No description available.

This thesis addresses two fundamental topics in Engineering Seismology; the application of Probabilistic Seismic Hazard Analysis (PSHA) methodology, and the estimation of measures of Strong Ground Motion. These two topics, while being related, are presented as separate sections. In the first section, state-of-the-art PSHA methodologies are applied to various sites in the Buller Region, South Island, New Zealand. These sites are deemed critical to the maintenance of economic stability in the region. A fault-source based seismicity model is developed for the region that is consistent with the governing tectonic loading, and seismic moment release of the region. In attempting to ensure this consistency the apparent anomaly between the rates of activity dictated by deformation throughout the Quaternary, and rates of activity dictated by observed seismicity is addressed. Individual fault source activity is determined following the application of a Bayesian Inference procedure in which observed earthquake events are attributed to causative faults in the study region. The activity of fault sources, in general, is assumed to be governed by bounded power law behaviour. An exception is made for the Alpine Fault which is modelled as a purely characteristic source. The calculation of rates of exceedance of various ground motion indices is made using a combination of Poissonian and time-dependent earthquake occurrence models. The various ground motion indices for which rates of exceedance are determined include peak ground acceleration, ordinates of 5% damped Spectral Acceleration, and Arias Intensity. The total hazard determined for each of these ground motion measures is decomposed using a four dimensional disaggregation procedure. From this disaggregation procedure, design earthquake scenarios are specified for the sites that are considered. The second part of the thesis is concerned with the estimation of ground motion measures that are more informative than the existing scalar measures that are available for use in New Zealand. Models are developed for the prediction of Fourier Amplitude Spectra (FAS) as well as Arias Intensity for use in the New Zealand environment. The FAS model can be used to generate ground motion time histories for use in structural and geotechnical analyses. Arias Intensity has been shown to be an important strong motion measure due to its positive correlation with damage in short period structures as well as its utility in predicting the onset of liquefaction and landslides. The models are based upon the analysis of a dataset of New Zealand Strong Motion records as well as supplementary near field records from major overseas events. While the two measures of ground motion intensity are strongly related, different methods have been adopted in order to develop the models. As part of the methodology used for the FAS model, Monte Carlo simulation coupled with a simple ray tracing procedure is employed to estimate source spectra from various New Zealand earthquakes and, consequently, a magnitude - corner-frequency relationship is obtained. In general, the parameters of the predictive equations are determined using the most state-of-the-art mixed effects regression procedures.

Prior immunity to a related or unrelated pathogen greatly influences the host’s immune response to a subsequent infection and can cause a dramatic difference in disease course, a phenomenon known as heterologous immunity. Heterologous immunity can influence protective immunity, immunopathology and/or immune deviation of cytokine-producing T cell subsets. Examples of heterologous immunity have been well documented in mouse models, as well as during human infections. For example, prior immunity to lymphocytic choriomeningitis virus (LCMV) provides partial protection against vaccinia virus (VV), as LCMV-immune mice show reduced VV titers and increased survival upon lethal dose VV infection. Heterologous protection against VV challenge, as a result of LCMV immunity, is mediated by LCMV-specific CD4 and CD8 T cells, as transfer of LCMV-specific memory T cells can mediate this protective effect in naïve mice. The recognition of a single TCR with more than one MHC-peptide complex is referred to as T cell cross-reactivity. A VV Kb-restricted epitope a11r198 was identified to be able to induce cross-reactive responses from LCMV-specific CD8 T cells. During VV infection, LCMV-specific memory T cells that are cross-reactive to VV epitopes produce IFN-γ early in VV infection. IFN-γ is essential for mediating the protection against VV in LCMV-immune mice, as this heterologous protection is absent in IFN-γR-/-and IFN-γ blocking antibody-treated LCMV-immune mice. In addition to protective immunity, cross-reactive LCMV-specific memory T cells and IFN-γ also induce an altered immunopathology during heterologous VV challenge. LCMV-immune mice show moderate to severe levels of inflammation of the fat tissue, known as panniculitis, in the visceral fat pads upon VV challenge. In humans, panniculitis is a painful condition, most commonly presenting as erythema nodosum. Erythema nodosum is a disease of unknown etiology with no known treatment. It may occur following intracellular bacterial and viral infections, and occasionally happens after vaccination with VV for smallpox. During infections there can be a delicate balance between the ability of immune responses to provide protective immunity, and the tendency to induce immunopathology. By using the mouse model of heterologous immunity between LCMV and VV, we tried to understand how the immunity to LCMV biased the balance between the protective immunity and immunopathology, and what effector molecules were responsible for the pathogenesis of panniculitis in this system. TNF is a pleiotropic cytokine, which is required for normal innate and adaptive immune responses. Its functions range from inducing proliferative responses including cell survival, to destructive responses such as promoting apoptosis and programmed necrosis. In response to inflammatory stimuli, activated macrophages/ monocytes produce large amounts of TNF, and upon activation, T cells, B cells and NK cells also produce TNF. In vitro and in vivo studies have shown that TNF in synergy with IFN-γ plays an important role in mediating host defense against pathogens, such as Listeria monocytogenesand poxviruses in mice and hepatitis B virus and human immunodeficiency virus in humans. However, inappropriate expression of TNF often results in tissue damage. Considering the important role TNF plays in both host defense and mediating autoimmune diseases, we hypothesized that TNF was required for mediating both protective and pathogenic effects in the heterologous immunity between LCMV and VV. We first examined whether TNF was involved in mediating protective heterologous immunity. LCMV-immune mice, that were TNF-deficient as a consequence of genetic deletion (TNF-/-) or receptor blockade by treatment with etanercept (TNFR2: Fc fusion protein), were challenged with VV. These TNF-deficient mice showed normal recruitment and selective expansion of cross-reactive LCMV-specific memory CD8 T cells. They also exhibited efficient clearance of VV similar to LCMV-immune mice with normal TNF function. Thus, we concluded that neither TNF nor lymphotoxin (LT), which uses the same receptors as TNF, was required in mediating protective heterologous immunity against VV. Indeed, prior immunity to LCMV could completely compensate for the role of TNF in protection of naïve mice against VV infection, even under conditions of lethal dose inoculum. Thus, heterologous immunity may help explain why treatment of humans with etanercept is reasonably well tolerated with relatively few infectious complications. One of the histological characteristics of panniculitis is necrosis of adipose tissue. It is known that three members in the TNF superfamily, i.e. TNF/LT, FasL and TRAIL are able to induce necrosis of a target cell. It is also known that TNF is able to induce VV-infected cells to go through necrosis, when apoptosis is blocked in these cells by VV protein. Furthermore, TNF and FasL have already been shown to be associated with some skin and fat pathology. Thus, we hypothesized that TNF, FasL and TRAIL were involved in the pathogenesis of panniculitis in VV infected LCMV-immune mice. By using blocking antibodies or genetically deficient mice, we demonstrated that both TNF/LT and FasL were crucial for inducing panniculitis. Although TNFR1 has been reported to induce programmed necrosis, our data indicated that TNFR2, not TNFR1, was involved in mediating tissue damage in the fat pads of LCMV-immune mice infected with VV. We also found that TNF signaled through TNFR2 to up-regulate the expression of Fas on adipocytes. Thus, the engagement of Fas on the adipocytes with FasL expressed on activated VV-specific and cross-reactive LCMV-specific CD8 T cells in the fat pads could lead to panniculitis. Thus, our data may identify a potential mechanism in the pathogenesis of human panniculitis, and may suggest a possible treatment for this painful disease. Recent reports suggest that heterologous immunity may contribute to the tremendous variation in symptoms between individuals, from subclinical to death, upon viral infection. Even in genetically identical mice, variations in immunopathology from none to life-threatening levels of pathology are observed in LCMV-immune mice during VV infection. By adoptive transfer of splenocytes from a single LCMV-immune donor into two recipients, we showed that similar levels of pathology were generated in mice receiving the same splenocytes. However, the level of pathology varied among recipients receiving splenocytes from different LCMV-immune donors. The difference in levels of VV-induced pathology observed in individual LCMV-immune mice was a reflection of the private specificity of the T cell repertoire, which is a unique characteristic of each individual immune host. The goal of this doctoral thesis is to understand how heterologous immunity contributes to the pathogenesis of panniculitis. Our data demonstrate that TNF/LT and FasL directly contribute to development of panniculitis in LCMV-immune mice during VV infection, and suggest that anti-TNF treatment might be a useful treatment for diseases, such as erythema nodosum and lupus-induced acute fatty necrosis in humans.

The aim of the master thesis is to sum up theoretical information about beamforming methods of microphone arrays and to verify their functionality. At the beginning of this work there are simulated different varietes of linear uniform and nonuniform microphone arrays and circular arrays. The results are verificated by a practical measurement in ideal conditions. Then I will focuse on implementation of the DAS(Delay And Sum), SAB(Sub Array Beamforming), CDB(Constant Directivity Beamforming), CDB-CA(CDB-Circular Arrays) beamformer including theoretical and practical verification of the functionality in ideal conditions. At the end of this thesis are all beamforming methods compared with each other at SNR(signal to Noise Ratio) and directivity parameters.

In der vorliegenden Arbeit wird eine prädiktive Fahrstrategie vorgestellt, die auf Basis von Ampel-Fahrzeug-Kommunikationsdaten generiert wird. Dazu wird ein aktueller Ansatz für eine prädiktive Fahrstrategie zur Annäherung an eine Lichtsignalanlage (LSA) untersucht. Es werden verschiedene Optimierungsansätze deutlich, von denen ein großer Teil bei der Systemerweiterung berücksichtigt wird. Bei der Analyse konnte gezeigt werden, dass die bisherige Strategieempfehlung durch den Einfluss vorausfahrender Verkehrsteilnehmer eingeschränkt wird. Es ergaben sich potentielle Problemsituationen, welche sich im realen Straßenverkehr negativ auf die Funktionalität des Fahrerassistenzsystems (FAS) auswirken. Für Anfragen des Öffentlichen Personen Nachverkehrs (ÖPNV) wurde ermittelt, dass keine allgemeingültigen Aussagen über die Eignung der Assistenzfunktion gegeben werden können. Die wesentliche Neuerung zu bisheriger Strategieansätze für die Annäherung an Knotenpunkte mit LSA ist die Berücksichtigung anderer Verkehrsteilnehmer. Dazu werden die neuen Größen effektive Freigabezeit und virtuelle Position der Haltelinie eingeführt, auf Basis derer die Strategieempfehlung des FAS an die Anzahl wartender Fahrzeug angepasst wird. Zur Untersuchung des möglichen Energieeinsparpotentials durch den Einsatz eines FAS wurde ein Simulationsmodell in MATLAB/SIMULINK entwickelt. Mit dessen Hilfe konnten verschiedene Situationen dargestellt werden, an denen der Einfluss der Funkreichweite sowie die Auswirkungen der Warteschlange auf das FAS verdeutlicht werden. Ferner kann der positive Effekt auf den Kraftstoffverbrauch und die Haltezeit an der LSA bestätigt werden. Das Simulationsmodell stellt eine gute Grundlage für weiterführende Untersuchung dar und kann an unterschiedliche Situationen angepasst werden. Um den Nutzen auch praktisch zu verifizieren wird eine Reihe von Fahrversuchen durchgeführt. Dem Fahrer wird dabei die Strategie in einem Display visualisiert. Für Situationen, in denen der Fahrzeugstillstand vermeidbar ist erhält dieser eine Geschwindigkeitsempfehlung. Ist ein Stillstand nicht vermeidbar, so erfolgt unmittelbar vor der Haltelinie, die Ausgabe der Restlaufzeit der Rotphase. Bei der Versuchsauswertung wird das Einsparpotential deutlich. Durch eine entwickelte GUI wird dem Fahrer eine Strategie auf dem Display visualisiert. Innerhalb mehrerer Versuchsfahrten konnten das FAS erprobt und in der anschließenden Versuchsauswertung klar die Verbesserungen aufgezeigt werden.:Abkürzungsverzeichnis Symbolverzeichnis 1 Einleitung 1.1 Motivation 1.2 Zielsetzung der Arbeit 1.3 Aufbau der Arbeit 2 Stand der Technik 2.1 System Fahrer-Fahrzeug-Verkehr 2.2 Fahrerassistenzsysteme 2.2.1 Klassifizierung nach Art der Fahrerunterstützung 2.2.2 Klassifizierung nach Fahraufgabenebene 2.2.3 Prädiktive Fahrerassistenzsysteme 2.2.4 Kreuzungsassistenz 2.3 Kooperative Systeme 2.3.1 Forschungsaktivitäten in Europa 2.3.2 Fahrerassistenzsysteme zur Reduktion der Fahrzeugemissionen 2.4 Berechnung des Kraftstoffverbrauches 2.5 Positionsbestimmung im Strassenverkehr 2.5.1 Aufbau eines Satellitennavigationssystems 2.5.2 Ablauf einer Positionsbestimmung 2.5.3 Fehlerquellen und Ursachen bei der Positionsbestimmung 2.5.4 Genauigkeit der Positionsbestimmung 2.5.5 Verarbeitung der Positionsdaten 2.6 Lichtsignalanlagen (LSA) 2.6.1 Definition wichtiger Begriffe 2.6.2 Überblick über Steuerungsverfahren 2.6.3 Umschaltung zwischen Signalprogrammen 2.6.4 Bevorrechtigungsarten für den ÖPNV 3 Analyse des bestehenden Systems 3.1 Fahrprofile zur Annäherung an LSA 3.2 Nutzen des Assistenzsystems 3.3 Ausgangslage des bisherigen Fahrerassistenzsystems 3.3.1 Phasenzyklus 3.3.2 Fahrzeugortung 3.3.3 Kommunikationsdaten des Ampelmoduls 3.3.4 Strategieansatz 3.4 Analyse der Strategieempfehlung 3.5 Optimierungsansätze 4 Erweiterter Systementwurf 4.1 Rahmenbedingungen und Vorgaben 4.2 Entscheidungssystem 4.3 Einfluss von Fahrzeugkolonnen 4.4 Effektive Freigabezeit und Rückstaulänge 4.5 Untersuchung der Geschwindigkeitsregelgrenzen 4.6 ÖPNV - Umgang mit dynamischen Signallaufzeiten 4.7 Ermittlung einer Fahrstrategie 4.8 Zusammenfassung der Optimierung 5 Simulative Untersuchung 5.1 Longitudinalmodell - Intelligent Driver Model – IDM 5.2 Modell zur Schätzung des Kraftstoffverbrauches 5.3 Aufbau des SIMULINK-Modells 5.4 Parametervariation und Ergebnisse 5.4.1 Rahmenbedingungen und Vorgaben 5.4.2 Einfluss der Funkreichweite 5.4.3 Einfluss der Pulklänge 5.5 Zusammenfassung 6 Experimentelle Untersuchung 6.1 Versuchsaufbau 6.2 Mensch Maschine Schnittstelle 6.3 Programmstruktur 6.4 Versuchsdurchführung 6.5 Ergebnis und Zusammenfassung 7 Zusammenfassung und Ausblick A Abbildungsverzeichnis B Tabellenverzeichnis C Literaturverzeichnis D Anhang / In this paper a predictive driving strategy is presented, which is generated based on car to infrastructure communication data. An actual approach for a driver assistance system has been analyzed to identify room for improvements. The additional benefit of the presented work is the consideration of other road users driving ahead of the ego-vehicle in the process of finding the optimal speed for approaching the traffic-light. A MATLAB/SIMULINK model has been developed, which allows the simulation of different traffic situations to investigate the fuel consumption benefit of a vehicle equipped with the considered system. It illustrates the influence of the radio range and the length of the queue in front of the stop line. Furthermore the positive effect to the fuel consumption of the developed system could be evaluated. The simulation model is a good basis for further tests and could be easily adapted to various situations and vehicles. In addition to the simulation, a human machine interface was developed for evaluating the advanced driver assistance system in test runs. The driver assistance system was tested in several situations to show the benefit of the system. It has been tested via multiple test runs. In the following test evaluation the improvement could clearly be shown.:Abkürzungsverzeichnis Symbolverzeichnis 1 Einleitung 1.1 Motivation 1.2 Zielsetzung der Arbeit 1.3 Aufbau der Arbeit 2 Stand der Technik 2.1 System Fahrer-Fahrzeug-Verkehr 2.2 Fahrerassistenzsysteme 2.2.1 Klassifizierung nach Art der Fahrerunterstützung 2.2.2 Klassifizierung nach Fahraufgabenebene 2.2.3 Prädiktive Fahrerassistenzsysteme 2.2.4 Kreuzungsassistenz 2.3 Kooperative Systeme 2.3.1 Forschungsaktivitäten in Europa 2.3.2 Fahrerassistenzsysteme zur Reduktion der Fahrzeugemissionen 2.4 Berechnung des Kraftstoffverbrauches 2.5 Positionsbestimmung im Strassenverkehr 2.5.1 Aufbau eines Satellitennavigationssystems 2.5.2 Ablauf einer Positionsbestimmung 2.5.3 Fehlerquellen und Ursachen bei der Positionsbestimmung 2.5.4 Genauigkeit der Positionsbestimmung 2.5.5 Verarbeitung der Positionsdaten 2.6 Lichtsignalanlagen (LSA) 2.6.1 Definition wichtiger Begriffe 2.6.2 Überblick über Steuerungsverfahren 2.6.3 Umschaltung zwischen Signalprogrammen 2.6.4 Bevorrechtigungsarten für den ÖPNV 3 Analyse des bestehenden Systems 3.1 Fahrprofile zur Annäherung an LSA 3.2 Nutzen des Assistenzsystems 3.3 Ausgangslage des bisherigen Fahrerassistenzsystems 3.3.1 Phasenzyklus 3.3.2 Fahrzeugortung 3.3.3 Kommunikationsdaten des Ampelmoduls 3.3.4 Strategieansatz 3.4 Analyse der Strategieempfehlung 3.5 Optimierungsansätze 4 Erweiterter Systementwurf 4.1 Rahmenbedingungen und Vorgaben 4.2 Entscheidungssystem 4.3 Einfluss von Fahrzeugkolonnen 4.4 Effektive Freigabezeit und Rückstaulänge 4.5 Untersuchung der Geschwindigkeitsregelgrenzen 4.6 ÖPNV - Umgang mit dynamischen Signallaufzeiten 4.7 Ermittlung einer Fahrstrategie 4.8 Zusammenfassung der Optimierung 5 Simulative Untersuchung 5.1 Longitudinalmodell - Intelligent Driver Model – IDM 5.2 Modell zur Schätzung des Kraftstoffverbrauches 5.3 Aufbau des SIMULINK-Modells 5.4 Parametervariation und Ergebnisse 5.4.1 Rahmenbedingungen und Vorgaben 5.4.2 Einfluss der Funkreichweite 5.4.3 Einfluss der Pulklänge 5.5 Zusammenfassung 6 Experimentelle Untersuchung 6.1 Versuchsaufbau 6.2 Mensch Maschine Schnittstelle 6.3 Programmstruktur 6.4 Versuchsdurchführung 6.5 Ergebnis und Zusammenfassung 7 Zusammenfassung und Ausblick A Abbildungsverzeichnis B Tabellenverzeichnis C Literaturverzeichnis D Anhang

Measurements of iron at extreme pressures do not agree on the melting temperature for conditions comparable with those believed to hold at Earth's core. To attempt to determine the stability of relevant lattices, simulations involving a huge amount of particles are needed. In this thesis, a machine learned model is trained to yield results from density functional theory. Different machine learning models are compared. The trained model is then used in molecular dynamics simulations of relevant lattices at a scale too large for density functional theory. / Mätningar av järns smälttemperatur under påfrestningar jämförbara med desom tros gälla i jordens kärna överensstämmer ej. För att försöka bestämma stabiliteten av relevanta gitter krävs simulationer av enorma mängder partiklar. I denna tes tränas en maskininlärd modell att återge resultat från Täthetsfunktionalteori. Olika maskininlärningsmodeller jämförs. Den tränade modellen används sedan i Molekyldynamik-simulationer av relevanta gitter som är förstora för Täthetsfunktionalteori.

Ackumuleringen av plast och mikroplast i miljön är idag en globalt aktuell fråga. Forskning kring mikroplast och dess påverkan på miljö och biota har ökat kraftigt det senaste decenniet. En av de största utsläppskällorna till mikroplast är slitage från vägtrafiken, speciellt från däck, men mikroplast kan även komma från vägmarkeringar. Vägmarkeringar innehåller plastpolymerer (som bindemedel), fyllnadsmedel, pigment och tillsatsämnen (additiv), och ofta ingår även glaspärlor. Vissa ämnen kan ge en negativ påverkan på människa och miljö. I dagsläget saknas det data för att kunna kartlägga i vilken omfattning vägmarkeringsslitage bidrar till spridning av mikroplaster samt för att bedöma om och hur det skulle kunna påverka miljön och vattenlevande organismer. I detta examensarbete har toxicitetstest av lakvatten från vägmarkeringsprodukter utförts med algen Raphidocelis subcapitata för att studera om de är toxiska samt om det finns någon skillnad mellan olika vägmarkeringsprodukter. Partiklar från fyra olika typer av vägmarkeringsprodukter (prefabricerad termoplast, varmapplicerad termoplast, vattenbaserad akrylatfärg och 2-komponentsakrylatfärg) genererades och lakades var för sig med skakning i avjoniserat vatten under 24 timmar. Lakvattnen utan partiklar användes sedan till algtillväxthämningstest. Algerna exponerades under 72 timmar för lakvatten i olika koncentrationer, där den högsta motsvarade 100 g vägmarkeringspartiklar per liter, och algtillväxt mättes. Effektmåtten var maximal tillväxthastighet och lag-fas och dessutom analyserades korrelationen mellan dem som ett mått för anpassningseffektivitet. De fyra lakvattnen påverkade lag-fas och/eller tillväxthastighet i olika omfattning och medförde antingen inhibering eller stimulering av algtillväxten. Lakvattnet från den vattenbaserade akrylatfärgen påvisade störst inhibering av tillväxt och var även det mest toxiska eftersom ingen tillväxtanpassning skedde. För övriga lakvatten påvisades olika grad av anpassningseffektivitet av alger vid exponering. Dock krävs mer ingående statistisk utvärdering för att åtskilja de två lakvatten som hade minst påverkan, dvs. från den prefabricerade och den varmapplicerade termoplasten.  Detta är enbart en första studie. Upprepade tester med fler vägmarkeringsprodukter och fler tester med andra organismer, såsom bakterier, kärlväxter, kräftdjur och fisk, krävs för att bättre kunna utreda om och hur olika vägmarkeringar kan påverka biota. För ytterligare studier skulle det vara intressant att utvärdera vilka ämnen i vägmarkeringar som kan påverka miljön och om dessa skulle kunna ersättas med andra, mindre giftiga ämnen. / The accumulation of plastic and microplastics in the environment is a current global issue. Research on microplastics and its impact on the environment and biota has increased rapidly in the last decade. One of the largest sources of microplastics is wear from road traffic, especially tires, but they can also originate from road markings. Road markings contain plastic polymers (as a binder), fillers, pigments, and additives, and often also glass beads. Some substances may have a negative impact on humans and the environment. At present, there are no data to map the extent to which wear from road markings contributes to the emissions of microplastics, or to assess the effect they might cause on the environment and aquatic organisms. In this thesis, toxicity tests on leachates from road marking products were conducted on the alga Raphidocelis subcapitata to study the effect on the algae and if it differs between the different products.  Particles from four types of road marking products (prefabricated thermoplastic, hot-applied thermoplastic, acrylic water-based paint, and 2-component acrylic paint) were generated and leached separately by shaking in deionized water for 24 hours.  The leachates without particles were used in the standard algal growth inhibition tests. The algae were exposed for 72 hours to the leachates in different concentrations, with the highest corresponding to 100 g road marking particles per liter, and algal growth was monitored. Endpoints used were maximum growth rate and lag phase and, in addition, their correlation was analyzed as an indicator for adaptation capacity. The four leachates affected lag phase and/or growth rate to a varying extent and caused inhibition or stimulation of algae growth. Exposure to leachate from the water-based acrylic paint showed most inhibition of growth and was also the most toxic as no growth adaptation was observed. For the other tests, different rates of adaptation efficiency of the algae growth were found. However, more detailed statistical evaluation is needed to differentiate between the two leachates that had the least effect, i.e. the prefabricated and the hot-applied thermoplastic. This is only a first study. More tests with more road marking products and with other organisms, such as bacteria, vascular plants, crustaceans, and fish, are required to better understand if and how different road markings could affect biota. Additionally, an evaluation of what substances in road marking materials may cause effects and whether these can be replaced by other, less toxic substances, would be of interest.

No description available.

This study presents detailed phonetic and acoustic analyses of the speech characteristics of two new cases of Foreign Accent Syndrome (FAS). Participants include a 48-year-old female who began speaking with an "Eastern European" accent following a traumatic brain injury, and a 45-year-old male who presented with a "British" accent following a subcortical cerebral vascular accident (CVA). Identical samples of the participants' pre- and post-morbid speech were obtained, thus affording a new level of control in the study of Foreign Accent Syndrome. The speech tasks consisted of oral readings of the Grandfather Passage and 18 real words comprised of the stop consonants /p/, /t/, /k/, /b/, /d/, /g/ combined with the peripheral vowels /i/, /a/ and /u/ and ending in a voiceless stop. Computer-based acoustic measures included: 1) voice onset time (VOT), 2) vowel durations, 3) whole word durations, 4) first, second and third formant frequencies, and 5) fundamental frequency. Formant frequencies were measured at three points in the vowel duration: a) 20%, b) 50%, and c) 80% to assess differences in vowel 'onglides' and 'offglides'. The phonetic analysis provided perceptual identification of the major phonetic features associated with the foreign quality of participant's FAS speech, while acoustic measures allowed precise quantification of these features. Results indicated evidence of backing of consonant and vowel productions for both participants. The implications for future research and clinical applications are also considered.

The EU has proposed an ambitious goal to achieve widespread E-mobility in both the electrical and commercial sectors. To accomplish this, a substantial number of DC fast-charging stations must be built. These power converters, installed in the DC fast-charging stations (DCFC), differ from traditional DCDC converters as they exhibit high power density, reaching tens of kilowatts. In contrast to traditional non-isolated power converters, isolated power converters offer ideal galvanic isolation, providing protection to both the local power grid and electric vehicles. Among the DC power converters designed for industrial applications, the LLC resonant converters and DAB converters (Dual Active Bridge) have gained significant popularity. When compared to LLC converters, DAB converters demonstrate a more flexible input and output power range, as well as a higher power density. Considering these advantages, a 10kW bidirectional DAB power converter has been designed for the purpose of fulfilling the requirements of this thesis project. The thesis is organized into four distinct parts. The first part focuses on conducting a comprehensive literature review to explore the challenges prevalent in the current electrical field. Various DC-DC topologies are compared based on different factors, including component analysis, controllability, safety considerations, and cost-effectiveness. By examining these aspects, potential solutions for Electric Vehicles (EVs) are identified. In the second part, a specific DC-DC converter with a power rating of 10kW is chosen, utilizing the DAB (Dual Active Bridge) topology. The selection is based on the analysis conducted in the literature review. The thesis delves into the issues and technical challenges associated with this choice, such as reactive power, peak current, zero-voltage switching (ZVS), and phase shift modulation. These topics are thoroughly explored and discussed within the literature study. The second part of the thesis involves the establishment of a DAB model, incorporating mathematical equations and physical derivations. This modeling and design section discusses the energy conversion process, starting from fundamental physical formulas and extending to the overall system setup. Utilizing the proposed model, a control method called SPS (Single Phase Shift) modulation is implemented in the circuit to achieve closed-loop control. Within this part, the relationship between current, voltage, and output power is derived and utilized for the design of a PI closed controller. To address challenges associated with SPS control, such as reactive power elimination and peak current suppression, an EPS (Enhanced Phase Shift) control scheme is introduced. The EPS control scheme not only fulfills the basic requirement of power transfer but also optimizes the system’s overall efficiency. In the third part of the thesis, a simulation is developed to validate the accuracy of the proposed DAB model and control methods. Simulations are implemented using Simulink, a widely used software for dynamic system modeling and simulation. Various aspects of the system are evaluated through the simulation, including the leakage inductor current, voltage waveforms on both the primary and secondary sides and output power. These parameters are plotted and analyzed to assess the performance of the DAB model and control methods. Additionally, loss and efficiency analyses are conducted using PLECS, a simulation platform that specializes in power electronics systems. By inputting the datasheet information of the switches and transformer, PLECS enables the evaluation of losses and efficiency within the system. This analysis provides valuable insights into the performance and energy efficiency of the proposed DAB-based converter. In the final part of the thesis, conclusions are drawn based on the theoretical findings and simulation results obtained throughout the study. These conclusions reflect the overall outcomes and implications of the research conducted. Furthermore, the future work section outlines the tasks that remain unfinished or areas that can be explored in subsequent studies. This section serves as a guide for future researchers, highlighting potential directions for further investigation and improvement in the field of DAB-based DC-DC converters for E-mobility applications. By presenting the conclusions and future work, the thesis provides a comprehensive summary of the research conducted, its contributions, and potential avenues for future research and development. / EU har föreslagit ett ambitiöst mål för att uppnå utbredd e-mobilitet inom både den elektriska och kommersiella sektorn. För att åstadkomma detta måste ett stort antal DC snabbladdningsstationer byggas. Dessa effektomvandlare, installerade i DC-snabbladdningsstationerna (DCFC), skiljer sig från traditionella DC-DC-omvandlare eftersom de uppvisar hög effekttäthet och når tiotals kilowatt. I motsats till traditionella icke-isolerade kraftomvandlare erbjuder isolerade kraftomvandlare idealisk galvanisk isolering, vilket ger skydd för både det lokala elnätet och elfordon. Bland likströmsomvandlarna som är designade för industriella applikationer har LLC-resonantomvandlarna och DABomvandlarna (Dual Active Bridge) vunnit betydande popularitet. Jämfört med LLC-omvandlare uppvisar DAB-omvandlare ett mer flexibelt in- och uteffektområde, såväl som en högre effekttäthet. Med tanke på dessa fördelar har en 10kW dubbelriktad DAB-effektomvandlare designats för att uppfylla kraven i detta examensarbete. Avhandlingen är organiserad i fyra distinkta delar. Den första delen fokuserar på att genomföra en omfattande litteraturgenomgång för att utforska de utmaningar som råder inom det nuvarande elektriska området. Olika DCDC-topologier jämförs baserat på olika faktorer, inklusive komponentanalys, kontrollerbarhet, säkerhetsöverväganden och kostnadseffektivitet. Genom att undersöka dessa aspekter identifieras potentiella lösningar för elektriska fordon (EV). I den andra delen väljs en specifik DC-DC-omvandlare med en märkeffekt på 10kW, som använder DAB-topologin (Dual Active Bridge). Urvalet baseras på den analys som gjorts i litteraturöversikten. Avhandlingen fördjupar sig i de problem och tekniska utmaningar som är förknippade med detta val, såsom reaktiv effekt, toppström, nollspänningsomkoppling (ZVS) och fasskiftsmodulering. Dessa ämnen utforskas och diskuteras grundligt inom litteraturstudien. Den andra delen av examensarbetet omfattar upprättandet av en DAB-modell, innefattande matematiska ekvationer och fysiska härledningar. Det här avsnittet om modellering och design diskuterar energiomvandlingsprocessen, med start från grundläggande fysiska formler och sträcker sig till den övergripande systemuppställningen. Genom att använda den föreslagna modellen implementeras en styrmetod som kallas SPS-modulering (Single Phase Shift) i kretsen för att uppnå sluten-loop-styrning. Inom denna del härleds förhållandet mellan ström, spänning och uteffekt och används för konstruktionen av en sluten PI-regulator. För att ta itu med utmaningar förknippade med SPS-kontroll, såsom eliminering av reaktiv effekt och undertryckning av toppström, introduceras ett EPS-kontrollschema (Enhanced Phase Shift). EPS-kontrollsystemet uppfyller inte bara det grundläggande kravet på kraftöverföring utan optimerar också systemets totala effektivitet. I den tredje delen av avhandlingen utvecklas en simulering för att validera noggrannheten hos den föreslagna DAB-modellen och styrmetoderna. Simuleringar implementeras med Simulink, en mycket använd programvara för dynamisk systemmodellering och simulering. Olika aspekter av systemet utvärderas genom simuleringen, inklusive läckans induktorström, spänningsvågformer på både primär- och sekundärsidan och uteffekt. Dessa parametrar plottas och analyseras för att bedöma prestandan hos DABmodellen och styrmetoderna. Dessutom genomförs förlust- och effektivitetsanalyser med hjälp av PLECS, en simuleringsplattform som är specialiserad på kraftelektroniksystem. Genom att mata in databladsinformationen för switcharna och transformatorn, möjliggör PLECS utvärdering av förluster och effektivitet i systemet. Denna analys ger värdefulla insikter om prestandan och energieffektiviteten hos den föreslagna DAB-baserade omvandlaren. I den sista delen av uppsatsen dras slutsatser baserat på de teoretiska fynden och simuleringsresultat som erhållits genom studien. Dessa slutsatser speglar de övergripande resultaten och konsekvenserna av den genomförda forskningen. Vidare skisserar det framtida arbetsavsnittet de uppgifter som förblir oavslutade eller områden som kan utforskas i efterföljande studier. Det här avsnittet fungerar som en guide för framtida forskare, och lyfter fram potentiella riktningar för ytterligare undersökningar och förbättringar inom området DAB-baserade DC-DC-omvandlare för e-mobilitetstillämpningar. Genom att presentera slutsatserna och det framtida arbetet ger avhandlingen en omfattande sammanfattning av den forskning som bedrivs, dess bidrag och potentiella vägar för framtida forskning och utveckling.