Au cours de ce travail de thèse, nous nous sommes focalisés sur deux aspects de la RMN du solide: i) la RMN double-résonance de noyaux de fréquences de Larmor proches, ii) la quantitativité des spectres RMN sous polarisation croisée (CPMAS). L’emploi d’une sonde RMN solide prototype multicanaux (1H/19F/X/Y/Z) nous a permis de développer des outils RMN originaux pour la caractérisation de matériaux fluorés et ou hétérogènes (principes actifs, matériaux poreux, polymères), notamment le triple transfert de polarisation (1H, 19F) -13C, le double-transfert en cascade, les découplages multiples, et autres expériences de double-résonance 1H-19F ou 13C-27Al. La séquence multiCP a ensuite été évaluée pour l’obtention de spectre RMN 13C ou 29Si quantitatifs et la caractérisation de matériaux ayant des temps de relaxation contrastés. Nous avons montré que la condition pour obtenir des spectres RMN multiCP quantitatifs est la présence d’un bain de spins 1H dense. Des mesures quantitatives pour des composés purs (acides aminés, principes actifs, excipients, polymères inorganiques) ou en mélanges ont ainsi été obtenues. Le multiCP a ensuite été utilisé pour caractériser la structure locale de polymères siliciés et la nature fine du système de protons dans des membranes de Nafion. Dans la continuité, nous avons étudié une formulation pharmaceutique. Dans ce système hétérogène, nous avons profité des contrastes de temps de relaxation pour distinguer et quantifier les molécules de principe actif à l’intérieur ou en dehors du surfactant. Nous avons également caractérisé les interactions de la molécule avec le surfactant et suivi sa libération dans différents milieux mimant les milieux physiologiques. L’ensemble de ces travaux offre de nouveaux outils RMN pour la caractérisation de la structure locale de matériaux hétérogènes. / During this work, two aspects of solid-state NMR have been investigated: i) double-resonance NMR of nuclei with close Larmor frequencies, ii) quantitative cross-polarization (CPMAS) measurements. The use of a prototype multichannel solid NMR probe (1H/19F/X/Y/Z) has allowed the development of original NMR tools for the structural characterization of fluorinated or heterogeneous materials (active principles, porous solids, polymers), in particular the triple polarization transfer (1H, 19F) -13C, double-transfer ‘en cascade’, multiple decoupling, and other 1H-19F ou 13C-27Al double-resonance experiments. The multiCP experiment has then been evaluated to get quantitative 13C and 29Si NMR spectra and to characterize materials with contrasted relaxation times. We have shown that the presence of dense proton bath was key to get quantitative data. Quantitative measurements were then obtained for pure solids (aminoacids, active principles, excipients, inorganic polymers) and mixtures. The multiCP has then been used to characterize the local structure of siliceous polymers and the nature of the proton spin system in Nafion membranes. Finally, we have studied a pharmaceutical formulation. In this heterogenous system, we have taken benefit from the contrasted relaxation times to distinguish molecules present inside or outside the surfactant. We have also characterized the interactions between the active principle and the surfactant and followed the drug release in various physiological media. The ensemble of this work provides new NMR tools for the characterization of the local structure of heterogeneous materials.

No description available.

Studying whether new trading rules provide higher returns than the buy-and-hold strategy is relevant for both finance theory and the asset management field. In this thesis, we examine the profitability of the newly proposed trading strategy based on the concept of price overreaction on eight developed stock indices. In comparison to other studies, we extend a definition of price overreaction with an inclusion of a minimum volatility threshold. Based on the Ordinary Least Squares model, we find that a volatility condition significantly improves the predictability of return reversals after positive price overreaction. For comparison with the buy-and-hold, we use Hansen's Superior Predictive Ability test that corrects the data snooping bias. Despite better annualised returns during in-sample and out-of-sample periods, the results show that the proposed strategy is not superior to the buy-and-hold at any stock index due to heavy reliance on the predictions of the largest declines. Nevertheless, we confirm the effect of decoupling (flight to quality) that can positively affect our strategy, but only when we do not take into account transaction costs. In the end, we summarize behavioural concepts that lie behind our strategy as the overreaction and decoupling are mostly justified with cognitive biases.

No description available.

The field of sustainability accounting and reporting has developed immensely during the past couple of decades. Various reporting guidelines, recommendations, and standards had hit the market recently. However, Global Reporting Initiative (GRI) has remained the most widely used framework for reporting sustainability and is considered a standard for reporting sustainability. Thus, using GRI 11: oil and gas standard as a proxy, the research was aimed to investigate, if standardization of sustainability reporting is perceived as an incentive, or poses a ceiling effect to potential sustainability reporting and performance. Thereby answering the following questions; (1) Is the organization willing to (or can) do more or less than that is required to be reported as per GRI Framework, in terms of reporting? (2) How does the company perceive the shift from GRI general standards to Sector-Specific Standards with respect to sustainability performanceA case study is conducted on an oil and gas EPC using qualitative research methodology. The data is collected through semi-structured interviews and three sustainability reports of the same organization. It was found that despite the apparent willingness of doing more than what is required to be reported by the standard, KPIs w.r.t. industry relevance are under-reported. Furthermore, it was found that GRI has proved to be an incentive for guiding the organization’s sustainability reporting. Even if the sector-specific standard/ guideline is considered a ceiling for sustainability reporting, the ceiling tends to be very high for the current performance of the organization.

Medarbetarsamtal har en betydelsefull roll och är vanligt förekommande på många svenska företag. Dessa samtal tillsammans med målstyrning ger möjligheten för både chef och medarbetare att skapa utvecklingsmöjligheter för verksamheten. Den bakomliggande orsaken till medarbetarsamtalens viktiga roll handlar om den rationella syn som finns kring dess effektivitet. Denna studie syftar till att undersöka funktionen av medarbetarsamtal och hur dessa fungerar i praktiken. Detta för att kunna identifiera de processer som uppstår på arbetsplatsen som kan förenas med fenomenet funktionell dumhet. Detta fenomen syftar till att individer inom en organisation gör de som förväntas av dem utan att reflektera kring sina arbetsuppgifter. Denna bristande reflektion och förståelse begränsar därmed utvecklingen av både verksamheten men också individen vilket därmed tyder på att man är funktionellt dum. Studien har för avsikt att ge förslag till både ledare och medarbetare kring hur målen på en arbetsplats bör utformas på ett hållbart samt relevant sätt. Då författarna ämnade att skapa en bild av respondenternas upplevelser ansågs en kvalitativ forskningsmetod vara mest passande. Datamaterialet består av totalt 16 semistrukturerade intervjuer med HR-anställda, chefer och medarbetare från fyra olika företag. Undersökningen av medarbetarsamtalets funktion och betydelse har gjorts bland respondenter där samtliga har varit verksamma i sin roll i minst tre år. Således finns en erfarenhet inom den roll som respondenten representerar samtidigt som denna tidsperiod ger indikationen att individen erfarit några medarbetarsamtal. Cheferna som har deltagit i studien har även ett medarbetaransvar på minst fem anställda samtidigt som de HR-anställda bedriver utveckling av dessa. Studiens resultat tyder sammanfattningsvis på att medarbetarsamtal har en betydelsefull roll på arbetsplatsen. Däremot identifieras flertalet processer som inte är genomtänkta för att i sin tur kunna gynna den enskilde medarbetaren men också verksamheten som helhet. Flertalet respondenter uttryckte hur de inte kunde identifiera sina målsättningar till verksamhetens visioner samtidigt som de inte heller fick vara med och utforma eller påverka dessa. De anställda som är med och påverkar sina egna mål kunde se sitt syfte med sin roll i förhållande till verksamhetens utveckling. Cheferna uttryckte även hur medarbetarsamtalen utformas utefter personliga preferenser samtidigt som de uppskattar visst stöd från HR-funktionen på arbetsplatsen. Bland slutsatserna som har presenterats framkommer det hur en tydlig handlingsplan bör prioriteras för att utveckla verksamhetens anställda. Ännu en slutsats är att det behöver skapas en grundläggande förståelse kring hur och varför målen är viktiga samt relevanta för den enskilda medarbetaren och verksamheten. Slutligen har vi konstaterat att hållbarheten kring målsättningar är att ha kontinuerliga uppföljningar med de anställda för att se till att målen är väsentliga. Genom att ha flera samtal om året ges även möjligheten att både snabbare och mer effektivt kunna fånga upp aspekter som välmående och personlig utveckling för den anställde. / Performance appraisals are common in many Swedish companies. These are conversations where the employee and manager talk about achievements and future goals for the employee. Together with goal management, these appraisals provide the chance for both the manager and employees to create development opportunities for the business. The underlying reason for the important role of performance appraisals is the rational view that exists around their effectiveness. This study aims to examine the function of performance appraisals and how these work in practice in order to identify processes that can be associated with the phenomenon functional stupidity. This phenomenon means that individuals within an organization do what is expected of them without reflecting on their tasks. This lack of reflection and understanding limits the development of both the organization but also the individual, which indicates functionally stupidity. The study intends to provide suggestions to both managers and employees on how the goals of a workplace can be designed in a sustainable and relevant way. A qualitative study was conducted, and a total of 16 semi-structured interviews with HR employees, managers and employees from four different companies were conducted. The results of the study indicate that performance appraisals have a significant role in the workplace. However, signs of functional stupidity are also identified. The respondents are well aware of processes that are not well thought out and do not benefit the individual employee nor the business as a whole. The majority of respondents expressed they could not relate their objectives to the business's visions, and at the same time they were not allowed to participate in designing or influencing them. The employees who are involved in influencing their own goals knew the purpose of their role in relation to the development of the business. The managers expressed how the performance appraisals are designed according to personal preferences, while at the same time appreciating some support from the HR function in designing the performance appraisals. Among the conclusions that have been presented, it appears that a clear action plan should be prioritized in order to support the development of employees. Another conclusion is that it is necessary to create a basic understanding of how and why the goal is important and relevant to the individual employee and the business. Finally, we found that continuous follow-ups with employees ensures that the goal-setting process is sustainable while aspects such as well-being and individual professional development are ensured at the same time.

No description available.

With the transition towards renewable energy, and the deregulation of the electricity market, generation patterns and grid topology are changing. These changes increase the need for transfer capacity. One limiting factor, which sometimes leads to underutilization of the transmission grid, is interarea oscillations. These system-wide modes involve groups of generators oscillating relative to each other and are sometimes hard to control due to their scale and complexity. In this thesis we investigate how high-voltage direct current (HVDC) transmission can be used to attenuate interarea oscillations. The thesis has two main contributions. In the first contribution we show how the stability of two asynchronous grids can be improved by modulating the active power of a single interconnecting HVDC link. One concern with modulating HVDC active power is that the interaction between interarea modes of the two grids may have a negative impact on system stability. By studying the controllability Gramian, we show that it is always possible to improve the damping in both grids as long as the frequencies of their interarea modes are not too close. For simplified models, it is explicitly shown how the controllability, and therefore the achievable damping improvements, deteriorates as the frequency difference becomes small. The second contribution of the thesis is to show how coordinated control of two (or more) links can be used to avoid interaction between troublesome interarea modes. We investigate the performance of some multivariable control designs. In particular we look at input usage as well as robustness to measurement, communication, and actuator failures. Suitable controllers are thereby characterized. / Övergången till förnybar energi och avregleringen av elmarknaden leder till förändrade produktions-och överföringsmönster. Dessa förändringar medför behov av en ökad överföringskapacitet. En begränsande faktor, som kan leda till ett underutnyttjande av stamnätet, är interareapendlingar. Dessa systemövergripande pendlingar involverar grupper av generatorer som svänger i förhållande till varandra. Interareapendlingar är ibland svåra att styra på grund av deras skala och komplexitet. I denna avhandling undersöker vi hur förbindelser med högspänd likström, engleska high-voltage direct current (HVDC), kan användas för att dämpa interareapendlingar. Avhandlingen har två huvudbidrag. I det första bidraget visar vi hur stabiliteten hos två olika synkrona nät kan förbättras genom att modulera den aktiva effekten hos en enda HVDC-länk. Ett bekymmer med aktiv effektmodulering är att växelverkan mellan interareapendlingar hos de två näten kan ha en negativ inverkan på systemets stabilitet. Genom att studera styrbarhetsgramianen visar vi att det alltid är möjligt att förbättra dämpningen i båda näten så länge som frekvenserna hos deras interareapendlingar inte ligger för nära varandra. För förenklade modeller visas det uttryckligen hur styrbarheten och därmed de möjliga dämpningsförbättringarna, försämras då frekvensskillnaden blir liten. Avhandlings andra bidrag visar hur koordinerad styrning av två (eller fler) länkar kan användas för att undvika växelverkan mellan besvärliga interareapendlingar. Vi undersöker prestandan hos olika typer av flervariabla regulatorer. I synnerhet undersökers styrsignalsanvändning samt robusthet mot mät-, kommunikations- och aktuatorfel. Därigenom karakteriseras lämpliga regulatortyper. / <p>QC 20190308</p>

Quantum information technologies include secure quantum communications and ultra precise quantum sensing that are significantly more efficient than their classical counterparts. To enable such technologies, we need a scalable quantum platform in which qubits are con trollable. Color centers provide controllable optically-active spin qubits within the coherence time limit. Moreover, the nearby nuclear spins have long coherence times suitable for quantum memories. In this thesis, I present a theoretical understanding of and control protocols for various color centers. Using group theory, I explore the wave functions and laser pumping-induced dynamics of VSi color centers in silicon carbide. I also provide dynamical decoupling-based high-fidelity control of nuclear spins around the color center. I also present a control technique that combines holonomic control and dynamically corrected control to tolerate simultaneous errors from various sources. The work described here includes a theoretical understanding and control techniques of color center spin qubits and nuclear spin quantum memories, as well as a new platform-independent control formalism towards robust qubit control. / Doctor of Philosophy / Quantum information technologies promise to offer efficient computations of certain algorithms and secure communications beyond the reach of their classical counterparts. To achieve such technologies, we must find a suitable quantum platform to manipulate the quantum information units (qubits). Color centers host spin qubits that can enable such technologies. However, it is challenging due to our incomplete understanding of their physical properties and, more importantly, the controllability and scalability of such spin qubits. In this thesis, I present a theoretical understanding of and control protocols for various color centers. By using group theory that describes the symmetry of color centers, I give a phenomenological model of spin qubit dynamics under optical control of VSi color centers in silicon carbide. I also provide an improved technique for controlling nuclear spin qubits with higher precision. Moreover, I propose a new qubit control technique that combines two methods - holonomic control and dynamical corrected control - to provide further robust qubit control in the presence of multiple noise sources. The works in this thesis provide knowledge of color center spin qubits and concrete control methods towards quantum information technologies with color center spin qubits.

The DC-side floating capacitors in the floating power modules of power converters are subject to high voltage fluctuation, due to the presence of reactive harmonic components. Utilizing passive capacitors, as done in traditional methods, helps reduce the DC-bus voltage ripple but makes the system bulky. An active capacitor can be integrated with the floating H-bridge power modules to remove the effect of the ripple powers on the DC bus. The auxiliary circuit, which is much smaller in size compared to an equivalent passive capacitor, helps increase the power density of the system. This work focuses on the analysis of power components, and the extension of the active capacitor to the Perturbation Injection Unit (PIU), in which the DC side is highly distorted by multiple harmonic components. A control scheme is proposed to compensate for these multiple harmonics and balance the DC-link voltage in the active capacitor. Also, an equivalent DC-bus impedance model is introduced, which is more accurate than that in existing works. Simulation studies and evaluation of the design have verified the effectiveness of the active capacitor solution. / Single-phase power converters have been widely used in many applications such as electric vehicles, photovoltaic (PV) systems, and grid integration. Due to their popular application, there is a need to reduce the sizes and volumes while still maintaining good performances of the systems. One of the most effective methods, which is a subject in many research works, is to replace the bulky passive capacitor bank in a system by an active capacitor. The active capacitor is designed to absorb the ripple components in the DC side of the converters, which results in a constant DC-link voltage. In comparison to the passive capacitor solution, the active capacitor is much smaller in size but can give a better DC-bus ripple performance. Therefore, the active capacitor has become an attractive solution for the single-phase converters. The active capacitor for the traditional rectifier, where the DC side is directly connected to a load, has been intensively investigated in the past decade. However, there is limited research regarding the active capacitor for rectifiers with floating H-bridge power modules. This work extends the application of the active capacitor to the Perturbation Injection Unit (PIU), which is a grid-connected single-phase rectifier with floating H-bridge power modules. The selection of a suitable active capacitor for the PIU is based on the evaluation of various active capacitor banks. Limits in existing control schemes, which prevent the extension of the active capacitor to the PIU, are thoroughly studied. An effective voltage-mode control scheme is then proposed for the selected active capacitor, which makes it an attractive solution for the PIU. Moreover, limits of the DC-bus impedance analysis using traditional assumptions in existing works are investigated, and an improved DC-bus impedance model is proposed. Based on the operation conditions of the PIU and the proposed impedance model, the active capacitor's components can be properly designed, and improved configurations in terms of the equivalent impedance can be analyzed. Simulation results, as well as the design and evaluation of the active capacitor, demonstrate great improvements in terms of volume and weight over the traditional passive capacitor bank.