<!DOCTYPE article PUBLIC "-//NLM//DTD JATS (Z39.96) Journal Archiving and Interchange DTD v1.0 20120330//EN" "JATS-archivearticle1.dtd">
<article xmlns:xlink="http://www.w3.org/1999/xlink">
  <front>
    <journal-meta />
    <article-meta>
      <article-id pub-id-type="doi">10.1007/978-3-642-17746-0\_7</article-id>
      <title-group>
        <article-title>A Human-Centric Environment (HCE) Framework for Sustainable Production in a Bakery</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Luca Laboccetta</string-name>
          <email>luca.laboccetta@unical.it</email>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Giorgio Terracina</string-name>
          <email>giorgio.terracina@unical.it</email>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Francesco Calimeri</string-name>
          <email>francesco.calimeri@unical.it</email>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Simona Perri</string-name>
          <email>simona.perri@unical.it</email>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Massimiliano Rufolo</string-name>
          <email>massimiliano.rufolo@revelis.eu</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Davide Iacopino</string-name>
          <email>davide.iacopino@revelis.eu</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Marta Maria</string-name>
          <email>marta.maria@revelis.eu</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Salvatore Iiritano</string-name>
          <email>salvatore.iiritano@revelis.eu</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Revelis S.r.l.</institution>
          ,
          <addr-line>87036 Rende</addr-line>
          ,
          <country country="IT">Italy</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>University of Calabria</institution>
          ,
          <addr-line>87036 Rende</addr-line>
          ,
          <country country="IT">Italy</country>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2017</year>
      </pub-date>
      <volume>10587</volume>
      <fpage>96</fpage>
      <lpage>111</lpage>
      <abstract>
        <p>Employee well-being is an increasingly crucial factor for sustainability and eficiency in modern industry, especially within the context of Industry 5.0, which places humans at the center of production processes. This paper presents some work in progress towards the development of an innovative framework that aims to monitor operators' physical stress and well-being and then optimize task assignment in an industrial bakery environment. In particular, in this paper, we concentrate on the description of the general architecture and on the modules for stress prediction and management. This is part of a more general project developed under the NRRP MUR initiative FAIR (Future AI Research): Green-aware AI. Smartwatches and environmental sensors are the main sources of time-series biometric data. This data is used to predict future stress levels through an AI-based approach. These predictions are then used to dynamically reassign or pause operators. The goal is to minimize stress and prevent overload while maintaining adherence to the production plan. Preliminary results of some experiments conducted at a real Industrial Bakery Factory over a three-month period in the production, oven, and packaging departments, demonstrated how the integration of Internet of Everything (IoE) systems and AI can improve employee health and operational eficiency.</p>
      </abstract>
      <kwd-group>
        <kwd>eol&gt;Industry 5</kwd>
        <kwd>0</kwd>
        <kwd>Human-Centric AI</kwd>
        <kwd>Stream Reasoning</kwd>
        <kwd>Answer Set Programming (ASP)</kwd>
        <kwd>Employee Well-being</kwd>
        <kwd>Smart Factory</kwd>
        <kwd>IoT (Internet of Things)</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1. Introduction</title>
      <p>The landscape of modern manufacturing is rapidly evolving, driven by the principles of Industry 4.0
and increasingly, Industry 5.0. While Industry 4.0 focused on automation and data exchange, Industry
5.0 extends this vision by placing human well-being at the core of industrial processes, emphasizing
sustainability and human-centric approaches. In this paradigm, the health and psychophysical state of
employees are no longer secondary considerations but integral components of operational eficiency
and long-term business success. This shift necessitates advanced technological solutions capable of
real-time monitoring and adaptive management of human factors in dynamic industrial environments.
Specifically, the ability to accurately assess and predict critical human states, such as employee stress
levels, becomes paramount for proactive interventions and optimized resource allocation. This work
is devoted to present some ongoing work on the design and development of a system, named InCoP
(Industry 5.0 Collaborative Platform), which is part of the activities funded by the NRRP MUR initiative
FAIR (Future AI Research): Green-aware AI. The general aim is to create a versatile and scalable
technology platform capable of supporting the implementation of Industry 5.0 principles in various
industrial sectors. The platform is designed to be modular and adaptable, allowing the integration of
new features and technologies according to the specific needs of each application context. Main goals
of the platform consist in: (i) improve the eficiency and flexibility of the production process; (ii) create
a smarter production system that can learn from data and continuously improve its performance; (iii)
enable mass customization of products; (iv) demonstrate the potential impact of Industry 5.0 through the
definition of metrics and the evaluation of results obtained in the pilot company and other application
contexts.</p>
      <p>
        To address these complex requirements, two interconnected fields of Artificial Intelligence appear
to be particularly relevant. On the one hand, Machine/Deep Learning techniques [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ] are crucial for
discerning subtle patterns in physiological data and for forecasting future human states like stress. On
the other hand, Stream Reasoning (SR) [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ] has emerged as a promising field to address the complexities
of real-time data analysis and deductive inference over continuous, high-volume data streams.
      </p>
      <p>
        In the context of machine/deep learning approaches, Recurrent Neural Networks (RNNs) stand out
as a highly suitable class of neural networks for processing sequential data like time series, given their
inherent ability to maintain memory of past observations and leverage this history for predictions.
Among RNN architectures, Long Short-Term Memory (LSTM) [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ] and Gated Recurrent Unit (GRU)
networks are particularly efective due to their mechanisms for handling vanishing gradients and
capturing long-range dependencies, making them state-of-the-art for tasks such as stress prediction,
activity recognition, and general physiological monitoring.
      </p>
      <p>While machine/deep learning models excel at pattern recognition and prediction, their seamless
integration with symbolic reasoning systems poses unique challenges and opportunities for hybrid AI
approaches.</p>
      <p>
        As far as symbolic reasoning systems is concerned, Stream Reasoning (SR) [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ] has emerged as a
fundamental paradigm in the real-time data analysis landscape, where the incessant flow of information
demands not only the processing of data streams, but also the application of logical reasoning to extract
meaningful insights. This dual requirement is particularly relevant in domains with the presence
of heterogeneous and dynamic data streams, such as Smart Cities, the Internet of Things (IoT), or
Healthcare, where the need for timely and accurate decision making can be critical. In recent years,
the field has witnessed the development of various approaches to address the challenges posed by the
dynamic nature of (possibly big) data streams; indeed, diferent SR approaches have been proposed [
        <xref ref-type="bibr" rid="ref10 ref11 ref4 ref5 ref6 ref7 ref8 ref9">4,
5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18</xref>
        ] in contexts like Data Stream Management Systems (DSMS),
Complex Event Processing (CEP), Semantic Web, and Knowledge Representation and Reasoning (KRR).
      </p>
      <p>In particular, the present paper focuses on the Human-Centric Environment (HCE) framework for
sustainable production in a bakery, which is a part of the overall InCoP platform. Interestingly, HCE
integrates symbolic and sub-symbolic reasoning. Specifically, it uses Recurrent Neural Networks (RNNs)
to anticipate stress levels and dynamic task reassignment through Stream Reasoning to react in real
time to potentially harmful situations. The Stream Reasoning tool used in this project is DP-sr [19, 18].</p>
      <p>Through preliminary experiments, we aim to demonstrate how AI-driven stress monitoring,
augmented by machine learning (ML)-based stress prediction, can efectively optimize task assignments
and foster a safer, more eficient, and sustainable production process.</p>
    </sec>
    <sec id="sec-2">
      <title>2. Description of the HCE Framework</title>
      <p>In this Section, we first describe the general Human-Centric Environment (HCE) framework (shown in
Figure 1), and then concentrate on some of its main modules, namely data generation and collection
modules, stress prediction, and dynamic task re-assignment.</p>
      <p>Input data come from smartwatches worn by employees, suitably anonymized to avoid privacy issues,
and from environmental sensors strategically placed in the production departments. Data are ingested
and stored for subsequent elaboration. In parallel, acquired measurements are immediately queued and
fed to the stress prediction module. The module’s output is stored for next-step processing. The dynamic
task reassignment module continuously monitors ingested data and updates operator assignments if
needed. Alerts are sent back to individual smartwatches to privately notify workers when they need to
switch tasks or rest.</p>
      <p>It is worth pointing out that the framework shown in Figure 1 is only a part of the more general
architecture composing the InCoP platform. The design and description of the complete framework is
part of our future work.</p>
      <sec id="sec-2-1">
        <title>2.1. Data Generation and Collection</title>
        <p>The implementation of the system in the pilot bakery involved the installation of Internet of Everything
(IoE) devices in three key departments: production, ovens, and packaging. Involved devices include:
• Smartwatches: Worn by employees, these devices continuously monitor various biometric
parameters, including heart rate, blood pressure, blood oxygen level, body temperature, and
estimated stress level.
• Environmental Sensors (Airgloss): Strategically placed in the production departments, these
sensors detect real-time environmental conditions such as temperature and humidity.</p>
        <p>As far as data flow is concerned, data from smartwatches and environmental sensors are sent via
gateways to a Kafka-based messaging system. An Ingester component reads this data and stores it in
an Elasticsearch database.</p>
      </sec>
      <sec id="sec-2-2">
        <title>2.2. Stress prediction</title>
        <p>The Stress Prediction Algorithm is a dedicated component responsible for forecasting operators’ future
stress levels through a specialized Machine Learning (ML) model. This model leverages historical
stress trends, utilizing the 12 observations immediately preceding the prediction point. Forecasts are
generated autoregressively for 24 subsequent measurements, operating iteratively by incorporating
predicted values as new input data for subsequent predictions. The system dynamically acquires new
measurements directly from the Kafka queue for prediction, with the output subsequently fed back
into the same Kafka queue. The Ingester component then processes this output, transferring it to a
dedicated Elasticsearch index containing future stress level predictions. This index serves as the source
for both Grafana dashboards (for monitoring) and the dynamic assignment module (for operational
adjustments).</p>
        <p>Recurrent Neural Networks (RNNs) were identified as the most suitable class for time series analysis.
Their inherent structure allows them to retain a memory of past observations, thereby efectively
identifying relationships between input sequences and corresponding outputs.</p>
        <p>Testing involved multiple neural network architectures, typically concatenating a recurrent section
with a dense network segment. The recurrent part specifically explored diferent configurations of
well-known recurrent layers, such as Long Short-Term Memory (LSTM) and Gated Recurrent Unit
(GRU). The dense portion consisted of sequential layers, with each output vector passed through a
LeakyReLU activation function to enhance training eficiency by improving gradient propagation and
mitigating issues like the vanishing gradient problem. To combat overfitting and improve generalization,
Dropout and Batch Normalization layers were also integrated. Training management benefited from an
EarlyStopping mechanism, which halted training if no predictive improvements were observed over
a specified number of epochs on a validation set. The optimization target for training was the mean
square error loss function.</p>
        <p>The final architecture comprised 4 LSTM layers (with decreasing neuron counts), interspersed with
Batch Normalization and Dropout (excluding the initial layer), followed by 3 fully connected dense
layers (decreasing to 8 neurons). This final layer produces 8 outputs, as the network simultaneously
predicts the next stress level for each of the 8 smartwatches based on their respective historical stress
levels. The entire stress prediction component was developed in Python, utilizing the Tensorflow and
Keras libraries for neural network implementation. The model is summarized in Figure 2.</p>
        <p>Stress levels are classified into categories (Low: 0-50, Medium: 50-70, High: 70-100) based on
literaturedefined thresholds, emphasizing a well-being-oriented approach rather than medical diagnosis.</p>
      </sec>
      <sec id="sec-2-3">
        <title>2.3. Dynamic task re-assignment</title>
        <p>The Assignment Algorithm dynamically manages operator tasks to ensure a balance between physical
and mental well-being and production eficiency. The workflow of this module is depicted in Figure 3.
The module leverages the following data inputs:
• The real-time and predicted stress levels of operators (received from MongoDB every 5 minutes)
• The weekly shift rotation schedules</p>
        <p>The logic program within the DP-sr system dynamically adjusts operator assignments based on these
integrated data streams. Specifically, key rules in the program include:
• If an operator records four consecutive measurements with a medium stress level, they are
reassigned to a department where the average stress level of operators is low.
• If an operator records four consecutive measurements with a high stress level, they are put into
a "Rest" state until their stress level returns to Medium or Low.
• In order to keep compliance of the production plan, if necessary some other, not stressed, operator
is moved to the department just left by the stressed operator.</p>
        <p>The dual objectives of this module are to ensure compliance with the production plan, thereby
avoiding delays and ineficiencies, and to safeguard worker well-being by preventing physical and
mental overload. The DP-sr system processes the relevant data and then stores the updated operator
assignments back into MongoDB for system-wide access and visualization.</p>
      </sec>
    </sec>
    <sec id="sec-3">
      <title>3. Results and Discussion</title>
      <p>With a preliminary implementation of the HCE framework, we conducted a three-month
experimentation at a pilot Industrial Bakery. These preliminary experiments yielded significant results,
demonstrating the tangible benefits of a human-centric AI approach in a real-world industrial setting.
The evaluation focused on both business and technical Key Performance Indicators (KPIs).</p>
      <sec id="sec-3-1">
        <title>3.1. Business KPIs Achieved</title>
        <p>The project aimed to maximize productivity and ensure worker well-being, with the following outcomes:
• Maximize Cost Reduction (Equipment Overall Efectiveness): Improved from an AS-IS
value of 60% to an achieved value of 70% (with a TO-BE target of 80%).
• Maximize Personnel Productivity (Prevent accidents and safety risks): Maintained an
AS-IS value of 60%, with a TO-BE target of 70%. While not increased, the system contributed to
maintaining safety levels.
• Digital Transformation (Architecture integration): Achieved the TO-BE target of 1 from an
AS-IS value of 0.4, indicating successful integration of data sources, people, and smart objects
into a collaborative ecosystem.
• Performance Management (Worker satisfaction, idle time, production delays): Improved
from an AS-IS value of 60% to an achieved value of 70% (with a TO-BE target of 80%), reflecting
increased worker satisfaction and optimized time utilization.</p>
        <p>Overall, the system’s interventions led to increased safety at work through proactive management of
fatigue and stress, resulting in a reduction in accident risk and improved worker well-being. Dynamic
task management also contributed to increased productivity by adapting worker roles to their physical
and psychological conditions, reducing fatigue-related errors.</p>
      </sec>
      <sec id="sec-3-2">
        <title>3.2. Technical KPIs Achieved</title>
        <p>From a technical point of view, the system demonstrated robust performance and scalability:
• Detection of workers’ vital parameters: The system successfully achieved its TO-BE value,
providing 12 detections per hour with 5-minute timestamps.
• Temperature and humidity monitoring: Similarly, environmental parameters were detected
at the target frequency of 12 detections per hour.
• Scalability and Interoperability (Number of sources, people, and built-in smart objects):
The system achieved its TO-BE target of 8, from an AS-IS value of &gt;5, indicating successful
integration of a diverse set of data sources and smart objects.</p>
        <p>These technical achievements underscore the robustness and reliability of the data collection and
processing pipeline, crucial for real-time SR.</p>
      </sec>
      <sec id="sec-3-3">
        <title>3.3. Barriers Faced and Lessons Learned</title>
        <p>The implementation phase encountered several challenges:
• Sensor malfunction and connectivity issues: Environmental sensors provided inaccurate
readings, and connectivity between devices and the central system was sometimes unstable.
Solutions involved regular maintenance, periodic calibrations, and corporate Wi-Fi enhancements
with backup solutions.
• Compliance and privacy concerns: Staf raised concerns about data privacy, especially
sensitive health information. This was addressed through awareness sessions, GDPR compliance
(anonymization, restricted access), and transparent communication.
• Device adoption resistance and data quality: Some workers were reluctant to use
smartwatches, and collected data could be incomplete or noisy. This required ongoing support, targeted
training, and data validation techniques.</p>
        <p>Key lessons learned emphasize the importance of continuous staf education, robust data management
and regulatory compliance, technological robustness (preventative maintenance for hardware),
adaptability of AI algorithms, and efective internal communication among stakeholders. These lessons are
vital for the scalability and long-term success of such complex Industry 5.0 projects.</p>
      </sec>
    </sec>
    <sec id="sec-4">
      <title>4. Conclusions and Future Work</title>
      <p>This paper presented some preliminary results on the ongoing design, development and testing of the
InCoP platform. In particular, we focused on the Human-Centric Environment Framework developed for
a bakery towards sustainable production. Preliminary experimental results demonstrated the practical
feasibility and tangible benefits of using a mixture of ML and ASP-based SR approaches to address
operator stress and dynamic task assignment. The proposed approach resulted promising to enhance
employee well-being and operational eficiency. The achieved business and technical KPIs validate the
system’s efectiveness in a real-world industrial context, highlighting improvements in productivity,
worker satisfaction, and safety. Future work include not only the design and implementation of other
components of the InCoP platform, but also further refinements in data acquisition and elaboration in
order to further improve KPIs and staf engagement in application development and testing.</p>
    </sec>
    <sec id="sec-5">
      <title>Declaration on Generative AI</title>
      <p>The author(s) confirm that no Generative AI tools were used in the creation of this article.</p>
    </sec>
    <sec id="sec-6">
      <title>Acknowledgments</title>
      <p>We acknowledge financial support from projects: PNRR MUR PE0000013-FAIR, Fa.Per.M.E. (CUP
H53C22000640006), NutriDieMMe (CUP H53C22000940001). Francesco Calimeri is member of the
Gruppo Nazionale Calcolo Scientifico-Istituto Nazionale di Alta Matematica (GNCS-INdAM).</p>
    </sec>
  </body>
  <back>
    <ref-list>
      <ref id="ref1">
        <mixed-citation>
          [1]
          <string-name>
            <given-names>I. H.</given-names>
            <surname>Sarker</surname>
          </string-name>
          ,
          <article-title>Deep learning: A comprehensive overview on techniques, taxonomy, applications and research directions</article-title>
          ,
          <source>SN Comput. Sci. 2</source>
          (
          <year>2021</year>
          )
          <article-title>420</article-title>
          . URL: https://doi.org/10.1007/s42979-021-00815-1. doi:
          <volume>10</volume>
          .1007/S42979-021-00815-1.
        </mixed-citation>
      </ref>
      <ref id="ref2">
        <mixed-citation>
          [2]
          <string-name>
            <given-names>D.</given-names>
            <surname>Dell'Aglio</surname>
          </string-name>
          ,
          <string-name>
            <given-names>E. D.</given-names>
            <surname>Valle</surname>
          </string-name>
          ,
          <string-name>
            <surname>F. van Harmelen</surname>
          </string-name>
          ,
          <string-name>
            <given-names>A.</given-names>
            <surname>Bernstein</surname>
          </string-name>
          ,
          <article-title>Stream reasoning: A survey and outlook</article-title>
          ,
          <source>Data Sci. 1</source>
          (
          <year>2017</year>
          )
          <fpage>59</fpage>
          -
          <lpage>83</lpage>
          . URL: https://doi.org/10.3233/DS-170006. doi:
          <volume>10</volume>
          .3233/DS-170006.
        </mixed-citation>
      </ref>
      <ref id="ref3">
        <mixed-citation>
          [3]
          <string-name>
            <given-names>S.</given-names>
            <surname>Hochreiter</surname>
          </string-name>
          ,
          <string-name>
            <given-names>J.</given-names>
            <surname>Schmidhuber</surname>
          </string-name>
          ,
          <article-title>Long short-term memory</article-title>
          ,
          <source>Neural Comput. 9</source>
          (
          <year>1997</year>
          )
          <fpage>1735</fpage>
          -
          <lpage>1780</lpage>
          . URL: https://doi.org/10.1162/neco.
          <year>1997</year>
          .
          <volume>9</volume>
          .8.1735. doi:
          <volume>10</volume>
          .1162/neco.
          <year>1997</year>
          .
          <volume>9</volume>
          .8.1735.
        </mixed-citation>
      </ref>
      <ref id="ref4">
        <mixed-citation>
          [4]
          <string-name>
            <given-names>D. F.</given-names>
            <surname>Barbieri</surname>
          </string-name>
          ,
          <string-name>
            <given-names>D.</given-names>
            <surname>Braga</surname>
          </string-name>
          ,
          <string-name>
            <given-names>S.</given-names>
            <surname>Ceri</surname>
          </string-name>
          ,
          <string-name>
            <given-names>E. D.</given-names>
            <surname>Valle</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M.</given-names>
            <surname>Grossniklaus</surname>
          </string-name>
          ,
          <string-name>
            <surname>C-</surname>
          </string-name>
          <article-title>SPARQL: a continuous query language for RDF data streams</article-title>
          ,
          <source>Int. J. Semantic Comput</source>
          .
          <volume>4</volume>
          (
          <issue>2010</issue>
          )
          <fpage>3</fpage>
          -
          <lpage>25</lpage>
          . URL: https://doi.org/10. 1142/S1793351X10000936. doi:
          <volume>10</volume>
          .1142/S1793351X10000936.
        </mixed-citation>
      </ref>
      <ref id="ref5">
        <mixed-citation>
          [5]
          <string-name>
            <given-names>D. L.</given-names>
            <surname>Phuoc</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M.</given-names>
            <surname>Dao-Tran</surname>
          </string-name>
          ,
          <string-name>
            <given-names>J. X.</given-names>
            <surname>Parreira</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M.</given-names>
            <surname>Hauswirth</surname>
          </string-name>
          ,
          <article-title>A native and adaptive approach for unified processing of linked streams and linked data</article-title>
          , in: L.
          <string-name>
            <surname>Aroyo</surname>
            ,
            <given-names>C.</given-names>
          </string-name>
          <string-name>
            <surname>Welty</surname>
            ,
            <given-names>H.</given-names>
          </string-name>
          <string-name>
            <surname>Alani</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          <string-name>
            <surname>Taylor</surname>
          </string-name>
          , A.
          <string-name>
            <surname>Bernstein</surname>
            ,
            <given-names>L.</given-names>
          </string-name>
          <string-name>
            <surname>Kagal</surname>
            ,
            <given-names>N. F.</given-names>
          </string-name>
          <string-name>
            <surname>Noy</surname>
          </string-name>
          , E. Blomqvist (Eds.),
          <source>The Semantic Web - ISWC 2011 - 10th International Semantic Web Conference</source>
          , Bonn, Germany,
          <source>October 23-27</source>
          ,
          <year>2011</year>
          , Proceedings,
          <string-name>
            <surname>Part</surname>
            <given-names>I</given-names>
          </string-name>
          , volume
          <volume>7031</volume>
          of Lecture Notes in Computer Science, Springer,
          <year>2011</year>
          , pp.
          <fpage>370</fpage>
          -
          <lpage>388</lpage>
          . URL: https: //doi.org/10.1007/978-3-
          <fpage>642</fpage>
          -25073-6_
          <fpage>24</fpage>
          . doi:
          <volume>10</volume>
          .1007/978-3-
          <fpage>642</fpage>
          -25073-6\_
          <fpage>24</fpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref6">
        <mixed-citation>
          [6]
          <string-name>
            <given-names>J.</given-names>
            <surname>Hoeksema</surname>
          </string-name>
          ,
          <string-name>
            <given-names>S.</given-names>
            <surname>Kotoulas</surname>
          </string-name>
          ,
          <article-title>High-performance distributed stream reasoning using s4</article-title>
          ,
          <source>in: Ordring Workshop at ISWC</source>
          <year>2011</year>
          ,
          <year>2011</year>
          , pp.
          <fpage>1</fpage>
          -
          <lpage>8</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref7">
        <mixed-citation>
          [7]
          <string-name>
            <given-names>T.</given-names>
            <surname>Pham</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M. I.</given-names>
            <surname>Ali</surname>
          </string-name>
          ,
          <string-name>
            <given-names>A.</given-names>
            <surname>Mileo</surname>
          </string-name>
          , C-ASP:
          <article-title>continuous asp-based reasoning over RDF streams</article-title>
          , in: M.
          <string-name>
            <surname>Balduccini</surname>
            ,
            <given-names>Y.</given-names>
          </string-name>
          <string-name>
            <surname>Lierler</surname>
          </string-name>
          , S. Woltran (Eds.),
          <source>Logic Programming and Nonmonotonic Reasoning - 15th International Conference, LPNMR 2019</source>
          , Philadelphia, PA, USA, June 3-7,
          <year>2019</year>
          , Proceedings, volume
          <volume>11481</volume>
          of Lecture Notes in Computer Science, Springer,
          <year>2019</year>
          , pp.
          <fpage>45</fpage>
          -
          <lpage>50</lpage>
          . URL: https://doi.org/ 10.1007/978-3-
          <fpage>030</fpage>
          -20528-
          <issue>7</issue>
          _4. doi:
          <volume>10</volume>
          .1007/978-3-
          <fpage>030</fpage>
          -20528-7\_4.
        </mixed-citation>
      </ref>
      <ref id="ref8">
        <mixed-citation>
          [8]
          <string-name>
            <given-names>A.</given-names>
            <surname>Mileo</surname>
          </string-name>
          ,
          <string-name>
            <given-names>A.</given-names>
            <surname>Abdelrahman</surname>
          </string-name>
          ,
          <string-name>
            <given-names>S.</given-names>
            <surname>Policarpio</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M.</given-names>
            <surname>Hauswirth</surname>
          </string-name>
          ,
          <article-title>Streamrule: A nonmonotonic stream reasoning system for the semantic web</article-title>
          , in: W. Faber, D. Lembo (Eds.),
          <source>Web Reasoning and Rule Systems - 7th International Conference, RR</source>
          <year>2013</year>
          ,
          <article-title>Mannheim</article-title>
          , Germany,
          <source>July 27-29</source>
          ,
          <year>2013</year>
          . Proceedings, volume
          <volume>7994</volume>
          of Lecture Notes in Computer Science, Springer,
          <year>2013</year>
          , pp.
          <fpage>247</fpage>
          -
          <lpage>252</lpage>
          . URL: https://doi.org/10.1007/978-3-
          <fpage>642</fpage>
          -39666-3_
          <fpage>23</fpage>
          . doi:
          <volume>10</volume>
          .1007/978-3-
          <fpage>642</fpage>
          -39666-3\_
          <fpage>23</fpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref9">
        <mixed-citation>
          [9]
          <string-name>
            <given-names>T. M.</given-names>
            <surname>Do</surname>
          </string-name>
          ,
          <string-name>
            <given-names>S. W.</given-names>
            <surname>Loke</surname>
          </string-name>
          ,
          <string-name>
            <given-names>F.</given-names>
            <surname>Liu</surname>
          </string-name>
          ,
          <article-title>Answer set programming for stream reasoning</article-title>
          , in: C. J.
          <string-name>
            <surname>Butz</surname>
          </string-name>
          , P. Lingras (Eds.),
          <source>Advances in Artificial Intelligence - 24th Canadian Conference on Artificial Intelligence</source>
          ,
          <source>Canadian AI</source>
          <year>2011</year>
          ,
          <article-title>St</article-title>
          . John's, Canada, May
          <volume>25</volume>
          -27,
          <year>2011</year>
          . Proceedings, volume
          <volume>6657</volume>
          of Lecture Notes in Computer Science, Springer,
          <year>2011</year>
          , pp.
          <fpage>104</fpage>
          -
          <lpage>109</lpage>
          . URL: https://doi.org/10.1007/978-3-
          <fpage>642</fpage>
          -21043-3_
          <fpage>13</fpage>
          . doi:
          <volume>10</volume>
          .1007/978-3-
          <fpage>642</fpage>
          -21043-3\_
          <fpage>13</fpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref10">
        <mixed-citation>
          [10]
          <string-name>
            <given-names>M.</given-names>
            <surname>Gebser</surname>
          </string-name>
          ,
          <string-name>
            <given-names>T.</given-names>
            <surname>Grote</surname>
          </string-name>
          ,
          <string-name>
            <given-names>R.</given-names>
            <surname>Kaminski</surname>
          </string-name>
          , T. Schaub,
          <article-title>Reactive answer set programming</article-title>
          , in: J. P. Delgrande, W. Faber (Eds.),
          <source>Logic Programming and Nonmonotonic Reasoning - 11th International Conference, LPNMR 2011</source>
          , Vancouver, Canada, May
          <volume>16</volume>
          -19,
          <year>2011</year>
          . Proceedings, volume
          <volume>6645</volume>
          of Lecture Notes in Computer Science, Springer,
          <year>2011</year>
          , pp.
          <fpage>54</fpage>
          -
          <lpage>66</lpage>
          . URL: https://doi.org/10.1007/978-3-
          <fpage>642</fpage>
          -20895-
          <issue>9</issue>
          _7. doi:
          <volume>10</volume>
          .1007/978-3-
          <fpage>642</fpage>
          -20895-9\_7.
        </mixed-citation>
      </ref>
      <ref id="ref11">
        <mixed-citation>
          [11]
          <string-name>
            <given-names>J.</given-names>
            <surname>Calbimonte</surname>
          </string-name>
          , Ó. Corcho,
          <string-name>
            <given-names>A. J. G.</given-names>
            <surname>Gray</surname>
          </string-name>
          ,
          <article-title>Enabling ontology-based access to streaming data sources</article-title>
          , in: P.
          <string-name>
            <given-names>F.</given-names>
            <surname>Patel-Schneider</surname>
          </string-name>
          ,
          <string-name>
            <given-names>Y.</given-names>
            <surname>Pan</surname>
          </string-name>
          ,
          <string-name>
            <given-names>P.</given-names>
            <surname>Hitzler</surname>
          </string-name>
          ,
          <string-name>
            <given-names>P.</given-names>
            <surname>Mika</surname>
          </string-name>
          ,
          <string-name>
            <given-names>L.</given-names>
            <surname>Zhang</surname>
          </string-name>
          ,
          <string-name>
            <given-names>J. Z.</given-names>
            <surname>Pan</surname>
          </string-name>
          ,
          <string-name>
            <given-names>I.</given-names>
            <surname>Horrocks</surname>
          </string-name>
          ,
          <string-name>
            <surname>B.</surname>
          </string-name>
          Glimm (Eds.),
          <source>The Semantic Web - ISWC 2010 - 9th International Semantic Web Conference, ISWC 2010</source>
          , Shanghai, China, November 7-
          <issue>11</issue>
          ,
          <year>2010</year>
          ,
          <string-name>
            <given-names>Revised</given-names>
            <surname>Selected</surname>
          </string-name>
          <string-name>
            <given-names>Papers</given-names>
            ,
            <surname>Part</surname>
          </string-name>
          <string-name>
            <surname>I</surname>
          </string-name>
          , volume
          <volume>6496</volume>
          of Lecture Notes in
        </mixed-citation>
      </ref>
    </ref-list>
  </back>
</article>