There are several standards for wireless communication. People that are involved in computers and networking recognize names like Bluetooth, HiperLAN and IEEE 802.11. The last one was standardized in 1997 [2,6]and has begun to reach acceptance as a solid ground for wireless networking. A fundamental part of an IEEE 802.11 node is the Medium Access Controller, or MAC. It establishes and controls communication with other nodes, using a physical layer unit. The work has been carried out as final project at Linkopings Universitet, it has been about the improvement of the functions of MAC layer. I have developed some of the required functions that PUM uses to interact with the MAC layer. Because of that, I have implemented the Reception functions of MAC layer, having the possibility of using short control frames RTS/CTS to minimize collision.

With the 1999 introduction of IEEE 802.11b, the 2.4 GHz Wireless Local Area Network (WLAN) standard, the WLAN market finally began to experience the growth levels that had been expected for so long. Now, 5 GHz solutions, with the IEEE 802.11a standard leading the way, offer higher throughput and more efficient use of the spectrum. Just as the 2.4 GHz band, the 5 GHz band is unlicensed. A common concern to all unlicensed bands is interference between devices using the spectrum. Furthermore, in the 5 GHz band, WLAN cells can interfere with radar systems operating at the same frequencies. This report describes a software model, WOK, suitable for simulations of IEEE 802.11a WLANs operating in various environments and under various ambient conditions. The WOK model can be configured extensively with respect to topology, traffic behavior, channel models, signal attenuation, interference sources and radar systems. Further, the concepts of Dynamic Frequency Selection (DFS) and link adaptation are explored in the context of the IEEE 802.11a standard. DFS aims to avoid channels occupied by radar systems and link adaptation aims to maximize the throughput based on current ambient conditions. A DFS algorithm and a link adaptation algorithm are implemented at the Medium Access Control (MAC) layer and evaluated using the WOK model.

Le devenir des branches artérielles émergentes de la proximité d’un anévrysme intracrânien et couvertes par un stent à diversion de flux lors le traitement de l’anévrysme reste controversé. Une recherche animalière de caractère translationnel a été conduite afin d’élucider le rôle du flux collatéral dans les changements hémodynamiques apportés par un stent a diversion de flux. La couverture néointimale relative aux modifications hémodynamiques aux ostia de ces artères a été également évaluée. Pour atteindre notre objectif, nous avons cherché à quantifier les changements hémodynamiques dans les artères couvertes à leurs origines et à quantifier leur surface de couverture par le tissu endothélial à 3 mois après le placement du stent à diversion de flux dans un modèle animal porcin.Méthodes Suivant une analyse de pouvoir statistique a priori, deux groupes (A, B), chacun contenant sept porcs de race large white, ont été créés, suivant un modèle de flux de circulation artérielle terminale ou anastomotique. Groupe A correspondait à une configuration artérielle de type anastomotique pour l’artère Pharyngienne ascendante droite et groupe B à une configuration terminale concernant la même branche ; cette configuration terminale a été créée par l’occlusion endovasculaire sélective des apports artériels collatéraux pour le territoire de suppléance de l’artère Pharyngienne ascendante droite. Ensuite, pour chacun des 14 animaux, un stent à diversion de flux a été placé dans la carotide interne droite couvrant ainsi l’ostium de l’artère pharyngienne ascendante homolatérale. Pour mesurer les vélocités à l’origine de cette artère, une séquence IRM de contraste de phase tridimensionnelle avec une résolution temporelle (4D) a été utilisée. Des valeurs ont été obtenues avant et après stenting. Trois mois plus tard, un travail de prélèvement anatomique suivi d’une analyse par microscopie à balayage anatomique a été a été réalisé. Une quantification surfacique a été ainsi obtenue permettant de déterminer la perméabilité des ostia des artères pharyngienne ascendante. Les données ont été ainsi analysées grâce à des tests de statistique descriptive et comparative des deux groupes prédéterminés. Des tests paramétriques et non paramétriques ont également été obtenus. Résultats La faisabilité a pu être obtenue dans tous les spécimens utilisés. Nous n’avons déploré aucune mortalité immédiate ni aucune occlusion intra-stent relatives à la procédure. Les séquences IRM de diffusion ont témoigné de l’absence d’ischémie distale à la phase aigue après la mise en place du stent, Immédiatement, en post stenting, le flux moyen dans les artères pharyngiennes ascendantes droites du groupe a été réduit d’une façon significative, quand on le compare à la valeur moyenne en pré- stenting [P = 0.0008, pouvoir statistique: 0.9548]. Au contraire, le flux moyen dans les artères pharyngiennes ascendantes droites du groupe B est resté comparable à la valeur moyenne pré- stenting. Apres trois mois de suivi, la valeur moyenne de surface perméable était significativement plus élevée dans le groupe B (527,911 ± 306,229 μm2) que dans le groupe A (89,329 ± 59,762 μm2) [P< 0.01, power: 1.00], malgré la similarité les dimensions artérielles initiales (pré-stenting) dans les deux groupes. Une corrélation positive significative a été retrouvée entre les deux groupes concernant le flux moyen post stenting et la surface moyenne de couverture aux ostia, à trois mois de suivi. / The outcome of jailing arterial branches that emerge near intracranial aneurysms during flow-diverting stent deployment remains controversial. We report an animal research study aiming to elucidate the role of collateral supply in the hemodynamic changes and neointimal modifications resulting from jailing arteries with flow-diverting stents. To serve this purpose, we sought to quantify the hemodynamic changes at the jailed arterial branches immediately after stenting, as well as quantify the ostia surface values at three months post-stenting, in the presence or absence of collateral arterial flow. Methods After a priori power analysis, two groups (A, B), each containing seven large white swine, were created according to an animal flow model for terminal and anastomotic arterial circulation. Group A corresponded to an arterial configuration with anastomotic type of arterial supply for the territory of the right Ascending Pharyngeal artery (APhA) and group B to an arterial configuration of terminal type of arterial supply for the territory of the right APhA. Subsequently, all animals were stented by flow-diverting stents, jailing the right ascending pharyngeal arteries. Mean flow rates and velocities inside the jailed branches were quantified before and after stenting by time-resolved, 3D, phase contrast MRA. After three months the jailed ostia surface values were quantified on scanning electron microscopic images. The data were analyzed using descriptive statistics and group comparisons with parametric and non-parametric tests.Results Endovascular procedures were feasible, without in situ thrombus formation or ischemic DWI findings on post-procedure MRIs. Immediately following stenting, mean flow rate values at the jailed right ascending pharyngeal arteries were reduced in group A, as compared to the pre-stenting values [P = 0.0008, power: 0.9548]. In contrast, mean flow rates for group B remained similar to the pre-stenting values. At three months post-stenting, mean ostia surface values were significantly higher for group B (527,911 ± 306,229 μm2) than for group A (89,329 ± 59,762 μm2) [P< 0.01, power: 1.00], even though the initial dimensions of the jailed ostia were similar between groups. A statistically significant correlation was found between group (A or B), mean flow rates post-stenting and ostia surface values at three months. ConclusionWhen important collateral supply was present, jailing side arteries with flow-diverters resulted in an immediate, significant reduction in flow rate inside these arteries, as compared to the pre-stenting values. In contrast, when competitive flow was absent, jailing did not result in significant flow rate reductions inside the jailed arteries. Ostium surface values at three months were significantly higher in the terminal group of jailed arteries, compared to the anastomotic group and strongly correlated with the velocity value reductions post- stenting. Key words: flow-diverting stent, collateral arteries, endothelialization, ostium, embolization, magnetic resonance angiography, magnetic resonance imaging

Tato práce se zabývá analyzováním IEEE 802.1Q standardu TSN skupiny a návrhem testovacího modulu. Testovací modul je napsán v jazyku VHDL a je možné jej implementovat do Intel Stratix® V GX FPGA (5SGXEA7N2F45C2) vývojové desky. Standard IEEE 802.1Q (TSN) definuje deterministickou komunikace přes Ethernet sít, v reálném čase, požíváním globálního času a správným rozvrhem vysíláním a příjmem zpráv. Hlavní funkce tohoto standardu jsou: časová synchronizace, plánování provozu a konfigurace sítě. Každá z těchto funkcí je definovaná pomocí více různých podskupin tohoto standardu. Podle definice IEEE 802.1Q standardu je možno tyto podskupiny vzájemně libovolně kombinovat. Některé podskupiny standardu nemohou fungovat nezávisle, musí využívat funkce jiných podskupin standardu. Realizace funkce podskupin standardu je možná softwarově, hardwarově, nebo jejich kombinací. Na základě výše uvedených fakt, implementace podskupin standardu, které jsou softwarově související, byly vyloučené. Taky byly vyloučené podskupiny standardů, které jsou závislé na jiných podskupinách. IEEE 802.1Qbu byl vybrán jako vhodná část pro realizaci hardwarového testu. Různé způsoby testování byly vysvětleny jako DFT, BIST, ATPG a další jiné techniky. Pro hardwarové testování byla vybrána „Protocol Aware (PA)“technika, protože tato technika zrychluje testování, dovoluje opakovanou použitelnost a taky zkracuje dobu uvedení na trh. Testovací modul se skládá ze dvou objektů (generátor a monitor), které mají implementovanou IEEE 802.1Qbu podskupinu standardu. Funkce generátoru je vygenerovat náhodné nebo nenáhodné impulzy a potom je poslat do testovaného zařízeni ve správném definovaném protokolu. Funkce monitoru je přijat ethernet rámce a ověřit jejich správnost. Objekty jsou navrhnuty stejným způsobem na „TOP“úrovni a skládají se ze čtyř modulů: Avalon MM rozhraní, dvou šablon a jednoho portu. Avalon MM rozhraní bylo vytvořeno pro komunikaci softwaru s hardwarem. Tento modul přijme pakety ze softwaru a potom je dekóduje podle definovaného protokolu a „pod-protokolu “. „Pod-protokol“se skládá z příkazu a hodnoty daného příkazu. Podle dekódovaného příkazu a hodnot daných příkazem je kontrolovaný celý objekt. Šablona se používá na generování nebo ověřování náhodných nebo nenáhodných dat. Dvě šablony byly implementovány pro expresní ověřování nebo preempční transakce, definované IEEE 802.1Qbu. Porty byly vytvořené pro komunikaci mezi testovaným zařízením a šablonou podle daného standardu. Port „generátor“má za úkol vybrat a vyslat rámce podle priority a času vysílaní. Port „monitor“přijme rámce do „content-addressable memory”, která ověřuje priority rámce a podle toho je posílá do správné šablony. Výsledky prokázaly, že tato testovací technika dosahuje vysoké rychlosti a rychlé implementace.

In this work I aimed at designing a universal system for testing either STM32F407/417 by STMicroelectronics and later various sensors and communication buses. The result then is a main board with many specific connectors for individual buses even with connectors making all I/O pins accessible at the same time. Thanks to advanced switching regulators the power supply is capable of accepting a wide range of sources like single Li-Ion cell, pair of alkaline cells, 12V Lead battery, common wall power adapters (both DC and AC up to 15 Vpp ), USB, laboratory power supplies with multiple outputs and finally POE (Power Over Ethernet). Supply voltages are supervised by voltage comparators with an optical signalisation. (It is possible to determine the sick branch without a measuring instrument and blowing components in the most cases.) Another important parameter was a robustness of the supply and communication lines. There is a number of TVSs, chokes, and big and low ESR capacitors A PC software is intended for a basic functionality demonstration only.

The diploma thesis deals with the theoretical definition of passive optical networks, furthermore the description of methods of channel bundling in passive optical networks and the coexistence and migration between standards. The main essence of this work is the XG-PON (10-Gigabit-capable Passive Optical Network) standard. This standard is generally defined along with a description of the physical layer. The transport layer is detailed analysis. There is a description of conditions, under which the Optical Network Unit pass through, when is activated. Additionally, this diploma thesis focuses on the processes of connecting Optical Network Units to the Passive Optical Networks and the timing relationships between Optical Network Units and Optical Line Terminal. The simulations demonstrate that as the number of simultaneous connections to Optical Network Unit increase, longer wait time for each additional connection becomes. This also solves the collision conditions, that might arise in communication and the equalization delay. Finally, the diploma thesis deals with the influence of a refractive index on timing relationships.