5,973 research outputs found
Grushin problems and control theory: Formulation and examples
In this paper we give a new formulation of an abstract control problem in
terms of a Grushin problem, so that we will reformulate all notions of
controllability, observability and stability in a new form that gives readers
an easy interpretation of these notions
Stability of higher order singular points of Poisson manifolds and Lie algebroids
We study the stability of singular points for smooth Poisson structures as
well as general Lie algebroids. We give sufficient conditions for stability
lying on the first (not necessarily linear) approximation of the given Poisson
structure or Lie algebroid at a singular point. The main tools used here are
the classical Lichnerowicz-Poisson cohomology and the deformation cohomology
for Lie algebroids recently introduced by Crainic and Moerdijk. We also provide
several examples of stable singular points of order for Poisson
structures and Lie algebroids. Finally, we apply our results to pre-symplectic
leaves of Dirac manifolds.Comment: corrected typo
On the local structure of Dirac manifolds
We give a local normal form for Dirac structures. As a consequence, we show
that the dimensions of the pre-symplectic leaves of a Dirac manifold have the
same parity. We also show that, given a point of a Dirac manifold ,
there is a well-defined transverse Poisson structure to the pre-symplectic leaf
through . Finally, we describe the neighborhood of a pre-symplectic leaf
in terms of geometric data. This description agrees with that given by Vorobjev
for the Poisson caseComment: minor correction
Optimization of blasting parameters in open cast quarries of El Hassa-Bouira (Northern Algeria)
In recent years, Algeria has known a rapid growth in the construction projects, such as: buildings, roads, and infrastructure, which increased the demand for aggregates production in quarries. However, vibrations and noises generated by blasting operations have a negative impact on the residents living nearby. For this reason, blast tests were performed in the open cast quarries of the company Sarl El Hassa-Bouira (Northern Algeria) using instantaneous electric detonators (IED), micro delays (MDD) and delays (EDD) to minimize the instantaneous load. We also minimized noise and vibration during the blasting. A seismograph allowed us to take further measurements
VB-Courant algebroids, E-Courant algebroids and generalized geometry
In this paper, we first discuss the relation between VB-Courant algebroids
and E-Courant algebroids and construct some examples of E-Courant algebroids.
Then we introduce the notion of a generalized complex structure on an E-Courant
algebroid, unifying the usual generalized complex structures on
even-dimensional manifolds and generalized contact structures on
odd-dimensional manifolds. Moreover, we study generalized complex structures on
an omni-Lie algebroid in detail. In particular, we show that generalized
complex structures on an omni-Lie algebra \gl(V)\oplus V correspond to
complex Lie algebra structures on V.Comment: 19 page
A Reinforcement Learning-driven Translation Model for Search-Oriented Conversational Systems
Search-oriented conversational systems rely on information needs expressed in
natural language (NL). We focus here on the understanding of NL expressions for
building keyword-based queries. We propose a reinforcement-learning-driven
translation model framework able to 1) learn the translation from NL
expressions to queries in a supervised way, and, 2) to overcome the lack of
large-scale dataset by framing the translation model as a word selection
approach and injecting relevance feedback in the learning process. Experiments
are carried out on two TREC datasets and outline the effectiveness of our
approach.Comment: This is the author's pre-print version of the work. It is posted here
for your personal use, not for redistribution. Please cite the definitive
version which will be published in Proceedings of the 2018 EMNLP Workshop
SCAI: The 2nd International Workshop on Search-Oriented Conversational AI -
ISBN: 978-1-948087-75-
- …
