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Increasing availability of the financial data has opened new opportunities for quantitative modeling. It has also exposed limitations of the existing frameworks, such as low accuracy of the simplified analytical models and insufficient interpretability and stability of the adaptive data-driven algorithms. I make the case that boosting (a novel, ensemble learning technique) can serve as a simple and robust framework for combining the best features of the analytical and data-driven models. Boosting-based frameworks for typical financial and econometric applications are outlined. The implementation of a standard boosting procedure is illustrated in the context of the problem of symbolic volatility forecasting for IBM stock time series. It is shown that the boosted collection of the generalized autoregressive conditional heteroskedastic (GARCH)-type models is systematically more accurate than both the best single model in the collection and the widely used GARCH(1,1) model.

Tourism, as a leading source of income for many countries, is one of the world's fastest-growing industries. Tourism demand is strongly influenced by the economic situation of the consumer, as well as by the political, environmental, security and health conditions provided by the host country. As tourism is not one of the first steps in Maslow's hierarchy of needs, it is not part of the mandatory spending group. Holiday plans are among the first to be altered or cancelled if there is a threat to the tourist's ‘biological and physiological needs’ or ‘security needs’. Thus, the tourism sector is highly susceptible to crises. Turkey tourism movement has faced several major national and global shocks of different origins recently. This study aims to examine the impact of crucial crises and of the current COVID-19 pandemic on the tourism industry in terms of their characteristics, social conflicts, political situation and responses. To achieve this objective, the development of the tourism sector in Turkey has been analyzed taking into account the conditions of the world economies. Comparisons were made between overall figures for incoming tourists, tourism revenues and hotel occupancy rates in Turkey for the time periods before, during and after these crises, considering certain other effects. The figures are related to significant incidents, economic, political, health, social or environmental crises that have occurred at the national or global level.