Browsing by Author "Waltert, Manuel"

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    Flexible facility requirements for strategic planning of airport passenger terminal infrastructure
    (Taylor & Francis, 2023-11-30) Waltert, Manuel; Jimenez Perez, Edgar; Pagliari, Romano
    Facility requirements determine how and when the capacity of airport passenger terminal facilities is adjusted over time to meet expected demand. Given high levels of uncertainty inherent in long-term airport planning, under and over provision of capacity is a recurrent risk, as conventional strategic planning methods fail to adapt dynamically to changing circumstances. This paper introduces a novel flexible capacity expansion model for airport terminals that considers simultaneously real options ‘on’ and ‘in’ systems. The model is validated for the provision of check-in facilities at Zurich Airport. Results confirm suggestions in the literature that incorporating flexibility creates planning and financial advantages over conventional alternatives. Indeed, for the case of Zurich, the financial value of the flexible alternative is approximately 5% higher than the best conventional phased plan. This also suggests that phasing developments can be carefully devised to produce satisfactory outcomes that enable ex-post application of flexibility ‘on’ systems.
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    Ratio-based design hour determination for airport passenger terminal facilities
    (Elsevier, 2021-08-04) Waltert, Manuel; Wicki, Jan; Jimenez Perez, Edgar; Pagliari, Romano
    To avoid both over-design and under-sizing of airport passenger terminal facilities such as security checkpoints, the infrastructure is designed for a specifically determined design load. As such, the design load is considered for a short period of time, usually an hour of operation, during which peak, though not necessarily maximum, demand occurs. For strategic planning applications, future design loads can be determined by either fictitious flight schedules or ratio-based models which forecast the relationship between design load and annual demand. This study presents two ratio-based methods which allow the direct determination of design hour loads (DHL) for passenger terminal facilities. The unsaturated DHL model considers the relationship between observed passenger flows in the terminal and aggregated annual demand data. The saturated DHL model includes several operational constraints which limit the actual DHL, such as limitations in the runway system or the fleet mix operating at an airport. Both models are applied to two real-world airports, for which the DHL of the security checkpoint facilities is estimated from large datasets covering multiple years. Results are significant at the 5 % level and suggest that the proposed ratio-based methods are appropriate for airport strategic planning applications.
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    Strategic capacity planning framework for airport passenger terminal facilities.
    (Cranfield University, 2022-02) Waltert, Manuel; Pagliari, Romano; Jimenez Perez, Edgar
    Facility requirements describe how the capacity of a facility should be adjusted over time to meet the expected future demand levels. Practitioners use them to determine the strategic development of airport passenger terminal facilities. The generation of facility requirements is extraordinarily complex, since (i) airport strategic planning is subject to high levels of uncertainty due to the extremely long planning horizons considered, and (ii) investments in infrastructure are subject to irreversibility. This study presents a strategic capacity planning framework consisting of two modules, by means of which stochastically optimal facility requirements for airport passenger terminal facilities can be determined. The demand module is applied first. Its purpose is twofold: on the one hand, to create annual aggregated demand scenarios of an airport by means of geometric Brownian motion. On the other hand, to convert these scenarios into facility-specific design hour loads with the help of linear regression models. Subsequently, the capacity expansion problem module is used to determine conventional and flexible facility requirements that maximize the net present value of an airport passenger terminal facility. For this purpose, both conventional and flexible capacity expansion problem models, presented in the literature, are adapted to the needs of airport strategic planning. Subsequently, they are solved with evolutionary optimization algorithms. The framework is applied to a real-world planning example of the existing check- in facilities at Zurich Airport. The aim of the planning example is to compare flexible facility requirements with conventional facility requirements in terms of their economic value, and to investigate how sensitive the proposed models are to variations in several input factors. The results suggest that flexible facility requirements are generally more valuable than conventional facility requirements. Moreover, the models applied in this study respond to changes in input factors in a similar way to comparable models documented in the literature.