Dissertations / Theses on the topic 'Intelligence reconfigurable'

Thesis (M.S. in Electrical Engineering)--Naval Postgraduate School, December 2006.
Thesis Advisor(s): Douglas J. Fouts. "December 2006." Includes bibliographical references (p. 105-106). Also available in print.

Dynamic reconfiguration of logic circuits has been a research problem for over four decades. While applications using logic reconfiguration in practical scenarios have been demonstrated, the design of these systems has proved to be a difficult process demanding the skills of an experienced reconfigurable logic design expert. This thesis proposes an automatic synthesis method which relieves designers of some of the difficulties associated with designing partially dynamically reconfigurable systems. A new design abstraction model for reconfigurable systems is proposed in order to support design exploration using the presented method. Given an input behavioural model, a technology server and a set of design constraints, the method will generate a reconfigurable design solution in the form of a 3D floorplan and a configuration schedule. The approach makes use of genetic algorithms. It facilitates global optimisation to accommodate multiple design objectives common in reconfigurable system design, while making realistic estimates of configuration overheads and of the potential for resource sharing between configurations. A set of custom evolutionary operators has been developed to cope with a multiple-objective search space. Furthermore, the application of a simulation technique verifying the lll results of such an automatic exploration is outlined in the thesis. The qualities of the proposed method are evaluated using a set of benchmark designs taking data from a real reconfigurable logic technology. Finally, some extensions to the proposed method and possible research directions are discussed.

Thesis (M.S. in Electrical Engineering)--Naval Postgraduate School, March 2008.
Thesis Advisor(s): Fouts, Douglas J. ; Pace, Phillip E. "March 2008." Description based on title screen as viewed on May 16, 2008. Includes bibliographical references (p. 101-102). Also available in print.

Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2011.
ENGLISH ABSTRACT: Swarm intelligence research was inspired by biological systems in nature. Working ants and bees has captivated researchers for centuries, with the ant playing a major role in shaping the future of robotic swarm applications. The ants foraging activity can be adapted for different applications of robotic swarm intelligence. Numerous researchers have conducted theoretical analysis and experiments on the ants foraging activities and communication styles. Combining this information with modern reconfigurable computing opens the door to more complex behaviour with improved system dynamics. Reconfigurable computing has numerous applications in swarm intelligence such as true hardware parallel processing, dynamic power save algorithms and dynamic peripheral changes to the CPU core. In this research a brief study is made of swarm intelligence and its applications. The ants' foraging activities were studied in greater detail with the emphasis on a layered control system designed implementation in a robotic agent. The robotic agent’s hardware was designed using a partial self reconfigurable FPGA as the main building element. The hardware was designed with the emphasis on system flexibility for swarm application drawing attention to power reduction and battery life. All of this was packaged into a differential drive chassis designed specifically for this project.
AFRIKAANSE OPSOMMING: Die motivering vir swerm robotika kom van die natuur. Vir eeue fassineer swerm insekte soos bye en miere navorsers. Dit is verstommend hoe ’n groep klein en nietige insekte sulke groot take kan verrig. Die mier speel ‘n belangrike rol en is die sentrale tema van menige publikasies. Die mier se kos-soek aktiwiteit kan aangepas word vir swerm robotika toepassings. Hierdie aktiwiteit vervat verskeie sleutel konsepte wat belangrik is vir robotika toepassings. Deur bv. die mier se aktiwiteite te kombineer met dinamies herkonfigureerbare hardeware, kan meer komplekse gedrag bestudeer word. Die stelsel dinamika verbeter ook, aangesien dit nou moontlik is om sekere take in parallel uit te voer. Deur ’n interne prosesseerder in die herkonfigureerbare hardeware in te sluit, is dit nou vir die stelsel moontlik om homself te verander tydens taak verrigting. Komplekse krag bestuur gedrag is ook moontlik deurdat die prosesseerder die spoed en rand apparaat kan verander soos benodig. ‘n Verdere voordeel is dat die stelsel aanpasbaar is en dus vir verskeie navorsingsprojekte gebruik kan word. In hierdie navorsing word ’n literatuur studie van swerm robotika gemaak en word daar ook na toepassings gekyk. Met die klem op praktiese implementering, word die mier se kos-soek aktiwiteit in detail ondersoek deur gebruik te maak van ’n laag beheerstelsel. In hierdie laag beheerstelsel verteenwoordig elke laag ’n hoër vlak gedrag. Stelsel aanpasbaarheid en lae kragverbruik speel ’n deurslaggewende rol in die ontwerp, en om hierdie rede vorm ’n FPGA die hart van die sisteem.

As Máquinas de Vetores de Suporte (SVMs) têm sido largamente empregadas em diversas aplicações, graças à sua baixa taxa de erros na fase de testes (boa capacidade de generalização) e o fato de não dependerem das condições iniciais. Dos algoritmos desenvolvidos para o treinamento da SVM, o Sequential Minimal Optimization (SMO) é um dos mais rápidos e eficientes para a execução desta tarefa. Importantes implementações da fase de treinamento da SVM têm sido feitas em FPGAs. A maioria destas implementações tem sérias restrições na quantidade de conjunto de amostras a serem treinadas, pelo fato de implementarem soluções numéricas. De observação na literatura técnica, apenas dois trabalhos implementaram o SMO para o treinamento SVM em hardware e apenas um destes possibilita o treinamento de uma quantidade importante de amostras, porém a aplicação é restrita a apenas um benchmark específico. Na última década, com a tecnologia baseada em RAM estática, os FPGAs apresentaram um novo aspecto de flexibilidade: a capacidade de reconfiguração dinâmica, que possibilita a alteração do sistema em tempo de execução trazendo redução de área. Adicionalmente, apesar de uma potencial penalidade no tempo de processamento, a velocidade de execução continua muito superior quando comparada com soluções em software. No presente trabalho, uma solução genérica é proposta para o treinamento SVM em hardware (i.e. uma arquitetura que possibilite o treinamento para diversos tipos de amostras de entrada), e, motivado pela natureza seqüencial do algoritmo SMO, uma arquitetura dinamicamente reconfigurável é desenvolvida. Um estudo da implementação genérica com codificação em ponto fixo é apresentada, assim como os efeitos de quantização. A arquitetura é implementada no dispositivo Xilinx Virtex-IV XC4VLX25. Dados de tempo e área são obtidos e detalhes da síntese são explorados. É feita uma simulação da reconfiguração dinâmica através de chaves de isolação para a validação do sistema sob reconfiguração dinâmica. A arquitetura foi testada para três diferentes benchmarks, com resultados indicando que o treinamento no hardware reconfigurável foi acelerado em até 30 vezes quando comparado com a solução em software e os estudos apontaram que uma economia de até 22,38% de área útil do FPGA pode ser obtida dependendo das metodologias de síntese e implementação adotadas.
Support Vector Machines have been largely used in different applications, due to their high classifying capability without errors (generalization capability) and the advantage of not depending on the initial conditions. Among the developed algorithms for the SVM training, the Sequential Minimal Optimization (SMO) is one of the fastest and the one of the most efficient algorithms for executing this task. Important dedicated hardware implementations of the training phase of the SVM have been proposed for digital FPGA. Most of them are very restricted about the quantity of input samples to be trained due to the fact that they implement numeric solutions. Only two works with implementation in the SMO algorithm for the SVM training in hardware have been reported recently, and just one is able to train an important quantity of input samples, however it is restricted for only one specific benchmark. In the last decade, with the technology based on static memory (SRAM), FPGAs has provided a unique aspect of flexibility: the capability of dynamic reconfiguration, which involves altering the programmed design at run-time and allows area\'s saving. In addition, although leading to some time penalty, the execution time is still faster when compared with purely software solutions. In this work we present a totally hardware general-purpose implementation of the SMO algorithm. In this general-purpose approach, training of examples with different number of samples and elements are possible, and, motivated by the sequential nature of some of the SMO tasks, a dynamically reconfigurable architecture is developed. A study of the general-purpose implementation with fixed-point codification is presented, as well as the quantization effects. The architecture is implemented in the Xilinx Virtex-IV XC4VLX25 device, and timing and area data are provided. Synthesis details are exploited. A simulation using dynamic circuit switching is carried out in order to validate the systems dynamic reconfiguration aspects. The architecture was tested in the training of three different benchmarks; the training on the reconfigurable hardware was accelerated up to 30 times when compared with software solution, and studies points to an area saving up to 22.38% depending on the synthesis and implementation methodologies adopted in the project.

Le Contrôle intelligente d'un système autonome dans un environnement dynamique et dangereux exige la capacité d'identifier les menaces d'échec et de planifier les réponses temps-réel qui peut assurer la sécurité et l'objectif du système autonome. Nous proposons une architecture pour le contrôle intelligent en temps-réel, appelée ORICA. Elle se compose d'un sous-système de raisonnement IA et d'un sous-système d'exécution temps-réel de réponse. Le sous-système de raisonnement modélise des caractéristiques temporelles et logiques du comportement environnemental et planifie les réponses du système. Le sous-système temps-réel, composé d'une partie logicielle et d'une partie matérielle, exécute ces réponses pour éviter l'échec du système autonome. Il donne une performance inégalée par rapport aux précédentes approches conventionnelles. Le comportement unique de l'intelligence reconfigurable est implanté dans la partie matérielle, avec un circuit logique reprogrammable (FPGA)
Autonomous intelligent control system for a dynamic and dangerous environment necessitates the capacity to identify the failure threats and to plan the real-time responses that ensure safety and goal achievement by the autonomous system. We propose a real-time intelligent control architecture called ORICA. It consists of an AI reasoning subsystem and a real-time response execution subsystem. The AI reasoning subsystem models the temporal and logical characteristics of the environment and plans the system responses. The real-time subsystem, which is composed of a software section and a hardware section, executes these responses to avoid failure of the autonomous system. Its performance behavior is unparalleled by the previous classical approaches (pure hardware or pure software). The software section uses behavior switching according to the frequency of external events and a unique reconfigurable intelligence behavior has been implemented in hardware section, using a reprogrammable chip (FPGA)

De nos jours, les communications sans fil sont devenues un moyen incontournable et universel d'échange d'un large éventail d'informations entre différents systèmes, certains d'entre eux étant en mouvement comme des drones parmi tant d'autres. Dans le contexte de cette thèse nous considérons une liaison entre un projectile et une station de base. La géométrie de la structure ainsi que les contraintes aérodynamiques d'un tir balistique impliquent l'utilisation d'antennes patchs dans la partie conique à l'avant du projectile. Ce type d'antenne est facile à intégrer à une plate-forme en tant que réseau conformé tout en respectant les contraintes d'encombrement. Ces communications doivent être fiables et discrètes dans un environnement perturbé ou hostile. Les diagrammes de rayonnement du réseau d'antennes doivent présenter des caractéristiques spécifiques, notamment dans le cas particulier d'objets volants et possédant une rotation en roulis (rotation autour de son axe) qui impliquent l'utilisation d'un réseau phasé et commuté par rapport à sa position. Une antenne qui présenterait un rayonnement fixe assurerait une liaison avec un interlocuteur, mais rayonnerait également dans d'autres directions sensibles ce qui pourraient interférer avec la communication principale. La solution qui consiste à activer et désactiver des sous-réseaux verticaux afin d'orienter le lobe principal dans la plan orthogonal à la pointe semble être en accord avec les contraintes de la structure tournante. Un réseau conique a été étudié puis 2 prototypes ont été fabriqués, dont un à l'ISL. Les sous-réseaux sont répartis de manière égale autour de la pointe de façon à pouvoir rayonner dans toutes les directions. De plus, chaque sous-réseau est composé de trois éléments ce qui permet d'orienter également le lobe principal dans le plan longitudinal de la pointe (le long de l'axe du projectile) grâce à un dépointage électronique. Un système électronique de formation de faisceaux a été développé dans le but de contrôler 12 éléments rayonnants. Le réseau d'antennes ainsi que le circuit de répartition ont été caractérisés dans un premier temps de manière indépendante afin d'optimiser les lois de phase nécessaires à dépointer le lobe à partir des pondérations mesurées. Au final, le réseau de 12 éléments associé à son système d'alimentation dédié a été mesuré dans les chambres anéchoïques de DGA-MI et de l'ISL et les mesures sont en accord avec les simulations
Nowadays wireless communications have become a useful and universal mean to exchange a wide range of information between different systems, some of them being moving, as UAVs among others. In this context we consider here the link between a projectile and a base station. The shape of the structure and the aerodynamic constraints involve the use of patch antennas in the conical front part. This class of antenna is easy to be integrated into the platform as a conformal array, while respecting space constraint. Communications have to be reliable and discrete in disturbed or hostile environment. Antennas array radiation patterns must have some specific characteristics, in particular in the case of flying objects with spin which involves the use of a switched phased array considering its roll position. A fixed-radiation pattern antenna may presents a relevant level or gain toward the interlocutor, but also toward sensitive directions, in which may be located others systems, interfering with the current communication. The solution to switch on and off vertical sub-arrays to steer the beam in the azimuthal plane seem convenient ant fitting the requirements of rotating platform. A conical phased array was studied and two prototypes were manufactured, one at ISL. Sub-arrays are distributed around the conical shape in order to be able to radiate in each direction. Moreover, each sub-array are composed of three radiating elements allowing to steer the main antenna beam in many direction (along the projectile fuze axes). A beam forming network was developed to control the 12 radiating elements conical array. The antenna array and the feeding network were characterized independently in order to optimized the phase of each radiating element. Finally, measurements were done on the whole system in the DGA-MI and ISL anechoic chambers and are in good agreement with simulation results

Sixth Generation (6G) of wireless networks will be even more heterogeneous and dense as compared to Fifth Generation (5G) and other legacy networks. Thus, the 6G architecture will need to be adapted to serve the ever-evolving capacity and quality of service requirements. To satisfy these ever-increasing demands, multiple enablers such as visible light communication, light fidelity, Reconfigurable Intelligent Surfaces (RISs), THz communications, etc., have been proposed. Specifically, RISs, through their programmable characteristics, can perform the fine-grained manipulation of the radio signals being generated by the myriad transmitter devices/access points for their corresponding receivers. Such manipulations include absorption of certain components of the impinging radio signals, as well as fine-grained control of these signals in terms of direction, polarization, phase, and power in a frequency-selective manner. An RIS consists of a device that controls the behavior of the Electromagnetic (EM) waves, alongside circuits that provide the tuning mechanism and the intelligence to control it. This device that controls the EM wave behavior can be realized using Metasurfaces (MSs), which are electromagnetically thin-film and planar artificial structures that enable the control of EM fields in engineered and even atypical ways. Hence, the MS is a component of the RIS. On a more granular level, an MS is composed of subwavelength building blocks known as unit cells or meta-atoms. The design of these unit cells depends on the required EM functionality, reconfigurability, or accuracy. The promises of the RIS paradigm, therefore, come at the expense of a non-trivial complexity in the MS. On the one hand, the performance of an RIS depends on the size of the unit cells, the number of unit cell states, or the size of the whole MS. On the other hand, there are costs and energy overheads associated with the fabrication and operation of RISs that also scale with the aforementioned factors. This thesis aims to bridge this gap by providing a method to dimension the RIS through a design-oriented scalability analysis of programmable MSs. Besides the challenge of design complexity, MSs will become prone to failure as they continue integrating sophisticated tuning, control and sensing circuits. However, the impact of faults on the performance of individual MSs is not well understood yet. This thesis proposes a framework to evaluate the impact of failures in programmable MSs, distinguishing between the type of faults and their spatial distribution. While RIS generally hinge on the design of rather complex tunable MSs, such a complexity can be amortized if the functionality provided by the RIS can be shared among multiple users. This thesis introduces a coding (i.e. digital programming of unit cells) technique based on the momentum conservation law and superposition of waves for MS reconfiguration to engineer multiple beams independently. Then, the wireless channel of such framework among multiple users is evaluated. The capacity is increased at least one order of magnitude compared to a scenario without RIS. Machine learning techniques, and particularly Neural Networks (NNs), owing to their ability to learn complex relationships between input and output data, are capable of solving differential equations, thereby circumventing the need for numerical calculations. This thesis provisions a data-driven NN-based approach for determining an accurate estimation of the radiation pattern or several measures of interest that enable the full characterization of the radiation pattern. In summary, contributions of this thesis fall under the umbrella of paving the way to realizing 5G and beyond wireless communications empowered with RIS technology.
La sisena generació (6G) de xarxes sense fils seran encara més denses i heterogènies que les xarxes de cinquena generació. Per tant, la arquitectura de les xarxes 6G necessitaran adaptar-se a necessitats de capacitat i qualitat de servei en constant canvi. Per servir aquestes necessitats creixents, s’han proposat diverses tecnologies com comunicacions a l’espectre visible, Light Fidelity (LiFi), superfícies reconfigurables intel·ligents (RIS, per les sigles en anglès), comunicacions a la banda dels THz, etc. En concret, les RIS han despertat interès degut a la seva capacitat de manipular de forma precisa i programàtica les senyals de ràdio generades per diversos transmissors o punts d’accés i dirigir-les a múltiples receptors. Les manipulacions esmentades inclouen l’absorció de certs components de les ones incidents, o el control de la seva direcció, polarització, fase, o amplitud de forma selectiva en freqüència. En aquest context, les metasuperfícies (MSs) són part essencial de les RIS com a estructures artificials i planars que implementen la funció electromagnètica u òptica que la RIS necessita, que pot ser fins i tot anti-natural i atípica. Així doncs, els RIS consisteixen de dispositius que controlen les ones electromagnètiques (que podrien ser MS) co-integrades amb dispositius que doten a la MS de reconfigurabilitat i intel·ligència. Les MS, perla seva banda, estan composades de elements menor de la longitud d’ona que es coneixen coma “unit cells” o “meta-atoms”. El problema radica en que la promesa de les RIS, però, comporta una complexitat a nivell de MS que no és trivial. Per una banda, el rendiment de la RIS depèn de la mida de les unit cells, el número d’estats que pugui prendre la unit cell, o la mida de la MS completa. D’altra banda, hi ha problemes de costos i consum energètic associat amb la fabricació i operació de les RIS, que també depenen dels factors abans esmentats. Aquesta tesi té com a objectiu adreçar aquests problemes proposant un mètode per dimensionar les RIS mitjançant un anàlisi de l’escalabilitat de les MS programables, en un procés orientat a disseny. A més a més, s’espera que les MS tendeixen a tenir errors a mesura que es tornin més sofisticades i integrin més dispositius de control, sensat, o sintonització. No obstant, l’impacte d’aquests errors en el rendiment de les MS no està entesa del tot. En aquest aspecte, la tesi proposa un marc de treball per avaluar l’impacte de les fallades en el rendiment de MS programables, en un procés que distingeix els tipus d’error i la seva distribució espacial. Més enllà d’això, la complexitat de construir les RIS es pot amortitzar amb l’ús de dites RIS per manejar múltiples usuaris simultàniament. En aquesta direcció, la tesi introdueix un a tècnica de programació de les RIS basat en les lleis de la conservació dels moments i de la superposició d’ones, la qual dota a la MS la capacitat de generar i manejar múltiples feixos de manera independent. Finalment, tècniques d’aprenentatge automàtic en general, i les xarxes neuronals en particular, podrien ser útils en aquest context per mitjà de la seva capacitat d’aprendre relacions complexes entre conjunts de dades d’entrada i sortida així com de resoldre equacions diferencials sense tot el càlcul numèric associat. En aquesta direcció, la tesi proposa una solució basada en xarxes neuronals que estima, de manera acurada, el diagrama de radiació i/o diverses mètriques d’interès de la resposta d’una MS, amb l’objectiu d’ajudar en el disseny i programació de MS complexes
Arquitectura de Computadors

Les antennes reconfigurables offrent de multiples fonctions en changeant dynamiquement leurs propriétés telles que la fréquence de fonctionnement, la polarisation, le diagramme de rayonnement ou toute combinaison de ces trois paramètres. Leur agilité et leur diversité créent de nouvelles possibilités d'applications pour les systèmes radio tels que les réseaux locaux, les liaisons par satellite et notamment la radio cognitive. Dans cette thèse, deux antennes reconfigurables en fréquence fonctionnant dans les bandes des standards sans fil actuels ont été proposées. Elles sont basées sur la modification de la géométrie du patch rayonnant. Leurs dimensions ont été optimisées par algorithmes génétiques embarqués et combinés à un logiciel de simulation électromagnétique. La commande de la reconfiguration de ces antennes est réalisée à l'aide d'un microcontrôleur qui pilote l'état des commutateurs (des diodes PIN). De ce fait, un système d'antenne reconfigurable intelligent dédié à la radio cognitive a été développé.

Les antennes reconfigurables offrent de multiples fonctions en changeant dynamiquement leurs propriétés telles que la fréquence de fonctionnement, la polarisation, le diagramme de rayonnement ou toute combinaison de ces trois paramètres. Leur agilité et leur diversité créent de nouvelles possibilités d'applications pour les systèmes radio tels que les réseaux locaux, les liaisons par satellite et notamment la radio cognitive. Dans cette thèse, deux antennes reconfigurables en fréquence fonctionnant dans les bandes des standards sans fil actuels ont été proposées. Elles sont basées sur la modification de la géométrie du patch rayonnant. Leurs dimensions ont été optimisées par algorithmes génétiques embarqués et combinés à un logiciel de simulation électromagnétique. La commande de la reconfiguration de ces antennes est réalisée à l'aide d'un microcontrôleur qui pilote l'état des commutateurs (des diodes PIN). De ce fait, un système d'antenne reconfigurable intelligent dédié à la radio cognitive a été développé
Reconfigurable antennas offer multiple functions by dynamically changing their properties such as operating frequency, polarization, radiation pattern, and a combination of all these factors. Their agility and diversity create a wide range of different and new applications for radio systems such as local networks, satellites, and especially in cognitive radio. In this thesis, two new frequency reconfigurable antennas are proposed. The frequency reconfiguration is obtained by changing the geometry of radiating patch. Their dimensions have been optimized by genetic algorithm embedded in the electromagnetic simulation software. These antennas operate at the frequency band for IEEE 802.11b/g standard with satisfactory radiation characteristics. This thesis also presents a method of controlling the operation of the frequency reconfigurable antenna by a micro-controller. The operation of electronic switches (PIN diodes) are carried out through programs which allows an adaptive operating system like smart antennas and work well in cognitive radio environment

The present dynamic manufacturing environment has been characterized by a greater variety of products, shorter life-cycles of products and rapid introduction of new technologies, etc. Recently, a new manufacturing paradigm, i.e. Reconfigurable Manufacturing Systems (RMS), has emerged to address such challenging issues. RMSs are able to adapt themselves to new business conditions timely and economically with a modular design of hardware/software system. Although a lot of research has been conducted in areas related to RMS, very few studies on system-level control for RMS have been reported in literature. However, the rigidity of current manufacturing systems is mainly from their monolithic design of control systems. Some new developments in Information Technology (IT) bring new opportunities to overcome the inflexibility that shadowed control systems for years. Component-based software development gains its popularity in 1990â s. However, some well-known drawbacks, such as complexity and poor real-time features counteract its advantages in developing reconfigurable control system. New emerging Extensible Markup Language (XML) and Web Services, which are based on non-proprietary format, can eliminate the interoperability problems that traditional software technologies are incompetent to accomplish. Another new development in IT that affects the manufacturing sector is the advent of agent technology. The characteristics of agent-based systems include autonomous, cooperative, extendible nature that can be advantageous in different shop floor activities. This dissertation presents an innovative control architecture, entitled Component-based Intelligent Control Architecture (CICA), designed for system-level control of RMS. Software components and open-standard integration technologies together are able to provide a reconfigurable software structure, whereas agent-based paradigm can add the reconfigurability into the control logic of CICA. Since an agent-based system cannot guarantee the best global performance, agents in the reference architecture are used to be exception handlers. Some widely neglected problems associated with agent-based system such as communication load and local interest conflicts are also studied. The experimental results reveal the advantage of new agent-based decision making system over the existing methodologies. The proposed control system provides the reconfigurability that lacks in current manufacturing control systems. The CICA control architecture is promising to bring the flexibility in manufacturing systems based on experimental tests performed.
Ph. D.

Il progetto di tesi svolto riguarda lo studio di alcuni schemi di stima del canale di propagazione in presenza di superfici intelligenti riconfigurabili (comunemente chiamate RIS). Nel Capitolo 1 viene mostrato il vantaggio di adottare una RIS, mentre nel Capitolo 2 quest'ultima viene analizzata più nel dettaglio, introducendo anche il problema di stima del canale in scenari simili. Nel Capitolo 3 viene presentato lo stato dell'arte relativo ai principali approcci di stima del canale studiati in letteratura e viene analizzato nel dettaglio uno dei principali approcci ottimi validi nel caso di sistemi singola antenna, in cui la comunicazione viene assistita da una singola RIS, ed un secondo approccio valido nel caso di sistemi multi-antenna. Essendo il numero elevato di toni pilota necessari per la stima del CSI negli algoritmi presenti in letteratura il principale problema da affrontare, nel Capitolo 4 viene proposto un nuovo algoritmo, valido nel caso SISO, in grado di superare questo grosso limite. In particolare, viene analizzato il profilo di fase del canale sia in condizioni di campo lontano che campo vicino, e viene poi illustrato nel dettaglio come tali informazioni possono essere sfruttare per stimare il canale tramite un approccio ML. Le simulazioni che seguono, fanno vedere come un simile approccio sia in grado di ottenere delle valide stime delle informazioni di canale sfruttando solamente il 10/15$\%$ dei toni pilota necessari nell'approccio ottimo descritto nel Capitolo 3. Viene poi evidenziato come il problema di stima del canale sia equivalente al problema di stima della posizione del ricevitore. In particolare, note le posizioni del trasmettitore e della RIS adottata, viene illustrato un metodo (strettamente collegato all'approccio di stima del canale) di stima della posizione del ricevitore. Infine, nel Capitolo 5, vengono presentate le conclusioni e possibili sviluppi futuri correlati all'algoritmo proposto nel capitolo precedente.

Cette thèse porte principalement sur la modélisation, l'évaluation des performances et l'optimisation au niveau système des réseaux cellulaires de nouvelle génération à l'aide de la géométrie stochastique. En plus, la technologie émergente des surfaces intelligentes reconfigurables (RISs) est étudiée pour l'application aux futurs réseaux sans fil. En particulier, reposant sur un modèle d’abstraction basé sur la loi de Poisson pour la distribution spatiale des nœuds et des points d’accès, cette thèse développe un ensemble de nouveaux cadres analytiques pour le calcul d’importantes métriques de performance, telles que la probabilité de couverture et l'efficacité spectrale potentielle, qui peuvent être utilisés pour l'analyse et l'optimisation au niveau système. Plus spécifiquement, une nouvelle méthodologie d'analyse pour l'analyse de réseaux cellulaires tridimensionnels est introduite et utilisée pour l'optimisation du système. Un nouveau problème d’allocation de ressources est formulé et résolu en combinant pour la première fois géométrie stochastique et programmation non linéaire mixte en nombres entiers. L'impact du déploiement de surfaces réfléchissantes intelligentes sur un réseau sans fil est quantifié à l'aide de processus ponctuels, et les avantages potentiels des RISs contre le relais sont étudiés à l'aide de simulations numériques
The main focus of this thesis is on modeling, performance evaluation and system-level optimization of next-generation cellular networks by using stochastic geometry. In addition, the emerging technology of Reconfigurable Intelligent Surfaces (RISs) is investigated for application to future wireless networks. In particular, relying on a Poisson-based abstraction model for the spatial distribution of nodes and access points, this thesis develops a set of new analytical frameworks for the computation of important performance metrics, such as the coverage probability and potential spectral efficiency, which can be used for system-level analysis and optimization. More specifically, a new analytical methodology for the analysis of three-dimensional cellular networks is introduced and employed for system optimization. A novel resource allocation problem is formulated and solved by jointly combining for the first time stochastic geometry and mixed-integer non-linear programming. The impact of deploying intelligent reflecting surfaces throughout a wireless network is quantified with the aid of line point processes, and the potential benefits of RISs against relaying are investigated with the aid of numerical simulations

Thesis (M. Tech.) -- Central University of Technology, Free State, 2010
Traditional corrective maintenance is both costly and ineffective. In some situations it is more cost effective to replace a device than to maintain it; however it is far more likely that the cost of the device far outweighs the cost of performing routine maintenance. These device related costs coupled with the profit loss due to reduced production levels, makes this reactive maintenance approach unacceptably inefficient in many situations. Blind predictive maintenance without considering the actual physical state of the hardware is an improvement, but is still far from ideal. Simply maintaining devices on a schedule without taking into account the operational hours and workload can be a costly mistake. The inefficiencies associated with these approaches have contributed to the development of proactive maintenance strategies. These approaches take the device health state into account. For this reason, proactive maintenance strategies are inherently more efficient compared to the aforementioned traditional approaches. Predicting the health degradation of devices allows for easier anticipation of the required maintenance resources and costs. Maintenance can also be scheduled to accommodate production needs. This work represents the design and simulation of an intelligent maintenance management system that incorporates device health prognosis with maintenance schedule generation. The simulation scenario provided prognostic data to be used to schedule devices for maintenance. A production rule engine was provided with a feasible starting schedule. This schedule was then improved and the process was determined by adhering to a set of criteria. Benchmarks were conducted to show the benefit of optimising the starting schedule and the results were presented as proof. Improving on existing maintenance approaches will result in several benefits for an organisation. Eliminating the need to address unexpected failures or perform maintenance prematurely will ensure that the relevant resources are available when they are required. This will in turn reduce the expenditure related to wasted maintenance resources without compromising the health of devices or systems in the organisation.

Al giorno d'oggi le comunicazioni wireless hanno raggiunto un elevato livello di pervasività da essere presenti in tutto l'ambiente circostante. Sebbene la loro presenza abbia portato allo sviluppo di nuove tecnologie di comunicazione che favoriscono la mobilità, lo sfruttamento dello spettro radio degli ultimi decenni è stato intensivo. Il numero di dispositivi è aumentato notevolmente e con loro sono aumentate anche le richieste degli utenti in termini di data rate. Infatti la propagazione in ambienti caratterizzati da ostacoli, introduce riflessioni generando multipath che può essere più o meno ricco a seconda del numero di dispositivi in comunicazione o della densità di ostacoli. Questo tipo di fenomeno risulta essere particolarmente fastidioso perchè è causa di interferenze. Esistono diverse tecniche che permettono di fronteggiare il multipath, come ad esempio le modulazioni OFDM o che consentono di sfruttarlo, come nel caso dei sistemi MIMO-5G. In questo lavoro una nuova prospettiva è stata descritta: l'uso dei metamateriali. I metamateriali sono una nuova classe di materiali che, se opportunamente programmati, possono essere sfruttati per ottenere particolari coefficienti di riflessione. Inoltre, possono anche cambiare la fase dell'onda incidente. In questo scenario si apre la possibilità di poter installare nell'ambiente superfici composte da metamateriali dette metasuperfici, in modo da ottenere dei percorsi di riflessione del campo EM alternativi. Questa nuova tipologia di ambiente si differenzia dalla precedente concezione statica percepita come un avversario e viene definito intelligente. Da qui il concetto di smart environment, ovvero un'entità fisica completamente programmabile che permette all'utente di cambiare la risposta del canale arbitrariamente.

Les systèmes de contrôle des événements discrets ont la possibilité de résoudre les défis importants de la société moderne. En particulier, cela représente une solution fondamentale pour gérer et contrôler les nouvelles avancées technologiques en conformité avec la requis du développement durable. Le paramétrage, la configuration et la prise de décision de ces systèmes de contrôle sont des aspects critiques qui influent sur les performances et la productivité. Les approches d'architecture de contrôle dynamique, telles que les systèmes de contrôle reconfigurables, ont été proposées pour la modélisation de ces systèmes. Cependant, ils n'ont pas réussi à optimiser le processus de reconfiguration car celles-ci se concentrent sur la continuité de l'exécution plutôt que sur l'optimisation de la reconfiguration. Cette dissertation propose une architecture de référence pour un système de contrôle reconfigurable, nommé Pollux, conçu pour gérer et ajuster de manière optimale et en temps réel l'architecture d'un système de contrôle, soit pour guider l'exécution opérationnelle ou répondre à une perturbation du système. En considérant une proposition d'une configuration optimale des architectures de contrôle basées sur la gouvernance partagée, cette approche proposée un système de contrôle reconfigurable compose d’une entité décisionnelle flexible et personnalisable, d’une représentation qui caractérise la configuration unique et la solution de contrôle de l'architecture de contrôle et d’un mécanisme de reconfiguration à trois modules qui intègre les principes basés sur l'optimalité dans la reconfiguration. Notre approche est appliquée dans le domaine de la fabrication et est validée dans une simulation et une cellule réelle de fabrication située à l'Université de Valenciennes, en France. La validation effectuée dans trois scénarios expérimentaux a permis de vérifier les avantages de notre approche et de nous encourager à continuer la recherche
Discrete-event control systems have the opportunity to resolve significant challenges of modern society. In particular, these represent a fundamental solution to manage and control the new technological advances in compliance to the increased consciousness of sustainable development. The parameterization, configuration and decision-making of these control systems are critical aspects that impact the performance and productivity required. Dynamic control architecture approaches, such as reconfigurable control systems, have been proposed for modelling such systems. However, such approaches have failed to address the recovery of the reconfiguration process as these focus on the continuity of execution rather than on the optimisation of the reconfiguration. This dissertation proposes a reference architecture for a reconfigurable control system, named Pollux, designed to manage and adjust optimally and in real time the architecture of a control system, either to guide operational execution or to respond to a system perturbation. Considering a proposed framework of an optimal configuration of control architectures based on shared governance, this proposed approach aims to orchestrate a flexible and customizable decisional entity, a representation that characterize the unique configuration and control solution of the control architecture, and a three-module reconfiguration mechanism that integrates the optimality-based principles into the reconfiguration process, to ensure a recovery of global performance and/or minimise the degradation caused by perturbations. Our approach is applied in the manufacturing domain and is validated in a simulation and a real flexible manufacturing system cell located at the University of Valenciennes, France. The validation conducted in three experimental scenarios verified the benefits of our approach and encourage us to continue research in this direction

Nous nous intéressons au diagnostic de systèmes à événements discrets modélisés par un automate. Pour pouvoir prendre en compte des observations incertaines, nous les représentons sous la forme d'un automate. Le diagnostic est alors défini comme la synchronisation des deux automates. Pour permettre un calcul incrémental et en-ligne du diagnostic, nous définissons une structure appelée chaîne d'automates qui représente les observations par périodes appelées fenêtres.
Le diagnostic peut s'effectuer sur chacune de ces périodes, et on peut raffiner le résultat en vérifiant l'égalité entre l'état final d'une fenêtre et l'état initial de la suivante. Puisque le modèle global d'un système réel est trop grand pour être calculé, nous avons adapté les techniques de diagnostic décentralisé à notre approche. Enfin, nous avons étendu nos résultats aux systèmes reconfigurables, c'est-à-dire dont certains composants ainsi que les connexions entre ceux-ci peuvent être ajoutés, modifiés ou supprimés.

Thesis (MScEng)--Stellenbosch University, 2013.
ENGLISH ABSTRACT: The thesis evaluates control strategies for reconfigurable manufacturing systems by using a welding assembly cell as a case study. The cell consists of a pallet magazine, conveyor, feeder subsystem (comprising an articulated robot and singulation unit), welder subsystem (which uses a modular Cartesian robot), and inspection and removal subsystems. The research focuses on control strategies that enhance reconfigurability in terms of structure, hardware and software using agent-based control and the IEC 61499 standard, based on PC control. Reconfiguration may occur when a new product is introduced, as well as when a new subsystem is introduced or removed from the production cell. The overall control architecture is that the subsystems retain no knowledge of the product, but product information resides in the cell controller, while services offered by the subsystems are registered with the directory facilitator of the Java agent platform. The control strategies are implemented on the modular Cartesian weld robot and the cell controller for assembly cell. A layered architecture with low-level control and high-level control is used to allow separation of concerns and rapid changes in both hardware and software components. The low-level control responds in hard real-time to internal and external events, while the high-level control handles soft real-time actions involving coordination of control related issues. The results showed IEC 61499 function blocks to be better suited to low-level control application in distributed systems, while agents are more suited for high-level control. Modularity in software components enhances hardware and software scalability. Additionally, agents can support online reconfiguration of reconfigurable machines.
AFRIKAANSE OPSOMMING: Die tesis evalueer beheerstrategieë vir herkonfigureerbare vervaardigingstelsels deur gebruik te maak van ’n sweismonteersel as ’n gevallestudie. Die sel bestaan uit ’n palletmagasyn, vervoerbande, voersubstelsel (bestaande uit ’n geartikuleerde robot en singulasie-eenheid), sweissubstelsel (wat gebruik maak van ’n modulêre Cartesiese robot), en inspeksie- en verwyderingsubstelsels. Die navorsing fokus op beheerstrategieë wat herkonfigureerbaarheid verhoog in terme van struktuur, hardeware en sagteware met behulp van agent-gebaseerde beheer en die IEC 61499 standaard, wat gebaseer is op PC-beheer. Herkonfigurasie mag voorkom wanneer ’n nuwe produk in-gestel word, sowel as wanneeer ’n nuwe substelsel bygevoeg of verwyder word van die produksiesel. Die oorhoofse beheerargitektuur is dat die substelsels geen kennis van die produk hou nie, maar die produkinligting in die selbeheerder geberg, terwyl dienste wat aangebied word deur die substelsels wat geregistreer is by die gidsfasiliteerder van die Java agent platform. Die beheerstrategië is geïmplementeer op die modulere Cartesiese sweisrobot en die selbeheerder vir die monteersel. ’n Gelaagde argitektuur met ’n lae-vlak beheer en hoë-vlak beheer word gebruik om skeiding van oorwegings en vinnige veranderinge in beide hardeware en sagteware komponente toe te laat. Die lae-vlak beheer reageer hard intyds op interne en eksterne gebeure, terwyl die hoë-vlak beheer sag intyds die koördinering van beheerverwante kwessies hanteer. Die resultate het getoon dat IEC 61499 funksie-blokke beter geskik is vir lae-vlak beheer toepassing in verspreide stelsels, terwyl agente meer geskik is vir hoë-vlak beheer. Modulariteit in sagteware komponente verhoog hardeware en sagteware skaleerbaarheid. Boonop kan agente ook aanlyn herkonfigurasie van herkonfigureerbare masjiene ondersteun.

Les Réseaux de Neurones Convolutifs profonds (CNNs) ont connu un large succès au cours de la dernière décennie, devenant un standard de la vision par ordinateur. Ce succès s’est fait au détriment d’un large coût de calcul, où le déploiement des CNNs reste une tâche ardue surtout sous des contraintes de temps réel.Afin de rendre ce déploiement possible, la littérature exploite le parallélisme important de ces algorithmes, ce qui nécessite l’utilisation de plate-formes matérielles dédiées. Dans les environnements soumis à des contraintes de consommations énergétiques, tels que les nœuds des caméras intelligentes, les cœurs de traitement à base de FPGAs sont reconnus comme des solutions de choix pour accélérer les applications de vision par ordinateur. Ceci est d’autant plus vrai pour les CNNs, où les traitements se font naturellement sur un flot de données, rendant les architectures matérielles à base de FPGA d’autant plus pertinentes. Dans ce contexte, cette thèse aborde les problématiques liées à l’implémentation des CNNs sur FPGAs. En particulier, ces travaux visent à améliorer l’efficacité des implantations grâce à deux principales stratégies d’optimisation; la première explore le modèle et les paramètres des CNNs, tandis que la seconde se concentre sur les architectures matérielles adaptées au FPGA
Deep Convolutional Neural Networks (CNNs) have become a de-facto standard in computer vision. This success came at the price of a high computational cost, making the implementation of CNNs, under real-time constraints, a challenging task.To address this challenge, the literature exploits the large amount of parallelism exhibited by these algorithms, motivating the use of dedicated hardware platforms. In power-constrained environments, such as smart camera nodes, FPGA-based processing cores are known to be adequate solutions in accelerating computer vision applications. This is especially true for CNN workloads, which have a streaming nature that suits well to reconfigurable hardware architectures.In this context, the following thesis addresses the problems of CNN mapping on FPGAs. In Particular, it aims at improving the efficiency of CNN implementations through two main optimization strategies; The first one focuses on the CNN model and parameters while the second one considers the hardware architecture and the fine-grain building blocks

Le développement des antennes modales, qui sont des antennes actives reconfigurables en diagramme de rayonnement mais pas en réseaux, a commencé pour pouvoir implémenter le dépointage électronique dans les téléphones portables. Cette solution est généralement réalisée par un réseau d’antennes, ce qui est très difficile, voire impossible, dans un téléphone portable. Le dépointage permettrait d’améliorer le bilan de liaison et d’augmenter le débit des données.Le premier objectif de cette thèse est donc de développer des antennes modales pour la norme LTE. Trois concepts d’antennes modales ont été présentés. Le premier est une antenne de type « folded loop » active reconfigurable par permutation des points d’alimentation et de retour à la masse. Le deuxième propose une architecture pour rassembler l’antenne principale et l’antenne diversité en bas du téléphone, tout en supportant le MIMO et l’agrégation de porteuses, deux des spécificités de la LTE. Le dernier optimise l’utilisation de la seconde antenne des systèmes LTE MIMO pour procéder au dépointage électronique.Ces antennes modales ne peuvent délivrer leur réel potentiel qu’en étant utilisées avec un algorithme de pilotage, qui choisira la configuration ou le mode approprié(e) à la situation. Le second objectif de cette thèse est donc le développement d’algorithmes intelligents de pilotage d’antennes modales. Le premier algorithme développé et breveté par la société Ethertronics a la particularité de prédire à chaque instant quel sera le meilleur mode à l’instant suivant, à l’aide de données en bande de base pour la LTE. Le second algorithme est déterministe et permet d’estimer et de suivre la direction d’arrivée du signal. Il sélectionne ensuite le mode qui possède le meilleur gain dans cette direction, dans le but d’améliorer le bilan de liaison
The development of modal antennas which are radiation pattern reconfigurable active antennas, but not arrays, started in order to implement beam forming in cellphones. This solution is generally made with an antenna array, which is very difficult, even impossible, in a mobile phone. Beam forming could improve the link budget and increase the data rate. The first aim of this thesis is the development of modal antennas for LTE standard. Three modal antennas concepts were presented. The first one is a reconfigurable “folded loop” active antenna by permutation of feed and ground points. The second one is a solution to gather the main and the diversity antenna in the bottom part of the phone, and to support MIMO and carrier aggregation, which are two features of LTE. The last one optimizes the use of the second antenna in LTE MIMO systems in order to perform beam forming. These modal antennas will provide their real potential only by being used by a driving algorithm which will choose the best mode or configuration according to the situation. So, the second aim of this thesis is the development of smart modal antenna driving algorithms. The first algorithm, developed and patented by Ethertronics, has the specificity to predict, at each moment, which mode will be the best for the next moment, by using baseband data for LTE. The second algorithm is deterministic and can estimate and track the direction of arrival of the signal. Then, it selects the mode which has the best gain in this direction in order to improve the link budget

Les travaux de recherche présentés dans ce mémoire consistent en une étude pour le concept de la vision active et de la perception multisensorielle, et en la réalisation d'une plate-forme modulaire et reconfigurable adaptée à la perception multisensorielle, ainsi que l'implantation d'un algorithme de détection de mouvement et de poursuite d'objet. Ces travaux se découpent en deux parties. Nous nous intéressons tout d'abord aux problèmes de la vision par ordinateur. Une synthèse bibliographique des principaux développements des systèmes de vision passives et actives, des architectures parallèles et de la vision classique est effectuée au début de ce mémoire, et ce qui permet ensuite de mettre en évidence les problèmes liés au système de vision classique et de proposer un nouveau système de vision, une plate-forme CIT, adaptée à la perception multisensorielle. Les éléments constitutifs de la plate-forme CIT permettent de réaliser facilement une architecture DMIMD et/ou Sial , de s'inspirer de certaines caractéristiques de la vision humaine tout en respectant les contraintes générales du système : faible consommation, faible encombrement, faible coût et modularité. L'architecture du système proposée tant sur le plan théorique que sur le plan pratique répond à la nécessité essentielle d'un système de perception multisensorielle : le traitement de signaux en temps réel. Puis nous abordons l'étude des algorithmes de détection de mouvement et de poursuite d'objet. Dans ce mémoire, nous avons proposé un nouvel algorithme : CAES basé sur la technique de détection d'énergie. Les résultats obtenus jusqu'alors montrent que cet algorithme est assez robuste, rapide et précis pour la tâche de la détection de mouvement et de la poursuite d'un objet. L'implantation de cet algorithme a été faite sur la plate-forme CIT. De plus, cet algorithme a été étudié pour être implanté dans un circuit VLSI monopuce à base de la technologie FPGA et fonctionné à la cadence vidéo
The work presented in this thesis consists of the study of the concept of active vision and multi-sensor perception, the realization of a modular reconfigurable platform adapted to the multi-sensor perception, and the implementation of the motion tracking algorithm. This work is also one part of the project “A parallel reconfigurable plat-form dedicated for omni-directional perception”. This work is divided into two parts. Firstly, we have dealt with the CIT plat-form architecture. A survey on the passive & active vision and the parallel architecture is presented in the beginning of the thesis. That allows to discover the problems in the existing computer vision systems for real-time task and to draw up a new vision system based on the concept of multi-sensor perception. To respect the general constraints : low consumption, low congestion, low cost and flexible, the plat-form permits to be inspired from some characteristics of the human vision to overcome the problems existing in the traditional system, to construct easily the DMIMD/SMIMD architectures. Consequently, it is able to carry out the vision tasks in real-time. Secondly, we have developed one application adapted to the CIT plat-form, that is the motion detection and tracking moving objet. In fact the current trend in optical flow research is to stress accuracy under ideal conditions and not to consider computational resource requirements or temporal constraint, which are essential for real-time tasks. As a result, practical applications for optical flow algorithms remain scarce. Algorithms based on the token matching and block matching have been shown to be fast in practice but are in general infeasible due to their severe environment requirement. This thesis has proposed a new algorithm CAES for active camera based on the energy detection algorithm. The experimental results show that it is robust, fast and precise for the motion detection and tracking. The algorithm will be implemented in a mono-chip VLSI by using the FPGA technology, which permits to execute it at video rate

Cette thèse a été consacrée à la conception d'antennes volumiques reconfigurables pour les produits sans fils du futur. Ces recherches ont été motivées par la tendance actuelle conduisant à une centralisation des services au sein des réseaux locaux sans fil et une miniaturisation des dispositifs. Ceci se traduit par une contrainte d'encombrement pour les antennes qui se doivent également d'apporter des solutions aux problèmes d'affaiblissements dus aux trajets multiples et aux interférences tout en améliorant les capacités (portée, qualité, consommation) du dispositif. Nous présentons ainsi une solution d'antenne multi-secteurs associant plusieurs antennes Vivaldi en réponse aux problèmes de l'application visée à savoir un système embarqué de type caméra haute définition sans fil. Après une étude théorique de l'antenne Vivaldi, un nouveau concept d'antenne multi-secteurs a été introduit et validé. La nécessité d'une réalisation industrielle à grande échelle et à bas coût de formes complexes nous a conduit vers la technologie plastique métallisé pour fabriquer l'antenne. Un système original de report sans soudure a ainsi été développé pour intégrer l'antenne en plastique au reste du système. La caractérisation d'un prototype a permis de valider l'utilisation du plastique pour ce genre d'applications. Cette antenne a ensuite été intégrée à une caméra sans fil puis recouverte d'un radôme protecteur qui permet d'améliorer les performances. Cette intégration simplifiée associée au contrôle des performances et à la flexibilité de l'antenne permet d'envisager des utilisations dans des applications aussi diverses que les réseaux domestiques ou maillés, ou pour la technologie MIMO
This thesis is dedicated to the design of 3D smart antennas for forthcoming wireless devices. Our research work has been motivated by the actual wireless trends leading to service concentration within WLAN and device miniaturisation. Thus, antenna design is nowadays guided by size constraints and their capacity to deal with fading interference, wireless environments while improving the performances of devices in terms of communication quality, power consumption. This thesis presents a multi-sector antenna solution associating many Vivaldi-antennas to provide a solution for the targeted application which is an embedded system constituting of high definition wireless cameras. A theoretical analysis of the Vivaldi antenna is first performed and then a novel concept of multi-sector antenna has been introduced and validated. Then, in order to target consumer market and to reduce the manufacturing costs in high volume production, the metallized molded plastic technology which enables molding 3D complex structures has been retained. An original without-welding transfer system has been developed for integrating the antenna to the rest of the system. The characterization of a prototype has resulted in the validation of the use of plastics for such applications. This antenna has been integrated in a wireless camera ; a protective radome having as additional property to improve the overall performances of the device is finally designed. This simplified integration procedure associated to a monitoring of the performances and the flexibility of the system makes it a good candidate for various applications like domestic WLAN, mesh networks or for MIMO technology

The thesis is focused on the description of Metamaterials and Metasurfaces, as well as their development, in order to process signals at the electromagnetic level using a variety of approaches that reduce latency, complexity, power consumption, and cost.

Yes
Cooperative Systems of Systems (CSoS) including Autonomous systems (AS), such as autonomous cars and related smart traffic infrastructures form a new technological frontier for their enormous economic and societal potentials in various domains. CSoS are often safety-critical systems, therefore, they are expected to have a high level of dependability. Due to the open and adaptive nature of the CSoS, the conventional methods used to provide safety assurance for traditional systems cannot be applied directly to these systems. Potential configurations and scenarios during the evolving operation are infinite and cannot be exhaustively analysed to provide guarantees a priori. This paper presents a novel framework for dynamic safety assurance of CSoS, which integrates design time models and runtime techniques to provide continuous assurance for a CSoS and its systems during operation.
Dependability Engineering Innovation for Cyber Physical Systems (DEIS) H2020 Project under Grant 732242.

Dissertação de Mestrado Integrado em Engenharia Electrotécnica e de Computadores apresentada à Faculdade de Ciências e Tecnologia
Nos últimos anos, temos visto a expanção da inteligência artificial em diferentes áreas e dispositivos. No entanto, no ecossistema IoT, temos uma tendência constante a usar a computação na nuvem para armazenar e processar as vastas quantidades de dados geradas por estes dispositivos, devido aos recursos locais limitados. Esta dissertação propõe a implementa çãao de dispositivos IoT inteligentes capazes de fornecer informações específicas a partir de dados produzidos a partir de algum sensor, por exemplo uma câmara ou microfone, em vez dos próprios dados brutos. O foco será o processamento de imagens usando CNNs. Essa abordagem é claramente distinta das tendências atuais em dispositivos IoT que usam computação na nuvem para processar os dados produzidos. Pretendemos uma viragem no paradigma estabelecido e procuramos uma abordagem deedge computing. Como o foco ser ão dispositivos pequenos e simples, precisamos de uma solução de baixa potência para o cálculo da CNN. Os dispositivos SoC ganharam popularidade devido à sua heterogeneidade. Este trabalho usará um sistema que combina uma unidade de processamento ARM em conjunto com a FPGA, mantendo baixa potência e aproveitando a FPGA para obter um alto desempenho. O HADDOC2 será usado como uma ferramenta que converterá o código CNN em VHDL para ser sintetizado na FPGA, enquanto no ARM haverá um sistema que irá gerir todo o processo usando pontes de comunicação com a FPGA e protocolos de comunicação IoT para enviar as informações processadas. No fim é obtido um sistema com uma CNN implementada na FPGA o usando o HPS como gestor de todo o processo e que se comunica com o exterior através do MQTT.
In recent years we have seen the emergence of AI in wider application areas and in more devices. However, in the IoT ecosystem there is the tendency to use cloud computing to store and process the vast amounts of information generated by these devices, due to the limited local resources. This dissertation proposes the implementation of smart IoT devices able to provide specific information from raw data produced from some sensor, e.g. a camera or microphone, instead of the raw data itself. The focus will be embedded image processing using Convolutional Neuronal Networks (CNN). This approach is clearly distinct from the current trends in IoT devices that use cloud computing to process the collected data. We intend a twist on the established paradigm and pursue an edge computing approach. Since we are targeting small and simple devices, we need some low power solution for the CNN computation. SoC devices have gained popularity due to their heterogeneity. In our work we use a system that combines an ARM processing unit in conjunction with FPGA, while maintaining low power, taking advantage of FPGA to achieve high performance.HADDOC2 will be used as a tool that will convert CNN to VHDL code to be synthesized to FPGA, while in ARM there will be a system that will manage the entire process using IoT communication protocols to send the processed information. A system with a CNN implemented in the FPGA is obtained using HPS as the manager of the entire process and then this system communicates with the outside through MQTT.

Fuzzy logic systems (FLSs) are well known in the literature for their ability to model linguistics and system uncertainties. Due to this ability, FLSs have been successfully used in modeling and control applications such as medicine, finance, communications, and operations research. Moreover, the ability of higher order fuzzy systems to handle system uncertainty has become an interesting topic of research in the field. In particular, type-2 FLSs (T2 FLSs), systems consisting of fuzzy sets with fuzzy grades of membership, a feature that type-1 (T1) does not offer, are most well-known for this capability. The structure of T2 FLSs allows for the incorporation of uncertainty in the input membership grades, a common situation in reasoning with physical systems. General T2 FLSs have a complex structure, thus making them difficult to adopt on a large scale. As a result, interval T2 FLSs (IT2 FLSs), a special class of T2 FLSs, have recently shown great potential in various applications with input-output (I/O) system uncertainties. Due to the sophisticated mathematical structure of IT2 FLSs, little to no systematic analysis has been reported in the literature to use such systems in control design. Moreover, to date, designers have distanced themselves from adopting such systems on a wide scale because of their design complexity. Furthermore, the very few existing control methods utilizing IT2 fuzzy logic control systems (IT2 FLCSs) do not guarantee the stability of their system. Therefore, this thesis presents a systematic method for designing stable IT2 Takagi-Sugeno-Kang (IT2 TSK) fuzzy systems when antecedents are T2 fuzzy sets and consequents are crisp numbers (A2-C0). Five new inference mechanisms are proposed that have closed-form I/O mappings, making them more feasible for FLCS stability analysis. The thesis focuses on control applications for when (a) both plant and controller use A2-C0 TSK models, and (b) the plant uses T1 Takagi-Sugeno (T1 TS) and the controller uses IT2 TS models. In both cases, sufficient stability conditions for the stability of the closed-loop system are derived. Furthermore, novel linear matrix inequality-based algorithms are developed for satisfying the stability conditions. Numerical analyses are included to validate the effectiveness of the new inference methods. Case studies reveal that a well-tuned IT2 TS FLCS using the proposed inference engine can potentially outperform its T1 TSK counterpart, a result of IT2 having greater structural flexibility than T1. Moreover, due to the simple nature of the proposed inference engine, it is easy to implement in real-time control systems. In addition, a novel design methodology is proposed for IT2 TSK FLC for modular and reconfigurable robot (MRR) manipulators with uncertain dynamic parameters. A mathematical framework for the design of IT2 TSK FLCs is developed for tracking purposes that can be effectively used in real-time applications. To verify the effectiveness of the proposed controller, experiments are performed on an MRR with two degrees of freedom which exhibits dynamic coupling behavior. Results show that the developed controller can outperform some well-known linear and nonlinear controllers for different configurations. Therefore, the proposed structure can be adopted for the position control of MRRs with unknown dynamic parameters in trajectory-tracking applications. Finally, a rigorous mathematical analysis of the robustness of FLSs (both T1 and IT2) is presented in the thesis and entails a formulation of the robustness of FLSs as a constraint multi-objective optimization problem. Consequently, a procedure is proposed for the design of robust IT2 FLSs. Several examples are presented to demonstrate the effectiveness of the proposed methodologies. It was concluded that both T1 and IT2 FLSs can be designed to achieve robust behavior in various applications. IT2 FLSs, having a more flexible structure than T1 FLSs, exhibited relatively small approximation errors in the several examples investigated. The rigorous methodologies presented in this thesis lay the mathematical foundations for analyzing the stability and facilitating the design of stabilizing IT2 FLCSs. In addition, the proposed control technique for tracking purposes of MRRs will provide control engineers with tools to control dynamic systems with uncertainty and changing parameters. Finally, the systematic approach developed for the analysis and design of robust T1 and IT2 FLSs is of great practical value in various modeling and control applications.

As comunicações na banda Terahertz (THz) são consideradas uma tecnologia crucial para a transmissão de dados a velocidades ultra-elevadas em sistemas de comunicação sem fios da futura geração. As extensas larguras de banda disponíveis nas frequências de THz têm o custo de graves perdas de propagação e limitações de potência, o que resulta em distâncias de comunicação muito curtas. Superfícies inteligentes reconfiguráveis (RIS) são uma tecnologia promissora para ultrapassar esta limitação uma vez que têm capacidade para moldar as ondas THz, ajustando adequadamente as mudanças de fase. Esta dissertação foca-se no estudo de um sistema eficaz em contexto de ambiente para as comunicações sem fio THz. Na presente dissertação concebemos um sistema de comunicação sem fios ultra-massivo de múltiplas entradas e saídas (UM-MIMO) assistido por RIS. Para maximizar a taxa alcançável do sistema, e ao mesmo tempo que se lida com a grande configuração de problemas que é típica dos sistemas UM-MIMO assistidos por RIS, é desenvolvido um algoritmo de gradiente proximal acelerado (APG) de baixa complexidade para o cálculo das mudanças de fase dos elementos do RIS. Também se considera a pré-codificação híbrida, a qual é necessária para tornar viável a implementação de comunicações UM-MIMO nos THz, e avalia-se a incidência de não-idealidades que são típicas na implementação prática do sistema. Os resultados numéricos demonstram que quanto maior o RIS maior taxa de dados o sistema alcança, e que o mesmo deve ficar situado na vizinhança do recetor ou do transmissor. A eficácia do algoritmo proposto também é comprovada, mesmo quando se considera a quantização realista das mudanças de fase discretas e o conhecimento imperfeito do canal.
Terahertz (THz)-band communications are considered a crucial technology for ultrahigh data rate transmission in future-generation wireless communication systems. The extensive available bandwidths at THz frequencies come at the cost of severe propagation losses and power limitations, which results in very short communication distances. Reconfigurable intelligent surfaces are a promising technology to overcome this limitation as they can be used to shape THz waves by adequately adjusting the phase shifts. This dissertation focuses on the study of an effective system for THz wireless communications environment. In this dissertation, we design a RIS-assisted ultra-massive multiple-input multiple-output (UM-MIMO) wireless communication system. To maximize the achievable rate of the system, while coping with the large problem setting that is typical in RIS-aided UM-MIMO systems, a low complexity accelerated proximal gradient (APG) algorithm is developed for computing the phase-shifts of the RIS elements. We also consider the adoption of hybrid precoding which is necessary for viable UM-MIMO THz implementations and evaluate the impact of non-idealities that are typical in practical implementations of the system. Numerical results demonstrate that the larger the RIS is, the higher data rate the system achieves, and that it should be located in the vicinity of the receiver or transmitter. The effectiveness of the proposed algorithm is also proven, even when considering realistic quantization of discrete phase shifts and imperfect channel knowledge.