Dans cette thèse sur articles nous nous intéressons aux contraintes observationnelles sur les modèles d'inflation cosmologique et nous étudions certains aspects fondamentaux liés à la nature quantique de la physique inflationnaire. Nous commençons par analyser de façon systématique les modèles à un champ scalaire et avec terme cinétique standard. Dans l'approximation du roulement lent, et en intégrant les contraintes venant du réchauffement, nous dérivons les prédictions associées à environ 75 potentiels. Nous utilisons ensuite les techniques d'inférence Bayésienne pour classer près de 200 modèles inflationnaires et contraindre leurs paramètres. Cela permet d'identifier les modèles favorisés par les observations et de quantifier les niveaux de tensions entre les différents jeux de données. L'intérêt d'une telle approche est renforcé par l'étude de méthodes indépendantes du modèle telle que le ``flot de Hubble'', qui se révèle biaisé. Nous calculons également le spectre de puissance au deuxième ordre pour les modèles d'inflation-k.Ensuite, nous décrivons certains aspects quantiques de la physique inflationnaire. Le formalisme de l'inflation stochastique est notamment utilisé dans le cadre du modèle à deux champs d'inflation hybride. Nous discutons les corrections quantiques sur les prédictions de ce modèle, et à l'aide d'un formalisme récursif, nous nous intéressons à la façon dont elles modifient l'amplitude des perturbations. Finalement, la transition quantique-classique et le problème de la mesure quantique sont étudiés dans un contexte cosmologique. Un modèle de réduction dynamique du paquet d'onde est appliqué à la description des perturbations inflationnaires. / This thesis by publication is devoted to the study of the observational constraints on cosmological inflationary models, and to the investigation of fundamental aspects related to the quantum nature of the inflationary physics.We first present a systematic analysis of all single-scalar-field inflationary models with canonical kinetic terms. Reheating consistent slow-roll predictions are derived for ~ 75 potentials, and Bayesian inference and model comparison techniques are developed to arrange a landscape of ~ 200 inflationary models and associated priors. In this way, we discuss what are the best models of inflation, and we properly quantify tension between data sets. Related to this massive sampling, we highlight the shortcomings of model independent approaches such as the one of ``horizon-flow''. We also pave the way for extending our computational pipeline to k-inflation models by calculating the power spectrum at next-to-next-to leading order for this class of models.In a second part, we describe some aspects related to the quantum nature of the inflationary setup. In particular, we make use of the stochastic inflation formalism, which incorporates the quantum corrections to the inflationary dynamics, in the two-field model of hybrid inflation. We discuss how the quantum diffusion can affect the observable predictions in such models, and we design a recursive strategy that incorporates its effects on the perturbations amplitude. Finally, we investigate the quantum-to-classical transition and the quantum measurement problem in a cosmological context. We apply a dynamical wavefunction collapse model to the description of inflationary perturbations.

The diploma thesis focuses on inflation targeting in central Europe. It describes experience of three central European countries (Czech republic, Poland, Hungary) with inflation targeting. First part of thesis deals with theoretical aspects of inflation targeting. Next part brings closer look at application of inflation targeting in above - mentioned countries. Last part of thesis analyzes efficiency of inflation targeting.

Is inflation targeting an appropriate framework for monetary policy? Experience from the inflation-targeting countries countries are optimistic about inflation targeting as a monetary-policy framework. South Africa is also following this trend. The international literature review of the topic offers lessons to be learnt from the common experience of the countries considered. It shows that inflation targeting is not a universal remedy to modern economic ills -- there is an emerging danger of assigning monetary policy a larger role than that which it can perform; a danger of expecting monetary policy to accomplish tasks that it cannot achieve; and a danger of preventing monetary policy from making the contribution that it is capable of doing. Therefore, inflation targeting cannot address all the macroeconomic problems that face many countries, except for inflation. Nonetheless, it plays a crucial role in improving macroeconomic performance. / Economics / M.A. (Economics)

Technical report (MBA) -- University of Stellenbosch, 1987. / University of Stellenbosch Business School / ENGLISH ABSTRACT: Two methods of inflation adjustments are explained and evaluated to determine which method gives better results for a company with a given capital structure. The objective was to lay down a method to predict, without detai l and difficult ca l culus , the preferred method to use for a company with a known financial structure . The resul ts of the two methods and for differen t companies notated on the Johannesburg Stock Exchange , are shown in the Appendices. / AFRIKAASE OPSOMMING: Twee metodes vir inflasie regstelling is verduidelik en geevalueer ten einde vas te stel watter metode beter resultate lewer vir 'n maatskappy met 'n gegewe kapitaalstruktuur. Die doelwit was om 'n metode daar te stel om te voorspel. sander detail berekeninge. watter metode verkieslik is vir 'n maatskappy met 'n bekende finansiele struktuur. Die resultate van die twee metodes en vir verskillende maatskappye genoteer op die Johannesburgse Effekte Beurs is getoon in bylaagvorm.

This thesis,firstly, studies the impact of financial liberalization and political instability on economic growth and quantitatively examines the relative importance of the identified underling reasons of Argentine riddle by using an innovative econometric methodology and unique data set: it presents power ARCH estimates for Argentina from 1896 to 2000. The main results show that the long-run effect of financial liberalization on economic growth is positive while the short-run effect is negative, albeit substantially smaller. The political instability effects are substantially larger in the short-run than in the long-run. We also investigate potential mechanisms for the effects of financial liberalization and political instability on economic growth: direct impact or happening through the variation of growth volatility. Our results also suggest that financial development, trade openness and political instability are the main factors to explain the Argentine decline. Furthermore, real business cycle variability - growth relationship and the link between inflation and its uncertainty are investigated by using monthly data of four Asian countries/regions (Japan, South Korea, Singapore and Taiwan) and parametric power ARCH methodology to proxy uncertainty. We fnd that more uncertainty about output leads to a higher rate of growth in three of the four countries/regions and the form of the uncertainty matters. Output growth reduces its uncertainty in all countries/regions via inflation uncertainty except Singapore. For all countries/regions, inflation significantly raises inflation uncertainty as predicted by Friedman. On the other hand, increased uncertainty affects inflation positively in Japan and Singapore, which support the Cukierman-Meltzer hypothesis. We find a negative sign for Taiwan which is in accordance with the Holland hypothesis when error term was normally distributed, however, this result is not statistically significant when the student-t distribution is applied. Interestingly, South Korea’s data reveals a positive sign initially, however, it turns around when a structural dummy is incorporated. This dramatic outcome in favour of the Holland hypothesis, and chimes in with Dueker and Kim (1999), who claim that the inflation was strictly controlled by the South Korean monetary authority. In addition, this thesis investigates two-way causal relationships between spread, volatility and volume in the FTSE100 stock index over the period from 1992 to 2004 by using bivariate AR-FI-GARCH model and multiple measurements of risk and spread. The measurements of the spread include relative bid-ask spread, effective bid-ask spread, the inventory cost component of the bid-ask spread and the information cost component of the bid-ask spread. Risk is proxied by two measurements of price volatility: the close-to-close volatility and the range-based volatility. We also take the impact of electronic trading into account. Our results suggest that the spread and volume are positively impacted by volatility simultaneously. In addition, both volatility and volume are negatively affected by the spread. Furthermore, we find that the inventory cost component of the spread has a negative effect on volatility, in contrast, the information component of the spread positively impacts volatility. These results support the argument that speculation generates volatility in the market and higher transaction costs bene t stability of the market.

published_or_final_version / Economics and Finance / Master / Master of Economics

No description available.

No description available.

No description available.

No description available.