Bøger udgivet af Cuvillier

This dissertation intends to investigate consumer behaviour with a special emphasis on the influence of sensory food attributes and consumers¿ preferences for these. It highlights the relevance of consumers¿ sensory perception and preferences for the research of food choices and indicates the need for a stronger integration of sensory analysis in food marketing research. This research concern is implemented by using the organic food market as an example that, due to its quality and premium orientation, offers great potentials for differentiation strategies based on taste and other sensory properties. A comprehensive and systematic literature review of international research on organic food consumption behaviour discovers the role that sensory aspects had played until now and reveals the need for more sensory-oriented consumer research. Based on this, in the context of six European organic markets, consumers¿ stated preference and actual sensory preferences are explored, shedding light on the role they play in consumption behaviour. In addition to sensory preferences, the thesis offers insights into a further perceptual construct that appears to be relevant for consumer behaviour, namely the perceived authenticity of traditional food specialties.The concluding section presents the main findings of the six research articles cumulated in the thesis and discusses them with regard to implications for marketing and research. Moreover, it evaluates the limitations of the included studies from which further need for research is derived.

Indium on silicon is a system showing a vast variety of reconstructions depending on preparation and substrate morphology. The (4×1) reconstruction, a self assembled quasi one dimensional chain of indium atoms, can be found among them. It exhibits a reversible phase transition at temperatures of 130 K into a (8 × 2) reconstruction.The nature of the phase transition as well as its driving force have been discussed for more than a decade now. Effects like a Peierls transition, simple lattice distortion and even Jahn-Teller distortions are being considered as the cause of the transition. The question of whether it is of first- or second-order is answered by showing the existence of a robust hysteresis loop of the order parameter, i.e. it is a transition of first-order. The width of the hysteresis of the (4×1)?(8×2) phase-transition is measured by means of high resolution low electron energy diffraction and is determined to be 8.6 K. Furthermore the Si(111)(8×2)-In reconstruction is a system showing a weak correlation between the neighbouring chains which is easily disturbed by adsorbates. The influence of three different adsorbates, namely argon, molecular oxygen and water on the transition characteristics is studied. All of them interact with the surface in a different way. Argon has only a small influence on the transition characteristics and is found to mainly influence the measurement as a diffusive scattering point defect. The expected raise in transition temperature could not be observed. Like argon, the exposure to molecular oxygen seems to reduce the influence of the reconstructions age, i.e. permanent exposure to residual gases, on the transition characteristics. The influence of water adsorption is found to be bigger and contrary to the influence of oxygen and argon. Exposure to small amounts of water heavily disturbs the correlation between rows and growing of (8×2) domains. The reconstruction rapidly ages.Wall et al. excited an extremely undercooled surface state by means of fs-laser excitation as well as to characterize its decay by means of time resolved reflection high electron diffraction. An atomistic model, i.e. a falling row of dominoes, has subsequently been developed. An interesting phenomenon was observed though the rapid ageing of the reconstruction helped explaining it. Necessary expansions of this model are tested by simulating the decay of the high-temperature phase.

Zweiphasenströmungen, insbesondere Wasser/Dampf-Strömungen, sind für die Auslegung und den Betrieb thermohydraulischer Systeme nach wie vor von großem Interesse. Diese Arbeit befasst sich mit der Untersuchung des Druckverlustes und dynamischer Instabilitäten (hier Dichtewellenoszillationen) in Wasser/Dampf-Strömungen mittels zweier unterschiedlicher Ansätze unter praxisnahen Bedingungen. Zum einen wird ein Versuchsstand entwickelt, aufgebaut und in Betrieb genommen, um mit diesem entsprechende Versuche an einem Verdampferrohr durchzuführen. Zum anderen werden dynamische Simulationen mit einem homogenen (¿mixture flow¿) und einem heterogenen (¿two-fluid¿) Strömungsmodell durchgeführt und miteinander und mit den Messdaten verglichen. Die experimentellen und numerischen Ergebnisse lassen sich schließlich in dimensionslosen Stabilitätskarten zusammenfassen, welche die Betriebsgrenzen beschreiben, bei denen Dichtewellenoszillationen in thermohydraulisch ähnlichen Systemen auftreten können.

This book, as a revised edition, is based on its first publication of my Doctor's dissertation at Free University Berlin. Years have passed away since I left the school, but the gratitude still remains till now. My thinks go to my supervisor, Prof. Dr. Gerhard Leitner, who provided me a generous opportunity to do my doctoral study in Berlin and used the facilities of English Department of the Free University, offered me many precious suggestions on how to carry out the study and how to make the dissertation well-organized. I am also indebted to Prof. Dr. Wolfgang Zydatiss, who read through the drafts of this dissertation, gave me valuable guidance, and did most organizing work for me. The topic is on English in China, and my thanks also go to colleagues and friends from China. Thank Dr. Shi Xin for his recommendation on books when I was lost in reading the history of China. Thanks extend to Prof. Mei Renyi and Dr. Lian Jichun, who accepted my interview. Thank Prof. Song Jie, her colleagues and students from Beijing Capital Normal Universtiy, my colleagues and students from Hulunbuir University for their patient cooperation in the response of the questionnaire. Thanks also go to Cuiying, who helped me to solve the problems in my using the software of SPSS.

GaN HEMTs are regarded as one of the most promising RF power transistor technologies thanks to their high-voltage high-speed characteristics. However, they are still known to be prone to trapping effects, which hamper achievable output power and linearity. Hence, accurately and efficiently modeling the trapping effects is crucial in nonlinear large-signal modeling for GaN HEMTs.This work proposes a trap model based on Chalmers model, an industry standard large-signal model. Instead of a complex nonlinear trap description, only four constant parameters of the proposed trap model need to be determined to accurately describe the significant impacts of the trapping effects, e.g., drain-source current slump, typical kink observed in pulsed I/V characteristics, and degradation of the output power. Moreover, the extraction procedure of the trap model parameters is based on pulsed S-parameter measurements, which allow to freeze traps and isolate the trapping effects from self-heating. The model validity is tested through small- and large-signal model verification procedures. Particularly, it is shown that the use of this trap model enables to dramatically improve the large-signal simulation results.

Secondary plant metabolites are part of the plant¿s defense system against biotic and abiotic stresses, such as fungal attack. They are often found in large quantities in the outer layers of plant tissues. These metabolites may serve as natural alternatives to synthetic pesticides and may be recovered from by-products of food processing. The work described in this thesis deals with alkylresorcinols from bran, in particular with a novel process for their fractionation based on deep bed filtration at -80 °C and the determination of their antifungal activity against different Fusarium species. In addition, several phenolic compounds were investigated for their efficiency in a fungicide formulation. Ferulic acid proved to be highly efficient against the phytopathogenic fungus Botrytis cinerea. The fungicide formulation depressed spore germination and mycelial growth, inhibited the growth of fungicide-resistant Botrytis cinerea isolates, and effectively reduced the infection of contaminated table grapes.

It is likely that autonomous vehicles will be the future of mobility. To handle the increase in autonomy, traffic coordination methods will become indispensable. Based on this, an investigation into the performance of Autonomous Vehicle Group Formation (AVGF) based on a decentralized model and a simulative evaluation in urban environments is needed. An Autonomous Vehicle Group (AVG) is a set of vehicles used for transporting people or goods, such as a car, truck, or bus, that are located, gathered, or classed together and are characterized by constant change or progress within the traffic system.The focus is on decentralized autonomous vehicle grouping, which allows the flexibility of single vehicles to be retained while also enabling the use of group coordination to achieve higher throughput in urban networks, as already witnessed in highway vehicular platoons. A known and practiced concept for urban traffic control at traffic signals is to bundle vehicles passively according to green signal phases; the novelty being active coordination of the vehicles in decentralized groups of interests. Likewise, AVGs make coordinated decisions with and without communication depending on the similarities of their vehicle properties and destinations. AVGs coordinate the motion of traffic, making strategic (i.e., group destination) and tactical (i.e., speed and gaps) group decisions in a street network.

The main target of this thesis is to gain a deeper understanding of the reduction chemistry of group 16 elements (sulfur, selenium and tellurium) and their derivatives by using divalent lanthanide reagents as reduction agents. Different from cyclopentadienyl counterparts reported by Evans, the employed formidinate lanthanides in this work are supported by a sterically more demanding ligand and the reactivity of these complexes has been discussed by Junk and Deacon and proved by previous work of Roesky et al. The initial target of this project is the reduction of elemental chalcogens by [(DippForm)2Ln(THF)2]. Nano-sized selenium and tellurium were prepared considering the poor solubility of them. As part of the major focus, it is also interesting to study the reduction of diphenyldichalcogenides Ph2E2 (E = S, Se, Te) and perfluorinated diphenyldiselenides (4-RC6H4Se)2 (R = F, OMe) in order to determine whether this reaction can be used for the synthesis of a broad class of such compounds. Moreover, based on the previous study on lanthanides, it is also of interest to extend such reduction chemistry to transition metal complexes. However, as a minor target of this project and also a very initial study, such extension limits only to [(DippNafnaf)Fe(C7H8)] (DippNafnaf = CH[CHN]2). Due to the high reactivity of FeI complex and interesting application potentials of ¿-diketiminato ligand supported iron chalcogenides, the reaction between [(DippNafnaf)Fe(toluene)] and elemental chalcogens has the potential to give some interesting results and thus was studied.

In this thesis a parallel simulation platform, namely TOUGH2MP-FLAC3Dplus, was further developed by linking the multiphase multicomponent flow code TOUGH2MP and the further developed geomechanical code FLAC3Dplus for large-scale simulation of the coupled THM/C processes related to geo-energy production. A series of mathematical/physical models were developed and implemented in this platform, including (1) an improved equation of state for CO2-CH4-H2O-NaCl system which considers the effect of salt on phase partition and fluid properties in gas reservoirs; (2) a modified coupling approach for the simulation of hydraulic fracturing in tight geo-reservoirs, which considers the multiphase multicomponent leakoff effects; (3) a thermo-hydro-mechanical model based on a crack tensor for naturally fractured rock masses and faults. All these verified models have been applied in three different case studies, including CO2 enhanced gas recovery (EGR) in the Altmark natural gas field; (2) Hydraulic fracturing in three different types of geo-reservoirs (tight gas, oil and geothermal reservoir); (3) Geothermal energy utilization induced seismicity in Unterhaching. The developed models and the numerical platform can be used to predict the coupled THM/C behavior of rock formations, to optimize the CO2-EGR and hydraulic fracturing in tight geo-reservoirs, as well as reduce the geo-risks related to geo-energy production.

Childhood seems to represent an important timeline of vulnerability. Previous research indicates that first symptoms of many adult psychopathologies such as depression, anxiety, antisocial personality disorders, etc. can already be observed in early childhood. Therefore, it is crucial to understand the dynamics that lead to maladaptive development, known to pose various challenges on individuals, families, and society. Biological embedding is seen as one underlying mechanism. In this process, early childhood adversities are assumed to result in enduring changes in systems responsible for the physiological stability of an organism, which then may have detrimental consequences for the physical and mental health.The aim of the present thesis was to provide a different perspective on adaptive child development, and how it is influenced by various risk and protective factors. Moreover, it aims to contribute to a better understanding of underlying biological mechanisms, investigating the associations between stress-related biological parameters and risk and protective factors in early childhood.

Depression is the most predominant of all childbearing mental illnesses and a leading cause of disability in women in reproductive age (O¿Hara & Swain, 1996; Nobel, 2005). Previous research has shown that high levels of depression or anxiety in women during pregnancy double their children¿s risk for attention deficit hyperactivity disorder (ADHD), conduct disorders, difficult temperament and behavioural problems later on (O'Connor, Heron, Golding, Beveridge & Glover, 2002). Prenatal depression and anxiety contribute an estimated 10-15% of the variance in these outcomes (Talge, Neal & Glover, 2007).

This publication examines Europe¿s strong dependency on importing essential minerals and metals for their industries and if a strategic European Union Sovereign Wealth Fund (EUSWF) is a possible solution for investing directly in producing countries in order to maximize the security of supply. This would be advanced measures for the ¿Raw Materials Initiative¿ (RMI) which has been launched by the European Commission in 2008 to react to the future development of minerals and metals which faced a scarcity based on natural limitation and increasing prices. Both are driven by a global shift from western economies to eastern economies based on booming economies and their high demand to satisfy the growth. The publication states that countries with a state capitalism have direct access to these relevant minerals and metals neither through their state-owned enterprises in their own economies nor through strategic foreign direct investments (FDI) in these elements by Sovereign Wealth Funds (SWFs) or state-owned enterprises, too. The results of the survey show that these economies are going to have or already have an advantage attributable to this behaviour and that the European Union (EU) missed this opportunity decades ago. Moreover does this way of political behaviour not coincide with the idea of a capitalist economic system, which is based on a free and fair trade. Finally, the EU seems to cooperate in this issue less than they should or might be able to. Indications were found related to the Europe 2020 strategy that the EU could overcome this weakness.

Open innovation as a multilateral form of cooperation has become a growing trend across industries, as companies are increasingly searching for new innovation opportunities in their external environment. The aim of this thesis was to analyze whether companies that emphasize open innovation can positively influence their innovation performance and which open innovation activities contribute the most. The study distinguished between the core processes of open innovation. R&D cooperation with different stakeholders was analyzed by regarding the outside-in process, and additional commercialization channels for internal knowledge were analyzed by examining the inside-out process. The study included firms¿ internal perspective, which encompasses internal teamwork and the corporate innovation culture. Web 2.0 and social networking technologies were also considered, as their use has steadily increased in recent years.

This dissertation investigates the interaction between control and motivation in employment relationships. In a simple experimental setting, the agent chooses among effort levels after the principal determined the agent¿s choice set. Effort bears costs for the agent and benefits for the principal. The extent to which the principal restricts the agent¿s choice set corresponds to the level of control. Whether control is beneficial to the principal depends on the relative size of the disciplining and the crowding-out effects which are likely to vary with individual, situational and cultural conditions.The first study (Chapter 2) reports on a robustness check of the surprising findings by Falk and Kosfeld (2006) who show that hidden costs outweigh the benefits of control in anonymous principal-agent relationships. Our results largely confirm the existence of hidden costs of control, but they are usually not substantial enough to outweigh the benefits. Preliminary findings on the relationship between demographics and control aversion do not allow clear conclusions.The second study (Chapter 3) provides an experimental test of Frey¿s (1993) argument that control aversion increases with the closeness of the principal-agent relationship. This study also addresses methodological issues. We compare a laboratory and an internet implementation of a repeated principal-agent game where the principal can impose control at two different levels. Control aversion is stronger in the laboratory than on the internet, which confirms Frey¿s argument.The third study (Chapter 4) investigates whether the nature of politico-economic systems influences control preferences. In a large-scale internet study, we test the hypothesis that less individuals acquired control-averse preferences under the coercive regime of East Germany than under the liberal regime of West Germany. Indeed, control aversion is largely stronger among West Germans than among East Germans, and the differences are more pronounced for elder than for younger generations.

Consumers in Germany show an increasing interest in agricultural products that are associated with their region of origin. Therefore, on the side of producers, the increase in agricultural products registered as Geographical Indication (GI) products indicates a growing interest in this field. Considering the demand for GI products and an increasing number of agricultural products proposed as GI products, characterizing the geographical origin of the products is required to provide supplementary information to both the consumer and the producer, as well as protect them from fraud and the exploitation of the trust consumers have in their quality.Potatoes, one of the GI commodities in Germany, are cultivated mostly in the northern, western and southern parts of the country. These three main potato-producing regions are characterized by different altitudes and are located in relatively different latitudinal coordinates. This leads to different environmental conditions, such as temperature and precipitation rates. These environmental conditions may influence the chemical composition and quality parameters of the potato tubers. Therefore, their geographical origin may be a relevant quality parameter. ACD, one of the important quality parameters, is influenced by the chemical composition of a tuber, of which organic acids and minerals are the most relevant to its determination.Based on the background above, this study aims to characterize the geographical origin of potato tubers in Germany, particularly those from the northern, western and southern regions of the country; to evaluate the ACD of table potatoes cultivated in the three considered regions and to evaluate the contribution of selected tuber constituents to ACD.The characterization of the geographical origin of the potato tubers was conducted with two discriminate parameters: stable isotope ratios and mineral compositions. Several cultivars were collected in 2010 and 2011 from the northern, western and southern regions. Their isotopic ratios and mineral compositions were analyzed.

¿The wish of all human beings is to live as long as possible and to remain healthy and active, also in their old age.¿This presentation will focus on the educational campaign to enlighten Nigerians on the specific problems besetting their health, the problems of aging, longevity, and reasons for premature death, healthy living and the role of nutrition in regard to our health, in particular, preventive strategies and measures. These form the basis of ANTI-AGING MEDICINE, the magical, medical buzz-word of the 21st. Century. Because of the importance that is attached to the health of the people, I feel indebted and motivated to contribute, in this way, by starting this educational enlightenment campaign to create awareness and to sensitize our people to factors that pose problems for their health and which, in the long run, will also determine how sick or healthy they will be later in life. Without good information on health problems and the causes of the simplest sicknesses, many of our people, due to ignorance, may not be in a position to react early enough, to take preventive measures or even to see the medical doctor before it is too late.

Currently, software-intensive safety-critical systems assume mostly static software configurations. This is in contrast to other, non-critical software intensive systems such as smart phones or gaming consoles, where software updates are common practice. One of the factors prohibiting flexibility in critical systems are existing certification processes. The effort necessary to re-certify the product after an update in many cases prohibits wide-spread in-field deployment of software, where it is not absolutely necessary (e.g. to fix bugs).This thesis presents an approach allowing flexibility in safety-critical systems. It presents a generic architecture template for a runtime environment, which loosely couples a potentially complex admission control scheme with a lean execution environment for operation. The admission control scheme as well as the configuration of the execution environment are based on contracts between the runtime environment and applications running on the system. In cases where the admission control scheme is sufficiently powerful to replace manual verification, such an approach could enable flexibility also in critical systems.The main contribution of this thesis concerns one modeling scheme that could back such an admission control scheme. This thesis focuses on system timing as one aspect of safety-critical systems. Here, an existing formal analysis method (Compositional Performance Analysis) is transformed into a distributed algorithm, which could back an admission control scheme in the proposed architecture. In order to prove the transformation tractable, a novel formalization of the existing modeling and analysis scheme is presented, which enables reasoning about quality and existence of solutions as well as applicable algorithms.

Outdoor group housing is increasingly recognized as an appropriate housing system for horses. However, ambient temperatures in Central Europe can range from -25°C in winter to +35°C in summer, thus exposing animals to extreme environmental conditions. Simultaneously, food quantity and quality may vary substantially with seasons. Whether domesticated horses can adapt to these harsh conditions, like their wild ancestor the Przewalski horse, has been in debate, because domestication represents a manipulation of the natural selection process. Little information is available on the behaviour of domestic horses under such conditions. Therefore, this dissertation analysed physiological and behavioural adaptation strategies of a robust domesticated horse breed, the Shetland pony, under semi-extensive housing conditions. The main focus was on changes in metabolic rate, water metabolism, locomotor activity, lying time and several blood parameters over the course of a year.Die Gruppenhaltung von Pferden unter Außenklimabedingungen wird zunehmend als tiergerechte Haltungsform angesehen. Allerdings sind die Pferde dabei starken klimatischen Schwankungen ausgesetzt, da die Umgebungstemperaturen in Zentraleuropa von -25°C im Winter bis +35 °C im Sommer reichen können. Gleichzeitig kann die Futterqualität und -quantität erheblich innerhalb des Jahres schwanken. Da die Domestikation eine Manipulation der natürlichen Selektion darstellt, ist es fraglich, ob sich domestizierte Pferde, wie ihre wilden Verwandten, die Przewalski Pferde, an solch raue Umweltbedingungen anpassen können. Bisher gibt es wenige Informationen über das Verhalten domestizierter Pferde unter solchen Haltungsbedingungen. Ziel dieser Dissertation war folglich die Analyse von Verhaltensänderungen und physiologischer Adaptationen einer domestizierten, robusten Pferderasse, dem Shetland Pony, unter semi-extensiven Haltungsbedingungen. Das Hauptaugenmerk liegt dabei auf Änderungen der Stoffwechselaktivität, des Wasserumsatzes, der Bewegungsaktivität und der Liegedauer sowie unterschiedlicher Blutparameter im Jahresverlauf.

Polyamides, due to their extreme durability and strength, are important industrial polymers used e.g. in the automotive industry or in high-value consumer products. Their production from petrochemically derived monomers suffers from the shortage of fossil fuels, rising oil prices, escalating CO2 production as well as low eco-efficiency. Most valuable alternatives are biotechnological processes from renewable resources for the production. Thereby, 1,5 diaminopentane is a promising monomer building block for completely bio-based polyamides like PA 5.4 or PA 5.10. In a first proof of concept, the product spectrum of Corynebacterium glutamicum was broadened towards the novel non-natural product diaminopentane by heterologous expression of an Escherichia coli lysine decarboxylase. An important criterion for the successful implementation of such bio-processes is their economic competitiveness with conventional techniques, demanding for efficient microbial production strains. In this work, synthetic metabolic engineering was applied to create an industrial C. glutamicum diaminopentane-producing strain with excellent production properties in a well-defined genomic context. Computational genome-scale modeling was used to investigate the metabolic properties of the bacterium in silico and to predict concepts for global strain design. By introduction of the identified beneficial genetic targets, the metabolism of the C. glutamicum wild type was systematically modified following the key-characteristics required for optimal production: (i) enhancement of the biosynthetic capacity of diaminopentane from its building blocks, (ii) improved supply of the carbon building blocks, (iii) reduced withdrawal of carbon for competing reactions, (iv) engineering of cellular transport, and (v) improved co-factor supply. For strain characterization, state-of-the-art omics technologies were applied. Thereby, metabolomics led to the discovery and subsequent identification of the so far unknown by-product N-acetyl-diaminopentane, transcriptomics enabled the identification of novel targets for enhancing the production properties, and fluxomics was applied to gain a detailed insight into the physiology of the constructed mutants. The final engineered C. glutamicum strain, carrying a set of 16 stable genomic modifications, achieved a remarkable diaminopentane yield of 41 % in shake flasks on glucose minimal medium. The production performance of the rational designed strain was also investigated under industrial conditions in a fed-batch fermentation on glucose based complex medium. In this process, the hyper-producer exhibited a final diaminopentane¿2 HCl titer of 150 g L 1 after 50 h, a constant diaminopentane yield of 50 %, and a maximum productivity of 3.8 g L h-1 in the feed-phase, a benchmark in the bio-based production of novel polymers. Concluding, this work marks a milestone towards biotechnological processes for the production of building blocks for bio-based and high-value added polyamides, one of the most important industrial polymers used worldwide.

The rush of marketing expenditures in the Internet has made effectiveness andefficiency increasingly relevant. In particular, online firms offering free contentneed to provide powerful marketing tools to advertisers to support their ownbusiness models. Behavioral targeting enables websites to selectively displayadvertisements to consumers according to their surfing profiles, makingadvertisements more relevant, and thereby increasing advertising revenues fromwebsites. Consequently, it is often seen as a savior by online firms struggling tofinance their free content. However, targeting can raise privacy concerns, leadingto negative consumer reactions. Furthermore, there is increasing regulatorypressure for websites to inform surfers about targeting practices and provide themwith opt-in or opt-out functions. Proactively addressing those challenges tosustain revenues from targeted advertising is highly important¿in particular foradvertising-supported websites¿and requires systematic research. Such research,though, has to account for the fact that the profiling of consumers to increaseadvertising revenues raises ethical questions, especially because targeting oftenoccurs without consumers¿ knowledge.This doctoral dissertation studies consumer privacy concerns with regard to onlinetargeting practices. Specifically, it investigates how privacy concerns affectconsumers¿ perceptions of targeted advertisements. Furthermore, building onsocial exchange theory, fairness norms, and previous research on consumerprivacy concerns in related areas, such as direct mail and e-commerce, I developtangible, managerial operational mechanisms to increase consumers¿ acceptanceof targeting and improve consumers¿ perceptions of targeted advertisements. Inorder to ensure that these mechanisms are in line with principles of businessethics, I derive normative requirements for these mechanisms from integrativesocial contracts theory.

The Mobile VISMA is a power electronics device for V2G applications which behaves like an electromechanical synchronous machine and offers the same beneficial properties to the power network, increasing inertia in the system, stabilizing the grid voltage, and providing a short-circuit current in case of grid faults. The VISMA performs a real-time simulation of a synchronous machine and calculates the phase currents that an electromagnetic synchronous machine would produce under the same local grid conditions. These currents are fed into the grid using a current-controlled inverter.In this dissertation the requirements for a machine model suitable for the VISMA are set, and a mathematical model suitable for use in the VISMA algorithm is found and implemented. A new hardware architecture for the Mobile VISMA based on microcontroller and FPGA technologies is presented. The new architecture allows the reduction of the size and cost of the VISMA, making it suitable for installation in electric vehicles. A simulation model of the inverter hardware and hysteresis current controller is created and validated by experiment. The verified hardware model is then used to design a new type of PWM-based current controller. The performance of the hysteresis- and PWM-based current controllers is evaluated and compared. Finally, the behavior of the VISMA during power network faults is examined, and it is shown that the VISMA, inverter hardware, and current controllers are capable of fault ride-through and can support the power network during faults.

Durch die fortschreitende Etablierung der wertorientierten Unternehmensführung werden Kundenbeziehungen zunehmend in Abhängigkeit von ihrem wirtschaftlichen Erfolgsbeitrag betrachtet. Zur Bewertung von langfristig vorteilhaften Kundenbeziehungen, effizienten Res-sourcenallokationen und Identifikation von wertsteigernden Kundenbeziehungsmaßnahmen gewinnt der Kundenwert daher als Performancekennzahl an Bedeutung. Neben der Heraus-forderung, ein einheitliches Kundenwertverständnis zwischen den Disziplinen Marketing und Controlling zu entwickeln, sehen sich Unternehmen mit der Notwendigkeit einer Integration von Kundendynamiken in die Kundenbewertung konfrontiert. Denn durch steigende Informa-tionsverfügbarkeit und Angebotsflexibilität zeigt sich ein zunehmend dynamisches Kunden-verhalten, wodurch Investitionen in unrentable Kundenbeziehungen schnell erhebliche finan-zielle Einbußen nach sich ziehen können.Das vorliegende Buch beschäftigt sich mit der Bewertung von dynamischen Kundenbezie-hungen an der Schnittstelle zwischen Marketing und Controlling. Im Rahmen von fünf unab-hängigen Kapiteln wird einerseits untersucht, welche Effekte der Kundenwert auf die Unter-nehmensperformance hat und durch welche Faktoren dieser determiniert wird. Andererseits wird auf Basis von innovativen Methoden ein dynamisches Kundenbewertungsmodell entwi-ckelt und in den übergeordneten Performance Management Prozess eingeordnet. Der erfolg-reiche Einsatz des analytischen Bewertungsmodells zur Steuerung von Kundensegmenten wird bei Unternehmen mit unterschiedlichen Vertragsbeziehungen empirisch validiert.

Gallium nitride (GaN)-based High Electron Mobility Transistors (HEMTs) for high voltage, high power switching and regulating for space applications are studied in this work. Efficient power switching is associated with operation in high OFF-state blocking voltage while keeping the ON-state resistance, the dynamic dispersion and leakage currents as low as possible. The potential of such devices to operate at high voltages is limited by a chain of factors such as subthreshold leakages and the device geometry. Blocking voltage enhancement is a complicated problem that requires parallel methods for solution; epitaxial layers design, device structural and geometry design, and suitable semiconductor manufacturing technique.In this work physical-based device simulation as an engineering tool was developed. An overview on GaN-based HEMTs physical based device simulation using Silvaco-¿ATLAS¿ is given. The simulation is utilized to analyze, give insight to the modes of operation of the device and for design and evaluation of innovative concepts. Physical-based models that describe the properties of the semiconductor material are introduced. A detailed description of the specific AlGaN/GaN HEMT structure definition and geometries are given along with the complex fine meshing requirements. Nitride-semiconductor specific material properties and their physical models are reviewed focusing on the energetic band structure, epitaxial strain tensor calculation in wurtzite materials and build-in polarization models. Special attention for thermal conductivity, carriers¿ mobility and Schottky-gate-reverse-bias-tunneling is paid. Empirical parameters matching and adjustment of models parameters to match the experimental device measured results are discussed.

Solid dispersions are a promising approach for controlled release drug delivery systems as both the bioavailability enhancement of poorly water-soluble drugs as well as the sustained release of water-soluble drugs are possible to optimize their in vivo performance.Different methods for the manufacture of solid dispersion systems have been introduced in literature. In the present work, two methods are compared: hot-melt extrusion and ultrasound-assisted compaction technique. Various carrier systems and drugs with different physicochemical properties are applied to investigate the feasibility of the technologies for pharmaceutical formulation. The formulations are compared to the corresponding untreated physical blends of the components regarding their solid state structure and dissolution behavior to assess the effect of the manufacturing technique.

Die Einführung von aktiven Sicherheitssystemen, basierend auf Fahrzeug-zu-Fahrzeug Kommunikation, hat ein großes Potential, die immer noch hohe Zahl von Verletzten und tödlich Verunglückten deutlich zu reduzieren. Dabei werden die Fahrzeuge befähigt, regelmäßig und zusätzlich ereignisbasiert ihren Status anderen umliegenden Fahrzeugen mitzuteilen. In diesem Sinne wird die aktive Sicherheit für Fahrer und Insassen erhöht, weil jederzeit zuverlässige, hochaktuelle und sehr genaue Informationen zur Verfügung stehen.Derzeit werden die Protokolle und Mechanismen für die Fahrzeug-zu-Fahrzeug Kommunikation in verschiedenen Gremien standardisiert. In Europa ist hierfür das European Telecommunications Standards Institute (ETSI) zuständig. Für die Applikationsschicht sieht ETSI vor, dass drei verschiedene Nachrichtentypen für den Broadcast zur Verfügung stehen: die periodischen Cooperative Awareness Messages (CAMs), ereignisbasierte Decentralized Environmental Notification Messages (DENMs) und dienstorientierte Service Announcement Messages (SAMs). Insbesondere die Kommunikationslast, die durch die periodischen CAMs entsteht, kann leicht dazu führen, dass der Kommunikationskanal in Überlast gerät. Dabei handelt es sich um das grundsätzlich bekannte Problem der Skalierbarkeit des Medienzugriffs in drahtlosen Netzen, die deutlich mehr als 100 Knoten beinhalten (siehe z.B. 21).