Bøger udgivet af Cuvillier

Die Dissertation zeigt die Potentiale von Informationssystemen zur Förderung ökologischnachhaltigen Verhaltens auf. Zunächst werden bestehende Lösungsansätze aus der Wissenschaft undPraxis vorgestellt, um so den Status Quo nutzerorientierter nachhaltiger Informationssysteme (GreenIS) darzustellen. Weiterhin werden angewendete psychologische Theorien und technischeGestaltungsprinzipien (Design-Prinzipien) zur Förderung von Verhaltungsveränderung aufgedecktund dessen Passung sowie Wirkung analysiert. Basierend auf den gewonnenen Erkenntnissenwerden Empfehlungen zur Gestaltung nutzerorientierter Green IS abgeleitet mit dem Ziel langfristigeVerhaltensveränderung zu erreichen. Darüber hinaus wird die Akzeptanz solcher Systeme ermittelt,und analysiert wie eine Steigerung der Akzeptanz initiiert werden kann. Neben der Präsentation dergewonnen wissenschaftlichen und praxisbezogenen Erkenntnisse im Kontext nutzerorientierternachhaltiger Green IS, leistet diese Arbeit einen Beitrag zur Wahrnehmungssteigerung solcherSysteme. Zudem werden Grundlagen für weitere Forschung innerhalb des noch jungenForschungsgebiets unter Berücksichtigung persuasiver Design-Prinzipien geschaffen.This dissertation shows the potential of information systems to promote and invoke environmentalsustainable behavior. At first, an overview of existing approaches in research and practice is providedin order to illustrate the status quo of user-centric environmental sustainable information systems(Green IS). Furthermore, various applied theories from psychology as well as technological designprinciplesare revealed and analyzed regarding their suitability and effect in context of behavioralchange. Based on these findings recommendations for the design of user-centric Green IS arededuced in order to achieve long-term behavior change. Moreover, an analysis of the acceptance ofsuch systems is performed. Alongside the presentation of the central findings for theory and practicethis thesis also contributes to an increase of people¿s awareness of these systems regarding theirexistence and potential. Also, this dissertation builds the foundation for future research in this youngresearch field of persuasive user-centric Green IS.

The Anacardiaceae (¿cashew family¿) include a number of well-known edible species such as mango, pistachio, cashew, marula, sumach, and peppertree. This family is characterized by the presence of a broad profile of polyphenols, which are secondary metabolites that protect plants from biotic and abiotic stress. This thesis addresses the phenolic composition of fruits of the Brazilian peppertree (Schinus terebinthifolius Raddi), which are used as a spice. Using LC-MS and 2D NMR spectroscopy, 30 phenolic compounds were described for S. terebinthifolius, many of them for the first time. The fruits of the closely related Peruvian peppertree (Schinus molle L.) were also characterized and a method for the phytochemical differentiation of the two spices was proposed. Based on these studies, chemotaxonomic traits within the Anacardiaceae could be established. Furthermore, the pressurized liquid extraction of polyphenols was optimized and a multi-step process was presented, which allows the purification and isolation of bioactive compounds from Schinus species for future use in bioassays. In conclusion, this work provides novel insights into the phenolic profile of these fruits and paves the way for further investigations into their bio-functional and techno-functional properties.

The publication is indicating that there is a fundamental coincidence existing between the dynamics being inherent to acoustic and electromagnetic fields. This entails that the wave propagation speed in both media is related to an identical physical background. The particles in the electromagnetic field are vibrating at a celerity being lower than the light propagation speed c.Energy conservation considerations indicate that both the acoustic and electromagnetic fields need to be extended by a rotational field. The energy inherent to this rotational field is related to the thermodynamic ¿inner energy¿ of the medium.The validation of the developed theoretical fundamentals is based on the so-called ¿black body radiation specträ. Thereby also an explanation as to the non-existence of the ¿ultraviolet catastrophe¿ will be given. The mass of the electromagnetic particle, being at 2,04¿10-40 kg, will be derived from a thermodynamic approach.

The aim of this work is to advance the knowledge on the behavior of fluids in porous materials. Wicking, or imbibition, is a spontaneous penetration of liquid into porous media due to capillary forces. Due to the challenges of the capillary transport of cryogenic liquids, the wicking of liquid nitrogen subjected to evaporation was of a special interest for this research. For that, a novel test facility was built to perform experiments in a one-species system under pre-defined non-isothermal conditions. Two one-dimensional macroscopic wicking models were proposed to evaluate the impact of the porous sample superheat, geometrical and structural characteristics as well as the impact of the vapor flow created due to evaporation. In the second part of this work, the capillary transport abilities of porous ceramic monoliths of anisotropic structure were studied. The polymer-derived ceramic samples fabricated with the freeze-casting method were characterized via vertical wicking tests. In the third part, the capillary transport properties of porous media and the wicking process were examined using the computational fluid dynamics software. The results of benchmark microscopic and macroscopic simulations may serve as a basis for further numerical investigations of fluid flow problems in porous media.

The work analyses structural, institutional and political determinants of Ukrainian agricultural policy at the end of the 21st century¿s first decade. Besides identifying the relevant actors in the policy domain and their interrelations, the study aims to shed light on preferences and general orientation about topical agricultural issues. The results differentiate between four ideological clusters preferring similar positions. Further objectives refer to the influence of institutional and structural factors on the determination of policy outcomes under different scenarios. To this end, the study not only deals with the constitutional order of the political system, in which decisions are formally adopted and implemented, but also with role and access structures of agricultural interest groups. The measured overall political control outflow from politicians to the interest groups amounts to 16.5%. Furthermore, the work econometrically examines the influence of special interests on agricultural trade policy formation and finds evidence that lower import-to-output ratios lead to higher protection levels in sectors dominated by commercial agriculture.

Die Dissertation ¿Credit Risk Parameter Modelling in Financial Institutions¿ beschäftigt sich mit dem Modellieren von Kreditrisikoparametern in Finanzinstituten. Einerseits kann für die Schätzung von Kreditrisikoparametern eine Verbesserung der verwendeten Information erzielt werden, und andererseits kann das Modell oder die Technik zur Schätzung der Parameter selbst verbessert werden. Vor diesem Hintergrund werden in dieser Arbeit drei relevante Forschungsfragen bearbeitet:- Wie können Finanzintermediäre Informationssynergien (engl. economies of scope) zwischen verschiedenen privaten Informationsquellen nutzen, um Kreditrisiko und Kundenbeziehungen zielgerichtet zu steuern?- Wie kann die Wahl eines Kunden für eine bestimmte Ausgestaltung eines Finanzproduktes erklärt werden? Was kann man über den Kunden durch seine Auswahl lernen? Existiert ein Zusammenhang zwischen dem Ausfallrisiko des Kunden und seiner Auswahl?- Wie können Finanzintermediäre eine unverzerrte erwartete Forderungshöhe bei Ausfall modellieren? Welches ist die geeignete Methode um eine solche erwartete Forderungshöhe bei Ausfall zu schätzen?

This dissertation explores different implementation strategies for the fragment-forwarding aspect of the 6LoWPAN protocol for ¿low power and lossy networks¿ (LLNs). The performance in terms of latency and reliability for the LLN-typical collection traffic pattern is analyzed for several ¿direct¿ and ¿reassembling¿ strategies. A novel approach based on snooping and suspending transmissions is developed and it is shown that this approach improves the end-to-reliability significantly in most of the evaluated simulation and testbed scenarios.

Tropentag is an annual international conference on food security, natural resource management and rural development. Tropentag 2017 is organised by the University of Bonn, Germany, jointly with the Council for Tropical and Subtropical Research (ATSAF e.V) in cooperation with the GIZ Advisory Service on Agricultural Research for Development (BEAF). This year¿s Conference theme is ¿Future Agriculture: social-ecological transitions and bio-cultural shifts¿.Future agriculture is by definition an emerging phenomenon. It is continuously in the making, while present visions of the future turn into history. Vast stretches of land in developing countries are being put to new uses, with new forms of governance, new ownership patterns and new forms of production. Particularly agricultural systems are undergoing drastic changes, unfolding an enormous transformative power and affecting millions of people.System-immanent attributes such as visions, aspirations, cultural specifics and production factor availability shape the response of land users to growing external pressures such as climate change, market demands, land degradation, emerging diseases and policies. In addition to such social-ecological transitions, substantial bio-cultural shifts occur and are imposed by centrally-planned establishments of large-scale intensification (or conservation) corridors and protection zones, or are associated with infrastructure development and urbanisation processes. A wide array of resulting response pathways and land use or production strategies emerge that may be beneficial for rural and urban populations, but can also lead to abandonment of land, migration and conflicts.

Actuaries working in claims reserving are often faced, among others, with the following two tasks: the prediction of future outstanding loss liabilities, as well as the quantification of their risk. Within claims reserving there exist various methods in which vagueness and subjective judgement is often not considered. A formal approach is given e.g. by fuzzy set theory.Besides an overview of applications of fuzzy set theory in claims reserving the author presents three ways of how subjective assessment can be implemented in the chain-ladder as well as the Bornhuetter Ferguson method.

Cereal grains, such as rye and triticale are a major source of energy in pig nutrition. The crude protein (CP) content in cereal grains is rather low compared to protein ingredients such as soybean meal. However, costs and availability of soybean meal are strongly correlated with the price development of agricultural commodities on the world market. Therefore, swine producers will make increasing efforts to use protein from locally produced cereal grains more efficiently to reduce feed costs. Measurements of apparent (AID) and standardized ileal digestibility (SID) of CP and AA are frequently used to estimate the amounts of absorbable AA from the diet which are used for pigs¿ metabolic processes. However, until now there is limited data on SID of CP and AA in rye and triticale, particularly in new genotypes. Therefore, one objective of the present work was to determine the variation in nutritional composition and SID of CP and AA of 8 currently available rye and 8 triticale genotypes. Standardized ileal digestibility of CP and most AA between the 8 assayed genotypes of both rye and triticale did not differ. Furthermore, average SID values of CP and AA of both rye and triticale in the present experiment were lower when compared to values of rye and triticale published in current feed tables. Thus, future research should clarify, whether these differences in comparison to feed tables are caused by experimental conditions or reflect a consistent decrease that need to be accounted for in feed tables.

Die vorliegende Arbeit entwickelt einen neuen methodologischen Ansatz zur ökologisch-ökonomischen Bewertung landwirtschaftlicher Grünlandsysteme in den ukrainischen Karpaten. Dieser basiert auf Methoden der und wird auf eine Region angewendet, die durch eine traditionelle Semi-Subsistenzlandwirtschaft gekennzeichnet ist.Verschiedene Einflussgrößen machen diese Art von Landwirtschaft zu einem relativ stabilen System, das sich vor allem durch ein Gleichgewicht von landwirtschaftlicher Produktion und der Bereitstellung von Umweltleistungen, hierbei vor allem durch eine hohe Artenvielfalt auszeichnet. Dennoch ist eine Erosion der Konnektivität zwischen Landwirt und Natur festzustellen, denn die jungen Landwirte sind nicht mehr daran interessiert, traditionelle Bewirtschaftungsmethoden anzuwenden, weil diese sehr arbeitsintensiv sind und keine hohen Gewinne erwarten lassen. Folglich ist ein Bevölkerungsschwund durch Abwanderung festzustellen. Nur Landwirtschaft mit geringer Intensität kann jedoch hohe Niveaus von Biodiversität bereitstellen, während eine Intensivierung zwangsläufig zu Biodiversitätsverlusten führen wird.

In dieser interdisziplinären Arbeit werden die dielektrischen Eigenschaften von kontinuierlich steuerbaren ferroelektrischen Materialien hinsichtlich ihrer Eigenschaften im Hochleistungsbetrieb untersucht. Die dabei durchgeführten Untersuchungen reichen von der Materialebene, über die Modellierung der Komponenten bis hin zur Synthese von steuerbaren Hochfrequenzschaltungen.Ein CAD-Ansatz zur Modellierung steuerbarer Kompositkeramiken wird vorgestellt. In dem vorgeschlagenen Modell werden zusätzliche Freiheitsgrade eingeführt, wodurch eine, im Vergleich zu bereits etablierten Methoden, akkuratere Beschreibung von zweiphasigen Kompositmaterialien gezeigt wird.Erste systematische Untersuchungen von steuerbaren, auf Ferroelektrika basierten, Parallelplatenkondensatoren und uniplanaren Interdigitalkondensatoren IDCs für Hochleistungsanwendungen werden dargelegt. Design-Leitfäden werden für den Entwurf im Hochleistungsbetrieb aufgezeigt. Die untersuchten Komponenten werden als Teil eines kompakten, steuerbaren Anpassnetzwerks zusammen mit einem GaN HEM Transistor implementiert. Der somit steuerbare Verstärker wird hinsichtlich seiner Eigenschaften eingehend charakterisiert.

The current work aims to contribute to our understanding of mean flow generation mechanisms in rotating fluids. The focus is on the mean flow generation mechanisms by: 1) centrifugally unstable Görtler vortices and 2) resonant excitation of inertial waves in a stable regime. Direct numerical simulations (DNS) of the fluid flow in a rotating annular container with longitudinally librating walls are used to investigate the mechanisms.Longitudinal libration of the cylinder side walls of an annulus induces in a supercritical regime an unstable Stokes boundary layer which generates Görtler vortices in a portion of a libration cycle, as a discrete event. DNS results show that these vortices propagate into the fluid bulk and generate an azimuthal mean flow. Reynolds-averaged Navier¿Stokes (RANS) equations are used as a diagnostic tool to investigate generation mechanism of the azimuthal mean flow in the bulk. First, we explain, phenomenologically, how absolute angular momentum of the bulk flow is mixed and changed due to propagation of the Görtler vortices, causing a new vortex of basin scale size. Then we investigate the RANS equations for an intermediate time scale of the development of the Görtler vortices, and for a long time scale of the order of several libration periods. The former exhibits sign selection of the azimuthal mean flow. Investigating the latter, we predict that the azimuthal mean flow is proportional to the libration amplitude squared and to the inverse square root of the Ekman number and libration frequency. We confirm this using the numerical data. Additionally, presence of an upscale cascade of energy is shown, using kinetic energy budget of fluctuating flow.In the second part of the current study, we investigate the mean flow generation mechanism by intrinsic nonlinearity of the inertial wave beams and normal modes in a rotating annular cavity with longitudinally librating top and bottom lids in a stable regime. We confirm the generation of progressive inertial waves as localized shear layer and normal modes as standing waves at and close to the resonance frequencies. We focus on the low order inertial normal modes. Using the DNS results, we show that when the low order normal modes are excited, a non-geostrophic azimuthal mean flow is generated in the bulk. Following Tilgner (2007) and using analytical and DNS solutions, we identify the source terms responsible for generation of the azimuthal mean flow. We show that helical property of the inertial waves and normal modes causes the source terms. Using the analytical solution, we separate the inertial wave beams from the DNS solution. We show that at and close to the resonance frequency, libration phase of the normal modes is always following that of the inertial wave beam, and their phase lag depends on the libration frequency. Analogy to classical mechanics is commented. Generation efficiency of the mean flow is discussed with respect to the phase lag. Additionally, we address wave-wave and wave-boundary layer interactions, and dependency of the mean flow on the dimensionless parameters.We show that the results obtained are valid for small inclination of the inner cylinder side wall.

In dieser Arbeit werden verschiedene Prozesse zu Biomassetrocknung für die anschließende Mitverbrennung in kohlebefeuerten Dampfkraftwerken untersucht. Modelle der verschiedenen Trocknungsprozesse, sowie Modelle des Dampferzeugers und des Gesamtprozesses werden erstellt, um die Auswirkungen der Biomassemitverbrennung auf den Kraftwerksprozess zu untersuchen. Mehrere Szenarien für die dezentrale und prozessintegrierte Trocknung werden analysiert und bewertet.In this work, several processes for biomass drying for biomass co firing in coal fired steam power plants are evaluated. Models are developed for each drying process, as well as for the power plant boiler and the overall power generation process, to analyse the consequences and impacts of biomass co firing on the power generation process. Several scenarios for decentralised and process integrated drying are analysed and evaluated.

The dissertation consists of three empirical studies and takes a closer look at price fluctuations using German gasoline prices as an example for a homogenous good. It analyzes consumers¿ reaction to price fluctuations and respectively the pricing behavior of firms. The first paper, which was developed with co-authorship, explores consumers¿ online price search effects on the pricing behavior of firms (gasoline price level and price dispersion). As regulators have recently implemented a mechanism for reporting all price changes to a central data base, the core assumption of this price reporting scheme is that the increase in price transparency will lead to a decline in the price level and a reduction in price dispersion. The second study addresses the question whether German gas stations adjust their retail prices asymmetrically in response to crude oil price changes, i.e., whether gas stations react quicker to crude oil price increases than to crude oil price decreases. The third study aims to analyze whether consumers react more strongly to gasoline price increases or to price decreases when considering buying a new vehicle.

Superconductor insulator superconductor (SIS) mixers are used in heterodyne receivers for radio-astronomical observations. The high frequency resolution of the heterodyne technique combined with the high sensitivity of SIS mixers enables high resolution spectroscopy of the interstellar medium.This work focuses on the development of a novel superconductor insulator superconductor (SIS) mixer technology for 800 GHz that could in the future be used up to 1.1 THz. This is an important part of the THz spectrum that is still accessible for astronomy from ground based observatories. Compared to the existing mixers in this frequency regime the sensitivity shall be improved by the use of fully superconducting radio-frequency (RF) matching circuits. The main innovation in this work is the inclusion of an energy relaxation layer made of gold that enables the use of these fully superconducting RF circuits in combination with the mature niobium SIS junction technology. The energy relaxation layer prevents heating of the SIS junction due to Andreev re¿ection at the interface between the junction electrode and the matching circuit transmission line which was observed in earlier developments. This work includes the development of a fabrication process as well as extensive DC and RF measurements and their interpretation.

Der Wnt Signalweg stellt ein zentrales Regulationselement während der Embryonalentwicklung und in adulten Homöostaseprozessen dar, dessen Fehlregulierung eine wichtige Rolle in verschiedensten Krankheitsstadien spielt. LRP6 ist ein singelpass Transmembran-rezeptor, der zur Familie der Lipoproteinrezeptoren gehört und der innerhalb des Wnt/¿-Catenin Signalweges als Korezeptor agiert. Die Bindung sekretierter Wnt Liganden an die extrazellulären Domänen von Frizzled und LRP6 an Empfängerzellen führt zur Aggregation von Rezeptor-Liganden Komplexen in Signalosome. Dies wird begleitet durch Serin/Threonin Phosphorylierung an Konservierten PPPSP und CK1 Motiven der intrazellulären Domäne (ICD) von LRP6, wodurch der intrazelluläre Signalweg aktiviert wird.

The detection of human skin in images is a very desirable feature for applications such as biometric face recognition, which is becoming more frequently used for, e.g., automated border or access control. However, distinguishing real skin from other materials based on imagery captured in the visual spectrum alone and in spite of varying skin types and lighting conditions can be dicult and unreliable. Therefore, spoofing attacks with facial disguises or masks are still a serious problem for state of the art face recognition algorithms.This dissertation presents a novel approach for reliable skin detection based on spectral remission properties in the short-wave infrared (SWIR) spectrum and proposes a cross-modal method that enhances existing solutions for face verification to ensure the authenticity of a face even in the presence of partial disguises or masks. Furthermore, it presents a reference design and the necessary building blocks for an active multispectral camera system that implements this approach, as well as an in-depth evaluation.The system acquires four-band multispectral images within T = 50ms. Using a machine-learning-based classifier, it achieves unprecedented skin detection accuracy, even in the presence of skin-like materials used for spoofing attacks. Paired with a commercial face recognition software, the system successfully rejected all evaluated attempts to counterfeit a foreign face.

The world¿s population presently experiences a period of unprecedented growth, increasing the need to further intensify the agricultural production (Garnett et al.2013). At the same time, recent climate trends and model predictions suggest shifting temperature, precipitation and circulation patterns on global and regional scales (Shepherd 2014). In this context, the risk of temporal or unseasonal drought is increasing in many regions worldwide (Pachauri et al. 2014). Agriculture accounts for about 75 % of human water use (Wallace 2000). However, the availability of water isthe most limiting abiotic factor for plant production (Boyer 1996). Therefore, agricultural production and food security are highly susceptible to increased incidences of drought. Improving the water-use efficiency (WUE) of crop plants and cropping systems is therefore an important strategy to face the current challenges ofglobal change (Pinstrup-Andersen et al. 1999).

The Fifth Veda is an abridged version of Der Fünfte Veda whose latest edition has been published in 2016. The first two chapters and the chapter on the Br¿hm¿ script are almost identical. The investigation of the geo¬metrical signs and of the horse in chapter VII has been added.The English reading is identical with the text in The message of the Indus seals and tablets, whose latest edition appeared in 2016.The master-key of the decipherment in all versions is the discovery of the basic symbolic and linguistic agreement of the Indus inscriptions with the R¿g-Veda. This basic agreement is called the Fifth Veda. It has nothing to do with the Mah¿bh¿rata or the Bh¿gavata Pur¿¿a generally called by this name. There are similarities with the Natya ¿astra, the book dealing with the Indian dance. Its author Bharata is identical to Agni and Rudra-¿iva, that means, the Indian dance originated in the Indus culture.The prototype of a female dancer is the Dawn who a (sacred) prostitute and a loving house-wife as well. Her dance is compared to the move¬ment of the soma-press.

Das Thema dieser Doktorarbeit ist die Reorientierung und Auswertung von vektoriellen Magnetfelddaten, die in zwei Bohrungen während der IODP Expedition 330 zu den Louisville Seamounts aufgezeichnet wurden. Ein Ziel der Expedition war festzustellen, ob sich der Louisville Hotspot relativ zu dem Hawaiian-Emperor Hotspot im Erdmantel bewegt oder ob er stationär ist.Für die Magnetfeldmessungen wurde das Göttinger Bohrlochmagnetometer verwendet, dessen faseroptische Kreisel in der Lage sind, die Drehungen der Sonde im Bohrloch zu bestimmen, wodurch das gemessene Magnetfeld aus dem Bezugssystem der Sonde in das geographische Koordinatensystem reorientiert werden kann.Es werden verschiedene Algorithmen vorgestellt, die auf unterschiedliche Art und Weise die vorhandenen Sensoren kombinieren, um die Daten bestmöglich zu orientieren. Weiterhin werden verschiedene Schichtmodelle verwendet, um die Richtung der Gesteinsmagnetisierung aus den Magnetfelddaten zu bestimmen, wobei auf Uneindeutigkeiten und Messfehler eingegangen wird. Die Ergebnisse dieser Modellierungen unterstützen die Annahme eines stationären Louisville Hotspots.

Public scandals, awareness of food safety of colorants and health promotion are factors that have prompted changes in the legislation of food additives worldwide. Furthermore, the substitution of synthetic with natural food colorants and the importance of finding new sources for natural food colorants have significantly increased.In the first part of this work, the main aim was to characterize the phenolic composition of anthocyanin-rich plant-derived extracts, especially from blackberry, black chokeberry, sour cherry, black carrots, purple sweet potatoes, roselle and butterfly pea. The chemical composition of anthocyanins-rich extracts was obtained by TLC, UV spectra, HPLC-DAD, HPLC ESI-MSn and NMR analysis. In this way, their fingerprints were established in order to be used for routine analytical purposes as well as authenticity control. In the second part, the preparative isolation of anthocyanins by membrane chromatography and countercurrent chromatography was performed. Separation of anthocyanins by both chromatographic techniques was achieved in all cases and allowed isolation of anthocyanin pigments on a large scale in high purity and quantity. On the other hand, countercurrent chromatography, especially LSRCCC, HSCCC and HPCCC provided separation of polyphenols and isolation of individual compounds on a large scale, particularly anthocyanins, chlorogenic acids, quercetin glycosides and kaempferol glycosides.

The present volume draws on the experience of the pan-African conference in Yaoundé in Summer 2015, where young scholars from Cameroon met young and experienced scholars from Germany, Tanzania, Ghana, and Nigeria. They discussed not only their individual research projects, but also their personal writing experience.This volume records some of the conference presentations supplemented by specially commissioned contributions by experienced research partners in the field. It is particularly useful for young scholars who intend to demonstrate their credibility as researchers in their thesis (BA, MA, or PhD) or in their research and grant applications, in national and international networks. The examples of small projects here try to prove and illustrate that every scholar can profit from the international exchange of ideas and research experience.