2,658 research outputs found
Hub operations delay recovery based on cost optimisation - Dynamic cost indexing and waiting for passengers strategies
In this paper, two strategies for airlines’ operations at a hub are combined and analysed: dynamic cost indexing, to recover delay, and waiting for connecting passengers at the hub. Agent Based Modelling techniques have been used to model the airlines’ operations considering detailed passenger’s itineraries, an extended arrival manager operation with slot negotiation, and delay and uncertainty at different phases of the flights. Results show that, when optimising the total cost, there is a trade-off between connecting and non-connecting passengers with respect to the gate to gate trip time. Waiting for passengers arises as an interesting technique when minimising airline operating costs
What cost reslience?
Air traffic management research lacks a framework for modelling the cost of resilience during disturbance. There is no universally accepted metric for cost resilience. The design of such a framework is presented and the modelling to date is reported. The framework allows performance assessment as a function of differential stakeholder uptake of strategic mechanisms designed to mitigate disturbance. Advanced metrics, cost- and non-cost-based, disaggregated by stakeholder subtypes, will be deployed. A new cost resilience metric is proposed
Comportamiento biológico intraarticular de distintos aloinjertos tendinosos: estudio experimental
Se ha efectuado un estudio experimental comparativo, con valoración macro y microscópica,
de la supervivencia, dentro de la articulación de la rodilla del conejo, de tendones flexores
sobre extensores y dentro de estos, entre tendones conservados en fresco, congelados,
liofilizados y fijados en solución de glutaraldehido al 0,2%. Los tendones se mantuvieron libres en
la articulación receptora durante periodos distintos de tiempo. Entre los resultados destaca la pérdida
de volumen, en el tiempo, de la masa tendinosa (18% de despariciones totales, con un 28%
de pérdida final global). Los tendones fijados en glutaraldehido fueron los que presentaron menor
pérdida de volumen. Los tendones implantados en fresco y los congelados presentaron una mayor
tasa de infección. La mejor respuesta de supervivencia se detectó en los tendones conservados en
glutaraldehido y los congelados. Asà mismo, tenÃan más posibilidades de sobrevivir los flexores que
los extensores. Desde el punto de vista histológico, los tendones conservados en fresco desencadenaron
una mayor respuesta inflamatoria, con gran alteración estructural. Desde el punto de vista
microscópico no se han hallado diferencias significativas entre flexores y extensores.Different groups of flexor and extensor tendons have been compared in their
abitihty survive within the rabbit knee joint. Tendons were grouped and compared according
four different storage procedures like freezing, lyophylization and fixation in 0,2% glutaraldehid.
Some of them were used in fresh. All tendons have been kept inside the joint as free
graft. All specimens lost weight along the study (18% of total loosing of specimen, and 28% of
global loosing). Tendons fixed in disclosed less loosing of volume. Allograft infection was
related to the method o glutaraildehid of storage, relationship being statistically significant (fresh tendons
and frozen tendons were infected more easily). The best survival was found in both frozen
and glutaraldehid fixed tendons. Flexor tendons show more chances of survival than extensors
tendons. Histologically, fresh tendons disclosed the greatest inflammatory reaction. Opposite to
the macroscopic findings, there were no significant differences between flexors and extensors
tendons in the microscopical study
CASSIOPEIA II D3.2 - Final technical report
The FlightPath 2050 presents Europe’s Vision for Aviation for the future. In what refers to air traffic management, this vision includes concrete goals for the punctuality of flights and capacity of the air traffic management system. Additionally, the document adds a concrete goal in what refers to passenger mobility, stating that 90% of the passengers should be able to travel door-to-door in Europe within 4 hours.
Passenger mobility is obviously the ultimate goal of the air transport system, which mission is to transport passengers and freight, not airplanes. However, punctuality is currently mostly measured as aircraft operations performance. Moreover, most air traffic management technology improvements are targeting aircraft punctuality and not passenger punctuality. Passenger punctuality depends critically on passenger connectivity, as a missed connection impacts very negatively in passenger mobility performance.
Increasing the predictability of air transport operations has limits. Not only meteorological conditions can affect the punctuality but also countless operational hazards impact the air traffic management system. Making the system adaptable to changes in the operational conditions, capable of re-configuring itself to accommodate to a new scenario seems a better approach than trying to make the system robust, which ultimately could be too expensive or impossible.
Studying how different mechanisms improve the adaptability of the system is a complex problem. On one hand, it is a challenge to design a procedure that provides adaptability without impacting other performance metrics of the system. On the other hand, complex mechanisms usually require dedicated simulation frameworks, capable of modelling realistically a large number of parameters as well as providing a performance framework capable of evaluating in detail (e.g. beyond simple statistical properties) how the system adapts to the new conditions and how those mechanisms target a performance goal.
The CASSIOPEIA DCI-4HD2D project extension studied how changing the trajectory of each aircraft to either minimise fuel consumption or to minimise time to destination can be used as a adaptability mechanism, to work together with other ATM improvements, to address passenger connectivity.
Understanding how this mechanism, known as Dynamic Cost Indexing (DCI), increases the adaptability of the system, required the analysis, design and implementation of a complex software system as a collection of interacting, autonomous agents.
This document reports on the cases of study selected and the analysis of the outcome of the simulations performed, assessing how DCI contributes to passenger connectivity and, ultimately, to passenger mobility improvement
One Dimensional Magnetized TG Gas Properties in an External Magnetic Field
With Girardeau's Fermi-Bose mapping, we have constructed the eigenstates of a
TG gas in an external magnetic field. When the number of bosons is
commensurate with the number of potential cycles , the probability of this
TG gas in the ground state is bigger than the TG gas raised by Girardeau in
1960. Through the comparison of properties between this TG gas and Fermi gas,
we find that the following issues are always of the same: their average value
of particle's coordinate and potential energy, system's total momentum,
single-particle density and the pair distribution function. But the reduced
single-particle matrices and their momentum distributions between them are
different.Comment: 6 pages, 4 figure
CASSIOPEIA D4.3 - case study 3 report: hub connectivity-driven variable aircraft speeds
This document reports on how the CASSIOPEIA agent-based model has been developed, through a case study, to explore the use of dynamic cost indexing on flights arriving at a major European hub airport. A scenario that simulated many flights using dynamic cost indexing to recover delay to a residual of 10 minutes resulted in a considerable average cost saving achieved per flight
Limited sensitivity analysis of ARAIM availability for LPV-200 over Australia using real data
Current availability of Advanced Receiver Autonomous Integrity Monitoring (ARAIM) for LPV-200 in aviation is experimentally investigated using real navigation data and GPS measurements collected at 60 stations across Australia. ARAIM algorithm and fault probabilities were first discussed. Availability sensitivity analysis due to changes in the elevation mask angle and the error model parameters URA, URE, and nominal biases for integrity and accuracy used for computation of the protection level is presented. It is shown that incorporation of other GNSS constellation with GPS in ARAIM is needed to achieve LPV-200 Australia wide. The inclusion of BeiDou with GPS at two tests sites in Western and Eastern Australia demonstrates the promising potential of achieving this goal
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