In this thesis for the degree of Master of Science from Stockholm University we explore the ideas of Symmetric Informationally Complete Positive Valued Measures (SIC-POVMs; commonly just SICs). This is an emerging concept in quantum information theory with ambitious claims, such as being a candidate for standard measurements [23] and perhaps being of importance to error correcting universal quantum computing [32]. While the definition of a SIC is exceedingly simple they have proven notoriously hard to find. This thesis explores new approaches to finding SICs. It is our ambition that this thesis shall provide the reader unfamiliar with SICs with a thorough introduction to the subject along with both the necessary quantum theory and group theory. We also hope to intrigue the reader already attuned to SICs by establishing a link between how close to a SIC a state is and how close to a MUS (Minimum Uncertainty State) it is. This is the main result of this thesis and we leave the reader with several open questions relating to this discovery to provoke further scrutiny of the matter. The thesis is divided into two parts: the first part provides the necessary background and theory; while the second part presents our results. There are also three appendices attached to this thesis where we delve into a discussion about computing power and also present some of the code used. Being appendices these are not essential to the thesis per se – they are rather supplied as a reference for the curious reader who might be interested in recreating some of our results.

<p>In wireless communication there is commonly much unnecessary communication made in directions not pointing towards the recipient. Normally omni directional antennas are being used which sends the same amount of energy in all directions equally. This waste of energy reduces the lifetime of battery powered units and causes more traffic collisions than necessary. One way of minimizing this wasted energy and traffic collisions, is to use another type of antenna called “smart antenna”. These antennas can use selectable radiation patterns depending on the situation and thus drastically minimize the unnecessary energy waste. Smart antennas also provide the ability to sense the direction of incoming signals which is favorable for physical layout mapping such as orientation.</p><p>This thesis presents the prototyping of a new type of smart antenna called the SPIDA smart antenna. This antenna is a cheap to produce smart antenna designed for the 2.4 GHz frequency band. The SPIDA smart antenna can use sixty-four different signal patterns with the control of six separate directional modes, amongst these patterns are six single direction patterns, an omni-directional signal pattern and fifty-six combi-direction patterns. The thesis presents complete building instructions, evaluation data and functional drivers for the SPIDA smart antenna.</p>

In wireless communication there is commonly much unnecessary communication made in directions not pointing towards the recipient. Normally omni directional antennas are being used which sends the same amount of energy in all directions equally. This waste of energy reduces the lifetime of battery powered units and causes more traffic collisions than necessary. One way of minimizing this wasted energy and traffic collisions, is to use another type of antenna called “smart antenna”. These antennas can use selectable radiation patterns depending on the situation and thus drastically minimize the unnecessary energy waste. Smart antennas also provide the ability to sense the direction of incoming signals which is favorable for physical layout mapping such as orientation. This thesis presents the prototyping of a new type of smart antenna called the SPIDA smart antenna. This antenna is a cheap to produce smart antenna designed for the 2.4 GHz frequency band. The SPIDA smart antenna can use sixty-four different signal patterns with the control of six separate directional modes, amongst these patterns are six single direction patterns, an omni-directional signal pattern and fifty-six combi-direction patterns. The thesis presents complete building instructions, evaluation data and functional drivers for the SPIDA smart antenna.

Cette thèse porte sur le développement d'une structure d'alimentation sans transformateur pour des décharges à barrière diélectrique (DBD). Une DBD est une charge permettant d'obtenir des plasmas froids à la pression atmosphérique. Ce dispositif est fortement capacitif et son alimentation doit délivrer plusieurs kilovolts pour allumer et entretenir la décharge. Cette haute tension est classiquement obtenue à l'aide d'un transformateur élévateur. Dans une première partie, nous montrons que les éléments parasites du transformateur impactent fortement le transfert d'énergie vers la décharge. C'est pourquoi dans une seconde partie, nous proposons une nouvelle topologie d'alimentation sans transformateur élévateur. Les caractéristiques fondamentales et le dimensionnement de notre alimentation sont obtenus par une analyse théorique. Dans cette topologie, les interrupteurs sont directement connectés à la DBD ; ils doivent donc supporter des tensions de plusieurs kilovolts. Il y a encore quelques années, il n'existait pas de semi-conducteur capable de supporter ce niveau de tension, à moins d'utiliser des interrupteurs fonctionnant à très basse fréquence. De récents progrès sur les matériaux semi-conducteurs ont permis d'élaborer des transistors et des diodes à base de carbure de silicium (SiC) capables de supporter des tensions allant jusqu'à 10 kV. Ce niveau de tension est tout à fait compatible avec la topologie d'alimentation proposée ici.Nous consacrerons la troisième partie du manuscrit à la mise en œuvre de notre convertisseur. Ce dernier, conçu à base de semi-conducteurs SiC, est fonctionnel et permet d'allumer une décharge. Cependant le fonctionnement initialement prévu est fortement affecté par la présence des capacités parasites notamment celles des interrupteurs. Nous détaillerons le rôle de chacune d'entre elles. Nous proposerons enfin des solutions permettant d'améliorer le transfert de puissance : mise en série de semi-conducteurs basses tensions, utilisation sur DBD de forte puissance... / This thesis focuses on the development of a dielectric barrier discharge (DBD) transformerless power supply. A DBD can produce cold plasma at atmospheric pressure. This device is a capacitive load, which must be supplied by a high voltage alternative source. This high voltage is classically obtained by amplifying a low level voltage with a step up transformer. In the first part, we show that the parasitic elements of the transformer limit the power transfer to the DBD load. This is why, in a second part, we propose a new topology without step-up transformer. A theoretical study of the converter allows to size our power supply and to deduce the fundamental characteristics of the latter. In our topology, the power switches are directly connected to the high voltage. A few years ago, it was inconceivable to connect directly a transistor to a high level of voltage (5kV), unless using very low frequency switches. Recent progress on semiconductor devices led to the development of transistors and diodes based on silicon carbide (SiC), which are able to hold up to 10kV. This voltage level is compatible with our topology.In the third part, we focus on the realization of our transformerless power supply and its operation. Our power supply based on 10 kV SiC semiconductors can ignite the discharge; however the parasitic capacitance and particularly those of the switches affect the power transfer. The role of each one of them is analyzed in detail.In the last part we propose solutions to improve the power delivered by this supply: series connection of lower voltage switches, supplying a high power DBD...

Detta examensarbete är en del av forskningsprojektet COMMAND som genomfördes av forskningsinstitutet RISE SICS Västerås tillsammans med SSAB under 2018 och 2019. Ett delmål med forskningsprojektet var att hjälpa industriföretag presentera mätvärden och maskindata på ett mer användarvänligt och överskådligt sätt. Examensarbetet har haft som mål att uppfylla detta mål genom att skapa graf som representerar data med punkter istället för linjer. I texten nedan kallar jag detta för Punktgraf då grafen baseras på punkter som segmenterar och komprimerar data för att skapa översikt.  Grundläggande principer för framtagandet av grafer studerades i “The Visual Display of Quantitative Information” och Colin Ware’s designprinciper om närhet, likhet och pop-out applicerades för att underlätta avläsning av grafen. En Unity-scen skapades för att snabbt generera exakt men simulerad data för att utvärdera punktgrafens potential. Det första testet visade att läsandet av grafen var ansträngande. Hög kognitiv belastning gjorde läsbarheten svårare snarare än lättare. Efter en uppdaterad version skapats genomfördes ett nytt test och intervju för att utvärdera resultatet av förändringarna. Efter dessa iterationer tog artefakten en mer användbar form som föreföll öka användarens förmåga att överblicka stora datamängder och upptäcka tidigare dolda mönster i stora dataset. Det identifierades också att punktgrafen skulle kunna bli ett användbart verktyg, inte bara för bevakning av industrimaskiner, utan också inom generell dataanalys. / This thesis work is part of the research project COMMAND that was conducted by the research institute RISE SICS Västerås together with SSAB during 2018 and 2019. One of the work-packages in the project was aimed to help industry companies present their machine data as an overview and in a more user friendly way. The  goal of this thesis work  was to make it easier to detect anomalies in the data for the purpose of predictive maintenance. The result from this thesis work is a type of graph that presents data in the form of stacked points rather than lines. I call this a “node based graph” as the nodes of the graph segment to compress the data to increase overview. To develop this artifact, literature such as “The Visual Display of Quantitative Information” and Colin Ware’s design principles of proximity, likeness and pop-out was applied to help form the graph. A Unity-scene was created to rapidly generate simulated but accurate real time data for visualization tests. The first test however showed an increased strain on the users ability to read the graph. High cognitive load made readability lower rather than higher. For this reason a secondary test was conducted to verify changes made to the artifact during the design process. After iterations were made the design took a more useful form that appeared to increased the users ability to overlook large data sets and detect patterns previously unseen. It also came to light that this particular type of presentation of data perhaps hold higher value outside the initial target audience, and that its redesign could turn it into a beneficial tool, not just monitoring of industrial machines, but for data analysis in general. / COMMAND - Communication and maintenance for the digital factory

This thesis examines two different approaches to parsing event-based vehicular signal data to produce input to a neural network prediction model: event parsing, where the data is kept unevenly spaced over the temporal domain, and slice parsing, where the data is made to be evenly spaced over the temporal domain instead. The dataset used as a basis for these experiments consists of a number of vehicular signal logs taken at Scania AB. Comparisons between the parsing methods have been made by first training long short-term memory (LSTM) recurrent neural networks (RNN) on each of the parsed datasets and then measuring the output error and resource costs of each such model after having validated them on a number of shared validation sets. The results from these tests clearly show that slice parsing compares favourably to event parsing. / Denna avhandling jämför två olika tillvägagångssätt vad gäller parsningen av händelsebaserad signaldata från fordon för att producera indata till en förutsägelsemodell i form av ett neuronnät, nämligen händelseparsning, där datan förblir ojämnt fördelad över tidsdomänen, och skivparsning, där datan är omgjord till att istället vara jämnt fördelad över tidsdomänen. Det dataset som används för dessa experiment är ett antal signalloggar från fordon som kommer från Scania. Jämförelser mellan parsningsmetoderna gjordes genom att först träna ett lång korttidsminne (LSTM) återkommande neuronnät (RNN) på vardera av de skapade dataseten för att sedan mäta utmatningsfelet och resurskostnader för varje modell efter att de validerats på en delad uppsättning av valideringsdata. Resultaten från dessa tester visar tydligt på att skivparsning står sig väl mot händelseparsning.