19,615 research outputs found
Priority-based intersection management with kinodynamic constraints
We consider the problem of coordinating a collection of robots at an
intersection area taking into account dynamical constraints due to actuator
limitations. We adopt the coordination space approach, which is standard in
multiple robot motion planning. Assuming the priorities between robots are
assigned in advance and the existence of a collision-free trajectory respecting
those priorities, we propose a provably safe trajectory planner satisfying
kinodynamic constraints. The algorithm is shown to run in real time and to
return safe (collision-free) trajectories. Simulation results on synthetic data
illustrate the benefits of the approach.Comment: to be presented at ECC2014; 6 page
On the Robustness of the h-index: a mathematical approach
The h-index is an index recently proposed by Hirsch (2005) to measure scientific achievement by individual scholars. It is a compound measure of publications and citations. We show the robustness of this index. This means that h-index increases with both the number of publications and the number of citations only when these numbers are significant.
Back-pressure traffic signal control with unknown routing rates
The control of a network of signalized intersections is considered. Previous
works proposed a feedback control belonging to the family of the so-called
back-pressure controls that ensures provably maximum stability given
pre-specified routing probabilities. However, this optimal back-pressure
controller (BP*) requires routing rates and a measure of the number of vehicles
queuing at a node for each possible routing decision. It is an idealistic
assumption for our application since vehicles (going straight, turning
left/right) are all gathered in the same lane apart from the proximity of the
intersection and cameras can only give estimations of the aggregated queue
length. In this paper, we present a back-pressure traffic signal controller
(BP) that does not require routing rates, it requires only aggregated queue
lengths estimation (without direction information) and loop detectors at the
stop line for each possible direction. A theoretical result on the Lyapunov
drift in heavy load conditions under BP control is provided and tends to
indicate that BP should have good stability properties. Simulations confirm
this and show that BP stabilizes the queuing network in a significant part of
the capacity region.Comment: accepted for presentation at IFAC 2014, 6 pages. arXiv admin note:
text overlap with arXiv:1309.648
Multiplexed holographic transmission gratings recorded in holographic polymer-dispersed liquid crystals: static and dynamic studies
The optimization of the experimental parameters of two multiplexed holographic transmission gratings recorded in holographic polymer-dispersed liquid crystals is investigated. Two methods are used to record the holograms: simultaneous and sequential multiplexing. These two processes are optimized to produce two multiplexed Bragg gratings that have the same and the highest possible diffraction efficiencies in the first order. The two methods show similar results when suitable recording parameters are used. The parameters of the recorded gratings (mainly the refractive-index modulation) are retrieved by use of an extension of the rigorous coupled-wave theory to multiplexed gratings. Finally, the response of the holograms to an electric field is studied. We demonstrate few coupling effects between the behavior of both gratings, and we expect a possibility of switching from one grating to the other
Higgs couplings: disentangling New Physics with off-shell measurements
After the discovery of a scalar resonance, resembling the Higgs boson, its
couplings have been extensively studied via the measurement of various
production and decay channels on the invariant mass peak. Recently, it has been
suggested the possibility to use off-shell measurements: in particular, CMS has
published results based on the high- invariant mass cross section of the
process , which contains the contribution of the Higgs. While this
measurement has been interpreted as a constraint on the Higgs width after very
specific assumptions are taken on the Higgs couplings, in this letter we show
that a much more model-independent interpretation is possible.Comment: 6pp, 1 figur
Higgs couplings beyond the Standard Model
We consider the Higgs boson decay processes and its production, and provide a
parameterisation tailored for testing models of new physics beyond the Standard
Model. We also compare our formalism to other existing parameterisations based
on scaling factors in front of the couplings and to effective Lagrangian
approaches. Different formalisms allow to best address different aspects of the
Higgs boson physics. The choice of a particular parameterisation depends on a
non-obvious balance of quantity and quality of the available experimental data,
envisaged purpose for the parameterisation and degree of model independence,
importance of the radiative corrections, scale at which new particles appear
explicitly in the physical spectrum. At present only simple parameterisations
with a limited number of fit parameters can be performed, but this situation
will improve with the forthcoming experimental LHC data. Detailed fits can only
be performed by the experimental collaborations at present, as the full
information on the different decay modes is not completely available in the
public domain. It is therefore important that different approaches are
considered and that the most detailed information is made available to allow
testing the different aspects of the Higgs boson physics and the possible hints
beyond the Standard Model.Comment: 22 pages, 5 figures, 5 tables. This version is an update including
the most recent Higgs data and new fits to two extra model
Labor market dynamics when effort depends on wage growth comparisons
We present an efficiency wage model in which workers'' effort depends on the level and on the growth rate of their wage relative to an alternative wage. Using data for four countries (US, UK, FR, GY), the implications of the model are examined and are found to be in accordance with the information in the non-stationary data. The restrictions implied by the model dynamics are not rejected by the data. Moreover the structural parameters are found to be constant through time, indicating that, although very simple, the model is likely to be robust to the Lucas critique. One interesting result is that the workers'' effort depends less on relative wages growth and more on relative wage levels in the US than in the three European countries analyzed.mathematical economics and econometrics ;
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