published_or_final_version / Politics and Public Administration / Doctoral / Doctor of Philosophy

published_or_final_version / Public Administration / Master / Master of Business Administration

published_or_final_version / abstract / Business / Master / Master of Philosophy

published_or_final_version / abstract / Statistics and Actuarial Science / Master / Master of Philosophy

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No description available.

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D.Com. / Valuation is an intricate and complex problem. There are many approaches and models pertaining to this problem. The result of all these approaches is that investors are still confused because they are not fully, acquinted with the problems and strengths of the different approaches and models. It is therefore important to try to soIve this problem. The object of the study is to examine all the different approaches, especially the Capital Asset Pricing Model which has undergone extensive development. The literature is thoroughly discussed and various theoretical models which can be used in the valuation process are evaluated critically. The models which are discussed range from the traditional models to the more modern models of valuation. By using the information of 60 shares, the different approaches are empirically tested and practical problems are discussed.

Thesis (M.M. (Finance & Investment))--University of the Witwatersrand, Faculty of Commerce, Law and Management, Graduate School of Business Administration, 2013. / This thesis aims to investigate the influence of earnings news on stock liquidity and the relationship between information asymmetry cost component and Post Earnings Announcement Drift in different equity markets. The scope of this research includes 426 firms from three countries in capital trading, the United States of America, South Africa and France. The first part of empirical work, shows that price reaction and liquidity effect are profound during short term event window length and reduce over time when the news ceases, The second part, a multivariate regression analysis which uses Generalised Method of Movement to capture both the problems of a likely presence of endogeneity between the explanatory variables and cross-stock heterogeneity, shows that the impact of earnings announcement on stock liquidity can split in two directions. The immediate effect is the shock after the news, causing stock liquidity to decrease immediately by lifting the illiquidity function upward. After the event, from the new increased position of illiquidity function, stock liquidity improves over time due to the trading volume increases and shifts the slope of illiquidity function downward. The overall effects at a point of time will be the total impact of the two side effects. And as shown in the results, the overall impact on the US and SA markets are that stock liquidity decreases while that of Euronext Paris, the stock liquidity increases. There are two types of Accounting law systems of which the common law system is used in the US and SA equity markets and the code law system used in France, the difference between the two law systems is that the information asymmetry component dominates the bid-ask spread in common law countries as in the US and SA markets while the cost of trading dominates the bid-ask spreads in code law countries such as France equity market. Finally, it is shown that there are several determinants of the PEAD, of which stock liquidity is one. Earnings news changes the stock liquidity, and therefore stock liquidity plays a role in the market response. When earnings news is released, it initially creates a gap between the informed traders and the uninformed traders, increasing the bid ask spread. Over time, this information gap decreases, however in the meantime more information on the market increases trading volume and reduces trading cost, leading to another part of the bid ask spread decreasing or stock liquidity improving. After decomposing bid ask spread into information asymmetry cost and cost of trading components, the final part of empirical iv analysis shows that information asymmetry cost component provides a partial explanation for PEAD in the Johannesburg stock exchange and Euronext Paris.

Cette thèse s’inscrit dans le cadre d’une problématique globale de recherche qui porte sur la modélisation et l’optimisation des chaînes logistiques. Il s’agit de développer, pour deux maillons successifs d’une chaîne logistique, des modèles pour résoudre le problème du lot économique commun en intégrant les aspects liés à la production, à la qualités des produits et à la maintenance.Le choix d’une politique de production continue, jusque là adoptée dans la littérature, est à l’origine d’accumulation de stock chez le fournisseur ou chez le client selon que les livraisons sont respectivement retardées ou immédiatement transférées.Dans notre travail nous proposons une nouvelle alternative de production basée sur le principe «ne produire que le besoin du client à livrer immédiatement». Globalement, l’idée se résume à produire la commande par lots séparés de taille optimale immédiatement transférés au client, cherchant à réduire le stock moyen dans le système. Dans un mauvais scénario, correspondant à une éventuelle amplification du nombre de setup, le gain sur le stockage couvrirait la perte au niveau du setup lorsque le coût unitaire de celui-ci est relativement réduit.Cherchant un meilleur compromis entre les coûts de stockage, de setup et de livraison, cette solution est généralisée par la suite au cas où la taille du lot produit est différente des tailles de la commande et des livraisons.L’étude est étendue au cas d’une production imparfaite caractérisée par un taux moyen fixe de non conformités. Les stratégies continue et lot-par-lot sont reformulées en intégrant des actions de maintenance dont le but est de réduire le coût de non-qualité et d’optimiser le coût total / In this work we deal with the single vendor single buyer integrated production inventory problem. In the beginning, two production strategies are compared. The first one, proposed by Ben-Daya and Hariga (2004), suggests that the buyer orders batches of size nQ every time his on hand inventory reaches the reorder point r after the reception of the ultimate lot of the last order. The vendor from his side produces continuously nQ and makes equal shipments of size Q. The second policy, which we develop, propose that to satisfy the same ordered quantity, the vendor produces separately smaller batches of size Q (lot-for-lot), n times. The total expected cost is adopted as the decision variable for the choice of the best strategy.Afterwards, the lot-for-lot strategy is generalised to the cases where the sizes of the produced lot and the shipment are different from the ordered quantity. Henceforth, the vendor manufactures separately smaller batches of size iQ and makes equal shipments of size jQ (1≤ j ≤ i ≤ n) limited or not to the transportation capacity. The optimal solution corresponds to the best combination (n, i, j, Q, r) yielding the minimal total average cost per time unit incurred by the vendor and the buyer.In the last contribution, we consider the case of an imperfect process where the production unit is assumed to randomly shift from an in-control to an out-of-control state characterized by a fixed production rate of non-conforming items. To resolve the problem, we propose and compare two different strategies integrating production, inventory and maintenance policies. The maintenance actions are performed to prevent or to reduce the losses related to imperfect items