Amplitude-versus-offset, AVO, approximations allow the estimation of various properties from pre-stack seismic gathers. Recently it has been suggested that fluid mobility is a controlling factor in pore pressure equalisation and can result in anomalous velocity dispersion in the seismic bandwidth. However, current approximations all assume an elastic subsurface and are unable to account for velocity dispersion. I have applied existing methodologies to a real dataset to qualitatively detect and interpret spectral amplitude anomalies. Three areas had AVO and spectral signature consistent with frequency-dependent AVO theory. The results suggest that it is feasible to measure such effects on real data in the presence of random noise. It would imply that the relaxation parameter, tau, is larger in the field than has been measured in water-saturated real and synthetic sandstones in the laboratory. I extended a two-term AVO approximation by accounting for velocity dispersion and showed how the resultant reflection coefficient becomes frequency-dependent. I then used this to measure P- and S-wave reflectivity dispersion using spectrally-balanced amplitudes. The inversion was able to quantify the affect of the P-wave velocity dispersion as an instantaneous effect on the reflection. NMO stretch was an issue at the far offsets and I limited myself to the near offsets and effectively measured only the P-wave reflectivity dispersion. I showed how the P-wave reflectivity dispersion signs depend on the AVO classification of the reflection whilst the magnitude depends on the crack density of my model. I showed how the effect of noise and thin-bed tuning can enter uncertainties into the interpretation of spectral anomalies. Whilst it is possible to detect frequency-dependent AVO signatures on pre-stack gathers, the interpretation remains non-unique. I have quantitatively measured a new physical property, reflectivity dispersion, from pre-stack seismic data. I have presented a method of detecting and measuring velocity dispersion in pre-stack gathers but there remain ambiguities in the interpretation of such results. The approach incorporates spectrally decomposed data in an extended AVO inversion scheme. Future work should investigate the application of the methodology to a real seismic dataset.

Greenhouse gasses, such as carbon dioxide and methane absorb and emit heat radiation, which contribute to global warming. Human activities such as increased emissions through burning of fossil fuels and deforestation drive this climate threat. International treaties such as the Paris agreement, enables stakeholders to mitigate effects of climate impact and create new sustainable markets. Various carbon offset projects on the voluntary market are an attempt to neutralize climate impact. In this report we identify five main project types for carbon offsets: i) forestry and land use, ii) renewable energy and energy effectivization, iii) transport, iv) waste handling and v) household devices. These project types are evaluated against UNs 17 sustainable development goals. The results show a net positive impact on goal 13, Climate action, for all project types, which is congruent with the focus on carbon offsetting. The results also show that impact varies depending on how the project is deigned. Climate offsetting has enabled multiple stakeholders to contribute to climate change mitigation. Despite many global benefits, carbon offsets have been subject to criticism in cases where the concept is not used as intended. There are currently no clear guidelines as to when focus for companies should shift from internal reduction to external reduction through offsetting. Validation of carbon offsets is another problematic aspect, as there is no one standard for the market to secure the quality of projects.

Cette thèse porte sur le marché dit « volontaire » des services de compensation carbone. Sur ce marché, des entreprises, qui n’ont aucune obligation de souscrire à ces services, achètent à des opérateurs privés, ONG ou entreprises, des « crédits carbone » pour « compenser » leurs émissions de gaz à effet de serre (GES). Pour obtenir ces crédits carbone, les opérateurs du marché mettent en œuvre des projets de réduction des émissions de GES dans les pays du Sud. Ces nouveaux échanges marchands du début des années 2000 ne sont pas sans susciter de critiques. Journalistes, ONG environnementales et scientifiques considèrent que ce marché, d’une part, ne permet pas de réduire efficacement les émissions de GES et, d’autre part, que les populations du Sud encourent de potentiels dangers avec la mise en œuvre de tels projets. La thèse interroge ainsi l’apparent paradoxe du choix des entreprises d’investir dans des services environnementaux contestés alors que ces derniers ne constituent pas une obligation réglementaire et peuvent mettre en danger leur réputation. En considérant le marché « volontaire » comme un « marché contesté », selon le sens donné à cette notion par Steiner et Trespeuch (2014), la thèse rend compte des conditions d’existence et de maintien de ce marché. A partir d’entretiens, d’observations et de l’analyse de sources écrites, elle examine le rôle de divers dispositifs, du travail marchand ainsi que de l’appropriation de l’offre par les acheteurs dans l’organisation de ce marché. La thèse interroge plus généralement le rapport entre économie et environnement et s’intéresse aux ressorts de l’engagement « volontaire » des entreprises pour le climat. / This dissertation deals with the so-called “voluntary” carbon offset market. In this market, companies, which have no obligation to subscribe to these services, purchase “carbon credits” to “offset” their greenhouse gas (GHG) emissions from private operators (NGOs or businesses). To obtain carbon credits, operators implement GHG emission reduction projects in Southern countries. These new trade exchanges, which date from the early 2000s, provoke critics. Journalists, environmental NGOs and scientists believe that this market on the one hand does not effectively reduce GHG emissions to fight against climate change, and on the other hand that people in the South face potential dangers linked to the implementation of carbon offsetting projects. The dissertation thus questions the apparent paradox of the choice of companies to invest in contested environmental services when they are not a regulatory obligation and may endanger their reputation. By considering the “voluntary” market as a “contested market”, according to the meaning given to this notion by Steiner and Trespeuch (2014), the dissertation explores the conditions of existence and maintenance of this market. Through interviews, observations and written sources, our research analyzes the role of various market devices, but also commercial work as well as the appropriation of the offer by buyers in organizing this market. In doing so, it questions more generally the relationship between economy and the environment and is interested in the determinant factors of the “voluntary” commitment of companies for the fight against global warming.

This thesis presents a novel method to solve the problem of estimating the carrier frequency set in an Orthogonal Frequency Division Multiplexing (OFDM) system. The approach is based on the minimization of the probability of symbol error. Hence, this approach is called the Minimum Symbol Error Rate (MSER) approach. An existing approach based on Maximum Likelihood (ML) is chosen to benchmark the performance of the MSER-based algorithm. The MSER approach is computationally intensive. The thesis evaluates the approximations that can be made to the MSER-based objective function to make the computation tractable. A modified gradient function based on the MSER objective is developed which provides better performance characteristics than the ML-based estimator. The estimates produced by the MSER approach exhibit lower Mean Squared Error compared to the ML benchmark. The performance of MSER-based estimator is simulated with Quaternary Phase Shift Keying (QPSK) symbols, but the algorithm presented is applicable to all complex symbol constellations.

Cette thèse est un des premiers travaux sur les transistors bipolaires à hétérojonction (TBH)de la filière InP ayant une base en GaAsSb. Une méthode de mesure précise des offsets des<br />hétérojonctions de type II par électroluminescence, associée aux mesures électriques a permis de clarifier les conditions du transport électronique dans le système InP/GaAsSb et d'initier l'utilisation d'un émetteur en InGaAlAs. Deux briques technologiques spécifiques ont été développées : la gravure chimique sélective de InGaAlAs par rapport à GaAsSb et la réalisation de contacts ohmiques très faiblement résistifs sur p-GaAsSb. Ceci a permis l'assemblage d'un procédé de fabrication de TBH ultra-rapides dans cette filière. La faisabilité de ce procédé a été démontrée par la réalisation de TBH submicroniques ayant des fréquences ( fT ; fmax) de (155 ; 162) GHz. Son optimisation, protégée par deux brevets, montre des perspectives pour atteindre des fréquences ( fT ; fmax) de (380 ; 420) GHz.

Le sujet de cette thèse s'inscrit dans le cadre des systèmes tolérants aux défauts sous contraintes avec prise en considération de la dégradation des performances. L'objectif principal de ce travail consiste à considérer la gestion des références comme une partie intégrante du système de commande tolérant aux défauts. Dans la littérature, la plupart des méthodes actives de tolérance aux défauts supposent que le recouvrement du système nominal est toujours possible et que les performances nominales sont toujours atteignables. Cette condition est peu réaliste dans la pratique puisque plusieurs éléments empêchent le système reconfiguré de revenir à son mode de fonctionnement nominal. Dans le domaine industriel, l'ensemble des contraintes du système est un handicap majeur qui limite le fonctionnement nominal d'un système à des plages fonctionnelles bien définies. Ces plages fonctionnelles sont énormément réduites après l'apparition de certains défauts dits sévères et qui affectent généralement les actionneurs. Par conséquent, cette hypothèse de recouvrement des performances nominales dans le cas des systèmes sous contraintes limite l'ensemble des défauts traités par ces méthodes classiques à quelques défauts dits mineurs. Afin de remédier a ce problème, une architecture de reconfiguration structurée en deux niveaux est proposée. Le premier concerne les algorithmes classiques de reconfiguration en agissant sur un contrôleur reconfigurable, et le deuxième agit sur le module de gestion des références conçu à base d'un gouverneur de référence avec offset. La connaissance exacte du modèle en post-défaut nécessite un système de détection et diagnostic de défaut qui permet d'estimer l'amplitude de défaut, ce qui conduit à la synthèse d'un observateur adaptatif d'estimation de défaut à base de LMI. Afin de synchroniser le déroulement du processus FTC, deux indices ont été conçus. Le premier indice porte sur le mécanisme de décision permettant de sélectionner le/les niveau(x) de reconfiguration nécessaire(s) à l'accommodation du défaut. Le deuxième indice permet d'évaluer le niveau de dégradation du système " post-défaut ". Une dégradation de performance est toujours admise tant que les consignes de sécurité sont respectées.

<p>Stora Enso är ett integrerat pappers-, paketerings- och skogsföretag som producerar finpapper, kartong samt träprodukter. Denna studie har genomförts på uppdrag av Stora Enso och utvärderar samt utreder existerande korrelationer mellan olika kvalitetsparametrar samt upplevd bildkvalitet. Det är oklart vad som påverkar den upplevda bildkvaliteten i störst utsträckning och Stora Enso ville därmed få ökad kunskap angående vilka kvalitetsparametrar som resulterar i ett gott tryckresultat. I och med digitalpressarnas utveckling introduceras papperskvaliteter med varierande egenskaper på marknaden och Stora Enso vill erhålla kunskap angående olika papperskvaliteters prestationer kvalitetsmässigt vid tryckning i olika tryckpressar. </p><p>I denna studie baserades mätningarna och analyserna, tryck- och papperstekniska samt subjektiva, på elva olika papperskvaliteter tryckta i tre tryckpressar, DC2060, iGen3 samt offset. Rapporten redovisar resultat för respektive press- och papperskombinations prestationer och eventuella korrelationer med upplevd bildkvalitet kartläggs. </p><p>Studien har visat att tryckresultatet på obestrukna papperskvaliteter påverkas av ett flertal parametrar. Mätvärden för densitet, tryckglans, färgomfångsvolym samt färgkvalitet i fulltonsytor korrelerar väl med den upplevda bildkvaliteten. Vid tryckning av obestrukna papperskvaliteter är det viktigt att välja en papperskvalitet med önskade egenskaper för tryckningen i fråga. Studien påvisar att flammighet, jämnhet i tryck samt glansvariationer inte påverkar utvärderingen av tryckresultatet vid en visuell bedömning. För bestrukna papperskvaliteter korrelerar inte några mättekniska parametrar med det upplevda bildkvalitetsresultatet på ett tydligt sätt. Detta tyder på att oavsett vilken bestruken papperskvalitet som används vid tryckning i DC2060, iGen3 eller offset så erhålls liknande tryckresultat. Detta är anmärkningsvärt då priserna på bestrukna papperskvaliteter varierar kraftigt. </p><p>De papperstekniska parametrar som verkar påverka det upplevda tryckresultatet på både obestrukna och bestrukna papperskvaliteter är först och främst papprets ytråhet samt vithet. Dessa parametrar påverkar tillsammans färgomfånget, som i sin tur påverkar färgkvaliteten i tryck. Densiteten och tryckglansen påverkas av papperets ytråhet och det var därmed inte oväntat att ytråheten och vitheten också skulle påverka den upplevda bildkvaliteten. </p><p>När det gäller pressarnas prestationer blev resultatet att iGen3 gav ett tryckresultat, oavsett papperskvalitet, som var mycket jämnt. Det kunde därmed konstateras att tryckpressen är mycket okänslig för val av papperskvalitet. DC2060 erhöll mycket höga värden för exempelvis densitet, tryckglans och färgomfångsvolym. Det förekom dock små variationer i tryckresultat. Tryckningar utförda i offset erhöll mycket låga flammighetsstörningar och låg ojämnhet i tryck. På bestrukna papperskvaliteter gav DC2060 och offset färre variationer i tryckresultat än på obestrukna papperskvaliteter.</p>

Advances toward increased integration and complexity of radio frequency (RF) andmixed-signal integrated circuits reduce the effectiveness of contemporary testmethodologies and result in a rising cost of testing. The focus in this research is on thecircuit-level implementation of alternative test strategies for integrated wirelesstransceivers with the aim to lower test cost by eliminating the need for expensive RFequipment during production testing.The first circuit proposed in this thesis closes the signal path between the transmitterand receiver sections of integrated transceivers in test mode for bit error rate analysis atlow frequencies. Furthermore, the output power of this on-chip loopback block wasmade variable with the goal to allow gain and 1-dB compression point determination forthe RF front-end circuits with on-chip power detectors. The loopback block is intendedfor transceivers operating in the 1.9-2.4GHz range and it can compensate for transmitterreceiveroffset frequency differences from 40MHz to 200MHz. The measuredattenuation range of the 0.052mm2 loopback circuit in 0.13µm CMOS technology was 26-41dB with continuous control, but post-layout simulation results indicate that theattenuation range can be reduced to 11-27dB via optimizations.Another circuit presented in this thesis is a current generator for built-in testing ofimpedance-matched RF front-end circuits with current injection. Since this circuit hashigh output impedance (>1k up to 2.4GHz), it does not influence the input matchingnetwork of the low-noise amplifier (LNA) under test. A major advantage of the currentinjection method over the typical voltage-mode approach is that the built-in test canexpose fabrication defects in components of the matching network in addition to on-chipdevices. The current generator was employed together with two power detectors in arealization of a built-in test for a LNA with 14% layout area overhead in 0.13µm CMOStechnology (<1.5% for the 0.002mm2 current generator). The post-layout simulationresults showed that the LNA gain (S21) estimation with the external matching networkwas within 3.5% of the actual gain in the presence of process-voltage-temperaturevariations and power detector imprecision.

The aim for this thesis was to develop a proposal of documentation, containing rules and procedures, which JernströmOffset needs to acquire the Certified Graphic Production certification. A fundamental part was to study the materialissued by Sveriges Grafiska Mediaförening, to clarify the requirements that must be met to obtain the certification. Therecommendations found in the CGP material must also be considered.Based on the requirements and recommendations of Certified Graphic Production, a mapping of the workflows atJernström Offset was performed. It was done by interviewing employees from different departments at the company,this to get a clear understanding of the operations carried out throughout the production flow and the final qualityfollow-up.During our reviewing process we found that a number of changes, in terms of working environment and practices,must be made at the company. As a result of this we propose some appropriate actions to be implemented.The documentation was finally written, through the requirements and recommendations of Certified GraphicProduction and then applied to Jernström Offset’s work procedures.

One of the challenges of distributed cooperative orthogonal frequency division multiplexing systems is that the multiple carrier frequency offsets (CFOs) simultaneously present at the receiver. According to our knowledge up to now, even the CFOs are known at the receiver, the way to perfectly eliminate the effect of CFOs is still an open problem. This thesis proposes a scheme to mitigate the effect due to multiple CFOs by using the concept of intercarrier interference self-cancellation in transitional OFDM systems, a scheme where the data are simultaneously modulated on symmetric subcarriers between two transmit antennas. Before processing FFT, two values related to CFOs are used to adjust the time-domain signal resulting in better signal-to-interference ratio in even and odd subcarriers respectively. After that, the data are combined by applying maximum ratio combining and then decoded. Simulation results are given to demonstrate the effectiveness of the proposed scheme as compared to previous scheme.