195,665 research outputs found
Pathologies of Neural Models Make Interpretations Difficult
One way to interpret neural model predictions is to highlight the most
important input features---for example, a heatmap visualization over the words
in an input sentence. In existing interpretation methods for NLP, a word's
importance is determined by either input perturbation---measuring the decrease
in model confidence when that word is removed---or by the gradient with respect
to that word. To understand the limitations of these methods, we use input
reduction, which iteratively removes the least important word from the input.
This exposes pathological behaviors of neural models: the remaining words
appear nonsensical to humans and are not the ones determined as important by
interpretation methods. As we confirm with human experiments, the reduced
examples lack information to support the prediction of any label, but models
still make the same predictions with high confidence. To explain these
counterintuitive results, we draw connections to adversarial examples and
confidence calibration: pathological behaviors reveal difficulties in
interpreting neural models trained with maximum likelihood. To mitigate their
deficiencies, we fine-tune the models by encouraging high entropy outputs on
reduced examples. Fine-tuned models become more interpretable under input
reduction without accuracy loss on regular examples.Comment: EMNLP 2018 camera read
Nonlinear theory of transverse beam echoes
Transverse beam echoes can be excited with a single dipole kick followed by a
single quadrupole kick. They have been used to measure diffusion in hadron
beams and have other diagnostic capabilities. Here we develop theories of the
transverse echo nonlinear in both the dipole and quadrupole kick strengths. The
theories predict the maximum echo amplitudes and the optimum strength
parameters. We find that the echo amplitude increases with smaller beam
emittance and the asymptotic echo amplitude can exceed half the initial dipole
kick amplitude. We show that multiple echoes can be observed provided the
dipole kick is large enough. The spectrum of the echo pulse can be used to
determine the nonlinear detuning parameter with small amplitude dipole kicks.
Simulations are performed to check the theoretical predictions. In the useful
ranges of dipole and quadrupole strengths, they are shown to be in reasonable
agreement.Comment: 32 pages, 11 figure
Enhanced Failure Detection Mechanism in MapReduce
The popularity of MapReduce programming model has increased interest in the research community for its improvement. Among the other directions, the point of fault tolerance, concretely the failure detection issue seems to be a crucial one, but that until now has not reached its satisfying level. Motivated by this, I decided to devote my main research during this period into having a prototype system architecture of MapReduce framework with a new failure detection service, containing both analytical (theoretical) and implementation part. I am confident that this work should lead the way for further contributions in detecting failures to any NoSQL App frameworks, and cloud storage systems in general
Voltage-tunable singlet-triplet transition in lateral quantum dots
Results of calculations and high source-drain transport measurements are
presented which demonstrate voltage-tunable entanglement of electron pairs in
lateral quantum dots. At a fixed magnetic field, the application of a
judiciously-chosen gate voltage alters the ground-state of an electron pair
from an entagled spin singlet to a spin triplet.Comment: 8.2 double-column pages, 10 eps figure
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