Abstract

Proceeding of: IEEE International Conference on Communications (ICC 2018) Enterprise Networking has a strong set of requirements in terms of resiliency, reliability and resources usage. With current approaches being based on monolithic and expensive infrastructures using dedicated overlay links, providers are moving to more economical hybrid solutions that encompass private dedicated links with public/regular Internet connections. However, these usually rely on complex, hardware-dependent and/or proprietary Traffic Engineering (TE) solutions, which are computationally costly, in particular for the forwarding nodes. In this paper, we propose SEMPER: a lightweight TE solution based on MP-TCP that, in contrast to other TE solutions, moves the complexity to the endpoints of the connection, and relieves the forwarding elements from complex operations or even maintaining state. As our evaluation shows, SEMPER efficiently makes use of all available paths between the endpoints while maintaining fairness, and properly adapts to variations on the available capacity. This work has been partly supported by the H2020 5GMoNArch project (grant agreement 761445), and by the Madrid Regional Government through the TIGRE5-CM program (S2013/ICE-2919).

Abstract

Free route airspace permits users to freely plan a route between defined entry and exit waypoints, with the possibility of routing via intermediate points. Flights flying in a free route area remain subject to air traffic control (ATC) for separation provision. This research evaluates an extreme future scenario of free route implementation across Europe. We consider the complete upper airspace of the European Civil Aviation Conference (ECAC) area as a unique airspace block configured with free route. The paper is centered in investigating the benefits for the airspace users, and in the study of possible increments of complexity of such configuration. In this research, fast time simulations are carrying out to discover how much flight time, fuel and distance aircraft can save with this free route configuration. In the other side, the paper explains the evolution of conflicts derived from potential separation losses between aircraft in this new environment. Separation losses in free route can emerge at any point of the airspace, which can require greater effort for solving them in comparison with fixed airways configuration, where conflicts are usually found in well-known airways intersections. The airspace configurations modelled in this study are the fixed airways structure, named as Current, and the future scenario, named as EUROFRA, where new navigation points are added. This research studies the advantages and difficulties that a large scale application of the free route concept can bring to the European airspace. Peer Reviewed

Abstract

The understanding and conceptualization of cities and its constituent systems such as transportation and healthcare as open and complex is shifting the debates around the technical and communicative rationales of planning. Viewing cities in a holistic manner presents methodological challenges, where our understanding of complexity is applied in a tangible fashion to planning processes. Bridging the two rationales in the tools and methodologies of planning is necessary for the emergence of a 'non-linear rationality' of planning, one that accounts for and is premised upon complexity. Simulations representing complex systems provide evidence and support for planning, and have the potential to serve as an interface between the more abstract and political decision making and the material city systems. Moving beyond current planning methods, this thesis explores the role of simulations in planning. Recognizing the need for holistic representations, the thesis integrates multiple disparate simulations into a holistic whole achieving complex representations of systems. These representations are then applied and studied in an interactive environment to address planning problems in different contexts. The thesis contributes an approach towards the development of complex representations of systems; improvements on participatory methods to integrate computational simulations; a nuanced understanding of the relative value of simulation constructs; technologies and frameworks that facilitate the easy development of integrated simulations that can support participatory planning processes. The thesis develops contributions through experiments which involved problems and stakeholders from real world systems. The approach towards development of integrated simulations is realized in an open source framework. The framework creates computationally efficient, scalable and interactive simulations of complex systems, which used in a participatory manner delivers tangible plans and designs. "p"QC 20170602

Abstract

In the SESAR traffic growth predictions, traffic complexity will become an issue that the current Air Traffic Management organization is not able to handle. The 4D trajectory concept offers new perspectives for deconflicting the traffic by ground-holding aircraft before they take-off. This paper studies the possible complexity reduction achievable by optimizing the aircraft take-off times. Therefore a simple model is introduced to detect pairwise 3D possible conflicts and define conflicting take-off time differences. Two resolution algorithms are tested on a real traffic data sample collected in the French airspace. The first one is based on a Constraint Programming model of the problem and ensures the optimality of the maximum delay required to solve every conflict. The second one uses an evolutionary computation algorithm to minimize the mean delay among the aircraft population. A sliding window model is introduced to reduce the size of the problem and to regularly update the current situation. Experimental results performed in the French airspace with fast time simulation show that with perfect 4D trajectory, every conflict over flight level 290 can be solved by delaying less than a quarter of the traffic within a range of delays varying from 1 to 90 minutes and a mean delay of 4 minutes. The Constraint Programming approach gives better results than the evolutionary computation approach. Adding uncertainty around 4D trajectories dramatically degrades the results.