In the emerging industry of small unmanned vehicles, pioneered by small businesses and research institutions, a suitable combat system test platform is needed. Computer simulations are useful, but do not provide the definitive proof of effective operation necessary for deployment of a combat system. What is needed is an affordable simulated weapons system that enables live flight testing without the used of live weaponry. A framework is developed here for the construction of a simulated weapon using Free Space Optical (FSO) infrared communication. It is developed in such a way to ensure compatibility with a variety of platforms including ground and aerial vehicles, so that identical but configurable modules can be used on any vehicle that is to take place in a live combat simulation. A proof-of-concept implementation of this modular laser combat system framework is also presented and tested. The implemented system shows the value of such a simulated weapons system and future areas of improvement are also explored.

Electromagnetic interference (EMI) is one of the most common problems encountered in microwave applications. Interaction of electromagnetic (EM) waves from different sources may result in device malfunction due to misinterpretation of the transferred data or information loss. On the other hand, development of materials with reduced radar detectability is desired in defense applications. Considering the limitations in weight and thickness, development of lightweight structural materials with enhanced electromagnetic absorption potential is needed. In this study, development and characterization of glass fiber-reinforced polymer (GFRP) composite materials to be used in EM wave absorbing or EMI shielding applications was aimed. Incorporation of electromagnetic wave absorption characteristic has been achieved by the application of conductive thin film on fiber glass woven fabric reinforcement layers. Characterization of EM wave absorption potential was conducted using &ldquo / free-space method&rdquo / in 18 &ndash / 27 GHz frequency range. Single and multilayered combinations of surface-modified fiber glass woven fabrics were characterized in terms of their EM wave interaction properties and design principles for efficient broadband EM wave absorbing multilayered GFRP composite material have been presented. A computer aided computation method has also developed in order to predict EM wave transmission, reflection, and hence absorption characteristics of multilayered structures from single layer properties. Estimated results were verified compared to free-space measurement results. In the current study, up to 85% electromagnetic wave absorption has been obtained within 18-27 GHz frequency range (K band). Enhancement of EM wave absorption potential of multilayer structure has also been demonstrated by computer aided computation.

Over the last ten years, the number of laptop computers, personal digital assistants (PDAs) and other mobile terminals has massively increased. This evolution has led to a huge demand of wireless communications, in the purpose of avoiding wires and connectors to supply mobility in various places such as offices, homes, rail stations or airports. To date, this mobility is mainly offered by radiofrequency (RF) communications using Wi-Fi channels, with a maximum bitrate of 300 Mbps. However, new indoor applications such as non-compressed high-definition (HD) video transfer or remote hard-disk backup require much higher bandwidths (> 2Gbps). Such a bitrate can be transmitted using an optical wireless communications OWC system. In this thesis, a new architecture of OWC has been proposed and studied according to the GROWTH criteria (GReen Optical Wireless InTo Home network). This architecture is based on distributed free-space optical pico-cells in each room of the home interconnected by optical fibers and offering bitrates that exceed 1 Gbps. The work is divided into four parts: dimensioning of the systems and the selection of associated opto-electronics technologies, simulation of the hybrid optical channel (fiber optics + free-space) using the VPI Transmission Maker and Matlab softwares, choice of the wavelength and finally the experimental measurements to validate the performance of the system.

Wireless communication is facing an increasingly severe spectrum scarcity problem. Hybrid free space optical (FSO)/ millimetre wavelength (MMW) radio frequency (RF) systems and cognitive radios are two candidate solutions. Hybrid FSO/RF can achieve high data rate transmission for wireless back haul. Cognitive radio transceivers can opportunistically access the underutilized spectrum resource of existing systems for new wireless services. In this work we carry out accurate performance analysis on these two transmission techniques. In particular, we present and analyze a switching based transmission scheme for a hybrid FSO/RF system. Specifically, either the FSO or RF link will be active at a certain time instance, with the FSO link enjoying a higher priority. We consider both a single threshold case and a dual threshold case for FSO link operation. Analytical expressions are obtained for the outage probability, average bit error rate and ergodic capacity for the resulting system. We also investigate the delay performance of secondary cognitive transmission with interweave implementation. We first derive the exact statistics of the extended delivery time, that includes both transmission time and waiting time, for a fixed-size secondary packet. Both work-preserving strategy (i.e. interrupted packets will resume transmission from where interrupted) and non-work-preserving strategy (i.e. interrupted packets will be retransmitted) are considered with various sensing schemes. Finally, we consider a M/G/1 queue set-up at the secondary user and derive the closed-form expressions for the expected delay with Poisson traffic. The analytical results will greatly facilitate the design of the secondary system for particular target application. / Graduate

Quelques aspects de la géométrie des espaces LipschitzEn premier lieu, nous donnons les propriétés fondamentales des espaces Lipschitz libres. Puis, nous démontrons que l'image canonique d'un espace métrique M est faiblement fermée dans l'espace libre associé F(M). Nous prouvons un résultat similaire pour l'ensemble des molécules.Dans le second chapitre, nous étudions les conditions sous lesquelles F(M) est isométriquement un dual. En particulier, nous généralisons un résultat de Kalton sur ce sujet. Par la suite, nous nous focalisons sur les espaces métriques uniformément discrets et sur les espaces métriques provenant des p-Banach.Au chapitre suivant, nous explorons le comportement de type l1 des espaces libres. Entre autres, nous démontrons que F(M) a la propriété de Schur dès que l'espace des fonctions petit-Lipschitz est 1-normant pour F(M). Sous des hypothèses supplémentaires, nous parvenons à plonger F(M) dans une somme l_1 d'espaces de dimension finie.Dans le quatrième chapitre, nous nous intéressons à la structure extrémale de $F(M)$. Notamment, nous montrons que tout point extrémal préservé de la boule unité d'un espace libre est un point de dentabilité. Si F(M) admet un prédual, nous obtenons une description précise de sa structure extrémale.Le cinquième chapitre s'intéresse aux fonctions Lipschitziennes à valeurs vectorielles. Nous généralisons certains résultats obtenus dans les trois premiers chapitres. Nous obtenons également un résultat sur la densité des fonctions Lipschitziennes qui atteignent leur norme. / Some aspects of the geometry of Lipschitz free spaces.First and foremost, we give the fundamental properties of Lipschitz free spaces. Then, we prove that the canonical image of a metric space M is weakly closed in the associated free space F(M). We prove a similar result for the set of molecules.In the second chapter, we study the circumstances in which F(M) is isometric to a dual space. In particular, we generalize a result due to Kalton on this topic. Subsequently, we focus on uniformly discrete metric spaces and on metric spaces originating from p-Banach spaces.In the next chapter, we focus on l1-like properties. Among other things, we prove that F(M) has the Schur property provided the space of little Lipschitz functions is 1-norming for F(M). Under additional assumptions, we manage to embed F(M) into an l1-sum of finite dimensional spaces.In the fourth chapter, we study the extremal structure of F(M). In particular, we show that any preserved extreme point in the unit ball of a free space is a denting point. Moreover, if F(M) admits a predual, we obtain a precise description of its extremal structure.The fifth chapter deals with vector-valued Lipschitz functions.We generalize some results obtained in the first three chapters.We finish with some considerations of norm attainment. For instance, we obtain a density result for vector-valued Lipschitz maps which attain their norm.

Godefroy et Ozawa ont montré qu’il existe un espace compact dont l’espace libre n’a pas la propriété d’approximation. Il est donc naturel de se demander quels sont les espaces métriques dont l’espace libre à la propriété d’approximation bornée. Grothendieck a montré qu’un dual séparable ayant la propriété d’approximation a la propriété d’approximation métrique. Ce résultat justifie l’utilité de savoir si un espace libre est un dual. Le premier chapitre est consacré à la dualité. Pour commencer nous présentons un théorème permettant de montrer qu’un espace de Banach séparable est le dual d’un sous-espace de son dual, sous conditions. Nous expliquons ensuite comment appliquer ce théorème dans le cadre des espaces libres. Dans la suite du chapitre nous l’appliquons aux espaces propres dénombrables ou ultramétriques. Dans le deuxième chapitre nous nous intéressons à la propriété d’approximation métrique sur l’espace libre des espaces propres dénombrables. Nous énonçons tout d’abord un résultat dû à Kalton puis nous l’utilisons pour montrer que sous ces hypothèses, l’espace libre a la propriété d’approximation métrique. Le troisième chapitre est dédié à l’étude des espaces libres sur les espaces ultramétriques. Nous montrons dans un premier temps que lorsque l’espace ultramétrique est propre, son espace libre a la propriété d’approximation métrique et est isomorphe à l1, de plus il admet un prédualisomorphe à c0. Enfin, en collaboration avec P. Kaufmann et A. Prochàzka, nous montrons que l’espace libre sur un espace ultramétrique n’est jamais isométrique à un espace l1 et nous généralisons ce résultat à certains sous-ensembles des arbres réels séparables. / Godefroy and Ozawa have proved that there exists a compact space with a free space failing the approximation property. Then it is natural to ask what are the metric spaces whose freespace has the bounded approximation property. Grothendieck has proved that a separable Banach space with the approximation property has the metric approximation property. This result justifies why it is interesting to know whether a free space is a dual space. The first chapter is dedicated to duality. First we introduce a result to prove that a Banach space is a dual space, under some conditions. Then we explain how to use it in the context offree spaces and finally we apply it to countable or ultrametric proper metric spaces.In the second chapter, we study the metric approximation property of free spaces overcountable proper metric spaces.In the third chapter, ultrametric spaces are investigated. We prove first that the free spaceover a proper ultrametric space has the metric approximation property, is isomorphic to l1 andadmits a predual isomorphic to c0. Finally, in collaboration with P. Kaufmann et A. Proch`azka,we prove that the free space over a ultrametric space is never isometric to l1 and we generalizethis result to some subsets of separable R-trees.

This paper deals with the propagation of waves. Here is the wavelength distribution according to the wavelength. It focuses on the UHF and SHF band in which IEEE802.11n operates. Contains model breakdown by cell type. Describes which propagation methods are dominant in the cell type. Several propagation patterns are presented, which are then modeled in Matlab environment.The models are then compared to experimental measurements.

[ES] Los espacios libres Lipschitz F(M) son linearizaciones canónicas de espacios métricos M cualesquiera. Más concretamente, F(M) es el único espacio de Banach que contiene una copia isométrica de M que es linearmente densa, y tal que toda aplicación Lipschitz de M en cualquier espacio de Banach X puede extenderse a un operador linear continuo de F(M) en X. Estos espacios suponen una herramienta muy potente para el estudio de la geometría no lineal de espacios de Banach, al permitir la aplicación de las técnicas lineales clásicas, bien conocidas, a problemas no lineales. Pero este esfuerzo sólo merece la pena si se dispone de un conocimiento lo bastante detallado de la estructura de F(M). El estudio sistemático de los espacios libres Lipschitz es bastante reciente y, por ello, dicho conocimiento es todavía más bien limitado. Esta tesis se enmarca en el programa general de estudio de la estructura espacios libres Lipschitz genéricos. Empezamos nuestro estudio desarrollando algunas herramientas básicas para la teoría general de espacios libres Lipschitz. Primero definimos operadores de ponderación en espacios Lipschitz y los usamos para demostrar la conjetura de Weaver de que todos los funcionales normales del bidual F(M)** son débil* continuos. A continuación demostramos el teorema de la intersección, que en esencia dice que la intersección de espacios libres Lipschitz es de nuevo un espacio libre Lipschitz. Este resultado nos permite desarrollar el concepto de soporte de un elemento de F(M), análogo al de soporte de una medida. Además, extendemos el uso de estas herramientas al bidual F(M) y las usamos para establecer una descomposición del bidual en espacios de funcionales que están "concentrados en el infinito" y "separados del infinito", respectivamente. Con estas herramientas en nuestro poder, emprendemos el estudio de dos aspectos concretos de los espacios libres Lipschitz. En primer lugar analizamos la relación entre F(M) y los espacios de medidas sobre M. En particular, obtenemos caracterizaciones de los elementos de F(M) que pueden representarse como la integración con respecto a una medida de Borel (no necesariamente finita) sobre M y viceversa, y probamos que el soporte coincide con el de la medida asociada. También identificamos los espacios métricos M en los cuales todo elemento de F(M) puede ser representado como una medida de Borel. Este análisis se generaliza al bidual F(M)**, utilizando en este caso medidas sobre la compactificación uniforme de M y llegando a resultados similares. Obtenemos también algunas consecuencias para los elementos de F(M) y F(M)** que pueden expresarse como diferencia de dos elementos positivos, como la existencia de un análogo de la descomposición de Jordan para medidas. En segundo lugar, estudiamos la estructura extremal de la bola unidad de F(M) y hacemos algunas contribuciones al programa general consistente en encontrar caracterizaciones puramente geométricas de todos sus elementos extremales. Concretamente, caracterizamos los puntos extremos preservados de la bola, así como aquellos puntos extremos y expuestos que tienen soporte finito. Además damos una descripción completa de la estructura extremal de la parte positiva de la bola unidad. La teoría de los soportes en F(M) desarrollada anteriormente juega un papel crucial en las demostraciones de estos resultados. / [CA] Els espais lliures Lipschitz F(M) són linearitzacions canòniques d'espais mètrics M qualssevol. Més concretament, F(M) és l'únic espai de Banach que conté una còpia isomètrica de M que és linealment densa, i tal que tota aplicació Lipschitz de M en qualsevol espai de Banach X pot ser estesa a un operador lineal continu de F(M) en X. Aquests espais són una eina molt potent per a l'estudi de la geometria no lineal d'espais de Banach, ja que permeten l'aplicació de les tècniques lineals clàssiques, ben conegudes, a problemes no lineals. Però aquest esforç nomes val la pena si es disposa d'un coneixement bastant detallat de l'estructura de F(M). L'estudi sistemàtic dels espais lliures Lipschitz és bastant recent i, per això, aquest coneixement és encara prou limitat. Aquesta tesi s'emmarca en el programa general d'estudi de l'estructura dels espais lliures Lipschitz genèrics. Comencem el nostre estudi desenvolupant algunes eines bàsiques per a la teoria general d'espais lliures Lipschitz. Primer definim operadors de ponderació en espais Lipschitz i els fem servir per demostrar la conjectura de Weaver que tots els funcionals normals del bidual F(M)** son feble* continus. A continuació demostrem el teorema de la intersecció, que en essència diu que la intersecció d'espais lliures Lipschitz és de nou un espai lliure Lipschitz. Aquest resultat ens permet desenvolupar el concepte de suport d'un element de F(M), anàleg al de suport d'una mesura. A més, estenem l'ús d'aquestes eines al bidual F(M)** i les fem servir per establir una descomposició del bidual en espais de funcionals que estan "concentrats a l'infinit" i "separats de l'infinit", respectivament. Amb aquestes eines al nostre abast, emprenem l'estudi de dos aspectes concrets dels espais lliures Lipschitz. En primer lloc, analitzem la relació entre F(M) i els espais de mesures sobre M. En particular, obtenim caracteritzacions dels elements de F(M) que poden representar-se com la integració respecte a una mesura de Borel (no necessàriament finita) sobre M i viceversa, i provem que el suport coincideix amb el de la mesura associada. També identifiquem els espais mètrics M on tot element de F(M) pot ser representat com una mesura de Borel. Aquesta anàlisi es generalitza al bidual F(M)**, utilitzant en aquest cas mesures sobre la compactificació uniforme de M i arribant a resultats similars. També obtenim algunes conseqüències per als elements de F(M) i F(M)** que poden expressar-se com a diferència de dos elements positius, com ara l'existència d'un anàleg de la descomposició de Jordan per a mesures. En segon lloc, estudiem l'estructura extremal de la bola unitat de F(M) i fem algunes contribucions al programa general consistent en trobar caracteritzacions purament geomètriques de tots els seus elements extremals. Concretament, caracteritzem els punts extrems preservats de la bola, així com aquells punts extrems i exposats que tenen suport finit. A més fem una descripció completa de l'estructura extremal de la part positiva de la bola unitat. La teoria dels suports en F(M) desenvolupada anteriorment juga un paper crucial en les demostracions d'aquests resultats. / [EN] Lipschitz-free spaces F(M) are canonical linearizations of arbitrary complete metric spaces M. More specifically, F(M) is the unique Banach space that contains an isometric copy of M that is linearly dense, and such that any Lipschitz mapping from M into some Banach space X extends to a bounded linear operator from F(M) into X. Those spaces are a very powerful tool for studies of the nonlinear geometry of Banach spaces, as they allow the application of well-known classical linear techniques to nonlinear problems. But this effort is only worthwhile if we have sufficient knowledge about the structure of F(M). The systematic study of Lipschitz-free spaces is rather recent and so the current understanding of their structure is still quite limited. This thesis is framed within the general program of studying the structure of general Lipschitz-free spaces. We start our study by developing some basic tools for the general theory of Lipschitz-free spaces. First we introduce weighting operators and use them to solve Weaver's conjecture that all normal functionals in the bidual F(M)** are weak* continuous. Next we prove the intersection theorem, which essentially says that the intersection of Lipschitz-free spaces is again a Lipschitz-free space. That result allows us to develop the concept of support of an element of F(M), analogous to the support of a measure. Furthermore, we extend the use of these tools to the bidual F(M)** and apply them to establish a decomposition of the bidual into spaces of functionals that are "concentrated at infinity" and "separated from infinity", respectively. With these tools at our disposal, we undertake the study of two particular aspects of Lipschitz-free spaces. First we analyze the relationship between F(M) and spaces of measures on M. In particular, we obtain characterizations of those elements of F(M) that can be represented as integration against a (not necessarily finite) Borel measure on M and vice versa, and we show that their supports agree. We also identify those metric spaces such that every element of F(M) can be represented by a Borel measure. This analysis is generalized to the bidual F(M)**, using measures on the uniform compactification of M in that case and obtaining similar results. We also derive some consequences for those elements of F(M) and F(M)** that can be expressed as the difference between two positive elements, such as the existence of an analog of the Jordan decomposition for measures. Secondly, we study the extremal structure of the unit ball of F(M) and provide some contributions to the general program of finding purely geometric characterizations of all of its extremal elements. Namely, we characterize all of its preserved extreme points, and its extreme and exposed points of finite support. We also give a full description of the extremal structure of the positive unit ball. The theory of supports developed previously plays a crucial role in the proofs of these results / The author would like to thank Marek Cúth, Michal Doucha, Antonio José Guirao, Gilles Lancien and Eva Pernecká for their careful reading and correction of this document or parts of it. Some activities related to this thesis were partially supported by the Spanish Ministry of Economy, Industry and Competitiveness under Grant MTM2017-83262-C2-2-P, and by a travel grant of the Institute of Mathematics (IEMath-GR) of the University of Granada. Part of this research was conducted during visits to the Czech Technical University in Prague in 2018 and 2020, the Laboratoire de Mathématiques de Besançon in 2019, and the University of Granada in 2020. The author wishes to express his gratitude for the hospitality and the excellent working conditions during his visits. / Aliaga Varea, RJ. (2020). Geometry and structure of Lipschitz-free spaces and their biduals [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/159256 / TESIS

The main aim of this thesis is the design of an optical wireless link that is transmitted in free space, in the atmosphere. The thesis describes the composition of heads of the atmospheric optical link. One part of this work focuses on the issue of the spread of optical beam in the atmosphere. The facts which have a major impact on the transmission of optical radiation in free space are pointed out here as well. In this work phenomena of absorption, refraction of light, turbulence and dispersion are discussed. Wavelengths spread in the atmosphere with different decline and therefore this thesis provides an analysis of the use of wavelengths between 750 and 1600 nm depending on the meteorological visibility. It describes the basis of the design of AOS through stationary model using power balance equation. It depicts the description of the statistical model, which makes possible to determine the availability on the basis of probability. Current possibilities of AOS are in general described in this work. The practical part of the work is focused on the design of simulation model of transmitter and receiver AOS in the program Pspice. The receiver and transmitter are designed to replace transiver in the media converter. The receiver plays a key role, and therefore big part of the thesis is given to it. Receiver model is composed of a photodiode and of an transimpedance amplifier. The receiver circuit has been tested. The model of transmitter shows the principle of modulating of current, which flows in laser diode. This work does not carried the model of atmosphere, which would serve as a link between the receiver and the transmitter. The circuit of the receiver is subjected to the noise analysis. Parameter NEP and SNR is designed. Link budget is calculated for models of the receivers and the transmitters. The maximum distance of heads is set based on the requirements for a BER error rate which combine this condition. The design of the practical implementation results from the models of transmitters and receivers. Printed circuit boards are designed in EAGLE. Within the frame of this thesis no curcuit diagram is carried out.

The diploma thesis deals with description and design of a low-cost free-space optical (FSO) link. First, general FSO theory is discussed including their common parameters, properties and topologies. Further, optical signal sources and detectors are proposed. Finally, the selected implementation is described including its design and realization. The proposed FSO consists of two identical segments (modules) to form a full-duplex link. The FSO utilizes LED as a light source, maximum speed data rate is 100 Mb/s with 100Base-TX interface.