. [40] lorsque les niveaux d’utilité disponibles définis ne sont pas compacts. Nous étendons donc les résultats existants dans la littérature avec des ensembles réalisables non bornés de deux façons en ajoutant la production et en prenant en compte des préférences générales. / This PhD dissertation studies two independent research topics dealing with phenomena issues from financial and economic mathematics.This thesis is organized in two parts. The first part is devoted to two contributions tothe Merton problem. First, we investigate the problem of optimal investment and consumption of Merton in the case of discrete markets in an infinite horizon. We suppose that there is frictions in the markets due to loss in trading. These frictions are modeled through nonlinear penalty functions and the classical transaction cost studied by Magill and Constantinides in [31] and illiquidity models studied by Cetin, Jarrow and Protter in [6] are included in this formulation. In this context, the solvency region is defined taking into account this penalty function and every investigator have to maximize his utility, that is derived from consumption, in this region. We give the dynamic programming ofthe model and we prove the existence and uniqueness of the value function. Optimalinvestment and consumption strategies are constructed as well. We second extend the Merton model to a multi-investors problem. Our approach is to construct a dynamic deterministic general equilibrium model. We then provide the existence of equilibrium of the problem which is a set of controls that is composed of consumption and portfolio processes, as well as the resulting price processes so that each investor’s consumption policy maximizes his lifetime expected. The results obtained in this part extends mainly the results recently obtained by Chebbi and Soner [10] and other corresponding results in the litterature.The second part of this thesis deals with the problem of the existence of an equilibrium of a production economy with unbounded attainable allocations sets where the consumers may have non-complete non-transitive preferences. We introduce an asymptotic property on preferences for the attainable consumptions in order to prove the existence of an equilibrium. We show that this condition holds true if the set of attainable allocations is compact or, when preferences are representable by utility functions, if the set of attainable individually rational utility levels is compact. This assumption generalizes the CPP condition of Allouch [1] and covers the example of Page et al. [40] when the attainable utility levels set is not compact. So we extend the previous existence results with unbounded attainable sets in two ways by adding a production sector and considering general preferences.

Micro aerial vehicles and other autonomous systems have the potential to truly transform life as we know it, however much of the potential of autonomous systems remains unrealized because reliable navigation is still an unsolved problem with significant challenges. This dissertation presents solutions to many aspects of autonomous navigation. First, it presents ROSflight, a software and hardware architure that allows for rapid prototyping and experimentation of autonomy algorithms on MAVs with lightweight, efficient flight control. Next, this dissertation presents improvments to the state-of-the-art in optimal control of quadrotors by utilizing the error-state formulation frequently utilized in state estimation. It is shown that performing optimal control directly over the error-state results in a vastly more computationally efficient system than competing methods while also dealing with the non-vector rotation components of the state in a principled way. In addition, real-time robust flight planning is considered with a method to navigate cluttered, potentially unknown scenarios with real-time obstacle avoidance. Robust state estimation is a critical component to reliable operation, and this dissertation focuses on improving the robustness of visual-inertial state estimation in a filtering framework by extending the state-of-the-art to include better modeling and sensor fusion. Further, this dissertation takes concepts from the visual-inertial estimation community and applies it to tightly-coupled GNSS, visual-inertial state estimation. This method is shown to demonstrate significantly more reliable state estimation than visual-inertial or GNSS-inertial state estimation alone in a hardware experiment through a GNSS-GNSS denied transition flying under a building and back out into open sky. Finally, this dissertation explores a novel method to combine measurements from multiple agents into a coherent map. Traditional approaches to this problem attempt to solve for the position of multiple agents at specific times in their trajectories. This dissertation instead attempts to solve this problem in a relative context, resulting in a much more robust approach that is able to handle much greater intial error than traditional approaches.

最近，在考慮一個小型開放經濟體系下，貿易條件(Terms of Trade)外生變化對其經 常帳(Current Account) 影響的相關文獻上，以兩期模型(Infinite-horizon Modcl) 處理時，若貿易條件恆常地惡化，則一方面由於實質所得減少造成儲蓄降低，因而使 得經常帳惡化 (此即所謂「財富效果」) ；另一方面則經由實質利率改變影響儲蓄與 投資決策，因此經常帳再度隨之調整 (此稱為「實質利率效果」) 。至於貿易條件惡 化對於經常帳究有改善或惡化的影響則端視各模型處理時假設不同有不同的結論。 在Heckscher-Ohlin 生產技術的假設下，兩要素用在兩部門間生產，會使得貿易條件 透過第三管道影響經常帳。由Stolper-Samuelson 定理可知，貿易條件惡化將會降低 出口財較密集使用要素的報酬，提高進口財較密集使用要素的報酬，在所得重新分配 之後儲蓄決策將有所改變，因而經常帳也跟著受影響。此稱之為 Stolper-Samuelson 效果。 本文擬運用Blanchard 式的跨代模型(Overlapping-generations Mode)考慮一個小型 開放經濟體系在面臨外生貿易條件惡化時，其經常帳與資本累積的動態變化。此模型 假設每個經濟個體(agent) 活有限期，因此長期均衡值不必滿足時間偏好率等於利率 的條件，我們在此考慮投資與儲蓄的動態決策行為。又由於假設Heckscher-Ohlin 生 產技術，本文也將著重於討論Stolper-Samuelson 效果在此模型中的影響。