The object of this work is to study the IEEE 802.11ac standard, paying attention to the issue of the physical layer standard, to study in detail the use of MIMO and implement this technology into framework of WIFI simulator.

Embedded multi-core systems are implemented as systems-on-chip that rely on packet store-and-forward networks-on-chip for communications. These systems do not use buses nor global clock. Instead routers are used to move data between the cores and each core uses its own local clock. This implies concurrent asynchronous computing. Implementing algorithms in such systems is very much facilitated using dataflow concepts. In this work, we propose a methodology for implementing algorithms on dataflow platforms. The methodology can be applied to multi-threaded, multi-core platforms or a combination of these platforms as well. This methodology is based on a novel dataflow graph representation of the algorithm. We applied the proposed methodology to obtain a novel dataflow multi-core computing model for the secure hash algorithm-3. The resulting hardware was implemented in FPGA to verify the performance parameters. The proposed model of computation has advantages such as flexible I/O timing in term of scheduling policy, execution of tasks as soon as possible, and self-timed event-driven system. In other words, I/O timing and correctness of algorithm evaluation are dissociated in this work. The main advantage of this proposal is the ability to dynamically obfuscate algorithm evaluation to thwart side-channel attacks without having to redesign the system. This has important implications for cryptographic applications. Also, the dissertation proposes four countermeasure techniques against side-channel attacks for SHA-3 hashing. The countermeasure techniques are based on choosing stochastic or deterministic input data scheduling strategies. Extensive simulations of the SHA-3 algorithm and the proposed countermeasures approaches were performed using object-oriented MATLAB models to verify and validate the effectiveness of the techniques. The design immunity for the proposed countermeasures is assessed. / Graduate / 2020-11-19

Ingeniero Civil Mecánico / El informe que a continuación se presenta, expone las directrices que guiarán el trabajo de tesis: Análisis del comportamiento colectivo presentado por robots vibracionales . Este trabajo de título tiene por objeto realizar el estudio y modelamiento del comportamiento individual y colectivo presentado por una serie de robots vibracionales autónomos de geometría cúbica. Como punto inicial, se considera el diseño del cuerpo de los robots en el programa Solid- Works para su posterior construcción en las impresoras tridimensionales modelo MakerBot 2, disponibles en el laboratorio de fabricación digital (FABLAB). Motores vibradores de celular servirán como elemento motriz y pilas de reloj serán la fuente de energía de los robots. La primera etapa del proceso de modelamiento se realizará mediante el rastreo de los cubos utilizando la cámara Optitrack Trio , gracias a la cual será posible conocer las trayectorias y velocidades de los robots. Con estos datos, se obtendrá un modelo estadístico de la cinemática de los robots (trayectoria y velocidad) mediante el software Matlab . En paralelo, se desarrollará una simulación realista de los cubos utilizando la librería Open Dynamics Engine (ODE) perteneciente al lenguaje de programación C++. Esta simulación será validada al enfrentar los datos obtenidos con las mediciones realizadas a los robots por medio de la cámara Optitrack Trio . En una segunda etapa, se dotará a estos robots modulares de interacciones para determinar la infl uencia de las mismas en el comportamiento presentado por los robots. La determinación de patrones de ordenamiento, al igual que en la primera etapa, será determinada mediante el seguimiento obtenido mediante el software Motive perteneciente a la marca Optitrack . Tal como en la primera etapa, se implementarán simulaciones realistas de los robots y sus interacciones para luego realizar la validación pertinente. Finalmente, se procederá a formular un modelo estocástico del movimiento de estos robots que servirá como herramienta para futuras investigaciones dentro del campo de la robótica modular.

Epithelial wound healing requires the coordination of cells to migrate as a unit over the basement membrane after injury. An excellent model tissue is the corneal epithelium, which is an avascular stratified squamous tissue that responds to growth factors and nucleotides when the epithelial barrier is damaged. One signal that has a ubiquitous response in epithelial wound healing is the cellular release of the nucleotide ATP, which may occur because of mechanics forces and/or change in cell shape. Within milliseconds to seconds after injury, extracellular ATP binds to purinoreceptors and triggers a transient Ca2+ wave, which is used by cells to transduce mechanical signals into chemical signals and alter signaling pathways. To understand the process of this coordinated movement, it is critical to study the dynamics of cell-cell communication. In this study we developed a novel method to identify and characterize the degree of cell-cell communication that occurs through sustained Ca2+ mobilizations after injury, which are concentrated along the epithelial wound edge and reduced in cells distal to the injury. Using MATLAB analyses, we generated profiles of the sustained Ca2+ mobilizations, and demonstrated that the Ca2+ response was replicated in ex vivo organ culture models. The sustained Ca2+ mobilizations were present also after stimulation with either BzATP or UTP, which are agonists of P2X7 and P2Y2 respectively. The probability that cells would communicate was greater in response to BzATP compared to UTP. The specificity of these ligands was demonstrated using competitive inhibitors of P2Y2 and P2X7 receptors, AR-C 118925XX and A438079, respectively. An inhibitor of pannexin-1, 10Panx, attenuated both wound closure and BzATP agonist-initiated response. These sustained mobilizations are correlated with changes in cellular morphology and motility, which were prominent in cells at the leading edge of the wound during cell migration. Together, our results demonstrate that the sustained Ca2+ mobilizations mediated by purinoreceptors and pannexins are a vital component in regulating the long-term response to injury, as studied in organ culture.

De flesta tvivlar inte på att klimatförändringarna är märkbara. Många vet däremot inte är att metan (CH4 ) är en mycket viktig växthusgas som påverkar klimatförändringen och som inte får försummas. I denna uppsats behandlar jag växthusgasen metan. Det förklaras var och hur metan bildas, var den släpps ut och absorberas samt vilket inflytande människor har på koncentrationen av metan i atmosfären. Med hjälp av en datorsimulering i MATLAB simuleras och utvärderas olika scenarier. Dessa scenarier sträcker sig från den förindustriella eran, genom nutiden, till möjliga framtidsscenarier. Utifrån mätdatan går det att uppskatta hur stor inverkan metan har på den globala uppvärmningen och därmed på klimatförändringen.

The Advanced Telescope for High-Energy Astrophysics (ATHENA) has been selected as the second large (L-class) mission designed to address the Cosmic Vision science theme “The Hot and Energetic Universe”. The European Space Agency has produced a Mission Observation Plan which contains objectives and constraints of the mission. In addition, this plan includes a representative sequence of targets, the Mock Observation Sequence, which defines the order in which ATHENA has to observe the targets. The feasibility of the Mock Observation Plan has to be assessed and the Mission Timeline Simulator has been designed for this purpose. It is a tool developed by Airbus DS that includes all the spacecraft operations. The analysis of the Mock Observation Plan in the Mission Timeline Simulator showed that the ATHENA’s line of sight points into the sun during some observations. This would lead to a loss of the whole mission since sunlight damages the instruments. Consequently, a new Observation Sequence has been produced by Airbus DS, in which the spacecraft does not point to the sun. However, this new sequence does not meet one important requirement: the operational availability shall be above 90%. The operational availability is defined by the percentage of the total time which is used for science observation. The version at the start of the thesis of the artificial case study but representative to the ATHENA mission achieved a value of 87.3 %. One of the main objectives of this thesis is therefore to obtain a sequence that meets the operational availability requirement with the final goal of generating a functional timeline of several days. If any interrupt occurs to the timeline (Targets of Opportunity, safe mode events, etc.), the spacecraft shall be able to find the way back to the optimal timeline or replan a new one. The current status includes these events but the timeline does not get interrupted. In this aspect, the currently implemented Greedy algorithm, that chooses the observation sequence, must be extended in branch and horizon. In order to achieve these objectives, a Beam Search algorithm has been developed and implemented in the Mission Timeline Simulator. The operational availability has been increased by incrementing the width search (branching factor). The depth search (horizon factor) allows the user to restrict the longitude of the timeline in terms of number of targets. A first implementation not including interrupts was analysed and an operational availability higher than 90% was achieved. A second implementation with a functional timeline considering interrupts shows a decrease in the operational availability, which does not reach 90%; nevertheless improving the results of the previous version with a final operational availability of 89.24%. Note that this is a representative case study of the mission. The Beam Search algorithm has been demonstrated to be suitable for the defined problem and a future sensitivity analysis of different parameters, such as depth and width search, could increase further the performance of the algorithm and therefore the simulation results. / ATHENA mission

This thesis explores the use of the Naïve Bayesian classifier as a method of determining high-level information about secondary users in a Dynamic Spectrum Access (DSA) network using a low complexity channel sensing method.  With a growing number of users generating an increased demand for broadband access, determining an efficient method for utilizing the limited available broadband is a developing current and future issue.  One possible solution is DSA, which we simulate using the Universal DSA Network Simulator (UDNS), created by our team at Virginia Tech. However, DSA requires user devices to monitor large amounts of bandwidth, and the user devices are often limited in their acceptable size, weight, and power.  This greatly limits the usable bandwidth when using complex channel sensing methods.  Therefore, this thesis focuses on energy detection for channel sensing. Constraining computing requirements by operating with limited spectrum sensing equipment allows for efficient use of limited broadband by user devices.  The research on using the Naïve Bayesian classifier coupled with energy detection and the UDNS serves as a strong starting point for supplementary work in the area of radio classification. / Master of Science

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Sammanfattning För den dubbelstakande längdåkaren är överansträngda muskler ett pågående problem. På uppdrag av Johnny Nilsson – lektor vid Gymnastik och Idrottshögskolan (GIH) i Stockholm – har en prototyp tagits fram för att övervaka överansträngning hos musculus trapezius (m. trapezius) med hjälp av elektromyografi (EMG). Prototypen kravspecificerades och projektgruppen fick uppdraget att med fria händer utveckla en rörelsereferens med mål att validera var i rörelsen som längdåkaren överanstränger muskeln. För att bygga elektromyografen användes den öppna hårdvaran Arduino som med EMG-modul kunde samla in data genom ytelektroder fästa på m. trapezius. För att uppfylla de funktionskrav som ställdes på rörelsereferensen byggdes en elektrogoniometer där en vridpotentiometer fästes på armbågsleden och mätte dess flexions- och extensionsvinkel. Arduinon programmerades genom dess egen programmeringsmiljö och ett SD-kort installerades på mikrokontrollerkortet för insamling av rådata; efterbehandlingen och presentation av data skedde sedan i Matlab. Med hjälp av Peter Arfert vid medicinsk bildteknik KTH designades ett 3D-utskrivet hölje till EMG-prototypen. Slutligen fick projektgruppen möjlighet att besöka LIVI-laboratoriet i Falun där längdåkning utövades på rullband. Studiebesöket gjorde det möjligt att praktiskt utföra testförsök av prototypen i dess tilltänkta testmiljö och samla in rådata. / Overwork of muscle can be a problem for the double poling cross country skier potentially resultingin lower efficiency. An assignment was established – on behalf of Johnny Nilsson at Gymnastik- ochIdrottshögskolan (GIH) in Stockholm – in order to build a prototype able to monitor and record datafrom musculus trapezius (m. trapezius) through the use of electromyography (EMG). The EMG wasmade using the open source hardware Arduino. The prototype was able to record bilateralmeasurements with the use of EMG-shields, where surface-electrodes were attached to m. trapezius.By creating a prototype based on a rotary potentiometer attached to the elbow joint a reference ofmovement was established by measuring the extension and flexion angle of the elbow. Arduino’s ownIDE was used to program the hardware of the prototype and data was post-processed and presented inMatlab. Data was transferred with the use of an SD-card reader installed on the microcontroller. Withthe help of Peter Arfert at KTH, a 3D-printed model was made for the prototype. The final prototypewas attached to an elite level cross-country skier and tested on a professional treadmill at the LIVIlaboratory in Falun, Sweden. Raw-data was successfully recorded during these trials.