Bøger udgivet af Cuvillier

Dispersing admixtures play an important role in today¿s concretetechnology. Around eight billion cubic metres of concrete aremade each year and most of it contains dispersing admixtures.These chemical compounds, added at low dosages during concretemixing, make fresh concrete more liquid and improve its workability.A precise way to determine the workability of concrete is to measureits rheological values yield stress and plastic viscosity. Fromready mixed concrete plants and concrete element plants it is knownthat rheological values of mortar and concrete can sometimes varywhen a new cement batch (i.e. a new production date) is used. Theaim of this study is threefold. Firstly, to measure and evaluate theeffect of variations during routine cement production on the rheologyof mortar and concrete. Secondly, to identify the constituentsin cement which lead to fl uctuations in rheology. Thirdly, to quantifythe changes in rheology due to variations in cement properties.These questions are essential for cement and concrete producersto guarantee a homogeneous concrete production, but also for thescientifi c community to reach a deeper understanding of cementadmixtureinteractions.

This work investigates the crystallography and dielectric properties of Zirconium- and Hafnium-oxide based nano-scale thin film insulators for memory.Hafnium- and Zirconium-oxide are industry leading candidates for high-k dielectrics. Most application research has focused on the application of amorphous high-k due to formation of defects associated with the crystalline phase. However the application of crystalline dielectrics offers two advantages: Potentially high thermal stability, since no measures have to be taken to avoid crystallization, and the ability to manipulate crystalline phase composition to maximize dielectric constants.Pure ZrO2 crystallized at a lower temperature than HfO2 and always formed a metastable t¿ higher-k phase. ZrO2 crystallized already during deposition, leading to leakage current degradation. It was shown that this problem could be solved by SiO2 addition to raise the crystallization temperature, allowing fabrication of low leakage, low effective oxide thickness (EOT) metal-insulator-metal (MIM) capacitors suitable for stack based DRAM down to the 4X nm node.

In dieser Dissertation werden Methoden zur Segmentierung anatomischer Strukturen in Planungsbildernder Magnetresonanztomographie (MRT), sogenannten Localizer-Bildern, vorgestellt.Localizer sind schnelle MR-Scanprotokolle zur Untersuchungsplanung. Segmentierungenanatomischer Strukturen aus diesen Bildern können für Anwendungen zur vollautomatischenUntersuchungsplanung, z.B. Organlokalisierungen, Schichtpositionierungen, Sequenzanpassungen,etc. verwendet werden. Da Localizer-Bilder nicht hinsichtlich Bildqualitätsondern hinsichtlich Messzeit und Abdeckung optimiert sind, sind modellbasierte statistischeVerfahren für die Segmentierung vorteilhaft.Zwei Methoden werden vorgestellt: Die erste ist eine Methode zur Rekonstruktion von Leberform,-position und -orientierung aus einer Serie von wenigen 2D-Planungsschichtbildernmit großem Schichtabstand. Dazu wird ein Active Shape Model aus manuellen Lebersegmentierungenvon 3D Trainingsbildern erstellt, das die durchschnittliche Leberform und die Hauptkomponentenseiner Varianz beschreibt. Korrespondierende Landmarkenpunkte auf der Oberfläche werden durch Remeshing mit Hilfe konformer Abbildungen in der sphärischen Domäneinitialisiert und verfeinert durch Optimierung eines Korrespondenzmaßes, welches auf MinimumDescription Length (MDL) basiert und die Kompaktheit des generierten statistischenModells beschreibt. Die Segmentierung der Leber aus den gestapelten 2D-Schichtbildern erfolgtdurch durch die Berechnung derjenigen Modellinstanz des Active Shape Models, welchebestmöglich die Bilddaten beschreibt. Man erreicht dies durch iterative Berechnung optimalerVerschiebungen der Landmarken. Die optimalen Verschiebungen beruhen auf Grauwertprofilenin den Bildern und einer normalisierten lokalen Statistik der Grauwertverteilungen in denTrainingsbildern. Die Instanz des Active Shape Models, die die gefundenen Verschiebungender Landmarken am besten repräsentiert, wird durch eine Projektion auf den Linearraum desActive Shape Models gefunden. Daraus erhält man eine gültige Modellinstanz, die die Verschiebungender Landmarken bestmöglich beschreibt.

The overall goal of this study was to characterize the genetic diversity of the Vietnameselocal chicken breeds and to identify population priorities for conservation. The specificaims were 1) to assess and explain the population genetic structure of the Vietnamesebreeds, 2) to characterize the Vietnamese breeds in relation to the Chinese breeds andwild chickens, 3) to estimate conservation potentials for conservation priorities of theVietnamese breeds, and 4) to define an optimal allocation of limited conservation fundsto them.First genetic diversity within and between the Vietnamese breeds was analysed at theautosomal level using 29 microsatellites. A total of 353 individuals of nine Vietnameselocal breeds and two breeds of Chinese origin were studied. The Vietnamese breeds weresampled from the northern and southern parts of Vietnam while the two Chinese breeds(NIAS Chinese breeds) have been kept at the National Institute of Animal Sciences,Hanoi. The results revealed a high level of diversity within Vietnamese breeds. Analysingthe genetic structure using the software package STRUCTURE suggested an optimalclustering at K = 6. These groups encompassed four homogeneous clusters, one formedby the two Chinese breeds and the other three representing a single breed each: theMekong Delta breed Ac, the South Central Coast breed Choi, and the Red River Deltabreed Dong Tao. The six remaining breeds formed two additional admixed clusters. Thisfinding indicates that sub-structuring of the Vietnamese chicken breeds is related to theirgeographical distribution. The two NIAS Chinese breeds are genetically distinct from theVietnamese breeds.

One challenge for those involved in the life science research, especially bio-physiologicalresearch is the emerging evolution of molecular technology. Advances in genetics andaccumulated information in the genomics have made molecular technology and its application inlife science the fastest growing tools in this millennium. Many Researchers in the developedcountries are very much at home with this advancement and have taken advantage to developtheir research interest and contribute more meaningful to their community. This technology isstill new and just emerging in the developing countries. However, in recent years moleculartechnology tools is fast becoming popular in life science research in the developing world,especially in the field of agriculture, biology, biochemistry, medical science etc. Biotechnologytools are widely available and currently in use as research tools in most developed countries. Thepotentiality of its application in the developing countries, especially Africa has formed themotivation for seeking foreign fellowship on one hand and even returning home after thefellowship on the other hand by many young researchers. Organizing a scientific conference withfocus or emphasis in this evolving area will give opportunity to researchers to take stock of howmuch has been acquired during the period of stay in the developed countries (especiallyGermany) and how much is applicable to research environment in the home country (Nigeria).Three days scientific conference was organized to achieve this goal. The scientific meeting wasdesigned to stimulate collaboration and research interest in the emerging and revolutionary fieldof molecular biology among Humboldtians and other young researchers in Nigeria. The requestfrom the participants and desire to preserve the high quality of papers and amazing scientificinformation presented during this conference motivated the publication of this book. Thegenerosity of Humboldt Foundation to solely support both the conference and publication of thisbook, made possible the realization of our dream.

Spatial correlations are of fundamental importance for many fascinating aspects of solid state physics, such as non-Fermi-liquid behavior, spin fluctuations, high-temperature superconductivity and quantum criticality.The major part of this book is devoted to the dual fermion approach, which combines numerical and field theoretical diagrammatic methods to describe the effects of spatial correlations beyond dynamical mean-field theory (DMFT). The approach is generalized in various respects. It is shown that it has superior convergence properties compared to standard diagrammatic extensions of DMFT and its applicable even in presence of strong interactions. Numerical calculations employ the recently developed continuous-time quantum Monte Carlo methods, which are generalized to compute two-particle correlations functions.These techniques are used to study the two-plane Hubbard model on the Bethe lattice, the spatial correlations around a Kondo impurity and the Hubbard model in finite dimensions. Based on a ladder approximation to the dual-energy, a scheme is proposed which for the first time will allow a realistic and computationally feasible description of strongly correlated materials for which the correlations are manifestly long-ranged.In addition to the key scientific results, this book contains significant introductory materials to the models, methods and concepts used for the theoretical description of quantum many-particle systems. In particular the continuous-time quantum Monte Carlo methods are described in detail and on an elementary level. Providing technical details and complete derivations, this book is meant to help in the implementation of these novel approaches and to serve as an introduction and a reference for students beginning to work in this field.

Wood Polymer Composites are a new group of hybrid materials, which combine the advantagesof synthetic polymers such as polyolefines and natural polymers such as wood; whereas thesynthetic polymer is used as matrix material and the wood as reinforcement material or filler. Asmatrix material, principally every thermoplastic polymer with a processing temperature below200°C can be used due to the temperature sensivity of wood. Wood Polymer Composites areprocessed typically with processing technologies from the plastic industry such as extrusion andinjection molding.The present study was conducted to explore the possibility of wood particle modification withdifferent types of silanes. It was the aim to contribute the silanes as compatibilizers or couplingagent and therefore improve the mechanical properties and the resistance against water. Norwayspruce (Picea abies) as representative wood species was used in three different particle types. Thesize distribution for the wood particles ranges from 70-2500 µm. Four commercial availablesilanes with various functional groups (amino, di-amino, alkyl) were used as modification agents.The concentrations varied between 1.5%, 3.0%, 4.5% and 7.5%. As reference system commonlyused maleated acid anhydride based coupling agents were used. The pre-treated wood particleswere compounded via extrusion with polypropylene and samples were produced via injection andcompression molding. The following properties were tested; tensile, bending, and impactstrength, water uptake (cold and boiling water test), descent rate, weathering tests and durabilitytest against basidiomycetes.

In my thesis, static and dynamic properties of low-dimensional spin models were studied by means of a state of the art QMC method (SSE). As one among many numerical algorithms (e.g. DMRG, ED), the QMC proved to be a very flexible and high performance tool with access to dynamic correlation functions at finite temperatures and finite magnetic fields within the thermodynamic limit1. After detailed introduction of the QMC¿s basic implementation, I provided yet unpublished information about the measurement of transverse (and longitudinal) imaginary time correlation functions for the spin S Heisenberg model. In addition to that, complications of the analytic continuation to the real axis were explained and two common Maximum Entropy algorithms (Bryan and Meshkov) introduced briefly. In my thesis, both algorithms have been implemented and contrasted in regard to their performance and quality of the continuation, clearly favoring Bryan¿s method which is a standard least square algorithm based on Newton iterations with however highly optimized search directions in the multi-dimensional solution space.

The management of knowledge is still marked by a general plurality of perspectives, leading to a multitude of different definitions of knowledge as well as different proposals for models and frameworks, all of which are intertwined with and influenced by a vast collection of academic disciplines. Thus, leaving the isolated usage of single knowledge management methods such as best practices or lessons learned aside, it is almost impossible for practitioners to easily take any existing scientific knowledge management model, transform it in accordance with the single firm?s conditions and then align it with its overall strategic management.This overall state of knowledge management within the literature, as well as the rather confused state amongst practitioners, highly influenced this study. Additionally, given the sometimes fundamental differences between certain industries as well as cultures, it is doubtful that a knowledge management model that claims to be designed for practice can account for all idiosyncrasies in all industries while at the same time spanning cultural differences. Consequently, the research question has to be narrowed down to a single industry (in the case of this study, the financial services sector) as well as a certain region (in the case of this study, German-speaking countries) and is formulated as follows: How can a financial services industry-specific knowledge management model be developed for German-speaking firms and aligned with the overall strategic management that accounts for ever-present market and/or regulatory ¿ and hence strategic ¿ changes?

The creation and development of educational hypermedia by teachersand educational staff is often limited by their lack of computing skills, timeand support from the educational institutions. Especially the lack of computingskills is a hinderance to most of today¿s educational experts. Theproblem is to find out how those educational experts could be supported bycomputer based tools which are tailored especially to their needs withouthaving any technical limitations.In this study the separation of technical and educational content in educationalhypermedia is examined as a solution to this problem. The mainhypothesis of this study is that the separation of technical and educationalcontent is possible if it is based on a fine-grained structure of different teachingand learning strategies and their conversion into an authoring tool. Suchan authoring tool would make the creation of educational hypermedia veryeasy for teachers and therefore enable them to overcome the existing obstacles.The development of a new model, the creation of a new XML languageand the implementation of a new authoring tool form the basis for a detailedinvestigation. The investigation was done by undertaking several researchtasks like the evaluation of the XML language and the authoring tool by agroup of educational experts of different knowledge domains, the practicalusage of the authoring tool for the creation of real-life based educationalmaterial and the analysis of the gained research results.

Eingebettete Systeme, die das Leben sicherer, produktiver und komfortabler machen,werden von Konsumenten in immer stärkerem Maße wertgeschätzt. Viele diesereng mit der Außenwelt interagierenden Systeme zum Beispiel im Automobil bestehenschon heute aus zahlreichen Einzelkomponenten, die gemeinsam die komplexen,oft verteilten Funktionen bereitstellen. Um den wachsenden Rechenanforderungengerecht zu werden und möglichst auch die Anzahl der Recheneinheiten zu reduzieren,sind die einzelnen Komponenten inzwischen selbst komplexe Systeme, bestehend ausmehreren Prozessoren und gemeinsam genutzten Ressourcen. Dieser hierarchischeAufbau führt zu einer nur schwer zu beherrschenden Systemkomplexität.Um dennoch die Produktivität im Entwicklungsprozess und die Sicherheit der ausgeliefertenSysteme zu gewährleisten, werden Methoden benötigt, die über die klassischenVerfahren wie Entwicklung, Simulation und anschließender Fehlersuche hinausgehen.Formale Analysemethoden sind eine ideale Ergänzung um die aufkommendenIntegrationsrisiken frühzeitig zu erkennen und zu entschärfen, und um insbesondere insicherheitskritischen Systemen eine Unterdimensionierung von Systemkomponentenzu vermeiden, die zu einer Verletzung von zeitlichen Anforderungen führen würde.In dieser Arbeit begegnen wir den Herausforderungen bestehender und zukünftigerSystemarchitekturen mit einer formalen Methode zur Performanzanalyse.Dabei liegt der Fokus zunächst auf der Analyse der verteilten Funktionen, indem auchetablierte Performanz-Indikatoren erneut untersucht werden. Es werden neue Methodeneingeführt, um das zeitlich verzerrte Verhalten von Ereignissen entlang einerTask-Kette zu untersuchen und um die Antwortzeiten der Tasks und die Gesamt-Latenz entlang einer Kette zu bestimmen. Diese Methoden basieren auf einem neuenModell des Zeitverhaltens eines einzelnen Tasks, das sehr effizient die nötigen zeitlichenEigenschaften abstrahiert und diese für die System-Analyse zur Verfügungstellt. Zusammen mit einer verallgemeinerten Betrachtung von Event-Modellen, dieauch spezielle Charakteristika wie periodische Bursts erfasst, führen diese Methodenzu sehr präzisen Ergebnissen ohne Effizienz einzubüßen.Die wachsenden Berechnungs- und Sicherheitsanforderungen führen auch in SteuerdominiertenSystemen vermehrt zum Einsatz von Multicore-Controllern.

In this thesis, a coupled multiphysical system is considered, whereas the focus is upon aeroelastic problems. For a consistent formulation of such coupled systems, an energy based variational formulation is chosen to describe initially the structural and ¿uid subsystem by Hamilton¿s principle. Both basic ¿uid model equations ¿ inviscid and viscous ¿uid models ¿ are employed by this weak variational energy principle. This procedure allows to describe the coupled problem by the classical direct two-¿eld approach as well as by a novel indirect three-¿eld approach.To discretize the entire system consistently with ¿nite elements, the CBS scheme is employed for the ¿uid domain described by the Navier-Stokes equation in ALE frame of reference. This allows the ¿uid domain to be temporally deformable, which is essential for aeroelastic computations. The CBS scheme is veri¿ed for a wide range of typical ¿uid problems ranging from inviscid, viscous, incompressible and turbulent ¿ows. A good agreement with data published in literature and with the further solver TAU are found, which underlines the applicability of the CBS scheme for di¿erent ¿uid ¿ow models.The DG-CBS scheme as a novel and attractive approach has been derived from the continuous version. One important advantage of the DG version is the design of the element edge ¿ux to be locally conservative. For the example of the laminar ¿ow over the NACA0012 airfoil as well as for the panel ¿utter problem, a comparison of the CBS and DG-CBS scheme is made on structured ¿uid grids including grid convergence studies. With biquadratic, more accurate results in terms of the ¿utter frequency are obtained with DG-CBS scheme. Moreover, no global system of linear equations needs to be solved at the computational expense of addidtional element edge ¿ux calculations with the DG version. This might be attractive for ¿uid grids with a high number of degrees of freedom.

PLEASURES on the PERIPHERY is a collection of authentic, occasionally surreal observations of life and work in the provinces of Sicily and People¿s Hungary 1966-1970. The narrator was short of money, trying to survive like everyone else, very much out on his own ¿ but through his work in a position to encounter a wide cross-section of society. Twenty years later he was one of a team assisting in the local transition from communism to democracy (¿Hello What?¿) in the distant south of Hungary, supported by an EC grant. The concept of ¿socialism with a human face¿ pervades many of the descriptions included in this book and acts as a recurrent theme in its vignettes.The book includes a number of original photographs, and begins and ends with excursions to two non-peripheral places, London and the cloudy south-west of Poland.