To see the other types of publications on this topic, follow the link: Christoffel.
Dissertations / Theses on the topic 'Christoffel'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Christoffel.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Tarsissi, Lama. "Balance properties on Christoffel words and applications." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAM097/document.
Full textAbstract:
De nombreux chercheurs se sont intéressés à la Combinatoire des mots aussi bien d'un point de vue théorique que pratique. Pendant plus de $100$ ans de recherche, de nombreuses familles de mots ont été découvertes, certaines sont infinies et d'autres sont finies. Dans cette thèse, on s'intéresse aux mots de Christoffel. On aborde aussi les mots de Lyndon et les mots Strumians standards. Dans cette thèse, nous donnons de nombreuses propriétés sur les mots de Christoffel et on approfondit l'étude de la notion d'équilibre. Il est connu que les mots de Christoffel sont des mots équilibrés sur un alphabet binaire et sont formés par la discrétisation de segments de droite de pente rationnelle. Les mots de Christoffel sont aussi retrouvés dans l'étude de la synchronisation de k processus dirigé par k mots équilibrés. Pour k=2, on retombe sur les mots de Christoffel, tandis que pour k>2, la situation est plus compliquée et nous amène à la conjecture de Fraenkel qui est ouverte depuis plus de 40 ans. Comme c'est difficile d'atteindre cette conjecture, alors nous avons cherché à construire des outils qui nous aide à s'approcher de cette conjecture. On introduit ainsi la matrice d'équilibre B_w où w est un mot de Christoffel et la valeur maximale de cette matrice est l'ordre d'équilibre du mot binaire utilisé. Comme les mots de Christoffel sont équilibrés alors la valeur maximale dans ce cas là sera égale à 1 et chaque ligne de cette matrice sera formée des mots binaires. Cela nous pousse à tester de nouveau l'ordre d'équilibre de chaque mot obtenu et une nouvelle matrice est obtenue qui s'appelle matrice d'équilibre du second ordre . Cette matrice admet de plusieurs propriétés et de symétries et a une forme particulière comme on est capable de la partager en $9$ blocs où c'est suffisant de savoir 3 parmi eux pour construire le reste. Ces trois blocs correspondent à des matrices de mots de Christoffel qui se trouvent dans des niveaux plus proches de la racine de l'arbre des mots de Christoffel. La valeur maximale de cette nouvelle matrice U_w est appelée équilibre du second ordre. En regardant les chemins qui minimisent cette valeur tout au long de l'arbre, on remarque que le chemin suivi par les fractions obtenues du rapport des nombres consécutifs de la suite de Fibonacci, appelé chemin de Zig-zag est l'un des chemins minimaux. On retrouve ces chemins géométriquement sur le chemin de Christoffel en introduisant une nouvelle factorisation pour les mots de Christoffel appelée la factorisation standard symétrique. Nous avons, également, pu trouver une relation directe entre la matrice U_w et le mot de Christoffel initial sans passer par la matrice B_w et cela en étudiant l'ensemble des vecteurs abéliens associés. Tout ce travail nous a permis de réfléchir au sujet initial qui est la synchronisation de k mots équilibrés. Ainsi, pour le cas de 3 générateurs, nous avons pu étudier tous les cas possibles de la synchronisation et une discussion bien détaillée est faite en utilisant un nouvel élément appelé la graine qui est la première colonne de la matrice de synchronisation. La matrice du second ordre d'équilibre, avec toutes ses propriétés va être un bon outil pour étudier la synchronisation de k générateurs et cela constitut mon projet de recherche dans le futur. Nous avons aussi utilisé toutes nos connaissances autour des mots de Christoffel pour avancer dans la reconstruction de polyominoes convexes. Comme le contour d'un tel polyomino est formé des mots de Christoffel de pentes décroissantes, on a introduit un nouvel opérateur qui modifie ce chemin tout en gardant la décroissance des pentes c'est-à-dire en conservant la convexité qui est un premier pas vers la reconstructionMany researchers have been interested in studying Combinatorics on Words in theoretical andpractical points of view. Many families of words appeared during these years of research some ofthem are infinite and others are finite. In this thesis, we are interested in Christoffel words andwe introduce the Lyndon words and Standard sturmian words. We give numerous properties forthis type of words and we stress on the main one which is the order of balancedness. Well, itis known that Christoffel words are balanced words on two letters alphabet, where these wordsare exactly the discretization of line segments of rational slope. Christoffel words are consideredalso in the topic of synchronization of k process by a word on a k letter alphabet with a balanceproperty in each letter. For k = 2, we retrieve the usual Christoffel words. While for k > 2, thesituation is more complicated and lead to the Fraenkel’s conjecture that is an open conjecturefor more than 40 years. Since it is not easy to solve this conjecture, we were interested in findingsome tools that get us close to this conjecture. A balance matrix B w is introduced, where wis a Christoffel word, and the maximal value of this matrix is the order of balancedness of thebinary word. Since Christoffel words are one balanced then the maximal value obtained in thismatrix is equal to 1 and all the rows of this matrix is made of binary words. Testing again thebalancedness of these rows, a new matrix arises, called second order balance matrix. This matrixhas lot of characteristics and many symmetries and specially the way it is constructed since it ismade of 9 blocks where three of them belong to some particular Christoffel words appearing insome levels closer to the root of the Christoffel tree. The maximal value of this matrix is calledthe second order of balancedness for Christoffel words. From this matrix and this new orderof balancedness, we were able to show that the path followed by the fractions obtained fromthe ratio of the consecutive elements of Fibonacci sequence is a minimal path in the growth ofthis second order. In addition to that, these blocks are geometrically found on the Christoffelpath, by introducing a new factorization for the Christoffel words, called Symmetric standardfactorization. Similarly, we worked on finding a direct relation between the second order balancematrix U w and the initial Christoffel word without passing by the balance matrix B w but bystudying the set of factors of abelian vectors. All this work allow us to think about the initialtopic of research which is the synchronization of k balanced words. A complete study for the casek = 3 is given and we have discussed all the possible sub-cases for the synchronization by givingits seed, which is the starting column of the synchronized matrix. The second order balancematrix, with all its properties and decompositions form a good tool to study the synchronizationfor k generators that will be my future project of research. We have tried to use all the knowledgewe apply them on the reconstruction of digital convex polyominoes. Since the boundary wordof the digital convex polyominoe is made of Christoffel words with decreasing slopes. Hencewe introduce a split operator that respects the decreasing order of the slopes and therefore theconvexity is always conserved that is the first step toward the reconstruction
2
Pasquel, Carbajal Francisco. "Tensor de Riemann-Christoffel." Pontificia Universidad Católica del Perú, 2014. http://repositorio.pucp.edu.pe/index/handle/123456789/95318.
Full textAbstract:
Se presentan algunos conceptos básicos tensoriales, junto con el desarrollo de una forma práctica del tensor de curvatura de Riemann-Christoffel, tensor que es de mucha utilidad en diferentes aplicaciones.
3
Pretorius, Christoffel Cornelius Jacobus. "Selfbeeld van die hulpklasleerling / Christoffel Cornelius Jacobus Pretorius." Thesis, Potchefstroom University for Christian Higher Education, 1988. http://hdl.handle.net/10394/8146.
Full textAbstract:
The purpose of this study is to determine whether a child with specific learning disabilities also experiences emotional problems like a poor selfimage. Special reference is made to the aid class pupil.
Theoretical background knowledge of the child with specific learning disabilities has been compiled: the etiology and manilestation of learning problems as well as certain characteristic behaviour patterns of such a child. The concept of selfimage and factors that influence it have been attended to. The function and purpose of the aid class have also been dealt with. The questionnaire as emperical research method is explained and
implemented in this study. Questions drawn from the above-mentioned study of literature formed the basis of the questionnaire. Questionnaires were sent to everyone of the Afrikaans speaking aid class teachers in Transvaal, totalling a number of 120. The data collected from the questionnaires returned, was analised by means of the S.A.S. computer programme. It is very clear form the frequency and percentage tables compiled from the data analysis, that most aid class pupils have a poor self-image. The questionnaire confirmed what was indicated in the literature: perceptual and academic problems, certain behaviour patterns and the bearing of these factors on the self-image of the pupil in the aid class. Likewise, similar confirmation was obtained concerning the influence of the home and school on the self-image of such a child. It can thus be stated from the study undertaken that an adequate selfimage is a pre-requisite for optimal learning and the actualisation of potential. For this reason the initial orthodidactical assistance to the aid class pupil should include the acquirement of a positive self-image in order to have the child affectively and emotionally prepared in a sufficient way for the intensified leaming process in the aid class.Skripsie (MEd)--PU vir CHO, 1989
4
Brewis, Marthinus Christoffel. "Onderhoudvaardighede by beroepsleiding aan skoolverlaters / Marthinus Christoffel Brewis." Thesis, Potchefstroom University for Christian Higher Education, 1985. http://hdl.handle.net/10394/9355.
Full textAbstract:
Perception and inquiries have revealed that not all vocational guidance
teachers possess the necessary interviewing skills.
The aim of the research was to identify generally applicable interviewing
skills, as well as those specific interviewing skills which are characteristic
of the vocational guidance provided to a pupil leaving school.
The aim was furthermore to determine to what extent vocational guidance
teachers in Transvaal secondary schools are grounded in these skills.
It has been indicated that vocational guidance actually culminate in the
interview. After the interview has been analysed from an educational
perspective, attention has been given to the validity and reliability of
the interview. Further attention has been given to the trainability in
interviewing of vocational guidance teachers.
The following most important, generally applicable interviewing skills were
then identified.
* Communication as interviewing skill - There is a distinction between verbal and non-verbal communication.
* Listening as interviewing skill - A distinction is drawn between marginal listening, evaluative listening and projective listening.
* Establishment of report as interviewing skill - A favourable emotional climate is a requirement for a successful interview.
* "Silence" as interviewing skill - The following distinction applies: that between silence initiated by the interviewer, and silence initiated by the client.
* Perception as interviewing skill - For the interviewer to correctly interpret that which he percepts is equally important, if not more important, than sensory perception.
* Empathy as interviewing skill - It is essential for the interviewer to place himself in the position of the client without becoming emotionally involved.
* Attitude as interviewing skill - Success will be determined by the interviewer's attitude towards the client.
* Questioning as interviewing skill - There is a distinction between an openended and closed question. Questions should be put with utmost circumspection because it could influence the outcome of the interview.
* The use of synopsis as interviewing skill - Through synopsis the client gets the opportunity to verify the information revealed to the interviewer.
The specific interviewing skill characteristic to the vocational guidance situation has been identified as:
The skilful interpretation of reports.
The vocational guidance teacher has a lot of information about the school
leaver from the guardian's file, accumulative card and vocational guidance
file.
The planning and application of an empirical research has been done.
The research was mainly aimed at determining how important the vocational
guidance teachers regard the interviewing skills and to what extent these
teachers are grounded in interviewing skills.
From the research it seemed that the training vocational guidance teachers
received in interviewing, was inadequate.
The most important conclusions were:
* The importance of these interviewing skills to the interviewer
can't be stressed enough.
* The majority of vocational guidance teachers don't possess the
basic qualifications to act as such.
* Some vocational guidance teachers tend to underestimate the
importance of the interviewing skills and they furthermore don't have
the ability to handle• these interviewing skills adequately.
The most important recommendations are:
* That high priority be given to the training of interviewing skills
to vocational guidance teachers.
* That the Transvaal Education Department only appoint qualified vocational guidance teachers at secondary schools.
* That attention should be given to the practical exercise of these skills.
* That universities, in co-operation with the Transvaal Education
Department present further courses in interviewing to acting vocational
guidance teachers.Thesis (MEd)--PU vir CHO, 1986
5
Lombard, Christoffel Jacobus. "Verbruikersopvoeding as komponent van lewensopvoeding / Christoffel Jacobus Lombard." Thesis, Potchefstroom University for Christian Higher Education, 1994. http://hdl.handle.net/10394/9371.
Full textAbstract:
Consumer education as component of the Life Skill education
programme in Guidance:
Consumers are often deprived of their consumer rights. As a
result of drastic changes in society and the market it has
become more important to educate young consumers (at secondary
level) regarding important consumer issues which have an effect
on their daily lives. It is of great importance that the need
for consumer education as part of the secondary school's
guidance programme must be identified and recommendations in
this regard should be made. In the course of this study several
problem areas were identified. The researcher will endeavour to
outline certain findings and make relevant recommendations in
this regard.
The objectives of this study intend to determine what has
actually been done to implement consumer education at secondary
level and if there is an existing need for secondary school
consumer education. In order to obtain data available on the
topic, a questionnaire was used for empirical research. It
provided information regarding aspects of consumer knowledge,
consumer behaviour and consumer rights. Demographic data for
the representation of consumer groups questioned in this
research was compiled, and std. 7 pupils representing the major
population groups, Whites, Blacks, Indians and Coloureds, were
all included in this survey. Scholars were addressed in
Afrikaans and English.
The majority of respondents emphasised the need for consumer
education by indicating that consumer education as part of life
skills could help all consumers. The majority of pupils indicated
that children should have consumer rights and they would
want to learn more about these rights. The majority of
respondents were of the opinion that the school's guidance
programme should include consumer education to make them more
knowledgeable consumers. This study concludes with some
recommendations.Thesis (MEd (Voorligting))--PU vir CHO, 1995
6
Lasnier, Alexandre. "Nombres de Markoff et catégories inclinées amassées." Thèse, Université de Sherbrooke, 2012. http://hdl.handle.net/11143/6554.
Full textAbstract:
On introduit une famille de modules, appelés modules de Marlcoff, engendrée par un procédé itératif semblable à la mutation des objects inclinants dans une catégorie amassée. On montre que ces modules ont une structure combinatoire similaire à celle des mots de Christoffel. En outre, on construit une bijection entre l'ensemble des triplets de modules de Markoff et l'ensemble des triplets de Markoff propres. Ceci nous permet de reformuler la conjecture d'unicité des nombres de Markoff dans un cadre algébrique. Dans la deuxième partie, on étudie les dimensions projectives de la restriction des foncteurs [Special characters omitted.] HomC (-, X ) à une sous-catégorie contravariantement finie et rigide d'une catégorie triangulée [Special characters omitted.] C . On montre que la dimension projective de [Special characters omitted.] HomC (-, X )[Special characters omitted.] T est au plus un si et seulement si il n'existe aucun morphisme non nul entre objets de [Special characters omitted.] T [1] qui se factorise par X , lorsque X appartient à une certaine sous-catégorie convenable de [Special characters omitted.] C . Par conséquent, on obtient une caractérisation des objets de dimension projective infinie dans la catégorie des foncteurs contravariants de présentation finie sur une sous-catégorie inclinante amassée de [Special characters omitted.] C . [symboles non conformes]
7
Laurier, Eric. "Additions et multiplications par un entier de mots de Christoffel." Limoges, 1995. http://www.theses.fr/1995LIMO0011.
Full textAbstract:
Un mot de christoffel fini de pente rationnelle r est une suite finie de 0 et de 1 construite a partir de la fraction continue de r: les mots de christoffel infinis sont les mots de pente reelle construits par le meme procede. Nous decrivons des algorithmes permettant de calculer le mot de christoffel dont la pente est la somme de celles de deux mots donnes ou bien celle d'un autre mot multipliee par un entier. Etant donne le lien fort entre les fractions continues et les mots de christoffel l'interet de ces algorithmes est de mieux comprendre le mecanisme des operations correspondantes sur les fractions continues. De tels algorithmes existent deja pour les fractions continues: la nouveaute est ici l'utilisation des mots de christoffel qui en permet une nouvelle interpretation. Les mots de christoffel peuvent etre definis de plusieurs facons: de maniere geometrique, recursive ou par le biais des mots de lyndon. L'algorithme d'addition utilise une fonction recursive: on construit une suite de mots de lyndon dont le dernier terme est le mot de christoffel. La multiplication consiste en la recherche de formules de recurrence, ainsi ces algorithmes fournissent une conception geometrique et arborescente des nombres et des fractions continues. L'interet de ces algorithmes est theorique ; ils sont avant tout une description des operations sur les fractions continues, au profit de laquelle a ete negligee la rapidite. C'est un point de depart pour trouver d'autres algorithmes plus performants utilisant les mots de christoffel comme nouvelle representation des nombres
8
Lanz, Colleen B. "The Use of Schwarz-Christoffel Transformations in Determining Acoustic Resonances." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/33933.
Full textAbstract:
In this thesis, we set out to provide an enhanced set of techniques for determining the eigenvalues of the Laplacian in polygonal domains. Currently, finite-element methods provide a numerical means by which we can approximate these eigenvalues with ease. However, we would like a more analytic method which may allow us to avoid a basic parameter sweep in finite-element software such as COMSOL to determine what could possibly be an "optimal" distribution of eigenvalues.
The hope is that this would allow us to draw conclusions about the acoustic quality of a pentagonally-shaped room. First, we find the eigenvalues using a common finite-element method through COMSOL Multiphysics. We then examine another method which makes use of conformal maps and Schwarz-Christoffel transformations with the prospect that it might provide a more analytic understanding of the calculation of these eigenvalues and possibly allow for variation of certain parameters. This method, as far as we could find, had not yet been developed on the pentagon. We end up carrying this method through nearly all of the steps necessary in finding these eigenvalues. We find that the finite-element method is not only easier to use, but is also more efficient in terms of computing power.Master of Science
9
Christoffel, Ilya [Verfasser]. "Charakterisierung molekularer und elektrophysiologischer Effekte von Protamin an Nierenepithelzellen / Ilya Christoffel." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2013. http://d-nb.info/1035182432/34.
Full text
10
Lévesque-Gravel, Anick. "Adaptation de la formule de Schwarz-Christoffel aux domaines multiplement connexes." Master's thesis, Université Laval, 2015. http://hdl.handle.net/20.500.11794/26169.
Full textAbstract:
Tableau d'honneur de la Faculté des études supérieures et postdoctorales, 2015-2016La formule de Schwarz–Christoffel permet de trouver une transformation conforme entre un domaine polygonal et un disque. Par contre, cette formule ne s’applique qu’aux domaines simplement connexes. Récemment, Darren Crowdy a obtenu une généralisation de cette formule pour les domaines multiplement connexes. Celle-ci envoie des domaines circulaires sur des domaines polygonaux. Ce mémoire vise à faire la démonstration de la formule développée par Crowdy. Pour ce faire, il faudra définir la fonction de Schottky–Klein ainsi que la fonction de Green modifiée. Il faudra aussi introduire les domaines canoniques.
11
Velozo, Fabricio Santos. "Implementação de um algoritmo numérico para solução da equação de Christoffel generalizada em acustoelasticidade." Universidade do Estado do Rio de Janeiro, 2012. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=4558.
Full textAbstract:
Extensos estudos realizados nas últimas décadas sobre a propagação de ondas ultrassônicas em sólidos levaram ao desenvolvimento de técnicas não destrutivas para a avaliação da segurança e integridade de estruturas e componentes industriais. O interesse na aplicação de técnicas ultrassônicas para medição de tensões aplicadas e residuais decorre da mudança mensurável da velocidade das ondas ultrassônicas na presença de um campo de tensões, fenômeno conhecido como efeito acustoelástico. Uma teoria de acustoelasticidade fornece um meio atrativo e não destrutivo de medir a tensão média ao longo do caminho percorrido pela onda. O estudo da propagação das ondas ultrassônicas em meios homogêneos anisotrópicos sob tensão conduz a um problema não linear de autovalores dado pela equação de Christoffel generalizada. A característica não linear deste problema decorre da interdependência entre as constantes elásticas efetivas do material e as tensões atuantes. A medição experimental de tensões por técnicas ultrassônicas é um problema inverso da acustoelasticidade. Esta dissertação apresenta a implementação de um algoritmo numérico, baseado no método proposto por Degtyar e Rokhlin, para solução do problema inverso da acustoelasticidade em sólidos ortotrópicos sujeitos a um estado plano de tensões. A solução da equação de Christoffel generalizada apresenta dificuldades de natureza numérica e prática. A estabilidade e a precisão do algoritmo desenvolvido, bem como a influência das incertezas na medição experimental das velocidades das ondas ultrassônicas, foram então investigadas. Dados sintéticos para as velocidades das ondas ultrassônicas de incidência oblíqua em uma placa sujeita a um estado plano de tensões foram gerados pela solução direta da equação de Christoffel generalizada para ilustrar a aplicação do algoritmo desenvolvido. O objetivo maior desta dissertação é a disponibilização de uma nova ferramenta de cálculo para suporte às atividades experimentais de medição de tensões por ultrassom no país.Extensive studies carried out in the last decades on the propagation of ultrasonic waves in solids led to the development of nondestructive techniques for the assessment of the safety and integrity of industrial structures and components. The interest in the application of ultrasound techniques for stress measurement for example comes from the measurable change in the speed of the ultrasonic elastic waves in the presence of a stress field, a phenomenon known as acoustoelastic effect. An acoustoelastic theory provides an attractive way of non-destructively measuring the average stress along the waves path. The study of the propagation of ultrasonic waves in homogenous anisotropic bodies under stress leads to a nonlinear eigenvalue problem given by the generalized Christoffel equation. The nonlinearity characteristic of the problem derives from the interdependence between the materials effective elastic constants and the acting stresses. The experimental measurement of stresses using ultrasound techniques is an inverse problem of acoustoelasticity. This dissertation presents the implementation of a numeric algorithm, based on the method proposed by Degtyar and Rokhlin, for solution of the inverse problem of acoustoelasticity in orthotropic solids subjected to a plane stress state. The solution of the generalized Christoffel equation poses difficulties of numerical and practical order. The stability and precision of the algorithm developed, as well as the influence of the experimental uncertainties in the measurement of the speed of the ultrasonic waves, were thus investigated. Synthetic data for the speeds of ultrasonic waves of oblique incidence in a plane-stress plate were generated to illustrate the application of the algorithm developed. The main objective of this dissertation is to make available in the country a new numerical tool to support the use of ultrasonic waves for experimental stress analysis.
12
Van, Dijk Christoffel. "Raw materials inventory management for a Coke plant / by Christoffel van Dijk." Thesis, North-West University, 2005. http://hdl.handle.net/10394/2453.
Full text
13
Banjai, Lehel. "Computation of conformal maps by fast multipole method accelerated Schwarz-Christoffel transformation." Thesis, University of Oxford, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.400550.
Full text
14
Brown, Philip Raymond. "The use of the Schwarz-Christoffel transformation in finite element mesh generation." Thesis, University of Leicester, 1990. http://hdl.handle.net/2381/34749.
Full textAbstract:
This thesis describes a new computer-based method for the generation of finite element meshes. It relies upon the Schwarz-Christoffel transformation, a conformal mapping from conplex variable theory. This mapping is defined and some examples of its use in classical fluid dynamics are given. A practical method for evaluating the parameters defining this transformation is described and emphasis is placed on the efficiency of the solution process in order that coirputer run times may be kept as short as possible. A theorem in Euclidean geometry is stated and proved which links the theory of the Schwarz-Christoffel mapping and the geometrical use to which it is put here. Two such Schwarz-Christoffel transformations are used to construct a mapping between any two polygons. The desirable properties of a finite element mesh are stated and a method is described which atteirpts to generate such a mesh in any sinply-connected two-dimensional region. Numbering of the nodes is an inherent part of the generation scheme, thus ensuring that the optimum bandwidth of the resulting system of linear equations in the analysis phase is obtained. In order to be able to present example meshes, a particular element type, the three-noded triangle, is used and a section describing the enumeration of hexagons, all of whose internal angles are 2n/3, is included. The thesis includes a brief survey of existing methods of two-dimensional mesh generation as well as several example meshes.
15
Swanepoel, Christoffel Bernardus. "Die Kalahari-Doppers : geskiedenis van die Gereformeerde Kerk Ghanzi / Christoffel Bernardus Swanepoel." Thesis, Potchefstroom University for Christian Higher Education, 1985. http://hdl.handle.net/10394/10271.
Full text
16
Findley, Elliot M. "Christoffel function asymptotics and universality for Szego weights in the complex plane." [Tampa, Fla] : University of South Florida, 2009. http://purl.fcla.edu/usf/dc/et/SFE0003047.
Full text
17
Findley, Elliot M. "Christoffel Function Asymptotics and Universality for Szegő Weights in the Complex Plane." Scholar Commons, 2009. https://scholarcommons.usf.edu/etd/1965.
Full textAbstract:
In 1991, A. Máté precisely calculated the first-order asymptotic behavior of the sequence of Christoffel functions associated with Szego measures on the unit circle. Our principal goal is the abstraction of his result in two directions: We compute the translated asymptotics, limn λn(µ, x + a/n), and obtain, as a corollary, a universality limit for the fairly broad class of Szego weights. Finally, we prove Máté’s result for measures supported on smooth curves in the plane. Our proof of the latter derives, in part, from a precise estimate of certain weighted means of the Faber polynomials associated with the support of the measure. Finally, we investigate a variety of applications, including two novel applications to ill-posed problems in Hilbert space and the mean ergodic theorem.
18
Adair, Monte. "Staatsraison bei Grimmelshausen: eine inhaltliche Untersuchung zum Verständnis von Ratio Status als Krisenbegriff des Widerstandes gegen den Absolutismus in Deutschland im 17. Jahrhundert." Magdeburg GAP-Verl, 2007. http://d-nb.info/992687225/04.
Full text
19
Kropf, Everett. "Numerical computation of Schwarz-Christoffel transformations and slit maps for multiply connected domains." Diss., Wichita State University, 2012. http://hdl.handle.net/10057/5361.
Full textAbstract:
Two methods for the numerical conformal mapping of domains with m < ∞ separated
circular holes to domains with m polygonal holes are presented; bounded and unbounded
domains are both considered. The methods are based on extensions of the classical Schwarz-
Christo el transformation to nitely connected domains. The rst method uses a truncated
in nite product expressed in terms of re
ections through circles, and is found to have a
computational time which increases geometrically with the number of levels of re
ection
used. The second method uses the boundary behavior of the map to construct a linear system
which gives the coe cients of a Laurent series expansion for the map. The second method
has a computational time which is polynomial with the number of terms of the truncated
series. Both methods require the solution of a non-linear system of equations which gives the
correct parameters for the desired map. The solution to the non-linear system is achieved
by a numerical continuation (homotopy) method. An application is given. Maps from the
circle domains to the canonical slit domains are also computed using similar techniques.Thesis (Ph.D.)--Wichita State University, College of Liberal Arts and Sciences, Dept. of Mathematics, Statistics and Physics
20
Els, Christoffel Johannes. "Personal archetypes, aspects of personality and psychological well-being / Christoffel Johannes (Christo) Els." Thesis, North-West University, 2004. http://hdl.handle.net/10394/2376.
Full text
21
Smit, Christoffel Andreas. "Die werkstevredenheid van die inspekteur van onderwys in die Noordkaap / Christoffel Andreas Smit." Thesis, Potchefstroom University for Christian Higher Education, 1999. http://hdl.handle.net/10394/8794.
Full textAbstract:
The purpose of this study is to determine the factors that influence the work
satisfaction of inspectors of education in the Northern Cape. This aim is
achieved by firstly conducting a literature study on the nature of work
satisfaction and factors responsible for inspector work satisfaction and/or
work dissatisfaction. Secondly an empirical investigation is conducted on the
perceptions of inspectors about factors influencing their work satisfaction.
Finally, recommendations are made through which inspectors of education
can achieve optimal work satisfaction for themselves.
Findings from the literature study indicate that work context and work contents
factors influence inspector work satisfaction. Work context factors mainly
concern supervision and working conditions. Working conditions include
aspects such as physical working conditions, leadership, interpersonal
relationships, policy, participation in decision-making, salary, work safety,
work security and the organizational climate. Work context factors relate to
inspectors' needs for psychological growth and self-fulfilment viz., the needs
for responsibility, recognition, promotion, the work itself and professional
development.
Findings from the empirical investigation indicate that the respondents are
less satisfied in their jobs than is generally reported. Inspectors regard the
satisfaction of work context factors as very important and are partly
contended that these needs are satisfied. However there are numerous work
context factors from which they derive relatively little work satisfaction, inter
alia, working conditions with regard to some supervisory activities,
participation in decision-making and strategic planning in the department of
education, work security and work safety. The factors within the work
context are experienced as mostly satisfying.
The recommendations of this study emphasise the necessity of an effective
line of communication between the Education Department and the regional
office, and the Education Department should launch a penetrating
investigation into the filling of vacancies at the level of inspectors. With the
aim on participatory management as many as possible role-players should be
involved at provincial level. With the aim of professional development of both
newly appointed inspectors of education and more experienced inspectors of
education a professional inclusion program must be developed regarding
better role and task fulfilment.Thesis (MEd)--PU for CHE, 1999
22
Badenhorst, Christoffel Petrus Stephanus. "Molecular characterisation of a recombinant bovine glycine N-acyltransferase / Christoffel Petrus Stephanus Badenhorst." Thesis, North-West University, 2010. http://hdl.handle.net/10394/9622.
Full textAbstract:
Conjugation of glycine to organic acids is an important detoxification mechanism. Metabolites of
aspirin and industrial solvents, benzoic acid found in plant material and many endogenous
metabolites are detoxified by conjugation to glycine. The enzyme responsible for glycine conjugation,
glycine N-acyltransferase (GL YAT), is investigated in this study. The enzyme is also important for
the management of organic acidemias which are inherited metabolic diseases.
However, not all organic acids can be efficiently detoxified by GL YAT. Consequently, some organic
acidemias, such as propionic acidemia, are difficult to treat. We hypothesise that a novel variant of
GL YAT might be designed that can effectively detoxify propionic acid and several other organic
acids. This novel GL YAT might eventually be used as a recombinant therapeutic enzyme for the
treatment of organic acidemias. A thorough understanding of the mechanisms of substrate binding
and catalysis by the enzyme is needed to design such a novel enzyme. This understanding is
lacking at present. The first step to investigating the mechanics of substrate binding and catalysis is
the development of a recombinant enzyme expression system. Amino acids in the protein can then
be altered using site-directed mutagenesis, to study the importance of individual amino acid residues
to enzyme function. No system for the expression of a biologically active recombinant human GLYAT
has yet been developed. In a recent study in our laboratory, it was shown that bovine GL YAT could
be expressed in a partially soluble and enzymatically active form, using expression at 15 °C and
chaperone co-expression. The enzyme could not be investigated in detail because no tags for
purification were fused to the protein.
In this study the bovine GLYAT was expressed with a C-terminal histidine tag for affinity purification
using the same system. It was confirmed that the recombinant bovine GLYAT was enzymatically
active and it could be partially purified. Two major proteins were present after purification. The
identity of the co-purifying protein is unknown. The enzyme reaction kinetics of the partially purified
recombinant bovine GLYAT and of GLYAT isolated from bovine liver was determined and compared.
The kinetic parameters of the two enzymes were similar and correlated with the values reported in
the literature.
The recombinant bovine GL YAT was used to elucidate the catalytic mechanism of the enzyme. A
putative catalytic residue, E226, was identified on the basis of biochemical arguments and
bioinformatic analyses. This proposed catalytic residue was mutated by means of site-directed
mutagenesis. The E226Q mutant recombinant bovine GLYAT enzyme was compared to the wild
type bovine GL YAT with regard to reaction kinetics and pH dependence of the reaction. The results
suggested that bovine GL YAT uses the E226 residue as a general base catalyst to remove a proton
from glycine in the reaction mechanism. This is the first time a mechanism for GL YAT activity has
been worked out.
Benzoyl-coenzyme A is a substrate of the GLYAT reaction. It is used as a reagent in GLYAT activity
assays and kinetic investigations. Since this compound is very expensive, a method was adapted
from the literature for the cost effective in-house synthesis of this compound. Three biosynthetic
enzymes from Escherichia coli were cloned, sequenced, expressed and purified and then used for
the synthesis of benzoyl-coenzyme A from benzoyl-pantetheine. The conversion from benzoylpantetheine
to benzoyl-coenzyme A was stochiometric. After purification a yield higher than 75%
was obtained. The benzoyl-pantetheine used was first synthesised from benzoic acid and pantethine
by acylation under reducing conditions. All steps could be performed in a single tube. The method
does not require purification of the benzoyl-pantetheine before use in the enzymatic synthesis of
benzoyl-coenzyme A, minimising loss of material.
To summarise, a recombinant bovine GLYAT with a C-terminal histidine tag was expressed and
partially purified. The kinetic properties of the recombinant bovine GL YAT corresponded to the
properties of GLYAT extracted from bovine liver. The recombinant bovine GLYAT was used to
elucidate the catalytic mechanism of GLYAT by means of site-directed mutagenesis. This
demonstrates the power of the recombinant expression system to studying the importance of specific
amino acid residues. Benzoyl-coenzyme A was synthesised using a cost effective method adapted
from the literature. In the future, photoaffinity labelling will be used to identify residues that constitute
the substrate binding site of GL YAT and site-directed mutagenesis will then be used to investigate
their function. It may then become possible to attempt to rationally design a GL YAT with altered
substrate specificity.Thesis (MSc (Biochemistry))--North-West University, Potchefstroom Campus, 2010
23
Lazag, Pierre. "Déformations de Christoffel et loi des grands nombres pour des processus déterminantaux discrets." Thesis, Aix-Marseille, 2020. http://www.theses.fr/2020AIXM0134.
Full textAbstract:
Cette thèse est consacrée à l'étude de certaines propriétés d'exemples de classes de processus déterminantaux. Dans une première partie, nous nous intéressons aux processus déterminantaux reliés aux niveaux de Landau supérieurs du laplacien magnétique dans le disque unité. Nous donnons une estimation précise de la variance asymptotique du nombre de points dans un disque dont le rayon tend vers 1 -. Dans une deuxième partie, nous introduisons les déformations de Christoffel d'ensemble polynômiaux orthogonaux discrets, en multipliant la mesure d'orthogonalité sous-jacente par un polynôme positif. Nous montrons que les déformations de Christoffel de l'ensemble de Charlier convergent vers des déformations du processus de Bessel discret ; nous montrons également que les déformations de Christoffel des z-mesures sont des processus déterminantaux dont nous explicitons le noyau ; enfin, nous établissons que les déformations de Christoffel des z-mesures non-dégénérées convergent vers des déformation du processus avec le noyau Gamma. Dans une dernière partie, nous établissons une loi des grands nombre pour les motifs locaux de partitions planes aléatoires, généralisant à deux dimensions un phénomène apparaissant pour les mesures de Schur unidimensionnellesThis thesis studies several aspects of classes of determinantal processes. In a first part, we introduce determinantal processes arising from the higher Landau levels in the unit disk. We give a precise asymptotic for the variance of the number of points inside a disk of which the radius tends to one -. In a second part, we introduce the Christoffel deformations of discrete orthogonal polynomial ensembles, by multiplying the underlying orthogonality measure by a positive polynomial. We prove that the Christoffel deformatons of the Charlier ensemble converge towards deformations of the discrete Bessel process ; we also establish that Christoffel deformations of the z-measures are determinantal point process with an explicit kernel ; we eventually prove that the Christoffel deformations of the non-degenerate z-measures converge to a modification of the process with the Gamma kernel. In the last part, we establish a law of large numbers for local patterns in random plane partitions, generalizing in dimension two a phenomenon that occurs for a class of one dimensional Schur measures
24
Preller, Abraham Christoffel Naudé. "Numerical modelling of flow through packed beds of uniform spheres / Abraham Christoffel Naudé Preller." Thesis, North-West University, 2011. http://hdl.handle.net/10394/8499.
Full textAbstract:
This study addressed the numerical modelling of flow and diffusion in packed beds of mono-sized
spheres. Comprehensive research was conducted in order to implement various numerical
approaches in explicit1 and implicit2 simulations of flow through packed beds of uniform spheres.
It was noted from literature that the characterization of a packed bed using porosity as the only
geometrical parameter is inadequate (Van Antwerpen, 2009) and is still under much deliberation
due to the lack of understanding of different flow phenomena through packed beds. Explicit
simulations are not only able to give insight into this lack of understanding in fluid mechanics, but
can also be used to develop different flow correlations that can be implemented in implicit type
simulations.
The investigation into the modelling approach using STAR-CCM+®, presented a sound modelling
methodology, capable of producing accurate numerical results. A new contact treatment was
developed in this study that is able to model all the aspects of the contact geometry without
compromising the computational resources. This study also showed, for the first time, that the LES
(large eddy simulation) turbulence model was the only model capable of accurately predicting the
pressure drop for low Reynolds numbers in the transition regime. The adopted modelling approach
was partly validated in an extensive mesh independency test that showed an excellent agreement
between the simulation and the KTA (1981) and Eisfeld and Schnitzlein (2001) correlations'
predicted pressure drop values, deviating by between 0.54% and 3.45% respectively.
This study also showed that explicit simulations are able to accurately model enhanced diffusion
due to turbulent mixing, through packed beds. In the tortuosity study it was found that the tortuosity
calculations were independent of the Reynolds number, and that the newly developed tortuosity
tests were in good agreement with techniques used by Kim en Chen (2006), deviating by between
2.65% and 0.64%.
The results from the TMD (thermal mixing degree) tests showed that there appears to be no explicit
link between the porosity and mixing abilities of the packed beds tested, but this could be attributed
to relatively small bed sizes used and the positioning and size of the warm inlet. A multi-velocity test
showed that the TMD criterion is also independent of the Reynolds number. It was concluded that
the results from the TMD tests indicated that more elaborate packed beds were needed to derive
applicable conclusions from these type of mixing tests. The explicit BETS (braiding effect test section) simulation results confirmed the seemingly irregular
temperature trends that were observed in the experimental data, deviating by between 5.44% and
2.29%. From the detail computational fluid dynamics (CFD) results it was possible to attribute these
irregularities to the positioning of the thermocouples in high temperature gradient areas. The
validation results obtained in the effective thermal conductivity study were in good agreement with
the results of Kgame (2011) when the same fitting techniques were used, deviating by 5.1%. The
results also showed that this fitting technique is highly sensitive for values of the square of the
Pearson product moment correlation coefficient (RSQ) parameter and that the exclusion of the
symmetry planes improved the RSQ results. It was concluded that the introduction of the new
combined coefficient (CC) parameter is more suited for this type of fitting technique than using only
the RSQ parameter.Thesis (M.Ing. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2012
25
Van, der Merwe Hendrik Christoffel. "Chitosan membranes for the removal of zinc from simulated wastewater / Hendrik Christoffel van der Merwe." Thesis, North-West University, 2006. http://hdl.handle.net/10394/1462.
Full text
26
Van, der Walt Petrus Christoffel. "Die identiteit van God se volk in die boek Jesaja / Petrus Christoffel van der Walt." Thesis, North-West University, 2004. http://hdl.handle.net/10394/628.
Full textAbstract:
In the study of the book Isaiah it is apparent that the events in the book can be interpreted as events
before, during and after the exile. Yahwe, the Holy One of Israel, determines the complete process In
the first part of Isaiah (1-39) judgement is passed on the people of God as He makes it clear that He will
destroy them. This judgement is carried out during the exile. However, in the last part of Isaiah (40-66),
a message of hope and new life is brought to Israel. In spite of the destruction of the people of God, they
continue to exist. Therefore the identity of Israel in the beginning of the book differs h m his identity at
the end of the book. An identity model is used to show how old Israel failed in his expected identity as
servant of Yahwe. Yet God brought about a new identity for his people through His perfect Servant.
Through the Servant the relationship between God and His people is repaired, bringing about a new
identity for them. Yahwe gathers the new Israel from all the nations on the globe. He does this through
His Word. The core element of identity is therefore not attachment to a specific nation or country, but a
spiritual bond with God. Through an individual relationship with God believers become part of a
professing society, resulting in a stable identity for the whole community even in an eschatological way.Thesis (Ph.D. (Old Testament))--North-West University, Potchefstroom Campus, 2005.
27
Potgieter, Hendrik Christoffel. "Loopbaanontwikkeling van onderwyspersoneel in die sekondêre skool as taak van die skoolhoof / Hendrik Christoffel Potgieter." Thesis, Potchefstroom University for Christian Higher Education, 1993. http://hdl.handle.net/10394/8626.
Full textAbstract:
The continued development and growth of a teacher is of vital Importance for a
happy and contented school community In which pupils can develop most favourably.
The role a headmaster of a school plays in attaining this, Is essential. The result of
research done on career development of teachers Is resumed in this script.
The nature and the essence of career development are determined through the
definement of the concepts of career, career development and career success. The
importance of career development Is stressed, followed by a discussion on the
different phases of which a career consists. Furthermore it is determined which
Individual characteristics are called upon in a specific job environment and how this
affects a person's choice of career. The essence of the headmaster's Involvement of
the management and. development of the teachers at his school, is described.
Concepts concerning manpower management, the specific function of staff, personnel
management and the control over human resources are discussed. The different ways
In which career development can be approached are discussed as well as the nature of
the headmaster's involvement with the career development of his teachers.
The practice of career development in secondary schools is determined by means of
an empirical research. It is determined which methods and aspects of career development
are most commonly used by headmasters, as well as the Importance of each of
these. Some deficiencies concerning the headmaster's involvement with the career
development of his staff are illuminated through the empirical research.
In conclusion, guidelines are provided which headmasters may use to assist their staff
in the development of their careers. Based on the facts gained through the research
done, a few recommendations are made which headmasters may apply to assist their
staff, in order to promote each and every teacher's career to excellence.Skripsie (MEd)--PU vir CHO, 1994
28
King, A. C. "Application of a generalised Schwarz-Christoffel transformation of some problems of steady free surface flow." Thesis, University of Leeds, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233284.
Full text
29
Pieters, Christoffel Jacobus. "The application of criminal investigations methodology and guidelines in modern day labour related investigations / by Christoffel Pieters." Thesis, North-West University, 2010. http://hdl.handle.net/10394/4737.
Full text
30
Botma, Erasmus Christoffel. "Pastoral guidance for the spiritual development of the adolescents of Little Falls Christian Centre / Erasmus Christoffel Botma." Thesis, North-West University, 2012. http://hdl.handle.net/10394/8573.
Full textAbstract:
Healthy spiritual development of adolescents is lacking in our society. Research shows that the topic of spiritual development for adolescents has been neglected for some time. It is clear from Scripture that spiritual development needs to take place in the life of a believer and that it is in fact an ongoing process. Even though spirituality has not been classified as something scientific during the modern era, spirituality has made its way back in scientific circles. The scientific disciplines of sociology and psychology have indicated that adolescents have a need for spiritual development and that spiritual issues are important to them. However, adolescents of the twenty-first century also face some unique challenges that have an impact on their spiritual development.
Both the quantitative and qualitative methods of research were used and it was clear from both these studies that there were certain areas with regard to spiritual development that needed attention. The results in particular showed that the majority of those adolescents who took part in the research did not spend enough time on spiritual practices and most of them have taken part in some form of risky behaviour. The overall influences from family, friends and youth leaders were positive and in general it seemed that the majority of adolescents who took part in the research had a good relationship with parents and youth leaders.
Adolescents need help in their spiritual development and according to Scripture parents and youth/church leaders have the responsibility to assist them. Guidance was given to adolescents and to major role players in their lives to assist them in the process of spiritual development.Thesis (MA (Pastoral Studies))--North-West University, Potchefstroom Campus, 2013
31
Steenkamp, Johannes Christoffel. "Skakeling tussen sekondêre skool en universiteit met betrekking tot die praktiese onderwys van studente / Johannes Christoffel Steenkamp." Thesis, Potchefstroom University for Christian Higher Education, 1991. http://hdl.handle.net/10394/8597.
Full textAbstract:
Practice teaching (student teaching) is one of the most important components in a student teacher's training programme. It creates a real setting within which the student can experience and realise the theoretical and practical training he has had. Only by bringing-into-practice his theoretical, insight, the student's training truly realises. Practice training at university (the so called institute practicum) is also a valuable training instrument, rut it is not a realistic and complete substitute for practice teaching.
Practice teaching is a means by which the student is professionally and personally orientated for his future career. In the field of his subject he is availed of the opportunity to school himself in the long-term didactical strategies and to practise and put his teaching skills to the test. At the same time he is provided with an opportunity of gaining experience in teacher-pupil relationships, extra-curricular activities, organizational skills, teaching media, etcetera. In addition, practice teaching can also contribute to the shaping and strengthening of the student's Christian philosophy of life.
To get the most out of practice teaching, it is of the essence that the school and university liaise closely with each other. A sound relationship of mutual co-operation must be established and via efficient channels of communication they should strive towards effectively availing each other of information and establishing a mutual understanding.
Liaising, therefore implies a management task which is not only based on a partnership, but also functions on an inter-relatedness with other management tasks. Planning, organization, guidance and control of practice teaching should therefore .be regarded as a concerted management effort by the school as well as the university.
Research has revealed that the above.-mentioned liaising is not quite what it should be. Students are frequently deprived of the opportunity of taking put in experiencing all that the teaching profession has to offer. A good example of this is the fact that in some cases, students are not allowed to set and evaluate tests, do playground duty, nor attend subject and staff meetings. Tutors are frequently totally uninformed about their particular role and task during practice teaching. This almost invariably results in the unprofessional and inefficient guidance of student teachers. Weak liaising between school and university is also reflected by the apparent indifference of certain universities to consult with headmasters as regards the planning and organization of practice teaching.
Conclusively it is clear that meaningful and successful practice teaching is of the utmost importance to the student teacher. The optimal realisation of practice teaching can only take place if the school and the university acknowledge and accept each other as worthy training partners.Skripsie (MEd)--PU vir CHO, 1992
32
Al, Ghabra Mouhammed Anwar. "Géométrie des espaces riemanniens." Mémoire, Université de Sherbrooke, 2017. http://hdl.handle.net/11143/10516.
Full textAbstract:
Dans ce travail, nous présentons une méthode de résolution de l'équation de la courbe géodésique en utilisant le symbole de Christoffel. En effet, l'équation de la courbe géodésique contient une dérivée covariante.
33
Smit, Christoffel Andreas. "Die professionele ontwikkeling van die nuutaangestelde kringbestuurder in die onderwys deur middel van 'n inskakelingsprogram / Christoffel Andreas Smit." Thesis, Potchefstroom University for Christian Higher Education, 2002. http://hdl.handle.net/10394/9969.
Full textAbstract:
This study focuses on the need for an induction programme by which especially
newly appointed circuit managers and circuit managers with little experience
can benefit. This study is not concerned with the training programme for newly
appointed circuit managers, but the emphasis is on the professional induction
and continued development of educational leaders such as circuit managers.
In order to get to the heart of the matter, a literature study was first undertaken
to investigate the nature of professional development of which induction is one
component. Also, problems that might be experienced by circuit managers and
expertise they might need for functioning effectively have been lifted from the
literature study. A few induction programmes in developed and developing
countries have been analysed and compared to practices in the RSA.
Secondly, an empirical study has been undertaken on the perceptions of circuit
managers on problems they are experiencing and on expertise they need in
order to function optimally in their new work environment.
Findings in the literature study reveal that circuit managers experience
distinctive problems, and that these problems manifest themselves within the
circuit managers themselves, in their work environment, on managerial level,
within society and within their careers as educators. Another distinction is that
the managerial skills a circuit manager should have can be divided into four
categories, viz. technical, personal, social and conceptual skills. The literature
study also shows that formal induction in developed countries is run in a
programme-driven manner, while in the RSA there is a lack of formal induction
programmes as well as a formal mentor system for newly appointed circuit
managers.
Findings in the empirical study have shown that respondents experience
serious problems in especially the work environment, on managerial level and
in their teaching careers Less serious problems are experienced in the circuit
manager's personal life and within the community. A further indication was that
respondents considered all the skills as very important in order to function
effectively in their new work environment.
The above needs give rise to the formulation of directives for the development
and implementation of an induction programme for newly appointed circuit
managers. This instruction programme comprises four phases, and the themes
of the respective phases have been selected in such a manner that the
activities in the total induction process are purposeful and orderly, and aimed at
a specific outcome.
Recommendations of this study emphasize the importance of a formal induction
programme as well as a formal monitoring system for newly appointed circuit
managers in die RSA Also, there is an urgent necessity for a formal and
structured job description. ongoing skills development and the
establishment/formulation of a national policy, determining the nature and level
of management training.
Without doubt the most important influence on the quality of circuit managers in
the RSA is their own expertise, and the induction of newly appointed circuit
managers is the sine qua non for the development of competent education
managers.Thesis (Ph.D. (Education))--Potchefstroom University for Christian Higher Education, 2002
34
Fourie, Christoffel Ettienne [Verfasser], Sören [Akademischer Betreuer] Hese, and Feitosa [Akademischer Betreuer] Raul. "Sample supervised search centric approaches in geographic object-based image analysis / Christoffel Ettienne Fourie. Gutachter: Sören Hese ; Feitosa Raul." Jena : Thüringer Universitäts- und Landesbibliothek Jena, 2015. http://d-nb.info/1080521976/34.
Full text
35
Storm, Christoffel Philippus. "A macroscopic determination of the impact of Lethabo coal quality upon the optimum combustion air quantity / Christoffel Philippus Storm." Thesis, Potchefstroom University for Christian Higher Education, 1999. http://hdl.handle.net/10394/7419.
Full textAbstract:
Lethabo Power Station burns a unique low grade coal with low volatile content. This merits the optimisation of the total combustion air quantity with efficiency as main criterion to produce an air flowsteam flow curve as a function of load as well as coal quality. This project demonstrates the optimisation exercise of the unit as a whole, including the boiler as well as the turbine (a 600 MW turbo-alternator set) , therefore producing optimum air flow quantities different to the conventional wisdom. Ninety tests were performed with varying total air flow, at five loads ranging from full load to lowest load with three different coal qualities.
The application of the Station Thermal Efficiency Program (STEP) as optimising tool employs a simultaneous direct and indirect calculation method (opposed to the traditional indirect only methods and programs) . The test results were used to customise the targets of the STEP program for Lethabo as well as to introduce new philosophies in the formulae.
The expected trend of higher unit efficiencies with resulting improved total emissions were confirmed. In the process operational enhancements such as new milling plant settings and sootblowing philosophies were also confirmed to contribute to the improved efficiencies. The findings were operationally implemented which included statutory procedurisation.Thesis (PhD)--PU for CHE, 1999.
36
Meyer, Theunis Christoffel. "Developing a generic model of the initial review process for a gold mine shaft business unit / Theunis Christoffel Meyer." Thesis, North-West University, 2003. http://hdl.handle.net/10394/250.
Full textAbstract:
South Africa is one of the world's foremost mining nations and mining and its associated
industries continue to form the cornerstone of the country's economy. However, the mining
industry has, by its very nature, the potential to endanger human health and safety, as well
as the physical environment. Consequently, mining will always contend with major
environmental challenges and remain under constant public pressure to demonstrate its
commitment to responsible environmental management.
The key to effective environmental management is the use of a systematic approach to plan,
control and improve environmental efforts. An Environmental Management System (EMS)
employs such an approach and allows organisations to address environmental concerns in
an orderly and consistent manner. Such a system allows organisations to anticipate and
meet their environmental objectives and to ensure ongoing compliance with national and/or
international requirements.
An organisation with no existing EMS should, initially, establish its current position with
regard to the environment by means of an initial review process. The aim should be to
consider all environmental aspects of the organisation as a basis for establishing the EMS.
Although a few gold mines in South Africa have implemented an EMS, the question of which
significant environmental aspects need to be managed in such a system at a deep level gold
mine shaft, remains largely unanswered. This study endeavoured to provide answers to this
question and develop a generic model for the initial review process of a deep level gold mine
shaft. The development of such a model should facilitate the development and
implementation of an EMS at such shafts, thereby contributing to reduce the environmental
impact of gold mines.
The research consisted of a literature review of national and international literature on the
topic and a comparative empirical study, which evaluated the mining operations of two deep
level gold mine shafts. Data collection and analysis was done according to the IS0 14015
guideline on the environmental assessment of sites and organisations. Other techniques
used included business process analysis, the use of modified Leopoldt matrices and risk
analysis to determine the significance of the environmental impacts and aspects.
This study contributed to a generic model for the initial environmental review process that
precedes the development of an EMS at deep level gold mine shafts through:
developing a generic sub-model that can be used to determine the scope of any deep
level gold mine shaft;
identifying some of the significant environmental impacts and aspects of deep level gold
mine shafts, as well as
identifying some generic business activities that are potentially destructive and carry a
high risk of causing significant negative environmental impacts.Thesis (M. Environmental Management)--North-West University, Potchefstroom Campus, 2004.
37
Fourie, Christoffel [Verfasser], Sören [Akademischer Betreuer] Hese, and Feitosa [Akademischer Betreuer] Raul. "Sample supervised search centric approaches in geographic object-based image analysis / Christoffel Ettienne Fourie. Gutachter: Sören Hese ; Feitosa Raul." Jena : Thüringer Universitäts- und Landesbibliothek Jena, 2015. http://d-nb.info/1080521976/34.
Full text
38
Van, Aardt Christoffel Carolus. "An investigation of the usage and success of blended e–learning material for computer networking students / by Christoffel van Aardt." Thesis, North-West University, 2010. http://hdl.handle.net/10394/4480.
Full textAbstract:
Students enrolled for the Network Systems III module at the Vaal University of
Technology are experiencing problems with passing this module. Many of them fail
due to the fact that they do not understand the subnet masking part of it. In an
attempt to increase the students' pass rate, this study will make additional study
material available to them, complying with their learning style preferences. This
material will be available as elearning
material on the Internet.
The usage and success of elearning
material implies a holistic approach towards
learning styles. Learning styles consist of different interrelated learning elements.
This study will make use of an action research approach comprising four phases.
In the first phase, different learning styles are diagnosed by means of a literature
study. The information obtained is applied to compile an interpretive questionnaire
for completion by students. This questionnaire will enable the researcher to do an
empirical study with regard to their learning preferences. The data obtained from
the questionnaires will be analysed and information obtained will be applied to
make additional module related elearning
material available on the Internet.
During the second phase, results obtained from the empirical investigation will be
used to develop elearning
material on subnetting, while also addressing the
identified learning styles of participants. The elearning
material is provided on the
Moodle learning management system, enabling students to use it according to their
own preferences.
In the third phase, the success of the intervention on the elearning
material is
investigated. In this phase, the activities of students using the elearning
material
are analysed and tests and examination results processed to determine whether
there is any correlation between time spent on elearning
material and these
results. The usage of elearning
material is tested by means of an interpretive
questionnaire to the students. The last part of the action research approach deals with the question of whether
the research was conducted successfully. A second iteration of the process proved
the results to be satisfactory.
The elearning
material was positively received by students participating in the
research, while a growing interest in this material was noticed from the last
semester in 2007 to the first semester in 2008.Thesis (M.Sc. (Computer Science))--North-West University, Potchefstroom Campus, 2011.
39
Van, der Westhuizen Christoffel Petrus. "Digital versatile disc as an information and communication technology variant to support geography teaching and learning / Christoffel Petrus Van der Westhuizen." Thesis, North-West University, 2007. http://hdl.handle.net/10394/1467.
Full text
40
King-Smith, Birgitta. "Hans Jacob Christoffel von Grimmelshausen: Die Sinnbezirkedes ausdrucks sehen in Der Abentheurliche Simplicissimus Teutsch und in der Continuatio des abentheurlichen Simplicissimi /." The Ohio State University, 1994. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487853913099947.
Full text
41
Jordaan, Johannes Christoffel. "Die opleiding van geestelik vertraagde kinders binne die Suid-Afrikaanse onderwysstelsel met spesifieke verwysing na die E.S. le Grangesentrum / Johannes Christoffel Jordaan." Thesis, Potchefstroom University for Christian Higher Education, 1988. http://hdl.handle.net/10394/9501.
Full textAbstract:
The mentally retarded child as a member of society should enjoy equality
of rights of existence just like any other individual created by God.
This study endeavours to research the training needed for white mentally
retarded children in the RSA and to what extent these needs are catered
for.
In a literature study an overview is given of relevant concepts and terminology
concerning mental retardation. Concepts with reference to the
Act for the training of mentally retarded children are used.
Possible criteria for identifying mentally retarded children are proposed.
These criteria should be present in a higher or lesser degree to confirm
mental retardation.
The utilization of these criteria are further discussed as aids in the formal
classification of retardedness.
The basic personal and social needs of the mentally retarded child are
perused as well as the need for industrial orientation. Attention is then
also given to the extent to which these needs are addressed in the RSA
and the facilities for "education" and training of these children.
The present criteria for admission and placement of these children in
training centres is also discussed.
An exemplary study of the E.S. le Grange centre for retarded children
was done to illustrate the concepts mentioned. The history and development
of the centre is described. An evaluation was made as to the extent
the needs of the mentally retarded children at the centre are fulfilled in
accordance with the background of Act no. 63 of 1974. It was found that
this centre fully subscribed to the said act.
Individual problem areas were however identified and suggestions put
forward for their rectification.Skripsie (MEd)--PU vir CHO, 1988
42
Grobler, Hendrik Christoffel. "'n Evaluering van die maksimale fisieke werkvermoë en -aktiwiteitsprofiel van uitvoerende amptenare by Hoof van Staf personeel in die SAW / Hendrik Christoffel Grobler." Thesis, Potchefstroom University for Christian Higher Education, 1990. http://hdl.handle.net/10394/1341.
Full text
43
Smit, Jan Jacob Antonie Christoffel. "A conceptual model for the management of the implementation of a continuous assessment plan at a university of technology / Jan Jacob Antonie Christoffel Smit." Thesis, North-West University, 2008. http://hdl.handle.net/10394/1781.
Full textAbstract:
In South Africa today, the challenge is to redress past inequalities and to transform the
higher education system. This transformation of the higher education system is necessary
in order to serve a new social order. The introduction of outcomes-based education and
training requires a new approach to education, including the process of assessment. An
outcomes-based approach to education and training focuses on continuous assessment
through the use of a range of assessment methods.
The Ministry of Education tasked the National Department of Education to embark on a
review of their academic programmes. This review has been in response to register
programmes on the National Qualifications Framework. This review has also been part of
an attempt to improve the quality of qualifications.
In most learning organisations, assessment and learning have always been closely related.
If assessment has not simply been seen as the end point in learning but has been an
important component in the design of the learning process itself, this statement will be
severely tested by the movement towards an outcomes model for education and training.
The primary aim of the study was to develop a conceptual model for the management of
the impleme tation of a continuous assessment plan in a university of technology by
means of aliterature study and an empirical investigation. Currently, information
regarding the conceptualisation of this topic is inadequate and vague. If the nature of the
complexities involved in the management and implementation of CASS at universities of
technology are known, a conceptualised model can be developed for the effective
management of the implementation thereof.
The implementation of an integrated model of assessment requires the creation of an
enabling environment in which the model can be implemented. This study has found that
this is not true for many universities of technology, as:
• programme design still rests on subjects that are not aimed at outcome-based
models;
• administrative systems are not designed to accommodate the recording of
continuous assessments;
• students, lecturers and other stakeholders have not undergone the necessary
training regarding the change in paradigm from content-based to outcomebased
education; and
• policy regarding modularisation and continuous assessment has not yet been
defined and implemented.
The study serves to present a useable model for the management of the implementation
of continuous assessment at universities of technology. The study is based on a balanced
opinion as the experiences of both lecturers and students were investigated by means of
structured questionnaires. The findings were verified by means of a focus group interview
with administrative staff involved with continuous assessment.
The model that was developed is a usable model as it was subjected to a number of
verification tests.Thesis (Ph.D. (Teaching and Learning))--North-West University, Vaal Triangle Campus, 2008.
44
Doghraji, Salma. "Caractérisation de la géométrie locale et globale de textures directionnelles par reconstruction d'hypersurfaces et transformations d'espace : application à l'analyse stratigraphique des images sismiques." Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0814/document.
Full textAbstract:
Les textures directionnelles forment la classe particulière des images texturées représentant des hypersurfaces (lignes dermiques, fibres de matériaux, horizons sismiques, etc.). Pour ce type de textures, la reconstruction d'hypersurfaces permet ainsi d'en décrire la géométrie et la structure. À partir du calcul préalable du champ d'orientation, des reconstructions peuvent être obtenues au moyen de la minimisation d'une équation aux dérivées partielles sous contraintes, linéarisée et résolue itérativement de manière optimale dans le domaine de Fourier.Dans ce travail, les reconstructions d'hypersurfaces sont considérées comme un moyen de description à la fois amont et aval de la géométrie des textures directionnelles. Dans une démarche amont, la reconstruction de faisceaux locaux et denses d'hypersurfaces conduit à un modèle de transformation d'espace permettant de déplier localement la texture ou son champ de gradient et d'améliorer l'estimation du champ d'orientation par rapport au classique tenseur de structure. Dans une démarche aval, des reconstructions d'hypersurfaces effectuées sur des supports polygonaux quelconques, isolés ou imbriqués, permettent d'obtenir des reconstructions plus pertinentes que par les méthodes existantes. Les démarches proposées mettent en œuvre des chaînes de transformations d'espace conformes (transformation de Schwarz-Christoffel, de Möbius, etc.) afin de respecter les contraintes et d'accéder à des schémas de résolution rapideDirectional textures are the particular class of textured images representing hypersurfaces (dermal lines, material fibers, seismic horizons, etc.). For this type of textures, the reconstruction of hypersurfaces describes their geometry and structure. From the preliminary estimation of the orientation field, reconstructions can be obtained by means of the minimization of a partial differential equation under constraints, linearized and iteratively resolved in the Fourier domain.In this work, the reconstructions of hypersurfaces are considered as means of description both upstream and downstream of the geometry of the directional textures. In an upstream approach, the reconstruction of local and dense streams of hypersurfaces leads to a spatial transformation model to locally unfold the texture or its gradient field and to improve the estimation of the orientation field compared with the classic tensor structure. In a downstream approach, reconstructions of hypersurfaces carried out on any polygonal supports, either isolated or imbricated, lead to more accurate reconstructions than existing methods. The proposed approaches implement chains of conformal space transformations (transformation of Schwarz-Christoffel, Möbius, etc.) in order to respect the constraints and to access fast PDE solution schemes
45
Mendez, Milton Javier Cárdenas. "Parametrização de uma hipersuperfície via função suporte no espaço hiperbólico." Universidade Federal de Goiás, 2018. http://repositorio.bc.ufg.br/tede/handle/tede/8225.
Full textAbstract:
Submitted by Franciele Moreira (francielemoreyra@gmail.com) on 2018-03-15T13:27:07Z
No. of bitstreams: 2
Dissertação - Milton Javier Cárdenas Mendez - 2018.pdf: 1063682 bytes, checksum: ab9f203ee1a315ae8756973bcd7c0789 (MD5)
license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-03-16T11:08:51Z (GMT) No. of bitstreams: 2 Dissertação - Milton Javier Cárdenas Mendez - 2018.pdf: 1063682 bytes, checksum: ab9f203ee1a315ae8756973bcd7c0789 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)
Made available in DSpace on 2018-03-16T11:08:51Z (GMT). No. of bitstreams: 2 Dissertação - Milton Javier Cárdenas Mendez - 2018.pdf: 1063682 bytes, checksum: ab9f203ee1a315ae8756973bcd7c0789 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-02-26
Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq
First objective will revise the hyperbolic Gauss map for hypersurfaces Mn C Hn+1 and its relation with tangent horospheres. We will introduce horospherical ovaloids as compact hypersurfaces with regular hyperbolic Gauss map and analyze their properties, analyzes the possible formulations of the Christoffel problem in Hn+1 and that this leads to the notion of hyperbolic curvature radii. Second objective we will prove that the Nirenberg problem on Sn is equivalent to the Christoffel problem in Hn+1. This equivalence is made explicit by means of a representation formula for hypersurfaces in terms of the hyperbolic Gauss map and the horospherical support function.
Nosso primeiro objetivo é revisar a aplicação hiperbólica de Gauss para hipersuperfícies Mn C Hn+1 e sua relação com as horoesferas tangentes, vamos apresentar ovaloides horoesfericos como hipersuperfícies compactas com aplicação regular hiperbólica de Gauss, além disso, queremos dar uma possível formulação do problema de Christoffel em H n+1 com a noção de raios de curvatura hiperbólica. Nosso segundo objetivo é mostrar que o problema de Christoffel em Hn+1 é equivalente ao problema de Nirenberg em Sn, isso é equivalente, dar uma parametrizacão de uma hipersuperfície em termos da aplicão hiperbólica de Gauss e da função suporte horoesferica.
46
Moon, Jihie. "Die verhouding tussen geskiedenis en literatuur in post-apartheid Suid-Afrika, met spesifieke verwysing na Verliesfontein deur Karel Schoeman en Op soek na Generaal Mannetjies Mentz deur Christoffel Coetzee." Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/53390.
Full textAbstract:
Thesis (MA)--Stellenbosch University, 2003.ENGLISH ABSTRACT: This study examines the relationship between history and literature, with specific reference to the Afrikaans novels Verliesfontein (1998) by Karel Schoeman and Op soek na generaal Mannetjies Mentz (1998) by Christoffel Coetzee. Both novels are framed against the background of the Anglo Boer War and both take a postmodern approach to that history, amongst other things. First, Chapter 2 reviews the historical background to the relationship between history and literature through the ages (the classical era, and the eighteenth, nineteenth and twentieth centuries), with a view to indicating how this tradition adheres to the postmodern spirit of contemporary times. Thereafter, Chapter 3 presents a theoretical investigation into the postmodern view of historiography and historical fiction. Special reference is made to Hutcheon's theory of historiographic metafiction as an important theoretical point of departure in the discussion of historical fiction. Political and ideological meaning implicit in historiography is discussed. Chapter 4 explores the current trend in South Africa of rereading and reappraising the past, of questioning traditional historiography in a postapartheid South African context (both in Afrikaans fiction and in historical writing). The revisiting of the Anglo Boer War in contemporary South Africa and in Afrikaans fiction is investigated, and an attempt is made to establish the significance of its reappraisal. Against this background the two texts, Verliesfontein and Op soek na generaal Manntjies Mentz, are discussed in Chapter 5. The two novels amply illustrate the possibility for interaction between history and literature, fact and fiction. How may these texts be read in view of postmodern theory? What lessons for present-day South Africans did Schoeman and Coetzee have in mind with their postmodern questioning of traditional historiography and their unconventional reconstruction of the past? Reappraising conventional accounts of history and exploring personal histories as these texts do, Verliesfontein and Op soek na generaal Mannetjies Mentz are part of the dominant discourse that is taking form in the multicultural society of a postapartheid South Africa today.
AFRIKAANSE OPSOMMING: In hierdie studie is 'n ondersoek onderneem na die verhouding tussen geskiedenis en literatuur, met spesifieke verwysing na Karel Schoeman se roman Verliesfontein (1998) en Christoffel Coetzee se roman Op soek na generaal Mannetjies Mentz (1998). In hierdie twee tekste, wat die Anglo-Boereoorlog as hul raamwerk het, is onder andere 'n postmodernistiese benadering tot die geskiedenis benut. Eerstens word in hoofstuk 2 oorsigtelik gekyk na die historiese agtergrond van die verhouding tussen geskiedenis en literatuur met verloop van die tyd (die klassieke tyd, agtiende eeu, negentiende eeu en twintigste eeu), om aan te dui hoe dié tradisie by die heersende tydsgees van die postmodernisme aansluit. Hierna verskaf hoofstuk 3 'n teoretiese ondersoek na die postmodernistiese manier waarop geskiedskrywing en historiese fiksie gesien word. Die teorie van Hutcheon se historiografiese metafiksie word veral in die bespreking van historiese fiksie betrek as 'n belangrike teoretiese uitgangspunt. Vervolgens kom politieke en ideologiese implikasies in geskiedskrywing onder bespreking. Daarna (hoofstuk 4) word die Suid-Afrikaanse kontemporêre tendens om die verlede te herlees en te herwaardeer uiteengesit, en die ondermyning van die tradisionele geskiedskrywing in die post-apartheid Suid-Afrikaanse konteks (sowel in Afrikaanse fiksie as in geskiedskrywing) word ondersoek. Daar word gefokus op die her-bedenking van die Anglo-Boereoorlog in die hedendaagse Suid-Afrika en in Afrikaanse fiksie, en daar word ook probeer om die betekenis van dié herwaardering te soek. Teen bostaande agtergrond kom die twee tekste, Verliesfontein en Op soek na generaal Manntjies Mentz onder bespreking (hoofstuk 5). Die romans is goeie voorbeelde van die interaksie-moontlikhede tussen geskiedenis en literatuur, feit en fiksie, en daar word ondersoek hoe hierdie twee tekste aan die hand van postmodernistiese teorieë gelees kan word. Uiteindelik word daar besin oor watter lesse Schoeman en Coetzee met die postmodernistiese problematisering van geskiedskrywing en die onkonvensionele rekonstruksie van die verlede aan kontemporêre Suid-Afrikaners wou oordra. Met die herbesinning van die konvensionele weergawe van die geskiedenis en veral deur die verkenning van persoonlike geskiedenisse, vorm Verliesfontein en Op soek na generaal Mannetjies Mentz deel van die heersende diskoers wat vandag in 'n multikulturele samelewing van die post-apartheid Suid-Afrika aan die ontwikkel is.
47
Prinsloo, Christoffel Bernardus. "A study into the fundamental understanding of iron-transformations and the effect of iron as fluxing agent on Highveld fine coal sources during gasification / by Christoffel Bernardus Prinsloo." Thesis, North-West University, 2008. http://hdl.handle.net/10394/2519.
Full text
48
Crow, Timothy D. "A study of the terms Not(h), El(l)end and Jammer in Hans Jakob Christoffel von Grimmelshausen's Der abentheurliche Simplicissimus Teutsch and the Continuatio des abentheurlichen Simplicissimi /." The Ohio State University, 1991. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487694389393323.
Full text
49
Sibilio, Grazia. "Sulla mappa di Riemann per i poligoni." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/18240/.
Full textAbstract:
Il teorema della mappa di Riemann afferma che gli insiemi aperti semplicemente connessi contenuti strettamente nel piano complesso sono biolomorfi al disco unitario. Quando l'aperto semplicemente connesso di cui si parla è un poligono, è possibile trovare una formula esplicita del biolomorfismo. Questo elaborato si propone di studiare alcuni aspetti di tale formula. Viene quindi definita la formula di Schwarz-Christoffel e si mostra che essa si estende con continuità sul bordo del disco unitario.
Successivamente, si utilizza la caratterizzazione delle rette quali curve a curvatura nulla per dimostrare che la formula in questione mappa tratti del bordo del disco in segmenti rettilinei. Infine, ci si avvale della definizione di indice di una curva rispetto ad un punto e del principio dell'argomento come strumenti fondamentali per la dimostrazione del fatto che la restrizione della formula di Schwarz-Christoffel al disco unitario è un biolomorfismo.
50
Canevari, Samuel da Cruz. "A transformação de Darboux-Bianchi para superfícies isotérmicas em R³." Universidade Federal de São Carlos, 2004. https://repositorio.ufscar.br/handle/ufscar/5850.
Full textAbstract:
Made available in DSpace on 2016-06-02T20:28:22Z (GMT). No. of bitstreams: 1
DissSCC.pdf: 580893 bytes, checksum: 668c123be16c687965e925ea0bd5d17b (MD5)
Previous issue date: 2004-04-15Universidade Federal de Minas Gerais
In this work we develop the transformation theory for isothermic surfaces in Euclidean space IR3 due to Darboux and Bianchi. As a consequence, we describe a method for constructing new solutions of the nonlinear system of partial diferential equations associated to an isothermic surface in IR3 starting from a given one.
Neste trabalho apresentamos a teoria de transformações entre superfícies isotérmicas no espaço Euclidiano IR3 devida a Darboux e Bianchi. Descrevemos, como consequência, um método de obter novas soluções do sistema não linear de equações diferenciais parciais associado a uma superfície isotérmica em IR3, a partir de uma dada.