168 research outputs found
CORe50: a New Dataset and Benchmark for Continuous Object Recognition
Continuous/Lifelong learning of high-dimensional data streams is a
challenging research problem. In fact, fully retraining models each time new
data become available is infeasible, due to computational and storage issues,
while na\"ive incremental strategies have been shown to suffer from
catastrophic forgetting. In the context of real-world object recognition
applications (e.g., robotic vision), where continuous learning is crucial, very
few datasets and benchmarks are available to evaluate and compare emerging
techniques. In this work we propose a new dataset and benchmark CORe50,
specifically designed for continuous object recognition, and introduce baseline
approaches for different continuous learning scenarios
Semi-supervised Tuning from Temporal Coherence
Recent works demonstrated the usefulness of temporal coherence to regularize
supervised training or to learn invariant features with deep architectures. In
particular, enforcing smooth output changes while presenting temporally-closed
frames from video sequences, proved to be an effective strategy. In this paper
we prove the efficacy of temporal coherence for semi-supervised incremental
tuning. We show that a deep architecture, just mildly trained in a supervised
manner, can progressively improve its classification accuracy, if exposed to
video sequences of unlabeled data. The extent to which, in some cases, a
semi-supervised tuning allows to improve classification accuracy (approaching
the supervised one) is somewhat surprising. A number of control experiments
pointed out the fundamental role of temporal coherence.Comment: Under review as a conference paper at ICLR 201
Constraining the Higgs self couplings at colliders
We study the sensitivity to the shape of the Higgs potential of single,
double, and triple Higgs production at future colliders. Physics
beyond the Standard Model is parameterised through the inclusion of
higher-dimensional operators
with , which allows a consistent treatment of independent deviations of
the cubic and quartic self couplings beyond the tree level. We calculate the
effects induced by a modified potential up to one loop in single and double
Higgs production and at the tree level in triple Higgs production, for both
boson associated and boson fusion production mechanisms. We consider two
different scenarios. First, the dimension six operator provides the dominant
contribution (as expected, for instance, in a linear
effective-field-theory(EFT)); we find in this case that the corresponding
Wilson coefficient can be determined at accuracy by just
combining accurate measurements of single Higgs cross sections at 240-250 GeV and double Higgs production in boson fusion at higher
energies. Second, both operators of dimension six and eight can give effects of
similar order, i.e., independent quartic self coupling deviations are present.
Constraints on Wilson coefficients can be best tested by combining measurements
from single, double and triple Higgs production. Given that the sensitivity of
single Higgs production to the dimension eight operator is presently unknown,
we consider double and triple Higgs production and show that combining their
information colliders at higher energies will provide first coarse constraints
on the corresponding Wilson coefficient.Comment: minor changes, version accepted for publication in JHE
Associated production of a top-quark pair with vector bosons at NLO in QCD: impact on searches at the LHC
We study the production of a top-quark pair in association with one and two
vector bosons, and with , at the
LHC. We provide predictions at next-to-leading order in QCD for total cross
sections and top-quark charge asymmetries as well as for differential
distributions. A thorough discussion of the residual theoretical uncertainties
related to missing higher orders and to parton distribution functions is
presented. As an application, we calculate the total cross sections for this
class of processes (together with and
production) at hadron colliders for energies up to 100 TeV. In addition, by
matching the NLO calculation to a parton shower, we determine the contribution
of and to final state signatures (two-photon and
two-same-sign-, three- and four-lepton) relevant for analyses at
the Run II of the LHC.Comment: 44 pages, 23 figures. Version published on JHEP, typos in Table 5
have been correcte
Continual Reinforcement Learning in 3D Non-stationary Environments
High-dimensional always-changing environments constitute a hard challenge for
current reinforcement learning techniques. Artificial agents, nowadays, are
often trained off-line in very static and controlled conditions in simulation
such that training observations can be thought as sampled i.i.d. from the
entire observations space. However, in real world settings, the environment is
often non-stationary and subject to unpredictable, frequent changes. In this
paper we propose and openly release CRLMaze, a new benchmark for learning
continually through reinforcement in a complex 3D non-stationary task based on
ViZDoom and subject to several environmental changes. Then, we introduce an
end-to-end model-free continual reinforcement learning strategy showing
competitive results with respect to four different baselines and not requiring
any access to additional supervised signals, previously encountered
environmental conditions or observations.Comment: Accepted in the CLVision Workshop at CVPR2020: 13 pages, 4 figures, 5
table
Trilinear Higgs coupling determination via single-Higgs differential measurements at the LHC
We study one-loop effects induced by an anomalous Higgs trilinear coupling on
total and differential rates for the decay and some of the main
single-Higgs production channels at the LHC, namely, VBF, , and
. Our results are based on a public code that calculates these effects by
simply reweighting samples of Standard-Model-like events for a given production
channel. For and production, where differential effects are
particularly relevant, we include Standard Model electroweak corrections, which
have similar sizes but different kinematic dependences. Finally, we study the
sensitivity of future LHC runs to determine the trilinear coupling via
inclusive and differential measurements, considering also the case where the
Higgs couplings to vector bosons and the top quark is affected by new physics.
We find that the constraints on the couplings and the relevance of differential
distributions critically depend on the expected experimental and theoretical
uncertainties.Comment: 31 pages, 15 figures, 5 tables; Matches the journal versio
Probing the Higgs self coupling via single Higgs production at the LHC
We propose a method to determine the trilinear Higgs self coupling that is
alternative to the direct measurement of Higgs pair production total cross
sections and differential distributions. The method relies on the effects that
electroweak loops featuring an anomalous trilinear coupling would imprint on
single Higgs production at the LHC. We first calculate these contributions to
all the phenomenologically relevant Higgs production (, VBF, ,
, ) and decay (, , ,
) modes at the LHC and then estimate the sensitivity to the
trilinear coupling via a one-parameter fit to the single Higgs measurements at
the LHC 8 TeV. We find that the bounds on the self coupling are already
competitive with those from Higgs pair production and will be further improved
in the current and next LHC runs.Comment: 34 pages, 13 figures, 5 tables; V2: New appendix A added on the
comparison with the Effective Field Theory approach; V3: Journal versio
Towards Artifacts-free Image Defogging
In this paper we present a novel defogging technique,named CurL-Defog, aimed at minimizing the creation of unwanted artifacts during the defogging process. The majority of learning based defogging approaches rely on paired data (i.e.,the same images with and without fog), where fog is artificially added to clear images: this often provides good results on mildly fogged images but does not generalize well to real difficult cases. On the other hand, the models trained with real unpaired data (e.g. CycleGAN) can provide visually impressive results but they often produce unwanted artifacts. In this paper we propose a curriculum learning strategy coupled with an enhanced CycleGAN model in order to reduce the number of produced artifacts, while maintaining state-of-the-art performance in terms of contrast enhancement and image reconstruction. We also introduce a new metric, called HArD (Hazy Artifact Detector) to numerically quantify the amount of artifacts in the defogged images, thus avoiding the tedious and subjective manual inspection of the results. The proposed approach compares favorably with state-of-the-art techniques on both real and synthetic datasets
Arithmetic with Language Models: from Memorization to Computation
A better understanding of the emergent computation and problem-solving
capabilities of recent large language models is of paramount importance to
further improve them and broaden their applicability. This work investigates
how a language model, trained to predict the next token, can perform arithmetic
computations generalizing beyond training data. Binary addition and
multiplication constitute a good testbed for this purpose, since they require a
very small vocabulary and exhibit relevant input/output discontinuities making
smooth input interpolation ineffective for novel data. We successfully trained
a light language model to learn these tasks and ran a number of experiments to
investigate the extrapolation capabilities and internal information processing.
Our findings support the hypotheses that the language model works as an
Encoding-Regression-Decoding machine where the computation takes place in the
value space once the input token representation is mapped to an appropriate
internal representation
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