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  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Semi-mind controlled robots based on Reinforcement Learning for Indoor Application</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Ilyes Naidji</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Ahmed Tibermacine</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Walid Guettala</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Imad Eddine Tibermacine</string-name>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Department of Computer Science, University Mohamed Khider of Biskra</institution>
          ,
          <country country="DZ">Algeria</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>Department of Computer, Control and Management Engineering , Sapienza University of Rome</institution>
          ,
          <country country="IT">Italy</country>
        </aff>
      </contrib-group>
      <fpage>51</fpage>
      <lpage>59</lpage>
      <abstract>
        <p>This paper presents a solution to this challenge by introducing interactive feedback derived from brain signals to train robots using deep reinforcement learning, particularly in the context of indoor maze navigation. Our objective is to enhance the learning process in a human-robot interaction scenario by incorporating human emotion or attention feedback. To accomplish this, we empowered the robot to learn new tasks through a dynamic policy network based on human feedback, and we augmented this input with other sensor data, including LIDAR. Various experiments are conducted to compare the eficacy of manual feedback, brain signal feedback, and no brain signal feedback, employing diverse Reinforcement Learning models. Additionally, we explore diferent models for emotion classification, employing Graph Neural Network models and traditional deep learning models, and subsequently compare the outcomes.</p>
      </abstract>
      <kwd-group>
        <kwd>eol&gt;EEG</kwd>
        <kwd>Deep Learning</kwd>
        <kwd>Graph Neural Networks</kwd>
        <kwd>Human-Robot Interaction</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1. Introduction</title>
      <sec id="sec-1-1">
        <title>IV dataset, and 88.51% and 85.62% for four classifications</title>
        <p>and two dichotomies on the DEAP dataset, respectively.</p>
        <p>
          Robotic applications have become indispensable across The key contributions of the paper encompass the
introdiverse fields such as rescue operations, medical assis- duction of the CAN model, which combines deep-gated
tance, and autonomous driving. Within the realm of recurrent neural networks [
          <xref ref-type="bibr" rid="ref10">10</xref>
          ] with canonical
correlamobile robotics, autonomous navigation stands out as tion and an attention mechanism [
          <xref ref-type="bibr" rid="ref11">11</xref>
          ], and the
exploa crucial research focus [
          <xref ref-type="bibr" rid="ref1 ref2">1, 2</xref>
          ], traditionally relying on ration of coordinated representation in tasks related to
map-building techniques like SLAM [
          <xref ref-type="bibr" rid="ref3">3</xref>
          ]. Nevertheless, multimodal emotion recognition[
          <xref ref-type="bibr" rid="ref12">12</xref>
          ].
there is a growing interest in mapless navigation, which The literature reviewed diverse approaches
establishes a direct link between sensory inputs and robot to autonomous robot navigation in unfamiliar
actions. While deep reinforcement learning (DRL) has environments[
          <xref ref-type="bibr" rid="ref13 ref14 ref15">13, 14, 15</xref>
          ]. Simultaneous Localization
made noteworthy advancements in autonomous naviga- and Mapping (SLAM) algorithms, such as the one
tion, the challenges of real-world training persist [
          <xref ref-type="bibr" rid="ref4 ref5">4, 5</xref>
          ]. proposed in [
          <xref ref-type="bibr" rid="ref16">16</xref>
          ] and the lightweight OrthoSLAM
        </p>
        <p>
          In the presented paper [
          <xref ref-type="bibr" rid="ref6">6</xref>
          ], the authors introduce a algorithm [
          <xref ref-type="bibr" rid="ref17">17</xref>
          ], emphasize the simultaneous mapping
novel model named the Correlated Attention Network and localization process. In [
          <xref ref-type="bibr" rid="ref18">18</xref>
          ], an innovative method
(CAN) for multimodal emotion recognition[
          <xref ref-type="bibr" rid="ref7 ref8">7, 8</xref>
          ]. This is introduced, combining Hector SLAM with an Artificial
model extends the attention-based recurrent neural net- Potential Field (APF) controller, specifically designed
work by integrating correlation calculations of difer- for indoor navigation in GPS-denied environments.
ent gated recurrent units, specifically targeting the cor- The proposal in [
          <xref ref-type="bibr" rid="ref19">19</xref>
          ] advocates for a semantically rich
relation between EEG and eye movement signals[
          <xref ref-type="bibr" rid="ref9">9</xref>
          ]. graph representation in the context of indoor navigation.
Through the utilization of coordinated representation Additionally, research in [
          <xref ref-type="bibr" rid="ref20 ref21">20, 21</xref>
          ] explores end-to-end
incorporating complementary features, the CAN model approaches utilizing Convolutional Neural Networks
aims to achieve enhanced emotion classification accu- (CNNs) for autonomous robot navigation, particularly
racy. The experimental outcomes on three real-world with RGB-D cameras[
          <xref ref-type="bibr" rid="ref22">22</xref>
          ].
datasets reveal that the proposed model outperforms ex- Methods based on Deep Reinforcement Learning (DRL)
isting state-of-the-art methods, achieving mean accura- are also explored, such as the fusion of deep
reincies of 94.03% on the SEED dataset, 87.71% on the SEED forcement learning with Recurrent Neural Networks
(RNNs)[23, 24? ] for path selection discussed in [
          <xref ref-type="bibr" rid="ref25">25</xref>
          ]. In
ICYRIME 2023: 8th International Conference of Yearly Reports on [
          <xref ref-type="bibr" rid="ref26">26</xref>
          ], an approach utilizing Deep Q-Network (DQN) for
Informatics, Mathematics, and Engineering. Naples, July 28-31, 2023 autonomous robot navigation with visual observations is
$ ilyes.naidji@univ-biskra.dz (I. Naidji); presented, albeit relying on RGB-D cameras. Addressing
wahamlidegdu.teibttearlma@acginmea@il.ucnoimv-(bWis.kGrau.deztt(aAla.);Tibermacine); collision avoidance and navigation, [
          <xref ref-type="bibr" rid="ref27 ref28">27, 28</xref>
          ] employ a
tibermacine@diag.uniroma1.it (I. E. Tibermacine) Double Deep Q-Network (DDQN) approach. Lastly, [
          <xref ref-type="bibr" rid="ref29">29</xref>
          ]
© 2023 Copyright for this paper by its authors. Use permitted under Creative Commons License introduces an Asynchronous Advantage Actor-Critic
netAttribution 4.0 International (CC BY 4.0).
The overarching design of this global system [Fig.1]
adopts an AI perspective and consists of two principal
components: the Brain Signal segment utilizing EEG and
the DRL (Deep Reinforcement Learning) segment. The
system architecture is defined by an environment
featuring a maze with static obstacles representing maze walls
and dynamic obstacles. A robot, guided by a DRL agent,
endeavors to navigate through the maze with the goal of
reaching a randomly generated red circular spot.
        </p>
        <p>The DRL agent is reliant on two primary feedback
signals for observations. The first is the EEG signal,
portraying emotions like sadness, happiness, and neutrality.</p>
        <p>The second feedback is derived from a 2D LIDAR sensor,
work to enhance generalization and reduce learning time furnishing environmental information to the agent.
Hufor indoor robot navigation. man interaction with the system is facilitated through</p>
        <p>These studies ofer valuable insights into various tech- a Brain-Computer Interface (BCI) setup. Users observe
niques and algorithms employed in autonomous robot the simulation and gather EEG recordings. The collected
navigation, contributing to the comprehension of Simul- EEG data undergoes preprocessing, feature extraction,
taneous Localization and Mapping (SLAM), end-to-end and model prediction to categorize emotional states into
strategies, Deep Reinforcement Learning (DRL), and col- three classes: sad, happy, and neutral.
lision avoidance methodologies. Concurrently, the 2D LIDAR sensor data is
amalgamated with the EEG data and serves as observations for
the DRL agent. The agent acquires the ability to make
2. Proposed model optimal decisions and execute actions by assimilating
the combined feedback, facilitating efective navigation
2.1. Global System Design through the maze. Various iterations of the system have
been created, incorporating versions that exclusively rely
on the 2D LIDAR sensor or concentrate solely on emotion
feedback. Additionally, diverse noise types and persistent
feedback mechanisms have been investigated to improve
the overall performance of the system.</p>
        <p>In the upcoming sections, specific Deep Reinforcement
Learning (DRL) algorithms and their intricate
functionalities will be elucidated, ofering deeper insights into the
operational and learning processes of the system.</p>
      </sec>
    </sec>
    <sec id="sec-2">
      <title>3. EEG DATASET</title>
      <p>3.1. Dataset Overview Concerning the brain signal feedback, it can be
substituted with keyboard input involving humans as the
The EEG dataset comprises recordings from 15 partici- source of feedback. In this scenario, users can input
pants involved in the experiment. Each participant un- their emotional state, specifying whether they feel happy,
derwent three sessions on distinct days, and each session sad, or neutral. Alternatively, the brain signal feedback
encompassed 24 trials. The film clips displayed during system can be replaced with generated samples of
emothese trials were meticulously selected to elicit emotions tional states adhering to a uniform distribution. In this
such as happiness, sadness, fear, or a neutral emotional approach, three variables govern the probability of each
state. Consequently, the dataset encompasses four emo- emotional event: happiness, sadness, and neutrality.
tional classes: happiness, sadness, fear, and neutrality.</p>
      <p>
        The SEED IV dataset [
        <xref ref-type="bibr" rid="ref30">30</xref>
        ] ofers an extensive compila- 3.2.4. Classification Models Used For Emotion
tion of EEG signals, with a specific emphasis on emotion Dataset
recognition utilizing both EEG and eye movement data.
      </p>
      <p>This section provides an outline of the EEG segment We employed emotion classification as both a feedback
within the SEED IV dataset utilized in this thesis. It en- system and an observation for deep reinforcement
learncompasses details regarding the number of subjects, the ing. This feedback ofers insights into the individual’s
iflm clips utilized, and the classes available. Additionally, emotional state within the simulation. To accomplish this,
information about the preprocessing of the EEG signals we utilized diverse models for classifying brain signals
and the process of feature extraction is presented. into four categories: angry, sad, happy, or neutral.</p>
      <sec id="sec-2-1">
        <title>3.2.3. Replacmnet of Emotion feedback</title>
        <p>3.2. Brain Signal Feedback Part</p>
        <sec id="sec-2-1-1">
          <title>This is a sub-system design from the global system which has 2 phases:</title>
          <p>3.2.1. Phase 1
During this stage, the model, specifically the CNN model,
is trained utilizing the SEED-IV dataset. We implemented
the preprocessing and feature extraction methods
outlined in the dataset section. For our model, predictions
were made for four distinct classes. However, within
our overarching system design, the classes of sadness
and fear were amalgamated into a single class.
Subsequently, the batches were converted into 2D images to
be inputted into the CNN model. Alongside the CNN
model trained in the train data loader, we also conducted
experiments with alternative models, including advanced
CNN architecture, LSTM, and ViT.
3.2.2. Phase 2</p>
        </sec>
        <sec id="sec-2-1-2">
          <title>Upon completing the initial phase, we employ the trained</title>
          <p>weights and integrate them into our system as an ofline
model. This ofline model encompasses a predetermined
function that receives input from the BCI API, initially
transforming the features to predict real-time human
emotions. The predicted emotions are then stored in the
EEG bufer. Subsequently, the EEG bufer is combined
with the 2D lidar bufer, creating the sensor bufer and
constituting the resultant batch.</p>
        </sec>
      </sec>
      <sec id="sec-2-2">
        <title>3.2.5. Reward Function</title>
        <sec id="sec-2-2-1">
          <title>The reward function comprises five versions denoted as</title>
          <p>A, B, C, D, and E. In Version A, lidar serves as the
observation, while Version B utilizes a uniform distribution of
emotion. Version C combines the uniform distribution of
emotion with lidar, Version D relies solely on emotion,
and Version E combines emotion with lidar. Our focus
will be on the two principal reward functions, with the
other three representing variations of these main ones.</p>
          <p>The first reward function is a hybrid model that
incorporates lidar and emotion as observations. The second
reward function relies on a uniform distribution of
emotion based on a specified probability. Additionally, there
is a variable named ’constant’ that is added to the reward
when the robot successfully avoids collisions with
obstacles. This constant value varies based on four types:
Step-1, Step-2, Episode, and time, each defined in
seconds. The constant is added according to one of these
four types.</p>
        </sec>
      </sec>
    </sec>
    <sec id="sec-3">
      <title>4. EXPERIMENTAL SETUP</title>
      <p>4.1. Preprocessing and Feature Extraction</p>
      <sec id="sec-3-1">
        <title>During the EEG preprocessing phase, several procedures</title>
        <p>were implemented to ready the data for subsequent
analysis. These steps encompass downsampling the raw EEG
data to a sampling rate of 200 Hz and applying a
bandpass filter ranging from 1 Hz to 75 Hz to eliminate noise.
Subsequent to the preprocessing stage, EEG feature
extraction was conducted to capture pertinent information
from the data. Extracted features include Power
Spectral Density (PSD) and Diferential Entropy (DE). PSD</p>
      </sec>
    </sec>
    <sec id="sec-4">
      <title>6. Results</title>
      <p>6.1. Simulation Challenges in Maze
Environment
quantifies the power distribution across five frequency
bands, specifically Delta (1 Hz - 4 Hz), Theta (4 Hz - 8
Hz), Alpha (8 Hz - 14 Hz), Beta (14 Hz - 31 Hz), and
Gamma (31 Hz - 50 Hz). Conversely, DE computes the
diferential entropy within each segment and across the
aforementioned frequency bands.</p>
      <sec id="sec-4-1">
        <title>In this section, we delve into the diverse simulation chal</title>
        <p>lenges encountered within the maze environment. These
4.1.1. Utilization of EEG Feature Data challenges are intentionally designed to assess the robot’s
capabilities and performance across various scenarios.</p>
        <p>The  ℎ directory within the SEED IV An illustration showcasing the nine distinct challenges
dataset served as the source for feature extraction, specif- can be found in Figure.2.
ically employing the PSD and DE features. Data from
each .mat file was loaded and transformed into a format 6.2. Challenge 1: Square Maze
suitable for model training. To optimize the training
process, samples from each .mat file were concatenated into The first challenge introduces a straightforward square
batches of size 128, where each batch contained EEG maze with the robot positioned at the center. This
chalsegments from diferent trials of the same subject. Fur- lenge serves as the baseline for assessing the robot’s
thermore, one label from the four emotional classes was navigation capabilities.
assigned to each batch. These batches were then used to
construct a dataloader, which was subsequently divided 6.3. Challenge 2: Square Maze with
into training, validation, and testing sets with ratios of
0.8, 0.1, and 0.1, respectively. To introduce randomness Dynamic Obstacles
into the training process, the dataset was shufled.</p>
        <p>By employing this methodology, our objective is to
train a model capable of recognizing emotions based on
EEG features extracted from the SEED IV dataset.</p>
      </sec>
      <sec id="sec-4-2">
        <title>Challenge 2 expands on the preceding challenge by in</title>
        <p>corporating four dynamic obstacles into the square maze.
The introduction of these obstacles enhances the
complexity of the robot’s path planning and obstacle
avoidance strategies.</p>
        <sec id="sec-4-2-1">
          <title>4.1.2. Simulation Feedback Data</title>
        </sec>
      </sec>
      <sec id="sec-4-3">
        <title>The dataset utilized in this case study comprises environ</title>
        <p>mental data acquired from a LIDAR sensor and feedback
from an EEG (electroencephalogram) device. The LIDAR
sensor supplies information about the surroundings,
including distances to obstacles and the robot’s orientation.
Concurrently, the EEG device gauges the brain activity of
the operator, ofering feedback on their cognitive state.</p>
      </sec>
    </sec>
    <sec id="sec-5">
      <title>5. Dynamical Graph Convolutional</title>
    </sec>
    <sec id="sec-6">
      <title>Neural Networks (DGCNN)</title>
      <p>6.4. Challenge 3: Varied Speed and</p>
      <p>Movement of Dynamic Obstacles</p>
      <sec id="sec-6-1">
        <title>In this particular challenge, the dynamic obstacles showcase varying speeds and movement patterns in contrast to Challenge 2. The robot is required to adjust its navigation strategy accordingly to evade collisions.</title>
        <p>6.5. Challenge 4: Maze with Inner Walls
and Two Dynamic Obstacles</p>
      </sec>
      <sec id="sec-6-2">
        <title>Challenge 4 integrates inner walls into the maze structure</title>
        <p>The DGCNN (Dynamical Graph Convolutional Neural and introduces two dynamic obstacles. The inclusion of
Networks) model [? ] is designed for EEG emotion recog- inner walls adds an additional layer of complexity to the
nition tasks. It leverages graph convolutional operations robot’s path planning process.
to capture spatial dependencies between diferent
electrodes in EEG signals. Graph Neural Networks, such 6.6. Challenge 5: Maze with Inner Walls
as the DGCNN model, are essential for capturing and and Six Dynamic Obstacles
modeling relationships between graph-structured data,
where nodes represent entities and edges represent con- This particular challenge incorporates inner walls;
hownections. In the con- text of EEG emotion recognition, ever, it introduces a higher number of dynamic obstacles,
GNNs enable the DGCNN model to efectively learn and totaling six. This challenge is designed to assess the
exploit the spatial dependencies between diferent elec- robot’s capability to navigate through an environment
trodes. By leveraging graph convolutional operations, with an increased density of obstacles.
the DGCNN model can capture complex patterns and
representations from EEG signals, leading to improved
emotion recognition performance.
6.7. Challenge 6: Maze with Dynamic</p>
        <p>Obstacles (No Inner Walls)
6.9. Challenge 8: Larger Maze with Inner</p>
        <p>Walls and Two Dynamic Obstacles
Challenge 6 eliminates the inner walls present in Chal- Expanding on the foundation set by Challenge 7,
Challenge 5 but retains the identical setup of six dynamic ob- lenge 8 introduces two dynamic obstacles to the maze.
stacles. This challenge assesses the robot’s performance This challenge amalgamates the complexities of
navigatin navigating through an open maze environment. ing in a larger maze with the additional challenge posed
by moving obstacles.
6.8. Challenge 7: Larger Maze with More</p>
        <p>Inner Walls
Challenge 7 introduces a larger maze with a heightened
count of inner walls. The robot is tasked with navigat- Finally, Challenge 9 preserves the larger maze and inner
ing through narrower passages and surmounting more walls featured in Challenge 8 but augments the number
intricate maze structures. of dynamic obstacles to six. This challenge poses an
exceptionally demanding scenario, evaluating the robot’s
capacity to navigate through intricate maze structures
and contend with a high density of dynamic obstacles.</p>
        <p>In summary, these nine challenges comprise a variety
of maze configurations and obstacle arrangements,
grad6.10. Challenge 9: Larger Maze with Inner</p>
        <p>Walls and Six Dynamic Obstacles
Model
CNN
LSTM
GRU
ViT
DQCNN
ually escalating in dificulty. Together, they facilitate a exhibits stable learning in the initial epochs. The
converthorough assessment of the robot’s navigation and ob- gence of the plots becomes evident from epoch 80.
stacle avoidance capabilities. Figure.2 provides a visual Additionally, the diminishing loss value as the model
representation of the diferent challenges discussed. progresses through epochs indicates that the model is
learning and refining its predictions. The training
accu6.11. EEG Results racy shows a consistent increase with each epoch,
signifying an improvement in the model’s ability to predict
According to the provided table (Tab.6.11) displaying the the training data. It commences at 48.08% and gradually
outcomes of models trained on the SEED IV dataset, each advances to 99.26%.
model underwent training three times, and the average, Similarly, the validation accuracy follows a comparable
as well as the variance of the scores, were computed. trajectory to the training accuracy, initiating at 46.58%
The DGCNN (Dynamic Graph Convolutional Neural Net- and progressing to 98.67%. This progression implies that
work) emerged as the top-performing model in terms of the model efectively generalizes and maintains
consisaccuracy, delivering the most favorable results. tent performance on unseen data.</p>
        <p>Specifically, DGCNN attained an average training ac- The final test accuracy also exhibits improvement over
curacy of 99.52% and an average validation accuracy the epochs, commencing at 47.63% and culminating at
of 99.03%. In comparison, ViT (Vision Transformer) 98.64%. This metric serves as a comprehensive gauge of
achieved an average training accuracy of 99.67% and an the model’s performance on the test set.
average validation accuracy of 98.60%. In summary, the training and validation accuracies</p>
        <p>The outstanding performance of DGCNN can be of the DGCNN model exhibit a correlated movement,
ascribed to its architectural features and capabilities. with the training accuracy marginally outperforming.
DGCNN employs graph convolutional layers, which The model showcases stable learning, begins
converadeptly capture and model intricate relationships and gence from epoch 80, and manifests enhancements in
dependencies within the data. This renders it particu- loss, training accuracy, validation accuracy, and final test
larly suitable for tasks involving graph-structured data, accuracy over the epochs. These outcomes signify that
such as the SEED IV dataset. Furthermore, the high accu- the model learns efectively, generalizes proficiently, and
racy demonstrated by DGCNN suggests its proficiency attains high accuracy on both the training and validation
in generalizing efectively to unseen data. datasets.</p>
        <p>In conclusion, the DGCNN model surpasses the other
models in accuracy on the SEED IV dataset. The triumph 6.11.2. Analysis of Loss Curves and Convergence
of this model can be attributed to its architectural design
and its capability to efectively capture complex
relationships and dependencies within the data.</p>
      </sec>
      <sec id="sec-6-3">
        <title>Throughout the 100 epochs, both the loss curves of</title>
        <p>DGCNN exhibit minimal variance observed across
multiple trials. This suggests that the model consistently
6.11.1. Analysis of DGCNN Training and converges towards similar local minima, yielding highly
Validation Results accurate predictions.</p>
        <p>Furthermore, the loss curve illustrates a gradual
deBased on the training accuracy and validation accuracy scent, initiating from an initial high value and steadily
deplots of DGCNN [Fig.3], it is observed that the plots ex- creasing throughout the training process. This indicates
hibit a synchronous pattern, with the training accuracy the model’s efective learning and adjustment of its
pamarginally surpassing the validation accuracy. Never- rameters to better fit the training data. After 100 epochs,
theless, the validation plot does not deviate significantly DGCNN attains an impressive loss value of 0.0005,
infrom the training plot. This suggests that our model dicating a high level of accuracy and robust predictive
learns efectively, demonstrates good generalization, and capability.</p>
        <p>This consistency underscores the stability and relia- nizing happiness, sadness, and neutral emotions. It also
bility of the solutions derived by DGCNN. In summary, performs commendably in detecting fear, with only a
the analysis of the loss curves of DGCNN unveils its slight misclassification rate.
remarkable capacity to minimize disparities between pre- In conclusion, the DGCNN model showcases
rodictions and ground truth values, resulting in highly ac- bust classification capabilities across all emotion classes.
curate models. DGCNN exhibits a robust ability to learn DGCNN delivers reliable predictions, establishing itself
and converge towards dependable solutions, making it a as a valuable tool for emotion classification tasks.
valuable tool for various applications.</p>
      </sec>
    </sec>
    <sec id="sec-7">
      <title>7. Conclusion</title>
      <sec id="sec-7-1">
        <title>6.11.3. Analysis of Confusion Matrix</title>
        <sec id="sec-7-1-1">
          <title>The confusion matrix provides valuable insights into the</title>
          <p>performance of classification models.</p>
          <p>In this study, we conducted a thorough examination of
the integration of deep reinforcement learning (DRL)
with emotion feedback. Through a series of experiments,
• Class 0 (Happiness):The DGCNN model achieves we identified optimal parameters to enhance learning
perfect accuracy (1.00) in classifying happiness, outcomes by incorporating both lidar and emotion
feedindicating no misclassifications in this category. back. Our investigations yielded improved overall
perfor• Class 1 (Sadness): Similarly, the DGCNN model mance and a notable reduction in the number of episodes
demonstrates flawless performance in identifying required for successful maze navigation. By
incorposadness, with a precision of 1.00. rating natural sensor feedback, particularly human
vi• Class 2 (Fear): The DGCNN model performs well sual perception and brain signals, we gained valuable
in detecting fear, with an accuracy of 0.98. How- insights into the potential of utilizing such feedback in
ever, it misclassifies a small portion (0.01) of the reinforcement learning tasks. Our findings highlight the
samples in this class as other emotions. efectiveness of combining deep reinforcement learning
• Class 3 (Neutral): The DGCNN model achieves with emotion feedback, opening up new possibilities for
perfect accuracy (1.00) in recognizing neutral leveraging natural sensor feedback and presenting
opemotions, implying no misclassifications in this portunities for future work in multi-robot scenarios and
category. transfer learning using brain signals beyond emotions.</p>
        </sec>
        <sec id="sec-7-1-2">
          <title>The DGCNN model demonstrates outstanding classification outcomes, achieving perfect accuracies in recog</title>
        </sec>
      </sec>
    </sec>
    <sec id="sec-8">
      <title>Acknowledgments</title>
      <sec id="sec-8-1">
        <title>This work has been developed at is.Lab() Intelligent Sys</title>
        <p>tems Laboratory at the Department of Computer, Control,
and Management Engineering, Sapienza University of
Rome (https:// islab.diag.uniroma1.it). The work has also
been partially supported from Italian Ministerial grant
PRIN 2022 “ISIDE: Intelligent Systems for Infrastructural
Diagnosis in smart-concretE”, n. 2022S88WAY - CUP
B53D2301318, and by the Age-It: Ageing Well in an
ageing society project, task 9.4.1 work package 4 spoke 9,
within topic 8 extended partnership 8, under the National
Recovery and Resilience Plan (PNRR), Mission 4
Component 2 Investment 1.3—Call for tender No. 1557 of
11/10/2022 of Italian Ministry of University and Research
funded by the European Union—NextGenerationEU, CUP
B53C22004090006.
51–59</p>
      </sec>
    </sec>
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