Dans le but d’améliorer la disponibilité des services fournis par un récepteur, la conception d’un récepteur GNSS permettant de recevoir plusieurs signaux de toutes les bandes simultanément semble être la solution. Une architecture à sous échantillonnage RF optimisée de type SDR (Software Defined Radio) comportant un étage RF intégrable et reconfigurable et un étage de traitement numérique avec une implémentation logicielle du traitement en bande de base est défini pour ce récepteur GNSS, tout en répondant aux exigences des spécifications des standards GNSS : des réseaux radio cellulaires : GPS, Glonass, Galileo, Beidou. Un choix des composants discrets suite au dimensionnement system est effectué et ceci pour installer un prototype de validation expérimental. Ensuite nous nous s’intéressons à la caractérisation de la chaine RF afin d’étudier les limitations causés par la non linéarité et d’étudier la stabilité du prototype proposé. Un étage de traitement numérique des signaux IF, capturés à la sortie de l’ADC, est implémenté sous Matlab. L’acquisition de ces données permet la détermination des satellites visible à un instant donné qui nous permet éventuellement la détermination d’une position / In order to improve the availability of services provided by a receiver, designing a GNSS receiver to collect multiple signals from all bands simultaneously seems to be the solution. An optimized software-defined RF (SDR) sub-sampling architecture with an integral and reconfigurable RF stage and a digital processing stage with a software implementation of the baseband processing is defined for this GNSS receiver, while meeting the requirements GNSS standards specifications: cellular radio networks: GPS, Glonass, Galileo, Beidou. Many discrete components are selected after system dimensioning. Thus, experimental validation prototype is installed. Then we are interested in the characterization of the RF front-end in order to determine the limitations caused by the nonlinearity and to study the stability of the proposed prototype. A stage of digital processing of the IF signals, captured at the ADC output, is implemented under Matlab software. The acquisition of these data allows the determination of satellites visible at a given instant that allows us to determine a position

Data Centers (DCs) have become an intrinsic element of emerging technologies such as big data, artificial intelligence, cloud services; all of which entails interconnected and sophisticated computing and storage resources. Recent studies of conventional data center networks (DCNs) revealed two key challenges: a biased distribution of inter-rack traffic and unidentified flow classes: delay sensitive mice flows (MFs) and throughput-hungry elephant flows (EFs). Unfortunately, existing DCN topologies support only uniform distribution of capacities, provide limited bandwidth flexibilities and lacks of efficient flow classification mechanism. Fortunately, wireless DCs can leverage wireless communication emerging technologies, such as multi-terabit free-space optic (FSO), to provide flexible and reconfigurable DCN topologies. It is worth noting that indoor FSO links are less vulnerable to outdoor FSO channel impairments. Consequently, indoor FSO links are more robust and can offer high bandwidths with long stability, which can further be enhanced with wavelength division multiplexing (WDM) methods. In this thesis, we alleviate the bandwidth inefficiency by FSO links that have the desired agility by allocating the transmission powers to adapt link capacity for dynamically changing traffic conditions, and to reduce the maintenance costs and overhead. While routing the two classes along the same path causes unpleasant consequences, the DC researchers proposed traffic management solutions to treat them separately. However, the solutions either suffer from packet reordering and high queuing delay, or lack of accurate visibility and estimation on end-to-end path status. Alternatively, we leverage WDM to design elastic network topologies (i.e., part of the wavelengths are assigned to route MFs and the remaining for EFs). Since bandwidth demands can be lower than available capacity of WDM channels, we use traffic grooming to aggregate multiple flows into a larger flow and to enhance the link utilization. On the other hand, to reap the benefits of the proposed WDM isolated topology, an accurate and fast EF detection mechanism is necessary. Accordingly, we propose a scheme that uses TCP communication behavior and collect indicative packets for its flow classification algorithm, it demonstrates perfect flow classification accuracy, and is in order of magnitudes faster than existing solutions with low communication and computation overhead.

This master's thesis deals with the description of LPWAN technologies focused on LoRaWAN technology in the theoretical part. The next part deals with description and analyzing of LoRaWAN protocol. In theoretical part also security elements of the LoRaWAN protocol are discussed and LoRaWAN 1.0.2 and 1.1.x versions are compared. The thesis also deals with LoRaWAN tapping and its decryption, both on the physical layer and the MAC protocol layer LoRaWAN. The thesis shows how to use software-defined radio to listen to LoRaWAN communication. Lastly, a replay attack and fake message over the fake session are performed

High cost is a current problem with modern radar systems. Software-defined radios (SDRs) offer a possible solution for low-cost customizable radar systems. An SDR is a radio communi- cation system where, instead of the traditional radio components implemented in hardware, many of the components are implemented in software on a computer or embedded system. Although SDRs were originally designed for wireless communication systems, the firmware of an SDR can be configured into a radar system. With new companies entering the market, various types of low- cost SDRs have emerged. This thesis explores the use of a LimeSDR-Mini in a short-range radar through open software tools and custom code. The LimeSDR-Mini is successfully shown to detect targets at a short range. However, due to the instability of the LimeSDR-Mini, the consistent detection of a target is not possible. This thesis shows how the LimeSDR is characterized and how timing synchronization and instability issues are mitigated. The LimeSDR-Mini falls short of operating reliable in a radar system and other SDR boards need to be explored as viable options. Test setups using coaxial cables and test setups using antennas in an outdoor environment show the instability of the LimeSDR-Mini. The transmitter and the receiver are asynchronous. The timing difference varies slightly from run to run, which results in issues that are exacerbated in a short-range radar. The bleed-through signal is the signal leakage from the transmitter to the receiver. The bleed-through signal prevents the detection of targets at a short-range. Feed-through nulling is a signal processing technique used to eliminate the bleed-through signal so that short- range targets can be detected. The instability of the LimeSDR-Mini reduces the effectiveness of feed-through nulling techniques.

<p>Pametna elektroenergetska mreža predstavlja mrežu nove generacije koja treba da bude efikasna, proširiva, pouzdana i jednostavna za upravljanje. Pametnu mrežu karakteriše veliki broj uređaja i dvosmerna komunikacija sa njima. Ovi uređaji će generisati ogromne količine podataka koje je potrebno pročitati i transportovati do kontrolnog centra, za šta je neophodna odgovarajuća komunikaciona infrastruktura koja obezbeđuje adekvatan kvalitet usluge. U ovoj disertaciji je prikazano rešenje za obezbeđivanje kvaliteta usluge sabraćaja sa dinamičkim promenama prioriteta i propusnog opsega bazirano na programabilnim računarskim mrežama. Takođe je razvijena platforma za evaluaciju komunikacione infrastrukture pametnih mreža kako bi se omogućilo jednostavnije emuliranje različitih mrežnih topologija za potrebe razvoja novih algoritama upravljanja. Performanse rešenja su potvrđene putem šest testnih scenarija i pokazano je da predstavljeno rešenje daje bolje rezultate za sve scenarije sa aspekta obezbeđivanja propusnog opsega i mrežnog kašnjenja.</p> / <p>Smart grid represents the next generation power network which should be efficient, extensible, reliable and easy to manage. The smart grid will have a great number of devices with two-way communication. These devices will generate large amount of data that needs to be read and transported to utility control center, which further requires adequate communication infrastructure with appropriate quality of service. This dissertation presents a solution for providing quality of service for traffic with dynamic priority and bandwidth requirements, based on software defined networks. The platform for smart grid communication infrastructure evaluation is developed to enable easy emulation of different network topologies for the purpose of developing new control algorithms. Solution performance is verified using six test scenarios and it is shown that the proposed solution gives better results for all scenarios from the aspect of bandwidth provision and network latency.</p>

Die vorliegende Arbeit behandelt die Anlage von Pensionsvermögen im Rahmen von Contractual Trust Arrangements. Es wird untersucht, welche Anlagestrategien sich unter Berücksichtigung bilanzieller, verpflichtungs- und vermögensseitiger Rahmenbedingungen zur Anlage von Pensionsvermögen eignen. Anhand eines geeigneten Anlagemodells für Pensionsvermögen und der Durchführung einer stochastischen Simulation wird analysiert, welchen Einfluss unterschiedliche Anlagestrategien auf die Entwicklung des Pensionsvermögens haben. Die Arbeit geht zunächst den Hintergrund der betrieblichen Altersversorgung und Contractual Trust Arrangements in Deutschland ein. Zur Abbildung der Verpflichtungsseite und der Mitarbeiterstruktur des Unternehmens wird unter Einbezug aktuarischer Ansätze ein Mitarbeitermodell entwickelt. Das in der Arbeit entwickelte Portfoliomodell integriert die Verpflichtungs- und Vermögensseite und zeigt, wie das Vermögen zur Deckung leistungsorientierter Zusagen zur betrieblichen Altersversorgung unter Einbezug der Unternehmensperspektive mit Hilfe dynamischer Risikonebenbedingungen geeignet angelegt werden kann.

Die vorliegende Arbeit behandelt die Anlage von Pensionsvermögen im Rahmen von Contractual Trust Arrangements. Es wird untersucht, welche Anlagestrategien sich unter Berücksichtigung bilanzieller, verpflichtungs- und vermögensseitiger Rahmenbedingungen zur Anlage von Pensionsvermögen eignen. Anhand eines geeigneten Anlagemodells für Pensionsvermögen und der Durchführung einer stochastischen Simulation wird analysiert, welchen Einfluss unterschiedliche Anlagestrategien auf die Entwicklung des Pensionsvermögens haben. Die Arbeit geht zunächst auf den Hintergrund der betrieblichen Altersversorgung und Contractual Trust Arrangements in Deutschland ein. Zur Abbildung der Verpflichtungsseite und der Mitarbeiterstruktur des Unternehmens wird unter Einbezug aktuarischer Ansätze ein Mitarbeitermodell entwickelt. Das in der Arbeit entwickelte Portfoliomodell integriert die Verpflichtungs- und Vermögensseite und zeigt, wie das Vermögen zur Deckung leistungsorientierter Zusagen zur betrieblichen Altersversorgung unter Einbezug der Unternehmensperspektive mit Hilfe dynamischer Risikonebenbedingungen geeignet angelegt werden kann.

No description available.

No description available.

No description available.