5,842 research outputs found
Fast object detection in compressed JPEG Images
Object detection in still images has drawn a lot of attention over past few
years, and with the advent of Deep Learning impressive performances have been
achieved with numerous industrial applications. Most of these deep learning
models rely on RGB images to localize and identify objects in the image.
However in some application scenarii, images are compressed either for storage
savings or fast transmission. Therefore a time consuming image decompression
step is compulsory in order to apply the aforementioned deep models. To
alleviate this drawback, we propose a fast deep architecture for object
detection in JPEG images, one of the most widespread compression format. We
train a neural network to detect objects based on the blockwise DCT (discrete
cosine transform) coefficients {issued from} the JPEG compression algorithm. We
modify the well-known Single Shot multibox Detector (SSD) by replacing its
first layers with one convolutional layer dedicated to process the DCT inputs.
Experimental evaluations on PASCAL VOC and industrial dataset comprising images
of road traffic surveillance show that the model is about faster than
regular SSD with promising detection performances. To the best of our
knowledge, this paper is the first to address detection in compressed JPEG
images
The radius anomaly in the planet/brown dwarf overlapping mass regime
The recent detection of the transit of very massive substellar companions
(CoRoT-3b, Deleuil et al. 2008; CoRoT-15b, Bouchy et al. 2010; WASP-30b,
Anderson et al. 2010; Hat-P-20b, Bakos et al. 2010) provides a strong
constraint to planet and brown dwarf formation and migration mechanisms.
Whether these objects are brown dwarfs originating from the gravitational
collapse of a dense molecular cloud that, at the same time, gave birth to the
more massive stellar companion, or whether they are planets that formed through
core accretion of solids in the protoplanetary disk can not always been
determined unambiguously and the mechanisms responsible for their short orbital
distances are not yet fully understood.
In this contribution, we examine the possibility to constrain the nature of a
massive substellar object from the various observables provided by the
combination of Radial Velocity and Photometry measurements (e.g. M_p, R_p, M_s,
Age, a, e...).
In a second part, developments in the modeling of tidal evolution at high
eccentricity and inclination - as measured for HD 80 606 with e=0.9337 (Naef et
al. 2001), XO-3 with a stellar obliquity >37.3+-3.7 deg (H\'ebrard et al. 2008;
Winn et al. 2009) and several other exoplanets - are discussed along with their
implication in the understanding of the radius anomaly problem of extrasolar
giant planets.Comment: Proceedings of the conference: "Detection and dynamics of transiting
exoplanets" held at the OHP, 23-27 August 2010. 7 pages, 3 figure
Financial spillovers from the US financial markets to the emerging markets during the subprime crisis: the example of Indian equity markets
This paper provides evidence of spillover effects from the Indian to the US financial markets. We use VAR and Kalman filter analysis to assess the influence of financial stress indicators like the LIBOR-OIS, CDS, the S&P 500 volatility and the exchange rate of the rupee against the Dollar on two indicators of financial stress in India, namely the illiquidity of stock indices and their volatility. We conduct an analysis bases on both daily and monthly frequency and use a database that consists of both aggregate and disaggregated indexes. Our results points to a signification contagion effect after the period following the Lehman Brothers collapse.Subprime crisis, Emerging Markets, VAR analysis, financial stress
Simple Priced Timed Games Are Not That Simple
Priced timed games are two-player zero-sum games played on priced timed
automata (whose locations and transitions are labeled by weights modeling the
costs of spending time in a state and executing an action, respectively). The
goals of the players are to minimise and maximise the cost to reach a target
location, respectively. We consider priced timed games with one clock and
arbitrary (positive and negative) weights and show that, for an important
subclass of theirs (the so-called simple priced timed games), one can compute,
in exponential time, the optimal values that the players can achieve, with
their associated optimal strategies. As side results, we also show that
one-clock priced timed games are determined and that we can use our result on
simple priced timed games to solve the more general class of so-called
reset-acyclic priced timed games (with arbitrary weights and one-clock)
Business Cycles Synchronization in East Asia: A Markov-Switching Approach
This paper attempts to analyze the relationships between the ASEAN-5 countries' business cycles. We examine the nature of business cycles correlation trying to disentangle between regional spillover effects (expansion and recession phases among the ASEAN-5 are correlated) and global spillovers where the business cycles of other countries (China, Japan and the US) play an important role in synchronizing the activity within the ASEAN-5. We employ a time-varying transition probability Markov switching framework in order to allow the degree of synchronization to fluctuate over time and across the phases of the business cycles. We provide evidence that the signals contained in some leading business cycles can impact the ASEAN-5 countries' individual business cycles
Efficient Energy Distribution in a Smart Grid using Multi-Player Games
Algorithms and models based on game theory have nowadays become prominent
techniques for the design of digital controllers for critical systems. Indeed,
such techniques enable automatic synthesis: given a model of the environment
and a property that the controller must enforce, those techniques automatically
produce a correct controller, when it exists. In the present paper, we consider
a class of concurrent, weighted, multi-player games that are well-suited to
model and study the interactions of several agents who are competing for some
measurable resources like energy. We prove that a subclass of those games
always admit a Nash equilibrium, i.e. a situation in which all players play in
such a way that they have no incentive to deviate. Moreover, the strategies
yielding those Nash equilibria have a special structure: when one of the agents
deviate from the equilibrium, all the others form a coalition that will enforce
a retaliation mechanism that punishes the deviant agent. We apply those results
to a real-life case study in which several smart houses that produce their own
energy with solar panels, and can share this energy among them in micro-grid,
must distribute the use of this energy along the day in order to avoid
consuming electricity that must be bought from the global grid. We demonstrate
that our theory allows one to synthesise an efficient controller for these
houses: using penalties to be paid in the utility bill as an incentive, we
force the houses to follow a pre-computed schedule that maximises the
proportion of the locally produced energy that is consumed.Comment: In Proceedings Cassting'16/SynCoP'16, arXiv:1608.0017
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