6,618 research outputs found
The model of an anomaly detector for HiLumi LHC magnets based on Recurrent Neural Networks and adaptive quantization
This paper focuses on an examination of an applicability of Recurrent Neural
Network models for detecting anomalous behavior of the CERN superconducting
magnets. In order to conduct the experiments, the authors designed and
implemented an adaptive signal quantization algorithm and a custom GRU-based
detector and developed a method for the detector parameters selection. Three
different datasets were used for testing the detector. Two artificially
generated datasets were used to assess the raw performance of the system
whereas the 231 MB dataset composed of the signals acquired from HiLumi magnets
was intended for real-life experiments and model training. Several different
setups of the developed anomaly detection system were evaluated and compared
with state-of-the-art OC-SVM reference model operating on the same data. The
OC-SVM model was equipped with a rich set of feature extractors accounting for
a range of the input signal properties. It was determined in the course of the
experiments that the detector, along with its supporting design methodology,
reaches F1 equal or very close to 1 for almost all test sets. Due to the
profile of the data, the best_length setup of the detector turned out to
perform the best among all five tested configuration schemes of the detection
system. The quantization parameters have the biggest impact on the overall
performance of the detector with the best values of input/output grid equal to
16 and 8, respectively. The proposed solution of the detection significantly
outperformed OC-SVM-based detector in most of the cases, with much more stable
performance across all the datasets.Comment: Related to arXiv:1702.0083
Using LSTM recurrent neural networks for monitoring the LHC superconducting magnets
The superconducting LHC magnets are coupled with an electronic monitoring
system which records and analyses voltage time series reflecting their
performance. A currently used system is based on a range of preprogrammed
triggers which launches protection procedures when a misbehavior of the magnets
is detected. All the procedures used in the protection equipment were designed
and implemented according to known working scenarios of the system and are
updated and monitored by human operators.
This paper proposes a novel approach to monitoring and fault protection of
the Large Hadron Collider (LHC) superconducting magnets which employs
state-of-the-art Deep Learning algorithms. Consequently, the authors of the
paper decided to examine the performance of LSTM recurrent neural networks for
modeling of voltage time series of the magnets. In order to address this
challenging task different network architectures and hyper-parameters were used
to achieve the best possible performance of the solution. The regression
results were measured in terms of RMSE for different number of future steps and
history length taken into account for the prediction. The best result of
RMSE=0.00104 was obtained for a network of 128 LSTM cells within the internal
layer and 16 steps history buffer
Quantized Non-Volatile Nanomagnetic Synapse based Autoencoder for Efficient Unsupervised Network Anomaly Detection
In the autoencoder based anomaly detection paradigm, implementing the
autoencoder in edge devices capable of learning in real-time is exceedingly
challenging due to limited hardware, energy, and computational resources. We
show that these limitations can be addressed by designing an autoencoder with
low-resolution non-volatile memory-based synapses and employing an effective
quantized neural network learning algorithm. We propose a ferromagnetic
racetrack with engineered notches hosting a magnetic domain wall (DW) as the
autoencoder synapses, where limited state (5-state) synaptic weights are
manipulated by spin orbit torque (SOT) current pulses. The performance of
anomaly detection of the proposed autoencoder model is evaluated on the NSL-KDD
dataset. Limited resolution and DW device stochasticity aware training of the
autoencoder is performed, which yields comparable anomaly detection performance
to the autoencoder having floating-point precision weights. While the limited
number of quantized states and the inherent stochastic nature of DW synaptic
weights in nanoscale devices are known to negatively impact the performance,
our hardware-aware training algorithm is shown to leverage these imperfect
device characteristics to generate an improvement in anomaly detection accuracy
(90.98%) compared to accuracy obtained with floating-point trained weights.
Furthermore, our DW-based approach demonstrates a remarkable reduction of at
least three orders of magnitude in weight updates during training compared to
the floating-point approach, implying substantial energy savings for our
method. This work could stimulate the development of extremely energy efficient
non-volatile multi-state synapse-based processors that can perform real-time
training and inference on the edge with unsupervised data
Unsupervised mapping of phase diagrams of 2D systems from infinite projected entangled-pair states via deep anomaly detection
We demonstrate how to map out the phase diagram of a two dimensional quantum
many body system with no prior physical knowledge by applying deep
\textit{anomaly detection} to ground states from infinite projected entangled
pair state simulations. As a benchmark, the phase diagram of the 2D frustrated
bilayer Heisenberg model is analyzed, which exhibits a second-order and two
first-order quantum phase transitions. We show that in order to get a good
qualitative picture of the transition lines, it suffices to use data from the
cost-efficient simple update optimization. Results are further improved by
post-selecting ground-states based on their energy at the cost of contracting
the tensor network once. Moreover, we show that the mantra of ``more training
data leads to better results'' is not true for the learning task at hand and
that, in principle, one training example suffices for this learning task. This
puts the necessity of neural network optimizations for these learning tasks in
question and we show that, at least for the model and data at hand, a simple
geometric analysis suffices.Comment: Submission to SciPost; code and data available at
https://github.com/Qottmann/anomaly-detection-PEP
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