This study examines the effects of 2007/8 financial crisis on capital structure determinants of Johannesburg Stock Exchange (JSE) listed companies in South Africa. Data extracted from INET BFA Expert database was analyzed using regression models on the correlation between the leverage and company size, growth, profitability, tangibility, liquidity, non-debt tax shield along with Ordinary Least Squares based on the sample of JSE listed companies for the period of 2004 to 2013. The study examined two industries namely, Real estate and Retail industry. The results show that size, tangibility, profitability and liquidity have significant impact on the capital structure before, during and after financial crisis. Growth results were inconsistent over the period under review, and non-debt tax shield was found to be statistically insignificant. The study also shows that the 2007/8 had statistical significance on the capital structure of the listed companies in South Africa.

Circular words, also known as necklaces, are combinatorial objects closely related to linear words. A brief history of circular words is given, from their early conception to present results. We introduce the concept of a level word, that being a word containing a equal or roughly equal amount of each letter. We characterize exactly the lengths for which level square free circular words on three letters exist. This is accomplished through a modification of Shur’s construction of square-free circular words. A word on two letters is called a Frankel-Simpson word if the only squares it contains are 00, 11, and 0101. Using the result mentioned above and several computer searches, we characterize exactly the lengths for which circular Frankel-Simpson words exist, and give an example or construction for each. / Graduate

Dans les années 90 Garsia et Haiman ont introduit le $mathfrak S_n$-module des emph{harmoniques diagonales}, c'est à dire les co-invariants de l'action diagonale du groupe symétrique $mathfrak S_n$ sur les polynômes à deux ensembles de $n$ variables. Ils ont proposé la conjecture selon laquelle le caractère de Frobenius bi-gradué de leur module est $abla e_n$, où $abla$ est un opérateur sur l'anneau des fonction symétriques. En 2002, Haiman prouva cette conjecture. Quelques années plus tard, Haglund, Haiman, Loehr, Remmel et Ulyanov proposèrent une formule combinatoire pour la fonction symétrique $abla e_n$, qu'ils appelèrent la emph{conjecture shuffle}. Les objets combinatoires qui y figurent sont les chemins de Dyck étiquetés. Un raffinement emph{compositionnel} de cette formule fut ensuite proposé par Haglund, Morse et Zabrocki. C'était ce raffinement que Carlsson et Mellit réussirent enfin à montrer en 2018, établissant ainsi le emph{théorème shuffle}. La emph{conjecture Delta} est une paire de formules combinatoires pour la fonction symétrique $Delta'_{e_{n-k-1}}e_n$ en termes des chemins de Dyck étiquetés et décorés, qui généralise le théorème shuffle. Elle fut proposée par Hagund, Remmel et Wilson en 2015 est reste aujourd'hui un problème ouvert. Dans la même publication les auteurs proposèrent une formule pour $Delta_{h_m}Delta'_{e_{n-k-1}}e_n$ en termes de chemins de Dyck partiellement étiquetés et décorés, appelé emph{conjecture Delta généralisée}. Nous proposons un raffinement compositionnel de la conjecture Delta en utilisant des nouveaux opérateurs de fonctions symétriques: les opérateurs Theta. Nous généralisons les arguments combinatoires que Carlsson et Mellit utilisèrent pour la preuve du théorème shuffle au contexte de la conjecture Delta. Nous prouvons également la formule pour $Delta_{h_m} abla e_n$ en termes de chemins de Dyck partiellement étiqueté, c'est à dire le cas $k=0$ de la conjecture Delta généralisée. En 2006, Can et Loehr proposèrent la emph{conjecture carré}, exprimant la fonction symétrique $(-1)^{n-1}abla p_n$ en termes de chemins carrés étiquetés. Sergel montra que le théorème shuffle implique la conjecture carré. Nous généralisons le résultat de Sergel en montrant que une des formules de la conjecture Delta généralisée implique une formule combinatoire de la fonction $(-1)^{n-k}Delta_{h_m}Theta_kp_{n-k}$ e / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

Least-squares migration has been shown to be able to produce high quality migration images, but its computational cost is considered to be too high for practical imaging. In this dissertation, a multisource least-squares reverse time migration algorithm (LSRTM) is proposed to increase by up to 10 times the computational efficiency by utilizing the blended sources processing technique. There are three main chapters in this dissertation. In Chapter 2, the multisource LSRTM algorithm is implemented with random time-shift and random source polarity encoding functions. Numerical tests on the 2D HESS VTI data show that the multisource LSRTM algorithm suppresses migration artifacts, balances the amplitudes, improves image resolution, and reduces crosstalk noise associated with the blended shot gathers. For this example, multisource LSRTM is about three times faster than the conventional RTM method. For the 3D example of the SEG/EAGE salt model, with comparable computational cost, multisource LSRTM produces images with more accurate amplitudes, better spatial resolution, and fewer migration artifacts compared to conventional RTM. The empirical results suggest that the multisource LSRTM can produce more accurate reflectivity images than conventional RTM does with similar or less computational cost. The caveat is that LSRTM image is sensitive to large errors in the migration velocity model. In Chapter 3, the multisource LSRTM algorithm is implemented with frequency selection encoding strategy and applied to marine streamer data, for which traditional random encoding functions are not applicable. The frequency-selection encoding functions are delta functions in the frequency domain, so that all the encoded shots have unique non-overlapping frequency content. Therefore, the receivers can distinguish the wavefield from each shot according to the frequencies. With the frequency-selection encoding method, the computational efficiency of LSRTM is increased so that its cost is comparable to conventional RTM in the examples of the Marmousi2 model and a field data set from the Gulf of Mexico. With more iterations, the LSRTM image quality is further improved. The numerical results suggest that LSRTM with frequency-selection is an efficient method to produce better reflectivity images than conventional RTM. In Chapter 4, I present an interferometric method for extracting the diffraction signals that emanate from diffractors, also denoted as seismic guide stars. The signal-to-noise ratio of these interferometric diffractions is enhanced by √N, where N is the number of source points coincident with the receiver points. Thus, diffractions from subsalt guide stars can then be rendered visible and so can be used for velocity analysis, migration, and focusing of subsalt reflections. Both synthetic and field data records are used to demonstrate the benefits and limitations of this method.

In this dissertation, new theoretical results are obtained for bounding convergence and mean-square error in conditional coding. Further new statistical methods for the practical application of conditional coding are developed. Criteria for the uniform convergence are first examined. Conditional coding Markov chains are aperiodic, π-irreducible, and Harris recurrent. By applying the general theories of uniform ergodicity of Markov chains on genera l state space, one can conclude that conditional coding Markov cha ins are uniformly ergodic and further, theoretical convergence rates based on Doeblin's condition can be found. Conditional coding Markov chains can be also viewed as having finite state space. This allows use of techniques to get bounds on the second largest eigenvalue which lead to bounds on convergence rate and the mean-square error of sample averages. The results are applied in two examples showing that these bounds are useful in practice. Next some algorithms for perfect sampling in conditional coding are studied. An application of exact sampling to the independence sampler is shown to be equivalent to standard rejection sampling. In case of single-site updating, traditional perfect sampling is not directly applicable when the state space has large cardinality and is not stochastically ordered, so a new procedure is developed that gives perfect samples at a predetermined confidence interval. In last chapter procedures and possibilities of applying conditional coding to mixture models are explored. Conditional coding can be used for analysis of a finite mixture model. This methodology is general and easy to use.

In many problems involving the solution of a system of nonlinear equations, it is necessary to keep an approximation to the Jacobian matrix which is updated at each iteration. Computational experience indicates that the best updates are those that minimize some reasonable measure of the change to the current Jacobian approximation subject to the new approximation obeying a secant condition and perhaps some other approximation properties such as symmetry. All of the updates obtained thus far deal with updating an approximation to an nxn Jacobian matrix. In this thesis we consider extending most of the popular updates to the non-square case. Two applications are immediate: between-step updating of the approximate Jacobian of f(X,t) in a non-autonomous ODE system, and solving nonlinear systems of equations which depend on a parameter, such as occur in continuation methods. Both of these cases require extending the present updates to include the nx(n+l) Jacobian matrix, which is the issue we address here. Our approach is to stay with the least change secant formulation. Computational results for these new updates are also presented to illustrate their convergence behavior.

Textile waste, both pre and post consumer, is a problem that needs a solution, and fast. This work aims to find a simple solution to that problem, to exemplify how a small change in thinking and structures can make a big difference. The proposal is a design system of square construction, with roots in historical fabric conservancy practices and by use of salvage craft techniques. By constructing garments out of squares, waste is eliminated by simple means and existing materials of different qualities can be cut in the same way, thereby rationalized, then assembled into larger materials and so an up cycling process is achieved. The result of this work is a versatile design system which may lead to many different outcomes in the hands of different designers without compromising on desired fit and without the waste generated from cutting conventionally. In the present fashion field solutions such as this system are necessary to encourage the apprehensive designer to take steps towards sustainable practices.

The building of the theater replaces the building of the current small scene on Mariánské náměstí

Till Nynäshamns största utmaningar räknas deras utbildningsnivå, som är en av Sveriges sämsta. Få studerar vidare och kommunens arbetskraft tycks bli mer missanpassad efter kommunens behov. Därtill verkar även deras företagsklimat utgöra ett bekymmer. Det beskrivs som begränsande, vilket är extra alarmerande sett till att majoriteten av kommunens skatteintäckter härstammar från deras småföretagare. Bland dessa upplever två tredjedelar att företagsklimatet är dåligt och 25% överväger därför att flytta sin verksamhet från kommunen.  En rapport har tagits fram för att utvärdera hur Nynäshamn skulle kunna göra för att hantera problemet. Svaret är ett näringslivs- och innovationscenter, som innehåller co-working, Campus Nynäshamn och småskalig kulturverksamhet. Denna hybrid utgör mitt projekt.  Parallellt har Nynäshamn ett annat problem. Staden, döpt efter sin hamn, har en bred och vacker vattenlinje, som är helt dominerad av bilar, stora fartyg och parkeringar. Precis bakom axeln från stad till hamn vill jag därför placera en barriär mot bilarna och skapa ett torg bland den småskaliga fiskhandeln och restaurangverksamheterna och således ta vattnet till folket - staden till vattnet. Hus för folket blir alltså också ett torg för folket, precis vid pendelstationen. / Among Nynäshamn's biggest challenges, their educational level stands out as one of the worst in Sweden. Few people pursue further education, and the municipality's workforce seems to become increasingly mismatched with the municipality's needs. Additionally, their business climate also poses a concern. It is described as restrictive, which is particularly alarming considering that the majority of the municipality's tax revenues come from small business owners. Among these, two-thirds perceive the business climate as poor, and 25% are therefore considering relocating their businesses from the municipality. A report has been developed to evaluate how Nynäshamn could address the problem. The answer is a business and innovation center, which includes co-working spaces, Campus Nynäshamn, and small-scale cultural activities. This hybrid represents my project. Simultaneously, Nynäshamn has another problem. The city, named after its port, has a wide and beautiful waterfront that is completely dominated by cars, large ships, and parking lots. Right behind the axis from the city to the port, I want to create a barrier against cars and establish a square among the small-scale fish trade and restaurant activities, thus bringing the water closer to the people - the city to the water. Therefore, the buildings for the people will also become a square for the people, right next to the commuter station.

>Magister Scientiae - MSc / We are fast moving into an era where data will be the primary driving factor for discovering new unknown astronomical objects and also improving our understanding of the current rare astronomical objects. Wide field survey telescopes such as the Square Kilometer Array (SKA) and Vera C. Rubin observatory will be producing enormous amounts of data over short timescales. The Rubin observatory is expected to record ∼ 15 terabytes of data every night during its ten-year Legacy Survey of Space and Time (LSST), while the SKA will collect ∼100 petabytes of data per day. Fast, automated, and datadriven techniques, such as machine learning, are required to search for anomalies in these enormous datasets, as traditional techniques such as manual inspection will take months to fully exploit such datasets.