3,182 research outputs found
BEACON - D5.1 First tactical model and results
The deliverable presents the results obtained with the help of the Mercury simulator in order to estimate the efficiency and equitability of hotspot resolution mechanisms defined in D3.1 and tested on a small-scale simulator in D4.2. To this end, fast-time games are defined, with a central optimiser implementing the mechanisms computing the final flight/slot allocation. The game is played by agents representing the airlines present in the regulation, and who are tasked with sending information to the central optimiser regarding their own costs, in order for the latter to find the best possible allocation cost-wise. The deliverable defines the various games possible, combining different types of central optimisers and different types of agents, taking into account various degrees of rationality and behavioural biases for the decisions of the latter. The deliverable presents a theoretical framework for these behaviours, highly simplified but implementable in simple simulations.
Different results with these simulations are presented. First, it is found that the approximation process used by airlines to communicate their costs to the optimiser has a major effect on the efficiency of the mechanisms. Second, it is found that, due to the variance of the regulation structure and the approximation issues, defining a performant rational agent is difficult. Despite this fact, the deliverable shows how one of the mechanisms (credit mechanism) was calibrated, including the rationality of agents in the corresponding game. It then shows the detrimental impact of the presence of rational agents â as opposed to honest ones â on the efficiency of two relevant optimisers, including the credit mechanism, as well as the impact of behavioural biases. Finally, it compares the aggregated gains potentially made with the various mechanisms in terms of efficiency and equit
Network-wide assessment of 4D trajectory adjustments using an agent-based model
This paper presents results from the SESAR ER3 Domino project. It focuses on an ECAC-wide assessment of two 4D-adjustment mechanisms, implemented separately and conjointly. These reflect flight behaviour en-route and at-gate, optimising given (cost) objective functions. New metrics designed to capture network effects are used to analyse the results of a microscopic, agent based model. The results show that some implementations of the mechanisms allow the protection of the network from âdominoâ effects. Airlines focusing on costs may trigger additional side-effects on passengers, displaying, in some instances, clear trade-offs between passenger- and flight-centric metrics
Fiscal policy in Mediterranean countries â developments, structures and implications for monetary policy
Southern and eastern Mediterranean countries have many fiscal challenges in common with other emerging market and mature economies concerning deficit and debt reduction and the maintenance of fiscal discipline. However, most countries in the region also face some specific fiscal issues, such as relatively high public debt, dependence on some form or another of donor dependence or concessional financing, high budgetary exposure to fluctuations in hydrocarbon prices, high defence expenditure and weak tax bases. Against this background, this paper reviews fiscal developments and fiscal policy issues in the ten countries that are participants or observers in the EUâs Barcelona process. The main focus is on the implications of these developments and issues for macroeconomic stability, given that countries in the region have made considerable progress in terms of macroeconomic stabilisation over the last two decades, which is reflected in particular in lower inflation rates. The analysis distinguishes between non-oil-producing and oil-producing countries in the region, as they exhibit different fiscal features and are confronted with different challenges. In the case of non-oil-producing countries, the key challenges stem from high deficits and debt levels, including implicit and contingent liabilities, notwithstanding some progress in fiscal consolidation in most of these countries over the last years. In the case of oil-producing countries, whose fiscal situation has significantly improved in recent years in the wake of high oil prices, the key challenges for fiscal management stem from the heavy reliance on an exhaustible source of revenues and a large exposure to fluctuations in international hydrocarbon prices. A shock originating from â or being transmitted via and exacerbated by â the fiscal sector appears to be the single most important macroeconomic risk in many countries.
Strategic allocation of flight plans in air traffic management: an evolutionary point of view
We present a simplified model of the strategic allocation of trajectories in a generic airspace for commercial flights.
In this model, two types of companies, characterised by different cost functions and different strategies, compete for the allocation of trajectories in the airspace. With an analytical model and numerical simulations, we show that the relative advantage of the two populations -- companies -- depends on external factors like traffic demand as well as on the composition of the population. We show that there exists a stable equilibrium state which depends on the traffic demand. We also show that the equilibrium solution is not the optimal at the global level, but rather that it tends to favour one of the two business models -- the archetype for low-cost companies.
Finally, linking the cost of allocated flights with the fitness of a company, we study the evolutionary dynamics of the system, investigating the fluctuations of population composition around the equilibrium and the speed of convergence towards it. We prove that in the presence of noise due to finite populations, the equilibrium point is shifted and is reached more slowly
D6.1 Intermediate concept assessment report
This Technical Report presents an interim synthesis of the stakeholders' input and the specifications stemming from internal discussions and the stakeholder workshop. It presents the main issues related to the concepts attached to the mechanisms selected in D3.1, for instance in terms of market mechanism design. Following the output of these discussions, some specifications for the project, and sometimes for the models, are laid out
Fiscal policy challenges in oil-exporting countries â a review of key issues.
Fiscal policy choices have a particularly significant impact on economic performance in oil-exporting countries, owing to the importance of the oil sector in the economy and the fact that in most countries oil revenues accrue to the government. At the same time, fiscal policy in oil-centred economies s facing specific challenges, both in the long run, as regards intergenerational equity and fiscal sustainability, and in the short run, as regards macroeconomic stabilisation and fiscal planning. Institutional responses to the specific fiscal challenges in oil-exporting countries involve conservative oil price assumptions in the budget, the establishment of oil stabilisation and savings funds and fiscal rules. Fiscal policy in most oil-exporting countries has been expansionary over the past years in the wake of high oil prices. Fiscal expansion has added to inflationary pressure, and monetary policy has been constrained in tackling inflation as a result of prevailing exchange rate regimes. While, in this context, fiscal policy is the major tool for macroeconomic stabilisation, it has faced competing objectives and considerations. Cyclical considerations would have warranted fiscal restraint, but, in times of high oil prices, pressures to increase public spending have been mounting. Such pressures stem from primarily distribution-related considerations, development-related spending needs (e.g. in the areas of physical and social infrastructure) and international considerations in the context of, for example, global imbalances. The sharp fall in oil prices since mid-2008 has brought to the fore a different question â whether oil exporters can sustain spending levels reached in previous years. JEL Classification: E62, E63, H30, H60, Q32, Q38.Fiscal policy, oil-exporting countries, inflation, global imbalances.
Adversity and resilience: a case study of crisis management in a tourist-reliant destination
Few would dispute the assertion that the twenty-first century has already begun with significant obstacles for the burgeoning tourism industry. The September 11 hijackings, Afghanistan and the continuing war in Iraq, the Bali bombings, SARS, the bird flu, the Madrid train attacks, US hurricanes, European floods and most recently the devastating South Asian tsunami have each added greater uncertainty to the pursuit of travel and leisure. While the very nature of tourism and its capacity to offer so many choices amd alternatives may have meant that the overall eddect on global tourism figures has been mimimal - many individual destinations can ill afford a significant or sustained loss of consumer confidence
- âŠ