Earnings have numerous properties that can be investigated, including earnings smoothness, abnormal accruals after modelling the accruals process and asymmetric timely loss and gain recognition. In latest decades, as earnings are the main source of firm-specific information for investors, earnings quality has become a significant focus in the financial accounting field. Moreover, high-quality financial reporting helps investors improve decisions and better evaluate firm performance because capital markets depend on the credibility of financial accounting information. The aim of this study investigates the impact of the mandatory adoption of IFRS on earnings quality in term of earnings management and accounting conservatism in consideration of eleven European countries (Germany, France, Italy, The Netherlands, Spain, Sweden, Switzerland, Portugal, Belgium, Norway and the United Kingdom) as a sample study. Then to test whether investors could predict a company's future performance efficiently based on deferred tax expense as one of the accruals components before and after the mandatory adoption of IFRS. Since the mandatory adoption of International Financial Reporting Standards (IFRS) required by the European Union (EU) Parliament, numerous research studies have examined whether earnings management has been reduced due to the mandatory adoption. Chapter two of this study examines whether the board of directors is more effective in constraining earnings management after the mandatory application of IFRS. More specifically, the study explored ways that two board characteristics, board independence and the existence of an audit committee, have impacted earnings management since 2005. The empirical results with eleven European countries (Germany, France, Italy, The Netherlands, Spain, Sweden, Switzerland, Portugal, Belgium, Norway and the United Kingdom) showed evidence of an inverse relationship between the strength of corporate governance and the extent of earnings management. This negative association suggests that firms that apply IFRS with a high level of corporate governance standards are less likely to be involved in earnings management. This study indicates that board independence and the existence of audit committees play important and effective roles in reducing earnings management after the introduction of IFRS. The results also provide evidence that the internationally uniformed accounting regulatory framework significantly contributes to the effectiveness of the two corporate governance mechanisms. Chapter three examines the impact of the mandatory IFRS adoption on the asymmetrically timely gain and loss recognition (accounting conservatism). The findings provide evidence of the importance of the mandatory adoption of IFRS in increasing of accounting conservatism in pooled samples and separate samples. Chapter four investigates whether investors could predict a company's future performance efficiently based on deferred tax expense as one of the accruals components before and after the mandatory adoption of IFRS. Moreover, whether or not the predictions could be generalised to other European countries was examined. The results imply that an accrual anomaly exists in pooled samples before and after mandatory IFRS adoption and the study prove that deferred tax expense as a determinant factor of accounting accruals is overweighed by stocks prices before and after IFRS adoptions.

Les présents travaux de thèse envisagent une nouvelle technique d'optimisation au sens topologique dans des géométries de type canal vertical où se réalisent des transferts de chaleur conducto-convectifs en régime laminaire. Les équations qui décrivent l'écoulement du fluide et le transfert d'énergie sont discrétisées par la méthode des volumes finis. La première partie du mémoire présente une nouvelle technique d'optimisation et sa validation sur des cas d'études de la littérature (single pipe, bend pipe). Cette technique consiste à définir des fonctions d'interpolation de type sigmoïde et permet d'obtenir une amélioration de l'interface fluide-solide au cours du processus d'optimisation. La seconde partie met en évidence les phénomènes physiques dans le canal asymétriquement chauffé, notamment l'influence de la stratification thermique extérieure et du rayonnement de surface sur les quantités aérauliques et thermiques. Enfin, une nouvelle expression de la puissance mécanique pour contrôler les pertes de charge (malgré l'ajout de matière) dans le canal vertical combinée avec une nouvelle expression de la puissance thermique sont étudiées. Le problème ainsi posé est résolu pour un écoulement en convection naturelle. Pour les cas considérés, chacune des fonctions coût est optimisée sans détériorer l'autre. Nous comparons aussi les valeurs des puissances obtenues par notre algorithme avec celles couramment utilisées dans la littérature et montrons que ces nouvelles fonctionnelles sont performantes. / This thesis deals with topology optimization of mass and heat transfer in the framework of the vertical asymetrically-heated channel. The incompressible Navier-Stokes equations coupled to the convection-diffusion equation through the Boussinesq approximation are employed and are solved with the finite volume method. We first propose a new interpolation technique for heat transfer optimization and validate it on referenced cases such as the "single pipe" and the "bend pipe". This new technique consists in the introduction of sigmoid interpolation functions to obain a better definition of the interface between fluid and solid domains, during the optimization process. We study then physical phenomenon in the asymmetrically heated channel , in particular the influence of thermal stratification outside the channel and surface radiation on thermal and dynamic quantities. We thus highlight the size variation of reversed flow at the exit of the channel and the plug-effect linked on external thermal stratification. Finally, we propose a new expression of mechanical power in order to control charges losses (despite addition of material) in the vertical channel combined with the expression of thermal power. In all considered cases, our algorithm succeeds to enhance one of the phenomenon modelled by our new cost functions without deteriorating the other one. We also compare the values of standard cost functions from the litterature over iteration of our optimization algorithm and show that our new cost functions are effective.