4,304 research outputs found
Deep Neural Networks for ECG-Based Pulse Detection during Out-of-Hospital Cardiac Arrest
The automatic detection of pulse during out-of-hospital cardiac arrest (OHCA) is necessary for the early recognition of the arrest and the detection of return of spontaneous circulation (end of the arrest). The only signal available in every single defibrillator and valid for the detection of pulse is the electrocardiogram (ECG). In this study we propose two deep neural network (DNN) architectures to detect pulse using short ECG segments (5 s), i.e., to classify the rhythm into pulseless electrical activity (PEA) or pulse-generating rhythm (PR). A total of 3914 5-s ECG segments, 2372 PR and 1542 PEA, were extracted from 279 OHCA episodes. Data were partitioned patient-wise into training (80%) and test (20%) sets. The first DNN architecture was a fully convolutional neural network, and the second architecture added a recurrent layer to learn temporal dependencies. Both DNN architectures were tuned using Bayesian optimization, and the results for the test set were compared to state-of-the art PR/PEA discrimination algorithms based on machine learning and hand crafted features. The PR/PEA classifiers were evaluated in terms of sensitivity (Se) for PR, specificity (Sp) for PEA, and the balanced accuracy (BAC), the average of Se and Sp. The Se/Sp/BAC of the DNN architectures were 94.1%/92.9%/93.5% for the first one, and 95.5%/91.6%/93.5% for the second one. Both architectures improved the performance of state of the art methods by more than 1.5 points in BAC.This work was supported by: The Spanish Ministerio de EconomÃa y Competitividad, TEC2015-64678-R,
jointly with the Fondo Europeo de Desarrollo Regional (FEDER), UPV/EHU via GIU17/031 and the Basque
Government through the grant PRE_2018_2_0260
Improving Generalization for Abstract Reasoning Tasks Using Disentangled Feature Representations
In this work we explore the generalization characteristics of unsupervised
representation learning by leveraging disentangled VAE's to learn a useful
latent space on a set of relational reasoning problems derived from Raven
Progressive Matrices. We show that the latent representations, learned by
unsupervised training using the right objective function, significantly
outperform the same architectures trained with purely supervised learning,
especially when it comes to generalization
Developmental Bayesian Optimization of Black-Box with Visual Similarity-Based Transfer Learning
We present a developmental framework based on a long-term memory and
reasoning mechanisms (Vision Similarity and Bayesian Optimisation). This
architecture allows a robot to optimize autonomously hyper-parameters that need
to be tuned from any action and/or vision module, treated as a black-box. The
learning can take advantage of past experiences (stored in the episodic and
procedural memories) in order to warm-start the exploration using a set of
hyper-parameters previously optimized from objects similar to the new unknown
one (stored in a semantic memory). As example, the system has been used to
optimized 9 continuous hyper-parameters of a professional software (Kamido)
both in simulation and with a real robot (industrial robotic arm Fanuc) with a
total of 13 different objects. The robot is able to find a good object-specific
optimization in 68 (simulation) or 40 (real) trials. In simulation, we
demonstrate the benefit of the transfer learning based on visual similarity, as
opposed to an amnesic learning (i.e. learning from scratch all the time).
Moreover, with the real robot, we show that the method consistently outperforms
the manual optimization from an expert with less than 2 hours of training time
to achieve more than 88% of success
Affective Facial Expression Processing via Simulation: A Probabilistic Model
Understanding the mental state of other people is an important skill for
intelligent agents and robots to operate within social environments. However,
the mental processes involved in `mind-reading' are complex. One explanation of
such processes is Simulation Theory - it is supported by a large body of
neuropsychological research. Yet, determining the best computational model or
theory to use in simulation-style emotion detection, is far from being
understood.
In this work, we use Simulation Theory and neuroscience findings on
Mirror-Neuron Systems as the basis for a novel computational model, as a way to
handle affective facial expressions. The model is based on a probabilistic
mapping of observations from multiple identities onto a single fixed identity
(`internal transcoding of external stimuli'), and then onto a latent space
(`phenomenological response'). Together with the proposed architecture we
present some promising preliminary resultsComment: Annual International Conference on Biologically Inspired Cognitive
Architectures - BICA 201
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