<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE article PUBLIC "-//NLM//DTD JATS (Z39.96) Journal Publishing DTD v1.0 20120330//EN" "http://jats.nlm.nih.gov/publishing/1.1/JATS-journalpublishing1.dtd">
<article xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" article-type="research-article" dtd-version="1.0">
<front>
<journal-meta>
<journal-id journal-id-type="pmc">CMC</journal-id>
<journal-id journal-id-type="nlm-ta">CMC</journal-id>
<journal-id journal-id-type="publisher-id">CMC</journal-id>
<journal-title-group>
<journal-title>Computers, Materials &#x0026; Continua</journal-title>
</journal-title-group>
<issn pub-type="epub">1546-2226</issn>
<issn pub-type="ppub">1546-2218</issn>
<publisher>
<publisher-name>Tech Science Press</publisher-name>
<publisher-loc>USA</publisher-loc>
</publisher>
</journal-meta>
<article-meta>
<article-id pub-id-type="publisher-id">18179</article-id>
<article-id pub-id-type="doi">10.32604/cmc.2021.018179</article-id>
<article-categories>
<subj-group subj-group-type="heading">
<subject>Article</subject>
</subj-group>
</article-categories>
<title-group>
<article-title>Dynamic Voting Classifier for Risk Identification in Supply Chain 4.0</article-title>
<alt-title alt-title-type="left-running-head">Dynamic Voting Classifier for Risk Identification in Supply Chain 4.0</alt-title>
<alt-title alt-title-type="right-running-head">Dynamic Voting Classifier for Risk Identification in Supply Chain 4.0</alt-title>
</title-group>
<contrib-group content-type="authors">
<contrib id="author-1" contrib-type="author">
<name name-style="western">
<surname>Salamai</surname>
<given-names>Abdullah Ali</given-names>
</name>
<xref ref-type="aff" rid="aff-1">1</xref>
</contrib>
<contrib id="author-2" contrib-type="author">
<name name-style="western">
<surname>El-kenawy</surname>
<given-names>El-Sayed M.</given-names>
</name>
<xref ref-type="aff" rid="aff-2">2</xref></contrib>
<contrib id="author-3" contrib-type="author" corresp="yes">
<name name-style="western">
<surname>Abdelhameed</surname>
<given-names>Ibrahim</given-names>
</name>
<xref ref-type="aff" rid="aff-3">3</xref><email>afai79@mans.edu.eg</email></contrib>
<aff id="aff-1"><label>1</label><institution>Community college, Jazan University</institution>, <addr-line>Jazan</addr-line>, <country>Kingdom of Saudi Arabia</country></aff>
<aff id="aff-2"><label>2</label><institution>Delta Higher Institute of Engineering and Technology</institution>, <addr-line>Mansoura</addr-line>, <country>Egypt</country></aff>
<aff id="aff-3"><label>3</label><institution>Faculty of Engineering, Mansoura University</institution>, <addr-line>Mansoura</addr-line>, <country>Egypt</country></aff>
</contrib-group>
<author-notes><corresp id="cor1">&#x002A;Corresponding Author: Ibrahim Abdelhameed. Email: <email>afai79@mans.edu.eg</email></corresp></author-notes>
<pub-date pub-type="epub" date-type="pub" iso-8601-date="2021-08-23">
<day>23</day>
<month>8</month>
<year>2021</year>
</pub-date>
<volume>69</volume>
<issue>3</issue>
<fpage>3749</fpage>
<lpage>3766</lpage>
<history>
<date date-type="received">
<day>28</day>
<month>2</month>
<year>2021</year>
</date>
<date date-type="accepted">
<day>5</day>
<month>5</month>
<year>2021</year>
</date>
</history>
<permissions>
<copyright-statement>&#x00A9; 2021 Salamai, El-kenawy and Abdelhameed</copyright-statement>
<copyright-year>2021</copyright-year>
<copyright-holder>Salamai, El-kenawy and Abdelhameed</copyright-holder>
<license xlink:href="https://creativecommons.org/licenses/by/4.0/">
<license-p>This work is licensed under a <ext-link ext-link-type="uri" xlink:type="simple" xlink:href="https://creativecommons.org/licenses/by/4.0/">Creative Commons Attribution 4.0 International License</ext-link>, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.</license-p>
</license>
</permissions>
<self-uri content-type="pdf" xlink:href="TSP_CMC_18179.pdf"></self-uri>
<abstract>
<p>Supply chain 4.0 refers to the fourth industrial revolution&#x2019;s supply chain management systems, which integrate the supply chain&#x2019;s manufacturing operations, information technology, and telecommunication processes. Although supply chain 4.0 aims to improve supply chains&#x2019; production systems and profitability, it is subject to different operational and disruptive risks. Operational risks are a big challenge in the cycle of supply chain 4.0 for controlling the demand and supply operations to produce and deliver products across IT systems. This paper proposes a voting classifier to identify the operational risks in the supply chain 4.0 based on a Sine Cosine Dynamic Group (SCDG) algorithm. Exploration and exploitation mechanisms of the basic Sine Cosine Algorithm (CSA) are adjusted and controlled by two groups of agents that can be changed dynamically during the iterations. External and internal features were collected and analyzed from different data sources of service level agreements and transaction data from various KSA firms to validate the proposed algorithm&#x2019;s efficiency. A balanced accuracy of 0.989 and a Mean Square Error (MSE) of 0.0476 were achieved compared with other optimization-based classifier techniques. A one-way analysis of variance (ANOVA) and Wilcoxon rank-sum tests were performed to show the superiority of the proposed SCDG algorithm. Thus, the experimental results indicate the effectiveness of the proposed SCDG algorithm-based voting classifier.</p>
</abstract>
<kwd-group kwd-group-type="author">
<kwd>Machine learning</kwd>
<kwd>artificial intelligence</kwd>
<kwd>supply chain 4.0</kwd>
<kwd>risk factors</kwd>
<kwd>risk management</kwd>
</kwd-group>
</article-meta>
</front>
<body>
<sec id="s1">
<label>1</label>
<title>Introduction</title>
<p>Given the array of uncertainties in supply chain management, supply chain performance is vulnerable to several risk factors. Supply chain risk is defined as the probability of a risk event that impacts the supply chain at the micro or macro level and leads to disruption at any stage of supply chain operations [<xref ref-type="bibr" rid="ref-1">1</xref>]. Risk management is the process of assessing and predicting risks to identify risk events to minimize or avoid their effects [<xref ref-type="bibr" rid="ref-2">2</xref>]. Supply risk can be categorized into disruption type or operation type [<xref ref-type="bibr" rid="ref-3">3</xref>&#x2013;<xref ref-type="bibr" rid="ref-5">5</xref>]. The risk associated with natural disasters, such as earthquake or flooding, is difficult to control. Operational risk leads suboptimal or failed supply and demand operations while delivering or producing final products [<xref ref-type="bibr" rid="ref-6">6</xref>]. The quality of products or delivery of products or services to end customers is a challenge that can be controlled and predicted if it is well-recognized [<xref ref-type="bibr" rid="ref-7">7</xref>]. These events are categorized based on supply chain components such as planning, sourcing, making, delivery, and return [<xref ref-type="bibr" rid="ref-8">8</xref>].</p>
<p>Operational risk events can arise from external sources and inherent supply chain features. The probability of external risk events may affect the whole supply chain, leading firms to declare bankruptcy or fall behind in their finances [<xref ref-type="bibr" rid="ref-9">9</xref>]. The supply chain depends on defining and controlling the external factors by an appropriate method [<xref ref-type="bibr" rid="ref-10">10</xref>]. For example, to increase the sustainability of profits, supply chain firms should take action on factors from external risks or internal risks for maintaining their business [<xref ref-type="bibr" rid="ref-11">11</xref>]. Defining risks is one of the significant challenges for the success of managing risks and decreasing supply chain firms&#x2019; uncertainty [<xref ref-type="bibr" rid="ref-12">12</xref>]. External risk events that occur within the internal processes of supply chain 4.0 can cause issues if not planned adequately and affect supply chain firms if methods to mitigate the risks are lacking. Thus, the supply chain risk assessment process has become a necessity today.</p>
<p>A precise analysis of managing risks through better methods is necessary for supply chain 4.0 risk management. Identification and mitigation processes are the main elements of controlling risk events and that includes the concept of understanding the reasons for risk probability and impacts. Management of risk is an essential component of risk analysis, and it can improve decision making for mitigating risks. A supply chain&#x2019;s profitability depends mainly on identifying and controlling external and internal factors through appropriate responsiveness, efficiency, and reliability [<xref ref-type="bibr" rid="ref-10">10</xref>]. To sustain firms&#x2019; profitability levels, supply chains must respond rapidly to internal and external risk events to maintain their businesses effectively and dynamically [<xref ref-type="bibr" rid="ref-11">11</xref>&#x2013;<xref ref-type="bibr" rid="ref-13">13</xref>]. Different researchers have applied several methods, including quantitative methods, for defining risk events in the supply chain&#x2019;s operational processes [<xref ref-type="bibr" rid="ref-14">14</xref>&#x2013;<xref ref-type="bibr" rid="ref-16">16</xref>].</p>
<p>This paper focuses on managing risk in supply chain 4.0 by identifying, assessing, and mitigating external risk events. It proposes a voting classifier based on a Sine Cosine Dynamic Group (SCDG) optimization algorithm to identify and quantify external and internal risk events. The proposed method helps firms mitigate risk events. Exterior and interior features were collected and analyzed from data sources such as service level agreements and Kingdom of Saudi Arabia&#x2019;s (KSA) firms&#x2019; transaction data to validate the proposed algorithm&#x2019;s efficiency. Experiments were designed to determine the proposed SCDG algorithm-based voting classifier&#x2019;s effectiveness using balanced accuracy and Mean Square Error (MSE) metrics. Results were compared with other optimization-based classifier techniques. The proposed voting SCDG classifier was compared with Particle Swarm Optimization (PSO) [<xref ref-type="bibr" rid="ref-17">17</xref>,<xref ref-type="bibr" rid="ref-18">18</xref>], Whale Optimization Algorithm (WOA) [<xref ref-type="bibr" rid="ref-19">19</xref>,<xref ref-type="bibr" rid="ref-20">20</xref>], Grey Wolf Optimizer (GWO) [<xref ref-type="bibr" rid="ref-21">21</xref>,<xref ref-type="bibr" rid="ref-22">22</xref>], and Genetic Algorithm (GA)-based [<xref ref-type="bibr" rid="ref-23">23</xref>,<xref ref-type="bibr" rid="ref-24">24</xref>] voting classifier algorithms. One-way analysis of variance (ANOVA) and Wilcoxon rank-sum tests were performed to test the proposed SCDG algorithm&#x2019;s superiority.</p>
<p>This paper is organized as follows. Section 2 discusses the background and related work of this research. Section 3 explains the artificial intelligence methods for managing risk in supply chain 4.0. Section 4 discusses the proposed Sine Cosine Dynamic Group Algorithm. Section 5 describes the experimental results. Finally, Section 6 presents the conclusions of the study.</p>
</sec>
<sec id="s2">
<label>2</label>
<title>Related Work</title>
<p>Different external risk events affect supply chain performance and cause harm to a supply chain&#x2019;s internal processes, which can lead to severe financial issues that drag down firms [<xref ref-type="bibr" rid="ref-14">14</xref>,<xref ref-type="bibr" rid="ref-15">15</xref>]. The authors in [<xref ref-type="bibr" rid="ref-8">8</xref>] defined risk management as helping firms describe risk before it happens and trying to mitigate it in any possible way. Most of the previous studies have categorized risk management into three steps: risk identification, risk assessment, and risk mitigation. There have been multiple descriptions of the risk management process from different authors. The authors in [<xref ref-type="bibr" rid="ref-8">8</xref>,<xref ref-type="bibr" rid="ref-25">25</xref>,<xref ref-type="bibr" rid="ref-26">26</xref>] described risk identification as the first step in risk management, which can help the decision maker manage the risk if defined well.</p>
<p>The authors in [<xref ref-type="bibr" rid="ref-27">27</xref>&#x2013;<xref ref-type="bibr" rid="ref-29">29</xref>] explained risk assessment as the method or system that helps a firm assess and evaluate the impact of historical data of the firm. In [<xref ref-type="bibr" rid="ref-16">16</xref>,<xref ref-type="bibr" rid="ref-30">30</xref>,<xref ref-type="bibr" rid="ref-31">31</xref>], the authors discussed risk mitigation as the method that helps the decision makers quantify risk before it occurs, thus allowing the firm to prevent it. It is essential to study the external risk of supply chain 4.0 to find a better method for measuring its impact on the supply chain. For example, DHL provides Resilience 360, which helps firms map the supply chain end to end and build a system for identifying critical risks by alerting stakeholders on time, which helps mitigate the risk [<xref ref-type="bibr" rid="ref-32">32</xref>]. Many recent machine learning techniques, such as [<xref ref-type="bibr" rid="ref-33">33</xref>&#x2013;<xref ref-type="bibr" rid="ref-39">39</xref>], can be applied to such problems. <xref ref-type="fig" rid="fig-1">Fig. 1</xref> shows the importance of industry 4.0 in the supply chain, which can help firms to attain competitive and sustainable advantages. This paper focuses on quantifying risk events for improving supply chain 4.0 firms&#x2019; decision making.</p>
<fig id="fig-1">
<label>Figure 1</label>
<caption>
<title>Industry 4.0 in a supply chain smart factory</title>
</caption>
<graphic mimetype="image" mime-subtype="png" xlink:href="CMC_18179-fig-1.png"/>
</fig>
</sec>
<sec id="s3">
<label>3</label>
<title>Background</title>
<sec id="s3_1">
<label>3.1</label>
<title>Supply Chain 4.0 Operation</title>
<p>Industry 4.0 refers to the fourth industrial revolution and a new model of an intelligent system that helps enterprises in the production and manufacturing environment. It emphasizes global networks in a smart factory for controlling and exchanging information [<xref ref-type="bibr" rid="ref-40">40</xref>]. Supply chain 4.0 consists of independent activities that are geographically separated, combined in various ways, and linked through varied companies, resulting in a capability to respond to consumers&#x2019; necessities and needs. As shown in <xref ref-type="fig" rid="fig-2">Fig. 2</xref>, the dependencies in a supply chain 4.0 include customers, vendors, devices, manufacturing plants, and other physical source systems [<xref ref-type="bibr" rid="ref-41">41</xref>].</p>
<fig id="fig-2">
<label>Figure 2</label>
<caption>
<title>The context of the supply chain within industry 4.0</title>
</caption>
<graphic mimetype="image" mime-subtype="png" xlink:href="CMC_18179-fig-2.png"/>
</fig>
<p>Supply chain 4.0 is a disruption that causes firms to rethink the components, processes, and designs of their supply chain. In response to client requirements and the need for speedy for fulfillment, numerous strategies have arisen that have changed typical working techniques. Furthermore, the demand for naturalization and supply establishments can also be used to reach the next horizon of operational efficiency, establish the company as an electronic supply chain, as well as change the service provider right into a digital supply chain [<xref ref-type="bibr" rid="ref-42">42</xref>]. To take advantage of these trends and deal with changing requirements, supply chains need to become faster, more credible, and more accurate.</p>
<p>Different researchers have attempted to apply various techniques for defining risks, which is the first step in risk management [<xref ref-type="bibr" rid="ref-43">43</xref>&#x2013;<xref ref-type="bibr" rid="ref-45">45</xref>]. The authors in [<xref ref-type="bibr" rid="ref-46">46</xref>] stated that artificial intelligence is the technique of the future, and it will help capture risk events automatically by finding the correlation between risk features and labels, as shown in <xref ref-type="table" rid="table-1">Tab. 1</xref>. One of the significant challenges in previous studies was the lack of real data or visible data sources that help yield accurate results for defining risk events by categorizing the firm&#x2019;s decision when risks occur into three decisions: avoid, reduce, or accept the risks. The proposed framework quantifies the risk as either low, medium, or high, which helps firms make better decisions without uncertainty. <xref ref-type="fig" rid="fig-3">Fig. 3</xref> shows the internal and external risk events that impact the processes of supply chain 4.0.</p>
<table-wrap id="table-1">
<label>Table 1</label>
<caption>
<title>Attributes and risk labels of the companies&#x2019; dataset</title>
</caption>
<table>
<colgroup>
<col/>
<col/>
<col/>
<col/>
</colgroup>
<thead>
<tr>
<th>Attribute</th>
<th>Stream of risks</th>
<th>Description</th>
<th></th>
</tr>
</thead>
<tbody>
<tr>
<td>Minimum quantity</td>
<td>Interior</td>
<td>Is the minimum number of materials that firms need to order</td>
<td/>
</tr>
<tr>
<td>Quantity on hand</td>
<td>Interior</td>
<td>Are the materials that available in the firm&#x2019;s inventories</td>
<td/>
</tr>
<tr>
<td>Estimated date for receipt</td>
<td>External</td>
<td>Is the predictable date for delivering orders in the long or short term</td>
<td/>
</tr>
<tr>
<td>Quantity to buy</td>
<td>External</td>
<td>Is the number of materials that firms need to purchase at one time</td>
<td/>
</tr>
<tr>
<td>Price</td>
<td>External</td>
<td>Is the suppliers&#x2019; plans for selling their products</td>
<td/>
</tr>
<tr>
<td>Safety stock</td>
<td>Interior/exterior</td>
<td>Are the extra materials available in the inventory reserved for reducing the shortages</td>
<td/>
</tr>
<tr>
<td>Maximum quantity</td>
<td>Interior/exterior</td>
<td>Is the maximum number of materials that firms need to order</td>
<td/>
</tr>
<tr>
<td>Quantity in purchase requisition</td>
<td>Interior/exterior</td>
<td>Are the firm&#x2019;s requests that are needed to make an order</td>
<td/>
</tr>
<tr>
<td>Risk labels</td>
<td>Interior/exterior</td>
<td>Is any attribute that may raise the uncertainty of risk occurrence</td>
<td/>
</tr>
<tr>
<td>Products</td>
<td>Interior/exterior</td>
<td>Is the final product for sale</td>
<td/>
</tr>
<tr>
<td>Location</td>
<td>Interior/exterior</td>
<td>Is the local or international venue where firms receive or dispatch their orders</td>
<td/>
</tr>
</tbody>
</table>
</table-wrap>
</sec>
<sec id="s3_2">
<label>3.2</label>
<title>Big Data Collection Process</title>
<p>Big data collection from different KSA firms was performed, and the data was pre-processed to make it more meaningful for the proposed technique, as depicted in <xref ref-type="fig" rid="fig-4">Fig. 4</xref>. The first step is categorized into two stages. The first stage involved gathering information from SLAs, including the products&#x2019; features and supply chain 4.0 attributes. The second stage linked the labels to the data&#x2019;s features and attributes by the firms&#x2019; chief executive officer (CEO), as shown in <xref ref-type="table" rid="table-1">Tab. 1</xref>. According to these features&#x2019; values, the CEOs can manually identify the potential risks that the company faces. The next step logged the data into the Structured Query Language (SQL) format to read the data to identify the risk labels and then sort them into Object Linking and Embedding, Database (Ole DB). The tested dataset in this work comprised nine risk labels. To automatically define the firms&#x2019; risks, the relationships between risk labels and their attributes are identified by the proposed voting classifier based on the SCDG optimization algorithm.</p>
</sec>
<sec id="s3_3">
<label>3.3</label>
<title>Sine Cosine Algorithm</title>
<p>The basic Sine Cosine Algorithm (SCA) was first proposed in [<xref ref-type="bibr" rid="ref-47">47</xref>] for optimization problems. The algorithm was based initially on the sine and cosine oscillation functions for updating the candidate solutions&#x2019; position. SCA uses a set of random variables to indicate the movement direction and how far the movement should be in order to emphasize/deemphasize the effect of the destination and to switch between the cosine and sine components. SCA uses the following mathematical form for updating the positions of different solutions:</p>
<p><disp-formula id="eqn-1">
<label>(1)</label>
<!--<tex-math id="tex-eqn-1"><![CDATA[$$\begin{equation}
X_{i}^{t+1}=\begin{cases}X_{i}^{t}+r_{1}\times \sin \left(r_{2}\right)\times \left| r_{3}P_{i}^{t}-X_{i}^{t}\right| r_{4}< 0.5 \\ X_{i}^{t}+r_{1}\times \cos \left(r_{2}\right)\times \left| r_{3}P_{i}^{t}-X_{i}^{t}\right| r_{4} \geq 0.5 \end{cases}
 \label{eqn-1}
\end{equation}$$]]></tex-math>-->
<mml:math id="mml-eqn-1" display="block"><mml:msubsup><mml:mrow><mml:mi>X</mml:mi></mml:mrow><mml:mrow><mml:mi>i</mml:mi></mml:mrow><mml:mrow><mml:mi>t</mml:mi><mml:mo lspace='0pt' rspace='0pt'>+</mml:mo><mml:mn>1</mml:mn></mml:mrow></mml:msubsup><mml:mo>=</mml:mo><mml:mrow><mml:mrow><mml:mo>{</mml:mo><mml:mrow><mml:mtable equalrows="false" columnlines="none" equalcolumns="false"><mml:mtr><mml:mtd columnalign="left"><mml:msubsup><mml:mrow><mml:mi>X</mml:mi></mml:mrow><mml:mrow><mml:mi>i</mml:mi></mml:mrow><mml:mrow><mml:mi>t</mml:mi></mml:mrow></mml:msubsup><mml:mo>+</mml:mo><mml:msub><mml:mrow><mml:mi>r</mml:mi></mml:mrow><mml:mrow><mml:mn>1</mml:mn></mml:mrow></mml:msub><mml:mo>&#x00D7;</mml:mo><mml:mo> sin</mml:mo><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:msub><mml:mrow><mml:mi>r</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mo>)</mml:mo></mml:mrow><mml:mo>&#x00D7;</mml:mo><mml:mrow><mml:mo>|</mml:mo><mml:mrow><mml:msub><mml:mrow><mml:mi>r</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub><mml:msubsup><mml:mrow><mml:mi>P</mml:mi></mml:mrow><mml:mrow><mml:mi>i</mml:mi></mml:mrow><mml:mrow><mml:mi>t</mml:mi></mml:mrow></mml:msubsup><mml:mo>-</mml:mo><mml:msubsup><mml:mrow><mml:mi>X</mml:mi></mml:mrow><mml:mrow><mml:mi>i</mml:mi></mml:mrow><mml:mrow><mml:mi>t</mml:mi></mml:mrow></mml:msubsup></mml:mrow><mml:mo>|</mml:mo></mml:mrow><mml:msub><mml:mrow><mml:mi>r</mml:mi></mml:mrow><mml:mrow><mml:mn>4</mml:mn></mml:mrow></mml:msub><mml:mo>&#x003C;</mml:mo><mml:mn>0</mml:mn><mml:mo>.</mml:mo><mml:mn>5</mml:mn><mml:mspace width="1em"/></mml:mtd></mml:mtr><mml:mtr><mml:mtd columnalign="left"><mml:msubsup><mml:mrow><mml:mi>X</mml:mi></mml:mrow><mml:mrow><mml:mi>i</mml:mi></mml:mrow><mml:mrow><mml:mi>t</mml:mi></mml:mrow></mml:msubsup><mml:mo>+</mml:mo><mml:msub><mml:mrow><mml:mi>r</mml:mi></mml:mrow><mml:mrow><mml:mn>1</mml:mn></mml:mrow></mml:msub><mml:mo>&#x00D7;</mml:mo><mml:mo> cos</mml:mo><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:msub><mml:mrow><mml:mi>r</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mo>)</mml:mo></mml:mrow><mml:mo>&#x00D7;</mml:mo><mml:mrow><mml:mo>|</mml:mo><mml:mrow><mml:msub><mml:mrow><mml:mi>r</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub><mml:msubsup><mml:mrow><mml:mi>P</mml:mi></mml:mrow><mml:mrow><mml:mi>i</mml:mi></mml:mrow><mml:mrow><mml:mi>t</mml:mi></mml:mrow></mml:msubsup><mml:mo>-</mml:mo><mml:msubsup><mml:mrow><mml:mi>X</mml:mi></mml:mrow><mml:mrow><mml:mi>i</mml:mi></mml:mrow><mml:mrow><mml:mi>t</mml:mi></mml:mrow></mml:msubsup></mml:mrow><mml:mo>|</mml:mo></mml:mrow><mml:msub><mml:mrow><mml:mi>r</mml:mi></mml:mrow><mml:mrow><mml:mn>4</mml:mn></mml:mrow></mml:msub><mml:mo>&#x2265;</mml:mo><mml:mn>0</mml:mn><mml:mo>.</mml:mo><mml:mn>5</mml:mn><mml:mspace width="1em"/></mml:mtd></mml:mtr> </mml:mtable></mml:mrow><mml:mo></mml:mo></mml:mrow></mml:mrow></mml:math></disp-formula></p>

<fig id="fig-3">
<label>Figure 3</label>
<caption>
<title>Internal and external risk events of supply chain 4.0</title>
</caption>
<graphic mimetype="image" mime-subtype="png" xlink:href="CMC_18179-fig-3.png"/>
</fig>
<fig id="fig-4">
<label>Figure 4</label>
<caption>
<title>Pre-processing big data gathered from different KSA firms</title>
</caption>
<graphic mimetype="image" mime-subtype="png" xlink:href="CMC_18179-fig-4.png"/>
</fig>
<p>where <italic>Xit</italic> is the current solution position in the <italic>ith</italic> dimension, and <italic>Pit</italic> represents the best solution in the <italic>ith</italic> dimension. The parameters <italic>r</italic><sub>2</sub>, <italic>r</italic><sub>3</sub>, and <italic>r</italic><sub>4</sub> are random values in [0,1]. <xref ref-type="disp-formula" rid="eqn-1">Eq. 1</xref> shows that the agents&#x2019; positions are updated using the position of the best solution. To achieve a balance between the exploitation and exploration processes in the SCA algorithm, parameter <italic>r</italic><sub>1</sub> can be updated during iterations as:</p>
<p><disp-formula id="eqn-2">
<label>(2)</label>
<!--<tex-math id="tex-eqn-2"><![CDATA[$$\begin{equation}
r_{1}=a-\frac{a\times t}{t_{max}}
 \label{eqn-2}
\end{equation}$$]]></tex-math>-->
<mml:math id="mml-eqn-2" display="block"><mml:msub><mml:mrow><mml:mi>r</mml:mi></mml:mrow><mml:mrow><mml:mn>1</mml:mn></mml:mrow></mml:msub><mml:mo>=</mml:mo><mml:mi>a</mml:mi><mml:mo>-</mml:mo><mml:mfrac><mml:mrow><mml:mi>a</mml:mi><mml:mo>&#x00D7;</mml:mo><mml:mi>t</mml:mi></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi>t</mml:mi></mml:mrow><mml:mrow><mml:mi>m</mml:mi><mml:mi>a</mml:mi><mml:mi>x</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:mfrac></mml:math></disp-formula></p>
<p>where <italic>t</italic> represents the current iteration; <italic>a</italic> is a constant; and <italic>t<sub>max</sub></italic> is the maximum number of iterations.</p>
<p>The initial population positions with <italic>n</italic> agents in the SCA algorithm are randomly set up as shown in Algorithm (1). The objective function is computed in Step 5 for all agents to find the best solution&#x2019;s position. <italic>P</italic> in Step 6 indicates the best solution. Parameter <italic>r</italic><sub>1</sub> is updated according to <xref ref-type="disp-formula" rid="eqn-2">Eq. (2)</xref> in Step 7. The positions of different agents are updated by <xref ref-type="disp-formula" rid="eqn-1">Eq. (1)</xref> in Steps 8&#x2013;13. Steps 4&#x2013;16 are repeated according to the number of iterations. The best solution is updated until the end of the iteration.</p>
<p>The original SCA algorithm shows high exploitation of the search space compared to a wide range of other meta-heuristics owing to its use of a single best solution to guide other candidate solutions. This makes the algorithm efficient in terms of memory usage and convergence speed. However, this algorithm may show slightly lower performance in problems with many locally optimal solutions. This motivated our attempt to overcome this drawback in the proposed Sine Cosine Dynamic Group algorithm.</p>
<fig id="fig-10">
<graphic mimetype="image" mime-subtype="png" xlink:href="CMC_18179-inline-1.png"/>
</fig>
</sec>
</sec>
<sec id="s4">
<label>4</label>
<title>Proposed Sine Cosine Dynamic Group Algorithm</title>
<p>The proposed optimization technique in this work is called the SCDG algorithm. The SCDG algorithm can be employed for risk identification in supply chain 4.0 based on an ensemble model. The SCDG algorithm starts by randomly generating several individuals, as shown in Algorithm (2). Each individual indicates a solution that can be a candidate solution to the supply chain 4.0 problem. After calculating the objective function <italic>F<sub>n</sub></italic> for each agent <italic>X<sub>i</sub></italic>, the best solution is selected and indicated as <italic>P</italic>.</p>
<p>The Dynamic Groups behavior of the SCDG algorithm divides all the individuals into an exploration group (<italic>n</italic><sub>1</sub>) and an exploitation group (<italic>n</italic><sub>2</sub>). The number of solutions in each group is managed dynamically with each iteration according to the best solution. The exploration group processes with <italic>n</italic><sub>1</sub> agents, and the exploitation group with <italic>n</italic><sub>2</sub> agents, as shown in <xref ref-type="fig" rid="fig-5">Fig. 5</xref>. SCDG initiates the groups with 50% exploration and 50% exploitation. Then, the number of agents in the exploration group (<italic>n</italic><sub>1</sub>) is decreased, and the number of agents in the exploitation group (<italic>n</italic><sub>2</sub>) is increased.</p>
<fig id="fig-11">
<graphic mimetype="image" mime-subtype="png" xlink:href="CMC_18179-inline-2.png"/>
</fig>
<p>However, suppose the best solution&#x2019;s objective function value did not change for three continuous iterations. In that case, the algorithm starts to increase the number of agents in the exploration group (<italic>n</italic>1) to get another best solution and hopefully avoid local optima. <xref ref-type="fig" rid="fig-6">Fig. 6</xref> shows the balancing between exploration and exploitation in the proposed SCDG algorithm during iterations. SCDG uses the Sine Cosine <xref ref-type="disp-formula" rid="eqn-1">Eq. (1)</xref> for updating the positions of the exploration group (<italic>n</italic><sub>1</sub>) and the exploitation group (<italic>n</italic><sub>2</sub>). Parameter <italic>r</italic><sub>1</sub> is updated during iterations as <inline-formula id="ieqn-1"><mml:math id="mml-ieqn-1"><mml:msub><mml:mrow><mml:mi>r</mml:mi></mml:mrow><mml:mrow><mml:mn>1</mml:mn></mml:mrow></mml:msub><mml:mo>=</mml:mo><mml:mi>a</mml:mi><mml:mo>-</mml:mo><mml:mfrac><mml:mrow><mml:mi>a</mml:mi><mml:mo>&#x00D7;</mml:mo><mml:mi>t</mml:mi></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi>t</mml:mi></mml:mrow><mml:mrow><mml:mi>m</mml:mi><mml:mi>a</mml:mi><mml:mi>x</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:mfrac></mml:math></inline-formula>, where <italic>t</italic> is the current iteration; <italic>a</italic> is a constant; and <italic>t<sub>max</sub></italic> is the number of iterations. At the end of each iteration, SCDG updates the agents in the search space, and the agent&#x2019;s order is randomly changed to exchange the agents&#x2019; roles in the exploration and exploitation groups. In the final step, SCDG returns the best solution.</p>
</sec>
<sec id="s5">
<label>5</label>
<title>Experimental Results</title>
<p>This section details three different experiments and statistical tests that were conducted to verify the accuracy of the proposed algorithm. In the first experiment, Support Vector Machine (SVM) [<xref ref-type="bibr" rid="ref-48">48</xref>], Neural Network (NN) [<xref ref-type="bibr" rid="ref-49">49</xref>], k-Nearest Neighbor (KNN) [<xref ref-type="bibr" rid="ref-50">50</xref>], and Random Forest [<xref ref-type="bibr" rid="ref-51">51</xref>] classifiers were applied to identify the operational risks in the supply chain 4.0. The second experiment was designed to compare the proposed SCDG-based voting classifier with the bagging and majority voting ensemble techniques. The last experiment compared the proposed voting SCDG algorithm with Particle Swarm Optimization (PSO) [<xref ref-type="bibr" rid="ref-17">17</xref>], Whale Optimization Algorithm (WOA) [<xref ref-type="bibr" rid="ref-19">19</xref>], Grey Wolf Optimizer (GWO) [<xref ref-type="bibr" rid="ref-21">21</xref>], and the Genetic Algorithm (GA)-based [<xref ref-type="bibr" rid="ref-23">23</xref>] voting classifier algorithms to test the algorithm&#x2019;s effectiveness. The ANOVA and Wilcoxon&#x2019;s rank-sum statistical tests were performed to verify the efficacy of the proposed SCDG algorithm. <xref ref-type="table" rid="table-2">Tab. 2</xref> lists the configurations of the proposed SCDG algorithm and the other algorithms used in the experiments.</p>
<fig id="fig-5">
<label>Figure 5</label>
<caption>
<title>The proposed SCDG algorithm&#x2019;s exploration and exploitation processes. (a) Exploration group, (b) Exploitation group</title>
</caption>
<graphic mimetype="image" mime-subtype="png" xlink:href="CMC_18179-fig-5.png"/>
</fig>
<sec id="s5_1">
<label>5.1</label>
<title>Metrics of Performance Evaluation</title>
<p>The AUC (area under the ROC curve) and MSE (Mean Square Error) metrics were employed in this experiment as performance metrics. AUC or balanced accuracy indicates the classification performance independently between class distribution [<xref ref-type="bibr" rid="ref-20">20</xref>]. For binary classification, AUC can be directly calculated as the average of sensitivity and specificity, resulting in binary predictions rather than scores. The balanced accuracy or AUC value is mathematically expressed as:</p>
<p><disp-formula id="eqn-3">
<label>(3)</label>
<!--<tex-math id="tex-eqn-3"><![CDATA[$$\begin{equation}
AUC=(\mathit{Specificity}+\mathit{Sensitivity})/2
 \label{eqn-3}
\end{equation}$$]]></tex-math>-->
<mml:math id="mml-eqn-3" display="block"><mml:mi>A</mml:mi><mml:mi>U</mml:mi><mml:mi>C</mml:mi><mml:mo>=</mml:mo><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:mstyle mathvariant="italic"><mml:mi>S</mml:mi><mml:mi>p</mml:mi><mml:mi>e</mml:mi><mml:mi>c</mml:mi><mml:mi>i</mml:mi><mml:mi>fi</mml:mi><mml:mi>c</mml:mi><mml:mi>i</mml:mi><mml:mi>t</mml:mi><mml:mi>y</mml:mi></mml:mstyle><mml:mo>+</mml:mo><mml:mstyle mathvariant="italic"><mml:mi>S</mml:mi><mml:mi>e</mml:mi><mml:mi>n</mml:mi><mml:mi>s</mml:mi><mml:mi>i</mml:mi><mml:mi>t</mml:mi><mml:mi>i</mml:mi><mml:mi>v</mml:mi><mml:mi>i</mml:mi><mml:mi>t</mml:mi><mml:mi>y</mml:mi></mml:mstyle></mml:mrow><mml:mo>)</mml:mo></mml:mrow><mml:mo>/</mml:mo><mml:mn>2</mml:mn></mml:math></disp-formula></p>

<fig id="fig-6">
<label>Figure 6</label>
<caption>
<title>Balancing between exploitation and exploration in the proposed SCDG algorithm</title>
</caption>
<graphic mimetype="image" mime-subtype="png" xlink:href="CMC_18179-fig-6.png"/>
</fig>

<table-wrap id="table-2">
<label>Table 2</label>
<caption>
<title>Configuration of the proposed SCDG and the compared algorithms</title>
</caption>
<table>
<colgroup>
<col/>
</colgroup>
<tbody>
<tr>
<td><graphic mimetype="image" mime-subtype="png" xlink:href="CMC_18179-inline-3.png"/></td>
</tr>
</tbody>
</table>
</table-wrap>
<p>Mean Square Error or MSE indicates the performance of the classifiers. The MSE value is mainly based on the difference between the actual and the required value of the classifier&#x2019; output using the following form:</p>
<p><disp-formula id="eqn-4">
<label>(4)</label>
<!--<tex-math id="tex-eqn-4"><![CDATA[$$\begin{equation}
MSE=\sum_{x=1}^{n}(o_{x}^{h}d_{x}^{h})^{2}
 \label{eqn-4}
\end{equation}$$]]></tex-math>-->
<mml:math id="mml-eqn-4" display="block"><mml:mi>M</mml:mi><mml:mi>S</mml:mi><mml:mi>E</mml:mi><mml:mo>=</mml:mo><mml:mstyle displaystyle='true'><mml:mstyle displaystyle='true'><mml:munderover><mml:mrow><mml:mo>&#x2211;</mml:mo> </mml:mrow><mml:mrow><mml:mi>x</mml:mi><mml:mo lspace='0pt' rspace='0pt'>=</mml:mo><mml:mn>1</mml:mn></mml:mrow><mml:mrow><mml:mi>n</mml:mi></mml:mrow></mml:munderover></mml:mstyle></mml:mstyle><mml:msup><mml:mrow><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:msubsup><mml:mrow><mml:mi>o</mml:mi></mml:mrow><mml:mrow><mml:mi>x</mml:mi></mml:mrow><mml:mrow><mml:mi>h</mml:mi></mml:mrow></mml:msubsup><mml:msubsup><mml:mrow><mml:mi>d</mml:mi></mml:mrow><mml:mrow><mml:mi>x</mml:mi></mml:mrow><mml:mrow><mml:mi>h</mml:mi></mml:mrow></mml:msubsup></mml:mrow><mml:mo>)</mml:mo></mml:mrow></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msup></mml:math></disp-formula></p>
<p>where <italic>n</italic> is the number of outputs when the <inline-formula id="ieqn-2"><mml:math id="mml-ieqn-2"><mml:msup><mml:mrow><mml:mi>h</mml:mi></mml:mrow><mml:mrow><mml:mstyle class="text"><mml:mtext class="textit" mathvariant="italic">th</mml:mtext></mml:mstyle></mml:mrow></mml:msup></mml:math></inline-formula> training instance is applied, and <italic>d<inline-formula id="ieqn-3"><mml:math id="mml-ieqn-3"><mml:msubsup><mml:mrow></mml:mrow><mml:mrow><mml:mi>x</mml:mi></mml:mrow><mml:mrow><mml:mi>t</mml:mi><mml:mi>h</mml:mi></mml:mrow></mml:msubsup></mml:math></inline-formula></italic> is the <italic>x<sup><italic>th</italic></sup></italic> optimal output of the input neuron. When the <italic>h</italic><sup><italic>th</italic></sup> training instance appears in the input, <italic>oh<sub><italic>x</italic></sub></italic> is the actual output of the <italic>x</italic><sup><italic>th</italic></sup> input neuron.</p>
</sec>
<sec id="s5_2">
<label>5.2</label>
<title>Results</title>
<p>In the first experiment, the output results for the single classifiers SVM, NN, KNN, and Random Forest (RF) are shown in <xref ref-type="table" rid="table-3">Tab. 3</xref>. As the table shows, the single classifier of Random Forest achieved the AUC percentage of 0.823, which was the highest value among single classifiers, with the minimum MSE being 0.042853. However, this is not an acceptable percentage and can be improved based on ensemble techniques. The second experiment&#x2019;s results comparing the proposed SCDG voting classifier with the bagging and majority-based ensemble learning methods are shown in <xref ref-type="table" rid="table-4">Tab. 4</xref>. The proposed SCDG-based voting classifier achieved an AUC result of 0.989, which was much better than the compared ensemble techniques and the single classifiers. The MSE of the SCDG algorithm-based voting classifier (3.30E-06) was much better than the MSE of the bagging (0.0476) and the majority voting (0.007921) techniques.</p>
<p>The SCDG voting classifier was compared in the third experiment with the voting classifiers based on PSO, WOA, GWO, and GA, and the output results are mentioned in <xref ref-type="table" rid="table-5">Tab. 5</xref>. The results show the superiority of the proposed SCDG voting classifier, with an AUC of 0.989 and MSE of 3.30E-06 compared to the voting PSO (AUC = 0.931), voting WOA (AUC = 0.913), voting GWO (AUC = 0.925), and voting GA (AUC = 0.872). To show the proposed SCDG optimization algorithm&#x2019;s performance versus other optimization algorithms of PSO, WOA, GWO, and GA, <xref ref-type="fig" rid="fig-7">Fig. 7</xref> shows the algorithms&#x2019; convergence curves.</p>
<table-wrap id="table-3">
<label>Table 3</label>
<caption>
<title>Single classifiers&#x2019; AUC and MSE</title>
</caption>
<table>
<colgroup>
<col/>
<col/>
<col/>
<col/>
<col/>
</colgroup>
<thead>
<tr>
<th></th>
<th>SVM</th>
<th>NN</th>
<th>KNN</th>
<th>Random forest</th>
</tr>
</thead>
<tbody>
<tr>
<td>AUC</td>
<td>0.784</td>
<td>0.713</td>
<td>0.761</td>
<td>0.823</td>
</tr>
<tr>
<td>MSE</td>
<td>0.099845</td>
<td>0.082373</td>
<td>0.114932</td>
<td>0.042853</td>
</tr>
</tbody>
</table>
</table-wrap>
 
<table-wrap id="table-4">
<label>Table 4</label>
<caption>
<title>Proposed SCDG-based voting classifier compared to other ensemble techniques</title>
</caption>
<table>
<colgroup>
<col/>
<col/>
<col/>
<col/>
</colgroup>
<thead>
<tr>
<th></th>
<th>Bagging</th>
<th>Majority voting</th>
<th>Voting (SCDG)</th>
</tr>
</thead>
<tbody>
<tr>
<td>AUC</td>
<td>0.842</td>
<td>0.924</td>
<td>0.989</td>
</tr>
<tr>
<td>MSE</td>
<td>0.0476</td>
<td>0.007921</td>
<td>3.30E-06</td>
</tr>
</tbody>
</table>
</table-wrap>
<p>As seen from the results, the proposed algorithm obtains a better solution in minimum time. To confirm the proposed SCDG voting classifier&#x2019;s effectiveness with other voting classifiers based on PSO, WOA, GWO, and GA algorithms through visualization, <xref ref-type="fig" rid="fig-8">Fig. 8</xref> shows the respective ROCs. <xref ref-type="table" rid="table-6">Tab. 6</xref> lists the results for this curve. As shown from the output results in <xref ref-type="table" rid="table-6">Tab. 6</xref>, the proposed SCDG classifier achieved an area under the curve of about 1.0. Therefore, the proposed classifier has a performance that can distinguish the data in supply chain 4.0 with a high AUC.</p>
<table-wrap id="table-5">
<label>Table 5</label>
<caption>
<title>Proposed SCDG-based voting classifier compared to other voting-based algorithms</title>
</caption>
<table>
<colgroup>
<col/>
<col/>
<col/>
<col/>
<col/>
<col/>
</colgroup>
<thead>
<tr>
<th></th>
<th>Voting (SCDG)</th>
<th>Voting (PSO)</th>
<th>Voting (WOA)</th>
<th>Voting (GWO)</th>
<th>Voting (GA)</th>
</tr>
</thead>
<tbody>
<tr>
<td>AUC</td>
<td>0.989</td>
<td>0.931</td>
<td>0.913</td>
<td>0.925</td>
<td>0.872</td>
</tr>
<tr>
<td>MSE</td>
<td>3.30E-06</td>
<td>0.00251</td>
<td>0.00918</td>
<td>0.00425</td>
<td>0.016721</td>
</tr>
</tbody>
</table>
</table-wrap>
<fig id="fig-7">
<label>Figure 7</label>
<caption>
<title>Convergence curve of the proposed SCDG algorithm <italic>vs.</italic> compared optimization algorithms</title>
</caption>
<graphic mimetype="image" mime-subtype="png" xlink:href="CMC_18179-fig-7.png"/>
</fig>
</sec>
<sec id="s5_3">
<label>5.3</label>
<title>Statistical Analysis</title>
<p>The ANOVA test was first applied to identify the statistical difference between the MSE of the proposed SCDG voting classifier and other compared classifiers. Two hypotheses, the null hypothesis and alternate hypothesis, were formulated. The null hypothesis was (<italic><inline-graphic xlink:href="CMC_18179-inline-4.png"/> <inline-graphic xlink:href="CMC_18179-inline-5.png"/></italic>), and the alternate hypothesis was (<italic>H</italic><sub>1</sub>: non-equal means). <xref ref-type="table" rid="table-7">Tab. 7</xref> shows the descriptive statistics of the data. The results of the ANOVA test are provided in <xref ref-type="table" rid="table-8">Tab. 8</xref>. <xref ref-type="fig" rid="fig-8">Fig. 8</xref> also shows the ANOVA test results based on the proposed voting SCDG classifier&#x2019;s objective function and the compared classifiers. The results show that the alternate hypothesis <italic>H</italic><sub>1</sub> was accepted.</p>
<p>Wilcoxon&#x2019;s rank-sum test was then employed to obtain the p-values between the proposed SCDG voting classifier and other classifiers. The main aim of this test was to determine whether the results of the proposed SCDG voting classifier and different classifiers had a significant difference. p-value &#x003C; 0.05 means significant superiority of the SCDG classifier. If the p-value <italic>&#x00BF;</italic> 0.05, it means that there is no significant difference. Two hypotheses, the null hypothesis and alternate hypothesis, were formulated for this test also. The null hypothesis was <italic><inline-graphic xlink:href="CMC_18179-inline-6.png"/> <inline-graphic xlink:href="CMC_18179-inline-7.png"/></italic>, and the alternate hypothesis was (<italic>H</italic><sub>1</sub>: non-equal means). The p-value results are presented in <xref ref-type="table" rid="table-9">Tab. 9</xref>. The p-values were less than 0.05. This was achieved for the results between the proposed SCDG classifier and other classifiers. The results showed superiority of the proposed classifier and the statistical significance of the classifier. The alternate hypothesis <italic>H</italic><sub>1</sub> was accepted.</p>
<fig id="fig-8">
<label>Figure 8</label>
<caption>
<title>SCDG voting classifier <italic>vs.</italic> other voting classifiers</title>
</caption>
<graphic mimetype="image" mime-subtype="png" xlink:href="CMC_18179-fig-8.png"/>
</fig>
 
<table-wrap id="table-6">
<label>Table 6</label>
<caption>
<title>ROC curve data of SCDG voting classifier <italic>vs.</italic> other voting classifiers</title>
</caption>
<table>
<colgroup>
<col/>
<col/>
<col/>
<col/>
<col/>
</colgroup>
<thead>
<tr>
<th></th>
<th>Voting (SCDG): Voting (PSO)</th>
<th>Voting (SCDG): Voting (WOA)</th>
<th>Voting (SCDG): Voting (GWO)</th>
<th>Voting (SCDG): Voting (GA)</th>
</tr>
</thead>
<tbody>
<tr>
<td>Area</td>
<td>1</td>
<td>1</td>
<td>1</td>
<td>1</td>
</tr>
<tr>
<td>Std. Error</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
</tr>
<tr>
<td>95% confidence interval</td>
<td>1.000 to 1.000</td>
<td>1.000 to 1.000</td>
<td>1.000 to 1.000</td>
<td>1.000 to 1.000</td>
</tr>
<tr>
<td>P value</td>
<td>0.0001</td>
<td>0.0001</td>
<td>0.0001</td>
<td>0.0001</td>
</tr>
</tbody>
</table>
</table-wrap>
</sec>
<sec id="s5_4">
<label>5.4</label>
<title>Residuals <italic>vs.</italic> Fits Plot</title>
<p>The possible issues could be observed from the recurring values as well as the residual plots as opposed to the original dataset plot. Some datasets are not good for classification. The ideal situation is attained if the residual values are equally randomly spaced around the horizontal axis. The residual value is calculated as (Real value - Predicted value), with the mean and sum of the residuals equal to zero. <xref ref-type="fig" rid="fig-9">Fig. 9</xref> shows the residual plot. The heteroscedasticity plot, also shown in <xref ref-type="fig" rid="fig-9">Fig. 9</xref>, can help discover violations of assumptions, thus boosting the credibility of the research study&#x2019;s findings.</p>
<p>Homoscedasticity describes a situation in which the error term (arbitrary disturbance in the connection between the dependent variable and the independent variables, or noise) is the same throughout the independent variables&#x2019; values. The quantile-quantile (QQ) plot, shown in <xref ref-type="fig" rid="fig-9">Fig. 9</xref>, is known as a chance plot. It is mostly used by plotting the quantiles and comparing them to contrast two probability distributions. As the figure shows, the points&#x2019; distributions in the QQ approximately fit the line. Therefore, the actual and the forecasted residuals were linearly related, thus validating the recommended SCDG ballot classifier&#x2019;s efficiency in identifying operational threats in the supply chain 4.0.</p>
<table-wrap id="table-7">
<label>Table 7</label>
<caption>
<title>Descriptive statistics of data</title>
</caption>
<table>
<colgroup>
<col/>
<col/>
<col/>
<col/>
<col/>
<col/>
</colgroup>
<thead>
<tr>
<th></th>
<th>Voting (SCDG)</th>
<th>Voting (PSO)</th>
<th>Voting (WOA)</th>
<th>Voting (GWO)</th>
<th>Voting GA)</th>
</tr>
</thead>
<tbody>
<tr>
<td>Number of values</td>
<td>20</td>
<td>20</td>
<td>20</td>
<td>20</td>
<td>20</td>
</tr>
<tr>
<td>Mean</td>
<td>0.0000033</td>
<td>0.006525</td>
<td>0.004963</td>
<td>0.004572</td>
<td>0.002406</td>
</tr>
<tr>
<td>Std. Deviation</td>
<td>0</td>
<td>0.002004</td>
<td>0.003645</td>
<td>0.002573</td>
<td>0.00114</td>
</tr>
<tr>
<td>Std. Error of Mean</td>
<td>0</td>
<td>0.0004482</td>
<td>0.000815</td>
<td>0.0005754</td>
<td>0.0002549</td>
</tr>
</tbody>
</table>
</table-wrap>
 
<table-wrap id="table-8">
<label>Table 8</label>
<caption>
<title>ANOVA test results of SCDG voting classifier <italic>vs.</italic> other voting classifiers</title>
</caption>
<table>
<colgroup>
<col/>
<col/>
<col/>
<col/>
<col/>
<col/>
</colgroup>
<thead>
<tr>
<th></th>
<th>SS</th>
<th>DF</th>
<th>MS</th>
<th>F (DFn, DFd)</th>
<th>P-value</th>
</tr>
</thead>
<tbody>
<tr>
<td>Treatment (between columns)</td>
<td>0.000514</td>
<td>4</td>
<td>0.000128</td>
<td>F (4, 95) = 25.45</td>
<td>P &#x003C; 0.0001</td>
</tr>
<tr>
<td>Residual (within columns)</td>
<td>0.000479</td>
<td>95</td>
<td>5.04E-06</td>
<td>&#x2013;</td>
<td>&#x2013;</td>
</tr>
<tr>
<td>Total</td>
<td>0.000993</td>
<td>99</td>
<td>&#x2013;</td>
<td>&#x2013;</td>
<td>&#x2013;</td>
</tr>
</tbody>
</table>
</table-wrap>
 
<table-wrap id="table-9">
<label>Table 9</label>
<caption>
<title>Wilcoxon rank-sum test results of SCDG voting classifier <italic>vs.</italic> other voting classifiers</title>
</caption>
<table>
<colgroup>
<col/>
<col/>
<col/>
<col/>
<col/>
<col/>
<col/>
</colgroup>
<thead>
<tr>
<th></th>
<th>Voting</th>
<th>Voting</th>
<th>Voting</th>
<th>Voting</th>
<th>Voting</th>
</tr>
<tr>
<th></th>
<th>(SCDG)</th>
<th>(PSO)</th>
<th>(WOA)</th>
<th>(GWO)</th>
<th>GA)</th>
</tr>
</thead>
<tbody>
<tr>
<td>Theoretical median</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
</tr>
<tr>
<td>Actual median</td>
<td>0.0000033</td>
<td>0.006174</td>
<td>0.005105</td>
<td>0.004533</td>
<td>0.002936</td>
</tr>
<tr>
<td>Number of values</td>
<td>20</td>
<td>20</td>
<td>20</td>
<td>20</td>
<td>20</td>
</tr>
<tr>
<td>Wilcoxon Signed-Rank</td>
<td>210</td>
<td>210</td>
<td>210</td>
<td>210</td>
<td>210</td>
</tr>
<tr>
<td>Test Sum of signed</td>
<td/>
</tr>
<tr>
<td>ranks (W)</td>
<td/>
</tr>
<tr>
<td>Sum of positive ranks</td>
<td>210</td>
<td>210</td>
<td>210</td>
<td>210</td>
<td>210</td>
</tr>
<tr>
<td>Sum of negative ranks</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
<td>0</td>
</tr>
<tr>
<td>P-value (two-tailed)</td>
<td>0.0001</td>
<td>0.0001</td>
<td>0.0001</td>
<td>0.0001</td>
<td>0.0001</td>
</tr>
<tr>
<td>Exact or estimate?</td>
<td>Exact</td>
<td>Exact</td>
<td>Exact</td>
<td>Exact</td>
<td>Exact</td>
</tr>
<tr>
<td>P-value summary</td>
<td><inline-formula id="ieqn-4"><mml:math id="mml-ieqn-4"><mml:mo>*</mml:mo><mml:mo>*</mml:mo><mml:mo>*</mml:mo><mml:mo>*</mml:mo></mml:math></inline-formula></td>
<td><inline-formula id="ieqn-5"><mml:math id="mml-ieqn-5"><mml:mo>*</mml:mo><mml:mo>*</mml:mo><mml:mo>*</mml:mo><mml:mo>*</mml:mo></mml:math></inline-formula></td>
<td><inline-formula id="ieqn-6"><mml:math id="mml-ieqn-6"><mml:mo>*</mml:mo><mml:mo>*</mml:mo><mml:mo>*</mml:mo><mml:mo>*</mml:mo></mml:math></inline-formula></td>
<td><inline-formula id="ieqn-7"><mml:math id="mml-ieqn-7"><mml:mo>*</mml:mo><mml:mo>*</mml:mo><mml:mo>*</mml:mo><mml:mo>*</mml:mo></mml:math></inline-formula></td>
<td><inline-formula id="ieqn-8"><mml:math id="mml-ieqn-8"><mml:mo>*</mml:mo><mml:mo>*</mml:mo><mml:mo>*</mml:mo><mml:mo>*</mml:mo></mml:math></inline-formula></td>
</tr>
<tr>
<td>Significant</td>
<td>Yes</td>
<td>Yes</td>
<td>Yes</td>
<td>Yes</td>
<td>Yes</td>
</tr>
<tr>
<td>(alpha = 0.05)?</td>
<td/>
</tr>
<tr>
<td>How big is the</td>
<td>0.0000033</td>
<td>0.006174</td>
<td>0.005105</td>
<td>0.004533</td>
<td>0.002936</td>
</tr>
<tr>
<td>discrepancy? Discrepancy</td>
<td/>
</tr>
</tbody>
</table>
</table-wrap>
<fig id="fig-9">
<label>Figure 9</label>
<caption>
<title>Residuals <italic>vs.</italic> Fits Plot</title>
</caption>
<graphic mimetype="image" mime-subtype="png" xlink:href="CMC_18179-fig-9.png"/>
</fig>
</sec>
</sec>
<sec id="s6">
<label>6</label>
<title>Conclusion</title>
<p>Supply chain management systems&#x2019; fourth revolution, called supply chain 4.0, integrates the manufacturing operations of the supply chain, telecommunication, and information technology processes. Supply chain 4.0 aims to improve supply chains&#x2019; production systems and profitability; however, it suffers from different operational and disruptive risks. A voting classifier based on a proposed optimization algorithm is proposed in this paper to identify the operational risks in the supply chain 4.0. The Sine Cosine Dynamic Group (SCDG) algorithm is proposed. The mechanisms of exploitation and exploration of the original Sine Cosine Algorithm (CSA) are adjusted by dynamic groups that are updated based on some conditions during the iterations. External and internal features were collected and analyzed from different data sources of service level agreements (SLAs) and various KSA firms&#x2019; transaction data to validate the proposed algorithm&#x2019;s efficiency. A high balanced accuracy or AUC and a Minimum Mean Square Error (MSE) were achieved compared with other optimization-based classifiers. The ANOVA and Wilcoxon-rank-sum tests were performed, which showed the superiority of the proposed SCDG voting classifier. Thus, the experimental results indicate the effectiveness of the proposed SCDG algorithm-based voting classifier.</p>
</sec>
</body>
<back>
<ack><p>We thank LetPub (<uri xlink:href="https://www.letpub.com">www.letpub.com</uri>) for its linguistic assistance during the preparation of this manuscript.</p></ack>
<fn-group><fn fn-type="other"><p><bold>Funding Statement:</bold> The authors received no specific funding for this study.</p></fn>
<fn fn-type="conflict"><p><bold>Conflicts of Interest:</bold> The authors declare that they have no conflicts of interest to report regarding the present study.</p></fn></fn-group>
<ref-list content-type="authoryear">
<title>References</title>
<ref id="ref-1"><label>[1]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>G. A.</given-names> <surname>Zsidisin</surname></string-name></person-group>, &#x201C;<article-title>A grounded definition of supply risk</article-title>,&#x201D; <source>Journal of Purchasing and Supply Management</source>, vol. <volume>9</volume>, no. <issue>5&#x2013;6</issue>, pp. <fpage>217</fpage>&#x2013;<lpage>224</lpage>, <year>2003</year>.</mixed-citation></ref>
<ref id="ref-2"><label>[2]</label><mixed-citation publication-type="book"><person-group person-group-type="author"><string-name><given-names>J.</given-names> <surname>Reason</surname></string-name></person-group>, <source>Managing the risks of organizational accidents</source>, <edition>1st ed.</edition>, <publisher-loc>London</publisher-loc>: <publisher-name>Routledge</publisher-name>, <year>2016</year>.</mixed-citation></ref>
<ref id="ref-3"><label>[3]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>W.</given-names> <surname>Ho</surname></string-name>, <string-name><given-names>T.</given-names> <surname>Zheng</surname></string-name>, <string-name><given-names>H.</given-names> <surname>Yildiz</surname></string-name> and <string-name><given-names>S.</given-names> <surname>Talluri</surname></string-name></person-group>, &#x201C;<article-title>Supply chain risk management: A literature review</article-title>,&#x201D; <source>International Journal of Production Research</source>, vol. <volume>53</volume>, no. <issue>16</issue>, pp. <fpage>5031</fpage>&#x2013;<lpage>5069</lpage>, <year>2015</year>.</mixed-citation></ref>
<ref id="ref-4"><label>[4]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>G. A.</given-names> <surname>Zsidisin</surname></string-name> and <string-name><given-names>L. M.</given-names> <surname>Ellram</surname></string-name></person-group>, &#x201C;<article-title>An agency theory investigation of supply risk management</article-title>,&#x201D; <source>The Journal of Supply Chain Management</source>, vol. <volume>39</volume>, no. <issue>3</issue>, pp. <fpage>15</fpage>&#x2013;<lpage>27</lpage>, <year>2003</year>.</mixed-citation></ref>
<ref id="ref-5"><label>[5]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>A.</given-names> <surname>Salamai</surname></string-name>, <string-name><given-names>O. K.</given-names> <surname>Hussain</surname></string-name>, <string-name><given-names>M.</given-names> <surname>Saberi</surname></string-name>, <string-name><given-names>E.</given-names> <surname>Chang</surname></string-name> and <string-name><given-names>F. K.</given-names> <surname>Hussain</surname></string-name></person-group>, &#x201C;<article-title>Highlighting the importance of considering the impacts of both external and internal risk factors on operational parameters to improve supply chain risk management</article-title>,&#x201D; <source>IEEE Access</source>, vol. <volume>7</volume>, no. <issue>1</issue>, pp. <fpage>49297</fpage>&#x2013;<lpage>49315</lpage>, <year>2019</year>.</mixed-citation></ref>
<ref id="ref-6"><label>[6]</label><mixed-citation publication-type="book"><person-group person-group-type="author"><string-name><given-names>N.</given-names> <surname>Slack</surname></string-name> and <string-name><given-names>A.</given-names> <surname>Brandon-Jones</surname></string-name></person-group>, <source>Operations and process management: Principles and practice for strategic impact</source>, <edition>5th ed.</edition>, <publisher-loc>Los Alamitos, CA, USA</publisher-loc>: <publisher-name>Pearson</publisher-name>, <year>2018</year>.</mixed-citation></ref>
<ref id="ref-7"><label>[7]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>J.</given-names> <surname>Chen</surname></string-name>, <string-name><given-names>A. S.</given-names> <surname>Sohal</surname></string-name> and <string-name><given-names>D. I.</given-names> <surname>Prajogo</surname></string-name></person-group>, &#x201C;<article-title>Supply chain operational risk mitigation: A collaborative approach</article-title>,&#x201D; <source>International Journal of Production Research</source>, vol. <volume>51</volume>, no. <issue>7</issue>, pp. <fpage>2186</fpage>&#x2013;<lpage>2199</lpage>, <year>2013</year>.</mixed-citation></ref>
<ref id="ref-8"><label>[8]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>D. A.</given-names> <surname>Rangel</surname></string-name>, <string-name><given-names>T. K.</given-names> <surname>de Oliveira</surname> </string-name> and <string-name><given-names>M. S. A.</given-names> <surname>Leite</surname></string-name></person-group>, &#x201C;<article-title>Supply chain risk classification: Discussion and proposal</article-title>,&#x201D; <source>International Journal of Production Research</source>, vol. <volume>53</volume>, no. <issue>22</issue>, pp. <fpage>6868</fpage>&#x2013;<lpage>6887</lpage>, <year>2014</year>.</mixed-citation></ref>
<ref id="ref-9"><label>[9]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>R.</given-names> <surname>Weijermars</surname></string-name>, <string-name><given-names>A.</given-names> <surname>Johnson</surname></string-name>, <string-name><given-names>J.</given-names> <surname>Denman</surname></string-name>, <string-name><given-names>K.</given-names> <surname>Salinas</surname></string-name> and <string-name><given-names>G.</given-names> <surname>Williams</surname></string-name></person-group>, &#x201C;<article-title>Creditworthiness of north american oil companies and minsky financing categories: Assessment of shifts due to the 2014&#x2013;2016 oil price shock</article-title>,&#x201D; <source>Journal of Functional Analysis</source>, vol. <volume>6</volume>, no. <issue>6</issue>, pp. <fpage>162</fpage>&#x2013;<lpage>180</lpage>, <year>2019</year>.</mixed-citation></ref>
<ref id="ref-10"><label>[10]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>F.</given-names> <surname>Aqlan</surname></string-name> and <string-name><given-names>S. S.</given-names> <surname>Lam</surname></string-name></person-group>, &#x201C;<article-title>A fuzzy-based integrated framework for supply chain risk assessment</article-title>,&#x201D; <source>International Journal of Production Economics</source>, vol. <volume>161</volume>, no. <issue>108</issue>, pp. <fpage>54</fpage>&#x2013;<lpage>63</lpage>, <year>2015</year>.</mixed-citation></ref>
<ref id="ref-11"><label>[11]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>N.</given-names> <surname>Carbonara</surname></string-name> and <string-name><given-names>R.</given-names> <surname>Pellegrino</surname></string-name></person-group>, &#x201C;<article-title>Real options approach to evaluate postponement as supply chain disruptions mitigation strategy</article-title>,&#x201D; <source>International Journal of Production Research</source>, vol. <volume>56</volume>, no. <issue>15</issue>, pp. <fpage>5249</fpage>&#x2013;<lpage>5271</lpage>, <year>2017</year>.</mixed-citation></ref>
<ref id="ref-12"><label>[12]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>C.</given-names> <surname>Colicchia</surname></string-name> and <string-name><given-names>F.</given-names> <surname>Strozzi</surname></string-name></person-group>, &#x201C;<article-title>Supply chain risk management: A new methodology for a systematic literature review</article-title>,&#x201D; <source>Supply Chain Management An International Journal</source>, vol. <volume>17</volume>, no. <issue>4</issue>, pp. <fpage>403</fpage>&#x2013;<lpage>418</lpage>, <year>2012</year>.</mixed-citation></ref>
<ref id="ref-13"><label>[13]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>R.</given-names> <surname>Pellegrino</surname></string-name>, <string-name><given-names>N.</given-names> <surname>Costantino</surname></string-name> and <string-name><given-names>D.</given-names> <surname>Tauro</surname></string-name></person-group>, &#x201C;<article-title>Supply chain finance: a supply chain-oriented perspective to mitigate commodity risk and pricing volatility</article-title>,&#x201D; <source>Journal of Purchasing and Supply Management</source>, vol. <volume>25</volume>, no. <issue>2</issue>, pp. <fpage>118</fpage>&#x2013;<lpage>133</lpage>, <year>2019</year>.</mixed-citation></ref>
<ref id="ref-14"><label>[14]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>D.</given-names> <surname>Ivanov</surname></string-name>, <string-name><given-names>A.</given-names> <surname>Dolgui</surname></string-name> and <string-name><given-names>B.</given-names> <surname>Sokolov</surname></string-name></person-group>, &#x201C;<article-title>The impact of digital technology and industry 4.0 on the ripple effect and supply chain risk analytics</article-title>,&#x201D; <source>International Journal of Production Research</source>, vol. <volume>57</volume>, no. <issue>3</issue>, pp. <fpage>829</fpage>&#x2013;<lpage>846</lpage>, <year>2018</year>.</mixed-citation></ref>
<ref id="ref-15"><label>[15]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>M. M.</given-names> <surname>Parast</surname></string-name> and <string-name><given-names>M.</given-names> <surname>Shekarian</surname></string-name></person-group>, &#x201C;<article-title>The impact of supply chain disruptions on organizational performance: A literature review</article-title>,&#x201D; <source>Springer Series in Supply Chain Management</source>, vol. <volume>7</volume>, pp. <fpage>367</fpage>&#x2013;<lpage>389</lpage>, <year>2018</year>.</mixed-citation></ref>
<ref id="ref-16"><label>[16]</label><mixed-citation publication-type="book"><person-group person-group-type="author"><string-name><given-names>A.</given-names> <surname>Salamai</surname></string-name>, <string-name><given-names>M.</given-names> <surname>Saberi</surname></string-name>, <string-name><given-names>O.</given-names> <surname>Hussain</surname></string-name> and <string-name><given-names>E.</given-names> <surname>Chang</surname></string-name></person-group>, &#x201C;<chapter-title>Risk identification-based association rule mining for supply chain big data</chapter-title>,&#x201D; in <source>Security, Privacy, and Anonymity in Computation, Communication, and Storage, LNCS</source>, vol. <volume>11342</volume>, pp. <fpage>219</fpage>&#x2013;<lpage>228</lpage>, <year>2018</year>.</mixed-citation></ref>
<ref id="ref-17"><label>[17]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>R.</given-names> <surname>Bello</surname></string-name>, <string-name><given-names>Y.</given-names> <surname>Gomez</surname></string-name>, <string-name><given-names>A.</given-names> <surname>Nowe</surname></string-name> and <string-name><given-names>M. M.</given-names> <surname>Garcia</surname></string-name></person-group>, &#x201C;<article-title>Two-step particle swarm optimization to solve the feature selection problem</article-title>,&#x201D; <source>Proc. ISDA</source>, vol. <volume>1</volume>, pp. <fpage>691</fpage>&#x2013;<lpage>696</lpage>, <year>2007</year>.</mixed-citation></ref>
<ref id="ref-18"><label>[18]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>A.</given-names> <surname>Ibrahim</surname></string-name>, <string-name><given-names>M.</given-names> <surname>Noshy</surname></string-name>, <string-name><given-names>H. A.</given-names> <surname>Ali</surname></string-name> and <string-name><given-names>M.</given-names> <surname>Badawy</surname></string-name></person-group>, &#x201C;<article-title>PAPSO: A poweraware VM placement technique based on particle swarm optimization</article-title>,&#x201D; <source>IEEE Access</source>, vol. <volume>8</volume>, no. <issue>1</issue>, pp. <fpage>81747</fpage>&#x2013;<lpage>81764</lpage>, <year>2020</year>.</mixed-citation></ref>
<ref id="ref-19"><label>[19]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>S.</given-names> <surname>Mirjalili</surname></string-name> and <string-name><given-names>A.</given-names> <surname>Lewis</surname></string-name></person-group>, &#x201C;<article-title>The whale optimization algorithm</article-title>,&#x201D; <source>Advances in Engineering Software</source>, vol. <volume>95</volume>, no. <issue>c</issue>, pp. <fpage>51</fpage>&#x2013;<lpage>67</lpage>, <year>2016</year>.</mixed-citation></ref>
<ref id="ref-20"><label>[20]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>E.-S. M.</given-names> <surname>El-kenawy</surname></string-name>, <string-name><given-names>A.</given-names> <surname>Ibrahim</surname></string-name>, <string-name><given-names>S.</given-names> <surname>Mirjalili</surname></string-name>, <string-name><given-names>M. M.</given-names> <surname>Eid</surname></string-name> and <string-name><given-names>S. E.</given-names> <surname>Hussein</surname></string-name></person-group>, &#x201C;<article-title>Novel feature selection and voting classifier algorithms for COVID-19 classification in CT images</article-title>,&#x201D; <source>IEEE Access</source>, vol. <volume>8</volume>, no. <issue>1</issue>, pp. <fpage>179317</fpage>&#x2013;<lpage>179335</lpage>, <year>2020</year>.</mixed-citation></ref>
<ref id="ref-21"><label>[21]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>E.-S. M.</given-names> <surname>El-kenawy</surname></string-name> and <string-name><given-names>M.</given-names> <surname>Eid</surname></string-name></person-group>, &#x201C;<article-title>Hybrid gray wolf and particle swarm optimization for feature selection</article-title>,&#x201D; <source>International Journal of Innovative Computing, Information and Control</source>, vol. <volume>16</volume>, no. <issue>3</issue>, pp. <fpage>831</fpage>&#x2013;<lpage>844</lpage>, <year>2020</year>.</mixed-citation></ref>
<ref id="ref-22"><label>[22]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>A.</given-names> <surname>Ibrahim</surname></string-name>, <string-name><given-names>A.</given-names> <surname>Tharwat</surname></string-name>, <string-name><given-names>T.</given-names> <surname>Gaber</surname></string-name> and <string-name><given-names>A. E.</given-names> <surname>Hassanien</surname></string-name></person-group>, &#x201C;<article-title>Optimized superpixel and adaboost classifier for human thermal face recognition</article-title>,&#x201D; <source>Signal, Image and Video Processing</source>, vol. <volume>12</volume>, pp. <fpage>711</fpage>&#x2013;<lpage>719</lpage>, <year>2018</year>.</mixed-citation></ref>
<ref id="ref-23"><label>[23]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>M. M.</given-names> <surname>Kabir</surname></string-name>, <string-name><given-names>M.</given-names> <surname>Shahjahan</surname></string-name> and <string-name><given-names>K.</given-names> <surname>Murase</surname></string-name></person-group>, &#x201C;<article-title>A new local search-based hybrid genetic algorithm for feature selection</article-title>,&#x201D; <source>Neurocomputing</source>, vol. <volume>74</volume>, no. <issue>17</issue>, pp. <fpage>2914</fpage>&#x2013;<lpage>2928</lpage>, <year>2011</year>.</mixed-citation></ref>
<ref id="ref-24"><label>[24]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>E.-S. M.</given-names> <surname>El-Kenawy</surname></string-name>, <string-name><given-names>M. M.</given-names> <surname>Eid</surname></string-name>, <string-name><given-names>M.</given-names> <surname>Saber</surname></string-name> and <string-name><given-names>A.</given-names> <surname>Ibrahim</surname></string-name></person-group>, &#x201C;<article-title>MbGWO-SFS: Modified binary grey wolf optimizer based on stochastic fractal search for feature selection</article-title>,&#x201D; <source>IEEE Access</source>, vol. <volume>8</volume>, no. <issue>1</issue>, pp. <fpage>107635</fpage>&#x2013;<lpage>107649</lpage>, <year>2020</year>.</mixed-citation></ref>
<ref id="ref-25"><label>[25]</label><mixed-citation publication-type="book"><person-group person-group-type="author"><string-name><given-names>R. L.</given-names> <surname>Kliem</surname></string-name> and <string-name><given-names>I. S.</given-names> <surname>Ludin</surname></string-name></person-group>, <source>Reducing project risk</source>, <edition>1st ed.</edition>, <publisher-loc>London, United Kingdom</publisher-loc>: <publisher-name>Routledge</publisher-name>, <year>2019</year>.</mixed-citation></ref>
<ref id="ref-26"><label>[26]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>L.</given-names> <surname>Tchankova</surname></string-name></person-group>, &#x201C;<article-title>Risk identification-basic stage in risk management</article-title>,&#x201D; <source>Environmental Management and Health</source>, vol. <volume>13</volume>, no. <issue>3</issue>, pp. <fpage>290</fpage>&#x2013;<lpage>297</lpage>, <year>2002</year>.</mixed-citation></ref>
<ref id="ref-27"><label>[27]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>T.</given-names> <surname>Aven</surname></string-name></person-group>, &#x201C;<article-title>Risk assessment and risk management: Review of recent advances on their foundation</article-title>,&#x201D; <source>European Journal of Operational Research</source>, vol. <volume>253</volume>, no. <issue>1</issue>, pp. <fpage>1</fpage>&#x2013;<lpage>13</lpage>, <year>2016</year>.</mixed-citation></ref>
<ref id="ref-28"><label>[28]</label><mixed-citation publication-type="book"><person-group person-group-type="author"><string-name><given-names>N. J.</given-names> <surname>Bahr</surname></string-name></person-group>, <source>System safety engineering and risk assessment</source>, <edition>2nd ed.</edition>, <publisher-loc>Boca Raton</publisher-loc>: <publisher-name>CRC Press</publisher-name>, <year>2018</year>.</mixed-citation></ref>
<ref id="ref-29"><label>[29]</label><mixed-citation publication-type="book"><person-group person-group-type="author"><string-name><given-names>M. L.</given-names> <surname>Brusseau</surname></string-name>, <string-name><given-names>I. L.</given-names> <surname>Pepper</surname></string-name> and <string-name><given-names>C. P.</given-names> <surname>Gerba</surname></string-name></person-group>, <source>Environmental and pollution science</source>, <edition>3rd ed.</edition>, <publisher-loc>London, United Kingdom</publisher-loc>: <publisher-name>Academic Press, Elsevier</publisher-name>, <year>2019</year>.</mixed-citation></ref>
<ref id="ref-30"><label>[30]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>K. P.</given-names> <surname>Scheibe</surname></string-name> and <string-name><given-names>J.</given-names> <surname>Blackhurst</surname></string-name></person-group>, &#x201C;<article-title>Supply chain disruption propagation: A systemic risk and normal accident theory perspective</article-title>,&#x201D; <source>International Journal of Production Research</source>, vol. <volume>56</volume>, no. <issue>1&#x2013;2</issue>, pp. <fpage>43</fpage>&#x2013;<lpage>59</lpage>, <year>2017</year>.</mixed-citation></ref>
<ref id="ref-31"><label>[31]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>G.</given-names> <surname>Behzadi</surname></string-name>, <string-name><given-names>M. J.</given-names> <surname>O&#x2019;Sullivan</surname></string-name>, <string-name><given-names>T. L.</given-names> <surname>Olsen</surname></string-name> and <string-name><given-names>A.</given-names> <surname>Zhang</surname></string-name></person-group>, &#x201C;<article-title>Agribusiness supply chain risk management: A review of quantitative decision models</article-title>,&#x201D; <source>Omega</source>, vol. <volume>79</volume>, no. <issue>c</issue>, pp. <fpage>21</fpage>&#x2013;<lpage>42</lpage>, <year>2018</year>.</mixed-citation></ref>
<ref id="ref-32"><label>[32]</label><mixed-citation publication-type="other"><collab>Logic manager</collab>, <article-title>Supply Chain Risk Management Software</article-title>, <year>2021</year>. [Online]. Available: <uri xlink:href="https://www.logicmanager.com/erm-software/plugins/supply-chain-risk-management-software/">https://www.logicmanager.com/erm-software/plugins/supply-chain-risk-management-software/</uri>, Accessed: 2021-3-21.</mixed-citation></ref>
<ref id="ref-33"><label>[33]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>A.</given-names> <surname>Ibrahim</surname></string-name>, <string-name><given-names>S.</given-names> <surname>Mohammed</surname></string-name>, <string-name><given-names>H. A.</given-names> <surname>Ali</surname></string-name> and <string-name><given-names>S. E.</given-names> <surname>Hussein</surname></string-name></person-group>, &#x201C;<article-title>Breast cancer segmentation from thermal images based on chaotic salp swarm algorithm</article-title>,&#x201D; <source>IEEE Access</source>, vol. <volume>8</volume>, no. <issue>1</issue>, pp. <fpage>122121</fpage>&#x2013;<lpage>122134</lpage>, <year>2020</year>.</mixed-citation></ref>
<ref id="ref-34"><label>[34]</label><mixed-citation publication-type="conf-proc"><person-group person-group-type="author"><string-name><given-names>A.</given-names> <surname>Ibrahim</surname></string-name>, <string-name><given-names>H. A.</given-names> <surname>Ali</surname></string-name>, <string-name><given-names>M. M.</given-names> <surname>Eid</surname></string-name> and <string-name><given-names>E.-S. M.</given-names> <surname>El-Kenawy</surname></string-name></person-group>, &#x201C;<article-title>Chaotic harris hawks optimization for unconstrained function optimization</article-title>,&#x201D; in <conf-name>2020 16th Int. Computer Engineering Conf.</conf-name>, <publisher-loc>Cairo, Egypt</publisher-loc>, <publisher-name>IEEE</publisher-name>, pp. <fpage>153</fpage>&#x2013;<lpage>158</lpage>, <year>2020</year>.</mixed-citation></ref>
<ref id="ref-35"><label>[35]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>M. M.</given-names> <surname>Eid</surname></string-name>, <string-name><given-names>E.-S. M.</given-names> <surname>El-Kenawy</surname></string-name> and <string-name><given-names>A.</given-names> <surname>Ibrahim</surname></string-name></person-group>, &#x201C;<article-title>Anemia estimation for covid-19 patients using a machine learning model</article-title>,&#x201D; <source>Journal of Computer Science and Information Systems</source>, vol. <volume>17</volume>, no. <issue>11</issue>, pp. <fpage>1</fpage>&#x2013;<lpage>7</lpage>, <year>2021</year>.</mixed-citation></ref>
<ref id="ref-36"><label>[36]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>E. M.</given-names> <surname>Hassib</surname></string-name>, <string-name><given-names>A. I.</given-names> <surname>El-Desouky</surname></string-name>, <string-name><given-names>L. M.</given-names> <surname>Labib</surname></string-name> and <string-name><given-names>E.-S. M. T.</given-names> <surname>El-Kenawy</surname></string-name></person-group>, &#x201C;<article-title>WOA + BRNN: An imbalanced big data classification framework using whale optimization and deep neural network</article-title>,&#x201D; <source>Soft Computing</source>, vol. <volume>24</volume>, no. <issue>8</issue>, pp. <fpage>5573</fpage>&#x2013;<lpage>5592</lpage>, <year>2020</year>.</mixed-citation></ref>
<ref id="ref-37"><label>[37]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>H. R.</given-names> <surname>Hussien</surname></string-name>, <string-name><given-names>E.-S. M.</given-names> <surname>El-Kenawy</surname></string-name> and <string-name><given-names>A. I.</given-names> <surname>El-Desouky</surname></string-name></person-group>, &#x201C;<article-title>EEG channel selection using a modified grey wolf optimizer</article-title>,&#x201D; <source>European Journal of Electrical Engineering and Computer Science</source>, vol. <volume>5</volume>, no. <issue>1</issue>, pp. <fpage>17</fpage>&#x2013;<lpage>24</lpage>, <year>2021</year>.</mixed-citation></ref>
<ref id="ref-38"><label>[38]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>A.</given-names> <surname>Elhosuieny</surname></string-name>, <string-name><given-names>M.</given-names> <surname>Salem</surname></string-name>, <string-name><given-names>A.</given-names> <surname>Thabet</surname></string-name> and <string-name><given-names>A.</given-names> <surname>Ibrahim</surname></string-name></person-group>, &#x201C;<article-title>ADOMC-NPR automatic decision-making offloading framework for mobile computation using nonlinear polynomial regression model</article-title>,&#x201D; <source>International Journal of Web Services Research</source>, vol. <volume>16</volume>, no. <issue>4</issue>, pp. <fpage>53</fpage>&#x2013;<lpage>73</lpage>, <year>2019</year>.</mixed-citation></ref>
<ref id="ref-39"><label>[39]</label><mixed-citation publication-type="conf-proc"><person-group person-group-type="author"><string-name><given-names>A.</given-names> <surname>Ibrahim</surname></string-name>, <string-name><given-names>A.</given-names> <surname>Ahmed</surname></string-name>, <string-name><given-names>S.</given-names> <surname>Hussein</surname></string-name> and <string-name><given-names>A. E.</given-names> <surname>Hassanien</surname></string-name></person-group>, &#x201C;<article-title>Fish image segmentation using salp swarm algorithm</article-title>,&#x201D; in <conf-name>Proc. Int. Conf. on Advanced Machine Learning Technologies and Applications, Advances in Intelligent Systems and Computing</conf-name>, vol. <volume>723</volume>, <publisher-loc>Cham</publisher-loc>, <publisher-name>Springer</publisher-name>, <year>2018</year>.</mixed-citation></ref>
<ref id="ref-40"><label>[40]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>B.</given-names> <surname>Tjahjono</surname></string-name>, <string-name><given-names>C.</given-names> <surname>Esplugues</surname></string-name>, <string-name><given-names>E.</given-names> <surname>Ares</surname></string-name> and <string-name><given-names>G.</given-names> <surname>Pelaez</surname></string-name></person-group>, &#x201C;<article-title>What does industry 4.0 mean to supply chain?</article-title>,&#x201D; <source>Procedia Manufacturing</source>, vol. <volume>13</volume>, pp. <fpage>1175</fpage>&#x2013;<lpage>1182</lpage>, <year>2017</year>.</mixed-citation></ref>
<ref id="ref-41"><label>[41]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>H.</given-names> <surname>Lasi</surname></string-name>, <string-name><given-names>P.</given-names> <surname>Fettke</surname></string-name>, <string-name><given-names>H.-G.</given-names> <surname>Kemper</surname></string-name>, <string-name><given-names>T.</given-names> <surname>Feld</surname></string-name> and <string-name><given-names>M.</given-names> <surname>Hoffmann</surname></string-name></person-group>, &#x201C;<article-title>Industry 4.0</article-title>,&#x201D; <source>Business &#x0026; Information Systems Engineering</source>, vol. <volume>6</volume>, no. <issue>4</issue>, pp. <fpage>239</fpage>&#x2013;<lpage>242</lpage>, <year>2014</year>.</mixed-citation></ref>
<ref id="ref-42"><label>[42]</label><mixed-citation publication-type="conf-proc"><person-group person-group-type="author"><string-name><given-names>A.</given-names> <surname>Salamai</surname></string-name>, <string-name><given-names>O.</given-names> <surname>Hussain</surname></string-name> and <string-name><given-names>M.</given-names> <surname>Saberi</surname></string-name></person-group>, &#x201C;<article-title>Decision support system for risk assessment using fuzzy inference in supply chain big data</article-title>,&#x201D; in <conf-name>Proc. 2019 Int. Conf. on High Performance Big Data and Intelligent Systems</conf-name>, <publisher-loc>Shenzhen, China</publisher-loc>, pp. <fpage>248</fpage>&#x2013;<lpage>253</lpage>, <year>2019</year>.</mixed-citation></ref>
<ref id="ref-43"><label>[43]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>D. D.</given-names> <surname>Wu</surname></string-name>, <string-name><given-names>S.-H.</given-names> <surname>Chen</surname></string-name> and <string-name><given-names>D. L.</given-names> <surname>Olson</surname></string-name></person-group>, &#x201C;<article-title>Business intelligence in risk management: Some recent progresses</article-title>,&#x201D; <source>Information Sciences</source>, vol. <volume>256</volume>, pp. <fpage>1</fpage>&#x2013;<lpage>7</lpage>, <year>2014</year>.</mixed-citation></ref>
<ref id="ref-44"><label>[44]</label><mixed-citation publication-type="conf-proc"><person-group person-group-type="author"><string-name><given-names>G.</given-names> <surname>K&#322;osowski</surname></string-name> and <string-name><given-names>A.</given-names> <surname>Gola</surname></string-name></person-group>, &#x201C;<article-title>Risk-based estimation of manufacturing order costs with artificial intelligence</article-title>,&#x201D; in <conf-name>Proc. of the 2016 Federated Conf. on Computer Science and Information Systems</conf-name>, Gdansk, Poland, <publisher-name>IEEE</publisher-name>, vol. <volume>8</volume>, pp. <fpage>729</fpage>&#x2013;<lpage>732</lpage>, <year>2016</year>.</mixed-citation></ref>
<ref id="ref-45"><label>[45]</label><mixed-citation publication-type="book"><person-group person-group-type="author"><string-name><given-names>V. C.</given-names> <surname>M&#x00FC;ller</surname></string-name> and <string-name><given-names>N.</given-names> <surname>Bostrom</surname></string-name></person-group>, &#x201C;<chapter-title>Future progress in artificial intelligence: A survey of expert opinion</chapter-title>,&#x201D; in <source>Fundamental Issues of Artificial Intelligence</source>, vol. <volume>376</volume>, <publisher-loc>Cham, Switzerland</publisher-loc>: <publisher-name>Springer International Publishing</publisher-name>, pp. <fpage>555</fpage>&#x2013;<lpage>572</lpage>, <year>2016</year>.</mixed-citation></ref>
<ref id="ref-46"><label>[46]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>G.</given-names> <surname>Baryannis</surname></string-name>, <string-name><given-names>S.</given-names> <surname>Validi</surname></string-name>, <string-name><given-names>S.</given-names> <surname>Dani</surname></string-name> and <string-name><given-names>G.</given-names> <surname>Antoniou</surname></string-name></person-group>, &#x201C;<article-title>Supply chain risk management and artificial intelligence: State of the art and future research directions</article-title>,&#x201D; <source>International Journal of Production Research</source>, vol. <volume>57</volume>, no. <issue>7</issue>, pp. <fpage>2179</fpage>&#x2013;<lpage>2202</lpage>, <year>2018</year>.</mixed-citation></ref>
<ref id="ref-47"><label>[47]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>S.</given-names> <surname>Mirjalili</surname></string-name></person-group>, &#x201C;<article-title>SCA: A sine cosine algorithm for solving optimization problems</article-title>,&#x201D; <source>Knowledge-Based Systems</source>, vol. <volume>96</volume>, pp. <fpage>120</fpage>&#x2013;<lpage>133</lpage>, <year>2016</year>.</mixed-citation></ref>
<ref id="ref-48"><label>[48]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>A.</given-names> <surname>Tharwat</surname></string-name></person-group>, &#x201C;<article-title>Parameter investigation of support vector machine classifier with kernel functions</article-title>,&#x201D; <source>Knowledge and Information Systems</source>, vol. <volume>61</volume>, pp. <fpage>1269</fpage>&#x2013;<lpage>1302</lpage>, <year>2019</year>.</mixed-citation></ref>
<ref id="ref-49"><label>[49]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>E.-S. M.</given-names> <surname>El-Kenawy</surname></string-name>, <string-name><given-names>S.</given-names> <surname>Mirjalili</surname></string-name>, <string-name><given-names>A.</given-names> <surname>Ibrahim</surname></string-name>, <string-name><given-names>M.</given-names> <surname>Alrahmawy</surname></string-name> and <string-name><given-names>M.</given-names> <surname>El-Said</surname></string-name></person-group>, &#x201C;<article-title>Advanced meta-heuristics, convolutional neural networks, and feature selectors for efficient COVID-19 X-ray chest image classification</article-title>,&#x201D; <source>IEEE Access</source>, vol. <volume>9</volume>, pp. <fpage>36019</fpage>&#x2013;<lpage>36037</lpage>, <year>2021</year>.</mixed-citation></ref>
<ref id="ref-50"><label>[50]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>M. M.</given-names> <surname>Fouad</surname></string-name>, <string-name><given-names>A. I.</given-names> <surname>El-Desouky</surname></string-name>, <string-name><given-names>R.</given-names> <surname>Al-Hajj</surname></string-name> and <string-name><given-names>E.-S. M.</given-names> <surname>El-Kenawy</surname></string-name></person-group>, &#x201C;<article-title>Dynamic group-based cooperative optimization algorithm</article-title>,&#x201D; <source>IEEE Access</source>, vol. <volume>8</volume>, pp. <fpage>148378</fpage>&#x2013;<lpage>148403</lpage>, <year>2020</year>.</mixed-citation></ref>
<ref id="ref-51"><label>[51]</label><mixed-citation publication-type="journal"><person-group person-group-type="author"><string-name><given-names>L.</given-names> <surname>Breiman</surname></string-name></person-group>, &#x201C;<article-title>Random forests</article-title>,&#x201D; <source>Machine Learning</source>, vol. <volume>45</volume>, no. <issue>1</issue>, pp. <fpage>5</fpage>&#x2013;<lpage>32</lpage>, <year>2001</year>.</mixed-citation></ref>
</ref-list>
</back>
</article>