9,518 research outputs found
Transient situations in traffic flow: Modelling the Mexico City Cuernavaca Highway
In this paper a recent variable anticipation cellular automata model for
single-lane traffic flow is extended to analyze the situation of free and
congested flow in the Highway from Mexico City to Cuernavaca. This highway
presents free flow in standard days; but in the returning day of long weekends
or holidays it exhibits congested flow and in rush hours jamming appears. We
illustrate how our CA model for traffic flow can deal appropriately with
transient situations and can be used to search new alternatives that allow to
improve the traffic flow in Mexican highways.Comment: Paper accepted to be published in the Proceedings of Second Mexican
Meeting on Mathematical and Experimental Physics (September 2004), El Colegio
Nacional, Mexico City, Mexic
Towards Informative Statistical Flow Inversion
This is the accepted version of 'Towards Informative Statistical Flow Inversion', archived originally at arXiv:0705.1939v1 [cs.NI] 14 May 2007.A problem which has recently attracted research attention is that of estimating the distribution of flow sizes in internet traffic. On high traffic links it is sometimes impossible to record every packet. Researchers have approached the problem of estimating flow lengths from sampled packet data in two separate ways. Firstly, different sampling methodologies can be tried to more accurately measure the desired system parameters. One such method is the sample-and-hold method where, if a packet is sampled, all subsequent packets in that flow are sampled. Secondly, statistical methods can be used to ``invert'' the sampled data and produce an estimate of flow lengths from a sample. In this paper we propose, implement and test two variants on the sample-and-hold method. In addition we show how the sample-and-hold method can be inverted to get an estimation of the genuine distribution of flow sizes. Experiments are carried out on real network traces to compare standard packet sampling with three variants of sample-and-hold. The methods are compared for their ability to reconstruct the genuine distribution of flow sizes in the traffic
The turnstile mechanism across the Kuroshio current: analysis of dynamics in altimeter velocity fields
In this article we explore the ability of dynamical systems tools to describe
transport in oceanic flows characterized by data sets measured from satellite.
In particular we have studied the geometrical skeleton describing transport in
the Kuroshio region. For this purpose we have computed special hyperbolic
trajectories, recognized as distinguished hyperbolic trajectories, that act as
organizing centres of the flow. We have computed their stable and unstable
manifolds, and they reveal that the turnstile mechanism is at work during
several spring months in the year 2003 across the Kuroshio current. We have
found that near the hyperbolic trajectories takes place a filamentous transport
front-cross the current that mixes waters at both sides.Comment: Nonlinear Processes in Geophysics 17, 2010 (in press
Tradable Permits Under Threat to Manage Nonpoint Source Pollution
In this article we treat the problem of nonpoint source pollution as a problem of moral hazard in group. To solve this kind of problem we consider a group performance based tax coupled to tradable permits market. The tax is activated if the group fails to meet the ambient standard. So the role of the tax is to provide an incitation to ensure that the agents provide the abatement level necessary to achieve the standard. The role of the tradable permits market is to distribute effectively this abatement level through the price of the permits which rises with the exchange of the permits.nonpoint source pollution, ambient tax, tradable permits market, Environmental Economics and Policy,
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