The Quasi Random Walk

Le but de cet article est de profiter de récentes découvertes en économétrie (processus ARCH) pour reformuler les tests classiques d'efficience des marchés financiers. Il est tenté, également, d'améliorer la qualité de la prévision des indices boursiers. Les tests classiques d'efficience sont réalisés à partir du modèle de la marche aléatoire. Le changement intervient, ici, en posant l'innovation du processus de marche aléatoire non plus comme un bruit blanc mais comme un processus ARCH dont les caractéristiques sont telles qu'elles respectent les conditions posées par Granger et Morgenstern (1970) pour tester l'efficience des marchés. Ce modèle, la Quasi Marche Aléatoire, permet une approche moins restrictive de la notion d'efficience. L'autre avantage de la Quasi Marche Aléatoire est qu'il va permettre d'affiner la prévision, grâce aux intervalles de confiance de prévision qui ne sont plus constants. Une étude empirique basée sur cinq indices boursiers mondiaux (Allemagne, États-Unis, France, Grande-Bretagne et Japon) va mettre à jour une plus grande tolérance de la Quasi Marche Aléatoire dans les tests d'efficience des marchés financiers et une meilleure appréhension de la prévision.The intention of this article is to take advantage of recent discoveries in econometrics (ARCH processes) to reformulate classical tests about the efficiency of financial market. It is also intended to improve the quality of stock index forecasts. Classical tests about the efficiency are realized from random walk. The change occurs here, considering the innovation of the random walk not like a white noise but like an ARCH process whose characteristics are such that they respect conditions given by Granger and Morgenstern (1970) to test the market's efficiency. This model, the Quasi Random Walk, allows a less restrictive approach to the notion of efficiency. The other advantage of the Quasi Random Walk is that it will help to refine the forecast, owing to confidence interval of forecast which aren't constant anymore. An empirical study based on five financial indexes (Germany, the United States, France, Great-Britain and Japan) shows a bigger tolerance of the Quasi Random Walk in tests of financial market's efficiency and a better approach to forecast.ou

Implications of population ageing for the development of tourism products and destinations

Population ageing has been identified as a critical element of demographic change which is a key driver for future consumer demand. Driven by the size of the baby boomer generation, population ageing is likely to affect the future choice of tourism activities and destinations. As the baby boomers retire, their demand patterns and preferences will grow in significance and will strongly influence the future structure of tourism product development. Two case studies are used to demonstrate possible impacts of population ageing on tourism demand and the potential implications for product and destination development. The paper discusses the need to consider demand preferences that are influenced by generational membership and identifies the conditions that may lead to the emergence of a product gap if the changing patterns of demand are ignored