37,372 research outputs found
AutonoVi: Autonomous Vehicle Planning with Dynamic Maneuvers and Traffic Constraints
We present AutonoVi:, a novel algorithm for autonomous vehicle navigation
that supports dynamic maneuvers and satisfies traffic constraints and norms.
Our approach is based on optimization-based maneuver planning that supports
dynamic lane-changes, swerving, and braking in all traffic scenarios and guides
the vehicle to its goal position. We take into account various traffic
constraints, including collision avoidance with other vehicles, pedestrians,
and cyclists using control velocity obstacles. We use a data-driven approach to
model the vehicle dynamics for control and collision avoidance. Furthermore,
our trajectory computation algorithm takes into account traffic rules and
behaviors, such as stopping at intersections and stoplights, based on an
arc-spline representation. We have evaluated our algorithm in a simulated
environment and tested its interactive performance in urban and highway driving
scenarios with tens of vehicles, pedestrians, and cyclists. These scenarios
include jaywalking pedestrians, sudden stops from high speeds, safely passing
cyclists, a vehicle suddenly swerving into the roadway, and high-density
traffic where the vehicle must change lanes to progress more effectively.Comment: 9 pages, 6 figure
An optimization model for line planning and timetabling in automated urban metro subway networks
In this paper we present a Mixed Integer Nonlinear Programming model that we
developed as part of a pilot study requested by the R&D company Metrolab in
order to design tools for finding solutions for line planning and timetable
situations in automated urban metro subway networks. Our model incorporates
important factors in public transportation systems from both, a cost-oriented
and a passenger-oriented perspective, as time-dependent demands, interchange
stations, short-turns and technical features of the trains in use. The incoming
flows of passengers are modeled by means of piecewise linear demand functions
which are parameterized in terms of arrival rates and bulk arrivals. Decisions
about frequencies, train capacities, short-turning and timetables for a given
planning horizon are jointly integrated to be optimized in our model. Finally,
a novel Math-Heuristic approach is proposed to solve the problem. The results
of extensive computational experiments are reported to show its applicability
and effectiveness to handle real-world subway networksComment: 30 pages, 6 figures, 9 table
Route Planning in Transportation Networks
We survey recent advances in algorithms for route planning in transportation
networks. For road networks, we show that one can compute driving directions in
milliseconds or less even at continental scale. A variety of techniques provide
different trade-offs between preprocessing effort, space requirements, and
query time. Some algorithms can answer queries in a fraction of a microsecond,
while others can deal efficiently with real-time traffic. Journey planning on
public transportation systems, although conceptually similar, is a
significantly harder problem due to its inherent time-dependent and
multicriteria nature. Although exact algorithms are fast enough for interactive
queries on metropolitan transit systems, dealing with continent-sized instances
requires simplifications or heavy preprocessing. The multimodal route planning
problem, which seeks journeys combining schedule-based transportation (buses,
trains) with unrestricted modes (walking, driving), is even harder, relying on
approximate solutions even for metropolitan inputs.Comment: This is an updated version of the technical report MSR-TR-2014-4,
previously published by Microsoft Research. This work was mostly done while
the authors Daniel Delling, Andrew Goldberg, and Renato F. Werneck were at
Microsoft Research Silicon Valle
Network harness: bundles of routes in public transport networks
Public transport routes sharing the same grid of streets and tracks are often
found to proceed in parallel along shorter or longer sequences of stations.
Similar phenomena are observed in other networks built with space consuming
links such as cables, vessels, pipes, neurons, etc. In the case of public
transport networks (PTNs) this behavior may be easily worked out on the basis
of sequences of stations serviced by each route. To quantify this behavior we
use the recently introduced notion of network harness. It is described by the
harness distribution P(r,s): the number of sequences of s consecutive stations
that are serviced by r parallel routes. For certain PTNs that we have analyzed
we observe that the harness distribution may be described by power laws. These
power laws observed indicate a certain level of organization and planning which
may be driven by the need to minimize the costs of infrastructure and secondly
by the fact that points of interest tend to be clustered in certain locations
of a city. This effect may be seen as a result of the strong interdependence of
the evolutions of both the city and its PTN.
To further investigate the significance of the empirical results we have
studied one- and two-dimensional models of randomly placed routes modeled by
different types of walks. While in one dimension an analytic treatment was
successful, the two dimensional case was studied by simulations showing that
the empirical results for real PTNs deviate significantly from those expected
for randomly placed routes.Comment: 12 pages, 24 figures, paper presented at the Conference ``Statistical
Physics: Modern Trends and Applications'' (23-25 June 2009, Lviv, Ukaine)
dedicated to the 100th anniversary of Mykola Bogolyubov (1909-1992
Preliminary Results of a Multiagent Traffic Simulation for Berlin
This paper provides an introduction to multi-agent traffic simulation. Metropolitan regions can consist of several million inhabitants, implying the simulation of several million travelers, which represents a considerable computational challenge. We reports on our recent case study of a real-world Berlin scenario. The paper explains computational techniques necessary to achieve results. It turns out that the difficulties there, because of data availability and because of the special situation of Berlin after the re-unification, are considerably larger than in previous scenarios that we have treated
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