40 research outputs found
Traffic Light Control Using Deep Policy-Gradient and Value-Function Based Reinforcement Learning
Recent advances in combining deep neural network architectures with
reinforcement learning techniques have shown promising potential results in
solving complex control problems with high dimensional state and action spaces.
Inspired by these successes, in this paper, we build two kinds of reinforcement
learning algorithms: deep policy-gradient and value-function based agents which
can predict the best possible traffic signal for a traffic intersection. At
each time step, these adaptive traffic light control agents receive a snapshot
of the current state of a graphical traffic simulator and produce control
signals. The policy-gradient based agent maps its observation directly to the
control signal, however the value-function based agent first estimates values
for all legal control signals. The agent then selects the optimal control
action with the highest value. Our methods show promising results in a traffic
network simulated in the SUMO traffic simulator, without suffering from
instability issues during the training process
Single-modal and Multi-modal False Arrhythmia Alarm Reduction using Attention-based Convolutional and Recurrent Neural Networks
This study proposes a deep learning model that effectively suppresses the
false alarms in the intensive care units (ICUs) without ignoring the true
alarms using single- and multimodal biosignals. Most of the current work in the
literature are either rule-based methods, requiring prior knowledge of
arrhythmia analysis to build rules, or classical machine learning approaches,
depending on hand-engineered features. In this work, we apply convolutional
neural networks to automatically extract time-invariant features, an attention
mechanism to put more emphasis on the important regions of the input segmented
signal(s) that are more likely to contribute to an alarm, and long short-term
memory units to capture the temporal information presented in the signal
segments. We trained our method efficiently using a two-step training algorithm
(i.e., pre-training and fine-tuning the proposed network) on the dataset
provided by the PhysioNet computing in cardiology challenge 2015. The
evaluation results demonstrate that the proposed method obtains better results
compared to other existing algorithms for the false alarm reduction task in
ICUs. The proposed method achieves a sensitivity of 93.88% and a specificity of
92.05% for the alarm classification, considering three different signals. In
addition, our experiments for 5 separate alarm types leads significant results,
where we just consider a single-lead ECG (e.g., a sensitivity of 90.71%, a
specificity of 88.30%, an AUC of 89.51 for alarm type of Ventricular
Tachycardia arrhythmia
SleepEEGNet: Automated Sleep Stage Scoring with Sequence to Sequence Deep Learning Approach
Electroencephalogram (EEG) is a common base signal used to monitor brain
activity and diagnose sleep disorders. Manual sleep stage scoring is a
time-consuming task for sleep experts and is limited by inter-rater
reliability. In this paper, we propose an automatic sleep stage annotation
method called SleepEEGNet using a single-channel EEG signal. The SleepEEGNet is
composed of deep convolutional neural networks (CNNs) to extract time-invariant
features, frequency information, and a sequence to sequence model to capture
the complex and long short-term context dependencies between sleep epochs and
scores. In addition, to reduce the effect of the class imbalance problem
presented in the available sleep datasets, we applied novel loss functions to
have an equal misclassified error for each sleep stage while training the
network. We evaluated the proposed method on different single-EEG channels
(i.e., Fpz-Cz and Pz-Oz EEG channels) from the Physionet Sleep-EDF datasets
published in 2013 and 2018. The evaluation results demonstrate that the
proposed method achieved the best annotation performance compared to current
literature, with an overall accuracy of 84.26%, a macro F1-score of 79.66% and
Cohen's Kappa coefficient = 0.79. Our developed model is ready to test with
more sleep EEG signals and aid the sleep specialists to arrive at an accurate
diagnosis. The source code is available at
https://github.com/SajadMo/SleepEEGNet
The rate of using financial and non-financial indices in performance measurement of power distribution company in Markazi Province
According to conventional assessment indices of institutions or financial indices, balanced scorecard pays attention to non-financial indices which are mainly control and log indicators. In this direction, while having a close relationship between these two indices i.e. financial and non- financial indices, we are trying to verify organization objectives and strategies by applying all facilities and aptitudes of organization towards a main perspective. The function of different parts of organization is constantly evaluated by four perspectives of balanced scorecard including financial perspective, customer’s perspective, internal processes and developing and learning, and finally their development and improvement is tested