383 research outputs found

    Designing Efficient Taxi Pickup Operations at Airports

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    This paper provides a practical procedure for designing efficient taxi pickup operations at airports. How to do this effectively is an open question. Solutions are not available, and practices vary. They reflect different approaches to and lack of research on the subject. The solutions are often unsatisfactory. At many airports, passengers routinely suffer long waits outdoors, exposed to the elements, after a tiring journey. Such disagreeable experiences are avoidable. Designing efficient taxi pickup operations at airports is problematic. The peculiarities of the process preclude easy solutions. First, the process involves queuing, so system performance is a nonlinear function of the loads. Second, it features unstable transient situations, since travelers typically arrive in bulk over short periods. Third, traffic is significantly differentiated and consists of a wide variety of groups implying different service characteristics. Standard results from queuing theory thus do not have a useful application to this problem. The design process uses simulation that is based on detailed observation of local practices. It involves four steps: (a) detailed local measurements of the arrival of both travelers and taxis, and the service rates provided by taxis in different queuing positions; (b) creation and validation of a simulation model sufficiently detailed to account for these realities; (c) exploration of design alternatives to estimate the characteristics of the service they would provide; and (d) selection of a preferred design that properly balances efforts to minimize average and extreme wait times. The paper demonstrates the procedure through application to Lisbon International Airport, Portugal.SIMUL8 Corporatio

    HIV/AIDS, demography and development: individual choices versus public policies in SSA

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    Despite the increasing rate of diffusion of effective therapies, the battle against HIV/AIDS in Sub-Saharan Africa (SSA) is far from being over. Three main challenges are that the epidemics might paralyse or reverse the fertility transition, the expansion of the resources needed to finance the fight against HIV, and the emerging resistance to anti-retroviral treatments. This research proposes a UGT-like model showing the complexity of the interplay amongst the (macro)economy, the epidemics, their endogenous feedback on mortality and fertility and the central role of policy actions aimed to fight HIV. The disease-induced increase in adult mortality can hamper economic development by its upward pressure on the precautionary demand for children and downward pressure on education. This can dramatically reduce physical and human capital accumulation

    An OLG model of growth with longevity : when grandparents take care of grandchildren

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    By assuming that grandparents take care of grandchildren, this paper aims at studying the effects of longevity on long-term economic growth in a model with overlapping generations and endogenous fertility. We show that an increase in longevity may: (i) reduce the long-term economic growth; (ii) increase the supply of labour, and (iii) cause fertility either to increase of decrease depending on the size of time spent by grandparents to rise grandchildren. These findings also hold in an endogenous growth setting a` la Romer (J Polit Econ 94:1002–1037, 1986).info:eu-repo/semantics/publishedVersio
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