6,305 research outputs found
Post-market infrastructures and financial stability.
Post-market infrastructures execute critical functions — clearing and delivery versus payment — for the performance of trades in financial assets. This makes them potential vectors for destabilisation of the financial system in the event of malfunctions. Their impact on systemic risk warrants the supervisory and oversight authorities' concern for analysing the various risks that such infrastructures may incur and the efforts to establish a comprehensive set of recommendations for mitigating these risks. This objective has now been achieved with the publication of the CPSS/IOSCO recommendations in November 2001. These recommendations are intended to be universal in scope. In addition to setting adequate standards, the relevant authorities, and central banks in particular, have extended the scope of their responsibility in the field of maintaining financial stability by including the oversight of post-market infrastructures. The statutes of the Banque de France have recently been amended in such terms. Securities clearing and settlement infrastructures are changing rapidly both in Europe, where consolidation and sweeping rationalisation are taking place, and on the wider international scene. Users expect greater functional integration of infrastructures, which should contribute to the expansion of low-cost cross-border transactions and greater efficiency in securities processing. These changes have prompted the relevant authorities to co-operate more closely in the regulation, prudential supervision and oversight of the cross-border infrastructures being developed in Europe. With the development of pan-European infrastructures in the Paris financial markets, the Banque de France has played a very active role in enhancing co-ordinated oversight in conjunction with the other relevant national authorities.
Physical Representation-based Predicate Optimization for a Visual Analytics Database
Querying the content of images, video, and other non-textual data sources
requires expensive content extraction methods. Modern extraction techniques are
based on deep convolutional neural networks (CNNs) and can classify objects
within images with astounding accuracy. Unfortunately, these methods are slow:
processing a single image can take about 10 milliseconds on modern GPU-based
hardware. As massive video libraries become ubiquitous, running a content-based
query over millions of video frames is prohibitive.
One promising approach to reduce the runtime cost of queries of visual
content is to use a hierarchical model, such as a cascade, where simple cases
are handled by an inexpensive classifier. Prior work has sought to design
cascades that optimize the computational cost of inference by, for example,
using smaller CNNs. However, we observe that there are critical factors besides
the inference time that dramatically impact the overall query time. Notably, by
treating the physical representation of the input image as part of our query
optimization---that is, by including image transforms, such as resolution
scaling or color-depth reduction, within the cascade---we can optimize data
handling costs and enable drastically more efficient classifier cascades.
In this paper, we propose Tahoma, which generates and evaluates many
potential classifier cascades that jointly optimize the CNN architecture and
input data representation. Our experiments on a subset of ImageNet show that
Tahoma's input transformations speed up cascades by up to 35 times. We also
find up to a 98x speedup over the ResNet50 classifier with no loss in accuracy,
and a 280x speedup if some accuracy is sacrificed.Comment: Camera-ready version of the paper submitted to ICDE 2019, In
Proceedings of the 35th IEEE International Conference on Data Engineering
(ICDE 2019
Localized systems coupled to small baths: from A to Z
We investigate what happens if an Anderson localized system is coupled to a
small bath, with a discrete spectrum, when the coupling between system and bath
is specially chosen so as to never localize the bath. We find that the effect
of the bath on localization in the system is a non-monotonic function of the
coupling between system and bath. At weak couplings, the bath facilitates
transport by allowing the system to 'borrow' energy from the bath. But above a
certain coupling the bath produces localization, because of an orthogonality
catastrophe, whereby the bath 'dresses' the system and hence suppresses the
hopping matrix element. We call this last regime the regime of
"Zeno-localization", since the physics of this regime is akin to the quantum
Zeno effect, where frequent measurements of the position of a particle impede
its motion. We confirm our results by numerical exact diagonalization
Analysing the behaviour of robot teams through relational sequential pattern mining
This report outlines the use of a relational representation in a Multi-Agent
domain to model the behaviour of the whole system. A desired property in this
systems is the ability of the team members to work together to achieve a common
goal in a cooperative manner. The aim is to define a systematic method to
verify the effective collaboration among the members of a team and comparing
the different multi-agent behaviours. Using external observations of a
Multi-Agent System to analyse, model, recognize agent behaviour could be very
useful to direct team actions. In particular, this report focuses on the
challenge of autonomous unsupervised sequential learning of the team's
behaviour from observations. Our approach allows to learn a symbolic sequence
(a relational representation) to translate raw multi-agent, multi-variate
observations of a dynamic, complex environment, into a set of sequential
behaviours that are characteristic of the team in question, represented by a
set of sequences expressed in first-order logic atoms. We propose to use a
relational learning algorithm to mine meaningful frequent patterns among the
relational sequences to characterise team behaviours. We compared the
performance of two teams in the RoboCup four-legged league environment, that
have a very different approach to the game. One uses a Case Based Reasoning
approach, the other uses a pure reactive behaviour.Comment: 25 page
β-decay half-lives and β-delayed neutron emission probabilities for several isotopes of Au, Hg, Tl, Pb, and Bi, beyond N = 126
Background: There have been measurements on roughly 230 nuclei that are β-delayed neutron emitters. They
range from 8
He up to 150La. Apart from 210Tl, with a branching ratio of only 0.007%, no other neutron emitter
has been measured beyond A = 150. Therefore, new data are needed, particularly in the region of heavy nuclei
around N = 126, in order to guide theoretical models and help understand the formation of the third r-process
peak at A ∼ 195.
Purpose: To measure both β-decay half-lives and neutron branching ratios of several neutron-rich Au, Hg, Tl,
Pb, and Bi isotopes beyond N = 126.
Method: Ions of interest were produced by fragmentation of a 238U beam, selected and identified via the GSI-FRS
fragment separator. A stack of segmented silicon detectors (SIMBA) was used to measure ion implants and β
decays. An array of 30 3
He tubes embedded in a polyethylene matrix (BELEN) was used to detect neutrons with
high efficiency and selectivity. A self-triggered digital system is employed to acquire data and to enable time
correlations. The latter were analyzed with an analytical model and results for the half-lives and neutron-branching
ratios were derived by using the binned maximum-likelihood method.
Results: Twenty new β-decay half-lives are reported for 204−206Au, 208–211Hg,
211–216Tl,
215–218Pb, and 218–220Bi,
nine of them for the first time. Neutron emission probabilities are reported for 210,211Hg and 211–216Tl.
Conclusions: The new β-decay half-lives are in good agreement with previous measurements on nuclei in this
region. The measured neutron emission probabilities are comparable to or smaller than values predicted by global
models such as relativistic Hartree Bogoliubov plus the relativistic quasi-particle random phase approximation
(RHB + RQRPA).Spanish Ministerio de EconomÃa y Competitividad-FPA2011- 28770-C03-03, FPA2008-04972-C03-3, AIC-D2011-0705, FPA2011-24553, FPA2008-6419, FPA2010-17142, FPA2014-52823-C2-1-P, FPA2014- 52823-C2-2-P, and CPAN CSD-2007-00042 (Ingenio2010)Program Severo Ochoa-SEV-2014-0398German Helmholtz Association (Young Investigators)-VH-NG 627 (LISA-Lifetime Spectroscopy for Astrophysics)Nuclear Astrophysics Virtual Institute-VH-VI-417German Bundesministerium für Bildung und Forschung-06MT7178 / 05P12WOFNFSpanish Nuclear Security Council (CSN)-Catedra ArgosUK Science & Technology Facilities Council (STFC)-ST/F012012/
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