The shipboard power system supplies energy to sophisticated systems for weapons, communications, navigation, and operation. After a fault is encountered, reconfiguration of a shipboard power system becomes a critical activity that is required to either restore service to a lost load or to meet some operational requirements of the ship. Reconfiguration refers to changing the topology of the power system in order to isolate system damage and/or optimize certain characteristics of the system related to power efficiency. When finding the optimal state, it is important to have a method that finds the desired state within a short amount of time, in order to allow fast response for the system. Since the reconfiguration problem is highly nonlinear over a domain of discrete variables, the genetic algorithm method is a suitable candidate. In this thesis, a reconfiguration methodology, using a genetic algorithm, is presented that will reconfigure a network, satisfying the operational requirements and priorities of loads. Graph theory is utilized to represent the shipboard power system topology in matrices. The reconfiguration process and the genetic algorithm are implemented in MATLAB and tested on an 8-bus power system model and on larger power system with distributed generators by considering different fault scenarios. Each test system was reconfigured in three different ways: by considering load priority, without considering load priority, and by combining priority factor and magnitude factor. The test results accuracy was verified through hand checking.

Electrical power systems are vulnerable to contingencies due to the possibility of fault or damage. When a serious fault (which cannot be removed immediately) occurs in the power system, the fault needs to be isolated, and the remaining system should be reconfigured to make efficient use of available energy. Reconfiguring the system by making an island can be one of the strategies to continue the energy supply using the remaining generation capacity. By analyzing the effect of contingencies on power systems in terms of voltage support, reliability and stability, survivability of the system can be predicted. A survivability index of the system can be developed based on voltage support, reliability and the stability index with predefined weight given to each performance criterion. These weights may vary for different system conditions. The purpose of this research work is to develop a survivability index for shipboard power system and rank reconfiguration choices based on the developed index.

Accuracy of the measurement data used for the decision making process or for shipboard operations and control is very important to ensure the reliability and survivability. The uncertainties present in measurement data need to be minimized for reliable system operation. In this work, a fuzzy logic based model is developed to deal with uncertainty in the meter data. Operational and historical parameters of the meters were used to determine a ‘trust’ value of individual meter. A fuzzy correction system for measurement data was used to generate an input dataset for a genetic algorithm based reconfiguration system. Additionally, with the goal of optimizing the performance of power system operator, the effects of Decision Support System (DSS) on the quality of decisions taken by the operator were examined. Unaided and aided interface prototypes were developed and usability tests were carried out on interface prototypes with users having knowledge of power systems.

This dissertation describes the design, analysis, planning, and control of a self-reconfigurable modular robotic system. The proposed robotic system mainly contains three major types of robotic modules: load carrier, manipulation module, and locomotion module. Each module is capable of navigation and interaction with the environment individually. In addition, the robotic system is proposed to reassemble autonomously into various configurations to perform complex tasks such as humanoid configuration to enable enhanced functionality to reconfigure into a configuration that would enable the system to cross over a ditch. A non-back drivable active docking mechanism with two Degrees of Freedom (DOFs) was designed to fit into the tracked units of the robot modules for achieveing the reconfiguration. The quantity and location of the docking mechanisms are customizable and selectable to satisfy various mission requirements and adapt to different environments. During the reconfiguration process, the target coupling mechanism of each module reconfigurable with each other autonomously. A Lyapunov function-based precision controller was developed to align the target docking mechanisms in a close range and high precision for assembling the robot modules autonomously into other configurations. Additionally, an trajectory optimization algorithm was developed to help the robot determine when to switch the locomotion modes and find the fastest path to the destination with the desired pose. / Doctor of Philosophy / Though the capabilities of individual robot platforms have advanced greatly from their original rigid construction to more modern reconfigurable platforms, it is still difficult to build a singular platform capable of adapting to all situations and environments that users may want or need it to function in. To help improve the versatility of robot systems, modular robots have become an active area of research. These modular robotic systems are made up of multiple robotic platforms capable of docking together, breaking apart, or otherwise reconfiguring to form a multitude of shapes to overcome and adapt to many diverse challenges and environments. This dissertation describes the design of a new modular robotic system with autonomous docking and reconfiguration. Existing technologies and motivations for the creation of a new modular robotic system are covered. Then the physical design, with a primary focus on the docking mechanism, is reviewed. A validation of the proposed robotic system in a virtual environment with real physical properties is demonstrated. Following this, the development of a Lyapunov function-based controller to autonomously align the docking mechanisms is presented. The overall docking process was also preliminarily verified using a prototype of a locomotion module and an active docking mechanism. In addition, the trajectory optimization and tracking methods are presented in the end.

A comparison of two control allocation methods is performed utilizing the F-15 ACTIVE research vehicle. The control allocator currently implemented on the aircraft is replaced in the simulation with a control allocator that accounts for both control effector positions and rates. Validation of the performance of this Moment Rate Allocation scheme through real-time piloted simulations is desired for an aircraft with a high fidelity control law and a larger control effector suite. A more computationally efficient search algorithm that alleviates the timing concerns associated with the early work in Direct Allocation is presented. This new search algorithm, deemed the Bisecting, Edge-Search Algorithm, utilizes concepts derived from pure geometry to efficiently determine the intersection of a line with a convex faceted surface. Control restoring methods, designed to drive control effectors towards a ``desired" configuration with the control power that remains after the satisfaction of the desired moments, are discussed. Minimum-sideforce restoring is presented. In addition, the concept of variable step size restoring algorithms is introduced and shown to yield the best tradeoff between restoring convergence speed and control chatter reduction. Representative maneuvers are flown to evaluate the control allocator's ability to perform during realistic tasks. An investigation is performed into the capability of the control allocators to reconfigure the control effectors in the event of an identified control failure. More specifically, once the control allocator has been forced to reconfigure the controls, an investigation is undertaken into possible performance degradation to determine whether or not the aircraft will still demonstrate acceptable flying qualities. A direct comparison of the performance of each of the two control allocators in a reduced global position limits configuration is investigated. Due to the highly redundant control effector suite of the F-15 ACTIVE, the aircraft, utilizing Moment Rate Allocation, still exhibits satisfactory performance in this configuration. The ability of Moment Rate Allocation to utilize the full moment generating capabilities of a suite of controls is demonstrated. NOTE: (02/2011) An updated copy of this ETD was added after there were patron reports of problems with the file. / Master of Science

FPGAs provide an ideal template for run-time reconfigurable (RTR) designs. Only recently have RTR enabling design tools that bypass the traditional synthesis and bitstream generation process for FPGAs become available. The JBits tool suite is an environment that provides support for RTR designs on Xilinx Virtex and 4K devices. This research provides a comprehensive design process description of a two-dimensional discrete wavelet transform (DWT) core using the JBits run-time reconfigurable FPGA design tool suite. Several aspects of the design process are discussed, including implementation, simulation, debugging, and hardware interfacing to a reconfigurable computing platform. The DWT lends itself to a straightforward implementation in hardware, requiring relatively simple logic for control and address generation circuitry. Through the application of RTR techniques to the DWT, this research attempts to exploit certain advantages that are unobtainable with static implementations. Performance results of the DWT core are presented, including speed of operation, resource consumption, and reconfiguration overhead times. / Master of Science

Les systèmes temps-réel embarqués critiques intègrent un nombre croissant de fonctionnalités comme le montrent les domaines de l'automobile ou de l'aéronautique. Ces systèmes doivent offrir un niveau maximal de sûreté de fonctionnement en disposant des mécanismes pour traiter les défaillances éventuelles et doivent être également performants, avec le respect de contraintes temps-réel strictes. Ces systèmes sont en outre contraints par leur nature embarquée : les ressources sont limitées, tels que par exemple leur espace mémoire et leur capacité de calcul. Dans cette thèse, nous traitons deux problématiques principales de ce type de systèmes. La première porte sur la manière d'apporter une meilleure tolérance aux fautes dans les systèmes temps-réel distribués subissant des défaillances matérielles multiples et permanentes. Ces systèmes sont souvent conçus avec une allocation statique des tâches. Une approche plus flexible effectuant des reconfigurations est utile si elle permet d'optimiser l'allocation à chaque défaillance rencontrée, pour les ressources restantes. Nous proposons une telle approche hors-ligne assurant un dimensionnement adapté pour prendre en compte les ressources nécessaires à l'exécution de ces actions. Ces reconfigurations peuvent demander une réallocation des tâches ou répliques si l'espace mémoire local est limité. Dans un contexte temps-réel strict, nous définissons notamment des mécanismes et des techniques de migration garantissant l'ordonnançabilité globale du système. La deuxième problématique se focalise sur l'optimisation de l'exécution des tâches au niveau local dans un contexte multicoeurs préemptif. Nous proposons une méthode d'ordonnancement optimal disposant d'une meilleure extensibilité que les approches existantes en minimisant les surcoûts : le nombre de changements de contexte préemptions et migrations locales) et la complexité de l'ordonnanceur / Critical real-time embedded systems are integrating an increasing number of functionalities, as shown in automotive domain or aeronautics. These systems require high dependability including mechanisms to handle possible failures and have to be effective, meeting hard real-time constraints. These systems are also constrained by their embedded nature : resources are limited, such as their memory and their computing capacities. In this thesis, we focus on two main problems for this type of systems. The first one is about a way to bring a better fault-tolerance in distributed real-time systems when multiple and permanent hardware failures can occur. In classical systems, the design is limited to a static task assignment. A more flexible approach exploiting reconfigurations is useful if it allows to optimize assignment at each failure for the remaining resources. We propose an off-line approach to obtain an adapted sizing taking into account necessary resources to execute these actions. These reconfigurations may require to reallocate tasks or replicas if memory capacities are limited. In a hard real-time context, we define mechanisms and migration techniques to guarantee global schedulability of the system. The second problem focus on optimizing performance to run tasks at a local level in a multicore preemptive context. We propose an optimal scheduling method allowing a better scalability than existing approaches by minimizing overheads : the number of context switches (local preemptions and migrations) and the scheduler complexity

Nous exposerons dans notre thèse, les éléments déterminants liés à la tradition imagée du Petit chaperon rouge, et aux supports qui lui sont associés, afin de mieux les mettre en perspective avec l'objet de notre étude : voir dans quelle mesure les livres illustrés, albums et autres supports espagnols hébergeant le conte, s’inscrivent à l’intérieur d’une tradition iconographique que nous pourrions qualifier d’européenne,ou en quoi, au contraire, ils rompent avec cette tradition. / We will expose in our thesis, the determining elements related to the pictorial tradition of Little Red Riding Hood, and the media associated with it, to better place them in perspective with the object of our study: to what extent books, illustrated albums and other Spanish media hosting storytelling, enroll in within an iconographic tradition that we might call European, or how, on the contrary, they break with this tradition.

L’objet de cette thèse est d’analyser les caractéristiques et le mode de diffusion du discours RSE , nouveau positionnement éthique des marques. Pour ce faire notre recherche s’est articulée autour d’une enquête ethnosémiotique, déclinée en deux phases : tout d’abord une analyse sémantique de rapports de responsabilité sociale et environnementale (RSE) de trente entreprises à travers la méthode d’analyse cognitivo-discursive puis dans un second temps, des entretiens semi-directifs avec des acteurs professionnels confrontés à ces changements organisationnels. La question principale posée par cette thèse est celle des reconfigurations entrainées par l’intrication sémiotique marque - RSE, nous conduisant par la suite à formuler une théorie de la séméostasie comme décrivant cette faculté d’adaptation sémiotique des organisations face à des facteurs contextuels capables d’altérer leur légitimité. / The purpose of this thesis is to analyze the characteristics and the spreading design of the Corporate and Social Responsibility in Brand strategies. We run this research through a methodology in two steps: first, a semantic analysis of thirty companies’ CSR reports by the Cognitive Discourses analysis and secondly, interviews with professionals facing these organizational changes. The main issue in this work is the semiotic reconfiguration of brands since the emergence of CSR concept. Our conclusions led us to formulate a Semeostasy theory as the description of semiotic adaptability of organizations facing contextual factors that may to affect their legitimacy.

Due to their programmable nature, Field Programmable Gate Arrays (FPGAs) offer a good test environment for reconfigurable systems. FPGAs can be reconfigured during the operation with changing demands. This feature, known as Runtime Reconfiguration (RTR), can be used to speed-up computations and reduce system cost. Moreover, it can be used in a wide range of applications such as adaptable hardware, fault tolerant architectures. This thesis is mostly concentrated on the runtime reconfigurable architectures. Critical properties of runtime reconfigurable architectures are examined. As a case study, a Triple Modular Redundant (TMR) system has been implemented on a runtime reconfigurable FPGA. The runtime reconfigurable structure increases the system reliability against faults. Especially, the weakness of SRAM based FPGAs against Single Event Upsets (SEUs) is eliminated by the designed system. Besides, the system can replace faulty elements with non-faulty elements during the operation. These features of the developed architecture provide extra safety to the system also prolong the life of the FPGA device without interrupting the whole system.