1,720,963 research outputs found
An Optimisation-simulation Framework for the Delay Management Problem in Public Transportation
No full text
A Network Pricing Formulation for the revenue maximization of European Air Navigation Service Providers
No full textIn Europe, all Air Navigation Service Providers (ANSPs) finance their activities by charging airlines to use their airspace. These ‘en route charges’ usually account for a significant fraction of the cost of a flight, and they can therefore influence the route choice: airlines may decide to fly longer routes to avoid countries with higher charges. Then ANSPs’ traffic and revenue do depend on the charge they impose on their own airspace. It follows that if ANSPs look for the maximization of their revenues, they must choose an optimal charge to impose on their airspace. We show that this optimal charge can be identified through a Network Pricing Problem formulation in the form of Bilevel Programming where the leader (i.e. the ANSP) owns a set of arcs (the airways in its national airspace) and charges the commodities (i.e. the flights) passing through them. As the en route charges are proportional to a Unit Rate value fixed by the ANSP, by exploiting the structure of the problem we propose an exact algorithm to compute the optimal Unit Rate and apply it to a case study
En route charges for ANSP revenue maximization
No full textIn Europe, all Air Navigation Service Providers
(ANSPs) finance their activities by charging airlines using their
airspace. These ‘en route charges’ usually account for a significant
part of the cost of a flight, and they can therefore influence
the route choice: airlines may decide to fly longer routes to avoid
countries with higher charges. If ANSPs want to maximize their
revenues, they must choose the optimal charge to impose on their
airspace. We show that this optimal charge can be identified
through a Network Pricing Problem (NPP) formulation in the
form of Bilevel Programming where the leader (i.e. the ANSP)
owns a set of arcs (the airways in its national airspace) and
charges the commodities (i.e. the flights) passing through them.
As the en route charges are proportional to a Unit Rate value
fixed by the ANSP, we are able to apply a similar methodology
as in the case of a single toll arc for the NPP. By exploiting
the structure of the problem, we propose an exact algorithm
to compute the optimal Unit Rate and apply it to a case study
relying on real air traffic data and realistic flight cost figures
Exact and Heuristic Solution Techniques for Mixed-Integer Quantile Minimization Problems
No full textA Lower Bound for the Internet Protocol Network Design Problem
No full textThe Internet Protocol (IP) Network Design problem (IPND) concerns the topological optimization of an IP telecommunication network. A set of nodes is given together with a set of traffic demands between pairs of nodes. Traffic demands are routed according to the Open Shortest Path First (OSPF) protocol with Equal commodity Multi-flow (ECM) splitting, based on a set of given routing weights. An integer number of capacitated devices can be configured between pairs of nodes to route all the traffic, thus giving the cost of the network. The IPND problem consists of determining a minimum cost network topology and capacity assignment such that all traffic demands are satisfied. In this work, we present a Mixed Integer Linear Programming (MILP) model and we investigate a Branch-and-Cut algorithm to derive a lower bound for IPND. Some preliminary computational results and hints for further research are also
presented
On Fishman's sampling plan for computing network reliability
No full textinfo:eu-repo/semantics/publishe
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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