1,829 research outputs found
A comparison of digital transmission techniques under multichannel conditions at 2.4 GHz in the ISM BAND
In order to meet the observation quality criteria of micro-UAVs, and particularly in the context of the « Trophée Micro-Drones », ISAE/SUPAERO is studying technical solutions to transmit a high data rate from a video payload onboard a micro-UAV. The laboratory has to consider the impact of multipath and shadowing effects on the emitted signal. Therefore fading resistant transmission techniques are considered. This techniques paper have to reveal an optimum trade-off between three parameters, namely: the characteristics of the video stream, the complexity of the modulation and coding scheme, and the efficiency of the transmission, in term of BER
On the Marginal Cost of Road Congestion: an Evaluation Method with Application to the Paris Region
The paper analyzes the sensitivity of the marginal congestion cost on a roadway network to the level of aggregation in space, from utmost disaggregate to utmost aggregate. Simulation and aggregation are based on a static network assignment model.Marginal cost ; Road congestion ; Cost aggregation ; Congestion indicator ; Assignment model
Topological graph polynomials and quantum field theory, Part II: Mehler kernel theories
We define a new topological polynomial extending the Bollobas-Riordan one,
which obeys a four-term reduction relation of the deletion/contraction type and
has a natural behavior under partial duality. This allows to write down a
completely explicit combinatorial evaluation of the polynomials, occurring in
the parametric representation of the non-commutative Grosse-Wulkenhaar quantum
field theory. An explicit solution of the parametric representation for
commutative field theories based on the Mehler kernel is also provided.Comment: 58 pages, 23 figures, correction in the references and addition of
preprint number
Algorithmic Aspects of Switch Cographs
This paper introduces the notion of involution module, the first
generalization of the modular decomposition of 2-structure which has a unique
linear-sized decomposition tree. We derive an O(n^2) decomposition algorithm
and we take advantage of the involution modular decomposition tree to state
several algorithmic results. Cographs are the graphs that are totally
decomposable w.r.t modular decomposition. In a similar way, we introduce the
class of switch cographs, the class of graphs that are totally decomposable
w.r.t involution modular decomposition. This class generalizes the class of
cographs and is exactly the class of (Bull, Gem, Co-Gem, C_5)-free graphs. We
use our new decomposition tool to design three practical algorithms for the
maximum cut, vertex cover and vertex separator problems. The complexity of
these problems was still unknown for this class of graphs. This paper also
improves the complexity of the maximum clique, the maximum independant set, the
chromatic number and the maximum clique cover problems by giving efficient
algorithms, thanks to the decomposition tree. Eventually, we show that this
class of graphs has Clique-Width at most 4 and that a Clique-Width expression
can be computed in linear time
On the Marginal Cost of Road Congestion: an Evaluation Method with Application to the Paris Region
International audienceThe paper analyzes the sensitivity of the marginal congestion cost on a roadway network to the level of aggregation in space, from utmost disaggregate to utmost aggregate. Simulation and aggregation are based on a static network assignment model
On large size problems of dynamic network assignment and traffic equilibrium: Computational principles and application to Paris road network
25 pagesInternational audienceThe paper reports on the algorithmic treatment and computer implementation of a macroscopic dynamic traffic assignment model called LADTA. The modelling assumptions and the mathematical analysis founding the model are first stated. Detailed descriptions of the main algorithms are given, together with the principles of the computer implementation. It is shown how the design of the software architecture allows for distributed computation of a traffic assignment. The practical ability of this implementation to tackle with large size networks is illustrated by an application to the Paris road network, which comprises around 1,300 zones and 39,000 links
Algorithmic Aspects of a General Modular Decomposition Theory
A new general decomposition theory inspired from modular graph decomposition
is presented. This helps unifying modular decomposition on different
structures, including (but not restricted to) graphs. Moreover, even in the
case of graphs, the terminology ``module'' not only captures the classical
graph modules but also allows to handle 2-connected components, star-cutsets,
and other vertex subsets. The main result is that most of the nice algorithmic
tools developed for modular decomposition of graphs still apply efficiently on
our generalisation of modules. Besides, when an essential axiom is satisfied,
almost all the important properties can be retrieved. For this case, an
algorithm given by Ehrenfeucht, Gabow, McConnell and Sullivan 1994 is
generalised and yields a very efficient solution to the associated
decomposition problem
A Note On Computing Set Overlap Classes
Let be a finite set of elements and a family of subsets of Two sets and of
overlap if and Two sets
are in the same overlap class if there is a series of
sets of in which each overlaps. In this note, we focus
on efficiently identifying all overlap classes in
time. We thus revisit the clever algorithm of Dahlhaus of which we give a clear
presentation and that we simplify to make it practical and implementable in its
real worst case complexity. An useful variant of Dahlhaus's approach is also
explained
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