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Passive radar is a technology for detection of targets using echoes of existing radio transmitter, such as FM-radio. Since only receivers are needed for operation, a passive radar system has the possibility of being implemented using low-cost hardware. Using lower cost implementations to cover blind-spots of other, more sophisticated systems, could be a viable solution for full radar coverage. To achieve this, an understanding of the effects such low-cost systems have on the performance of a radar is needed.  A prominent problem for passive radar is that the interference caused by the direct signal from the transmitter used and reflections from uninteresting terrain, called clutter, can drown out the echoes from targets. This thesis compares the direct signal interference (DSI) suppression algorithms: ECA, ECA-S, ECA-B, NLMS and FBNLMS when run on data from a low-cost receiver called KerberosSDR. It is found that the low ADC resolution of 8 bits is a limiting factor for KerberosSDR. Random noise in the receiver can also limit the performance. None of the tested algorithms are any more or less affected by the ADC resolution or the noise. The first difference appears when comparing the execution times, where FBNLMS is 10–20 times faster than the other algorithms. However, the slower rate of convergence for FBNLMS and NLMS causes them to lose performance in environments where the DSI and clutter are considerably stronger than the target echoes. The algorithms FBNLMS and NLMS also lose performance due to their inability to model frequency shifted echoes as unwanted. The main disadvantages of ECA, ECA-B and ECA-S are their long execution time. It is concluded that FBNLMS would be the best candidate in most cases for low-cost hardware, as it allows execution on slower hardware and the main disadvantages not being too prominent in the use case of covering blind-spots of other systems.

Software-Defined Wide Area Networks is a technology that has received a lot of attention in recent years. The technology enables direct Internet access without having to direct traffic through a data center. It also enables the use of less expensive Internet connections to build the Wide-Area Network, expensive Multiprotocol LabelSwitchingconnectionsarenolongernecessary. This results in greater responsibility for enterprises when it comes to ensuring performance within the network, where the previous dedicated links with a guaranteed performance by Internet Service Provider have been replaced with unpredictable best-effort connections. The project targets the challenges Software-Defined Wide Area Networks introduces in terms of monitoring, by examining the required network transparency between Wide-Area Network edges. A selection of Network Management Systems was evaluated with the requirements specification as a basis. The results show that more diligent monitoring at the edges is needed. Visibility into the underlay network, providing transportation, has to be available. Where the enterprises need to be able to examine path-selection of traffic per application. To ensure that the root of problems can be located in case of performance issues. This was not obtained by the evaluated Network Management Systems. Moreover, it turned out that there was no common standard available for monitoring the technology at the time of the project. The lack of knowledge in the field aimed to decrease with the degree project and the result is of greatest interest to companies that have made the transition to Software-Defined Wide Area Networks or are about to do so. / Software-Defined Wide Area Networks är en teknik som har fått mycket uppmärksamhet de senaste åren. Tekniken möjliggör direkt internetåtkomst utan att behöva dirigera trafik genom datacentret. Det möjliggör också användningavbilligareinternetanslutningar för att bygga Wide-AreaNetwork, dyra Multiprotocol Label Switching anslutningar är inte längre nödvändiga. Detta resulterar i ett större ansvar för företag när det gäller att säkerställa prestanda inom nätverket, där de tidigare dedikerade länkarna med garanterad prestanda av internetleverantörer har ersatts med oförutsägbara anslutningar som skickar trafik efter bästa förmåga. Examensarbetet riktar sig mot de utmaningar som Software-Defined Wide Area Networks innebär när det gäller övervakning, genom att undersöka den nödvändiga nätverkstransparensen mellan Wide-Area Network kanterna. Ett urval av nätverkshanteringssystem utvärderades med en definierad kravspecifikation som grund. Resultaten visar att det behövs mer noggrann övervakning i Wide-Area Network kanterna. Insyn i transportlagret måste vara tillgänglig och företagen behöver kunna granska vägval av trafik per applikation, för att säkerställa att ursprungsfel går att lokaliseras i händelse av prestandaproblem. Detta erhölls inte av de utvärderade nätverkshanteringssystemen. Det visade sig dessutom att det inte fanns någon gemensam standard tillgänglig för övervakning av tekniken vid tidpunkten för examensarbetet. Examensarbetet syftar till att minska kunskapsbristen inom området och resultatet är av störst intresse för företag som gjort övergången till Software-Defined Wide Area Networks eller är på väg att göra det.

The subject of this thesis is application of Notional Defined Contribution system in Czech Republic. In this pension system everybody has his own individual pension account on which he or she saves money. Interest is accredited to this account. When this person retires, the pension is calculated based on pension account balance. Contributions do not really stay in pension system, but they are paid to current pensioners (resemblance to PAYG system). In first chapter I deal with pension systems in general, in second chapter I deal with theoretical NDC system. In third chapter I analyze practical application of NDC system in Sweden. Fourth part of this thesis analyses the possibility of introducing NDC pension system in Czech republic.

Software Defined Networking (SDN) provides centralized control by separating the control plane from the data plane on network devices. Subareas of networking such as Quality of Service (QoS) can greatly benefit from this separation as QoS policies can be provided globally for the network. One way of providing QoS is to reserve and monitor network resources to guarantee a specific data rate for a requested transmission end-to-end. The presented thesis looks into possible ways of controlling the wireless medium using SDN to provide QoS. A method for providing QoS in a multihop SDN network supporting wired and wireless communication was implemented. The method was evaluated using network performance metrics such as throughput and packet jitter. The results of the experiments showed that the implemented method could limit bandwidth utilization and prioritize bandwidth usage for higher priority nodes. The performance of the network was concluded to have severe issues with dropped packets and irregular packet jitter spikes.

Les travaux de cette thèse s'inscrivent dans le contexte général des réseaux logiciels, dits "Software-Defined Networking" (SDN). Ce paradigme récent est l'une des initiatives les plus notables pour rendre les réseaux actuels programmables ou, en d'autres termes, plus simple à configurer, à tester, à corriger et à faire évoluer. Dans un écosystème SDN, l'interface nord (Northbound API) est utilisée par l'administrateur réseaux pour définir ses politiques et programmer le plan de contrôle, elle représente donc un enjeu majeur. Idéalement, cette interface nord devrait permettre aux administrateurs de décrire, le plus simplement possible, des services réseaux et leurs interactions, plutôt que de spécifier comment et sur quels équipements physiques ils doivent être déployés. Des travaux existants montrent que cela peut être notamment réalisé grâce à des solutions de virtualisation de réseaux et des langages de programmation dédiés de haut niveau. L'objectif de ce travail de thèse est de proposer une nouvelle interface nord qui, d'une part, exploiterait la virtualisation de réseau et, d'autre part, exposerait ses services sous la forme d'un langage de programmation dédié. Actuellement, plusieurs langages intégrant des solutions de virtualisation de réseau existent. Néanmoins, nous pensons que les modèles d'abstraction qu'ils utilisent pour construire des réseaux virtuels restent inappropriés pour assurer des critères de simplicité, modularité et flexibilité des topologies virtuelles et des programmes de contrôle. Dans ce contexte, nous proposons un nouveau langage de contrôle de réseaux nommé AirNet. Ce dernier intègre un modèle d'abstraction dont la principale caractéristique est d'offrir une séparation nette entre les équipements de bordure (Edge) et de cœur de réseau (Fabric). Cette idée est bien connue et acceptée dans le domaine des architectures réseaux. L'originalité de notre contribution étant de faire remonter ce concept au niveau du plan de contrôle virtuel et non de le restreindre au seul plan physique. Ainsi, des frontières logiques entre les différents types de politiques existeront (fonctions de contrôle et de données vs. fonctions de transport), garantissant ainsi la modularité et la réutilisabilité de tout ou partie du programme de contrôle. De plus, dans l'approche proposée, la définition du réseau virtuel et des politiques peut être totalement dissociée de l'infrastructure physique cible, favorisant ainsi la portabilité des applications de contrôle. Une implémentation du langage AirNet a également été réalisée. Ce prototype inclut en particulier une bibliothèque des primitives et opérateurs du langage, ainsi qu'un hyperviseur qui assure la composition des politiques de contrôle sur un réseau virtuel, et leur transposition (mapping) sur l'infrastructure physique. Afin de s'appuyer sur des contrôleurs SDN existants, l'hyperviseur inclut des modules d'intégration des contrôleurs POX et RYU. Une validation expérimentale a été menée sur différents cas d'étude (filtrage, répartition de charge, authentification dynamique, limitation de bande passante, etc.) dont les résultats attestent de la faisabilité de la solution. Enfin, des mesures de performances ont montré que le surcoût apporté par cette nouvelle couche d'abstraction est parfaitement acceptable. / The work of this thesis falls within the general context of software-defined networking (SDN). This new paradigm is one of the most significant initiatives to enable networks programmability or, in other words, to make current networks easier to configure, test, debug and evolve. Within an SDN ecosystem, the Northbound interface is used by network administrators to define policies and to program the control plane, it thus represents a major challenge. Ideally, this northbound interface should allow administrators to describe, as simply as possible, network services and their interactions, rather than specifying how and on what physical device they need to be deployed. Current related works show that this can be partly achieved through virtualization solutions and high-level domain specific languages (DSL). The objective of this thesis is to propose a new Northbound interface which will, on the one hand, rely on network virtualization and, on the other hand, expose its services as a domain specific programming language. Currently, several languages that include network virtualization solutions exist. Nevertheless, we believe that the abstract models they are using to build virtual networks remain inadequate to ensure simplicity, modularity and flexibility of virtual topologies and control programs. In this context, we propose a new network control language named AirNet. Our language is built on top of an abstraction model whose main feature is to provide a clear separation between edge and core network devices. This concept is a well-known and accepted idea within the network designer community. The originality of our contribution is to lift up this concept at the virtual control plane, not limiting it solely at the physical plane. Thus, logical boundaries between different types of policies will exist (control and data functions vs. transport functions), ensuring modularity and reusability of the control program. Moreover, in the proposed approach, the definition of the virtual network and policies is totally dissociated from the target physical infrastructure, promoting the portability of control applications. An implementation of the AirNet language has also been done. This prototype includes in particular a library that implements the primitives and operators of the language, and a hypervisor that achieves the composition of the control policies on the virtual network, and their mapping on the physical infrastructure. In order to rely on existing SDN controllers, the hypervisor includes integration modules for the POX and RYU controllers. An experimental validation has been also conducted on different use cases (filtering, load balancing, dynamic authentication, bandwidth throttling, etc.), whose results demonstrate the feasibility of our solution. Finally, performance measurements have shown that the additional cost brought by this new abstraction layer is perfectly acceptable.

nÃo hà / Taking as premise the need to make retirement plans structured in Defined Benefit (DB) and Hybrid (combination of a Defined Benefit Plan and Defined Contribution) under Private Pension, more attractive to sponsors and thereby reduce the use of model Defined Contribution (DC) commonly adopted in Brazil, considered by many scholars in the field not interesting to participants of benefit plans due to not effectively meet the purpose of social security, is presented in this study a proposal for readjustment rule of benefits that can be adopted both in DB plans as well as in Hybrid, but that relies on DC plans logic. It is an intermediate readjustment rule between the ones commonly adopted in DB plans and DC plans. Through this new rule, the benefits readjustment will be based on investments cumulative profitability, ranging from 0 to 100% of inflation, with the possibility of recovering inflationary losses in situations which investment performance exceeds the actuarial target. In order to demonstrate the viability of the proposed readjustment rule, results of a simulation study using the Monte Carlo method are presented, comparing benefits readjustment based on inflation rate (100% inflation) and readjustment based on the new rule. Simulation results point to possible lower difference, in 60 years, around 10% of benefit net value calculated on the new rule. Although new ruleâs adoption could result in reduction of the net benefit when compared with inflation-based readjustment rule, it appears more advantageous to the participant when compared with readjustment rule practiced in DC plans because it does not admit application of negative annual readjustment on benefits. The proposed rule establishes a point of convergence for both participants and sponsors interests. The readjustment mechanism here proposed represents an innovation to the Brazilian Private Pension system. / Tomando como premissa a necessidade de tornar os planos de previdÃncia estruturados nas modalidades de BenefÃcios Definidos (BD) e de ContribuiÃÃo VariÃvel (CV) mais atrativos para os patrocinadores, no Ãmbito da PrevidÃncia Complementar, e assim reduzir o uso do modelo de ContribuiÃÃo Definida (CD) adotado no Brasil o qual à considerado por muitos estudiosos da Ãrea desinteressante para participantes de planos de benefÃcios por nÃo atender efetivamente a finalidade previdenciÃria, à apresentada neste estudo uma proposta de regra de reajuste de benefÃcios que pode ser adotada tanto em planos do tipo BD como tambÃm CV, mas que se apÃia na lÃgica prÃpria de planos CD. Trata-se de uma regra de reajuste intermediÃria entre a adotada em planos BD e a adotada em planos CD. Por essa nova regra o reajuste dos benefÃcios serà baseado na rentabilidade acumulada dos investimentos, devendo se situar entre 0 e 100% da inflaÃÃo, com possibilidade de recomposiÃÃo de perdas inflacionÃrias em situaÃÃes em que o desempenho dos investimentos supera a meta de atuarial. Com o objetivo de demonstrar a viabilidade do emprego da regra de reajuste proposta, apresentam-se os resultados de um estudo de simulaÃÃo utilizando o mÃtodo Monte Carlo, atravÃs do qual se faz um comparativo entre o reajuste com base nessa regra e o reajuste de benefÃcios com base em Ãndice de inflaÃÃo (100% da inflaÃÃo). Os resultados obtidos apontam para a possibilidade de ocorrÃncia de diferenÃa a menor, em 60 anos, da ordem de 10% no valor lÃquido do benefÃcio apurado com base na regra proposta. Embora a adoÃÃo da nova regra possa implicar essa reduÃÃo no valor lÃquido do benefÃcio quando comparada com a regra de reajuste com base na inflaÃÃo, no entanto, comparativamente à regra de reajuste praticada nos planos CD, esta apresenta-se mais vantajosa para o participante porque nÃo admite a aplicaÃÃo de reajustes anuais negativos sobre os benefÃcios. A regra proposta possibilita situar em um ponto de convergÃncia de interesses participantes e patrocinadores. Esse mecanismo de reajuste proposto representa uma inovaÃÃo para o sistema de previdÃncia complementar brasileiro.