The thesis deals with molecular dynamic simulation of the influence of water on the deformation of hydrogels. Hydrogels are model materials formed from macromolecular networks solvated with water. It was found that water can form bridges between macromolecules that take the form of temporary ionic crosslinks. These bridges affect the behavior of the network during deformation. Water bridges are water molecules that have a limited radius of motion in the space between two macromolecules. The concentration of the water bridges was regulated by a partial charge on the macromolecular chain in the organic network. Bridges are a type of interaction that is relatively strong but significantly delocalized. It is not possible to dissociate the water bridge, after dissociation it will be re-created in another place in a short time. The influence of water bridges was compared with other types of network crosslinks, especially covalent and physical bonds. Covalent crosslinks are modeled as a simple binding interaction between two macromolecules. They are undissociable and are local throughout the simulation. Physical bonds are modeled as micelles, where hydrophobic groups form the core and hydrophilic groups form the micelle shell. Physical bonds have the nature of dissociable bonds that are local. Different types of crosslinks have different effects on deformation properties. The deformation of a network containing a combination of two types of crosslinks was simulated: (i) physically-covalent, (ii) ionically-covalent, and (iii) physically-ionic networks and (iv) ternary physically-covalent-ion networks. For individual and combined networks, the behavior depending on simple networks was verified. The number of water bridges was fundamentally affected by the primary structure of the chains. When the PEG chain was replaced with hydrophobic polyoxymethylene (POM) or polyoxytrimethylene (POTM), their solvation and mechanical behavior deteriorated.

The presented master thesis is focused on the stock markets returns analysis using a new type of neural network. First chapter of the thesis describes the underlying theory of the financial time series prediction, Efficient Market Hypothesis and conventional forecasting models. Following part illustrates biological framework, basic principles, functioning of neural networks, their architecture and several well-known learning algorithms such as Gradient descent, Levenberg-Marquardt algorithm or Conjugate gradient. It also mentions certain disadvantages which influence the performance and effectiveness of neural networks. Third chapter is devoted to two applied metaheuristic techniques, i.e. genetic algorithms and simulated annealing that were integrated into neural networks framework to eliminate above mentioned drawbacks. Next chapter describes details of presented hybrid network, whereas the last section is aimed at evaluation of overall results of all models. It shows that on the examined sample hybrid network clearly outperformed standard techniques as well as ordinary neural networks and in most cases achieved the least mean squared error among all explored methods. Keywords: stock returns analysis, neural networks, genetic algorithms, simulated annealing, hybrid networks JEL classification:...

Rhythmic neural activity is thought to underlie many high-level functions of the nervous system. Our goals are to understand rhythmic activity starting with small networks, using theoretical and experimental tools. Phase resetting theory describes essential properties that cause and destroy rhythms. We validate and extend one branch of this theory, testing it in bursting neurons coupled by excitation and then extending the theory to account for temporal variability found in our experimental data. We show that the theory makes good predictions of rhythmic activity in heterogeneous networks. We also note differences in mathematical structure between inhibition- and excitation-coupling that cause them to behave differently in noisy contexts and may explain why all central pattern generators (CPGs) found in nature are dominated by inhibition. Our extension of the theory gives a method that is useful to compare experimental and model data and shows that noise may either create or destroy a rhythm. Finally, we described the cellular mechanisms in Aplysia that switch the feeding CPG from arrhythmic to rhythmic behavior in response to reward stimuli. Previous studies showed that a Dopamine reward signal is correlated to changes in electrical coupling and excitability in several important neurons in the CPG. Using the dynamic clamp and an in vitro analog of the full behavioral system, we were able to determine that electrical coupling alone controls rhythmicity, while excitability independently controls the rate of activity. These results beg for further study, including new theory to explain them fully.

Les réseaux logiciels (Software Defined Network - SDN) permettent la programmation du réseau et facilitent sa configuration. Bien qu'SDN améliore les performances, il reste confronté à de multiples défis. Dans cette thèse, nous avons développé des solutions qui constituent un premier pas vers les réseaux SDN de prochaine génération. D’abord, nous présentons MINNIE qui permet la scalabilité des commutateurs SDN, qui ne supportent que quelques milliers de règles dans leur coûteuse mémoire TCAM. MINNIE comprime dynamiquement les règles de routage installées dans la TCAM, augmentant ainsi le nombre de règles pouvant être installées. Ensuite, nous abordons le problème de la dégradation de performance des flux courts avec un prototype d’ordonnancement qui exploite les statistiques des commutateurs pour diminuer leur délai de bout-en-bout. Puis, nous visons à diminuer l’intervalle de protection de 50ms qui n’est plus adapté aux applications modernes et réduit leur qualité d’expérience. Notre solution PRoPHYS s’appuie sur les statistiques des commutateurs dans les réseaux hybrides pour découvrir les pannes de liens plus vite que les solutions existantes. Enfin, nous abordons le problème de l’efficacité énergétique qui souvent mène à une dégradation de performance. Nous présentons SENAtoR, qui exploite les nœuds SDN en réseaux hybrides pour éteindre les nœuds réseau sans entraver la performance. Également, nous présentons SEaMLESS qui convertit le service fourni par une machine virtuelle inactive en une fonction de réseaux virtuelle pour permettre à l’administrateur d’utiliser les ressources bloquées tout en maintenant la disponibilité du service. / Software Defined Networking (SDN) was created to provide network programmability and ease complex configuration. Though SDN enhances network performance, it still faces multiple limitations. In this thesis, we build solutions that form a first step towards creating next-generation SDN based networks. In the first part, we present MINNIE to scale the number of rules of SDN switches far beyond the few thousands rules commonly available in TCAM memory, which permits to handle typical data center traffic at very fine grain. To do so MINNIE dynamically compresses the routing rules installed in the TCAM, increasing the number of rules that can be installed. In the second part, we tackle the degraded performance of short flows and present a coarse grained scheduling prototype that leverages SDN switch statistics to decrease their end-to-end delay. Then, we aim at decreasing the 50ms failure protection interval which is not adapted to current broadband speeds and can lead to degraded Quality of Experience. Our solution PRoPHYS leverages the switch statistics in hybrid networks to anticipate link failures by drastically decreasing the number of packets lost. Finally, we tackle the greening problem where often energy efficiency comes at the cost of performance degradation. We present SENAtoR, our solution that leverages SDN nodes in hybrid networks to turn off network devices without hindering the network performance. Finally, we present SEaMLESS that converts idle virtual machines into virtual network functions (VNF) to enable the administrator to further consolidate the data center by turning off more physical servers and reuse resources (e.g. RAM) that are otherwise monopolized.

The industrial needs in the production of goods and control of processes within the factory keep leapfrogging daily by the necessities to fulfil the needs of the ever-growing population. In recent times, the industries are looking towards Industry 4.0 to improve their overall productivity and scalability. One of the significant aspects that are required to meet the requirements of Industry 4.0 is communication networks among industrial applications. Nowadays, industries from the cross markets are looking to replace their existing wired networks with wireless networks, which indeed brings many use-cases and a lot of new business models into existence. To make all these options possible, wireless networks need to meet the stringent requirements of these industrial applications in the form of reliability, latency, and service availability. This thesis focuses on a systematic methodology to integrate wireless networks like 5G, Wi-Fi 6, etc., into real-life automation devices. It also describes a methodology to evaluate their communication and control performance by varying control parameters like topology, cycle time, and type of networks. It also devises some techniques and methods that can improve the overall performance, i.e., both control and communication performance of the control applications. The method used to implement this work is a case study. This work integrates and tests the industrial applications in a real-life scenario. It is the best effort to bring a unique perspective of communication engineers and control engineers together regarding the performance of the industrial applications. This work tries to verify the suitability of the wireless in mission-critical control application scenarios with respect to their communication and control performance. Software for data analysis and visualization and its methodology for analyzing the traffic flow of the control applications via different wireless networks is demonstrated by varying different control parameters. It is shown that it is challenging for 5G to support the shorter cycle time values, and performance will get better and more stable with the increase in the cycle time of the control application. It is also found that the 1-Hop wireless topologies have a comparatively better control performance than 2-Hop wireless topologies. In the end, it is found that the communication and control performance of the motion control application can be improved by using the hybrid topology, which is a mixture of 5G and Wi-Fi 6, by modifying some key aspects. The thesis work helps to introduce a novel systematic methodology for measuring and analyzing the communication and control applications via different wireless networks. It also gives a better idea for the control engineers in the industry about which cycle times the different wireless networks and their topologies support when integrated with industrial automation devices. It also describes which wireless networks support industrial applications better. It ends with a novel methodology that could improve the performance of the mission-critical motion applications by using existing wireless technologies.

[ES] El estándar de quinta generación (5G) es la clave potencial para satisfacer el aumento exponencial en la demanda de nuevas aplicaciones, servicios y usuarios. La tecnología 5G ofrecerá una latencia extremadamente baja de 1 ms, una velocidad máxima de datos de 10 Gbit/s, una alta densidad de conexión de hasta 106 dispositivos/km2 y permitirá una alta movilidad de los dispositivos de hasta 500 km/h. En esta Tesis se proponen varias soluciones basadas en tecnologías habilitadoras para el despliegue de redes 5G. La arquitectura de la red de acceso de radio en la nube (C-RAN) se emplea junto con las técnicas de Fotónica de Microondas como una solución prometedora para generar y transmitir señales de ondas milimétricas (mmW) en la próxima generación de comunicaciones móviles. La tecnología radio sobre fibra (RoF) ha demostrado ser una buena opción para enfrentarse al desafío de la distribución inalámbrica mmW debido a la gran distancia de transmisión, el gran ancho de banda y la inmunidad a las interferencias electromagnéticas, entre algunas de las principales ventajas. Además, esta tecnología se puede ampliar con comunicaciones ópticas de espacio libre (FSO) en sistemas de radio sobre FSO (RoFSO) en las redes inalámbricas. En esta Tesis, las señales mmW se generan fotónicamente mediante modulación externa de doble banda lateral con supresión de portadora (CS-DSB) y se distribuyen a través de enlaces fronthaul híbridos RoF/FSO. Además, la generación múltiple de señales permite la distribución reconfigurable en canales multiplexados por división de longitud de onda (WDM) desde una oficina central hasta las estaciones base, y se ha evaluado el impacto de las turbulencias producidas en los canales FSO sobre las señales mmW generadas fotónicamente en términos de fluctuaciones de potencia y ruido de fase de la señal. Se propone la técnica de modulación directa de un láser (DML) como solución principal para la transmisión de datos a través de enlaces ópticos híbridos que emplean un esquema de multiplicación de frecuencias ópticas, es decir, CS-DSB, para la generación de señales de mmW. En concreto, se evalúan teórica y experimentalmente los esquemas de generación fotónica local y remoto de señales mmW y se comparan para su implementación práctica en la red frontal de la C-RAN y, además, se estudia experimentalmente el impacto de la distorsión armónica y de la intermodulación en la transmisión de datos. Igualmente, con el fin de obtener la capacidad que ofrece el DML en términos de ancho de banda, también se presenta una evaluación teórica y experimental del efecto de la dispersión de la fibra y el chirp sobre diferentes anchos de banda de señales de M-modulación de amplitud en cuadratura (QAM). No obstante, la Tesis también incluye otro enfoque para la transmisión de datos basado en el uso de otro modulador externo. En este caso, la demostración experimental de la generación de señales ópticas empleando CS-DSB y la transmisión de señales a través de fibra híbrida y red frontal FSO se completa con un enlace de antena que permite transmitir señales 5G 64/256-QAM. La investigación realizada con los sistemas CS-DSB y DSB también permiten comparar la robustez frente al desvanecimiento inducido por la dispersión cromática de la fibra. Además, se ha realizado una evaluación experimental impacto las turbulencias producidas en los canales FSO sobre las señales mmW generadas fotónicamente con diferentes distribuciones térmicas y se ha cuantificado la degradación de la señal de datos de acuerdo con las condiciones de la turbulencia. Como demostradores finales, esta Tesis incluye un sistema de transmisión full-dúplex que emplea señales 5G en enlace descendente (DL) a 39 GHz y en enlace ascendente (UL) a 37 GHz; y la transmisión de señales OFDM LTE de 60 GHz (DL) y 25 GHz (UL) sobre una infraestructura heterogénea de frontal óptico que consiste en fibra óptica de 10 km, un canal FSO de 100 m y un enlace de radio inalámbrico de 2 m. / [CA] L'estàndard de quinta generació (5G) és la clau potencial per a satisfer l'augment exponencial en la demanda de noves aplicacions, serveis i usuaris. La tecnologia 5G oferirà una latència extremadament baixa d'1 ms, una velocitat màxima de dades de 10 Gbit/s, una alta densitat de connexió de fins a 106 dispositius/km2 i permetrà una alta mobilitat dels dispositius de fins a 500 km/h. En aquesta tesi es proposen diverses solucions basades en tecnologies habilitadores per al desplegament de xarxes 5G. L'arquitectura de la xarxa d'accés de ràdio en el núvol (CRAN) s'empra junt amb les tècniques de Fotònica de Microones com una solució prometedora per a generar i transmetre senyals d'ones mil·limètriques (mmW) en la pròxima generació de comunicacions mòbils. La tecnologia ràdio sobre fibra ( RoF) ha demostrat ser una bona opció per a enfrontar-se al desafiament de la distribució sense fil mmW a causa de la gran distància de transmissió, el gran ample de banda i la immunitat a les interferències electromagnètiques, entre alguns dels principals avantatges. A més, aquesta tecnologia es pot ampliar amb comunicacions òptiques d'espai lliure (FSO) en sistemes de ràdio sobre FSO (RoFSO) en les xarxes sense fil. En aquesta Tesi, els senyals mmW es generen fotònicament per mitjà de modulació externa de doble banda lateral amb supressió de portadora (CS-DSB) i es distribueixen a través d'enllaços frontals híbrids RoF/FSO.. A més, la generació múltiple de senyals permet la distribució reconfigurable en canals multiplexats per divisió de longitud d'ona ( WDM) des d'una oficina central fins a les estacions base, i s'ha avaluat l'impacte de les turbulències produïdes en els canals FSO sobre els senyals mmW generades fotònicament en termes de fluctuacions de potència i soroll de fase del senyal. Aquest treball proposa la tècnica de modulació directa d'un làser (DML) com solució principal per a la transmissió de dades a través d'enllaços òptics híbrids que fan servir un esquema de multiplicació de freqüències òptiques, és a dir, CS-DSB, per a la generació de senyals de mmW. En concret, s'avalua teòric i experimentalment els esquemes de generació fotònica local i remota de senyals mmW i es comparen per a la seua implementació pràctica a la xarxa frontal de la C-RAN i a més, s'estudia experimentalment l'impacte de la distorsió harmònica i de la intermodulació en la transmissió de dades. Igualment, amb el fi d'obtindre la capacitat que ofereix el DML en termes d'amplada de banda, també es presenta una avaluació teòrica i experimental de l'efecte de la dispersió de la fibra i el chirp sobre diferents amples de banda de senyals de M-modulació d'amplitud en quadratura (QAM). No obstant això, la Tesis també inclou altre enfocament per a la transmissió de dades basat amb l¿ús d'altre modulador extern. En aquest cas, la demostració experimental de la generació de senyals òptics emprant CS-DSB i la transmissió de senyals a través de fibra híbrida i xarxa frontal FSO es completa com un enllaç d'antena que permet transmetre senyals 5G 64/256-QAM. La investigació realitzada amb els sistemes CS-DSB i DSB també permet comparar la seua robustesa davant l¿esvaïment induït per la dispersió cromàtica. A més, s'ha avaluat experimentalment l'impacte de les turbulències produïdes en els canals FSO sobre els senyals mmW generades fotònicament amb diferents distribucions tèrmiques i s'ha quantificat la degradació del senyal de dades d'acord amb les condicions de la turbulència. Com a demostradors finals, aquesta Tesi inclou un sistema de transmissió full-dúplex que empra senyals 5G en enllaç descendent (DL) a 39 GHz i en enllaç ascendent (UL) a 37 GHz; i la transmissió de senyals OFDM LTE de 60 GHz (DL) i 25 GHz (UL) sobre una infraestructura heterogènia de frontal òptic que consisteix en fibra òptica de 10 km, un canal FSO de 100 m i un enllaç de ràdio sense fil de 2 m. / [EN] The fifth generation (5G) standard is the potential key to meet the exponentially increasing demand of the emerging applications, services and mobile end users. 5G technology will offer an extremely low latency of 1 ms, peak data rate of 10 Gbit/s, high contention density up to 106 devices/km2 and enable high mobility up to 500 km/h. This Thesis proposes several solutions based on enabling technologies for deploying 5G networks. Cloud-radio access network (C-RAN) architecture is employed in conjunction with microwave photonics techniques as a promising solution to generate and transmit millimeter wave (mmW) signals in the next generation of mobile communications. Radio over fiber (RoF) has been demonstrated as a good option to face the challenge of mmW wireless distribution, due to long transmission distance, large bandwidth and immunity to electromagnetic interference, as some of the main advantages. Moreover, this technology can be extended with free-space optical (FSO) communications in Radio over FSO systems (RoFSO) as wireless networks. In this Thesis, mmW signals are photonically generated by carrier suppressed double sideband (CS-DSB) external modulation and distributed over hybrid RoF/FSO fronthaul links. Moreover, multiple generated signals allow reconfigurable distribution in wavelength-division multiplexed (WDM) channels from a central office to the base stations, and the impact of turbulent FSO channels on photonically generated mmW signals has been evaluated in terms of power signal fluctuations and phase noise. A directly modulated laser (DML) is proposed as a major solution for signal transmission over hybrid optical links employing optical frequency multiplication scheme, i.e. CS-DSB, for mmW signal generation. Moreover, local and remote photonic mmW signal generation schemes are theoretically and experimentally evaluated and compared for practical deployment in C-RAN fronthaul network while the impact of harmonic and intermodulation distortion on data transmission is also experimentally studied. Furthermore, for the sake of obtaining the DML usability in terms of bandwidth, theoretical and experimental evaluation of the effect of fiber dispersion and chirp over different M-quadrature amplitude modulation (QAM) signals bandwidth is also presented. Another data transmission approach based on the cascade of two external modulators is also employed in the Thesis. In this case, the experimental demonstration of optical signal generation employing CS-DSB and signal transmission over hybrid fiber and FSO fronthaul network is completed with a seamless antenna link leading to successful transmission of 64/256-QAM 5G signals. The CS-DSB and DSB schemes are also investigated for the sake of comparison in terms of robustness against fiber chromatic dispersion-induced fading. Furthermore, experimental evaluation of the impact of turbulent FSO links on photonically generated mmW signals with different thermal distributions has been performed and data signal degradation has been quantified according to the turbulence conditions. As final demonstrators, the Thesis includes a full-duplex transmission system employing 39 GHz downlink (DL) and 37 GHz uplink (UL) 5G signals over hybrid links; and 60 GHz (DL) and 25 GHz (UL) OFDM LTE signal transmission over an heterogeneous optical fronthaul infrastructure consisting of 10 km optical fiber, 100 m FSO channel and 2 m wireless radio link. / I would like to acknowledge the financial support given by Research Excellence Award Programme GVA PROMETEO 2017/103 Future Microwave Photonics and European Network for High Performance Integrated Microwave Photonics (EUIMWP) CA16220. / Vallejo Castro, L. (2022). Photonic Millimeter Wave Signal Generation and Transmission Over Hybrid Links in 5G Communication Networks [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/190253